.*?<\/code><\/pre>/s', function($matches) {
            return htmlspecialchars_decode($matches[0]);
        }, $_POST['message']);

        // Then apply sanitization
        $message = wp_kses($message, $allowed_tags);

        // Preserve code blocks from markdown conversion
        $message = preg_replace('/```(\w+)?\s*([\s\S]+?)```/s', '
$2
', $message);
        $message = apply_filters('mxchat_filter_message', $message, 'prompt', $session_id);

    // ===== SIMPLIFIED TESTING PANEL INITIALIZATION =====
        // Always initialize testing data for admins (no toggle needed)
        $testing_data = null;
        if (current_user_can('administrator')) {
            // For vision messages, use the original user message for the query display
            $query_for_testing = $message;
            if (isset($_POST['vision_processed']) && $_POST['vision_processed'] && isset($_POST['original_user_message'])) {
                $query_for_testing = sanitize_textarea_field($_POST['original_user_message']);
            }
            
            $testing_data = [
                'query' => $query_for_testing,
                'timestamp' => time(),
                'top_matches' => [],
                'action_matches' => [], //   Initialize action matches array
                'page_context' => $page_context, //   Include page context in testing data
                'is_vision' => isset($_POST['vision_processed']) && $_POST['vision_processed'],
                'bot_id' => $bot_id //   Include bot ID in testing data
            ];
            
            // Get similarity threshold from bot options or default options
            $similarity_threshold = isset($current_options['similarity_threshold']) 
                ? ((int) $current_options['similarity_threshold']) / 100 
                : 0.35;
            
            $testing_data['similarity_threshold'] = $similarity_threshold;
            
            // Determine knowledge base type using bot-specific config
            $bot_pinecone_config = $this->get_bot_pinecone_config($bot_id);
            $use_pinecone = isset($bot_pinecone_config['use_pinecone']) ? $bot_pinecone_config['use_pinecone'] : false;
            $testing_data['knowledge_base_type'] = $use_pinecone ? 'Pinecone' : 'WordPress Database';
        }
        // ===== END SIMPLIFIED TESTING INITIALIZATION =====

    // Add debug before and after:
    //error_log('MxChat Core: About to call mxchat_pre_process_message filter with message: ' . $message);
    $pre_processed_result = apply_filters('mxchat_pre_process_message', $message, $user_id, $session_id);
    //error_log('MxChat Core: Filter returned: ' . (is_array($pre_processed_result) ? 'array' : $pre_processed_result));


        // If the pre-processing returned a result (not the original message), use it directly
        if (is_array($pre_processed_result) && isset($pre_processed_result['text'])) {
            // Save the AI response
            $this->mxchat_save_chat_message($session_id, 'bot', $pre_processed_result['text']);
            
            // Save HTML content if provided
            if (!empty($pre_processed_result['html'])) {
                $this->mxchat_save_chat_message($session_id, 'bot', $pre_processed_result['html']);
            }
            
            // Add testing data if admin
            $response_data = [
                'text' => $pre_processed_result['text'],
                'html' => $pre_processed_result['html'] ?? '',
                'session_id' => $session_id
            ];
            
            if ($testing_data !== null) {
                $response_data['testing_data'] = $testing_data;
            }
            
            wp_send_json($response_data);
            wp_die();
        }

        // Save the user's message - handle vision processed messages differently
        if (isset($_POST['vision_processed']) && $_POST['vision_processed'] && isset($_POST['original_user_message'])) {
            // For vision messages, save the original user message with image indicator
            $original_message = sanitize_textarea_field($_POST['original_user_message']);
            if (isset($_POST['vision_images_count']) && $_POST['vision_images_count'] > 0) {
                $image_count = intval($_POST['vision_images_count']);
                $original_message .= " [{$image_count} image(s)]";
            }
            $this->mxchat_save_chat_message($session_id, 'user', $original_message);
        } else {
            // Regular message - save as normal
            $this->mxchat_save_chat_message($session_id, 'user', $message);
        }

        
    if (is_email($message)) {
            // Add the email to Loops
            $this->add_email_to_loops($message);
            
            // Get the user's success message instruction using current_options
            $user_success_message = $current_options['email_capture_response'] ?? __('Thank you for providing your email! You\'ve been added to our list.', 'mxchat');
            
            // Set instruction for AI using the user's success message
            $this->current_action_instruction = $user_success_message;
            
            // Clear the email capture transient since we got the email
            delete_transient('mxchat_email_capture_' . $user_id);
        }
        
        //   Check if we're in an email capture flow but user hasn't provided email yet
        elseif (get_transient('mxchat_email_capture_' . $user_id)) {
            // Check if the message contains an email (not the whole message being an email)
            if (preg_match('/\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b/', $message, $matches)) {
                $extracted_email = $matches[0];
                
                // Add the extracted email to Loops
                $this->add_email_to_loops($extracted_email);
                
                // Get the user's success message instruction using current_options
                $user_success_message = $current_options['email_capture_response'] ?? __('Thank you for providing your email! You\'ve been added to our list.', 'mxchat');
                
                // Set instruction for AI using the user's success message
                $this->current_action_instruction = $user_success_message;
                
                // Clear the email capture transient since we got the email
                delete_transient('mxchat_email_capture_' . $user_id);
            }
            // If no email found but we're in capture mode, remind them
            else {
                // Get the original instruction to remind them using current_options
                $original_instruction = $current_options['triggered_phrase_response'] ?? __("Please provide your email address.", 'mxchat');
                $this->current_action_instruction = $original_instruction;
            }
        }

        $intent_info = '';

        // Check chat mode
        $chat_mode = get_option("mxchat_mode_{$session_id}", 'ai');

        // Handle agent mode
    // Handle agent mode
        if ($chat_mode === 'agent') {
            // First, check for switch intent before doing anything else
            $intent_matched = $this->mxchat_check_intent_and_invoke_callback($message, $user_id, $session_id);

            //   Capture action analysis for testing panel after intent check
            if ($testing_data !== null && isset($this->last_action_analysis) && !empty($this->last_action_analysis)) {
                $testing_data['action_matches'] = $this->last_action_analysis;
            }
            
            // Around line 506, in the agent mode handling section:
            if ($intent_matched && !empty($this->fallbackResponse['text'])) {
                // Update chat mode first
                update_option("mxchat_mode_{$session_id}", 'ai');
            
                // Clear any existing PDF context to start fresh
                $this->clear_pdf_transients($session_id);
            
                // Prepare clean switch response with explicit chat_mode
                $response_data = [
                    'text' => $this->fallbackResponse['text'],
                    'html' => $this->fallbackResponse['html'] ?? '',
                    'session_id' => $session_id,
                    'chat_mode' => 'ai' // EXPLICITLY SET THIS
                ];
            
                if ($testing_data !== null) {
                    $response_data['testing_data'] = $testing_data;
                }
            
                // Save the mode switch message
                $this->mxchat_save_chat_message($session_id, 'system', esc_html__('Switched to AI chat mode', 'mxchat'));
                $this->mxchat_save_chat_message($session_id, 'bot', $this->fallbackResponse['text']);
            
                // Send response and exit
                wp_send_json($response_data);
                wp_die();
            } elseif (!$intent_matched) {
                // No intent matched, handle live agent message
                try {
                    $this->mxchat_send_user_message_to_agent($message, $user_id, $session_id);

                    $agent_response = [
                        'status' => 'waiting_for_agent',
                        'message' => esc_html__('Message sent to live agent.', 'mxchat')
                    ];
                    
                    if ($testing_data !== null) {
                        $agent_response['testing_data'] = $testing_data;
                    }

                    wp_send_json_success($agent_response);
                } catch (\Exception $e) {
                    wp_send_json_error(esc_html__('Failed to send message to agent', 'mxchat'));
                }
                wp_die();
            }
        }

        // Step 1: Check for new PDF URL in the message
        if (!isset($_POST['vision_processed']) && preg_match('/https?:\/\/[^\s"]+/i', $message, $matches)) {
            $new_pdf_url = $matches[0];

            // Check if this is likely a PDF-related request
            $pdf_keywords = ['pdf', 'document', 'read', 'analyze'];
            $is_pdf_request = false;

            foreach ($pdf_keywords as $keyword) {
                if (stripos($message, $keyword) !== false) {
                    $is_pdf_request = true;
                    break;
                }
            }

            // If it looks like a PDF request or we're waiting for a PDF URL
            if ($is_pdf_request || get_transient('mxchat_waiting_for_pdf_url_' . $session_id)) {
                // Validate HTTPS
                if (wp_http_validate_url($new_pdf_url) && parse_url($new_pdf_url, PHP_URL_SCHEME) === 'https') {
                    // Extract filename from URL
                    $pdf_filename = basename(parse_url($new_pdf_url, PHP_URL_PATH));

                    // Clear previous PDF transients
                    $this->clear_pdf_transients($session_id);

                    // Process new PDF using current_options
                    $max_pages = $current_options['pdf_max_pages'] ?? 69;
                    $embeddings = $this->fetch_and_split_pdf_pages($new_pdf_url, $max_pages);

                    if ($embeddings === 'too_many_pages') {
                        $error_text = sprintf(
                            $current_options['pdf_intent_error_text'] ??
                            esc_html__("The provided PDF exceeds the maximum allowed limit of %d pages. Please provide a smaller document.", 'mxchat'),
                            $max_pages
                        );
                        $this->fallbackResponse['text'] = $error_text;
                    } elseif ($embeddings) {
                        // Store new PDF information
                        $pdf_filename = basename(parse_url($new_pdf_url, PHP_URL_PATH));

                        // If the filename is generic, create a more descriptive one
                        if (in_array($pdf_filename, ['results_download.php', 'download.php', 'view.php', 'pdf.php']) ||
                            strpos($pdf_filename, '.php') !== false) {
                            $pdf_filename = 'Document_' . date('Y-m-d_H-i') . '.pdf';
                        }

                        set_transient('mxchat_pdf_url_' . $session_id, $new_pdf_url, HOUR_IN_SECONDS);
                        set_transient('mxchat_pdf_filename_' . $session_id, $pdf_filename, HOUR_IN_SECONDS);
                        set_transient('mxchat_pdf_embeddings_' . $session_id, $embeddings, HOUR_IN_SECONDS);
                        set_transient('mxchat_include_pdf_in_context_' . $session_id, true, HOUR_IN_SECONDS);

                        $success_text = $current_options['pdf_intent_success_text'] ??
                            esc_html__("I've processed the new PDF '{$pdf_filename}'. What questions do you have about it?", 'mxchat');

                        $pdf_response = [
                            'success' => true,
                            'message' => $success_text,
                            'data' => [
                                'filename' => $pdf_filename
                            ]
                        ];
                        
                        if ($testing_data !== null) {
                            $pdf_response['testing_data'] = $testing_data;
                        }

                        wp_send_json($pdf_response);
                        wp_die();
                    } else {
                        $error_text = $current_options['pdf_intent_error_text'] ??
                            esc_html__("Sorry, I couldn't process the PDF. Please ensure it's a valid file.", 'mxchat');
                        $this->fallbackResponse['text'] = $error_text;
                    }

                    $pdf_error_response = [
                        'success' => false,
                        'message' => $this->fallbackResponse['text']
                    ];
                    
                    if ($testing_data !== null) {
                        $pdf_error_response['testing_data'] = $testing_data;
                    }

                    wp_send_json($pdf_error_response);
                    wp_die();
                }
            }
        }


        // Step 2: Detect intent and handle intent-based responses
        $intent_result = $this->mxchat_check_intent_and_invoke_callback($message, $user_id, $session_id);

        //   Capture action analysis for testing panel after intent check
        if ($testing_data !== null && isset($this->last_action_analysis) && !empty($this->last_action_analysis)) {
            $testing_data['action_matches'] = $this->last_action_analysis;
        }

        // Step 3: Handle the intent result appropriately
        if ($intent_result !== false) {
            // Intent was matched - ALWAYS send as JSON response, never streaming
            
            if (is_array($intent_result) && (isset($intent_result['text']) || isset($intent_result['html']))) {
                // Intent returned a direct response array
                $response_data = [
                    'text' => $intent_result['text'] ?? '',
                    'html' => $intent_result['html'] ?? '',
                    'session_id' => $session_id
                ];

                // IMPORTANT: Include chat_mode if present (for WhatsApp, Slack, etc.)
                if (isset($intent_result['chat_mode'])) {
                    $response_data['chat_mode'] = $intent_result['chat_mode'];
                }

                if ($testing_data !== null) {
                    $response_data['testing_data'] = $testing_data;
                }

                wp_send_json($response_data);
                wp_die();
            } else if ($intent_result === true && (!empty($this->fallbackResponse['text']) || !empty($this->fallbackResponse['html']))) {
                // Intent returned true and set fallbackResponse

                // SAVE TO TRANSCRIPT
                if (!empty($this->fallbackResponse['text'])) {
                    $this->mxchat_save_chat_message($session_id, 'bot', $this->fallbackResponse['text']);
                }
                // Save action HTML (product cards, featured products, etc.) so it renders in transcripts
                if (!empty($this->fallbackResponse['html'])) {
                    $this->mxchat_save_chat_message($session_id, 'bot', $this->fallbackResponse['html']);
                }

                $response_data = [
                    'text' => $this->fallbackResponse['text'] ?? '',
                    'html' => $this->fallbackResponse['html'] ?? '',
                    'session_id' => $session_id
                ];

                if (isset($this->fallbackResponse['chat_mode'])) {
                    $response_data['chat_mode'] = $this->fallbackResponse['chat_mode'];
                }

                if ($testing_data !== null) {
                    $response_data['testing_data'] = $testing_data;
                }

                wp_send_json($response_data);
                wp_die();
            }
        }

        // If we get here, no intent matched OR the intent didn't provide a usable response

        // Step 4: Generate AI response
        // Get session start timestamp - when persistence is OFF, only include messages from this page load
        $session_start_timestamp = isset($_POST['session_start_timestamp']) ? intval($_POST['session_start_timestamp']) : 0;
        $conversation_history = $this->mxchat_fetch_conversation_history_for_ai($session_id, $session_start_timestamp);
        $this->mxchat_increment_chat_count();
        
        // Generate embedding for the user's query - USE BOT-SPECIFIC API KEY
        $api_key = $current_options['api_key'] ?? $this->options['api_key'];
        $user_message_embedding = $this->mxchat_generate_embedding($message, $api_key);
        
        // Check if the embedding generation returned an error
        if (is_array($user_message_embedding) && isset($user_message_embedding['error'])) {
            $error_message = $user_message_embedding['error'];
            $error_code = $user_message_embedding['error_code'] ?? 'embedding_error';

            // FIXED: Send error in appropriate format based on streaming mode
            if ($is_streaming) {
                echo "data: " . json_encode([
                    'error' => true,
                    'error_message' => $error_message,
                    'error_code' => $error_code,
                    'text' => $error_message,
                    'message' => $error_message
                ]) . "\n\n";
                echo "data: [DONE]\n\n";
                flush();
            } else {
                wp_send_json_error([
                    'error_message' => $error_message,
                    'error_code' => $error_code
                ]);
            }
            wp_die();
        }

        // Check if the embedding is valid
        if (!is_array($user_message_embedding) || empty($user_message_embedding)) {
            $error_message = esc_html__('Unable to process your message. The embedding service is not responding correctly.', 'mxchat');

            // FIXED: Send error in appropriate format based on streaming mode
            if ($is_streaming) {
                echo "data: " . json_encode([
                    'error' => true,
                    'error_message' => $error_message,
                    'error_code' => 'invalid_embedding',
                    'text' => $error_message,
                    'message' => $error_message
                ]) . "\n\n";
                echo "data: [DONE]\n\n";
                flush();
            } else {
                wp_send_json_error([
                    'error_message' => $error_message,
                    'error_code' => 'invalid_embedding'
                ]);
            }
            wp_die();
        }

        // Build context with both knowledge base and PDF content if available
        $context_content = "User asked: '{$message}'\n\n";
        
        //   Add action instruction if present (add this right after the above line)
        if (!empty($this->current_action_instruction)) {
            $context_content .= "===== SPECIAL INSTRUCTION =====\n";
            $context_content .= "IMPORTANT: " . $this->current_action_instruction . "\n";
            $context_content .= "Respond naturally and conversationally while following this instruction.\n";
            $context_content .= "===== END SPECIAL INSTRUCTION =====\n\n";
            
            // Clear the instruction after using it
            $this->current_action_instruction = null;
        }


        //   Add page context if available and contextual awareness is enabled using current_options
        if ($page_context && isset($current_options['contextual_awareness_toggle']) && $current_options['contextual_awareness_toggle'] === 'on') {
            $context_content .= "===== CURRENT PAGE CONTEXT =====\n";
            $context_content .= "Page URL: " . $page_context['url'] . "\n";
            $context_content .= "Page Title: " . $page_context['title'] . "\n";
            $context_content .= "Page Content: " . $page_context['content'] . "\n";
            $context_content .= "===== END CURRENT PAGE CONTEXT =====\n\n";
        }

        // Get relevant content from knowledge base - PASS BOT_ID and MESSAGE for Vector Store
        $relevant_content = $this->mxchat_find_relevant_content($user_message_embedding, $bot_id, $message);
        
        // NEW: Also extract URLs from system instructions (only if citation links enabled)
        // Use fresh options to ensure we get the latest setting value
        $fresh_options = get_option('mxchat_options', []);
        $citation_links_enabled = isset($fresh_options['citation_links_toggle']) ? ($fresh_options['citation_links_toggle'] === 'on') : true;

        $system_instructions = $this->get_system_instructions($bot_id, $session_id);
        if ($citation_links_enabled && !empty($system_instructions)) {
            preg_match_all(
                '#\bhttps?://[^\s<>"\']+#i',
                $system_instructions,
                $system_instruction_urls
            );

            if (!empty($system_instruction_urls[0])) {
                // Merge with existing valid URLs
                $this->current_valid_urls = array_merge(
                    $this->current_valid_urls,
                    $system_instruction_urls[0]
                );
                // Remove duplicates
                $this->current_valid_urls = array_unique($this->current_valid_urls);

                //error_log("Added " . count($system_instruction_urls[0]) . " URLs from system instructions");
            }
        }
        
// ===== CAPTURE REAL SIMILARITY DATA FOR ADMINS =====
if ($testing_data !== null && $this->last_similarity_analysis !== null) {
    // Update testing data with the REAL similarity analysis
    $testing_data['top_matches'] = $this->last_similarity_analysis['top_matches'];
    $testing_data['total_documents_checked'] = $this->last_similarity_analysis['total_checked'] ?? 0;
    $testing_data['knowledge_base_type'] = $this->last_similarity_analysis['knowledge_base_type'];
    $testing_data['sources_used'] = $this->last_similarity_analysis['sources_used'] ?? 0;
    $testing_data['total_chunks_used'] = $this->last_similarity_analysis['total_chunks_used'] ?? 0;
}
// ===== END SIMILARITY DATA CAPTURE =====

// NEW: Add valid URLs to testing data for admin panel display (AFTER similarity data)
if ($testing_data !== null && !empty($this->current_valid_urls)) {
    $testing_data['approved_urls'] = array_values($this->current_valid_urls);
    //error_log("Added " . count($this->current_valid_urls) . " approved URLs to testing data");
}
        
        $kb_block = !empty($relevant_content)
            ? "===== OFFICIAL KNOWLEDGE DATABASE CONTENT =====\n" . $relevant_content . "\n===== END OF OFFICIAL KNOWLEDGE DATABASE CONTENT =====\n\n"
            : "===== NO RELEVANT CONTENT FOUND IN KNOWLEDGE DATABASE =====\n";

        // {context} placeholder (plan 59bc1b): when the resolved instructions
        // carry the token, the KB block is injected at that spot by
        // get_system_instructions() (every provider handler re-calls it) and is
        // NOT appended here — otherwise the block would ride twice.
        // $system_instructions above was resolved while context_kb_block was
        // still null, so the literal token is still visible for this check.
        if (!empty($system_instructions) && stripos($system_instructions, '{context}') !== false) {
            $this->context_kb_block = $kb_block;
        } else {
            $context_content .= $kb_block;
        }
        
        // NEW: Add approved URLs list to context for AI (only if citation links enabled)
        if ($citation_links_enabled && !empty($this->current_valid_urls)) {
            $context_content .= "===== APPROVED URLS FOR CITATIONS =====\n";
            $context_content .= "You may ONLY use these exact URLs in your response:\n";
            foreach ($this->current_valid_urls as $url) {
                $context_content .= "- " . $url . "\n";
            }
            $context_content .= "\nCRITICAL: Do NOT create, modify, extend, or invent any other URLs. ";
            $context_content .= "===== END APPROVED URLS =====\n\n";
        }
        
        // Check for and include PDF content
        $pdf_url = get_transient('mxchat_pdf_url_' . $session_id);
        $pdf_embeddings = get_transient('mxchat_pdf_embeddings_' . $session_id);
        $pdf_filename = get_transient('mxchat_pdf_filename_' . $session_id);
        if ($pdf_url && $pdf_embeddings && get_transient('mxchat_include_pdf_in_context_' . $session_id)) {
            $relevant_pdf_pages = $this->find_relevant_pdf_pages($user_message_embedding, $pdf_embeddings);
            if (!empty($relevant_pdf_pages)) {
                $context_content .= "Relevant content from PDF document '{$pdf_filename}':\n";
                foreach ($relevant_pdf_pages as $page_data) {
                    $context_content .= "Page {$page_data['page_number']} of '{$pdf_filename}': {$page_data['text']}\n";
                }
                $context_content .= "\n";
            }
        }

        // Check for and include Word content
        $word_url = get_transient('mxchat_word_url_' . $session_id);
        $word_embeddings = get_transient('mxchat_word_embeddings_' . $session_id);
        $word_filename = get_transient('mxchat_word_filename_' . $session_id);
        if ($word_url && $word_embeddings && get_transient('mxchat_include_word_in_context_' . $session_id)) {
            $relevant_word_chunks = $this->word_handler->mxchat_find_relevant_word_chunks($user_message_embedding, $word_embeddings);
            if (!empty($relevant_word_chunks)) {
                $context_content .= "Relevant content from Word document '{$word_filename}':\n";
                foreach ($relevant_word_chunks as $chunk_data) {
                    $context_content .= "Section {$chunk_data['chunk_number']} of '{$word_filename}': {$chunk_data['text']}\n";
                }
                $context_content .= "\n";
            }
        }
        
        $context_content = apply_filters('mxchat_prepare_context', $context_content, $session_id);

        // Extract model from current options for bot-specific model support
        $selected_model = isset($current_options['model']) ? $current_options['model'] : 'gpt-5.1-chat-latest';

        // ===== Native function-calling fallback (plan-mxchat-20260617-a41dee) =====
        // Intents already missed (we're past the intent router). If function
        // calling is enabled and the active model is tool-capable, let the model
        // SELECT and run registered callbacks as tools — independent of intents,
        // works with zero Actions. The tool round is buffered; the final answer is
        // emitted via the SAME envelopes the normal path uses. Default-off, so
        // existing installs never enter this branch.
        if ($this->mxchat_fc_should_run($selected_model)) {
            $fc_outcome = $this->mxchat_fc_attempt(
                $message,
                $context_content,
                $conversation_history,
                $selected_model,
                $current_options,
                $session_id,
                $user_id
            );
            if (is_array($fc_outcome) && !empty($fc_outcome['handled'])) {
                $fc_text = isset($fc_outcome['text']) ? $fc_outcome['text'] : '';
                if (!empty($this->current_valid_urls)) {
                    $fc_text = $this->validate_and_clean_urls($fc_text, $this->current_valid_urls, $session_id, $bot_id);
                }
                // plan-mxchat-20260617-48a57a — surface any UI element a tool
                // produced (generated image / product card / image gallery) so the
                // widget RENDERS it, instead of emitting only the model's text.
                // The html was already saved to the transcript in
                // mxchat_fc_execute_tool (or by the callback itself for self-saving
                // core tools), so we persist ONLY the model's caption text here.
                $fc_html = isset($this->fc_ui_html) ? $this->fc_ui_html : '';

                if ($fc_text !== '') {
                    $this->mxchat_save_chat_message($session_id, 'bot', $fc_text, null, null);
                }

                // A video-backed KB source queued during retrieval (03ba33) must
                // surface on the FC path too — the FC envelopes below are the ONLY
                // exit for this turn, so append it to the html channel and persist
                // it (tool html was already saved in mxchat_fc_execute_tool; the
                // video embed has no other save point on this path).
                if (!empty($this->videoEmbedHtml)) {
                    $fc_html .= $this->videoEmbedHtml;
                    $this->mxchat_save_chat_message($session_id, 'bot', $this->videoEmbedHtml);
                }

                if ($is_streaming) {
                    // The frontend SSE reader routes any event carrying text/html
                    // to handleNonStreamResponse(), which renders text + html in a
                    // single bot message — so emit one complete event (mirrors the
                    // intent path's text/html envelope).
                    $sse = array('session_id' => $session_id);
                    if ($fc_text !== '') $sse['text'] = $fc_text;
                    if ($fc_html !== '') $sse['html'] = $fc_html;
                    if ($fc_text === '' && $fc_html === '') $sse['text'] = $this->mxchat_fc_giveup_text();
                    echo "data: " . wp_json_encode($sse) . "\n\n";
                    echo "data: [DONE]\n\n";
                    flush();
                } else {
                    $fc_response_data = array('text' => $fc_text, 'html' => $fc_html, 'session_id' => $session_id);
                    if ($testing_data !== null) {
                        $fc_response_data['testing_data'] = $testing_data;
                    }
                    wp_send_json($fc_response_data);
                }
                wp_die();
            }
        }
        // ===== end function-calling fallback =====

        // Streaming + a queued video embed (03ba33): the provider handlers own the
        // token stream and the [DONE] terminator, so the embed rides a dedicated
        // append_html SSE event emitted BEFORE the stream starts. The client
        // stashes it and appends it as its own bot bubble after [DONE] — old
        // cached widget JS simply ignores the unknown key (no content/text/html/
        // error field, so no branch matches). Transcript save happens after the
        // stream completes, so history order matches the live order (text, then
        // embed).
        if ($is_streaming && !empty($this->videoEmbedHtml)) {
            echo "data: " . wp_json_encode(array(
                'append_html' => $this->videoEmbedHtml,
                'session_id'  => $session_id,
            )) . "\n\n";
            flush();
        }

        $response = $this->mxchat_generate_response(
            $context_content,
            $current_options['api_key'] ?? $this->options['api_key'],
            $current_options['xai_api_key'] ?? $this->options['xai_api_key'],
            $current_options['claude_api_key'] ?? $this->options['claude_api_key'],
            $current_options['deepseek_api_key'] ?? $this->options['deepseek_api_key'],
            $current_options['gemini_api_key'] ?? $this->options['gemini_api_key'],
            $current_options['openrouter_api_key'] ?? $this->options['openrouter_api_key'],
            $conversation_history,
            $is_streaming,
            $session_id,
            $testing_data,
            $selected_model
        );
        
        // Handle streaming vs non-streaming responses
        if ($is_streaming) {
            // Check if streaming actually happened or if it fell back to regular response
            if ($response === true) {
                // Persist the video embed AFTER the provider saved the streamed
                // text, so history replays in the same order the visitor saw
                // (text bubble, then embed bubble). See 03ba33.
                if (!empty($this->videoEmbedHtml)) {
                    $this->mxchat_save_chat_message($session_id, 'bot', $this->videoEmbedHtml);
                }
                wp_die();
            }
            // If we get here, streaming fell back to regular response, continue
            // But if there's an error, we need to send it as SSE format since headers are already set
            if (is_array($response) && isset($response['error'])) {
                $error_message = $response['error'];
                $error_code = $response['error_code'] ?? 'api_error';
                // Send error in SSE format that the client JS can handle
                echo "data: " . json_encode([
                    'error' => true,
                    'error_message' => $error_message,
                    'error_code' => $error_code,
                    'text' => $error_message, // Also include as text for fallback handling
                    'message' => $error_message
                ]) . "\n\n";
                echo "data: [DONE]\n\n";
                flush();
                wp_die();
            }
        }

        // Check if the response is an error array (non-streaming mode)
        if (is_array($response) && isset($response['error'])) {
            wp_send_json_error([
                'error_message' => $response['error'],
                'error_code' => $response['error_code'] ?? 'api_error'
            ]);
            wp_die();
        }
        
        // DEBUG: Check what we have
        //error_log("=== BEFORE URL VALIDATION ===");
        //error_log("current_valid_urls is empty? " . (empty($this->current_valid_urls) ? 'YES' : 'NO'));
        //error_log("current_valid_urls count: " . count($this->current_valid_urls));
        //error_log("current_valid_urls content: " . print_r($this->current_valid_urls, true));
        
        // If we get here, the response is valid text - now validate URLs
        if (!empty($this->current_valid_urls)) {
            //error_log("CALLING validate_and_clean_urls");
            $response = $this->validate_and_clean_urls($response, $this->current_valid_urls, $session_id, $bot_id);
        } else {
            //error_log("SKIPPING validation - current_valid_urls is empty");
        }
        // ===== END URL VALIDATION =====

        // Prepare RAG context data for storage (only include documents used for context)
        $rag_context_for_storage = null;
        $has_rag_data = $this->last_similarity_analysis !== null && !empty($this->last_similarity_analysis['top_matches']);
        $has_action_data = isset($this->last_action_analysis) && !empty($this->last_action_analysis);

        if ($has_rag_data || $has_action_data) {
            $rag_context_for_storage = [];

            // Add RAG/source data if available
            if ($has_rag_data) {
                $rag_context_for_storage['top_matches'] = $this->last_similarity_analysis['top_matches'];
                $rag_context_for_storage['approved_urls'] = $this->current_valid_urls ?? [];
                $rag_context_for_storage['similarity_threshold'] = $this->last_similarity_analysis['threshold_used'] ?? 0.35;
                $rag_context_for_storage['knowledge_base_type'] = $this->last_similarity_analysis['knowledge_base_type'] ?? 'WordPress Database';
                $rag_context_for_storage['total_documents_checked'] = $this->last_similarity_analysis['total_checked'] ?? 0;
                $rag_context_for_storage['sources_used'] = $this->last_similarity_analysis['sources_used'] ?? 0;
                $rag_context_for_storage['total_chunks_used'] = $this->last_similarity_analysis['total_chunks_used'] ?? 0;
            }

            // Add action analysis data if available
            if ($has_action_data) {
                $rag_context_for_storage['action_analysis'] = $this->last_action_analysis;
            }
        }

        // Save the cleaned response with RAG context
        $this->mxchat_save_chat_message($session_id, 'bot', $response, null, $rag_context_for_storage);

        // Step 5: Save additional content if available
        if (!empty($this->productCardHtml)) {
            $this->mxchat_save_chat_message($session_id, 'bot', $this->productCardHtml);
        }

        if (!empty($this->fallbackResponse['html'])) {
            $this->mxchat_save_chat_message($session_id, 'bot', $this->fallbackResponse['html']);
        }

        if (!empty($this->videoEmbedHtml)) {
            $this->mxchat_save_chat_message($session_id, 'bot', $this->videoEmbedHtml);
        }

        // Step 6: Return the response
        // DEBUG: Check if newlines exist in the response
        //error_log("=== MXCHAT NON-STREAMING RESPONSE DEBUG ===");
        //error_log("Response has newlines: " . (strpos($response, "\n") !== false ? 'YES' : 'NO'));
        //error_log("Response first 500 chars: " . substr($response, 0, 500));

        // Product cards and action html keep their existing either/or precedence;
        // a queued video embed (03ba33) is APPENDED so it can coexist with both.
        $additional_html = !empty($this->productCardHtml) ? $this->productCardHtml : ($this->fallbackResponse['html'] ?? '');
        if (!empty($this->videoEmbedHtml)) {
            $additional_html .= $this->videoEmbedHtml;
        }

        $response_data = [
            'text' => $response,
            'html' => $additional_html,
            'session_id' => $session_id
        ];

        // Include vectorstore error info for admin debugging (only visible to admins via testing_data)
        if (!empty($this->last_vectorstore_error) && $testing_data !== null) {
            $testing_data['vectorstore_error'] = $this->last_vectorstore_error;
        }

        // Also pass it as a top-level field so JS can show a better error message to admins
        if (!empty($this->last_vectorstore_error) && current_user_can('manage_options')) {
            $response_data['vectorstore_error'] = $this->last_vectorstore_error;
        }

        // Always add testing data for admins (no toggle needed)
        if ($testing_data !== null) {
            $response_data['testing_data'] = $testing_data;
        }

        wp_send_json($response_data);
        wp_die();
}

/**
 * Get bot-specific options for multi-bot functionality
 * Falls back to default options if bot_id is 'default' or multi-bot add-on is not active
 */
// Also debug the bot options retrieval
private function get_bot_options($bot_id = 'default') {
    //error_log("MXCHAT DEBUG: get_bot_options called for bot: " . $bot_id);

    // The admin Testing tab renders the real widget as bot_id "testing", which
    // is not a registered multi-bot. It must resolve the DEFAULT bot's config
    // so the Testing chat behaves exactly like the front-end (same precedent
    // as the Actions enabled_bots check).
    if ($bot_id === 'testing') {
        $bot_id = 'default';
    }

    if ($bot_id === 'default' || !class_exists('MxChat_Multi_Bot_Manager')) {
        //error_log("MXCHAT DEBUG: Using default options (no multi-bot or bot is 'default')");
        return array();
    }
    
    $bot_options = apply_filters('mxchat_get_bot_options', array(), $bot_id);
    
    if (!empty($bot_options)) {
        //error_log("MXCHAT DEBUG: Got bot-specific options from filter");
        if (isset($bot_options['similarity_threshold'])) {
            //error_log("  - similarity_threshold: " . $bot_options['similarity_threshold']);
        }
    }
    
    return is_array($bot_options) ? $bot_options : array();
}

/**
 * Get bot-specific Pinecone configuration
 * Used in the knowledge retrieval functions
 */
// Also add debugging to your get_bot_pinecone_config function
private function get_bot_pinecone_config($bot_id = 'default') {
    //error_log("MXCHAT DEBUG: get_bot_pinecone_config called for bot: " . $bot_id);

    // Admin Testing tab bot → resolve the DEFAULT bot's backend. Without this,
    // on a multi-bot + Pinecone site the filter below gets an unknown bot id
    // with an EMPTY default, returns array(), and the dispatcher silently
    // searches the WordPress DB while the front-end searches Pinecone — the
    // Testing panel then reports similarity results from a different KB.
    if ($bot_id === 'testing') {
        $bot_id = 'default';
    }

    // If default bot or multi-bot add-on not active, use default Pinecone config
    if ($bot_id === 'default' || !class_exists('MxChat_Multi_Bot_Manager')) {
        //error_log("MXCHAT DEBUG: Using default Pinecone config (no multi-bot or bot is 'default')");
        $addon_options = get_option('mxchat_pinecone_addon_options', array());
        $config = array(
            'use_pinecone' => (isset($addon_options['mxchat_use_pinecone']) && $addon_options['mxchat_use_pinecone'] === '1'),
            'api_key' => $addon_options['mxchat_pinecone_api_key'] ?? '',
            'host' => $addon_options['mxchat_pinecone_host'] ?? '',
            'namespace' => $addon_options['mxchat_pinecone_namespace'] ?? ''
        );
        //error_log("MXCHAT DEBUG: Default config - use_pinecone: " . ($config['use_pinecone'] ? 'true' : 'false'));
        return $config;
    }
    
    //error_log("MXCHAT DEBUG: Calling filter 'mxchat_get_bot_pinecone_config' for bot: " . $bot_id);
    
    // Hook for multi-bot add-on to provide bot-specific Pinecone config
    $bot_pinecone_config = apply_filters('mxchat_get_bot_pinecone_config', array(), $bot_id);
    
    if (!empty($bot_pinecone_config)) {
        //error_log("MXCHAT DEBUG: Got bot-specific config from filter");
        //error_log("  - use_pinecone: " . (isset($bot_pinecone_config['use_pinecone']) ? ($bot_pinecone_config['use_pinecone'] ? 'true' : 'false') : 'not set'));
        //error_log("  - host: " . ($bot_pinecone_config['host'] ?? 'not set'));
        //error_log("  - namespace: " . ($bot_pinecone_config['namespace'] ?? 'not set'));
    } else {
        //error_log("MXCHAT DEBUG: Filter returned empty config!");
    }
    
    return is_array($bot_pinecone_config) ? $bot_pinecone_config : array();
}


// Updated function to check intents and invoke the callback function
private function mxchat_check_intent_and_invoke_callback($message, $user_id, $session_id) {
    global $wpdb;
    $chat_mode = get_option("mxchat_mode_{$session_id}", 'ai');
    
    //  Get the current bot_id
    $current_bot_id = $this->get_current_bot_id($session_id);
    
    // Generate the user embedding
    $user_embedding = $this->mxchat_generate_embedding($message, $this->options['api_key']);

    // Check if embedding generation returned an error
    if (is_array($user_embedding) && isset($user_embedding['error'])) {
        $error_message = $user_embedding['error'];
        $error_code = $user_embedding['error_code'] ?? 'embedding_error';

        // FIXED: Send error in appropriate format based on streaming mode
        if ($this->is_streaming) {
            echo "data: " . json_encode([
                'error' => true,
                'error_message' => $error_message,
                'error_code' => $error_code,
                'text' => $error_message,
                'message' => $error_message
            ]) . "\n\n";
            echo "data: [DONE]\n\n";
            flush();
        } else {
            wp_send_json_error([
                'error_message' => $error_message,
                'error_code' => $error_code
            ]);
        }
        wp_die();
    }

    // Check if embedding is valid
    if (!is_array($user_embedding) || empty($user_embedding)) {
        $error_message = esc_html__('Unable to process your message. The embedding service is not responding correctly.', 'mxchat');

        // FIXED: Send error in appropriate format based on streaming mode
        if ($this->is_streaming) {
            echo "data: " . json_encode([
                'error' => true,
                'error_message' => $error_message,
                'error_code' => 'invalid_embedding',
                'text' => $error_message,
                'message' => $error_message
            ]) . "\n\n";
            echo "data: [DONE]\n\n";
            flush();
        } else {
            wp_send_json_error([
                'error_message' => $error_message,
                'error_code' => 'invalid_embedding'
            ]);
        }
        wp_die();
    }

    // Fetch intents from the database
    $table_name = $wpdb->prefix . 'mxchat_intents';
    if ($chat_mode === 'agent') {
        $query = $wpdb->prepare(
            "SELECT * FROM $table_name WHERE callback_function = %s AND (enabled = 1 OR enabled IS NULL)",
            'mxchat_handle_switch_to_chatbot_intent'
        );
        $intents = $wpdb->get_results($query);
    } else {
        $intents = $wpdb->get_results("SELECT * FROM $table_name WHERE enabled = 1 OR enabled IS NULL");
    }

    if (empty($intents)) {
        return false;
    }

    // Prefetch individual phrase vectors from wp_mxchat_intent_phrases (grouped by intent_id)
    $phrases_table = $wpdb->prefix . 'mxchat_intent_phrases';
    $phrases_by_intent = [];
    if ($wpdb->get_var("SHOW TABLES LIKE '$phrases_table'") === $phrases_table) {
        $all_phrases = $wpdb->get_results("SELECT intent_id, phrase, embedding_vector FROM $phrases_table");
        foreach ($all_phrases as $p) {
            $phrases_by_intent[$p->intent_id][] = $p;
        }
    }

    $highest_similarity = -INF;
    $matched_intent = null;

    //   Array to store action analysis for testing panel
    $action_analysis = [];

    foreach ($intents as $intent) {
        // Additional check for enabled state
        $is_enabled = isset($intent->enabled) ? (bool)$intent->enabled : true;
        if (!$is_enabled) {
            continue;
        }

        //  Check if this action is enabled for the current bot
        if (!$this->is_action_enabled_for_bot($intent, $current_bot_id)) {
            continue;
        }

        $best_similarity = -INF;
        $matched_phrase_text = '';

        // Check legacy embedding vector (existing behavior)
        $intent_embedding_serialized = $intent->embedding_vector;
        $intent_embedding = $intent_embedding_serialized
            ? unserialize($intent_embedding_serialized, ['allowed_classes' => false])
            : null;

        if (is_array($intent_embedding) && !empty($intent_embedding)) {
            $legacy_similarity = $this->mxchat_calculate_cosine_similarity($user_embedding, $intent_embedding);
            if ($legacy_similarity > $best_similarity) {
                $best_similarity = $legacy_similarity;
                $matched_phrase_text = 'legacy';
            }
        }

        // Check individual phrase vectors
        if (isset($phrases_by_intent[$intent->id])) {
            foreach ($phrases_by_intent[$intent->id] as $phrase_row) {
                $phrase_embedding = $phrase_row->embedding_vector
                    ? unserialize($phrase_row->embedding_vector, ['allowed_classes' => false])
                    : null;
                if (!is_array($phrase_embedding)) {
                    continue;
                }
                $phrase_similarity = $this->mxchat_calculate_cosine_similarity($user_embedding, $phrase_embedding);
                if ($phrase_similarity > $best_similarity) {
                    $best_similarity = $phrase_similarity;
                    $matched_phrase_text = $phrase_row->phrase;
                }
            }
        }

        // Skip if no valid embedding was found at all
        if ($best_similarity === -INF) {
            continue;
        }

        $similarity = $best_similarity;
        $intent_threshold = isset($intent->similarity_threshold) ? $intent->similarity_threshold : 0.85;

        //   Store action analysis data for testing panel
        $action_analysis[] = [
            'intent_label' => $intent->intent_label,
            'callback_function' => $intent->callback_function,
            'similarity' => round($similarity, 4),
            'similarity_percentage' => round($similarity * 100, 2),
            'threshold' => $intent_threshold,
            'threshold_percentage' => round($intent_threshold * 100, 2),
            'above_threshold' => $similarity >= $intent_threshold,
            'matched_phrase' => $matched_phrase_text,
            'triggered' => false // Will be updated below if this intent is triggered
        ];

        if ($similarity >= $intent_threshold && $similarity > $highest_similarity) {
            $highest_similarity = $similarity;
            $matched_intent = $intent;
        }
    }
    
    //   Mark the triggered action if any
    if ($matched_intent) {
        foreach ($action_analysis as &$action) {
            if ($action['intent_label'] === $matched_intent->intent_label) {
                $action['triggered'] = true;
                break;
            }
        }
    }
    
    //   Sort actions by similarity (highest first) and store for testing panel
    usort($action_analysis, function($a, $b) {
        return $b['similarity'] <=> $a['similarity'];
    });
    
    // Store action analysis for testing panel capture
    $this->last_action_analysis = $action_analysis;
    
    // Around line 715 in your mxchat_check_intent_and_invoke_callback function
    if ($matched_intent) {
        // If the callback is a method on this instance (core callback), call it directly
        if (method_exists($this, $matched_intent->callback_function)) {
            $callback_result = call_user_func(
                [$this, $matched_intent->callback_function],
                $message,
                $user_id,
                $session_id,
                $matched_intent,
                $user_context ?? null
            );
        } else {
            // Otherwise, use apply_filters for add-on callbacks
            $callback_result = apply_filters(
                $matched_intent->callback_function, 
                false,
                $message, 
                $user_id, 
                $session_id,
                $matched_intent
            );
        }
        
        // Handle the callback result properly
        if ($callback_result !== false) {
            // If callback returned an array with chat_mode, use it directly
            if (is_array($callback_result) && isset($callback_result['chat_mode'])) {
                $this->fallbackResponse = $callback_result;
                return $callback_result; // Return the full array
            } else {
                $this->fallbackResponse = $callback_result;
                return true;
            }
        }
    }
    
    return false;
}

/**
 * Check if an action is enabled for a specific bot
 */
private function is_action_enabled_for_bot($intent, $bot_id) {
    // If enabled_bots column doesn't exist or is null, assume it's enabled for all bots (backward compatibility)
    if (!isset($intent->enabled_bots) || empty($intent->enabled_bots)) {
        return true;
    }

    $enabled_bots = json_decode($intent->enabled_bots, true);

    // If JSON decode fails or returns empty array, assume enabled for all (backward compatibility)
    if (!is_array($enabled_bots) || empty($enabled_bots)) {
        return true;
    }

    // Admin testing tab uses bot_id "testing" — treat it as "default" so all
    // default-bot actions are testable from the admin panel
    if ($bot_id === 'testing') {
        $bot_id = 'default';
    }

    // Check if the current bot is in the enabled bots list
    return in_array($bot_id, $enabled_bots);
}

// Helper function to clear PDF and Word document related transients
private function clear_pdf_transients($session_id) {
    // PDF transients
    delete_transient('mxchat_pdf_url_' . $session_id);
    delete_transient('mxchat_pdf_embeddings_' . $session_id);
    delete_transient('mxchat_include_pdf_in_context_' . $session_id);
    delete_transient('mxchat_waiting_for_pdf_url_' . $session_id);

    // Word document transients
    delete_transient('mxchat_word_url_' . $session_id);
    delete_transient('mxchat_word_filename_' . $session_id);
    delete_transient('mxchat_word_embeddings_' . $session_id);
    delete_transient('mxchat_include_word_in_context_' . $session_id);
    delete_transient('mxchat_waiting_for_word_' . $session_id);
}



//verified good
public function mxchat_handle_email_capture($message, $user_id, $session_id) {
    // Get the user's original instruction/message
    $user_instruction = esc_html($this->options['triggered_phrase_response'] ?? esc_html__("Please provide your email address.", 'mxchat'));
    
    // Set instruction for AI - just pass along what the user wanted to say
    $this->current_action_instruction = $user_instruction;
    
    // Set the transient to track email capture flow
    set_transient('mxchat_email_capture_' . $user_id, true, 5 * MINUTE_IN_SECONDS);
    
    // Return false to let the AI generate the response
    return false;
}

public function mxchat_generate_image($message, $user_id, $session_id) {
    //error_log("Starting image generation for message: " . $message);

    // Prepare a prompt for OpenAI image generation
    $prompt = esc_html__('Create an image of ', 'mxchat') . sanitize_text_field($message);

    // Opt-in routing: when 'custom_provider_for_images' is on, route image gen
    // through the configured Custom (OpenAI-compatible) /images/generations route.
    if (!empty($this->options['custom_provider_for_images']) && $this->options['custom_provider_for_images'] === 'on') {
        $image_response = $this->mxchat_generate_custom_image($prompt);
    } else {
        // Use the existing OpenAI API key
        $openai_api_key = sanitize_text_field($this->options['api_key']);
        // Call OpenAI GPT Image to generate an image
        $image_response = $this->mxchat_generate_openai_image($prompt, $openai_api_key);
    }
    
    // Check if the response contains an image URL
    if (isset($image_response['imageUrl'])) {
        $image_url = esc_url_raw($image_response['imageUrl']);
        
        // Construct the HTML with a CSS class instead of inline styles
        $response_html = '';
        $response_text = esc_html__('Here is the image I generated:', 'mxchat');
        
        // Save the bot message with both text and HTML
        $this->mxchat_save_chat_message($session_id, 'bot', $response_text);
        $this->mxchat_save_chat_message($session_id, 'bot', $response_html);
        
        // Set the fallback response for the chat handler
        $this->fallbackResponse = [
            'text' => $response_text,
            'html' => $response_html,
            'images' => [$image_url]
        ];
        
        // For debugging/verification - Use json_encode to verify what's being set
        //error_log("Image generation successful - fallbackResponse set: " . json_encode($this->fallbackResponse));

        // Return the response directly instead of relying on the property
        return $this->fallbackResponse;
    } else {
        $response_text = esc_html__("I'm sorry, but I couldn't generate an image based on your request.", 'mxchat');
        
        // Save the error message
        $this->mxchat_save_chat_message($session_id, 'bot', $response_text);
        
        // Set the fallback response for the chat handler
        $this->fallbackResponse = [
            'text' => $response_text,
            'html' => '',
            'images' => []
        ];
        
        //error_log("DALL-E image generation error: " . esc_html($image_response['error'] ?? 'Unknown error.'));
        //error_log("Error fallbackResponse set: " . json_encode($this->fallbackResponse));
        
        // Return the response directly instead of relying on the property
        return $this->fallbackResponse;
    }
}

public function mxchat_generate_gemini_image($message, $user_id, $session_id) {
    $prompt = esc_html__('Create an image of ', 'mxchat') . sanitize_text_field($message);

    $gemini_api_key = sanitize_text_field($this->options['gemini_api_key'] ?? '');
    if (empty($gemini_api_key)) {
        $response_text = esc_html__("Gemini API key is not configured.", 'mxchat');
        $this->mxchat_save_chat_message($session_id, 'bot', $response_text);
        return ['text' => $response_text, 'html' => '', 'images' => []];
    }

    $image_response = $this->mxchat_generate_imagen_image($prompt, $gemini_api_key);

    if (isset($image_response['imageUrl'])) {
        $image_url = esc_url_raw($image_response['imageUrl']);

        $response_html = '';
        $response_text = esc_html__('Here is the image I generated:', 'mxchat');

        $this->mxchat_save_chat_message($session_id, 'bot', $response_text);
        $this->mxchat_save_chat_message($session_id, 'bot', $response_html);

        $this->fallbackResponse = [
            'text'   => $response_text,
            'html'   => $response_html,
            'images' => [$image_url]
        ];

        return $this->fallbackResponse;
    } else {
        $response_text = esc_html__("I'm sorry, but I couldn't generate an image based on your request.", 'mxchat');

        $this->mxchat_save_chat_message($session_id, 'bot', $response_text);

        $this->fallbackResponse = [
            'text'   => $response_text,
            'html'   => '',
            'images' => []
        ];

        return $this->fallbackResponse;
    }
}

private function mxchat_save_generated_image($base64_data, $mime_type = 'image/png', $prefix = 'mxchat-generated') {
    // Map the real mime type to a matching file extension so the saved file's
    // extension always agrees with its bytes. A mismatch (e.g. Imagen returning
    // webp bytes that were written into a ".png" file) makes the browser refuse
    // to render the image even though the file saved successfully and the bot
    // reported success — that was the Gemini/Imagen "image never renders" bug.
    // OpenAI + custom-provider paths pass 'image/png' explicitly, so they are
    // unaffected; this only matters for providers that return another type.
    $mime_to_ext = [
        'image/jpeg' => 'jpg',
        'image/jpg'  => 'jpg',
        'image/png'  => 'png',
        'image/webp' => 'webp',
        'image/gif'  => 'gif',
    ];
    $mime_type = strtolower(trim((string) $mime_type));
    if (isset($mime_to_ext[$mime_type])) {
        $extension = $mime_to_ext[$mime_type];
    } else {
        // Unknown/unsupported type: fall back to png and normalize the stored
        // mime so the attachment record and the file extension stay consistent.
        $extension = 'png';
        $mime_type = 'image/png';
    }
    $filename = sanitize_file_name($prefix . '-' . wp_generate_uuid4() . '.' . $extension);
    $decoded = base64_decode($base64_data);

    if ($decoded === false) {
        return new \WP_Error('decode_failed', esc_html__('Failed to decode image data.', 'mxchat'));
    }

    $upload = wp_upload_bits($filename, null, $decoded);

    if (!empty($upload['error'])) {
        return new \WP_Error('upload_failed', $upload['error']);
    }

    $attach_id = wp_insert_attachment([
        'post_mime_type' => $mime_type,
        'post_title'     => $prefix,
        'post_content'   => '',
        'post_status'    => 'inherit',
    ], $upload['file']);

    if (is_wp_error($attach_id)) {
        return $attach_id;
    }

    require_once ABSPATH . 'wp-admin/includes/image.php';
    $metadata = wp_generate_attachment_metadata($attach_id, $upload['file']);
    wp_update_attachment_metadata($attach_id, $metadata);

    return esc_url_raw(wp_get_attachment_url($attach_id));
}

private function mxchat_generate_openai_image($prompt, $api_key, $model = 'gpt-image-1', $timeout = 60) {
    $api_url = 'https://api.openai.com/v1/images/generations';
    $body = json_encode([
        'prompt'        => sanitize_text_field($prompt),
        'n'             => 1,
        'size'          => '1024x1024',
        'quality'       => 'medium',
        'output_format' => 'png',
        'model'         => sanitize_text_field($model),
    ]);

    $args = [
        'body'    => $body,
        'headers' => [
            'Content-Type'  => 'application/json',
            'Authorization' => 'Bearer ' . sanitize_text_field($api_key),
        ],
        'method'  => 'POST',
        'timeout' => absint($timeout),
    ];

    $response = wp_remote_post($api_url, $args);

    if (is_wp_error($response)) {
        return ['error' => esc_html__('Error generating image: ', 'mxchat') . $response->get_error_message()];
    }

    $response_body = json_decode(wp_remote_retrieve_body($response), true);

    $b64 = $response_body['data'][0]['b64_json'] ?? $response_body['data'][0]['b64'] ?? null;
    if ($b64) {
        $saved_url = $this->mxchat_save_generated_image($b64, 'image/png', 'mxchat-openai');
        if (is_wp_error($saved_url)) {
            return ['error' => $saved_url->get_error_message()];
        }
        return ['imageUrl' => $saved_url];
    } else {
        return ['error' => esc_html__('Failed to generate image.', 'mxchat')];
    }
}

/**
 * Generate an image via a Custom (OpenAI-compatible) provider's /images/generations route.
 * Only called when the opt-in 'custom_provider_for_images' setting is on.
 */
private function mxchat_generate_custom_image($prompt, $timeout = 90) {
    $cfg = $this->mxchat_resolve_custom_provider();
    if (empty($cfg['base_url'])) {
        return ['error' => esc_html__('Custom provider Base URL is not configured.', 'mxchat')];
    }
    $url = $cfg['base_url'] . '/images/generations';
    if (!empty($cfg['api_version'])) {
        $url .= (strpos($url, '?') === false ? '?' : '&') . 'api-version=' . rawurlencode($cfg['api_version']);
    }
    $body = wp_json_encode([
        'prompt' => sanitize_text_field($prompt),
        'n'      => 1,
        'size'   => '1024x1024',
        'model'  => $cfg['model'],
    ]);
    $response = wp_remote_post($url, [
        'headers' => $this->mxchat_custom_provider_assoc_headers($cfg),
        'body'    => $body,
        'method'  => 'POST',
        'timeout' => absint($timeout),
    ]);
    if (is_wp_error($response)) {
        return ['error' => esc_html__('Error generating image (custom provider): ', 'mxchat') . $response->get_error_message()];
    }
    $resp = json_decode(wp_remote_retrieve_body($response), true);
    // Try b64 first (matches OpenAI shape), then url-based fallback.
    $b64 = $resp['data'][0]['b64_json'] ?? $resp['data'][0]['b64'] ?? null;
    if ($b64) {
        $saved = $this->mxchat_save_generated_image($b64, 'image/png', 'mxchat-custom');
        if (is_wp_error($saved)) {
            return ['error' => $saved->get_error_message()];
        }
        return ['imageUrl' => $saved];
    }
    $remote_url = $resp['data'][0]['url'] ?? null;
    if ($remote_url) {
        return ['imageUrl' => esc_url_raw($remote_url)];
    }
    $err_msg = $this->extract_provider_error($resp, esc_html__('Custom provider did not return an image.', 'mxchat'));
    return ['error' => esc_html($err_msg)];
}

private function mxchat_generate_imagen_image($prompt, $api_key, $timeout = 60) {
    $api_url = 'https://generativelanguage.googleapis.com/v1beta/models/imagen-4.0-generate-001:predict';

    $body = json_encode([
        'instances'  => [['prompt' => sanitize_text_field($prompt)]],
        'parameters' => [
            'sampleCount' => 1,
            'aspectRatio'  => '1:1',
        ],
    ]);

    $args = [
        'body'    => $body,
        'headers' => [
            'Content-Type'   => 'application/json',
            'x-goog-api-key' => sanitize_text_field($api_key),
        ],
        'method'  => 'POST',
        'timeout' => absint($timeout),
    ];

    $response = wp_remote_post($api_url, $args);

    if (is_wp_error($response)) {
        return ['error' => esc_html__('Error generating image: ', 'mxchat') . $response->get_error_message()];
    }

    $response_body = json_decode(wp_remote_retrieve_body($response), true);

    $b64 = $response_body['predictions'][0]['bytesBase64Encoded'] ?? $response_body['predictions'][0]['imageBytes'] ?? null;
    if ($b64) {
        $mime = $response_body['predictions'][0]['mimeType'] ?? 'image/png';
        $saved_url = $this->mxchat_save_generated_image($b64, $mime, 'mxchat-gemini');
        if (is_wp_error($saved_url)) {
            return ['error' => $saved_url->get_error_message()];
        }
        return ['imageUrl' => $saved_url];
    } else {
        return ['error' => esc_html__('Failed to generate image.', 'mxchat')];
    }
}

/**
 * Handle web search requests.
 *
 * Sends the refined search query to the Brave Search API and uses the
 * results to generate a conversational response with the AI model.
 *
 * @since 1.0.0
 * @param string $message    The user's search query.
 * @param string $user_id    The user identifier.
 * @param string $session_id The current session ID.
 * @return array             Response array containing text with embedded HTML links
 */
public function mxchat_handle_search_request($message, $user_id, $session_id) {
    // Step 1: Interpret and refine the search query
    $refined_search_query = $this->mxchat_interpret_search_query($message);
    if (empty($refined_search_query)) {
        return array(
            'text' => esc_html__('I apologize, but could you please rephrase your search request?', 'mxchat'),
            'html' => ''
        );
    }
    
    // Retrieve and validate API settings
    $options = get_option('mxchat_options');
    $api_key = isset($options['brave_api_key']) ? sanitize_text_field($options['brave_api_key']) : '';
    $results_count = isset($options['brave_results_count']) ? absint($options['brave_results_count']) : 5;
    
    if (empty($api_key)) {
        return array(
            'text' => esc_html__('Search functionality is temporarily unavailable. Please try again later.', 'mxchat'),
            'html' => ''
        );
    }
    
    // Build the API request URL
    $api_url = add_query_arg(
        array(
            'q'                 => rawurlencode($refined_search_query),
            'count'             => $results_count,
            'text_decorations'  => 'true',
            'rich_data'         => 'true',
        ),
        'https://api.search.brave.com/res/v1/web/search'
    );
    
    // Attempt to retrieve cached results first
    $transient_key = 'mxchat_search_' . md5($refined_search_query);
    $results = get_transient($transient_key);
    
    if (false === $results) {
        // SECURITY FIX: Changed to wp_safe_remote_get
        $response = wp_safe_remote_get(
            $api_url,
            array(
                'headers' => array(
                    'Accept'              => 'application/json',
                    'Accept-Encoding'     => 'gzip',
                    'X-Subscription-Token'=> $api_key,
                ),
                'timeout' => 10,
            )
        );
        
        if (is_wp_error($response)) {
            return array(
                'text' => esc_html__('I encountered an error while searching. Please try again.', 'mxchat'),
                'html' => ''
            );
        }
        
        $results = json_decode(wp_remote_retrieve_body($response), true);
        
        if (json_last_error() !== JSON_ERROR_NONE) {
            return array(
                'text' => esc_html__('I received an invalid response from the search service.', 'mxchat'),
                'html' => ''
            );
        }
        
        // Cache results for one hour
        set_transient($transient_key, $results, HOUR_IN_SECONDS);
    }
    
    // Process results
    if (!empty($results['web']['results']) && is_array($results['web']['results'])) {
        // Create a more straightforward summary with HTML links
        $search_results_text = '';
        
        // Add a simple intro
        $search_results_text .= sprintf(
            esc_html__("Here's what I found about '%s':", 'mxchat'),
            esc_html($refined_search_query)
        );
        
        // Add the top results with HTML links
        foreach (array_slice($results['web']['results'], 0, 5) as $result) {
            $title = isset($result['title']) ? wp_strip_all_tags($result['title']) : '';
            $url = isset($result['url']) ? esc_url($result['url']) : '';
            $description = isset($result['description']) ? wp_strip_all_tags($result['description']) : '';
            
            // Add a line break after the intro
            $search_results_text .= '

';
            
            // Add title as a link
            $search_results_text .= sprintf(
                '%s
',
                $url,
                $title
            );
            
            // Add a condensed description
            $search_results_text .= sprintf("%s", $description);
        }
        
        // Save to chat history
        $this->mxchat_save_chat_message($session_id, 'bot', $search_results_text);
        
        // Return the formatted text with embedded HTML links
        return array(
            'text' => $search_results_text,
            'html' => ''
        );
    } else {
        return array(
            'text' => sprintf(
                esc_html__('I searched for "%s" but couldn\'t find any relevant results. Would you like to try different search terms?', 'mxchat'),
                esc_html($refined_search_query)
            ),
            'html' => ''
        );
    }
}

//very good
/**
 * Handle image search requests from the chatbot
 *
 * @param string $message The user's search query
 * @param int $user_id The user's ID
 * @param string $session_id The chat session ID
 * @return array Response array with text and HTML content
 */
public function mxchat_handle_image_search_request($message, $user_id, $session_id) {
    // Step 1: Interpret the search query using the user's selected AI model
    $refined_search_query = $this->mxchat_interpret_search_query($message);

    // If no query was interpreted, return a fallback message
    if (empty($refined_search_query)) {
        return array(
            'text' => __("I'm sorry, I couldn't interpret your search query. Please specify what you'd like to see images of.", 'mxchat'),
            'html' => "",
        );
    }

    // Brave API URL
    $api_url = 'https://api.search.brave.com/res/v1/images/search';

    // Retrieve Brave API settings
    $options = get_option('mxchat_options');
    $api_key = isset($options['brave_api_key']) ? sanitize_text_field($options['brave_api_key']) : '';

    if (empty($api_key)) {
        return array(
            'text' => __("API key is not configured. Please set it in the Brave Search Settings.", 'mxchat'),
            'html' => "",
        );
    }

    $image_count = isset($options['brave_image_count']) ? intval($options['brave_image_count']) : 4;
    $safe_search = isset($options['brave_safe_search']) ? sanitize_text_field($options['brave_safe_search']) : 'strict';

    // Append query parameters based on settings
    $api_url = add_query_arg([
        'q' => rawurlencode($refined_search_query),
        'count' => $image_count,
        'safesearch' => $safe_search,
    ], $api_url);

    // Implement caching
    $transient_key = 'mxchat_image_search_' . md5($refined_search_query);
    $body = get_transient($transient_key);

    if (false === $body) {
        $args = [
            'headers' => [
                'Accept' => 'application/json',
                'Accept-Encoding' => 'gzip',
                'X-Subscription-Token' => $api_key,
            ],
            'timeout' => 10,
        ];

        // SECURITY FIX: Changed to wp_safe_remote_get
        $response = wp_safe_remote_get($api_url, $args);

        if (is_wp_error($response)) {
            return array(
                'text' => __("I'm sorry, I couldn't retrieve any images based on your request.", 'mxchat'),
                'html' => "",
            );
        }

        $body = json_decode(wp_remote_retrieve_body($response), true);
        set_transient($transient_key, $body, HOUR_IN_SECONDS);
    }

    // Process the API response
    if (isset($body['results']) && is_array($body['results']) && count($body['results']) > 0) {
        $html_output = '
';
        
        // Get the configured image count (1-6)
        $display_count = isset($options['brave_image_count']) ? intval($options['brave_image_count']) : 4;
        $display_count = min($display_count, count($body['results'])); // Make sure we don't exceed available images
        
        // Use only the requested number of images
        for ($i = 0; $i < $display_count; $i++) {
            $image = $body['results'][$i];
            $image_url = isset($image['url']) ? esc_url($image['url']) : '';
            $thumbnail_url = isset($image['thumbnail']['src']) ? esc_url($image['thumbnail']['src']) : '';
            $title = isset($image['title']) ? esc_html($image['title']) : esc_html__('Image', 'mxchat');

            if ($image_url && $thumbnail_url) {
                $html_output .= '
';
                $html_output .= '' . $title . '';
                $html_output .= '';
                $html_output .= '';
                $html_output .= '
';
            }
        }

        $html_output .= '
';

        // Create response text
        $response_text = sprintf(__("Here are some images of %s:", 'mxchat'), $refined_search_query);
        
        // Save both response text and HTML to chat history
        $this->mxchat_save_chat_message($session_id, 'bot', $response_text);
        $this->mxchat_save_chat_message($session_id, 'bot', $html_output);

        // Return the combined response
        return array(
            'text' => $response_text,
            'html' => $html_output,
        );
    } else {
        $response_text = __("I'm sorry, I couldn't retrieve any images based on your request.", 'mxchat');
        
        // Save the error message to chat history
        $this->mxchat_save_chat_message($session_id, 'bot', $response_text);
        
        return array(
            'text' => $response_text,
            'html' => "",
        );
    }
}

/**
 * Interpret the search query using the user's selected AI model
 * 
 * @param string $user_query The original query from the user
 * @return string The refined search query
 */
public function mxchat_interpret_search_query($user_query) {
    $system_prompt = esc_html__("Interpret the user's request to provide only the essential keywords or phrases for image searching. Remove conversational language, politeness, or extra context. Return a concise search query that doesn't lose any of the original meaning.", 'mxchat');

    // Get options and determine the selected model
    $options = $this->options ?? get_option('mxchat_options');
    $selected_model = isset($options['model']) ? $options['model'] : 'gpt-5.1-chat-latest';

    // Custom (OpenAI-compatible) provider routes by model id, not prefix.
    if ($selected_model === 'custom-provider') {
        return $this->interpret_query_with_custom($user_query, $system_prompt);
    }

    // Extract model prefix to determine the provider
    $model_parts = explode('-', $selected_model);
    $provider = strtolower($model_parts[0]);

    // Determine which API key to use based on the provider
    switch ($provider) {
        case 'gemini':
            $api_key = isset($options['gemini_api_key']) ? sanitize_text_field($options['gemini_api_key']) : '';
            if (empty($api_key)) {
                return sanitize_text_field($user_query); // Default to original query if API key missing
            }
            return $this->interpret_query_with_gemini($user_query, $system_prompt, $api_key, $selected_model);
            
        case 'claude':
            $api_key = isset($options['claude_api_key']) ? sanitize_text_field($options['claude_api_key']) : '';
            if (empty($api_key)) {
                return sanitize_text_field($user_query);
            }
            return $this->interpret_query_with_claude($user_query, $system_prompt, $api_key, $selected_model);
            
        case 'grok':
            $api_key = isset($options['xai_api_key']) ? sanitize_text_field($options['xai_api_key']) : '';
            if (empty($api_key)) {
                return sanitize_text_field($user_query);
            }
            return $this->interpret_query_with_xai($user_query, $system_prompt, $api_key, $selected_model);
            
        case 'deepseek':
            $api_key = isset($options['deepseek_api_key']) ? sanitize_text_field($options['deepseek_api_key']) : '';
            if (empty($api_key)) {
                return sanitize_text_field($user_query);
            }
            return $this->interpret_query_with_deepseek($user_query, $system_prompt, $api_key, $selected_model);
            
        case 'gpt':
        default:
            // Default to OpenAI for custom models or unrecognized prefixes
            $api_key = isset($options['api_key']) ? sanitize_text_field($options['api_key']) : '';
            if (empty($api_key)) {
                return sanitize_text_field($user_query);
            }
            return $this->interpret_query_with_openai($user_query, $system_prompt, $api_key, $selected_model);
    }
}

/**
 * Interpret query against the configured Custom (OpenAI-compatible) provider.
 * Uses the same base URL + auth scheme as the chat dispatcher.
 */
private function interpret_query_with_custom($user_query, $system_prompt) {
    $cfg = $this->mxchat_resolve_custom_provider();
    if (empty($cfg['base_url'])) {
        return sanitize_text_field($user_query);
    }
    // plan-mxchat-20260715-7124f4: a custom OpenAI-compatible endpoint pointed at
    // a gpt-5-class model rejects temperature!=1 and the legacy max_tokens key.
    // Byte-identical for ordinary custom models (temperature kept, max_tokens
    // used); only gpt-5-class custom models change (best-effort — custom
    // endpoints vary).
    $token_key = $this->mxchat_openai_token_param_for($cfg['model']);
    $payload   = [
        'model'    => $cfg['model'],
        'messages' => [
            ['role' => 'system', 'content' => $system_prompt],
            ['role' => 'user',   'content' => sanitize_text_field($user_query)],
        ],
        $token_key => 20,
    ];
    if ($this->mxchat_openai_supports_temperature_for($cfg['model'])) {
        $payload['temperature'] = 0.2;
    }
    $args = [
        'headers' => $this->mxchat_custom_provider_assoc_headers($cfg),
        'body'    => wp_json_encode($payload),
        'method'  => 'POST',
        'timeout' => 15,
    ];
    $response = wp_remote_post($cfg['chat_url'], $args);
    if (is_wp_error($response)) {
        return sanitize_text_field($user_query);
    }
    $body = json_decode(wp_remote_retrieve_body($response), true);
    return isset($body['choices'][0]['message']['content'])
        ? sanitize_text_field(trim($body['choices'][0]['message']['content']))
        : sanitize_text_field($user_query);
}

/**
 * Convert the colon-style header list returned by mxchat_resolve_custom_provider
 * into the assoc-array form wp_remote_post expects.
 */
private function mxchat_custom_provider_assoc_headers($cfg) {
    $headers = ['Content-Type' => 'application/json'];
    if (!empty($cfg['api_key'])) {
        if (($cfg['auth_scheme'] ?? 'bearer') === 'api-key') {
            $headers['api-key'] = $cfg['api_key'];
        } else {
            $headers['Authorization'] = 'Bearer ' . $cfg['api_key'];
        }
    }
    return $headers;
}

/**
 * Interpret query using OpenAI models
 */
private function interpret_query_with_openai($user_query, $system_prompt, $api_key, $model = 'gpt-5.1-chat-latest') {
    $url = 'https://api.openai.com/v1/chat/completions';
    // plan-mxchat-20260715-7124f4: the default chat model is gpt-5.1-chat-latest
    // and every gpt-5* rejects both a non-default temperature and the legacy
    // max_tokens key (400). This call swallowed the 400 and silently degraded to
    // the raw query on every gpt-5 install, quietly disabling product/image
    // search-query interpretation. Derive capability from the core catalog
    // (dcb71c) so this tracks future model adds; strpos fallback for a
    // partial-upgrade window where the catalog method isn't loaded.
    $token_key = $this->mxchat_openai_token_param_for($model);
    $payload   = [
        'model' => $model,
        'messages' => [
            ['role' => 'system', 'content' => $system_prompt],
            ['role' => 'user', 'content' => sanitize_text_field($user_query)],
        ],
        $token_key => 20,
    ];
    if ($this->mxchat_openai_supports_temperature_for($model)) {
        $payload['temperature'] = 0.2;
    }
    $args = [
        'headers' => [
            'Authorization' => 'Bearer ' . $api_key,
            'Content-Type' => 'application/json',
        ],
        'body' => wp_json_encode($payload),
        'method' => 'POST',
        'timeout' => 15,
    ];

    $response = wp_remote_post($url, $args);
    if (is_wp_error($response)) {
        return sanitize_text_field($user_query);
    }

    $body = json_decode(wp_remote_retrieve_body($response), true);
    return isset($body['choices'][0]['message']['content']) 
        ? sanitize_text_field(trim($body['choices'][0]['message']['content'])) 
        : sanitize_text_field($user_query);
}

/**
 * Anthropic removed temperature/top_p/top_k starting with Opus 4.7 (the API
 * returns 400 if sent) — add new flagship model ids here. (We don't send
 * top_p/top_k in any Claude body, so the list only needs to gate temperature
 * stripping. We never send a `thinking` param either, which is required for
 * claude-fable-5: it rejects an explicit thinking "disabled" — omit only.)
 */
private function mxchat_claude_omits_temperature($model) {
    // plan-mxchat-20260714-dcb71c: derive from the core model catalog (single
    // source of truth). Every caller here passes a Claude model, so
    // !supports_temperature() reproduces the old 4-id in_array() result exactly.
    // Frozen list kept as fallback for a partial-upgrade window where the
    // catalog method isn't loaded.
    if (class_exists('MxChat_Model_Catalog') && method_exists('MxChat_Model_Catalog', 'supports_temperature')) {
        return !MxChat_Model_Catalog::supports_temperature($model);
    }
    $no_temp = array('claude-opus-5', 'claude-opus-4-7', 'claude-opus-4-8', 'claude-fable-5', 'claude-sonnet-5');
    return in_array($model, $no_temp, true);
}

/**
 * plan-mxchat-20260715-7124f4: OpenAI completion-token key for this model,
 * sourced from the core catalog (gpt-5* → max_completion_tokens; else
 * max_tokens). strpos fallback for a partial-upgrade window where the catalog
 * method isn't loaded.
 *
 * @param string $model OpenAI(-compatible) model id.
 * @return string       'max_completion_tokens' | 'max_tokens'
 */
private function mxchat_openai_token_param_for($model) {
    if (class_exists('MxChat_Model_Catalog') && method_exists('MxChat_Model_Catalog', 'openai_token_param')) {
        return MxChat_Model_Catalog::openai_token_param($model);
    }
    return strpos((string) $model, 'gpt-5') === 0 ? 'max_completion_tokens' : 'max_tokens';
}

/**
 * plan-mxchat-20260715-7124f4: whether a NON-default temperature may be sent to
 * this OpenAI(-compatible) model. gpt-5* accept only the default (1) — sending
 * any other value 400s. Sourced from the core catalog; strpos fallback for a
 * partial-upgrade window.
 *
 * @param string $model OpenAI(-compatible) model id.
 * @return bool
 */
private function mxchat_openai_supports_temperature_for($model) {
    if (class_exists('MxChat_Model_Catalog') && method_exists('MxChat_Model_Catalog', 'supports_temperature')) {
        return MxChat_Model_Catalog::supports_temperature($model);
    }
    return strpos((string) $model, 'gpt-5') !== 0;
}

/**
 * plan-mxchat-20260714-dcb71c: per-surface reasoning_effort, sourced from the
 * core model catalog so a model add propagates automatically. The fallback is
 * the frozen pre-dcb71c inline ladder, used only if the catalog method is
 * unavailable (a partial-upgrade window). Byte-identical to the old inline
 * blocks by construction — proven by the dcb71c equivalence harness.
 *
 * @param string $model   Chat model id.
 * @param string $context 'chat' | 'websearch'.
 * @return string|null    Effort to send, or null to omit the param.
 */
private function mxchat_reasoning_effort_for($model, $context) {
    if (class_exists('MxChat_Model_Catalog') && method_exists('MxChat_Model_Catalog', 'reasoning_effort_for')) {
        return MxChat_Model_Catalog::reasoning_effort_for($model, $context);
    }
    return $this->mxchat_reasoning_effort_fallback($model, $context);
}

private function mxchat_reasoning_effort_fallback($model, $context) {
    if (strpos($model, 'gpt-5') !== 0) {
        return null;
    }
    if ($context === 'websearch') {
        $no_reasoning_web = array('gpt-5.2', 'gpt-5.3-chat-latest', 'gpt-5.4-mini', 'gpt-5.4-nano');
        if (in_array($model, $no_reasoning_web, true)) return null;
        if ($model === 'gpt-5.1-2025-11-13') return 'low';
        if ($model === 'gpt-5.5') return 'low';
        if ($model === 'gpt-5.4') return 'low';
        if (in_array($model, array('gpt-5.6-sol', 'gpt-5.6-terra', 'gpt-5.6-luna'), true)) return 'low';
        return null;
    }
    // 'chat'
    $no_reasoning_models = array('gpt-5.2', 'gpt-5.1-chat-latest', 'gpt-5.3-chat-latest', 'gpt-5.4-mini', 'gpt-5.4-nano');
    if (in_array($model, $no_reasoning_models, true)) return null;
    if ($model === 'gpt-5.1-2025-11-13') return 'low';
    if ($model === 'gpt-5.5') return 'none';
    if ($model === 'gpt-5.4') return 'none';
    if (in_array($model, array('gpt-5.6-sol', 'gpt-5.6-terra', 'gpt-5.6-luna'), true)) return 'low';
    return 'minimal';
}

/**
 * Interpret query using Claude models
 */
private function interpret_query_with_claude($user_query, $system_prompt, $api_key, $model) {
    // Anthropic retired claude-opus-4-20250514 / claude-sonnet-4-20250514 on 2026-06-15.
    // Read-time rescue: remap a saved dead ID to the current equivalent before the API call.
    if ($model === 'claude-opus-4-20250514') { $model = 'claude-opus-4-8'; }
    elseif ($model === 'claude-sonnet-4-20250514') { $model = 'claude-sonnet-4-6'; }
    $url = 'https://api.anthropic.com/v1/messages';

    $payload = [
        'model' => $model,
        'system' => $system_prompt,
        'messages' => [
            ['role' => 'user', 'content' => sanitize_text_field($user_query)]
        ],
        'max_tokens' => 20,
        'temperature' => 0.2,
    ];
    if ($this->mxchat_claude_omits_temperature($model)) { unset($payload['temperature']); }

    $args = [
        'headers' => [
            'Content-Type' => 'application/json',
            'x-api-key' => $api_key,
            'anthropic-version' => '2023-06-01',
        ],
        'body' => wp_json_encode($payload),
        'method' => 'POST',
        'timeout' => 15,
    ];

    $response = wp_remote_post($url, $args);
    if (is_wp_error($response)) {
        return sanitize_text_field($user_query);
    }

    $body = json_decode(wp_remote_retrieve_body($response), true);
    // claude-fable-5 prepends a thinking block to content — take the first
    // TEXT block, not content[0].
    foreach ((array) ($body['content'] ?? array()) as $block) {
        if (isset($block['type'], $block['text']) && $block['type'] === 'text' && trim($block['text']) !== '') {
            return sanitize_text_field(trim($block['text']));
        }
    }

    return sanitize_text_field($user_query);
}

/**
 * Interpret query using Gemini models
 */
private function interpret_query_with_gemini($user_query, $system_prompt, $api_key, $model) {
    if ($model === 'gemini-3-pro-preview') {
        $model = 'gemini-3.1-pro-preview';
    }
    // Use v1beta for preview models, v1 for stable models
    $api_version = (strpos($model, 'preview') !== false || strpos($model, 'exp') !== false) ? 'v1beta' : 'v1';

    $url = "https://generativelanguage.googleapis.com/{$api_version}/models/{$model}:generateContent?key=" . urlencode($api_key);
    
    $args = [
        'headers' => [
            'Content-Type' => 'application/json',
        ],
        'body' => wp_json_encode([
            'contents' => [
                [
                    'role' => 'user',
                    'parts' => [
                        ['text' => $system_prompt . "\n\nQuery: " . sanitize_text_field($user_query)]
                    ]
                ]
            ],
            'generationConfig' => [
                'temperature' => 0.2,
                'maxOutputTokens' => 20,
            ],
        ]),
        'method' => 'POST',
        'timeout' => 15,
    ];
    
    $response = wp_remote_post($url, $args);
    if (is_wp_error($response)) {
        return sanitize_text_field($user_query);
    }
    
    $body = json_decode(wp_remote_retrieve_body($response), true);
    if (!empty($body['candidates'][0]['content']['parts'][0]['text'])) {
        return sanitize_text_field(trim($body['candidates'][0]['content']['parts'][0]['text']));
    }
    
    return sanitize_text_field($user_query);
}

/**
 * Interpret query using X.AI (Grok) models
 */
private function interpret_query_with_xai($user_query, $system_prompt, $api_key, $model) {
    $url = 'https://api.xai.com/v1/chat/completions';
    
    $args = [
        'headers' => [
            'Content-Type' => 'application/json',
            'Authorization' => 'Bearer ' . $api_key,
        ],
        'body' => wp_json_encode([
            'model' => $model,
            'messages' => [
                ['role' => 'system', 'content' => $system_prompt],
                ['role' => 'user', 'content' => sanitize_text_field($user_query)],
            ],
            'temperature' => 0.2,
            'max_tokens' => 20,
        ]),
        'method' => 'POST',
        'timeout' => 15,
    ];
    
    $response = wp_remote_post($url, $args);
    if (is_wp_error($response)) {
        return sanitize_text_field($user_query);
    }
    
    $body = json_decode(wp_remote_retrieve_body($response), true);
    if (isset($body['choices'][0]['message']['content'])) {
        return sanitize_text_field(trim($body['choices'][0]['message']['content']));
    }
    
    return sanitize_text_field($user_query);
}

/**
 * Interpret query using DeepSeek models
 */
private function interpret_query_with_deepseek($user_query, $system_prompt, $api_key, $model) {
    $url = 'https://api.deepseek.com/v1/chat/completions';

    $args = [
        'headers' => [
            'Content-Type' => 'application/json',
            'Authorization' => 'Bearer ' . $api_key,
        ],
        'body' => wp_json_encode([
            'model' => $model,
            'messages' => [
                ['role' => 'system', 'content' => $system_prompt],
                ['role' => 'user', 'content' => sanitize_text_field($user_query)],
            ],
            'temperature' => 0.2,
            'max_tokens' => 20,
            // DeepSeek V4 defaults to thinking mode ON (temperature ignored,
            // reasoning burns the 20-token budget); keep the legacy
            // deepseek-chat semantics = non-thinking.
            'thinking' => ['type' => 'disabled'],
        ]),
        'method' => 'POST',
        'timeout' => 15,
    ];
    
    $response = wp_remote_post($url, $args);
    if (is_wp_error($response)) {
        return sanitize_text_field($user_query);
    }
    
    $body = json_decode(wp_remote_retrieve_body($response), true);
    if (isset($body['choices'][0]['message']['content'])) {
        return sanitize_text_field(trim($body['choices'][0]['message']['content']));
    }
    
    return sanitize_text_field($user_query);
}

//very good
private function add_email_to_loops($email) {
    // Sanitize the email
    $email = sanitize_email($email);

    // Retrieve and sanitize options
    $api_key = isset($this->options['loops_api_key']) ? sanitize_text_field($this->options['loops_api_key']) : '';
    $mailing_list_id = isset($this->options['loops_mailing_list']) ? sanitize_text_field($this->options['loops_mailing_list']) : '';

    // Check for missing API key or mailing list ID
    if (empty($api_key) || empty($mailing_list_id)) {
        //error_log(esc_html__('Loops API key or mailing list ID is missing.', 'mxchat'));
        return;
    }

    $data = array(
        'email'        => $email,
        'subscribed'   => true,
        'source'       => __('MxChat AI Chatbot', 'mxchat'),
        'mailingLists' => array($mailing_list_id => true),
    );

    $url = 'https://app.loops.so/api/v1/contacts/create';
    $args = array(
        'body'    => wp_json_encode($data),
        'headers' => array(
            'Authorization' => 'Bearer ' . $api_key,
            'Content-Type'  => 'application/json',
        ),
        'method'  => 'POST',
        'timeout' => 45,
    );

    $response = wp_remote_post($url, $args);

    // Handle errors in the API request
    if (is_wp_error($response)) {
        //error_log(esc_html__('Error adding email to Loops: ', 'mxchat') . $response->get_error_message());
        return;
    }

    // Check for non-200 HTTP responses
    $response_code = wp_remote_retrieve_response_code($response);
    if ($response_code != 200) {
        $response_body = wp_remote_retrieve_body($response);
        //error_log(esc_html__('Loops API responded with code ', 'mxchat') . $response_code . ': ' . $response_body);
    }
}

public function mxchat_handle_pdf_discussion($message, $user_id, $session_id) {
    // Get the maximum number of pages allowed from admin settings
    $max_pages = isset($this->options['pdf_max_pages']) ? intval($this->options['pdf_max_pages']) : 69;

    // Retrieve options for dynamic texts
    $trigger_text = $this->options['pdf_intent_trigger_text'] ?? __("Please provide the URL to the PDF you'd like to discuss.", 'mxchat');
    $success_text = $this->options['pdf_intent_success_text'] ?? __("I've processed the PDF. What questions do you have about it?", 'mxchat');
    $error_text = $this->options['pdf_intent_error_text'] ?? __("Sorry, I couldn't process the PDF. Please ensure it's a valid file.", 'mxchat');

    // Check for explicit request for new PDF
    $new_pdf_requested = stripos($message, 'new') !== false ||
                        stripos($message, 'another') !== false ||
                        stripos($message, 'different') !== false;

    // If user mentions adding/reading a PDF, set waiting flag
    if (stripos($message, 'pdf') !== false ||
        stripos($message, 'document') !== false ||
        stripos($message, 'read') !== false) {
        set_transient('mxchat_waiting_for_pdf_url_' . $session_id, true, HOUR_IN_SECONDS);
        $this->fallbackResponse['text'] = $trigger_text;
        return;
    }

    // If we're waiting for a URL or user requested new PDF
    if ($new_pdf_requested || get_transient('mxchat_waiting_for_pdf_url_' . $session_id)) {
        if (preg_match('/https?:\/\/[^\s"]+/i', $message, $matches)) {
            // Process URL... (rest of your existing URL processing code)
        } else {
            $this->fallbackResponse['text'] = $trigger_text;
        }
        return;
    }

    // Default to proceeding with conversation if no specific PDF action is needed
    $this->fallbackResponse['text'] = '';
}


/**
 * Enhanced fetch_and_split_pdf_pages with SSRF protection
 */
private function fetch_and_split_pdf_pages($pdf_source, $max_pages) {
    // CLEAR DEBUG LOGGING
    //error_log("=== MXCHAT PDF PROCESSING START ===");
    //error_log("PDF Source: " . $pdf_source);
    //error_log("Max Pages: " . $max_pages);
    //error_log("Session ID: " . ($this->session_id ?? 'not set'));
    
    // Check if Advanced Claude Toolbar is available and enabled
    $claude_available = function_exists('mxchatACT_is_advanced_claude_enabled');
    $claude_enabled = $claude_available ? mxchatACT_is_advanced_claude_enabled() : false;
    
    //error_log("Claude Function Available: " . ($claude_available ? 'YES' : 'NO'));
    //error_log("Claude Enabled: " . ($claude_enabled ? 'YES' : 'NO'));
    
    if ($claude_available && $claude_enabled) {
        //error_log("🚀 ATTEMPTING CLAUDE PROCESSING...");
        
        // Attempt Claude processing first
        $claude_result = apply_filters('mxchat_process_pdf_advanced', false, $pdf_source, $max_pages, $this->session_id);
        
        if ($claude_result !== false && is_array($claude_result) && !empty($claude_result)) {
            //error_log("✅ CLAUDE PROCESSING SUCCESSFUL!");
            //error_log("Claude returned " . count($claude_result) . " processed pages");
            
            // Log first page details for verification
            if (isset($claude_result[0])) {
                $first_page = $claude_result[0];
                //error_log("First page enhanced: " . (isset($first_page['enhanced']) && $first_page['enhanced'] ? 'YES' : 'NO'));
                //error_log("Processing method: " . ($first_page['processing_method'] ?? 'not set'));
                //error_log("First page text preview: " . substr($first_page['text'] ?? '', 0, 100) . "...");
            }
            
            //error_log("=== MXCHAT PDF PROCESSING END (CLAUDE) ===");
            return $claude_result;
        } else {
            //error_log("❌ CLAUDE PROCESSING FAILED or returned invalid result");
            //error_log("Claude result type: " . gettype($claude_result));
            if (is_array($claude_result)) {
                //error_log("Claude result count: " . count($claude_result));
            }
        }
    }
    
    // Fallback to basic processing
    //error_log("🔄 FALLING BACK TO BASIC PDF PROCESSING...");
    
    $upload_dir = wp_upload_dir();
    $temp_file = null;
    
    try {
        // Your existing basic processing code here...
        // (I'll include the key parts with debug logging)
        
        if (filter_var($pdf_source, FILTER_VALIDATE_URL)) {
            //error_log("Downloading PDF from URL...");
            
            // SECURITY FIX: Validate URL before processing
            if (!$this->mxchat_is_safe_pdf_url($pdf_source)) {
                //error_log("❌ SECURITY: Blocked unsafe PDF URL");
                return false;
            }
            
            $temp_file = wp_tempnam($pdf_source);
            
            // SECURITY FIX: Changed from wp_remote_get to wp_safe_remote_get
            // Route through the shared MXChat crawler identity (plan bae78f/b6d93c) so
            // every remote-content fetch presents one honest, versioned, filterable,
            // allowlistable User-Agent. function_exists guard keeps the front-end/nopriv
            // path safe if the helper (in the always-loaded main file) is ever unavailable.
            $response = wp_safe_remote_get($pdf_source, [
                'timeout' => 60,
                'headers' => ['User-Agent' => function_exists('mxchat_ingest_user_agent') ? mxchat_ingest_user_agent() : 'MxChat PDF Processor']
            ]);
            
            if (is_wp_error($response) || wp_remote_retrieve_response_code($response) !== 200) {
                $error_message = is_wp_error($response) ? $response->get_error_message() : 'HTTP ' . wp_remote_retrieve_response_code($response);
                //error_log("❌ BASIC PROCESSING: Failed to download PDF: " . $error_message);
                return false;
            }
            
            global $wp_filesystem;
            if (empty($wp_filesystem)) {
                require_once ABSPATH . 'wp-admin/includes/file.php';
                WP_Filesystem();
            }
            $wp_filesystem->put_contents($temp_file, wp_remote_retrieve_body($response), FS_CHMOD_FILE);
            //error_log("✅ PDF downloaded successfully");
        } else {
            $temp_file = $pdf_source;
            //error_log("Using local PDF file: " . $temp_file);
        }
        
        // Parse PDF
        //error_log("Parsing PDF with basic parser...");
        mxchat_load_pdf_parser();
        $parser = new \Smalot\PdfParser\Parser();
        $pdf = $parser->parseFile($temp_file);
        $pages = $pdf->getPages();
        
        //error_log("PDF contains " . count($pages) . " pages");
        
        if (count($pages) > $max_pages) {
            //error_log("❌ BASIC PROCESSING: Too many pages (" . count($pages) . " > " . $max_pages . ")");
            if (filter_var($pdf_source, FILTER_VALIDATE_URL) && $temp_file) {
                unlink($temp_file);
            }
            return 'too_many_pages';
        }
        
        $embeddings = [];
        $processed_pages = 0;
        
        foreach ($pages as $page_number => $page) {
            $text = $page->getText();
            
            if (empty(trim($text))) {
                //error_log("Skipping empty page: " . ($page_number + 1));
                continue;
            }
            
            $text = $this->mxchat_clean_text($text);
            
            $embedding = $this->mxchat_generate_embedding(
                __("Page ", 'mxchat') . ($page_number + 1) . ": " . $text,
                $this->options['api_key']
            );
            
            if ($embedding) {
                $embeddings[] = [
                    'page_number' => $page_number + 1,
                    'embedding' => $embedding,
                    'text' => $text,
                    'enhanced' => false, // CLEARLY MARK AS BASIC
                    'processing_method' => 'basic_pdf_parser'
                ];
                $processed_pages++;
            }
        }
        
        //error_log("✅ BASIC PROCESSING COMPLETE: " . $processed_pages . " pages processed");
        
        // Cleanup
        if (filter_var($pdf_source, FILTER_VALIDATE_URL) && $temp_file && file_exists($temp_file)) {
            unlink($temp_file);
        }
        
        //error_log("=== MXCHAT PDF PROCESSING END (BASIC) ===");
        return $embeddings;
        
    } catch (\Exception $e) {
        //error_log("❌ BASIC PROCESSING ERROR: " . $e->getMessage());
        if (filter_var($pdf_source, FILTER_VALIDATE_URL) && $temp_file && file_exists($temp_file)) {
            unlink($temp_file);
        }
        //error_log("=== MXCHAT PDF PROCESSING END (ERROR) ===");
        return false;
    }
}


/**
 * Validate PDF URL for security
 * Prevents SSRF attacks by blocking dangerous URLs
 */
 
private function mxchat_is_safe_pdf_url($url) {
    // Use WordPress core function for comprehensive validation
    // This blocks localhost, private IPs, and reserved IP ranges
    $validated_url = wp_http_validate_url($url);
    
    if ($validated_url === false) {
        return false;
    }
    
    // Additional check: only allow HTTP/HTTPS schemes
    $parsed = parse_url($url);
    if (!isset($parsed['scheme']) || !in_array($parsed['scheme'], ['http', 'https'], true)) {
        return false;
    }
    
    return true;
}


private function mxchat_clean_text($text) {
    // Remove excessive whitespace
    $text = preg_replace('/\s+/', ' ', $text);
    
    // Remove control characters except newlines and tabs
    $text = preg_replace('/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]/', '', $text);
    
    // Normalize line endings
    $text = str_replace(["\r\n", "\r"], "\n", $text);
    
    // Trim whitespace
    $text = trim($text);
    
    return $text;
}

private function find_relevant_pdf_pages($query_embedding, $embeddings) {
    //error_log(esc_html__("find_relevant_pdf_pages called.", 'mxchat'));

    $most_relevant = null;
    $highest_similarity = -INF;

    foreach ($embeddings as $page_data) {
        $similarity = $this->mxchat_calculate_cosine_similarity($query_embedding, $page_data['embedding']);

        if ($similarity > $highest_similarity) {
            $highest_similarity = $similarity;
            $most_relevant = $page_data['page_number'];
        }
    }

    if (!is_null($most_relevant)) {
        $page_numbers = range(max(1, $most_relevant - 1), min(count($embeddings), $most_relevant + 1));
        return array_filter($embeddings, function ($page) use ($page_numbers) {
            return in_array($page['page_number'], $page_numbers);
        });
    }

    return [];
}


public function handle_pdf_upload() {
    if (!isset($_POST['nonce']) || !MxChat_Integrator::mxchat_verify_chat_send_nonce(wp_unslash((string) $_POST['nonce']))) {
        wp_send_json_error(array('message' => esc_html__('Invalid nonce.', 'mxchat')), 403);
    }

    if (!isset($_FILES['pdf_file']) || !isset($_POST['session_id'])) {
        wp_send_json_error(esc_html__('Missing required parameters.', 'mxchat'));
        return;
    }

    // SECURITY FIX: Check if PDF uploads are enabled in settings
    $options = get_option('mxchat_options', array());
    $show_pdf_button = isset($options['show_pdf_upload_button']) ? $options['show_pdf_upload_button'] : 'on';
    
    if ($show_pdf_button !== 'on') {
        wp_send_json_error(esc_html__('PDF uploads are currently disabled.', 'mxchat'));
        return;
    }

    $file = $_FILES['pdf_file'];
    $session_id = sanitize_text_field($_POST['session_id']);
    $original_filename = sanitize_text_field($file['name']);

    // Update session owner if it changed (e.g. IP changed due to network switch)
    $current_user_identifier = MxChat_User::mxchat_get_user_identifier();
    $session_owner = get_option("mxchat_session_owner_{$session_id}");

    if (!$session_owner || $session_owner !== $current_user_identifier) {
        update_option("mxchat_session_owner_{$session_id}", $current_user_identifier, 'no');
    }

    $file_type = wp_check_filetype($file['name'], ['pdf' => 'application/pdf']);
    if ($file_type['type'] !== 'application/pdf') {
        wp_send_json_error(esc_html__('Invalid file type. Only PDF files are allowed.', 'mxchat'));
        return;
    }

    $upload_dir = wp_upload_dir();
    
    // SECURITY FIX: Generate random filename without exposing session_id
    $random_string = wp_generate_password(20, false, false); // 20 char alphanumeric string
    $pdf_filename = 'mxchat_' . $random_string . '_' . time() . '.pdf';
    $pdf_path = $upload_dir['path'] . '/' . $pdf_filename;

    if (!move_uploaded_file($file['tmp_name'], $pdf_path)) {
        wp_send_json_error(esc_html__('Failed to upload file.', 'mxchat'));
        return;
    }

    $this->clear_pdf_transients($session_id);

    $max_pages = isset($this->options['pdf_max_pages']) ? intval($this->options['pdf_max_pages']) : 69;
    $embeddings = $this->fetch_and_split_pdf_pages($pdf_path, $max_pages);

    if ($embeddings === 'too_many_pages') {
        unlink($pdf_path);
        $error_message = sprintf(
            $this->options['pdf_intent_error_text'] ??
            esc_html__("The provided PDF exceeds the maximum allowed limit of %d pages. Please provide a smaller document.", 'mxchat'),
            $max_pages
        );
        wp_send_json_error($error_message);
        return;
    }

    if ($embeddings === false || empty($embeddings)) {
        unlink($pdf_path);
        $error_message = $this->options['pdf_intent_error_text'] ??
            esc_html__('The uploaded PDF appears to be empty or contains unsupported content.', 'mxchat');
        wp_send_json_error($error_message);
        return;
    }

    if (!empty($embeddings)) {
        // Store the mapping between session and the random filename
        set_transient('mxchat_pdf_url_' . $session_id, $pdf_path, HOUR_IN_SECONDS);
        set_transient('mxchat_pdf_filename_' . $session_id, $original_filename, HOUR_IN_SECONDS);
        set_transient('mxchat_pdf_embeddings_' . $session_id, $embeddings, HOUR_IN_SECONDS);
        set_transient('mxchat_include_pdf_in_context_' . $session_id, true, HOUR_IN_SECONDS);

        $success_message = $this->options['pdf_intent_success_text'] ??
            esc_html__("I've processed the PDF. What questions do you have about it?", 'mxchat');

        wp_send_json_success([
            'message' => $success_message,
            'filename' => $original_filename
        ]);
        return;
    }

    unlink($pdf_path);
    $error_message = $this->options['pdf_intent_error_text'] ??
        esc_html__('Sorry, I couldn\'t process the PDF. Please ensure it\'s a valid file.', 'mxchat');
    wp_send_json_error($error_message);
    return;
}
public function handle_pdf_remove() {
    if (!isset($_POST['nonce']) || !MxChat_Integrator::mxchat_verify_chat_send_nonce(wp_unslash((string) $_POST['nonce']))) {
        wp_send_json_error(array('message' => esc_html__('Invalid nonce.', 'mxchat')), 403);
    }

    if (empty($_POST['session_id'])) {
        wp_send_json_error(esc_html__('Session ID missing.', 'mxchat'));
        wp_die();
    }

    $session_id = sanitize_text_field($_POST['session_id']);
    $pdf_path = get_transient('mxchat_pdf_url_' . $session_id);

    if ($pdf_path && file_exists($pdf_path)) {
        unlink($pdf_path);
    }

    $this->clear_pdf_transients($session_id);

    wp_send_json_success([
        'message' => esc_html__('PDF removed successfully.', 'mxchat')
    ]);
    wp_die();
}


function mxchat_fetch_new_messages() {
    $session_id = sanitize_text_field($_POST['session_id']);
    $last_seen_id = sanitize_text_field($_POST['last_seen_id']);
    $persistence_enabled = $_POST['persistence_enabled'] === 'true';
    $initial_timestamp = isset($_POST['initial_timestamp']) ? intval($_POST['initial_timestamp']) : 0;

    if (empty($session_id)) {
        //error_log(esc_html__('Fetch new messages error: Session ID missing.', 'mxchat'));
        wp_send_json_error(['message' => esc_html__('Session ID missing.', 'mxchat')]);
        wp_die();
    }

    $history = get_option("mxchat_history_{$session_id}", []);

    //error_log("MxChat WhatsApp DEBUG: Fetch new messages for session {$session_id}");
    //error_log("MxChat WhatsApp DEBUG: last_seen_id = " . var_export($last_seen_id, true));
    //error_log("MxChat WhatsApp DEBUG: History count = " . count($history));
    //error_log("MxChat WhatsApp DEBUG: Full history = " . print_r($history, true));

    $new_messages = array_filter($history, function ($message) use ($last_seen_id, $persistence_enabled, $initial_timestamp) {
        //error_log("MxChat WhatsApp DEBUG: Checking message - ID: " . ($message['id'] ?? 'NO_ID') . ", Role: " . ($message['role'] ?? 'NO_ROLE'));

        // If persistence is enabled, show all new messages
        if ($persistence_enabled) {
            $has_id = !empty($message['id']);
            $is_agent = $message['role'] === 'agent';

            // If last_seen_id is empty, 'NaN', or invalid, show all agent messages
            if (empty($last_seen_id) || $last_seen_id === 'NaN' || $last_seen_id === 'undefined') {
                $is_newer = true;
            } else {
                $is_newer = strcmp($message['id'] ?? '', $last_seen_id) > 0;
            }

            //error_log("MxChat WhatsApp DEBUG: has_id={$has_id}, is_newer={$is_newer}, is_agent={$is_agent}");

            return $has_id && $is_newer && $is_agent;
        }

        // If persistence is disabled, only show messages after initial timestamp
        return !empty($message['id']) &&
               $message['role'] === 'agent' &&
               $message['timestamp'] > $initial_timestamp;
    });

    //error_log("MxChat WhatsApp DEBUG: Filtered messages count = " . count($new_messages));

    // Include current chat mode so frontend can detect agent→AI transitions
    $chat_mode = get_option("mxchat_mode_{$session_id}", 'ai');

    wp_send_json_success([
        'new_messages' => array_values($new_messages),
        'chat_mode' => $chat_mode
    ]);
    wp_die();
}
public function mxchat_live_agent_handover($message, $user_id, $session_id) {
    // First check if live agents are available.
    // Outside the SLACK availability schedule this behaves exactly like the
    // manual toggle being off — same away message, same stay-in-AI-mode path
    // (plans 8ccaa2 + 99d7a4: each channel owns its own schedule). The schedule
    // normally stops the tool being offered at all; this is the backstop for
    // any path that calls the handover directly.
    $live_agent_available = $this->options['live_agent_status'] ?? 'off';
    $within_hours = !class_exists('MxChat_Live_Agent_Schedule')
        || MxChat_Live_Agent_Schedule::is_within_hours('slack');
    if ($live_agent_available !== 'on' || !$within_hours) {
        $away_message = $this->options['live_agent_away_message'] ?? 'Sorry, live agents are currently unavailable. I can continue helping you as an AI assistant.';
        $this->fallbackResponse = [
            'text' => $away_message,
            'html' => '',
            'images' => [],
            'chat_mode' => 'ai'
        ];
        wp_send_json([
            'text' => $away_message,
            'html' => '',
            'chat_mode' => 'ai',
            'session_id' => $session_id
        ]);
        wp_die();
    }

    $slack_bot_token = $this->options['live_agent_bot_token'] ?? '';

    if (empty($slack_bot_token)) {
        return false;
    }

    // Check if channel already exists for this session
    $channel_id = get_option("mxchat_channel_{$session_id}", '');

    // Shared-channel mode (plan 9f7756): when a shared handoff channel is
    // configured and this session doesn't already own a per-conversation
    // channel, the handoff posts into the shared channel as a new thread
    // (or into the session's existing thread on a re-handover). Any failure
    // to reach the shared channel falls back to per-conversation creation
    // below, so a misconfigured channel never drops a handoff.
    $shared_channel_setting = trim($this->options['live_agent_shared_channel'] ?? '');
    $shared_thread_ts = get_option("mxchat_thread_{$session_id}", '');
    $use_shared_channel = ($shared_channel_setting !== '' && empty($channel_id));

    if (empty($channel_id) && !$use_shared_channel) {
        $channel_id = $this->mxchat_create_conversation_channel($session_id);
        if (empty($channel_id)) {
            return false; // Failed to create channel
        }
    }

    // Get recent chat history
    $history = get_option("mxchat_history_{$session_id}", []);
    $recent_history = array_slice($history, -5);

    // Format conversation context
    $conversation_context = "";
    if (!empty($recent_history)) {
        $conversation_context = "*Recent Conversation:*\n";
        foreach ($recent_history as $hist_message) {
            $role_display = $hist_message['role'] === 'user' ? 'User' : 'AI';
            $conversation_context .= ">{$role_display}: {$hist_message['content']}\n";
        }
        $conversation_context .= "\n";
    }

    update_option("mxchat_mode_{$session_id}", 'agent');

    // Send message to channel
    $channel_message = "🔔 *New Live Agent Request*\n\n";
    $channel_message .= "*Session ID:* `{$session_id}`\n";
    $channel_message .= "*User ID:* `{$user_id}`\n";

    // Surface the captured visitor identity so the agent knows who they're talking to —
    // guest User IDs are 0, but the pre-chat gate / login / transcript often has name+email (plan-e2195b).
    $visitor = $this->mxchat_get_visitor_identity($session_id);
    if (!empty($visitor['name']) && !empty($visitor['email'])) {
        $channel_message .= "*Visitor:* {$visitor['name']} <{$visitor['email']}>\n";
    } elseif (!empty($visitor['email'])) {
        $channel_message .= "*Visitor:* <{$visitor['email']}>\n";
    } elseif (!empty($visitor['name'])) {
        $channel_message .= "*Visitor:* {$visitor['name']}\n";
    }
    $channel_message .= "\n";

    if (!empty($conversation_context)) {
        $channel_message .= $conversation_context;
    }
    
    $channel_message .= "*Current Message:*\n{$message}\n\n";
    if ($use_shared_channel) {
        $channel_message .= "_Reply in this thread - replies here go to the user. `!endchat` in this thread ends the chat._";
    } else {
        $channel_message .= "_Reply directly in this channel - all messages will go to the user_";
    }

    if ($use_shared_channel) {
        $posted = $this->mxchat_post_shared_handoff($session_id, $channel_message, $shared_thread_ts);
        if (!$posted) {
            // Shared channel unreachable (wrong name/ID, bot not invited,
            // archived...). Fall back to the per-conversation flow so the
            // visitor still reaches an agent; the settings page surfaces the
            // recorded error to the admin.
            $use_shared_channel = false;
            $channel_id = $this->mxchat_create_conversation_channel($session_id);
            if (empty($channel_id)) {
                return false;
            }
            $channel_message = str_replace(
                "_Reply in this thread - replies here go to the user. `!endchat` in this thread ends the chat._",
                "_Reply directly in this channel - all messages will go to the user_",
                $channel_message
            );
        }
    }

    if (!$use_shared_channel) {
        $handoff_post = wp_remote_post('https://slack.com/api/chat.postMessage', [
            'headers' => [
                'Content-Type' => 'application/json',
                'Authorization' => 'Bearer ' . $slack_bot_token
            ],
            'body' => json_encode([
                'channel' => $channel_id,
                'text' => $channel_message,
                'mrkdwn' => true
            ])
        ]);
        // Re-handover edge (plan 7458a7): the stored mxchat_channel_ may point
        // at a channel archived by the auto-archive toggle (or deleted by an
        // admin). Slack answers is_archived / channel_not_found — clear the
        // stale option, mint a fresh channel, and re-post ONCE so the handoff
        // is never silently dropped.
        if (!is_wp_error($handoff_post)) {
            $handoff_data = json_decode(wp_remote_retrieve_body($handoff_post), true);
            $handoff_err  = isset($handoff_data['error']) ? $handoff_data['error'] : '';
            if (isset($handoff_data['ok']) && !$handoff_data['ok'] && in_array($handoff_err, array('is_archived', 'channel_not_found'), true)) {
                delete_option("mxchat_channel_{$session_id}");
                $channel_id = $this->mxchat_create_conversation_channel($session_id);
                if (!empty($channel_id)) {
                    wp_remote_post('https://slack.com/api/chat.postMessage', [
                        'headers' => [
                            'Content-Type' => 'application/json',
                            'Authorization' => 'Bearer ' . $slack_bot_token
                        ],
                        'body' => json_encode([
                            'channel' => $channel_id,
                            'text' => $channel_message,
                            'mrkdwn' => true
                        ])
                    ]);
                }
            }
        }
    }

    $success_message = $this->options['live_agent_notification_message'] ?? 'Live agent has been notified.';
    $this->mxchat_save_chat_message($session_id, 'bot', $success_message);

    $this->fallbackResponse = [
        'text' => $success_message,
        'html' => '',
        'images' => [],
        'chat_mode' => 'agent'
    ];

    wp_send_json([
        'success' => true,
        'text' => $success_message,
        'html' => '',
        'chat_mode' => 'agent',
        'session_id' => $session_id,
        'fallbackResponse' => $this->fallbackResponse
    ]);
    wp_die();
}

/**
 * Archive a session's per-conversation chat- channel after !endchat / session
 * cleanup (plan 7458a7). HARD GUARDS, in order: the toggle must be on
 * (default off = zero change for existing installs); a session with
 * mxchat_thread_ set is a 9f7756 SHARED-channel session and is never
 * archived; only the channel this session owns via mxchat_channel_ is
 * archived, and only when it matches the channel the caller is acting on.
 * Best-effort by design — a failed archive is logged and never blocks the
 * mode flip or cleanup.
 *
 * @param string $session_id
 * @param string $event_channel_id Channel the caller is acting on.
 */
private function mxchat_maybe_archive_conversation_channel($session_id, $event_channel_id) {
    $toggle = $this->options['live_agent_archive_on_end_toggle'] ?? 'off';
    if ($toggle !== 'on') {
        return;
    }
    if (get_option("mxchat_thread_{$session_id}", '') !== '') {
        return; // shared-channel session — the shared channel is NEVER archived
    }
    $owned_channel = get_option("mxchat_channel_{$session_id}", '');
    if ($owned_channel === '' || $owned_channel !== $event_channel_id) {
        return;
    }
    $slack_bot_token = $this->options['live_agent_bot_token'] ?? '';
    if (empty($slack_bot_token)) {
        return;
    }
    $response = wp_remote_post('https://slack.com/api/conversations.archive', [
        'headers' => [
            'Content-Type' => 'application/json',
            'Authorization' => 'Bearer ' . $slack_bot_token
        ],
        'body' => json_encode(['channel' => $owned_channel])
    ]);
    if (is_wp_error($response)) {
        error_log('MxChat: conversations.archive request failed: ' . $response->get_error_message());
        return;
    }
    $data = json_decode(wp_remote_retrieve_body($response), true);
    if (empty($data['ok'])) {
        error_log('MxChat: conversations.archive returned error: ' . (isset($data['error']) ? $data['error'] : 'unknown'));
    }
}

/**
 * Create a dedicated per-conversation Slack channel for a session and invite
 * the configured agents. Extracted from mxchat_live_agent_handover so the
 * shared-channel mode (plan 9f7756) can reuse it as its fallback path.
 *
 * @param string $session_id
 * @return string Channel ID, or '' on failure.
 */
private function mxchat_create_conversation_channel($session_id) {
    $slack_bot_token = $this->options['live_agent_bot_token'] ?? '';
    if (empty($slack_bot_token)) {
        return '';
    }

    $channel_id = '';
    $channel_name = $this->generate_channel_name($session_id);

    $response = wp_remote_post('https://slack.com/api/conversations.create', [
        'headers' => [
            'Content-Type' => 'application/json',
            'Authorization' => 'Bearer ' . $slack_bot_token
        ],
        'body' => json_encode([
            'name' => $channel_name,
            'is_private' => false // Public channel - anyone in workspace can join
        ])
    ]);

    if (!is_wp_error($response)) {
        $response_data = json_decode(wp_remote_retrieve_body($response), true);

        if (isset($response_data['ok']) && $response_data['ok']) {
            $channel_id = $response_data['channel']['id'];
            update_option("mxchat_channel_{$session_id}", $channel_id);

            // Auto-invite agents to the channel
            $agent_user_ids = $this->options['live_agent_user_ids'] ?? '';

            if (!empty($agent_user_ids)) {
                // Parse user IDs (one per line)
                $user_ids = array_filter(array_map('trim', explode("\n", $agent_user_ids)));

                foreach ($user_ids as $user_id_to_invite) {
                    wp_remote_post('https://slack.com/api/conversations.invite', [
                        'headers' => [
                            'Content-Type' => 'application/json',
                            'Authorization' => 'Bearer ' . $slack_bot_token
                        ],
                        'body' => json_encode([
                            'channel' => $channel_id,
                            'users' => $user_id_to_invite
                        ])
                    ]);
                }
            }
        }
    }

    return $channel_id;
}

/**
 * Post a handoff (or a re-handover) into the configured shared channel.
 * First post per session becomes the conversation's thread root; its ts is
 * stored in mxchat_thread_{session} and every later message rides that
 * thread. Records the Slack error for the settings page on failure so the
 * caller can fall back to per-conversation creation.
 *
 * @param string $session_id
 * @param string $text       Fully-built handoff message.
 * @param string $thread_ts  Existing thread root for this session, '' if none.
 * @return bool  True when the message reached the shared channel.
 */
private function mxchat_post_shared_handoff($session_id, $text, $thread_ts = '') {
    $slack_bot_token = $this->options['live_agent_bot_token'] ?? '';
    $configured = trim($this->options['live_agent_shared_channel'] ?? '');
    if (empty($slack_bot_token) || $configured === '') {
        return false;
    }

    // Posting by #name works once the bot is a member; the response carries
    // the real channel ID, cached so the inbound webhook and user-relay
    // don't depend on how the admin wrote the setting.
    $cache = get_option('mxchat_slack_shared_channel_id', array());
    $target = (is_array($cache) && ($cache['configured'] ?? '') === $configured && !empty($cache['id']))
        ? $cache['id']
        : ltrim($configured, '#');

    $body = [
        'channel' => $target,
        'text'    => $text,
        'mrkdwn'  => true
    ];
    if ($thread_ts !== '') {
        $body['thread_ts'] = $thread_ts;
    }

    $response = wp_remote_post('https://slack.com/api/chat.postMessage', [
        'headers' => [
            'Content-Type' => 'application/json',
            'Authorization' => 'Bearer ' . $slack_bot_token
        ],
        'body' => json_encode($body)
    ]);

    if (is_wp_error($response)) {
        update_option('mxchat_slack_shared_channel_error', array(
            'error'      => $response->get_error_message(),
            'configured' => $configured,
            'time'       => time(),
        ), false);
        return false;
    }

    $data = json_decode(wp_remote_retrieve_body($response), true);
    if (empty($data['ok'])) {
        update_option('mxchat_slack_shared_channel_error', array(
            'error'      => $data['error'] ?? 'unknown_error',
            'configured' => $configured,
            'time'       => time(),
        ), false);
        return false;
    }

    delete_option('mxchat_slack_shared_channel_error');

    if (!empty($data['channel'])) {
        update_option('mxchat_slack_shared_channel_id', array(
            'configured' => $configured,
            'id'         => $data['channel'],
        ), false);
    }
    if ($thread_ts === '' && !empty($data['ts'])) {
        update_option("mxchat_thread_{$session_id}", $data['ts'], 'no');
    }

    return true;
}

private function generate_channel_name($session_id) {
    $email = null;
    $name = null;

    // 1. First priority: Check if user is logged in and get their info
    if (is_user_logged_in()) {
        $current_user = wp_get_current_user();
        if (!empty($current_user->user_email)) {
            $email = $current_user->user_email;
            //error_log("[DEBUG] Using logged-in user email for channel: {$email}");
        }
        if (!empty($current_user->display_name)) {
            $name = $current_user->display_name;
            //error_log("[DEBUG] Using logged-in user name for channel: {$name}");
        }
    }
    
    // 2. Second priority: Check for saved email/name from "require email to chat" option
    if (empty($email)) {
        $email_option_key = "mxchat_email_{$session_id}";
        $saved_email = get_option($email_option_key);
        if (!empty($saved_email)) {
            $email = $saved_email;
            //error_log("[DEBUG] Using saved email from session for channel: {$email}");
        }
    }
    
    if (empty($name)) {
        $name_option_key = "mxchat_name_{$session_id}";
        $saved_name = get_option($name_option_key);
        if (!empty($saved_name)) {
            $name = $saved_name;
            //error_log("[DEBUG] Using saved name from session for channel: {$name}");
        }
    }
    
    // 3. Third priority: Check existing chat transcript for email/name
    if (empty($email) || empty($name)) {
        global $wpdb;
        $table_name = $wpdb->prefix . 'mxchat_chat_transcripts';
        $existing_data = $wpdb->get_row($wpdb->prepare(
            "SELECT user_email, user_name FROM $table_name WHERE session_id = %s AND (user_email IS NOT NULL OR user_name IS NOT NULL) LIMIT 1",
            $session_id
        ));
        
        if ($existing_data) {
            if (empty($email) && !empty($existing_data->user_email)) {
                $email = $existing_data->user_email;
                //error_log("[DEBUG] Using email from chat transcript for channel: {$email}");
            }
            if (empty($name) && !empty($existing_data->user_name)) {
                $name = $existing_data->user_name;
                //error_log("[DEBUG] Using name from chat transcript for channel: {$name}");
            }
        }
    }
    
    // 4. Generate channel name based on priority: Name > Email > Session ID
    $channel_name = '';
    
    if (!empty($name)) {
        // Convert name to valid Slack channel name
        $base_name = strtolower(trim($name));
        // Replace spaces and invalid characters
        $base_name = preg_replace('/[^a-z0-9\s]/', '', $base_name);
        $base_name = preg_replace('/\s+/', '-', $base_name);
        $base_name = trim($base_name, '-');
        
        // Get last 4 characters of session ID for uniqueness
        $session_suffix = substr($session_id, -4);
        $channel_name = 'chat-' . $base_name . '-' . strtolower($session_suffix);
        
        // Slack channel names have a 21 character limit
        if (strlen($channel_name) > 21) {
            // Calculate available space for name (21 - 'chat-' - '-' - session_suffix)
            $available_space = 21 - 5 - 1 - strlen($session_suffix); // 'chat-' = 5, '-' = 1
            $truncated_name = substr($base_name, 0, $available_space);
            $truncated_name = rtrim($truncated_name, '-'); // Remove trailing hyphen
            $channel_name = 'chat-' . $truncated_name . '-' . strtolower($session_suffix);
        }
        
        //error_log("[DEBUG] Using name for channel: {$channel_name} (from name: {$name})");
        
    } elseif (!empty($email)) {
        // Convert email to valid Slack channel name (your existing logic)
        $channel_name = 'chat-' . strtolower(str_replace(['@', '.', '+', '_'], ['-at-', '-', '-plus-', '-'], $email));
        // Remove any remaining invalid characters
        $channel_name = preg_replace('/[^a-z0-9\-]/', '', $channel_name);
        // Ensure it doesn't end with a hyphen
        $channel_name = rtrim($channel_name, '-');
        // Slack channel names have a 21 character limit, so truncate if needed
        if (strlen($channel_name) > 21) {
            $channel_name = substr($channel_name, 0, 21);
            $channel_name = rtrim($channel_name, '-'); // Remove trailing hyphen if truncation created one
        }
        
        //error_log("[DEBUG] Using email for channel: {$channel_name} (from email: {$email})");
        
    } else {
        // Fallback to session ID if no name or email found
        $channel_name = 'chat-' . strtolower(preg_replace('/[^a-zA-Z0-9]/', '', $session_id));
        //error_log("[DEBUG] No name or email found, using session ID for channel: {$channel_name}");
    }
    
    // Final validation - ensure channel name meets Slack requirements
    if (strlen($channel_name) > 21) {
        $channel_name = substr($channel_name, 0, 21);
        $channel_name = rtrim($channel_name, '-');
    }
    
    //error_log("[DEBUG] Generated channel name: {$channel_name}");
    return $channel_name;
}

/**
 * Telegram Live Agent Handover
 * Creates a forum topic in the Telegram group and notifies agents
 */
public function mxchat_telegram_live_agent_handover($message, $user_id, $session_id) {
    // Check if Telegram agents are available. Telegram has its OWN availability
    // schedule, independent of Slack's (plan 99d7a4 — each Integrations tab
    // owns its scheduler). Backstop only; the tool is normally withheld
    // off-hours.
    $telegram_available = $this->options['telegram_status'] ?? 'off';
    $within_hours = !class_exists('MxChat_Live_Agent_Schedule')
        || MxChat_Live_Agent_Schedule::is_within_hours('telegram');
    if ($telegram_available !== 'on' || !$within_hours) {
        $away_message = $this->options['telegram_away_message'] ?? 'Sorry, live agents are currently unavailable. I can continue helping you as an AI assistant.';
        $this->fallbackResponse = [
            'text' => $away_message,
            'html' => '',
            'images' => [],
            'chat_mode' => 'ai'
        ];
        wp_send_json([
            'text' => $away_message,
            'html' => '',
            'chat_mode' => 'ai',
            'session_id' => $session_id
        ]);
        wp_die();
    }

    $telegram_bot_token = $this->options['telegram_bot_token'] ?? '';
    $telegram_group_id = $this->options['telegram_group_id'] ?? '';

    if (empty($telegram_bot_token) || empty($telegram_group_id)) {
        return false;
    }

    // Check if topic already exists for this session
    $topic_id = get_option("mxchat_telegram_topic_{$session_id}", '');

    if (empty($topic_id)) {
        // Generate topic name
        $topic_name = $this->generate_telegram_topic_name($session_id);

        // Random icon color (Telegram forum topic colors)
        $icon_colors = [0x6FB9F0, 0xFFD67E, 0xCB86DB, 0x8EEE98, 0xFF93B2, 0xFB6F5F];
        $icon_color = $icon_colors[array_rand($icon_colors)];

        // Create forum topic
        $response = wp_remote_post("https://api.telegram.org/bot{$telegram_bot_token}/createForumTopic", [
            'headers' => ['Content-Type' => 'application/json'],
            'body' => json_encode([
                'chat_id' => $telegram_group_id,
                'name' => $topic_name,
                'icon_color' => $icon_color
            ])
        ]);

        if (!is_wp_error($response)) {
            $response_body = wp_remote_retrieve_body($response);
            $response_data = json_decode($response_body, true);

            if (isset($response_data['ok']) && $response_data['ok']) {
                $topic_id = $response_data['result']['message_thread_id'];
                update_option("mxchat_telegram_topic_{$session_id}", $topic_id);
                update_option("mxchat_telegram_group_{$session_id}", $telegram_group_id);
            }
        }

        if (empty($topic_id)) {
            return false; // Failed to create topic
        }
    }

    // Get recent chat history
    $history = get_option("mxchat_history_{$session_id}", []);
    $recent_history = array_slice($history, -5);

    // Format conversation context for Telegram (HTML format)
    $conversation_context = "";
    if (!empty($recent_history)) {
        $conversation_context = "Recent Conversation:\n";
        foreach ($recent_history as $hist_message) {
            $role_display = $hist_message['role'] === 'user' ? '👤 User' : '🤖 AI';
            $escaped_content = htmlspecialchars($hist_message['content'], ENT_QUOTES, 'UTF-8');
            $conversation_context .= "{$role_display}: {$escaped_content}\n";
        }
        $conversation_context .= "\n";
    }

    // Get user info
    $user_email = get_option("mxchat_email_{$session_id}", 'Not provided');
    $user_name = get_option("mxchat_name_{$session_id}", 'Anonymous');

    // Update session mode
    update_option("mxchat_mode_{$session_id}", 'agent');

    // Send initial message to topic
    $escaped_message = htmlspecialchars($message, ENT_QUOTES, 'UTF-8');
    $topic_message = "🔔 New Live Agent Request\n\n";
    $topic_message .= "Session ID: {$session_id}\n";
    $topic_message .= "User: {$user_name}\n";
    $topic_message .= "Email: {$user_email}\n\n";

    if (!empty($conversation_context)) {
        $topic_message .= $conversation_context;
    }

    $topic_message .= "Current Message:\n{$escaped_message}\n\n";
    $topic_message .= "Reply in this topic - messages will be sent to the user\n";
    $topic_message .= "Type #close, #end, #disconnect, or #done to end the session";

    wp_remote_post("https://api.telegram.org/bot{$telegram_bot_token}/sendMessage", [
        'headers' => ['Content-Type' => 'application/json'],
        'body' => json_encode([
            'chat_id' => $telegram_group_id,
            'message_thread_id' => $topic_id,
            'text' => $topic_message,
            'parse_mode' => 'HTML'
        ])
    ]);

    $success_message = $this->options['telegram_notification_message'] ?? "I've notified a support agent. Please allow a moment for them to respond.";
    $this->mxchat_save_chat_message($session_id, 'bot', $success_message);

    $this->fallbackResponse = [
        'text' => $success_message,
        'html' => '',
        'images' => [],
        'chat_mode' => 'agent'
    ];

    wp_send_json([
        'success' => true,
        'text' => $success_message,
        'html' => '',
        'chat_mode' => 'agent',
        'session_id' => $session_id,
        'fallbackResponse' => $this->fallbackResponse
    ]);
    wp_die();
}

/**
 * Generate topic name for Telegram forum
 */
private function generate_telegram_topic_name($session_id) {
    $name = null;
    $email = null;

    // Check logged in user
    if (is_user_logged_in()) {
        $current_user = wp_get_current_user();
        if (!empty($current_user->display_name)) {
            $name = $current_user->display_name;
        }
        if (!empty($current_user->user_email)) {
            $email = $current_user->user_email;
        }
    }

    // Check session data
    if (empty($name)) {
        $name = get_option("mxchat_name_{$session_id}");
    }
    if (empty($email)) {
        $email = get_option("mxchat_email_{$session_id}");
    }

    // Generate topic name
    $session_suffix = substr($session_id, -6);

    if (!empty($name)) {
        // Clean name for topic (max 128 chars in Telegram)
        $clean_name = preg_replace('/[^\p{L}\p{N}\s\-]/u', '', $name);
        $clean_name = trim($clean_name);
        if (strlen($clean_name) > 50) {
            $clean_name = substr($clean_name, 0, 50);
        }
        return "Chat - {$clean_name} ({$session_suffix})";
    } elseif (!empty($email)) {
        // Use email prefix
        $email_prefix = explode('@', $email)[0];
        if (strlen($email_prefix) > 30) {
            $email_prefix = substr($email_prefix, 0, 30);
        }
        return "Chat - {$email_prefix} ({$session_suffix})";
    }

    return "Chat - {$session_suffix}";
}

/**
 * Send user message to Telegram agent
 */
public function mxchat_send_user_message_to_telegram_agent($message, $user_id, $session_id) {
    $telegram_bot_token = $this->options['telegram_bot_token'] ?? '';
    $topic_id = get_option("mxchat_telegram_topic_{$session_id}", '');
    $group_id = get_option("mxchat_telegram_group_{$session_id}", '');

    if (empty($telegram_bot_token) || empty($topic_id) || empty($group_id)) {
        return false;
    }

    $escaped_message = htmlspecialchars($message, ENT_QUOTES, 'UTF-8');
    $user_message = "👤 User: {$escaped_message}";

    $response = wp_remote_post("https://api.telegram.org/bot{$telegram_bot_token}/sendMessage", [
        'headers' => ['Content-Type' => 'application/json'],
        'body' => json_encode([
            'chat_id' => $group_id,
            'message_thread_id' => $topic_id,
            'text' => $user_message,
            'parse_mode' => 'HTML'
        ])
    ]);

    return !is_wp_error($response);
}

/**
 * Handle incoming Telegram webhook
 */
public function handle_telegram_webhook(WP_REST_Request $request) {
    $body = $request->get_body();
    $data = json_decode($body, true);

    //error_log('[MxChat Telegram DEBUG] Webhook received: ' . $body);

    // Handle message events from forum topics
    if (isset($data['message'])) {
        $message_data = $data['message'];

        // Skip if not from a forum topic
        if (!isset($message_data['message_thread_id'])) {
            //error_log('[MxChat Telegram DEBUG] Skipped: No message_thread_id (not a forum topic message)');
            return new WP_REST_Response(['ok' => true]);
        }

        // Skip bot messages
        if (isset($message_data['from']['is_bot']) && $message_data['from']['is_bot']) {
            //error_log('[MxChat Telegram DEBUG] Skipped: Message from bot');
            return new WP_REST_Response(['ok' => true]);
        }

        $chat_id = $message_data['chat']['id'] ?? '';
        $topic_id = $message_data['message_thread_id'];
        $message_text = $message_data['text'] ?? '';
        $message_id = $message_data['message_id'] ?? '';
        $from = $message_data['from'] ?? [];
        $agent_name = trim(($from['first_name'] ?? '') . ' ' . ($from['last_name'] ?? ''));
        if (empty($agent_name)) {
            $agent_name = $from['username'] ?? 'Agent';
        }

        //error_log("[MxChat Telegram DEBUG] Parsed: chat_id={$chat_id}, topic_id={$topic_id}, agent={$agent_name}, text={$message_text}");

        // Skip empty messages
        if (empty($message_text)) {
            //error_log('[MxChat Telegram DEBUG] Skipped: Empty message text');
            return new WP_REST_Response(['ok' => true]);
        }

        // Find session ID by topic ID - cast to string for comparison
        global $wpdb;
        $topic_id_str = strval($topic_id);
        $session_option = $wpdb->get_var(
            $wpdb->prepare(
                "SELECT option_name FROM {$wpdb->options}
                 WHERE option_name LIKE %s
                 AND option_value = %s",
                'mxchat_telegram_topic_%',
                $topic_id_str
            )
        );

        //error_log("[MxChat Telegram DEBUG] Looking for topic_id={$topic_id_str} in options, found: " . ($session_option ?: 'NULL'));

        if ($session_option) {
            $session_id = str_replace('mxchat_telegram_topic_', '', $session_option);
            //error_log("[MxChat Telegram DEBUG] Session ID: {$session_id}");

            // Verify the group ID matches
            $stored_group_id = get_option("mxchat_telegram_group_{$session_id}", '');
            //error_log("[MxChat Telegram DEBUG] Stored group_id={$stored_group_id}, received chat_id={$chat_id}");

            if (strval($stored_group_id) != strval($chat_id)) {
                //error_log('[MxChat Telegram DEBUG] Skipped: Group ID mismatch');
                return new WP_REST_Response(['ok' => true]);
            }

            // Check for closure commands
            $lower_text = strtolower(trim($message_text));
            if (in_array($lower_text, ['#close', '#end', '#disconnect', '#done'])) {
                //error_log("[MxChat Telegram DEBUG] Closure command received: {$lower_text}");
                // End the live agent session
                update_option("mxchat_mode_{$session_id}", 'ai');

                // Save disconnect message
                $disconnect_message = "Live agent session ended. You're now chatting with the AI assistant.";
                $this->mxchat_save_chat_message($session_id, 'bot', $disconnect_message);

                // Notify in Telegram
                $telegram_bot_token = $this->options['telegram_bot_token'] ?? '';
                if (!empty($telegram_bot_token)) {
                    wp_remote_post("https://api.telegram.org/bot{$telegram_bot_token}/sendMessage", [
                        'headers' => ['Content-Type' => 'application/json'],
                        'body' => json_encode([
                            'chat_id' => $chat_id,
                            'message_thread_id' => $topic_id,
                            'text' => "✅ Session closed. User returned to AI chatbot.",
                            'parse_mode' => 'HTML'
                        ])
                    ]);

                    // Optionally close the topic
                    wp_remote_post("https://api.telegram.org/bot{$telegram_bot_token}/closeForumTopic", [
                        'headers' => ['Content-Type' => 'application/json'],
                        'body' => json_encode([
                            'chat_id' => $chat_id,
                            'message_thread_id' => $topic_id
                        ])
                    ]);
                }

                return new WP_REST_Response(['ok' => true]);
            }

            // Deduplicate messages
            $message_key = md5($session_id . $message_id . $message_text);
            $processed_messages = get_transient('mxchat_telegram_messages_' . $session_id) ?: [];

            if (in_array($message_key, $processed_messages)) {
                //error_log('[MxChat Telegram DEBUG] Skipped: Duplicate message');
                return new WP_REST_Response(['ok' => true]);
            }

            $processed_messages[] = $message_key;
            if (count($processed_messages) > 50) {
                $processed_messages = array_slice($processed_messages, -50);
            }
            set_transient('mxchat_telegram_messages_' . $session_id, $processed_messages, HOUR_IN_SECONDS);

            // Save the agent message - format with agent name prefix for proper parsing
            $formatted_message = "Agent: {$agent_name} - {$message_text}";
            //error_log("[MxChat Telegram DEBUG] Saving agent message: {$formatted_message}");

            $this->mxchat_save_chat_message($session_id, 'agent', $formatted_message);

            // Verify the message was saved to history
            $history = get_option("mxchat_history_{$session_id}", []);
            $last_message = end($history);
            //error_log("[MxChat Telegram DEBUG] History after save - count: " . count($history) . ", last message role: " . ($last_message['role'] ?? 'none'));

            // Send confirmation back to Telegram
            $telegram_bot_token = $this->options['telegram_bot_token'] ?? '';
            if (!empty($telegram_bot_token)) {
                $confirm_key = 'mxchat_telegram_confirm_' . $message_key;
                if (!get_transient($confirm_key)) {
                    wp_remote_post("https://api.telegram.org/bot{$telegram_bot_token}/sendMessage", [
                        'headers' => ['Content-Type' => 'application/json'],
                        'body' => json_encode([
                            'chat_id' => $chat_id,
                            'message_thread_id' => $topic_id,
                            'text' => "✅ Message sent to user",
                            'parse_mode' => 'HTML',
                            'reply_to_message_id' => $message_id
                        ])
                    ]);
                    set_transient($confirm_key, true, 300);
                }
            }
        } else {
            //error_log("[MxChat Telegram DEBUG] No session found for topic_id={$topic_id}");
        }
    } else {
        //error_log('[MxChat Telegram DEBUG] No message in webhook data');
    }

    return new WP_REST_Response(['ok' => true]);
}

public function mxchat_send_user_message_to_agent($message, $user_id, $session_id) {
    // Check if this is a Telegram agent session
    $telegram_topic_id = get_option("mxchat_telegram_topic_{$session_id}", '');
    if (!empty($telegram_topic_id)) {
        return $this->mxchat_send_user_message_to_telegram_agent($message, $user_id, $session_id);
    }

    // Otherwise, try Slack
    $slack_bot_token = $this->options['live_agent_bot_token'] ?? '';

    // Shared-channel session: the conversation lives in a thread of the
    // shared channel (plan 9f7756); relay user messages into that thread.
    $thread_ts = get_option("mxchat_thread_{$session_id}", '');
    if (!empty($thread_ts)) {
        $cache = get_option('mxchat_slack_shared_channel_id', array());
        $channel_id = is_array($cache) ? ($cache['id'] ?? '') : '';
    } else {
        $channel_id = get_option("mxchat_channel_{$session_id}", '');
    }

    if (empty($slack_bot_token) || empty($channel_id)) {
        return false;
    }

    $user_message = "💬 *User:* {$message}";

    $body = [
        'channel' => $channel_id,
        'text' => $user_message,
        'mrkdwn' => true
    ];
    if (!empty($thread_ts)) {
        $body['thread_ts'] = $thread_ts;
    }

    $response = wp_remote_post('https://slack.com/api/chat.postMessage', [
        'headers' => [
            'Content-Type' => 'application/json',
            'Authorization' => 'Bearer ' . $slack_bot_token
        ],
        'body' => json_encode($body)
    ]);

    return !is_wp_error($response);
}
public function handle_slack_interaction(WP_REST_Request $request) {
    //error_log('Received Slack interaction');

    $payload = json_decode($request->get_param('payload'), true);
    //error_log('Payload: ' . print_r($payload, true));

    // Handle button click
    if ($payload['type'] === 'block_actions' && $payload['actions'][0]['action_id'] === 'reply_to_user') {
        $session_id = $payload['actions'][0]['value'];
        $trigger_id = $payload['trigger_id'];

        // Get Bot Token from settings
        $slack_token = $this->options['live_agent_bot_token'] ?? '';

        if (empty($slack_token)) {
            //error_log('Slack Bot Token not configured');
            return new WP_REST_Response(['error' => esc_html__('Bot token not configured', 'mxchat')], 400);
        }
        $response = wp_remote_post('https://slack.com/api/views.open', [
            'headers' => [
                'Content-Type' => 'application/json',
                'Authorization' => 'Bearer ' . $slack_token
            ],
            'body' => json_encode([
                'trigger_id' => $trigger_id,
                'view' => [
                    'type' => 'modal',
                    'callback_id' => 'reply_modal',
                    'title' => [
                        'type' => 'plain_text',
                        'text' => __('Reply to User', 'mxchat')
                    ],
                    'submit' => [
                        'type' => 'plain_text',
                        'text' => __('Send', 'mxchat')
                    ],
                    'close' => [
                        'type' => 'plain_text',
                        'text' => __('Cancel', 'mxchat')
                    ],
                    'blocks' => [
                        [
                            'type' => 'input',
                            'block_id' => 'reply_block',
                            'label' => [
                                'type' => 'plain_text',
                                'text' => sprintf(__('Reply to session: %s', 'mxchat'), $session_id)
                            ],
                            'element' => [
                                'type' => 'plain_text_input',
                                'action_id' => 'message',
                                'multiline' => true,
                                'placeholder' => [
                                    'type' => 'plain_text',
                                    'text' => __('Type your message here...', 'mxchat')
                                ]
                            ]
                        ]
                    ],
                    'private_metadata' => $session_id
                ]
            ])
        ]);

        //error_log('Views.open response: ' . print_r($response, true));

        // Return immediate acknowledgment
        return new WP_REST_Response(['ok' => true]);
    }

    // Handle modal submission
// Handle modal submission
if ($payload['type'] === 'view_submission') {
    $session_id = $payload['view']['private_metadata'];
    $message = $payload['view']['state']['values']['reply_block']['message']['value'];

    // Save the message (keep the message_id but don't include in response)
    $this->mxchat_save_chat_message($session_id, 'agent', $message);

    // Keep the original response format for Slack
    return new WP_REST_Response([
        'response_action' => 'clear'
    ]);
}

    // Default acknowledgment
    return new WP_REST_Response(['ok' => true]);
}
public function mxchat_handle_agent_response(WP_REST_Request $request) {
    //error_log('Received agent response request');
    //error_log('Request data: ' . print_r($request->get_params(), true));
   // //error_log('Raw body: ' . file_get_contents('php://input'));

    // Get the data from Slack's slash command format
    $command_text = $request->get_param('text');
   // //error_log('Command text: ' . $command_text);

    if (empty($command_text)) {
        //error_log(esc_html__('Agent response error: No command text received', 'mxchat'));
        return new WP_REST_Response([
            'error' => esc_html__('Command text is required. Format: /reply session_id message', 'mxchat')
        ], 400);
    }

    // Split the command text into session_id and message
    $parts = explode(' ', $command_text, 2);
    if (count($parts) !== 2) {
        //error_log('Agent response error: Invalid command format');
        return new WP_REST_Response([
            'error' => esc_html__('Invalid format. Use: /reply session_id message', 'mxchat')
        ], 400);
    }

    $session_id = sanitize_text_field($parts[0]);
    $message = sanitize_text_field($parts[1]);

    //error_log("Processing agent response - Session ID: $session_id, Message: $message");

    // Save the message
    $message_id = $this->mxchat_save_chat_message($session_id, 'agent', $message);

    if (!$message_id) {
       // //error_log('Failed to save agent message');
        return new WP_REST_Response([
            'error' => esc_html__('Failed to save message', 'mxchat')
        ], 500);
    }

    // Return success response in Slack's expected format
    return new WP_REST_Response([
        'response_type' => 'in_channel',
        'text' => esc_html__("Message sent successfully to session $session_id", 'mxchat')
    ], 200);
}
public function mxchat_handle_switch_to_chatbot_intent($message, $user_id, $session_id) {
    // Update mode to AI
    update_option("mxchat_mode_{$session_id}", 'ai');
    
    // Clear any existing PDF context to start fresh
    $this->clear_pdf_transients($session_id);
    
    // Set the response with explicit chat_mode
    $this->fallbackResponse = [
        'text' => esc_html__('You are now chatting with the AI chatbot.', 'mxchat'),
        'html' => '',
        'images' => [],
        'chat_mode' => 'ai' // Ensure this is set
    ];
    
    // Return the complete response array instead of just true
    return $this->fallbackResponse;
}

/**
 * Normalize Slack mrkdwn before relaying an agent's message to the web visitor.
 * Slack's Events API auto-wraps URLs as  or , wraps
 * mentions as <@U…>/<#C…|name>, and HTML-escapes &, <, >. Relayed raw, the visitor
 * sees a broken/doubled link with a trailing > (plan-e2195b). Unwrap links FIRST, then
 * unescape entities LAST so extracted URLs (which can contain &) are not corrupted.
 */
private function normalize_slack_text($text) {
    if (!is_string($text) || $text === '') {
        return $text;
    }

    $text = preg_replace_callback('/<([^>|]+)(?:\|([^>]*))?>/', function ($m) {
        $target = $m[1];
        $label  = isset($m[2]) ? $m[2] : '';

        // User/channel mentions: <@U…> or <#C…|name> — prefer the human label, else drop the id.
        if (isset($target[0]) && ($target[0] === '@' || $target[0] === '#')) {
            return $label !== '' ? $label : '';
        }
        // mailto:/tel: — strip the scheme for display.
        if (stripos($target, 'mailto:') === 0) {
            $addr = substr($target, 7);
            return ($label !== '' && $label !== $addr) ? "{$label} ({$addr})" : $addr;
        }
        if (stripos($target, 'tel:') === 0) {
            $num = substr($target, 4);
            return ($label !== '' && $label !== $num) ? "{$label} ({$num})" : $num;
        }
        // Regular URL:  -> "Label (url)"; bare  -> "url".
        if ($label !== '' && $label !== $target) {
            return "{$label} ({$target})";
        }
        return $target;
    }, $text);

    // Entity-unescape LAST (after link extraction) so & inside URLs is repaired too.
    $text = str_replace(array('&', '<', '>'), array('&', '<', '>'), $text);

    return $text;
}

/**
 * Resolve the visitor's name + email for a session, mirroring generate_channel_name()'s
 * priority order: logged-in user, then the pre-chat gate options (mxchat_email_/mxchat_name_),
 * then the chat transcript. Returns ['name' => ..., 'email' => ...] (either may be ''). plan-e2195b.
 */
private function mxchat_get_visitor_identity($session_id) {
    $email = '';
    $name  = '';

    if (is_user_logged_in()) {
        $current_user = wp_get_current_user();
        if (!empty($current_user->user_email))   { $email = $current_user->user_email; }
        if (!empty($current_user->display_name)) { $name  = $current_user->display_name; }
    }

    if (empty($email)) {
        $saved_email = get_option("mxchat_email_{$session_id}", '');
        if (!empty($saved_email)) { $email = $saved_email; }
    }
    if (empty($name)) {
        $saved_name = get_option("mxchat_name_{$session_id}", '');
        if (!empty($saved_name)) { $name = $saved_name; }
    }

    if (empty($email) || empty($name)) {
        global $wpdb;
        $table_name = $wpdb->prefix . 'mxchat_chat_transcripts';
        $existing_data = $wpdb->get_row($wpdb->prepare(
            "SELECT user_email, user_name FROM $table_name WHERE session_id = %s AND (user_email IS NOT NULL OR user_name IS NOT NULL) LIMIT 1",
            $session_id
        ));
        if ($existing_data) {
            if (empty($email) && !empty($existing_data->user_email)) { $email = $existing_data->user_email; }
            if (empty($name)  && !empty($existing_data->user_name))  { $name  = $existing_data->user_name; }
        }
    }

    return array('name' => $name, 'email' => $email);
}

public function handle_slack_messages(WP_REST_Request $request) {
    // Log the incoming request for debugging
    //error_log('Slack events request received: ' . $request->get_body());
    
    $body = $request->get_body();
    $data = json_decode($body, true);
    
    // Handle Slack URL verification
    if (isset($data['type']) && $data['type'] === 'url_verification') {
        //error_log('Slack URL verification challenge: ' . $data['challenge']);
        return new WP_REST_Response($data['challenge'], 200, ['Content-Type' => 'text/plain']);
    }
    
    // IMPORTANT: Handle Slack's event deduplication
    if (isset($data['event_id'])) {
        $event_id = $data['event_id'];
        $processed_events = get_transient('mxchat_slack_events') ?: [];
        
        // Check if we've already processed this event
        if (in_array($event_id, $processed_events)) {
            //error_log("Duplicate event detected: $event_id");
            return new WP_REST_Response(['ok' => true]);
        }
        
        // Add this event to processed list
        $processed_events[] = $event_id;
        // Keep only last 100 events to prevent memory issues
        if (count($processed_events) > 100) {
            $processed_events = array_slice($processed_events, -100);
        }
        // Store for 1 hour
        set_transient('mxchat_slack_events', $processed_events, HOUR_IN_SECONDS);
    }
    
    // Handle message events
    if (isset($data['event']) && $data['event']['type'] === 'message') {
        $event = $data['event'];
        
        // Skip bot messages and messages with subtypes (like bot_message)
        if (isset($event['bot_id']) || isset($event['subtype'])) {
            return new WP_REST_Response(['ok' => true]);
        }
        
        // Threaded replies: in shared-channel mode every conversation lives in
        // a thread rooted at its handoff message — route those to their session
        // by thread root (plan 9f7756). Any other threaded reply (e.g. under a
        // per-conversation channel's confirmation message) finds no session and
        // is skipped, exactly as before.
        if (isset($event['thread_ts']) && $event['thread_ts'] !== $event['ts']) {
            return $this->mxchat_route_shared_thread_reply($event);
        }
        
        $channel_id = $event['channel'];
        $message_text = $event['text'] ?? '';
        $message_ts = $event['ts'] ?? '';

        // Find session ID by looking for matching channel
        global $wpdb;
        $session_option = $wpdb->get_var(
            $wpdb->prepare(
                "SELECT option_name FROM {$wpdb->options}
                 WHERE option_name LIKE 'mxchat_channel_%'
                 AND option_value = %s",
                $channel_id
            )
        );

        if ($session_option) {
            $session_id = str_replace('mxchat_channel_', '', $session_option);

            // Create a unique key for this specific message
            $message_key = md5($session_id . $message_ts . $message_text);
            $processed_messages = get_transient('mxchat_processed_messages_' . $session_id) ?: [];

            // Check if we've already processed this exact message
            if (in_array($message_key, $processed_messages)) {
                //error_log("Duplicate message detected for session $session_id");
                return new WP_REST_Response(['ok' => true]);
            }

            // Add to processed messages
            $processed_messages[] = $message_key;
            // Keep only last 50 messages per session
            if (count($processed_messages) > 50) {
                $processed_messages = array_slice($processed_messages, -50);
            }
            set_transient('mxchat_processed_messages_' . $session_id, $processed_messages, HOUR_IN_SECONDS);

            $slack_bot_token = $this->options['live_agent_bot_token'] ?? '';

            // Handle agent ending the chat — transfer back to AI
            // Format: "!endchat" or "!endchat "
            if (preg_match('/^!endchat\b/i', trim($message_text))) {
                update_option("mxchat_mode_{$session_id}", 'ai');

                // Extract custom message after !endchat, or use empty string
                $custom_message = trim(preg_replace('/^!endchat\s*/i', '', trim($message_text)));

                // Send the agent's custom farewell message if provided
                if (!empty($custom_message)) {
                    $this->mxchat_save_chat_message($session_id, 'agent', $this->normalize_slack_text($custom_message));
                }

                // Confirm in Slack channel
                if (!empty($slack_bot_token)) {
                    wp_remote_post('https://slack.com/api/chat.postMessage', [
                        'headers' => [
                            'Content-Type' => 'application/json',
                            'Authorization' => 'Bearer ' . $slack_bot_token
                        ],
                        'body' => json_encode([
                            'channel' => $channel_id,
                            'text' => "✅ *Chat ended.* User has been transferred back to AI mode.",
                            'mrkdwn' => true
                        ])
                    ]);
                }

                // Auto-archive the ended conversation's channel (plan 7458a7).
                // Toggle-gated, best-effort — never blocks the mode flip.
                $this->mxchat_maybe_archive_conversation_channel($session_id, $channel_id);

                return new WP_REST_Response(['ok' => true]);
            }

            // Save the agent message (normalize Slack link/entity formatting first — plan-e2195b)
            $this->mxchat_save_chat_message($session_id, 'agent', $this->normalize_slack_text($message_text));

            // Send confirmation back to Slack (only once)
            if (!empty($slack_bot_token)) {
                // Use a transient to prevent duplicate confirmations
                $confirm_key = 'mxchat_confirm_' . $message_key;
                if (!get_transient($confirm_key)) {
                    wp_remote_post('https://slack.com/api/chat.postMessage', [
                        'headers' => [
                            'Content-Type' => 'application/json',
                            'Authorization' => 'Bearer ' . $slack_bot_token
                        ],
                        'body' => json_encode([
                            'channel' => $channel_id,
                            'text' => "✅ _Message sent to user_",
                            'thread_ts' => $event['ts'] // Reply in thread
                        ])
                    ]);
                    // Set transient to prevent duplicate confirmations
                    set_transient($confirm_key, true, 300); // 5 minutes
                }
            }
        }
    }
    
    return new WP_REST_Response(['ok' => true]);
}

/**
 * Route an agent's threaded Slack reply to the session whose shared-channel
 * conversation is rooted at that thread (plan 9f7756). Sessions are keyed by
 * the thread root ts stored in mxchat_thread_{session}, so two visitors in
 * the same shared channel can never cross-wire. Unknown threads are ignored.
 *
 * @param array $event Slack message event (has thread_ts !== ts).
 * @return WP_REST_Response
 */
private function mxchat_route_shared_thread_reply($event) {
    $thread_root = $event['thread_ts'] ?? '';
    $message_text = $event['text'] ?? '';
    $message_ts = $event['ts'] ?? '';
    $channel_id = $event['channel'] ?? '';

    if ($thread_root === '') {
        return new WP_REST_Response(['ok' => true]);
    }

    // Find the session owning this thread root (same reverse-lookup shape as
    // the per-conversation channel mapping).
    global $wpdb;
    $session_option = $wpdb->get_var(
        $wpdb->prepare(
            "SELECT option_name FROM {$wpdb->options}
             WHERE option_name LIKE 'mxchat_thread_%'
             AND option_value = %s",
            $thread_root
        )
    );

    if (!$session_option) {
        // Not a shared-channel conversation thread (e.g. a reply under a
        // per-conversation confirmation) — ignore, as before.
        return new WP_REST_Response(['ok' => true]);
    }

    $session_id = str_replace('mxchat_thread_', '', $session_option);

    // Per-message dedupe — same transient pattern as the top-level handler.
    $message_key = md5($session_id . $message_ts . $message_text);
    $processed_messages = get_transient('mxchat_processed_messages_' . $session_id) ?: [];
    if (in_array($message_key, $processed_messages)) {
        return new WP_REST_Response(['ok' => true]);
    }
    $processed_messages[] = $message_key;
    if (count($processed_messages) > 50) {
        $processed_messages = array_slice($processed_messages, -50);
    }
    set_transient('mxchat_processed_messages_' . $session_id, $processed_messages, HOUR_IN_SECONDS);

    $slack_bot_token = $this->options['live_agent_bot_token'] ?? '';

    // Agent ending the chat from inside the thread — same command contract as
    // per-conversation channels: "!endchat" or "!endchat ".
    if (preg_match('/^!endchat\b/i', trim($message_text))) {
        update_option("mxchat_mode_{$session_id}", 'ai');

        $custom_message = trim(preg_replace('/^!endchat\s*/i', '', trim($message_text)));
        if (!empty($custom_message)) {
            $this->mxchat_save_chat_message($session_id, 'agent', $this->normalize_slack_text($custom_message));
        }

        if (!empty($slack_bot_token) && $channel_id !== '') {
            wp_remote_post('https://slack.com/api/chat.postMessage', [
                'headers' => [
                    'Content-Type' => 'application/json',
                    'Authorization' => 'Bearer ' . $slack_bot_token
                ],
                'body' => json_encode([
                    'channel' => $channel_id,
                    'text' => "✅ *Chat ended.* User has been transferred back to AI mode.",
                    'thread_ts' => $thread_root,
                    'mrkdwn' => true
                ])
            ]);
        }

        return new WP_REST_Response(['ok' => true]);
    }

    // Save the agent message for the widget (normalized like the channel path).
    $this->mxchat_save_chat_message($session_id, 'agent', $this->normalize_slack_text($message_text));

    // Confirmation stays inside the conversation's thread.
    if (!empty($slack_bot_token) && $channel_id !== '') {
        $confirm_key = 'mxchat_confirm_' . $message_key;
        if (!get_transient($confirm_key)) {
            wp_remote_post('https://slack.com/api/chat.postMessage', [
                'headers' => [
                    'Content-Type' => 'application/json',
                    'Authorization' => 'Bearer ' . $slack_bot_token
                ],
                'body' => json_encode([
                    'channel' => $channel_id,
                    'text' => "✅ _Message sent to user_",
                    'thread_ts' => $thread_root
                ])
            ]);
            set_transient($confirm_key, true, 300);
        }
    }

    return new WP_REST_Response(['ok' => true]);
}

// For the word upload handler
public function mxchat_handle_word_upload() {
    // Delegate to word handler
    $this->word_handler->mxchat_handle_word_upload();
}

// For the word removal handler
public function mxchat_handle_word_remove() {
    // Delegate to word handler
    $this->word_handler->mxchat_handle_word_remove();
}

// For the word status check
public function mxchat_check_word_status() {
    // Delegate to word handler
    $this->word_handler->mxchat_check_word_status();
}


private function mxchat_get_user_identifier() {
    return MxChat_User::mxchat_get_user_identifier();
}

private function mxchat_generate_embedding($text, $api_key) {
    try {
        // Get options and selected model
        $options = get_option('mxchat_options');
        $selected_model = $options['embedding_model'] ?? 'text-embedding-ada-002';

        // Opt-in: route embeddings through the Custom (OpenAI-compatible) provider.
        // Off by default so existing sites see byte-identical behavior.
        if (!empty($options['custom_provider_for_embeddings']) && $options['custom_provider_for_embeddings'] === 'on') {
            return $this->mxchat_generate_embedding_custom($text);
        }

        // Determine endpoint and API key based on model
        if (strpos($selected_model, 'voyage') === 0) {
            $endpoint = 'https://api.voyageai.com/v1/embeddings';
            $api_key = $options['voyage_api_key'] ?? '';
            
            // Check if Voyage API key is missing
            if (empty($api_key)) {
                //error_log('Voyage API key is missing');
                return [
                    'error' => esc_html__('Voyage AI API key is not configured', 'mxchat'),
                    'error_code' => 'missing_voyage_api_key'
                ];
            }
        } elseif (strpos($selected_model, 'gemini-embedding') === 0) {
            $endpoint = 'https://generativelanguage.googleapis.com/v1beta/models/' . $selected_model . ':embedContent';
            $api_key = $options['gemini_api_key'] ?? '';
            
            // Check if Gemini API key is missing
            if (empty($api_key)) {
                //error_log('Gemini API key is missing');
                return [
                    'error' => esc_html__('Google Gemini API key is not configured', 'mxchat'),
                    'error_code' => 'missing_gemini_api_key'
                ];
            }
        } else {
            $endpoint = 'https://api.openai.com/v1/embeddings';
            // Use the passed API key for OpenAI
            
            // Check if OpenAI API key is missing
            if (empty($api_key)) {
                //error_log('OpenAI API key is missing');
                return [
                    'error' => esc_html__('OpenAI API key is not configured', 'mxchat'),
                    'error_code' => 'missing_openai_api_key'
                ];
            }
        }
        
        // Check if text is empty
        if (empty($text)) {
            //error_log('Empty text provided for embedding generation');
            return [
                'error' => esc_html__('No text provided for embedding generation', 'mxchat'),
                'error_code' => 'empty_embedding_text'
            ];
        }
        
        // Prepare request body based on provider
        if (strpos($selected_model, 'gemini-embedding') === 0) {
            // Gemini API format
            $request_body = [
                'model' => 'models/' . $selected_model,
                'content' => [
                    'parts' => [
                        ['text' => $text]
                    ]
                ],
                'outputDimensionality' => 1536
            ];
            
            // Prepare headers for Gemini (API key as query parameter)
            $endpoint .= '?key=' . $api_key;
            $headers = [
                'Content-Type' => 'application/json'
            ];
        } else {
            // OpenAI/Voyage API format
            $request_body = [
                'input' => $text,
                'model' => $selected_model
            ];
            
            // Add output_dimension for voyage-3-large
            if ($selected_model === 'voyage-3-large') {
                $request_body['output_dimension'] = 2048;
            }
            
            // Prepare headers for OpenAI/Voyage
            $headers = [
                'Content-Type' => 'application/json',
                'Authorization' => 'Bearer ' . $api_key
            ];
        }
        
        // Prepare request arguments
        $args = [
            'body' => wp_json_encode($request_body),
            'headers' => $headers,
            'timeout' => 60,
            'redirection' => 5,
            'blocking' => true,
            'httpversion' => '1.0',
            'sslverify' => true,
        ];
        
        // Make the request
        $response = wp_remote_post($endpoint, $args);
        
        // Handle WordPress errors
        if (is_wp_error($response)) {
            $error_message = $response->get_error_message();
            //error_log('Embedding Generation Error: ' . $error_message);
            return [
                'error' => esc_html__('Connection error when generating embeddings: ', 'mxchat') . esc_html($error_message),
                'error_code' => 'embedding_connection_error'
            ];
        }
        
        // Check HTTP status code
        $status_code = wp_remote_retrieve_response_code($response);
        if ($status_code !== 200) {
            $response_body = json_decode(wp_remote_retrieve_body($response), true);
            
            $error_message = $this->extract_provider_error($response_body, 'HTTP Error ' . $status_code);

            $error_type = isset($response_body['error']['type'])
                ? $response_body['error']['type'] 
                : 'unknown';
                
            //error_log('Embedding API HTTP Error: ' . $status_code . ' - ' . $error_message);
            
            // Handle specific error types
            switch ($error_type) {
                case 'invalid_request_error':
                    if (strpos($error_message, 'API key') !== false) {
                        return [
                            'error' => esc_html__('Invalid API key for embedding generation. Please check your API key configuration.', 'mxchat'),
                            'error_code' => 'embedding_invalid_api_key'
                        ];
                    }
                    break;
                    
                case 'authentication_error':
                    return [
                        'error' => esc_html__('Authentication failed for embedding generation. Please check your API key.', 'mxchat'),
                        'error_code' => 'embedding_auth_error'
                    ];
                    
                case 'rate_limit_exceeded':
                    return [
                        'error' => esc_html__('Rate limit exceeded for embedding generation. Please try again later.', 'mxchat'),
                        'error_code' => 'embedding_rate_limit'
                    ];
                    
                case 'quota_exceeded':
                    return [
                        'error' => esc_html__('API quota exceeded for embedding generation. Please check your billing details.', 'mxchat'),
                        'error_code' => 'embedding_quota_exceeded'
                    ];
            }
            
            // Generic error fallback
            return [
                'error' => esc_html__('Embedding API error - check embedding API key.: ', 'mxchat') . esc_html($error_message),
                'error_code' => 'embedding_api_error',
                'status_code' => $status_code
            ];
        }
        
        $response_body = json_decode(wp_remote_retrieve_body($response), true);
        
        // Handle different response formats based on provider
        if (strpos($selected_model, 'gemini-embedding') === 0) {
            // Gemini API response format
            if (isset($response_body['embedding']['values']) && is_array($response_body['embedding']['values'])) {
                return $response_body['embedding']['values'];
            } else {
                //error_log('Invalid Gemini embedding response: ' . wp_json_encode($response_body));
                return [
                    'error' => esc_html__('Received invalid embedding data from the Gemini API.', 'mxchat'),
                    'error_code' => 'invalid_gemini_embedding_response'
                ];
            }
        } else {
            // OpenAI/Voyage API response format
            if (isset($response_body['data'][0]['embedding']) && is_array($response_body['data'][0]['embedding'])) {
                return $response_body['data'][0]['embedding'];
            } else {
                //error_log('Invalid embedding response: ' . wp_json_encode($response_body));
                return [
                    'error' => esc_html__('Received invalid embedding data from the API.', 'mxchat'),
                    'error_code' => 'invalid_embedding_response'
                ];
            }
        }
    } catch (Exception $e) {
        //error_log('Embedding Exception: ' . $e->getMessage());
        return [
            'error' => esc_html__('System error when generating embeddings: ', 'mxchat') . esc_html($e->getMessage()),
            'error_code' => 'embedding_exception'
        ];
    }
}


/**
 * Generate embedding via a Custom (OpenAI-compatible) provider's /embeddings route.
 * Only called when the opt-in 'custom_provider_for_embeddings' setting is on.
 * Returns a numeric array (the embedding vector) on success, or ['error','error_code'] on failure.
 */
private function mxchat_generate_embedding_custom($text) {
    if (empty($text)) {
        return ['error' => esc_html__('No text provided for embedding generation', 'mxchat'), 'error_code' => 'empty_embedding_text'];
    }
    $cfg = $this->mxchat_resolve_custom_provider();
    if (empty($cfg['base_url'])) {
        return ['error' => esc_html__('Custom provider Base URL is not configured.', 'mxchat'), 'error_code' => 'missing_custom_provider_base_url'];
    }

    $options    = get_option('mxchat_options');
    $embed_url  = $cfg['base_url'] . '/embeddings';
    if (!empty($cfg['api_version'])) {
        $embed_url .= (strpos($embed_url, '?') === false ? '?' : '&') . 'api-version=' . rawurlencode($cfg['api_version']);
    }
    $model = isset($options['custom_provider_embedding_model']) && trim((string) $options['custom_provider_embedding_model']) !== ''
        ? trim((string) $options['custom_provider_embedding_model'])
        : $cfg['model'];

    $response = wp_remote_post($embed_url, [
        'headers' => $this->mxchat_custom_provider_assoc_headers($cfg),
        'body'    => wp_json_encode(['input' => $text, 'model' => $model]),
        'timeout' => 60,
    ]);
    if (is_wp_error($response)) {
        return [
            'error' => esc_html__('Connection error when generating embeddings (custom provider): ', 'mxchat') . esc_html($response->get_error_message()),
            'error_code' => 'embedding_custom_connection_error',
        ];
    }
    $status = wp_remote_retrieve_response_code($response);
    $body   = json_decode(wp_remote_retrieve_body($response), true);
    if ($status !== 200) {
        $msg = $this->extract_provider_error($body, 'HTTP ' . $status);
        return [
            'error' => esc_html__('Custom embedding endpoint error: ', 'mxchat') . esc_html($msg),
            'error_code' => 'embedding_custom_api_error',
            'status_code' => $status,
        ];
    }
    if (isset($body['data'][0]['embedding']) && is_array($body['data'][0]['embedding'])) {
        return $body['data'][0]['embedding'];
    }
    return [
        'error' => esc_html__('Invalid embedding response from custom provider.', 'mxchat'),
        'error_code' => 'embedding_custom_invalid_response',
    ];
}

private function mxchat_find_relevant_content($user_embedding, $bot_id = 'default', $user_query = '') {
    //error_log("MXCHAT DEBUG: find_relevant_content called with bot_id: " . $bot_id);

    // Check for OpenAI Vector Store first (takes priority when enabled)
    $bot_vectorstore_config = $this->get_bot_vectorstore_config($bot_id);

    if ($bot_vectorstore_config['use_vectorstore']) {
        // Get current model to verify it's an OpenAI model
        $bot_options = $this->get_bot_options($bot_id);
        $mxchat_options = get_option('mxchat_options', array());
        $current_options = !empty($bot_options) ? $bot_options : $mxchat_options;
        $selected_model = $current_options['model'] ?? 'gpt-5.1-chat-latest';

        if ($this->is_openai_chat_model($selected_model)) {
            //error_log("MXCHAT DEBUG: Using OpenAI Vector Store for knowledge retrieval");
            return $this->find_relevant_content_openai_vectorstore($user_query, $bot_id, $bot_vectorstore_config);
        } else {
            //error_log("MXCHAT DEBUG: Vector Store enabled but model is not OpenAI (" . $selected_model . "), skipping Vector Store");
        }
    }

    // Get bot-specific Pinecone configuration
    $bot_pinecone_config = $this->get_bot_pinecone_config($bot_id);

    // Debug: Log the Pinecone configuration
    //error_log("MXCHAT DEBUG: Pinecone config for bot '$bot_id':");
    //error_log("  - use_pinecone: " . ($bot_pinecone_config['use_pinecone'] ? 'true' : 'false'));
    //error_log("  - api_key: " . (empty($bot_pinecone_config['api_key']) ? 'EMPTY' : 'SET (hidden)'));
    //error_log("  - host: " . ($bot_pinecone_config['host'] ?? 'NOT SET'));
    //error_log("  - namespace: " . ($bot_pinecone_config['namespace'] ?? 'NOT SET'));

    // Determine whether to use Pinecone based on bot configuration
    $use_pinecone = isset($bot_pinecone_config['use_pinecone']) ? $bot_pinecone_config['use_pinecone'] : false;

    //error_log("MXCHAT DEBUG: Using " . ($use_pinecone ? "Pinecone" : "WordPress Database") . " for knowledge retrieval");

    if ($use_pinecone) {
        return $this->find_relevant_content_pinecone($user_embedding, $bot_id, $bot_pinecone_config);
    } else {
        return $this->find_relevant_content_wordpress($user_embedding, $bot_id);
    }
}

private function find_relevant_content_wordpress($user_embedding, $bot_id = 'default') {
    global $wpdb;
    $system_prompt_table = $wpdb->prefix . 'mxchat_system_prompt_content';
    // Initialize similarity analysis storage
    $this->last_similarity_analysis = [
        'knowledge_base_type' => 'WordPress Database',
        'bot_id' => $bot_id,
        'top_matches' => [],
        'threshold_used' => 0,
        'total_checked' => 0
    ];

    // NEW: Initialize valid URLs array
    $valid_urls = [];

    // Get bot-specific options for similarity threshold
    $bot_options = $this->get_bot_options($bot_id);
    $current_options = !empty($bot_options) ? $bot_options : $this->options;

    // Get knowledge manager instance for role checking
    $knowledge_manager = MxChat_Knowledge_Manager::get_instance();

    // Get base similarity threshold from bot options or default options
    $similarity_threshold = isset($current_options['similarity_threshold'])
        ? ((int) $current_options['similarity_threshold']) / 100
        : 0.35;
    $this->last_similarity_analysis['threshold_used'] = $similarity_threshold;

    // Precompute bot_filter once, outside the streaming loop
    $bot_filter = '';
    if ($bot_id !== 'default') {
        $column_exists = $wpdb->get_var("SHOW COLUMNS FROM {$system_prompt_table} LIKE 'bot_metadata'");
        if ($column_exists) {
            $bot_filter = $wpdb->prepare(" AND (bot_metadata = %s OR bot_metadata IS NULL OR bot_metadata = '')", $bot_id);
        }
    }

    // ===== STREAMING TOP-K PASS =====
    // Stream rows in small batches, compute cosine similarity per row, and keep only:
    //   - top 10 by raw similarity (for the testing/debug display panel)
    //   - candidates above threshold with access (capped) for context assembly
    // This bounds peak memory regardless of knowledge base size and avoids loading
    // article_content for every row. article_content is fetched in Phase 2 for winners only.
    $batch_size = 250;
    $max_candidates = 200; // safety cap, well above rag_sources_limit * max_chunks_per_source
    $top_display = [];
    $candidates = [];
    $total_checked = 0;
    $offset = 0;

    do {
        $batch = $wpdb->get_results($wpdb->prepare(
            "SELECT id, embedding_vector, source_url, role_restriction
             FROM {$system_prompt_table}
             WHERE 1=1 {$bot_filter}
             LIMIT %d OFFSET %d",
            $batch_size,
            $offset
        ));

        if (empty($batch)) {
            break;
        }

        foreach ($batch as $row) {
            $database_embedding = $row->embedding_vector
                ? unserialize($row->embedding_vector, ['allowed_classes' => false])
                : null;

            if (!is_array($database_embedding) || !is_array($user_embedding)) {
                unset($database_embedding);
                continue;
            }

            $similarity = $this->mxchat_calculate_cosine_similarity($user_embedding, $database_embedding);
            unset($database_embedding);

            $role_restriction = $row->role_restriction ?? 'public';
            $has_access = $knowledge_manager->mxchat_user_has_content_access($role_restriction);
            $source_url = $row->source_url ?? '';

            // Maintain top 10 display buffer (insert-if-beats-worst)
            if (count($top_display) < 10) {
                $top_display[] = [
                    'id' => $row->id,
                    'similarity' => $similarity,
                    'source_url' => $source_url,
                    'role_restriction' => $role_restriction,
                    'has_access' => $has_access,
                ];
                usort($top_display, function ($a, $b) {
                    return $b['similarity'] <=> $a['similarity'];
                });
            } elseif ($similarity > $top_display[9]['similarity']) {
                $top_display[9] = [
                    'id' => $row->id,
                    'similarity' => $similarity,
                    'source_url' => $source_url,
                    'role_restriction' => $role_restriction,
                    'has_access' => $has_access,
                ];
                usort($top_display, function ($a, $b) {
                    return $b['similarity'] <=> $a['similarity'];
                });
            }

            // Track candidates for context assembly (above threshold + has access)
            if ($similarity >= $similarity_threshold && $has_access) {
                $candidates[] = [
                    'id' => $row->id,
                    'similarity' => $similarity,
                    'source_url' => $source_url,
                ];
            }

            $total_checked++;
        }

        unset($batch);

        // Trim candidates periodically to cap memory during long scans
        if (count($candidates) > $max_candidates) {
            usort($candidates, function ($a, $b) {
                return $b['similarity'] <=> $a['similarity'];
            });
            $candidates = array_slice($candidates, 0, $max_candidates);
        }

        $offset += $batch_size;
    } while (true);

    if ($total_checked === 0) {
        $this->current_valid_urls = [];
        return '';
    }

    // Final candidates sort (best first)
    if (count($candidates) > 1) {
        usort($candidates, function ($a, $b) {
            return $b['similarity'] <=> $a['similarity'];
        });
    }

    // ===== PHASE 2: FETCH ARTICLE CONTENT ONLY FOR WINNERS =====
    // Gather unique IDs we actually need (top_display + candidates) and pull
    // article_content in bounded IN() batches. This avoids loading content for
    // every row during the similarity scan.
    $needed_ids = [];
    foreach ($top_display as $item) {
        $needed_ids[$item['id']] = true;
    }
    foreach ($candidates as $item) {
        $needed_ids[$item['id']] = true;
    }
    $needed_ids = array_keys($needed_ids);

    $content_map = [];
    if (!empty($needed_ids)) {
        foreach (array_chunk($needed_ids, 250) as $chunk_ids) {
            $placeholders = implode(',', array_fill(0, count($chunk_ids), '%d'));
            $rows = $wpdb->get_results($wpdb->prepare(
                "SELECT id, article_content FROM {$system_prompt_table} WHERE id IN ($placeholders)",
                ...$chunk_ids
            ));
            foreach ($rows as $r) {
                $content_map[$r->id] = $r->article_content;
            }
            unset($rows);
        }
    }

    // Build the all_similarities display array from the top 10
    $all_similarities = [];
    foreach ($top_display as $item) {
        $article_content_for_parse = $content_map[$item['id']] ?? '';
        $parsed_for_display = MxChat_Chunker::parse_stored_chunk($article_content_for_parse);
        $is_chunk = $parsed_for_display['is_chunked'];
        $chunk_meta = $parsed_for_display['metadata'];

        if (!empty($item['source_url']) && $item['source_url'] !== '#') {
            $source_display = $item['source_url'];
        } else {
            $content_preview = strip_tags($article_content_for_parse);
            $content_preview = preg_replace('/\s+/', ' ', $content_preview);
            $source_display = substr(trim($content_preview), 0, 50) . '...';
        }

        $all_similarities[] = [
            'document_id' => $item['id'],
            'similarity' => $item['similarity'],
            'similarity_percentage' => round($item['similarity'] * 100, 2),
            'above_threshold' => $item['similarity'] >= $similarity_threshold,
            'source_display' => $source_display,
            'content_preview' => substr(strip_tags($parsed_for_display['text'] ?? ''), 0, 100) . '...',
            'used_for_context' => false,
            'role_restriction' => $item['role_restriction'],
            'has_access' => $item['has_access'],
            'filtered_out' => !$item['has_access'],
            'is_chunk' => $is_chunk,
            'chunk_index' => $is_chunk ? ($chunk_meta['chunk_index'] ?? 0) : null,
            'total_chunks' => $is_chunk ? ($chunk_meta['total_chunks'] ?? 1) : null
        ];
    }

    // Build url_groups from candidates for chunk reassembly
    $url_groups = array();
    foreach ($candidates as $cand) {
        $article_content = $content_map[$cand['id']] ?? '';
        $parsed = MxChat_Chunker::parse_stored_chunk($article_content);
        $is_chunked = $parsed['is_chunked'];
        $chunk_index = $parsed['metadata']['chunk_index'] ?? 0;
        $text_content = $parsed['text'];

        $source_url = $cand['source_url'];
        $group_key = !empty($source_url) ? $source_url : '_manual_' . $cand['id'];

        if (!isset($url_groups[$group_key])) {
            $url_groups[$group_key] = array(
                'source_url' => $source_url,
                'best_score' => 0,
                'is_chunked' => $is_chunked,
                'chunks' => array(),
                'single_text' => '',
                'single_id' => null
            );
        }

        if ($cand['similarity'] > $url_groups[$group_key]['best_score']) {
            $url_groups[$group_key]['best_score'] = $cand['similarity'];
        }

        if ($is_chunked) {
            $url_groups[$group_key]['is_chunked'] = true;
            $url_groups[$group_key]['chunks'][] = array(
                'id' => $cand['id'],
                'score' => $cand['similarity'],
                'chunk_index' => $chunk_index,
                'text' => $text_content
            );
        } else {
            $url_groups[$group_key]['single_text'] = $text_content;
            $url_groups[$group_key]['single_id'] = $cand['id'];
        }
    }

    // Sort ALL similarities for testing display (highest first)
    usort($all_similarities, function ($a, $b) {
        return $b['similarity'] <=> $a['similarity'];
    });

    // Sort URL groups by best score (highest first)
    uasort($url_groups, function($a, $b) {
        return $b['best_score'] <=> $a['best_score'];
    });

    // Get RAG sources limit from options (default 6, min 3, max 10)
    $rag_sources_limit = isset($current_options['rag_sources_limit']) ? intval($current_options['rag_sources_limit']) : 3;
    if ($rag_sources_limit < 3) $rag_sources_limit = 3;
    if ($rag_sources_limit > 10) $rag_sources_limit = 10;

    // Take top N unique URLs based on user setting
    $top_urls = array_slice($url_groups, 0, $rag_sources_limit, true);

    // Track which document IDs are used for context
    $used_document_ids = [];
    foreach ($top_urls as $group) {
        if ($group['is_chunked']) {
            foreach ($group['chunks'] as $chunk) {
                $used_document_ids[] = $chunk['id'];
            }
        } elseif ($group['single_id']) {
            $used_document_ids[] = $group['single_id'];
        }
    }

    // Update the all_similarities array to mark which were actually used
    foreach ($all_similarities as &$similarity_item) {
        $similarity_item['used_for_context'] = in_array($similarity_item['document_id'], $used_document_ids);
    }

    // Store top 10 for testing panel
    $this->last_similarity_analysis['top_matches'] = array_slice($all_similarities, 0, 10);
    $this->last_similarity_analysis['total_checked'] = $total_checked;

    // Initialize final content
    $content = '';
    $matches_used = 0;
    $total_chunks_used = 0;
    $max_total_chunks = isset($current_options['rag_chunks_limit']) ? intval($current_options['rag_chunks_limit']) : 15;
    if ($max_total_chunks < 8) $max_total_chunks = 8;
    if ($max_total_chunks > 20) $max_total_chunks = 20;
    $max_chunks_per_source = 5; // Cap per individual source to limit token usage

    // Check if citation links are enabled (default to 'on' for backwards compatibility)
    // Use fresh options to ensure we get the latest setting value
    $fresh_options = get_option('mxchat_options', []);
    $citation_links_enabled = isset($fresh_options['citation_links_toggle']) ? ($fresh_options['citation_links_toggle'] === 'on') : true;

    // Build content from top sources
    foreach ($top_urls as $group_key => $group) {
        $source_url = $group['source_url']; // Use actual source_url, not the group key

        // Stop if we've hit the total chunk limit
        if ($total_chunks_used >= $max_total_chunks) {
            break;
        }

        $full_text = '';
        $chunks_in_this_source = 1; // Default for non-chunked content

        if ($group['is_chunked']) {
            // Calculate how many chunks we can still use (respect both total and per-source caps)
            $chunks_remaining = min($max_chunks_per_source, $max_total_chunks - $total_chunks_used);

            // Fetch chunks for this URL with limit
            $full_text = $this->reassemble_chunks_from_wordpress($source_url, $chunks_remaining, $chunks_in_this_source);

            // If fetching all chunks fails, fall back to matched chunks
            if (empty($full_text)) {
                // Sort matched chunks by index and concatenate
                usort($group['chunks'], function($a, $b) {
                    return $a['chunk_index'] <=> $b['chunk_index'];
                });

                $chunk_texts = array();
                $chunks_in_this_source = 0;
                foreach ($group['chunks'] as $chunk) {
                    if ($total_chunks_used + $chunks_in_this_source >= $max_total_chunks) {
                        break;
                    }
                    $chunk_texts[] = $chunk['text'];
                    $chunks_in_this_source++;
                }
                $full_text = implode("\n\n", $chunk_texts);
            }
        } else {
            $full_text = $group['single_text'];
            $chunks_in_this_source = 1;
        }

        if (!empty($full_text)) {
            // Strip URLs from content if citation links are disabled
            if (!$citation_links_enabled) {
                $full_text = preg_replace('#\bhttps?://[^\s<>"\']+#i', '', $full_text);
                $full_text = preg_replace('/\s+/', ' ', trim($full_text)); // Clean up extra spaces
            }

            // Use numbered reference for URL-based entries, plain info label for manual entries
            // Manual entries are stored with an internal mxchat:// placeholder URL — never expose them as citations
            if (!empty($source_url) && $source_url !== '#' && strpos($source_url, 'mxchat://') !== 0) {
                $matches_used++;
                $content .= "## Reference " . $matches_used . " ##\n";
                $content .= $full_text . "\n\n";

                // Only include citation URLs if citation links are enabled
                if ($citation_links_enabled) {
                    $valid_urls[] = $source_url;
                    $content .= "URL: " . $source_url . "\n\n";
                }

                // Video-backed source → queue the consent-safe embed (03ba33)
                $this->maybe_queue_youtube_embed($source_url, $full_text);
            } else {
                // Manual entry — no reference number, no citation
                $content .= "## Information ##\n";
                $content .= $full_text . "\n\n";
            }

            // Extract any URLs from the text content itself (only if citation links enabled)
            if ($citation_links_enabled) {
                preg_match_all(
                    '#\bhttps?://[^\s<>"\']+#i',
                    $full_text,
                    $content_urls
                );
                if (!empty($content_urls[0])) {
                    $valid_urls = array_merge($valid_urls, $content_urls[0]);
                }
            }

            $total_chunks_used += $chunks_in_this_source;
        }
    }

    // NEW: Store unique valid URLs for validation
    $this->current_valid_urls = array_unique($valid_urls);

    // Store sources and chunks counts for testing/transcript display
    $this->last_similarity_analysis['sources_used'] = $matches_used;
    $this->last_similarity_analysis['total_chunks_used'] = $total_chunks_used;

    // Allow add-ons to act on similarity results (e.g. WooCommerce product card display)
    do_action('mxchat_similarity_results', $this->last_similarity_analysis['top_matches'], $bot_id);

    // Add response guidelines
    if (empty($top_urls)) {
        $content = "No reference information was found for this query.\n\n";
    } else {
        // Build response guidelines based on citation links setting
        $content .= "\n## Response Guidelines ##\n" .
                   "You are an AI Chatbot. Answer naturally and helpfully using only the information from the references above. " .
                   "Be conversational and friendly, but never mention your knowledge base or training data. " .
                   "If you don't have specific information or are uncertain about any details, it's always " .
                   "better to honestly say you don't know rather than making up or guessing at answers. " .
                   "When information is incomplete, let them know you are unsure.\n\n";

        // Only add hyperlink instructions if citation links are enabled
        if ($citation_links_enabled) {
            $content .= "CRITICAL: When creating hyperlinks, always use proper markdown format with descriptive text: " .
                       "[descriptive text](url). NEVER use empty brackets like [](url). The text in brackets must describe what the link is about. " .
                       "Only cite references that have a URL. Do not cite or add source labels to Information sections that have no URL.";
        } else {
            $content .= "IMPORTANT: Do not include any citation links, source URLs, or hyperlinks in your responses. " .
                       "Simply provide helpful answers based on the reference information without citing sources.";
        }
    }

    return trim($content);
}

/**
 * plan-mxchat-20260717-03ba33 — if a KB source used for context is a single
 * YouTube video, queue ONE consent-safe embed for the response html channel.
 * Called from BOTH retrieval builders (WordPress DB + Pinecone) inside their
 * real-URL winner branch, in ranked order — so the first (best) video wins and
 * later matches are ignored. Only KB/admin-ingested sources ever reach this
 * point; a URL a visitor pastes in chat never does.
 */
private function maybe_queue_youtube_embed($source_url, $full_text) {
    if (!empty($this->videoEmbedHtml)) {
        return; // one video per response
    }
    $video_id = MxChat_Utils::parse_youtube_id($source_url);
    if (empty($video_id)) {
        return;
    }
    // Ingestion writes "YouTube Video: {title}" / "Channel: {name}" / "URL: …"
    // header lines into the indexed text. NOTE: when citation links are
    // disabled the winner loop collapses ALL whitespace to single spaces
    // before this runs, so the title must be terminated by the next header
    // label, not by end-of-line. Fall back to a generic label when absent
    // (e.g. a YouTube watch page imported through the plain URL source).
    $title = '';
    if (preg_match('/YouTube Video:\s*(.+?)(?=\s+Channel:\s|\s+URL:\s|\r|\n|$)/i', (string) $full_text, $m)) {
        $title = trim(mb_substr(trim($m[1]), 0, 140));
        if (preg_match('#^https?://#i', $title)) {
            $title = ''; // header carried the URL, not a real title
        }
    }
    $this->videoEmbedHtml = $this->build_youtube_embed_html($video_id, $title, $source_url);
}

/**
 * Consent-safe click-to-load YouTube facade. No Google iframe is created until
 * the visitor taps play (chat-script.js swaps the facade for a
 * youtube-nocookie.com iframe). The caption always carries a plain "Watch on
 * YouTube" link, which is also the graceful degrade on strict-CSP sites where
 * third-party frames are blocked.
 */
private function build_youtube_embed_html($video_id, $title, $watch_url) {
    $video_id = preg_replace('/[^A-Za-z0-9_-]/', '', (string) $video_id);
    if ($video_id === '') {
        return '';
    }
    $thumb = 'https://i.ytimg.com/vi/' . $video_id . '/hqdefault.jpg';
    $label = ($title !== '') ? $title : __('YouTube video', 'mxchat');

    $html  = '
';
    $html .= '';
    $html .= '';
    $html .= '';
    $html .= '';
    $html .= '
';
    $html .= '' . esc_html($label) . '';
    $html .= '' . esc_html__('Watch on YouTube', 'mxchat') . '';
    $html .= '
';
    $html .= '
';
    return $html;
}

/**
 * Fetch and reassemble chunks for a URL from WordPress database
 *
 * @param string $source_url The source URL to fetch chunks for
 * @param int $max_chunks Maximum number of chunks to return (0 = unlimited)
 * @param int &$chunk_count Reference to store the actual number of chunks returned
 * @return string Reassembled content from chunks
 */
private function reassemble_chunks_from_wordpress($source_url, $max_chunks = 0, &$chunk_count = 0) {
    global $wpdb;
    $table = $wpdb->prefix . 'mxchat_system_prompt_content';

    // Fetch all rows with this source_url
    $rows = $wpdb->get_results($wpdb->prepare(
        "SELECT article_content FROM {$table}
         WHERE source_url = %s
         ORDER BY id ASC",
        $source_url
    ));

    if (empty($rows)) {
        $chunk_count = 0;
        return '';
    }

    // Parse and sort chunks by index
    $chunks = array();
    foreach ($rows as $row) {
        $parsed = MxChat_Chunker::parse_stored_chunk($row->article_content);

        if ($parsed['is_chunked']) {
            $chunk_index = $parsed['metadata']['chunk_index'] ?? 0;
            $chunks[$chunk_index] = $parsed['text'];
        } else {
            // Non-chunked content - just return it
            $chunks[] = $parsed['text'];
        }
    }

    // Sort by chunk index
    ksort($chunks);

    // Apply chunk limit if specified
    if ($max_chunks > 0 && count($chunks) > $max_chunks) {
        $chunks = array_slice($chunks, 0, $max_chunks, true);
    }

    // Store actual chunk count
    $chunk_count = count($chunks);

    // Reassemble content
    return implode("\n\n", $chunks);
}

private function find_relevant_content_pinecone($user_embedding, $bot_id = 'default', $bot_config = null) {
    global $wpdb;
    
    //error_log("MXCHAT DEBUG: find_relevant_content_pinecone called");
    //error_log("  - bot_id: " . $bot_id);
    //error_log("  - user_embedding is array: " . (is_array($user_embedding) ? 'yes' : 'no'));
    //error_log("  - user_embedding count: " . (is_array($user_embedding) ? count($user_embedding) : 'N/A'));
    
    // Use bot-specific config or fall back to default
    if ($bot_config === null) {
        $bot_config = $this->get_bot_pinecone_config($bot_id);
    }
    
    $api_key = $bot_config['api_key'] ?? '';
    $host = $bot_config['host'] ?? '';
    $namespace = $bot_config['namespace'] ?? '';
    
    //error_log("MXCHAT DEBUG: Pinecone query parameters:");
    //error_log("  - API Key: " . (empty($api_key) ? 'EMPTY - ERROR!' : 'Present (length: ' . strlen($api_key) . ')'));
    //error_log("  - Host: " . (empty($host) ? 'EMPTY - ERROR!' : $host));
    //error_log("  - Namespace: " . (empty($namespace) ? 'EMPTY (will use default)' : $namespace));
    
    // Initialize similarity analysis storage
    $this->last_similarity_analysis = [
        'knowledge_base_type' => 'Pinecone',
        'bot_id' => $bot_id,
        'namespace' => $namespace,
        'top_matches' => [],
        'threshold_used' => 0,
        'total_checked' => 0
    ];
    
    // NEW: Initialize valid URLs array
    $valid_urls = [];
    
    if (empty($host) || empty($api_key)) {
        //error_log("MXCHAT DEBUG ERROR: Missing Pinecone host or API key!");
        //error_log("  - Host empty: " . (empty($host) ? 'YES' : 'NO'));
        //error_log("  - API key empty: " . (empty($api_key) ? 'YES' : 'NO'));
        // Store empty array for valid URLs since we can't proceed
        $this->current_valid_urls = [];
        return '';
    }
    
    // Get knowledge manager instance for role checking
    $knowledge_manager = MxChat_Knowledge_Manager::get_instance();
    
    // Get the similarity threshold from the bot options or main options
    $bot_options = $this->get_bot_options($bot_id);
    $current_options = !empty($bot_options) ? $bot_options : get_option('mxchat_options', []);
    
    $similarity_threshold = isset($current_options['similarity_threshold']) 
        ? ((int) $current_options['similarity_threshold']) / 100 
        : 0.35;
    
    $this->last_similarity_analysis['threshold_used'] = $similarity_threshold;
    
    // Prepare the query request for Pinecone
    $api_endpoint = "https://{$host}/query";
    
    $request_body = array(
        'vector' => $user_embedding,
        'topK' => 50, // Increased for chunked content grouping - need more candidates to find top N unique URLs
        'includeMetadata' => true,
        'includeValues' => true
    );
    
    // Add namespace if specified for this bot
    if (!empty($namespace)) {
        $request_body['namespace'] = $namespace;
    }
    
    //error_log("MXCHAT DEBUG: About to call Pinecone API");
    //error_log("  - Endpoint: " . $api_endpoint);
    //error_log("  - Namespace in request: " . (!empty($namespace) ? $namespace : 'NOT SET'));
    
    $response = wp_remote_post($api_endpoint, array(
        'headers' => array(
            'Api-Key' => $api_key,
            'accept' => 'application/json',
            'content-type' => 'application/json'
        ),
        'body' => wp_json_encode($request_body),
        'timeout' => 30
    ));
    
    if (is_wp_error($response)) {
        //error_log("MXCHAT DEBUG ERROR: WP Error in Pinecone request: " . $response->get_error_message());
        // Store empty array for valid URLs
        $this->current_valid_urls = [];
        return '';
    }
    
    $response_code = wp_remote_retrieve_response_code($response);
    //error_log("MXCHAT DEBUG: Pinecone response code: " . $response_code);
    
    if ($response_code !== 200) {
        $response_body = wp_remote_retrieve_body($response);
        //error_log("MXCHAT DEBUG ERROR: Pinecone API error response: " . substr($response_body, 0, 500));
        // Store empty array for valid URLs
        $this->current_valid_urls = [];
        return '';
    }
    
    // ADD DETAILED DEBUG SECTION HERE
    $response_body = wp_remote_retrieve_body($response);
    //error_log("MXCHAT DEBUG: Raw Pinecone response length: " . strlen($response_body));
    
    $results = json_decode($response_body, true);
    
    if (json_last_error() !== JSON_ERROR_NONE) {
        //error_log("MXCHAT DEBUG ERROR: JSON decode error: " . json_last_error_msg());
        //error_log("MXCHAT DEBUG: First 500 chars of response: " . substr($response_body, 0, 500));
        // Store empty array for valid URLs
        $this->current_valid_urls = [];
        return '';
    }
    
    //error_log("MXCHAT DEBUG: Pinecone response structure:");
    //error_log("  - Has 'matches' key: " . (isset($results['matches']) ? 'yes' : 'no'));
    //error_log("  - Has 'namespace' key: " . (isset($results['namespace']) ? 'yes (' . $results['namespace'] . ')' : 'no'));
    
    if (empty($results['matches'])) {
        //error_log("MXCHAT DEBUG: No matches found in Pinecone response");
        //error_log("MXCHAT DEBUG: Response keys: " . implode(', ', array_keys($results)));
        // Store empty array for valid URLs
        $this->current_valid_urls = [];
        return '';
    }
    
    //error_log("MXCHAT DEBUG: Found " . count($results['matches']) . " matches in Pinecone");
    
    // Log first match details for debugging
    if (!empty($results['matches'][0])) {
        $first_match = $results['matches'][0];
        //error_log("MXCHAT DEBUG: First match details:");
        //error_log("  - Score: " . ($first_match['score'] ?? 'no score'));
        //error_log("  - Has metadata: " . (isset($first_match['metadata']) ? 'yes' : 'no'));
        if (isset($first_match['metadata'])) {
            //error_log("  - Metadata keys: " . implode(', ', array_keys($first_match['metadata'])));
        }
    }
    
    // Initialize the final content
    $content = '';
    $matches_used = 0;
    $matches_used_for_context = [];
    $total_chunks_used = 0;
    $max_total_chunks = isset($current_options['rag_chunks_limit']) ? intval($current_options['rag_chunks_limit']) : 15;
    if ($max_total_chunks < 8) $max_total_chunks = 8;
    if ($max_total_chunks > 20) $max_total_chunks = 20;
    $max_chunks_per_source = 5; // Cap per individual source to limit token usage

    // Check if citation links are enabled (default to 'on' for backwards compatibility)
    // Use fresh options to ensure we get the latest setting value
    $fresh_options = get_option('mxchat_options', []);
    $citation_links_enabled = isset($fresh_options['citation_links_toggle']) ? ($fresh_options['citation_links_toggle'] === 'on') : true;

    // NEW CHUNKING LOGIC: Group results by source_url for chunk reassembly
    $url_groups = array();

    foreach ($results['matches'] as $index => $match) {
        // Skip if similarity is below threshold
        if ($match['score'] < $similarity_threshold) {
            continue;
        }

        $metadata = $match['metadata'] ?? array();
        $source_url = $metadata['source_url'] ?? '';
        $match_id = $match['id'] ?? '';

        // LAZY ROLE CHECK: Only check role for content we're actually considering
        $role_restriction = $this->get_single_vector_role($match_id, $metadata);
        $has_access = $knowledge_manager->mxchat_user_has_content_access($role_restriction);

        // Skip if user doesn't have access
        if (!$has_access) {
            continue;
        }

        // Use a unique key for manual entries without a source URL
        $group_key = !empty($source_url) ? $source_url : '_manual_' . $match_id;

        // Group by source URL (or unique key for manual entries)
        if (!isset($url_groups[$group_key])) {
            $url_groups[$group_key] = array(
                'source_url' => $source_url,
                'best_score' => 0,
                'is_chunked' => isset($metadata['is_chunked']) && $metadata['is_chunked'],
                'chunks' => array(),
                'single_text' => ''
            );
        }

        // Track best score for this group
        if ($match['score'] > $url_groups[$group_key]['best_score']) {
            $url_groups[$group_key]['best_score'] = $match['score'];
        }

        // Store chunk info or single text
        if ($url_groups[$group_key]['is_chunked']) {
            $url_groups[$group_key]['chunks'][] = array(
                'id' => $match_id,
                'score' => $match['score'],
                'chunk_index' => $metadata['chunk_index'] ?? 0,
                'text' => $metadata['text'] ?? ''
            );
        } else {
            // Non-chunked content - just store the text
            $url_groups[$group_key]['single_text'] = $metadata['text'] ?? '';
            $url_groups[$group_key]['single_id'] = $match_id;
        }
    }

    // Sort URL groups by best score (highest first)
    uasort($url_groups, function($a, $b) {
        return $b['best_score'] <=> $a['best_score'];
    });

    // Get RAG sources limit from options (default 6, min 3, max 10)
    $rag_sources_limit = isset($current_options['rag_sources_limit']) ? intval($current_options['rag_sources_limit']) : 3;
    if ($rag_sources_limit < 3) $rag_sources_limit = 3;
    if ($rag_sources_limit > 10) $rag_sources_limit = 10;

    // Take top N unique URLs based on user setting
    $top_urls = array_slice($url_groups, 0, $rag_sources_limit, true);

    // Track which match IDs are actually used for context
    foreach ($top_urls as $group) {
        if ($group['is_chunked']) {
            foreach ($group['chunks'] as $chunk) {
                $matches_used_for_context[] = $chunk['id'];
            }
        } elseif (!empty($group['single_id'])) {
            $matches_used_for_context[] = $group['single_id'];
        }
    }

    // Build content from top sources
    foreach ($top_urls as $group_key => $group) {
        $source_url = $group['source_url']; // Use actual source_url, not the group key

        // Stop if we've hit the total chunk limit
        if ($total_chunks_used >= $max_total_chunks) {
            break;
        }

        $full_text = '';
        $chunks_in_this_source = 1; // Default for non-chunked content

        if ($group['is_chunked']) {
            // Calculate how many chunks we can still use (respect both total and per-source caps)
            $chunks_remaining = min($max_chunks_per_source, $max_total_chunks - $total_chunks_used);

            // Fetch chunks for this URL with limit
            $full_text = $this->reassemble_chunks_from_pinecone($source_url, $bot_config, $chunks_remaining, $chunks_in_this_source);

            // If fetching all chunks fails, fall back to matched chunks
            if (empty($full_text)) {
                // Sort matched chunks by index and concatenate
                usort($group['chunks'], function($a, $b) {
                    return $a['chunk_index'] <=> $b['chunk_index'];
                });

                $chunk_texts = array();
                $chunks_in_this_source = 0;
                foreach ($group['chunks'] as $chunk) {
                    if ($total_chunks_used + $chunks_in_this_source >= $max_total_chunks) {
                        break;
                    }
                    $chunk_texts[] = $chunk['text'];
                    $chunks_in_this_source++;
                }
                $full_text = implode("\n\n", $chunk_texts);
            }
        } else {
            $full_text = $group['single_text'];
            $chunks_in_this_source = 1;
        }

        if (!empty($full_text)) {
            // Strip URLs from content if citation links are disabled
            if (!$citation_links_enabled) {
                $full_text = preg_replace('#\bhttps?://[^\s<>"\']+#i', '', $full_text);
                $full_text = preg_replace('/\s+/', ' ', trim($full_text)); // Clean up extra spaces
            }

            // Use numbered reference for URL-based entries, plain info label for manual entries
            // Manual entries are stored with an internal mxchat:// placeholder URL — never expose them as citations
            if (!empty($source_url) && $source_url !== '#' && strpos($source_url, 'mxchat://') !== 0) {
                $matches_used++;
                $content .= "## Reference " . $matches_used . " ##\n";
                $content .= $full_text . "\n\n";

                // Only include citation URLs if citation links are enabled
                if ($citation_links_enabled) {
                    $valid_urls[] = $source_url;
                    $content .= "URL: " . $source_url . "\n\n";
                }

                // Video-backed source → queue the consent-safe embed (03ba33)
                $this->maybe_queue_youtube_embed($source_url, $full_text);
            } else {
                // Manual entry — no reference number, no citation. Count it as a USED
                // source (plan-mxchat-20260622-c1fe6a): without this, manual/Direct-Content
                // entries (empty or mxchat:// source_url) never increment $matches_used, so
                // the gate below (`if ($matches_used === 0)`) discards manual-only context on
                // the Pinecone backend and the model is told "No reference information was
                // found" — even though the testing panel reports used_for_context:true. It
                // also corrects the cosmetic sources_used:0 the panel/transcript showed. The
                // sibling local/WP-DB builder gates on empty($top_urls), so it never had this
                // bug; this brings Pinecone to parity. Manual entries are still uncited (not
                // added to $valid_urls, no "URL:" line).
                $matches_used++;
                $content .= "## Information ##\n";
                $content .= $full_text . "\n\n";
            }

            // Extract any URLs from the text content itself (only if citation links enabled)
            if ($citation_links_enabled) {
                preg_match_all(
                    '#\bhttps?://[^\s<>"\']+#i',
                    $full_text,
                    $content_urls
                );
                if (!empty($content_urls[0])) {
                    $valid_urls = array_merge($valid_urls, $content_urls[0]);
                }
            }

            $total_chunks_used += $chunks_in_this_source;
        }
    }

    // Process ALL matches for testing data (top 10) - with role checking for testing display
    $all_matches = [];
    foreach ($results['matches'] as $index => $match) {
        if ($index >= 10) break; // Limit to top 10 for testing
        
        $match_id = $match['id'] ?? '';
        
        // Check role access for testing display (use cache if available)
        $role_restriction = $this->get_single_vector_role($match_id, $match['metadata']);
        $has_access = $knowledge_manager->mxchat_user_has_content_access($role_restriction);
        
        $source_display = '';
        if (!empty($match['metadata']['source_url'])) {
            $source_display = $match['metadata']['source_url'];
        } else {
            $content_preview = strip_tags($match['metadata']['text'] ?? '');
            $content_preview = preg_replace('/\s+/', ' ', $content_preview);
            $source_display = substr(trim($content_preview), 0, 50) . '...';
        }
        
        $match_id_for_display = $match['id'] ?? $index;

        // Check for chunk metadata in Pinecone
        $is_chunk = isset($match['metadata']['is_chunked']) && $match['metadata']['is_chunked'];
        $chunk_index = isset($match['metadata']['chunk_index']) ? intval($match['metadata']['chunk_index']) : null;
        $total_chunks = isset($match['metadata']['total_chunks']) ? intval($match['metadata']['total_chunks']) : null;

        // Also detect chunk from vector ID pattern: {hash}_chunk_{index}
        if (!$is_chunk && MxChat_Chunker::is_chunk_vector_id($match_id_for_display)) {
            $is_chunk = true;
        }

        $all_matches[] = [
            'document_id' => $match_id_for_display,
            'similarity' => $match['score'],
            'similarity_percentage' => round($match['score'] * 100, 2),
            'above_threshold' => $match['score'] >= $similarity_threshold,
            'source_display' => $source_display,
            'content_preview' => substr(strip_tags($match['metadata']['text'] ?? ''), 0, 100) . '...',
            'used_for_context' => in_array($match_id_for_display, $matches_used_for_context),
            'role_restriction' => $role_restriction,
            'has_access' => $has_access,
            'filtered_out' => !$has_access,
            'is_chunk' => $is_chunk,
            'chunk_index' => $chunk_index,
            'total_chunks' => $total_chunks
        ];
    }
    
    // Store for testing panel
    $this->last_similarity_analysis['top_matches'] = $all_matches;
    $this->last_similarity_analysis['total_checked'] = count($results['matches']);
    $this->last_similarity_analysis['sources_used'] = $matches_used;
    $this->last_similarity_analysis['total_chunks_used'] = $total_chunks_used;

    // NEW: Store unique valid URLs for validation
    $this->current_valid_urls = array_unique($valid_urls);

    // Allow add-ons to act on similarity results (e.g. WooCommerce product card display)
    do_action('mxchat_similarity_results', $this->last_similarity_analysis['top_matches'], $bot_id);

    // Add response guidelines
    if ($matches_used === 0) {
        $content = "No reference information was found for this query.\n\n";
    } else {
        // Build response guidelines based on citation links setting
        $content .= "\n## Response Guidelines ##\n" .
                   "You are an AI Chatbot. Answer naturally and helpfully using only the information from the references above. " .
                   "Be conversational and friendly, but never mention your knowledge base or training data. " .
                   "If you don't have specific information or are uncertain about any details, it's always " .
                   "better to honestly say you don't know rather than making up or guessing at answers. " .
                   "When information is incomplete, let them know you are unsure.\n\n";

        // Only add hyperlink instructions if citation links are enabled
        if ($citation_links_enabled) {
            $content .= "CRITICAL: When creating hyperlinks, always use proper markdown format with descriptive text: " .
                       "[descriptive text](url). NEVER use empty brackets like [](url). The text in brackets must describe what the link is about. " .
                       "Only cite references that have a URL. Do not cite or add source labels to Information sections that have no URL.";
        } else {
            $content .= "IMPORTANT: Do not include any citation links, source URLs, or hyperlinks in your responses. " .
                       "Simply provide helpful answers based on the reference information without citing sources.";
        }
    }

    return trim($content);
}

/**
 * Get role restriction for a single vector (with caching)
 */
private function get_single_vector_role($vector_id, $metadata = array()) {
    global $wpdb;
    
    if (empty($vector_id)) {
        return 'public';
    }
    
    // Check cache first
    $cache_key = 'mxchat_vector_role_' . $vector_id;
    $cached_role = wp_cache_get($cache_key, 'mxchat_vector_roles');
    
    if ($cached_role !== false) {
        return $cached_role;
    }
    
    $role_restriction = 'public';
    
    // First try Pinecone metadata
    if (!empty($metadata['role_restriction'])) {
        $role_restriction = $metadata['role_restriction'];
    } else {
        // Check WordPress table for user-modified roles
        $roles_table = $wpdb->prefix . 'mxchat_pinecone_roles';
        $stored_role = $wpdb->get_var($wpdb->prepare(
            "SELECT role_restriction FROM {$roles_table} WHERE vector_id = %s",
            $vector_id
        ));
        
        if ($stored_role) {
            $role_restriction = $stored_role;
        }
    }
    
    // Cache individual role for 1 hour
    wp_cache_set($cache_key, $role_restriction, 'mxchat_vector_roles', 3600);

    return $role_restriction;
}

/**
 * Fetch and reassemble all chunks for a URL from Pinecone
 *
 * @param string $source_url The source URL to fetch chunks for
 * @param array $bot_config Bot-specific Pinecone configuration
 * @return string Reassembled content from all chunks
 */
private function reassemble_chunks_from_pinecone($source_url, $bot_config, $max_chunks = 0, &$chunk_count = 0) {
    $api_key = $bot_config['api_key'] ?? '';
    $host = $bot_config['host'] ?? '';
    $namespace = $bot_config['namespace'] ?? '';

    if (empty($host) || empty($api_key)) {
        $chunk_count = 0;
        return '';
    }

    $base_hash = md5($source_url);

    // Use Pinecone list API to find all chunk vectors with this prefix
    $list_url = "https://{$host}/vectors/list";

    // Limit to max_chunks if specified, otherwise fetch up to 100
    $fetch_limit = ($max_chunks > 0 && $max_chunks < 100) ? $max_chunks : 100;

    $list_body = array(
        'prefix' => $base_hash . '_chunk_',
        'limit' => $fetch_limit
    );

    if (!empty($namespace)) {
        $list_body['namespace'] = $namespace;
    }

    $list_response = wp_remote_post($list_url, array(
        'headers' => array(
            'Api-Key' => $api_key,
            'accept' => 'application/json',
            'content-type' => 'application/json'
        ),
        'body' => wp_json_encode($list_body),
        'timeout' => 30
    ));

    if (is_wp_error($list_response)) {
        //error_log('[MXCHAT-CHUNK] List API error: ' . $list_response->get_error_message());
        return '';
    }

    $list_data = json_decode(wp_remote_retrieve_body($list_response), true);

    if (empty($list_data['vectors'])) {
        //error_log('[MXCHAT-CHUNK] No chunk vectors found for URL: ' . $source_url);
        return '';
    }

    // Extract vector IDs
    $vector_ids = array();
    foreach ($list_data['vectors'] as $vector) {
        if (isset($vector['id'])) {
            $vector_ids[] = $vector['id'];
        }
    }

    if (empty($vector_ids)) {
        return '';
    }

    // Fetch all chunk content
    $fetch_url = "https://{$host}/vectors/fetch";

    $fetch_body = array(
        'ids' => $vector_ids
    );

    if (!empty($namespace)) {
        $fetch_body['namespace'] = $namespace;
    }

    $fetch_response = wp_remote_post($fetch_url, array(
        'headers' => array(
            'Api-Key' => $api_key,
            'accept' => 'application/json',
            'content-type' => 'application/json'
        ),
        'body' => wp_json_encode($fetch_body),
        'timeout' => 30
    ));

    if (is_wp_error($fetch_response)) {
        //error_log('[MXCHAT-CHUNK] Fetch API error: ' . $fetch_response->get_error_message());
        return '';
    }

    $fetch_data = json_decode(wp_remote_retrieve_body($fetch_response), true);

    if (empty($fetch_data['vectors'])) {
        return '';
    }

    // Sort chunks by index and reassemble
    $chunks = array();
    foreach ($fetch_data['vectors'] as $id => $vector) {
        $metadata = $vector['metadata'] ?? array();
        $chunk_index = $metadata['chunk_index'] ?? 0;
        $text = $metadata['text'] ?? '';

        // Store chunk with its index
        $chunks[$chunk_index] = $text;
    }

    // Sort by chunk index
    ksort($chunks);

    // Apply chunk limit if specified
    if ($max_chunks > 0 && count($chunks) > $max_chunks) {
        $chunks = array_slice($chunks, 0, $max_chunks, true);
    }

    // Store actual chunk count
    $chunk_count = count($chunks);

    // Reassemble content
    return implode("\n\n", $chunks);
}

/**
 * Search for relevant content using OpenAI Vector Store (File Search)
 *
 * @param string $user_query The user's query text
 * @param string $bot_id The bot ID
 * @param array $vectorstore_config Vector Store configuration
 * @return string Formatted context string with references
 */
private function find_relevant_content_openai_vectorstore($user_query, $bot_id = 'default', $vectorstore_config = array()) {
    //error_log("MXCHAT DEBUG: find_relevant_content_openai_vectorstore called");
    //error_log("  - bot_id: " . $bot_id);
    //error_log("  - user_query length: " . strlen($user_query));

    // Get OpenAI API key
    $mxchat_options = get_option('mxchat_options', array());
    $api_key = $mxchat_options['api_key'] ?? '';

    // Reset vectorstore error tracking
    $this->last_vectorstore_error = null;

    if (empty($api_key)) {
        //error_log("MXCHAT DEBUG ERROR: OpenAI API key not configured");
        $this->last_vectorstore_error = 'Vector Store search failed: OpenAI API key is not configured.';
        $this->current_valid_urls = [];
        return '';
    }

    // Get Vector Store configuration
    if (empty($vectorstore_config)) {
        $vectorstore_config = $this->get_bot_vectorstore_config($bot_id);
    }

    $vectorstore_ids_string = $vectorstore_config['vectorstore_ids'] ?? '';
    $max_results = $vectorstore_config['max_results'] ?? 5;

    if (empty($vectorstore_ids_string)) {
        //error_log("MXCHAT DEBUG ERROR: No Vector Store IDs configured");
        $this->last_vectorstore_error = 'Vector Store search failed: No Vector Store IDs are configured for this bot.';
        $this->current_valid_urls = [];
        return '';
    }

    // Parse Vector Store IDs
    $vectorstore_ids = array_map('trim', explode(',', $vectorstore_ids_string));
    $vectorstore_ids = array_filter($vectorstore_ids); // Remove empty values

    //error_log("MXCHAT DEBUG: Vector Store IDs: " . implode(', ', $vectorstore_ids));
    //error_log("MXCHAT DEBUG: Max results: " . $max_results);

    // Initialize similarity analysis storage
    $this->last_similarity_analysis = [
        'knowledge_base_type' => 'OpenAI Vector Store',
        'bot_id' => $bot_id,
        'vectorstore_ids' => $vectorstore_ids,
        'top_matches' => [],
        'threshold_used' => 0,
        'total_checked' => 0
    ];

    $valid_urls = [];

    // Get the selected model
    $bot_options = $this->get_bot_options($bot_id);
    $current_options = !empty($bot_options) ? $bot_options : $mxchat_options;
    $selected_model = $current_options['model'] ?? 'gpt-5.1-chat-latest';

    // Verify it's an OpenAI model
    if (!$this->is_openai_chat_model($selected_model)) {
        //error_log("MXCHAT DEBUG ERROR: Vector Store search requires OpenAI model. Current: " . $selected_model);
        $this->last_vectorstore_error = 'Vector Store search requires an OpenAI model. Current model: ' . $selected_model;
        $this->current_valid_urls = [];
        return '';
    }

    // Use OpenAI Responses API with file_search tool
    $request_body = array(
        'model' => $selected_model,
        'input' => $user_query,
        'tools' => array(
            array(
                'type' => 'file_search',
                'vector_store_ids' => $vectorstore_ids,
                'max_num_results' => intval($max_results)
            )
        ),
        'include' => array('output[*].file_search_call.search_results')
    );

    //error_log("MXCHAT VECTORSTORE: ========== REQUEST START ==========");
    //error_log("MXCHAT VECTORSTORE: Model: " . $selected_model);
    //error_log("MXCHAT VECTORSTORE: Query: " . substr($user_query, 0, 200));
    //error_log("MXCHAT VECTORSTORE: Vector Store IDs: " . implode(', ', $vectorstore_ids));
    //error_log("MXCHAT VECTORSTORE: Max Results: " . $max_results);
    //error_log("MXCHAT VECTORSTORE: Request body: " . wp_json_encode($request_body));

    $response = wp_remote_post('https://api.openai.com/v1/responses', array(
        'headers' => array(
            'Authorization' => 'Bearer ' . $api_key,
            'Content-Type' => 'application/json'
        ),
        'body' => wp_json_encode($request_body),
        'timeout' => 60
    ));

    if (is_wp_error($response)) {
        //error_log("MXCHAT VECTORSTORE ERROR: WP Error: " . $response->get_error_message());
        $this->last_vectorstore_error = 'Vector Store API request failed: ' . $response->get_error_message();
        $this->current_valid_urls = [];
        return '';
    }

    $response_code = wp_remote_retrieve_response_code($response);
    //error_log("MXCHAT VECTORSTORE: Response code: " . $response_code);

    $response_body = wp_remote_retrieve_body($response);
    //error_log("MXCHAT VECTORSTORE: Raw response (first 2000 chars): " . substr($response_body, 0, 2000));

    if ($response_code !== 200) {
        //error_log("MXCHAT VECTORSTORE ERROR: API error response: " . $response_body);
        $decoded_error = json_decode($response_body, true);
        $api_error_detail = $this->extract_provider_error($decoded_error, '');
        $this->last_vectorstore_error = 'Vector Store API returned HTTP ' . $response_code . ($api_error_detail ? ': ' . $api_error_detail : '');
        $this->current_valid_urls = [];
        return '';
    }
    $result = json_decode($response_body, true);

    if (json_last_error() !== JSON_ERROR_NONE) {
        //error_log("MXCHAT VECTORSTORE ERROR: JSON decode error: " . json_last_error_msg());
        $this->last_vectorstore_error = 'Vector Store response could not be parsed: ' . json_last_error_msg();
        $this->current_valid_urls = [];
        return '';
    }

    // Debug: Log the structure of the result
    //error_log("MXCHAT VECTORSTORE: Result keys: " . implode(', ', array_keys($result)));
    if (isset($result['output'])) {
        //error_log("MXCHAT VECTORSTORE: Output count: " . count($result['output']));
        foreach ($result['output'] as $idx => $out) {
            //error_log("MXCHAT VECTORSTORE: Output[$idx] type: " . ($out['type'] ?? 'unknown'));
            //error_log("MXCHAT VECTORSTORE: Output[$idx] keys: " . implode(', ', array_keys($out)));
        }
    } else {
        //error_log("MXCHAT VECTORSTORE: No 'output' key in result!");
    }

    // Extract file search results from the response
    $content = '';
    $matches_used = 0;
    $all_matches = [];

    // The Responses API returns output array with tool results
    if (isset($result['output']) && is_array($result['output'])) {
        foreach ($result['output'] as $output_item) {
            // Look for file_search_call results
            if (isset($output_item['type']) && $output_item['type'] === 'file_search_call') {
                //error_log("MXCHAT VECTORSTORE: Found file_search_call output item");
                //error_log("MXCHAT VECTORSTORE: file_search_call keys: " . implode(', ', array_keys($output_item)));

                // Check for search_results in the output item directly
                $search_results = $output_item['search_results'] ?? $output_item['results'] ?? [];
                //error_log("MXCHAT VECTORSTORE: Search results count: " . count($search_results));

                if (empty($search_results)) {
                    //error_log("MXCHAT VECTORSTORE: No search results found in file_search_call");
                    //error_log("MXCHAT VECTORSTORE: file_search_call content: " . wp_json_encode($output_item));
                }

                foreach ($search_results as $index => $search_result) {
                    $filename = $search_result['filename'] ?? '';
                    $score = $search_result['score'] ?? 0;
                    $text_content = '';

                    // Extract text content from the result
                    // The text can be directly on the result OR nested under content array
                    if (isset($search_result['text']) && !empty($search_result['text'])) {
                        // Direct text field (OpenAI's actual format)
                        $text_content = $search_result['text'];
                        //error_log("MXCHAT VECTORSTORE: Found text directly on result[$index], length: " . strlen($text_content));
                    } elseif (isset($search_result['content']) && is_array($search_result['content'])) {
                        // Nested content array format
                        foreach ($search_result['content'] as $content_item) {
                            if (isset($content_item['text'])) {
                                $text_content .= $content_item['text'] . "\n";
                            }
                        }
                        //error_log("MXCHAT VECTORSTORE: Found text in content array for result[$index], length: " . strlen($text_content));
                    } else {
                        //error_log("MXCHAT VECTORSTORE: No text found for result[$index]. Keys: " . implode(', ', array_keys($search_result)));
                    }

                    if (!empty($text_content)) {
                        $content .= "## Reference " . ($matches_used + 1) . " ##\n";
                        $content .= trim($text_content) . "\n\n";

                        if (!empty($filename)) {
                            $content .= "Source: " . $filename . "\n\n";
                        }

                        // Extract URLs from content
                        preg_match_all(
                            '#\bhttps?://[^\s<>"\']+#i',
                            $text_content,
                            $content_urls
                        );
                        if (!empty($content_urls[0])) {
                            $valid_urls = array_merge($valid_urls, $content_urls[0]);
                        }

                        $matches_used++;
                    }

                    // Store for similarity analysis
                    $all_matches[] = [
                        'document_id' => $filename ?: ('result_' . $index),
                        'similarity' => $score,
                        'similarity_percentage' => round($score * 100, 2),
                        'above_threshold' => true,
                        'source_display' => $filename,
                        'content_preview' => substr(strip_tags($text_content), 0, 100) . '...',
                        'used_for_context' => true,
                        'role_restriction' => 'public',
                        'has_access' => true,
                        'filtered_out' => false
                    ];
                }
            }

            // Also check for message content with annotations (citations)
            if (isset($output_item['type']) && $output_item['type'] === 'message') {
                if (isset($output_item['content']) && is_array($output_item['content'])) {
                    foreach ($output_item['content'] as $content_block) {
                        if (isset($content_block['annotations']) && is_array($content_block['annotations'])) {
                            foreach ($content_block['annotations'] as $annotation) {
                                if (isset($annotation['filename'])) {
                                    $filename = $annotation['filename'];
                                    $score = $annotation['score'] ?? 0;
                                    $text_content = '';

                                    if (isset($annotation['content']) && is_array($annotation['content'])) {
                                        foreach ($annotation['content'] as $ann_content) {
                                            if (isset($ann_content['text'])) {
                                                $text_content .= $ann_content['text'] . "\n";
                                            }
                                        }
                                    }

                                    if (!empty($text_content) && $matches_used < $max_results) {
                                        $content .= "## Reference " . ($matches_used + 1) . " ##\n";
                                        $content .= trim($text_content) . "\n\n";
                                        $content .= "Source: " . $filename . "\n\n";

                                        preg_match_all(
                                            '#\bhttps?://[^\s<>"\']+#i',
                                            $text_content,
                                            $content_urls
                                        );
                                        if (!empty($content_urls[0])) {
                                            $valid_urls = array_merge($valid_urls, $content_urls[0]);
                                        }

                                        $matches_used++;

                                        $all_matches[] = [
                                            'document_id' => $filename,
                                            'similarity' => $score,
                                            'similarity_percentage' => round($score * 100, 2),
                                            'above_threshold' => true,
                                            'source_display' => $filename,
                                            'content_preview' => substr(strip_tags($text_content), 0, 100) . '...',
                                            'used_for_context' => true,
                                            'role_restriction' => 'public',
                                            'has_access' => true,
                                            'filtered_out' => false
                                        ];
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }

    // Store for testing panel
    $this->last_similarity_analysis['top_matches'] = $all_matches;
    $this->last_similarity_analysis['total_checked'] = count($all_matches);

    // Store unique valid URLs for validation
    $this->current_valid_urls = array_unique($valid_urls);

    // Allow add-ons to act on similarity results (e.g. WooCommerce product card display)
    do_action('mxchat_similarity_results', $this->last_similarity_analysis['top_matches'], $bot_id);

    //error_log("MXCHAT VECTORSTORE: ========== SEARCH COMPLETE ==========");
    //error_log("MXCHAT VECTORSTORE: Matches used: " . $matches_used);
    //error_log("MXCHAT VECTORSTORE: All matches count: " . count($all_matches));
    //error_log("MXCHAT VECTORSTORE: Content length: " . strlen($content));
    if ($matches_used > 0) {
        //error_log("MXCHAT VECTORSTORE: Content preview: " . substr($content, 0, 500));
    }

    // Check if citation links are enabled
    $citation_links_enabled = ($mxchat_options['citation_links_toggle'] ?? 'on') === 'on';

    // Add response guidelines
    if ($matches_used === 0) {
        //error_log("MXCHAT VECTORSTORE: No matches found - returning empty reference message");
        $content = "No reference information was found for this query.\n\n";
    } else {
        // Build response guidelines based on citation links setting
        $content .= "\n## Response Guidelines ##\n" .
                   "You are an AI Chatbot. Answer naturally and helpfully using only the information from the references above. " .
                   "Be conversational and friendly, but never mention your knowledge base or training data. " .
                   "If you don't have specific information or are uncertain about any details, it's always " .
                   "better to honestly say you don't know rather than making up or guessing at answers. " .
                   "When information is incomplete, let them know you are unsure.\n\n";

        // Only add hyperlink instructions if citation links are enabled
        if ($citation_links_enabled) {
            $content .= "CRITICAL: When creating hyperlinks, always use proper markdown format with descriptive text: " .
                       "[descriptive text](url). NEVER use empty brackets like [](url). The text in brackets must describe what the link is about.";
        } else {
            $content .= "IMPORTANT: Do not include any citation links, source URLs, or hyperlinks in your responses. " .
                       "Simply provide helpful answers based on the reference information without citing sources.";
        }
    }

    //error_log("MXCHAT DEBUG: Vector Store search complete. Matches used: " . $matches_used);

    return trim($content);
}

/**
 * Check if the given model is an OpenAI chat model
 *
 * @param string $model The model ID
 * @return bool True if it's an OpenAI model
 */
private function is_openai_chat_model($model) {
    $openai_prefixes = array('gpt-', 'o1-', 'o3-');
    foreach ($openai_prefixes as $prefix) {
        if (strpos($model, $prefix) === 0) {
            return true;
        }
    }
    return false;
}

/**
 * Get bot-specific Vector Store configuration
 *
 * @param string $bot_id The bot ID
 * @return array Configuration array
 */
private function get_bot_vectorstore_config($bot_id = 'default') {
    // Admin Testing tab bot → resolve the DEFAULT bot's backend (see
    // get_bot_pinecone_config). This getter already passes the real default
    // config into the filter, so it was not broken — normalized anyway so the
    // Testing bot can never drift from the front-end default.
    if ($bot_id === 'testing') {
        $bot_id = 'default';
    }

    $vectorstore_options = get_option('mxchat_openai_vectorstore_options', array());

    // Default global settings
    $default_config = array(
        'use_vectorstore' => ($vectorstore_options['mxchat_use_openai_vectorstore'] ?? '0') === '1',
        'vectorstore_ids' => $vectorstore_options['mxchat_vectorstore_ids'] ?? '',
        'max_results' => $vectorstore_options['mxchat_vectorstore_max_results'] ?? 5
    );

    // Allow multi-bot plugin to override with bot-specific settings
    $bot_config = apply_filters('mxchat_get_bot_vectorstore_config', $default_config, $bot_id);

    // Preserve max_results from global settings if not set in bot config
    if (!isset($bot_config['max_results'])) {
        $bot_config['max_results'] = $default_config['max_results'];
    }

    return $bot_config;
}

private function mxchat_find_relevant_products($user_embedding) {
    //error_log('MXChat Vector Search: Starting product search...');

    // Retrieve the add-on settings from the database
    $addon_options = get_option('mxchat_pinecone_addon_options', array());

    // Determine whether Pinecone is enabled
    $use_pinecone = (isset($addon_options['mxchat_use_pinecone']) && $addon_options['mxchat_use_pinecone'] === '1') ? 1 : 0;

    //error_log('Pinecone enabled flag: ' . $use_pinecone);

    if ($use_pinecone === 1) {
        //error_log('MXChat Vector Search: Using Pinecone database for products');
        return $this->find_relevant_products_pinecone($user_embedding);
    } else {
        //error_log('MXChat Vector Search: Using WordPress database for products');
        return $this->find_relevant_products_wordpress($user_embedding);
    }
}
private function find_relevant_products_wordpress($user_embedding) {
    global $wpdb;
    $system_prompt_table = $wpdb->prefix . 'mxchat_system_prompt_content';

    if (!is_array($user_embedding)) {
        return '';
    }

    // Streaming top-K pass: scan rows in small batches, keep only the top 3
    // results above the similarity threshold. Peak memory is bounded by
    // $batch_size embedding rows plus a 3-element top list.
    $batch_size = 250;
    $similarity_threshold = 0.85;
    $top_k = 3;
    $top_results = [];
    $offset = 0;

    do {
        $batch = $wpdb->get_results($wpdb->prepare(
            "SELECT id, embedding_vector
             FROM {$system_prompt_table}
             LIMIT %d OFFSET %d",
            $batch_size,
            $offset
        ));

        if (empty($batch)) {
            break;
        }

        foreach ($batch as $row) {
            $database_embedding = $row->embedding_vector
                ? unserialize($row->embedding_vector, ['allowed_classes' => false])
                : null;

            if (!is_array($database_embedding)) {
                unset($database_embedding);
                continue;
            }

            $similarity = $this->mxchat_calculate_cosine_similarity($user_embedding, $database_embedding);
            unset($database_embedding);

            if ($similarity < $similarity_threshold) {
                continue;
            }

            // Insert into bounded top-K (kept sorted descending)
            if (count($top_results) < $top_k) {
                $top_results[] = ['id' => $row->id, 'similarity' => $similarity];
                usort($top_results, function ($a, $b) {
                    return $b['similarity'] <=> $a['similarity'];
                });
            } elseif ($similarity > $top_results[$top_k - 1]['similarity']) {
                $top_results[$top_k - 1] = ['id' => $row->id, 'similarity' => $similarity];
                usort($top_results, function ($a, $b) {
                    return $b['similarity'] <=> $a['similarity'];
                });
            }
        }

        unset($batch);
        $offset += $batch_size;
    } while (true);

    if (empty($top_results)) {
        return '';
    }

    $content = '';
    foreach ($top_results as $result) {
        $chunk_content = $this->fetch_content_with_product_links($result['id']);
        $content .= $chunk_content . "\n\n";
    }

    return trim($content);
}


private function find_relevant_products_pinecone($user_embedding) {
    //error_log('Starting Pinecone product search...');

    $options = get_option('mxchat_pinecone_addon_options', array());
    $api_key = $options['mxchat_pinecone_api_key'] ?? '';
    $host = $options['mxchat_pinecone_host'] ?? '';

    if (empty($host) || empty($api_key)) {
        //error_log('Pinecone credentials not properly configured for product search');
        return '';
    }

    $similarity_threshold = 0.85;
    $api_endpoint = "https://{$host}/query";

    $request_body = array(
        'vector' => $user_embedding,
        'topK' => 5,
        'includeMetadata' => true,
        'includeValues' => true,
        'filter' => array(
            'type' => 'product'
        )
    );

    //error_log('Sending request to Pinecone with body: ' . wp_json_encode($request_body));

    $response = wp_remote_post($api_endpoint, array(
        'headers' => array(
            'Api-Key' => $api_key,
            'accept' => 'application/json',
            'content-type' => 'application/json'
        ),
        'body' => wp_json_encode($request_body),
        'timeout' => 30
    ));

    if (is_wp_error($response)) {
        //error_log('Pinecone product query error: ' . $response->get_error_message());
        return '';
    }

    $response_code = wp_remote_retrieve_response_code($response);
    //error_log('Pinecone response code: ' . $response_code);

    if ($response_code !== 200) {
        //error_log('Pinecone API error during product search: ' . wp_remote_retrieve_body($response));
        return '';
    }

    $results = json_decode(wp_remote_retrieve_body($response), true);
    //error_log('Pinecone raw response: ' . wp_remote_retrieve_body($response));

    if (empty($results['matches'])) {
        //error_log('No matches found in Pinecone response');
        return '';
    }

    $content = '';
    foreach ($results['matches'] as $match) {
        if ($match['score'] < $similarity_threshold) {
            //error_log("Match below threshold: " . $match['score']);
            continue;
        }

        if (!empty($match['metadata']['text'])) {
            $content .= $match['metadata']['text'];
            if (!empty($match['metadata']['source_url'])) {
                $content .= "\n\nFor more details, check out this product: " . esc_url($match['metadata']['source_url']);
            }
            $content .= "\n\n";
        }
    }

    return trim($content);
}


private function fetch_content_with_product_links($most_relevant_id) {
    global $wpdb;
    $system_prompt_table = $wpdb->prefix . 'mxchat_system_prompt_content';

    // Fetch the article content and associated product URL
    $query = $wpdb->prepare("SELECT article_content, source_url FROM {$system_prompt_table} WHERE id = %d", $most_relevant_id);
    $result = $wpdb->get_row($query);

    if ($result) {
        // Append the product link to the content if available
        $content = $result->article_content;
        if (!empty($result->source_url)) {
            $content .= "\n\nFor more details, check out this product: " . esc_url($result->source_url);
        }
        return $content;
    }

    return null;
}

/**
 * Get system instructions for a specific bot or default
 * Checks for multi-bot add-on and uses bot-specific instructions if available
 * Automatically strips URLs if citation links are disabled
 * Replaces {visitor_name} placeholder with actual visitor name if available
 *
 * @param string $bot_id The bot ID to get instructions for
 * @param string $session_id Optional session ID to lookup visitor name
 */
private function get_system_instructions($bot_id = 'default', $session_id = '') {
    $instructions = '';

    // Check if multi-bot add-on is active
    if (class_exists('MxChat_Multi_Bot_Core_Manager') && $bot_id !== 'default') {
        // Get bot-specific options from multi-bot add-on
        $bot_options = apply_filters('mxchat_get_bot_options', array(), $bot_id);

        // If bot has custom system instructions, use those
        if (!empty($bot_options['system_prompt_instructions'])) {
            $instructions = $bot_options['system_prompt_instructions'];
        }
    }

    // Fall back to default system instructions
    if (empty($instructions)) {
        $instructions = isset($this->options['system_prompt_instructions']) ? $this->options['system_prompt_instructions'] : '';
    }

    // Check if citation links are disabled - if so, strip URLs from instructions
    $fresh_options = get_option('mxchat_options', []);
    $citation_links_enabled = isset($fresh_options['citation_links_toggle']) ? ($fresh_options['citation_links_toggle'] === 'on') : true;

    if (!$citation_links_enabled && !empty($instructions)) {
        $instructions = preg_replace('#\bhttps?://[^\s<>"\']+#i', '', $instructions);
        $instructions = preg_replace('/\s+/', ' ', trim($instructions)); // Clean up extra spaces
    }

    // Replace {visitor_name} placeholder with actual visitor name if available
    if (!empty($instructions) && !empty($session_id) && stripos($instructions, '{visitor_name}') !== false) {
        $name_option_key = "mxchat_name_{$session_id}";
        $visitor_name = get_option($name_option_key, '');

        if (!empty($visitor_name)) {
            $instructions = str_ireplace('{visitor_name}', sanitize_text_field($visitor_name), $instructions);
        } else {
            // Remove placeholder if no name is available
            $instructions = str_ireplace('{visitor_name}', '', $instructions);
            $instructions = preg_replace('/\s{2,}/', ' ', trim($instructions)); // Clean up extra spaces
        }
    }

    // {context} placeholder (plan 59bc1b): inject the assembled knowledge-base
    // block where the owner placed the token. Runs after the URL-strip and
    // {visitor_name} handling and before the developer filter, so filtered
    // instructions already show the final prompt. Only active once the KB
    // assembly has stashed the block (context_kb_block non-null) — the early
    // URL-extraction call happens before assembly and leaves the token alone.
    if ($this->context_kb_block !== null && !empty($instructions) && stripos($instructions, '{context}') !== false) {
        $pos = stripos($instructions, '{context}');
        $instructions = substr($instructions, 0, $pos)
            . rtrim($this->context_kb_block) . "\n"
            . substr($instructions, $pos + strlen('{context}'));
        // Additional occurrences are stripped — never duplicate the KB block.
        $instructions = str_ireplace('{context}', '', $instructions);
    }

    // Allow developers to filter system instructions and process shortcodes
    $instructions = apply_filters('mxchat_system_instructions', $instructions, $bot_id, $session_id);
    $instructions = do_shortcode($instructions);

    return $instructions;
}
/**
 * Get the current bot ID from session or request context
 */
private function get_current_bot_id($session_id = '') {
    // First, check if bot_id is passed in the current request
    if (isset($_POST['bot_id']) && !empty($_POST['bot_id'])) {
        return sanitize_key($_POST['bot_id']);
    }
    
    // If not in POST, try to get it from session data
    if (!empty($session_id)) {
        $bot_id = get_option("mxchat_session_bot_{$session_id}", '');
        if (!empty($bot_id)) {
            return $bot_id;
        }
    }
    
    // Fall back to default
    return 'default';
}
/* ====================================================================== *
 *  Native function-calling loop (plan-mxchat-20260617-a41dee)
 *
 *  Model-driven tool use. The model is offered MxChat's enabled callbacks as
 *  tools (sourced from MxChat_Tool_Registry, the single source the admin AI
 *  Tools checklist also reads). When the model calls a tool, the matching
 *  callback runs through its EXISTING permission checks, its output is fed
 *  back, and the loop continues up to a depth cap. INDEPENDENT of the
 *  intent→callback router — it runs only after intents miss, and works with
 *  ZERO Actions created.
 *
 *  Entered ONLY when: function calling is enabled + the active model is
 *  tool-capable + at least one tool is enabled. Default-off, so existing
 *  installs never enter this branch (byte-for-byte unchanged behavior). The
 *  tool round is buffered (non-streaming) per the plan; the final answer is
 *  emitted via the same SSE/JSON envelopes the normal path uses.
 * ====================================================================== */

/** Gate: should the function-calling loop handle this turn? */
private function mxchat_fc_should_run($selected_model) {
    if (!class_exists('MxChat_Tool_Registry') || !MxChat_Tool_Registry::is_enabled()) {
        return false;
    }
    if (class_exists('MxChat_Model_Catalog') && !MxChat_Model_Catalog::supports_tools($selected_model)) {
        return false;
    }
    $tools = MxChat_Tool_Registry::enabled_tools();
    return !empty($tools);
}

private function mxchat_fc_log($msg) {
    if (defined('MXCHAT_DEV_MODE') && MXCHAT_DEV_MODE) {
        error_log('[MxChat FC] ' . $msg);
    }
}

/**
 * Resolve provider transport details. Returns null when FC can't run for this
 * model/config (missing key, unsupported provider) so the caller falls back to
 * the normal path. OpenAI/xAI/DeepSeek/OpenRouter/Custom share the
 * OpenAI-compatible 'openai' family; Claude and Gemini are distinct.
 */
private function mxchat_fc_resolve_provider($selected_model, $opts) {
    // Anthropic retired claude-opus-4-20250514 / claude-sonnet-4-20250514 on 2026-06-15.
    // Read-time rescue: remap a saved dead ID to the current equivalent before the API call.
    if ($selected_model === 'claude-opus-4-20250514') { $selected_model = 'claude-opus-4-8'; }
    elseif ($selected_model === 'claude-sonnet-4-20250514') { $selected_model = 'claude-sonnet-4-6'; }
    if ($selected_model === 'openrouter') {
        $model = isset($opts['openrouter_selected_model']) ? $opts['openrouter_selected_model'] : '';
        $key   = isset($opts['openrouter_api_key']) ? $opts['openrouter_api_key'] : '';
        if ($model === '' || $key === '') return null;
        return array('family'=>'openai','model'=>$model,'url'=>'https://openrouter.ai/api/v1/chat/completions',
            'headers'=>array('Content-Type'=>'application/json','Authorization'=>'Bearer '.$key),'tag'=>'openai');
    }
    $prefix = strtolower(explode('-', $selected_model)[0]);
    switch ($prefix) {
        case 'gpt': case 'o1': case 'o3': case 'o4':
            $key = isset($opts['api_key']) ? $opts['api_key'] : '';
            if ($key === '') return null;
            return array('family'=>'openai','model'=>$selected_model,'url'=>'https://api.openai.com/v1/chat/completions',
                'headers'=>array('Content-Type'=>'application/json','Authorization'=>'Bearer '.$key),'tag'=>'openai');
        case 'claude':
            $key = isset($opts['claude_api_key']) ? $opts['claude_api_key'] : '';
            if ($key === '') return null;
            return array('family'=>'anthropic','model'=>$selected_model,'url'=>'https://api.anthropic.com/v1/messages',
                'headers'=>array('Content-Type'=>'application/json','x-api-key'=>$key,'anthropic-version'=>'2023-06-01'),'tag'=>'anthropic');
        case 'gemini':
            $key = isset($opts['gemini_api_key']) ? $opts['gemini_api_key'] : '';
            if ($key === '') return null;
            return array('family'=>'gemini','model'=>$selected_model,'key'=>$key,'tag'=>'gemini');
        case 'grok': case 'xai':
            $key = isset($opts['xai_api_key']) ? $opts['xai_api_key'] : '';
            if ($key === '') return null;
            return array('family'=>'openai','model'=>$selected_model,'url'=>'https://api.x.ai/v1/chat/completions',
                'headers'=>array('Content-Type'=>'application/json','Authorization'=>'Bearer '.$key),'tag'=>'xai');
        case 'deepseek':
            $key = isset($opts['deepseek_api_key']) ? $opts['deepseek_api_key'] : '';
            if ($key === '') return null;
            return array('family'=>'openai','model'=>$selected_model,'url'=>'https://api.deepseek.com/v1/chat/completions',
                'headers'=>array('Content-Type'=>'application/json','Authorization'=>'Bearer '.$key),'tag'=>'openai');
        case 'custom':
            $base  = isset($opts['custom_provider_base_url']) ? rtrim($opts['custom_provider_base_url'], '/') : '';
            $key   = isset($opts['custom_provider_api_key']) ? $opts['custom_provider_api_key'] : '';
            $model = isset($opts['custom_provider_model']) ? $opts['custom_provider_model'] : '';
            if ($base === '' || $model === '') return null;
            $url = (strpos($base, 'chat/completions') !== false) ? $base : $base . '/chat/completions';
            $headers = array('Content-Type'=>'application/json');
            if ($key !== '') $headers['Authorization'] = 'Bearer '.$key;
            return array('family'=>'openai','model'=>$model,'url'=>$url,'headers'=>$headers,'tag'=>'openai');
    }
    return null;
}

/**
 * Top-level function-calling attempt. Returns:
 *   ['handled'=>true,  'text'=>'']  when the model used ≥1 tool
 *   ['handled'=>false]                            otherwise (caller falls back
 *                                                 to the normal streamed path)
 */
private function mxchat_fc_attempt($message, $relevant_content, $conversation_history, $selected_model, $opts, $session_id, $user_id) {
    $prov = $this->mxchat_fc_resolve_provider($selected_model, $opts);
    if (!$prov) {
        return array('handled' => false);
    }
    $tools = MxChat_Tool_Registry::enabled_tools();
    if (empty($tools)) {
        return array('handled' => false);
    }

    $bot_id = $this->get_current_bot_id($session_id);
    $system = $this->get_system_instructions($bot_id, $session_id);

    // Force callbacks into return-mode (some echo SSE directly when streaming);
    // we buffer the whole tool round, then emit once. Restored in finally.
    $prev_streaming = $this->is_streaming;
    $this->is_streaming = false;
    try {
        if ($prov['family'] === 'anthropic') {
            return $this->mxchat_fc_loop_anthropic($prov, $system, $relevant_content, $conversation_history, $tools, $message, $user_id, $session_id);
        } elseif ($prov['family'] === 'gemini') {
            return $this->mxchat_fc_loop_gemini($prov, $system, $relevant_content, $conversation_history, $tools, $message, $user_id, $session_id);
        }
        return $this->mxchat_fc_loop_openai($prov, $system, $relevant_content, $conversation_history, $tools, $message, $user_id, $session_id);
    } catch (\Throwable $e) {
        $this->mxchat_fc_log('attempt threw: ' . $e->getMessage());
        return array('handled' => false);
    } finally {
        $this->is_streaming = $prev_streaming;
    }
}

/** Normalize MxChat history rows to [{role:user|assistant, content}]. */
private function mxchat_fc_normalize_history($conversation_history) {
    $out = array();
    if (!is_array($conversation_history)) return $out;
    foreach ($conversation_history as $m) {
        if (!is_array($m) || !isset($m['role']) || !isset($m['content'])) continue;
        $role = $m['role'];
        if ($role === 'bot' || $role === 'agent') $role = 'assistant';
        if (!in_array($role, array('user', 'assistant'), true)) $role = 'user';
        $out[] = array('role' => $role, 'content' => (string) $m['content']);
    }
    return $out;
}

/** Execute the matched callback for a tool call. Returns ['ok'=>bool,'content'=>string]. */
private function mxchat_fc_execute_tool($tool_name, $args, $orig_message, $user_id, $session_id) {
    $tool = MxChat_Tool_Registry::tool_by_name($tool_name, true); // enabled-only
    if (!$tool) {
        return array('ok' => false, 'content' => 'This tool is not available or not enabled.');
    }
    $fn = $tool['callback'];

    // MxChat callbacks are message-driven: hand them the model's `query`
    // (falling back to the original user message).
    $query = '';
    if (is_array($args) && isset($args['query']) && is_string($args['query'])) {
        $query = $args['query'];
    }
    if ($query === '') $query = $orig_message;

    // Synthetic intent row (matches wp_mxchat_intents columns → no undefined-prop warnings).
    $synthetic_intent = (object) array(
        'id' => 0, 'intent_label' => $tool['label'], 'phrases' => '',
        'embedding_vector' => '', 'callback_function' => $fn,
        'similarity_threshold' => 0.0, 'enabled' => 1, 'enabled_bots' => null,
    );

    try {
        if (!empty($tool['is_addon'])) {
            $result = apply_filters($fn, false, $query, $user_id, $session_id, $synthetic_intent);
        } elseif (method_exists($this, $fn)) {
            $result = call_user_func(array($this, $fn), $query, $user_id, $session_id, $synthetic_intent, null);
        } else {
            return array('ok' => false, 'content' => 'Tool implementation not found.');
        }
    } catch (\Throwable $e) {
        $this->mxchat_fc_log("tool {$fn} threw: " . $e->getMessage());
        return array('ok' => false, 'content' => 'The tool failed to run.');
    }

    // plan-mxchat-20260617-48a57a — surface UI-bearing tool output.
    // If the callback produced a UI element (generated image, product card, image
    // gallery), its html MUST reach the FRONTEND as a real rendered bot message —
    // NOT be stripped to text and handed to the model to paraphrase (that was the
    // bug: under function calling, UI-bearing actions rendered nothing). Capture
    // the html here; the FC outcome handler emits it in the response envelope.
    $ui = $this->mxchat_fc_ui_payload_from($result);
    if ($ui['html'] !== '' || !empty($ui['images'])) {
        if ($ui['html'] !== '') {
            $this->fc_ui_html .= ($this->fc_ui_html !== '' ? "\n" : '') . $ui['html'];
        }
        if (!empty($ui['images']) && is_array($ui['images'])) {
            $this->fc_ui_images = array_merge($this->fc_ui_images, $ui['images']);
        }
        $this->fc_ui_captured = true;

        // Persist the html to the transcript ONLY if the callback did not already
        // do so itself. Core image/search callbacks self-save (text + html);
        // add-on callbacks (e.g. woo product cards) return html for the caller to
        // save. ui_self_saves carries this from the registry; default by source
        // (core self-saves, add-on does not) when a tool predates the flag.
        $self_saves = array_key_exists('ui_self_saves', $tool)
            ? !empty($tool['ui_self_saves'])
            : empty($tool['is_addon']);
        if ($ui['html'] !== '' && !$self_saves) {
            $this->mxchat_save_chat_message($session_id, 'bot', $ui['html']);
        }

        // Hand the MODEL a short acknowledgment (never the raw or stripped html)
        // so the loop can add a one-line caption without trying to re-describe a
        // visual it cannot see and without duplicating the displayed element.
        $summary = isset($ui['text']) ? trim((string) $ui['text']) : '';
        $ack = __('[A visual result has already been shown to the user in the chat. Do not repeat or describe it in detail — reply with at most a brief one-line caption.]', 'mxchat');
        $content = $summary !== '' ? ($ack . ' ' . $summary) : $ack;
        $this->mxchat_fc_log("executed {$fn} → [ui payload surfaced] " . substr($content, 0, 120));
        return array('ok' => true, 'content' => $content);
    }

    $content = $this->mxchat_fc_stringify_result($result);
    $this->mxchat_fc_log("executed {$fn} → " . substr($content, 0, 160));
    return array('ok' => true, 'content' => $content);
}

/**
 * Extract a UI payload (html + images + text) from a tool callback's return,
 * falling back to $this->fallbackResponse for callbacks that return true after
 * setting it. plan-mxchat-20260617-48a57a.
 *
 * @return array{html:string,images:array,text:string}
 */
private function mxchat_fc_ui_payload_from($result) {
    $src = null;
    if (is_array($result)) {
        $src = $result;
    } elseif ($result === true && isset($this->fallbackResponse) && is_array($this->fallbackResponse)) {
        $src = $this->fallbackResponse;
    }
    $html   = (is_array($src) && isset($src['html']) && is_string($src['html'])) ? $src['html'] : '';
    $images = (is_array($src) && isset($src['images']) && is_array($src['images'])) ? $src['images'] : array();
    $text   = (is_array($src) && isset($src['text'])) ? (string) $src['text'] : '';
    return array('html' => $html, 'images' => $images, 'text' => $text);
}

/** Coerce a callback's return (string|array|true|false) into a tool-result string. */
private function mxchat_fc_stringify_result($result) {
    if (is_string($result)) {
        return $result === '' ? 'No result.' : $result;
    }
    if ($result === true) {
        // Callbacks that set fallbackResponse and return true.
        $fb = isset($this->fallbackResponse) ? $this->fallbackResponse : null;
        if (is_array($fb)) {
            if (!empty($fb['text'])) return (string) $fb['text'];
            if (!empty($fb['html'])) return wp_strip_all_tags((string) $fb['html']);
        }
        return 'Done.';
    }
    if ($result === false || $result === null) {
        return 'No result.';
    }
    if (is_array($result)) {
        if (isset($result['text']) && $result['text'] !== '') return (string) $result['text'];
        if (isset($result['html']) && $result['html'] !== '') return wp_strip_all_tags((string) $result['html']);
        $json = wp_json_encode($result);
        return $json !== false ? $json : 'No result.';
    }
    return (string) $result;
}

/** HTTP code + decoded body for a function-calling request. */
private function mxchat_fc_post($url, $body, $headers, $tag) {
    $args = array(
        'body' => wp_json_encode($body),
        'headers' => $headers,
        'timeout' => 60,
        'redirection' => 5,
        'blocking' => true,
        'httpversion' => '1.0',
        'sslverify' => true,
    );
    $response = $this->mxchat_provider_call_with_retry($url, $args, $tag);
    if (is_wp_error($response)) {
        return array('code' => 0, 'data' => null, 'error' => $response->get_error_message());
    }
    $code = (int) wp_remote_retrieve_response_code($response);
    $data = json_decode(wp_remote_retrieve_body($response), true);
    return array('code' => $code, 'data' => $data, 'error' => null);
}

/* ---------------- OpenAI-compatible loop (OpenAI/xAI/DeepSeek/OpenRouter/Custom) -------------- */
private function mxchat_fc_loop_openai($prov, $system, $relevant_content, $conversation_history, $tools, $orig_message, $user_id, $session_id) {
    $messages = array();
    $messages[] = array('role' => 'system', 'content' => $system . ' ' . $relevant_content);
    foreach ($this->mxchat_fc_normalize_history($conversation_history) as $m) {
        $messages[] = $m;
    }

    $depth = MxChat_Tool_Registry::max_depth();
    $budget = MxChat_Tool_Registry::max_tool_calls_per_turn();
    $tool_schema = MxChat_Tool_Registry::to_openai_tools($tools);
    $used_tool = false;
    $calls_made = 0;

    for ($step = 0; $step <= $depth; $step++) {
        $offer_tools = ($step < $depth) && !empty($tool_schema);
        $body = array('model' => $prov['model'], 'messages' => $messages, 'temperature' => 1, 'stream' => false);
        if (strpos($prov['url'], 'api.deepseek.com') !== false) {
            // DeepSeek V4 defaults to thinking mode ON; tool loops want fast
            // deterministic non-thinking turns (legacy deepseek-chat semantics).
            $body['thinking'] = array('type' => 'disabled');
        }
        if ($offer_tools) {
            $body['tools'] = $tool_schema;
            $body['tool_choice'] = 'auto';
        }
        $r = $this->mxchat_fc_post($prov['url'], $body, $prov['headers'], $prov['tag']);
        if ($r['code'] !== 200 || !is_array($r['data'])) {
            $this->mxchat_fc_log('openai call failed: code=' . $r['code'] . ' err=' . ($r['error'] ?? ''));
            return $used_tool ? array('handled' => true, 'text' => $this->mxchat_fc_giveup_text()) : array('handled' => false);
        }
        $msg = isset($r['data']['choices'][0]['message']) ? $r['data']['choices'][0]['message'] : null;
        if (!$msg) {
            return $used_tool ? array('handled' => true, 'text' => $this->mxchat_fc_giveup_text()) : array('handled' => false);
        }
        $tool_calls = isset($msg['tool_calls']) && is_array($msg['tool_calls']) ? $msg['tool_calls'] : array();
        if (empty($tool_calls)) {
            $text = isset($msg['content']) ? trim((string) $msg['content']) : '';
            if (!$used_tool) return array('handled' => false);          // model never used a tool → normal path
            return array('handled' => true, 'text' => ($text !== '' ? $text : $this->mxchat_fc_giveup_text()));
        }
        // Append the assistant tool-call turn verbatim, then a tool result per call.
        $used_tool = true;
        $messages[] = $msg;
        foreach ($tool_calls as $tc) {
            if ($calls_made >= $budget) break;
            $calls_made++;
            $name = isset($tc['function']['name']) ? $tc['function']['name'] : '';
            $args = array();
            if (isset($tc['function']['arguments'])) {
                $decoded = json_decode($tc['function']['arguments'], true);
                if (is_array($decoded)) $args = $decoded;
            }
            $exec = $this->mxchat_fc_execute_tool($name, $args, $orig_message, $user_id, $session_id);
            $messages[] = array(
                'role' => 'tool',
                'tool_call_id' => isset($tc['id']) ? $tc['id'] : '',
                'content' => $exec['content'],
            );
        }
    }
    return $used_tool ? array('handled' => true, 'text' => $this->mxchat_fc_giveup_text()) : array('handled' => false);
}

/* ---------------- Anthropic Claude loop ---------------- */
private function mxchat_fc_loop_anthropic($prov, $system, $relevant_content, $conversation_history, $tools, $orig_message, $user_id, $session_id) {
    $messages = $this->mxchat_fc_normalize_history($conversation_history);
    $messages[] = array('role' => 'user', 'content' => $relevant_content);

    $depth = MxChat_Tool_Registry::max_depth();
    $budget = MxChat_Tool_Registry::max_tool_calls_per_turn();
    $tool_schema = MxChat_Tool_Registry::to_anthropic_tools($tools);
    $omit_temp = $this->mxchat_claude_omits_temperature($prov['model']);
    $used_tool = false;
    $calls_made = 0;

    for ($step = 0; $step <= $depth; $step++) {
        $offer_tools = ($step < $depth) && !empty($tool_schema);
        $body = array('model' => $prov['model'], 'max_tokens' => 1024, 'temperature' => 0.8,
                      'messages' => $messages, 'system' => $system);
        if ($omit_temp) unset($body['temperature']);
        if ($offer_tools) {
            $body['tools'] = $tool_schema;
            $body['tool_choice'] = array('type' => 'auto');
        }
        $r = $this->mxchat_fc_post($prov['url'], $body, $prov['headers'], $prov['tag']);
        if ($r['code'] !== 200 || !is_array($r['data'])) {
            $this->mxchat_fc_log('anthropic call failed: code=' . $r['code'] . ' err=' . ($r['error'] ?? ''));
            return $used_tool ? array('handled' => true, 'text' => $this->mxchat_fc_giveup_text()) : array('handled' => false);
        }
        $content = isset($r['data']['content']) && is_array($r['data']['content']) ? $r['data']['content'] : array();
        $tool_uses = array();
        $text_out = '';
        foreach ($content as $block) {
            if (!isset($block['type'])) continue;
            if ($block['type'] === 'tool_use') {
                $tool_uses[] = $block;
            } elseif ($block['type'] === 'text' && isset($block['text'])) {
                $text_out .= $block['text'];
            }
        }
        if (empty($tool_uses)) {
            if (!$used_tool) return array('handled' => false);
            $text_out = trim($text_out);
            return array('handled' => true, 'text' => ($text_out !== '' ? $text_out : $this->mxchat_fc_giveup_text()));
        }
        // Append the assistant turn (the full content array), then a user turn of tool_result blocks.
        $used_tool = true;
        $messages[] = array('role' => 'assistant', 'content' => $content);
        $results = array();
        foreach ($tool_uses as $tu) {
            if ($calls_made >= $budget) break;
            $calls_made++;
            $name = isset($tu['name']) ? $tu['name'] : '';
            $args = isset($tu['input']) && is_array($tu['input']) ? $tu['input'] : array();
            $exec = $this->mxchat_fc_execute_tool($name, $args, $orig_message, $user_id, $session_id);
            $results[] = array(
                'type' => 'tool_result',
                'tool_use_id' => isset($tu['id']) ? $tu['id'] : '',
                'content' => $exec['content'],
            );
        }
        $messages[] = array('role' => 'user', 'content' => $results);
    }
    return $used_tool ? array('handled' => true, 'text' => $this->mxchat_fc_giveup_text()) : array('handled' => false);
}

/* ---------------- Google Gemini loop ---------------- */
private function mxchat_fc_loop_gemini($prov, $system, $relevant_content, $conversation_history, $tools, $orig_message, $user_id, $session_id) {
    $contents = array();
    $contents[] = array('role' => 'user',  'parts' => array(array('text' => '[System Instructions] ' . $system . ' ' . $relevant_content)));
    $contents[] = array('role' => 'model', 'parts' => array(array('text' => 'I understand and will follow these instructions.')));
    foreach ($this->mxchat_fc_normalize_history($conversation_history) as $m) {
        $contents[] = array('role' => ($m['role'] === 'assistant' ? 'model' : 'user'),
                            'parts' => array(array('text' => $m['content'])));
    }

    $depth = MxChat_Tool_Registry::max_depth();
    $budget = MxChat_Tool_Registry::max_tool_calls_per_turn();
    $tool_schema = MxChat_Tool_Registry::to_gemini_tools($tools);
    // Function calling (tools + functionDeclarations + toolConfig) is a v1beta feature on the
    // Generative Language REST API. The v1 endpoint silently ignores the tools array, so a
    // non-preview model (e.g. gemini-2.5-pro, gemini-3.5-flash, gemini-3.1-flash-lite) would
    // just answer in text and never emit a tool call. Always use v1beta for the FC loop —
    // confirmed against Google's function-calling docs (their REST example targets
    // v1beta/models/gemini-3.5-flash:generateContent). v1beta is a superset, so every model
    // reachable on v1 is also reachable here.
    $api_version = 'v1beta';
    $url = 'https://generativelanguage.googleapis.com/' . $api_version . '/models/' . $prov['model'] . ':generateContent?key=' . $prov['key'];
    $headers = array('Content-Type' => 'application/json');
    $used_tool = false;
    $calls_made = 0;

    for ($step = 0; $step <= $depth; $step++) {
        $offer_tools = ($step < $depth) && !empty($tool_schema);
        $body = array(
            'contents' => $contents,
            'generationConfig' => array('temperature' => 0.7, 'topP' => 0.95, 'topK' => 40, 'maxOutputTokens' => 8192),
        );
        if ($offer_tools) {
            $body['tools'] = $tool_schema;
            $body['toolConfig'] = array('functionCallingConfig' => array('mode' => 'AUTO'));
        }
        $r = $this->mxchat_fc_post($url, $body, $headers, 'gemini');
        if ($r['code'] !== 200 || !is_array($r['data']) || isset($r['data']['error'])) {
            $this->mxchat_fc_log('gemini call failed: code=' . $r['code'] . ' err=' . ($r['error'] ?? ''));
            return $used_tool ? array('handled' => true, 'text' => $this->mxchat_fc_giveup_text()) : array('handled' => false);
        }
        $parts = isset($r['data']['candidates'][0]['content']['parts']) && is_array($r['data']['candidates'][0]['content']['parts'])
            ? $r['data']['candidates'][0]['content']['parts'] : array();
        $fn_calls = array();
        $text_out = '';
        foreach ($parts as $p) {
            if (isset($p['functionCall'])) {
                $fn_calls[] = $p['functionCall'];
            } elseif (isset($p['text'])) {
                $text_out .= $p['text'];
            }
        }
        if (empty($fn_calls)) {
            if (!$used_tool) return array('handled' => false);
            $text_out = trim($text_out);
            return array('handled' => true, 'text' => ($text_out !== '' ? $text_out : $this->mxchat_fc_giveup_text()));
        }
        // Append the model turn (its parts) then a user turn of functionResponse parts.
        $used_tool = true;
        $contents[] = array('role' => 'model', 'parts' => $parts);
        $resp_parts = array();
        foreach ($fn_calls as $fcall) {
            if ($calls_made >= $budget) break;
            $calls_made++;
            $name = isset($fcall['name']) ? $fcall['name'] : '';
            $args = isset($fcall['args']) && is_array($fcall['args']) ? $fcall['args'] : array();
            $exec = $this->mxchat_fc_execute_tool($name, $args, $orig_message, $user_id, $session_id);
            $fr = array('name' => $name, 'response' => array('result' => $exec['content']));
            // Gemini 3 function calls carry a unique id; echo the matching id back in the
            // functionResponse so the model maps the result to the right call (Google REST
            // guidance). Older models omit the id — then we send none, exactly as before.
            if (isset($fcall['id']) && $fcall['id'] !== '') { $fr['id'] = $fcall['id']; }
            $resp_parts[] = array('functionResponse' => $fr);
        }
        $contents[] = array('role' => 'user', 'parts' => $resp_parts);
    }
    return $used_tool ? array('handled' => true, 'text' => $this->mxchat_fc_giveup_text()) : array('handled' => false);
}

private function mxchat_fc_giveup_text() {
    return esc_html__('I looked into that but could not put together a final answer. Please try rephrasing your request.', 'mxchat');
}

private function mxchat_generate_response($relevant_content, $api_key, $xai_api_key, $claude_api_key, $deepseek_api_key, $gemini_api_key, $openrouter_api_key, $conversation_history, $streaming = false, $session_id = '', $testing_data = null, $selected_model = 'gpt-5.1-chat-latest') {
    try {
        if (!$relevant_content) {
            $error_response = [
                'error' => esc_html__("I couldn't find relevant information on that topic.", 'mxchat'),
                'error_code' => 'no_relevant_content'
            ];
            
            if ($testing_data !== null) {
                $error_response['testing_data'] = $testing_data;
            }
            
            return $error_response;
        }
        
        if (!is_array($conversation_history)) {
            $conversation_history = array();
        }
        
        // Check if this is an OpenRouter model
        if ($selected_model === 'openrouter') {
            // Get the actual OpenRouter model from options
            $openrouter_selected_model = $this->options['openrouter_selected_model'] ?? '';
            
            if (empty($openrouter_selected_model)) {
                $error_response = [
                    'error' => esc_html__('No OpenRouter model selected. Please select a model in settings.', 'mxchat'),
                    'error_code' => 'no_openrouter_model_selected'
                ];
                if ($testing_data !== null) {
                    $error_response['testing_data'] = $testing_data;
                }
                return $error_response;
            }
            
            if (empty($openrouter_api_key)) {
                $error_response = [
                    'error' => esc_html__('OpenRouter API key is not configured', 'mxchat'),
                    'error_code' => 'missing_openrouter_api_key'
                ];
                if ($testing_data !== null) {
                    $error_response['testing_data'] = $testing_data;
                }
                return $error_response;
            }
            
            if ($streaming) {
                return $this->mxchat_generate_response_openrouter_stream(
                    $openrouter_selected_model,
                    $openrouter_api_key,
                    $conversation_history,
                    $relevant_content,
                    $session_id,
                    $testing_data
                );
            } else {
                $response = $this->mxchat_generate_response_openrouter(
                    $openrouter_selected_model,
                    $openrouter_api_key,
                    $conversation_history,
                    $relevant_content,
                    $session_id
                );
            }
            
            if (is_array($response) && isset($response['error'])) {
                if ($testing_data !== null) {
                    $response['testing_data'] = $testing_data;
                }
                return $response;
            }
            
            return $response;
        }

        // Extract model prefix to determine the provider
        $model_parts = explode('-', $selected_model);
        $provider = strtolower($model_parts[0]);
        
        // Handle model selection based on provider prefix
        switch ($provider) {
            case 'gemini':
                if (empty($gemini_api_key)) {
                    $error_response = [
                        'error' => esc_html__('Google Gemini API key is not configured', 'mxchat'),
                        'error_code' => 'missing_gemini_api_key'
                    ];
                    if ($testing_data !== null) {
                        $error_response['testing_data'] = $testing_data;
                    }
                    return $error_response;
                }
                $response = $this->mxchat_generate_response_gemini(
                    $selected_model,
                    $gemini_api_key,
                    $conversation_history,
                    $relevant_content,
                    $session_id
                );
                break;
                
            case 'claude':
                if (empty($claude_api_key)) {
                    $error_response = [
                        'error' => esc_html__('Claude API key is not configured', 'mxchat'),
                        'error_code' => 'missing_claude_api_key'
                    ];
                    if ($testing_data !== null) {
                        $error_response['testing_data'] = $testing_data;
                    }
                    return $error_response;
                }
                if ($streaming) {
                    return $this->mxchat_generate_response_claude_stream(
                        $selected_model,
                        $claude_api_key,
                        $conversation_history,
                        $relevant_content,
                        $session_id,
                        $testing_data
                    );
                } else {
                    $response = $this->mxchat_generate_response_claude(
                        $selected_model,
                        $claude_api_key,
                        $conversation_history,
                        $relevant_content,
                        $session_id
                    );
                }
                break;
                
            case 'grok':
                if (empty($xai_api_key)) {
                    $error_response = [
                        'error' => esc_html__('X.AI API key is not configured', 'mxchat'),
                        'error_code' => 'missing_xai_api_key'
                    ];
                    if ($testing_data !== null) {
                        $error_response['testing_data'] = $testing_data;
                    }
                    return $error_response;
                }
                if ($streaming) {
                    return $this->mxchat_generate_response_xai_stream(
                        $selected_model,
                        $xai_api_key,
                        $conversation_history,
                        $relevant_content,
                        $session_id,
                        $testing_data
                    );
                } else {
                    $response = $this->mxchat_generate_response_xai(
                        $selected_model,
                        $xai_api_key,
                        $conversation_history,
                        $relevant_content,
                        $session_id
                    );
                }
                break;
                
            case 'deepseek':
                if (empty($deepseek_api_key)) {
                    $error_response = [
                        'error' => esc_html__('DeepSeek API key is not configured', 'mxchat'),
                        'error_code' => 'missing_deepseek_api_key'
                    ];
                    if ($testing_data !== null) {
                        $error_response['testing_data'] = $testing_data;
                    }
                    return $error_response;
                }
                if ($streaming) {
                    return $this->mxchat_generate_response_deepseek_stream(
                        $selected_model,
                        $deepseek_api_key,
                        $conversation_history,
                        $relevant_content,
                        $session_id,
                        $testing_data
                    );
                } else {
                    $response = $this->mxchat_generate_response_deepseek(
                        $selected_model,
                        $deepseek_api_key,
                        $conversation_history,
                        $relevant_content,
                        $session_id
                    );
                }
                break;
                
            case 'custom':
                // Custom (OpenAI-compatible) provider — Ollama, LM Studio, vLLM, llama.cpp, Azure OpenAI
                $cp_base_url = isset($this->options['custom_provider_base_url']) ? trim((string) $this->options['custom_provider_base_url']) : '';
                if (empty($cp_base_url)) {
                    $error_response = [
                        'error' => esc_html__('Custom provider is not configured. Set Base URL in MxChat → API Keys → Custom Provider.', 'mxchat'),
                        'error_code' => 'missing_custom_provider_base_url'
                    ];
                    if ($testing_data !== null) {
                        $error_response['testing_data'] = $testing_data;
                    }
                    return $error_response;
                }
                if ($streaming) {
                    return $this->mxchat_generate_response_custom_stream(
                        $selected_model,
                        $conversation_history,
                        $relevant_content,
                        $session_id,
                        $testing_data
                    );
                } else {
                    $response = $this->mxchat_generate_response_custom(
                        $selected_model,
                        $conversation_history,
                        $relevant_content
                    );
                }
                break;

            case 'gpt':
            case 'o1':
                if (empty($api_key)) {
                    $error_response = [
                        'error' => esc_html__('OpenAI API key is not configured', 'mxchat'),
                        'error_code' => 'missing_openai_api_key'
                    ];
                    if ($testing_data !== null) {
                        $error_response['testing_data'] = $testing_data;
                    }
                    return $error_response;
                }

                // Check if web search is enabled for this OpenAI model
                $web_search_enabled = isset($this->options['enable_web_search']) && $this->options['enable_web_search'] === 'on';
                // Models that don't support web search
                $unsupported_web_search_models = array('gpt-4.1-nano');
                $model_supports_web_search = !in_array($selected_model, $unsupported_web_search_models);

                if ($web_search_enabled && $model_supports_web_search) {
                    // Use Responses API (required for some models, or when web search is enabled)
                    return $this->mxchat_generate_response_openai_web_search(
                        $selected_model,
                        $api_key,
                        $conversation_history,
                        $relevant_content,
                        $session_id,
                        $testing_data,
                        $streaming
                    );
                } elseif ($streaming) {
                    return $this->mxchat_generate_response_openai_stream(
                        $selected_model,
                        $api_key,
                        $conversation_history,
                        $relevant_content,
                        $session_id,
                        $testing_data
                    );
                } else {
                    $response = $this->mxchat_generate_response_openai(
                        $selected_model,
                        $api_key,
                        $conversation_history,
                        $relevant_content,
                        $session_id
                    );
                }
                break;
                
            default:
                if (empty($api_key)) {
                    $error_response = [
                        'error' => esc_html__('OpenAI API key is not configured', 'mxchat'),
                        'error_code' => 'missing_openai_api_key'
                    ];
                    if ($testing_data !== null) {
                        $error_response['testing_data'] = $testing_data;
                    }
                    return $error_response;
                }

                // Check if web search is enabled (default case also handles OpenAI models)
                $web_search_enabled = isset($this->options['enable_web_search']) && $this->options['enable_web_search'] === 'on';
                $unsupported_web_search_models = array('gpt-4.1-nano');
                $model_supports_web_search = !in_array($selected_model, $unsupported_web_search_models);

                if ($web_search_enabled && $model_supports_web_search) {
                    return $this->mxchat_generate_response_openai_web_search(
                        $selected_model,
                        $api_key,
                        $conversation_history,
                        $relevant_content,
                        $session_id,
                        $testing_data,
                        $streaming
                    );
                } elseif ($streaming) {
                    return $this->mxchat_generate_response_openai_stream(
                        $selected_model,
                        $api_key,
                        $conversation_history,
                        $relevant_content,
                        $session_id,
                        $testing_data
                    );
                } else {
                    $response = $this->mxchat_generate_response_openai(
                        $selected_model,
                        $api_key,
                        $conversation_history,
                        $relevant_content,
                        $session_id
                    );
                }
                break;
        }
        
        if (is_array($response) && isset($response['error'])) {
            if ($testing_data !== null) {
                $response['testing_data'] = $testing_data;
            }
            return $response;
        }
        
        return $response;
        
    } catch (Exception $e) {
        $error_response = [
            'error' => sprintf(esc_html__('An error occurred: %s', 'mxchat'), esc_html($e->getMessage())),
            'error_code' => 'system_exception',
            'exception_details' => $e->getMessage()
        ];
        
        if ($testing_data !== null) {
            $error_response['testing_data'] = $testing_data;
        }
        
        return $error_response;
    }
}
private function mxchat_generate_response_openrouter_stream($selected_model, $openrouter_api_key, $conversation_history, $relevant_content, $session_id, $testing_data = null) {
    try {
        $bot_id = $this->get_current_bot_id($session_id);
        $system_prompt_instructions = $this->get_system_instructions($bot_id, $session_id);
        
        if (!is_array($conversation_history)) {
            $conversation_history = array();
        }

        $formatted_conversation = array();

        $formatted_conversation[] = array(
            'role' => 'system',
            'content' => $system_prompt_instructions . " " . $relevant_content
        );

        foreach ($conversation_history as $message) {
            if (is_array($message) && isset($message['role']) && isset($message['content'])) {
                $role = $message['role'];
                if ($role === 'bot' || $role === 'agent') {
                    $role = 'assistant';
                }
                if (!in_array($role, ['system', 'assistant', 'user'])) {
                    $role = 'user';
                }
                $formatted_conversation[] = array(
                    'role' => $role,
                    'content' => $message['content']
                );
            }
        }

        if (headers_sent() || !function_exists('curl_init')) {
            $regular_response = $this->mxchat_generate_response_openrouter(
                $selected_model,
                $openrouter_api_key,
                $conversation_history,
                $relevant_content,
                $session_id
            );
            
            // Save bot response to transcript
            if (!empty($regular_response) && !empty($session_id)) {
                $this->mxchat_save_chat_message($session_id, 'bot', $regular_response);
            }
            
            $response_data = [
                'text' => $regular_response,
                'html' => '',
                'session_id' => $session_id
            ];
            
            if ($testing_data !== null) {
                $response_data['testing_data'] = $testing_data;
            }
            
            header('Content-Type: application/json');
            echo json_encode($response_data);
            return true;
        }

        $body = json_encode([
            'model' => $selected_model,
            'messages' => $formatted_conversation,
            'temperature' => 1,
            'stream' => true
        ]);

        // V2 retry-on-initial-connect: setup_streaming_headers is now lazy-fired
        // inside WRITEFUNCTION on first byte of a successful upstream.

        $captured_status_code = 0;
        $captured_body_pre_stream = '';
        $full_response = '';
        $stream_started = false;
        $buffer = '';
        $errno = 0;
        $last_curl_error = '';
        $http_code = 0;
        $max_attempts = $this->mxchat_retry_enabled() ? 3 : 1;
        $backoff_ms = array(0, 750, 2000);

        for ($attempt = 0; $attempt < $max_attempts; $attempt++) {
            if ($attempt > 0 && $backoff_ms[$attempt] > 0) {
                usleep($backoff_ms[$attempt] * 1000);
            }

            $captured_status_code = 0;
            $captured_body_pre_stream = '';
            $full_response = '';
            $stream_started = false;
            $buffer = '';

            $ch = curl_init();
            curl_setopt($ch, CURLOPT_URL, 'https://openrouter.ai/api/v1/chat/completions');
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, false);
            curl_setopt($ch, CURLOPT_POST, true);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $body);
            curl_setopt($ch, CURLOPT_HTTPHEADER, array(
                'Content-Type: application/json',
                'Authorization: Bearer ' . $openrouter_api_key,
                'HTTP-Referer: ' . home_url(),
                'X-Title: ' . get_bloginfo('name')
            ));
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
            curl_setopt($ch, CURLOPT_TIMEOUT, 60);

            curl_setopt($ch, CURLOPT_HEADERFUNCTION, function($ch, $header) use (&$captured_status_code) {
                if ($captured_status_code === 0 && preg_match('#^HTTP/\S+\s+(\d+)\b#', $header, $m)) {
                    $captured_status_code = (int) $m[1];
                }
                return strlen($header);
            });

            curl_setopt($ch, CURLOPT_WRITEFUNCTION, function($ch, $data) use (&$full_response, &$stream_started, &$buffer, &$captured_status_code, &$captured_body_pre_stream, $testing_data) {
                if ($captured_status_code !== 0 && $captured_status_code !== 200) {
                    $captured_body_pre_stream .= $data;
                    return strlen($data);
                }

                if (!$this->streaming_headers_sent) {
                    $this->setup_streaming_headers();
                }

                if (!$stream_started && $testing_data !== null) {
                    echo "data: " . json_encode(['testing_data' => $testing_data]) . "\n\n";
                    flush();
                    $stream_started = true;
                }

                $buffer .= $data;
                $lines = explode("\n", $buffer);
                $buffer = array_pop($lines);

                foreach ($lines as $line) {
                    if (trim($line) === '') {
                        continue;
                    }
                    if (strpos($line, 'data: ') !== 0) {
                        continue;
                    }

                    $json_str = substr($line, 6);

                    if (trim($json_str) === '[DONE]') {
                        echo "data: [DONE]\n\n";
                        flush();
                        continue;
                    }

                    $json = json_decode(trim($json_str), true);
                    if ($json && isset($json['choices'][0]['delta']['content'])) {
                        $content = $json['choices'][0]['delta']['content'];
                        $full_response .= $content;

                        echo "data: " . json_encode(['content' => $content]) . "\n\n";
                        flush();
                    }
                }

                return strlen($data);
            });

            $response = curl_exec($ch);
            $errno = curl_errno($ch);
            $last_curl_error = curl_error($ch);
            $http_code = $captured_status_code !== 0 ? $captured_status_code : (int) curl_getinfo($ch, CURLINFO_HTTP_CODE);
            curl_close($ch);

            if (!$errno && $http_code === 200) {
                break;
            }

            $is_transient = $this->mxchat_is_transient_provider_error_raw($http_code, $captured_body_pre_stream, 'openai', $errno);
            $can_retry = !$this->streaming_headers_sent
                      && ($attempt + 1) < $max_attempts
                      && $is_transient;

            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log(sprintf(
                    '[MxChat] openrouter_stream initial-connect failure (attempt=%d/%d, status=%d, errno=%d, transient=%s, %s).',
                    $attempt + 1, $max_attempts, $http_code, $errno,
                    $is_transient ? 'yes' : 'no',
                    $can_retry ? 'Retrying.' : 'Giving up.'
                ));
            }

            if (!$can_retry) {
                break;
            }
        }

        if (!$errno && $http_code === 200) {
            if (!empty($full_response) && !empty($session_id)) {
                $rag_context_for_storage = null;
                $has_rag_data = $this->last_similarity_analysis !== null && !empty($this->last_similarity_analysis['top_matches']);
                $has_action_data = isset($this->last_action_analysis) && !empty($this->last_action_analysis);

                if ($has_rag_data || $has_action_data) {
                    $rag_context_for_storage = [];

                    if ($has_rag_data) {
                        $rag_context_for_storage['top_matches'] = $this->last_similarity_analysis['top_matches'];
                        $rag_context_for_storage['approved_urls'] = $this->current_valid_urls ?? [];
                        $rag_context_for_storage['similarity_threshold'] = $this->last_similarity_analysis['threshold_used'] ?? 0.35;
                        $rag_context_for_storage['knowledge_base_type'] = $this->last_similarity_analysis['knowledge_base_type'] ?? 'WordPress Database';
                        $rag_context_for_storage['total_documents_checked'] = $this->last_similarity_analysis['total_checked'] ?? 0;
                    }

                    if ($has_action_data) {
                        $rag_context_for_storage['action_analysis'] = $this->last_action_analysis;
                    }
                }
                $this->mxchat_save_chat_message($session_id, 'bot', $full_response, null, $rag_context_for_storage);
            }
            return true;
        }

        return $this->mxchat_stream_emit_fallback(
            'openai',
            $this->mxchat_generate_response_openrouter($selected_model, $openrouter_api_key, $conversation_history, $relevant_content, $session_id),
            $session_id,
            $testing_data
        );

    } catch (Exception $e) {
        return $this->mxchat_stream_emit_fallback(
            'openai',
            $this->mxchat_generate_response_openrouter($selected_model, $openrouter_api_key, $conversation_history, $relevant_content, $session_id),
            $session_id,
            $testing_data
        );
    }
}
private function mxchat_generate_response_openai_stream($selected_model, $api_key, $conversation_history, $relevant_content, $session_id, $testing_data = null) {
    try {
        $bot_id = $this->get_current_bot_id($session_id);
        
        // Get system prompt instructions using centralized function
        $system_prompt_instructions = $this->get_system_instructions($bot_id, $session_id);
        
        // Ensure conversation_history is an array
        if (!is_array($conversation_history)) {
            $conversation_history = array();
        }

        // Format conversation history for OpenAI
        $formatted_conversation = array();

        $formatted_conversation[] = array(
            'role' => 'system',
            'content' => $system_prompt_instructions . " " . $relevant_content
        );

        foreach ($conversation_history as $message) {
            if (is_array($message) && isset($message['role']) && isset($message['content'])) {
                $role = $message['role'];
                if ($role === 'bot' || $role === 'agent') {
                    $role = 'assistant';
                }
                if (!in_array($role, ['system', 'assistant', 'user', 'function', 'tool'])) {
                    $role = 'user';
                }
                $formatted_conversation[] = array(
                    'role' => $role,
                    'content' => $message['content']
                );
            }
        }

        // Check if we can actually stream
        if (headers_sent() || !function_exists('curl_init')) {
            // Fallback to regular response with testing data
            $regular_response = $this->mxchat_generate_response_openai(
                $selected_model,
                $api_key,
                $conversation_history,
                $relevant_content,
                $session_id
            );
            
            // Save bot response to transcript
            if (!empty($regular_response) && !empty($session_id)) {
                $this->mxchat_save_chat_message($session_id, 'bot', $regular_response);
            }
            
            $response_data = [
                'text' => $regular_response,
                'html' => '',
                'session_id' => $session_id
            ];
            
            if ($testing_data !== null) {
                $response_data['testing_data'] = $testing_data;
            }
            
            header('Content-Type: application/json');
            echo json_encode($response_data);
            return true;
        }

        // Build request body with optimal settings for fast streaming
        $request_body = [
            'model' => $selected_model,
            'messages' => $formatted_conversation,
            'temperature' => 1,
            'stream' => true
        ];

        // reasoning_effort — sourced from the core model catalog (plan-dcb71c);
        // frozen inline ladder lives in mxchat_reasoning_effort_fallback().
        $effort = $this->mxchat_reasoning_effort_for($selected_model, 'chat');
        if ($effort !== null) {
            $request_body['reasoning_effort'] = $effort;
        }

        $body = json_encode($request_body);

        // V2 retry-on-initial-connect: do NOT call setup_streaming_headers() here.
        // It is now lazy-fired inside the WRITEFUNCTION on the first byte of a
        // SUCCESSFUL upstream response, gated by the captured HTTP status.

        $captured_status_code = 0;
        $captured_body_pre_stream = '';
        $full_response = '';
        $stream_started = false;
        $buffer = '';
        $errno = 0;
        $last_curl_error = '';
        $http_code = 0;
        $max_attempts = $this->mxchat_retry_enabled() ? 3 : 1;
        $backoff_ms = array(0, 750, 2000);

        for ($attempt = 0; $attempt < $max_attempts; $attempt++) {
            if ($attempt > 0 && $backoff_ms[$attempt] > 0) {
                usleep($backoff_ms[$attempt] * 1000);
            }

            // Reset per-attempt capture state.
            $captured_status_code = 0;
            $captured_body_pre_stream = '';
            $full_response = '';
            $stream_started = false;
            $buffer = '';

            $ch = curl_init();
            curl_setopt($ch, CURLOPT_URL, 'https://api.openai.com/v1/chat/completions');
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, false);
            curl_setopt($ch, CURLOPT_POST, true);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $body);
            curl_setopt($ch, CURLOPT_HTTPHEADER, array(
                'Content-Type: application/json',
                'Authorization: Bearer ' . $api_key
            ));
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
            curl_setopt($ch, CURLOPT_TIMEOUT, 60);

            // Capture HTTP status as soon as response headers arrive — fires before WRITEFUNCTION.
            curl_setopt($ch, CURLOPT_HEADERFUNCTION, function($ch, $header) use (&$captured_status_code) {
                if ($captured_status_code === 0 && preg_match('#^HTTP/\S+\s+(\d+)\b#', $header, $m)) {
                    $captured_status_code = (int) $m[1];
                }
                return strlen($header);
            });

            // Buffer control for real-time streaming
            curl_setopt($ch, CURLOPT_WRITEFUNCTION, function($ch, $data) use (&$full_response, &$stream_started, &$buffer, &$captured_status_code, &$captured_body_pre_stream, $testing_data) {
                // V2 guard: if upstream returned non-200, buffer body for transient
                // classification and DO NOT emit to client. Stream channel must NOT open.
                if ($captured_status_code !== 0 && $captured_status_code !== 200) {
                    $captured_body_pre_stream .= $data;
                    return strlen($data);
                }

                // Lazy-fire streaming headers on first byte of a SUCCESSFUL upstream.
                // After this point streaming_headers_sent === true → retry is structurally blocked.
                if (!$this->streaming_headers_sent) {
                    $this->setup_streaming_headers();
                }

                // Send testing data as the first event if available
                if (!$stream_started && $testing_data !== null) {
                    echo "data: " . json_encode(['testing_data' => $testing_data]) . "\n\n";
                    flush();
                    $stream_started = true;
                }

                // CRITICAL FIX: Append new data to buffer
                $buffer .= $data;

                // Process complete lines only
                $lines = explode("\n", $buffer);

                // CRITICAL FIX: Keep the last incomplete line in the buffer
                $buffer = array_pop($lines);

                foreach ($lines as $line) {
                    if (trim($line) === '') {
                        continue;
                    }
                    if (strpos($line, 'data: ') !== 0) {
                        continue;
                    }

                    $json_str = substr($line, 6);

                    if (trim($json_str) === '[DONE]') {
                        echo "data: [DONE]\n\n";
                        flush();
                        continue;
                    }

                    $json = json_decode(trim($json_str), true);
                    if ($json && isset($json['choices'][0]['delta']['content'])) {
                        $content = $json['choices'][0]['delta']['content'];
                        $full_response .= $content;

                        echo "data: " . json_encode(['content' => $content]) . "\n\n";
                        flush();
                    }
                }

                return strlen($data);
            });

            $response = curl_exec($ch);
            $errno = curl_errno($ch);
            $last_curl_error = curl_error($ch);
            $http_code = $captured_status_code !== 0 ? $captured_status_code : (int) curl_getinfo($ch, CURLINFO_HTTP_CODE);
            curl_close($ch);

            if (!$errno && $http_code === 200) {
                break; // Happy path — WRITEFUNCTION already streamed everything.
            }

            $is_transient = $this->mxchat_is_transient_provider_error_raw($http_code, $captured_body_pre_stream, 'openai', $errno);
            $can_retry = !$this->streaming_headers_sent
                      && ($attempt + 1) < $max_attempts
                      && $is_transient;

            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log(sprintf(
                    '[MxChat] openai_stream initial-connect failure (attempt=%d/%d, status=%d, errno=%d, transient=%s, %s).',
                    $attempt + 1, $max_attempts, $http_code, $errno,
                    $is_transient ? 'yes' : 'no',
                    $can_retry ? 'Retrying.' : 'Giving up.'
                ));
            }

            if (!$can_retry) {
                break;
            }
        }

        // Post-loop branch.
        if (!$errno && $http_code === 200) {
            // Happy path — save the complete response to maintain chat persistence.
            if (!empty($full_response) && !empty($session_id)) {
                $rag_context_for_storage = null;
                $has_rag_data = $this->last_similarity_analysis !== null && !empty($this->last_similarity_analysis['top_matches']);
                $has_action_data = isset($this->last_action_analysis) && !empty($this->last_action_analysis);

                if ($has_rag_data || $has_action_data) {
                    $rag_context_for_storage = [];

                    if ($has_rag_data) {
                        $rag_context_for_storage['top_matches'] = $this->last_similarity_analysis['top_matches'];
                        $rag_context_for_storage['approved_urls'] = $this->current_valid_urls ?? [];
                        $rag_context_for_storage['similarity_threshold'] = $this->last_similarity_analysis['threshold_used'] ?? 0.35;
                        $rag_context_for_storage['knowledge_base_type'] = $this->last_similarity_analysis['knowledge_base_type'] ?? 'WordPress Database';
                        $rag_context_for_storage['total_documents_checked'] = $this->last_similarity_analysis['total_checked'] ?? 0;
                    }

                    if ($has_action_data) {
                        $rag_context_for_storage['action_analysis'] = $this->last_action_analysis;
                    }
                }
                $this->mxchat_save_chat_message($session_id, 'bot', $full_response, null, $rag_context_for_storage);
            }

            return true;
        }

        // Failure path — branch on whether SSE channel was opened.
        return $this->mxchat_stream_emit_fallback(
            'openai',
            $this->mxchat_generate_response_openai($selected_model, $api_key, $conversation_history, $relevant_content, $session_id),
            $session_id,
            $testing_data
        );

    } catch (Exception $e) {
        return $this->mxchat_stream_emit_fallback(
            'openai',
            $this->mxchat_generate_response_openai($selected_model, $api_key, $conversation_history, $relevant_content, $session_id),
            $session_id,
            $testing_data
        );
    }
}

/**
 * Shared fallback emitter for streaming chat functions. Two outcomes:
 *  - streaming_headers_sent === true: SSE channel is open. Emit fallback content
 *    as `data: {...}\n\n` + `data: [DONE]\n\n` so the widget renders it as a
 *    normal bot bubble. Transcript row is persisted.
 *  - streaming_headers_sent === false: SSE channel never opened (retries
 *    exhausted on initial connect). Emit a clean JSON response — the path
 *    the widget would normally hit if streaming wasn't even attempted.
 *
 * Used by all six *_stream functions after their per-attempt retry loop.
 */
private function mxchat_stream_emit_fallback($provider_hint, $regular_response, $session_id, $testing_data = null) {
    $is_error_array = is_array($regular_response) && isset($regular_response['error']);

    if ($this->streaming_headers_sent) {
        if ($is_error_array) {
            echo "data: " . json_encode([
                'error' => true,
                'error_message' => $regular_response['error'],
                'error_code' => $regular_response['error_code'] ?? 'api_error',
                'text' => $regular_response['error'],
                'message' => $regular_response['error']
            ]) . "\n\n";
            echo "data: [DONE]\n\n";
            flush();
            return true;
        }
        $fallback_message = (string) $regular_response;
        if (!empty($fallback_message) && !empty($session_id)) {
            $this->mxchat_save_chat_message($session_id, 'bot', $fallback_message);
        }
        echo "data: " . json_encode(['content' => $fallback_message]) . "\n\n";
        echo "data: [DONE]\n\n";
        flush();
        return true;
    }

    // SSE channel never opened — clean JSON fallback.
    if ($is_error_array) {
        header('Content-Type: application/json');
        echo json_encode(array(
            'error' => true,
            'error_message' => $regular_response['error'],
            'error_code' => $regular_response['error_code'] ?? 'api_error',
            'text' => $regular_response['error'],
            'message' => $regular_response['error'],
        ));
        return true;
    }

    $fallback_message = (string) $regular_response;
    if (!empty($fallback_message) && !empty($session_id)) {
        $this->mxchat_save_chat_message($session_id, 'bot', $fallback_message);
    }
    $response_data = array(
        'text' => $fallback_message,
        'html' => '',
        'session_id' => $session_id,
    );
    if ($testing_data !== null) {
        $response_data['testing_data'] = $testing_data;
    }
    header('Content-Type: application/json');
    echo json_encode($response_data);
    return true;
}

/**
 * Resolve custom (OpenAI-compatible) provider config from settings.
 * Returns ['base_url','api_key','model','auth_scheme','api_version','chat_url','headers'].
 */
private function mxchat_resolve_custom_provider() {
    $base_url    = isset($this->options['custom_provider_base_url']) ? rtrim(trim((string) $this->options['custom_provider_base_url']), '/') : '';
    $api_key     = isset($this->options['custom_provider_api_key']) ? trim((string) $this->options['custom_provider_api_key']) : '';
    $model       = isset($this->options['custom_provider_model']) ? trim((string) $this->options['custom_provider_model']) : '';
    $auth_scheme = isset($this->options['custom_provider_auth_scheme']) ? $this->options['custom_provider_auth_scheme'] : 'bearer';
    $api_version = isset($this->options['custom_provider_api_version']) ? trim((string) $this->options['custom_provider_api_version']) : '';

    $chat_url = $base_url . '/chat/completions';
    if (!empty($api_version)) {
        $chat_url .= (strpos($chat_url, '?') === false ? '?' : '&') . 'api-version=' . rawurlencode($api_version);
    }

    $headers = array('Content-Type: application/json');
    if (!empty($api_key)) {
        if ($auth_scheme === 'api-key') {
            $headers[] = 'api-key: ' . $api_key;
        } else {
            $headers[] = 'Authorization: Bearer ' . $api_key;
        }
    }

    return array(
        'base_url'    => $base_url,
        'api_key'     => $api_key,
        'model'       => $model !== '' ? $model : 'default',
        'auth_scheme' => $auth_scheme,
        'api_version' => $api_version,
        'chat_url'    => $chat_url,
        'headers'     => $headers,
    );
}

/**
 * Streaming chat completion against an OpenAI-compatible custom provider
 * (Ollama, LM Studio, vLLM, llama.cpp, Azure OpenAI, etc.).
 * Mirrors mxchat_generate_response_openai_stream but with parameterized URL/auth/model.
 */
private function mxchat_generate_response_custom_stream($selected_model, $conversation_history, $relevant_content, $session_id, $testing_data = null) {
    try {
        $cfg = $this->mxchat_resolve_custom_provider();
        if (empty($cfg['base_url'])) {
            return array('error' => esc_html__('Custom provider Base URL is not configured.', 'mxchat'), 'error_code' => 'missing_custom_provider_base_url');
        }

        $bot_id = $this->get_current_bot_id($session_id);
        $system_prompt_instructions = $this->get_system_instructions($bot_id, $session_id);
        if (!is_array($conversation_history)) {
            $conversation_history = array();
        }

        $formatted_conversation = array();
        $formatted_conversation[] = array(
            'role' => 'system',
            'content' => $system_prompt_instructions . ' ' . $relevant_content,
        );
        foreach ($conversation_history as $message) {
            if (is_array($message) && isset($message['role']) && isset($message['content'])) {
                $role = $message['role'];
                if ($role === 'bot' || $role === 'agent') { $role = 'assistant'; }
                if (!in_array($role, array('system', 'assistant', 'user', 'function', 'tool'))) { $role = 'user'; }
                $formatted_conversation[] = array('role' => $role, 'content' => $message['content']);
            }
        }

        if (headers_sent() || !function_exists('curl_init')) {
            // No streaming capability — fall through to non-stream wrapper
            $regular = $this->mxchat_generate_response_custom($selected_model, $conversation_history, $relevant_content);
            if (!empty($regular) && !empty($session_id) && is_string($regular)) {
                $this->mxchat_save_chat_message($session_id, 'bot', $regular);
            }
            $response_data = array('text' => is_string($regular) ? $regular : '', 'html' => '', 'session_id' => $session_id);
            if ($testing_data !== null) { $response_data['testing_data'] = $testing_data; }
            header('Content-Type: application/json');
            echo json_encode($response_data);
            return true;
        }

        $request_body = array(
            'model'    => $cfg['model'],
            'messages' => $formatted_conversation,
            'stream'   => true,
        );
        $body = json_encode($request_body);

        // V2 retry-on-initial-connect: setup_streaming_headers is lazy-fired in WRITEFUNCTION.

        $captured_status_code = 0;
        $captured_body_pre_stream = '';
        $full_response = '';
        $stream_started = false;
        $buffer = '';
        $errno = 0;
        $http_code = 0;
        $max_attempts = $this->mxchat_retry_enabled() ? 3 : 1;
        $backoff_ms = array(0, 750, 2000);

        for ($attempt = 0; $attempt < $max_attempts; $attempt++) {
            if ($attempt > 0 && $backoff_ms[$attempt] > 0) {
                usleep($backoff_ms[$attempt] * 1000);
            }

            $captured_status_code = 0;
            $captured_body_pre_stream = '';
            $full_response = '';
            $stream_started = false;
            $buffer = '';

            $ch = curl_init();
            curl_setopt($ch, CURLOPT_URL, $cfg['chat_url']);
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, false);
            curl_setopt($ch, CURLOPT_POST, true);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $body);
            curl_setopt($ch, CURLOPT_HTTPHEADER, $cfg['headers']);
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
            curl_setopt($ch, CURLOPT_TIMEOUT, 120);

            curl_setopt($ch, CURLOPT_HEADERFUNCTION, function($ch, $header) use (&$captured_status_code) {
                if ($captured_status_code === 0 && preg_match('#^HTTP/\S+\s+(\d+)\b#', $header, $m)) {
                    $captured_status_code = (int) $m[1];
                }
                return strlen($header);
            });

            curl_setopt($ch, CURLOPT_WRITEFUNCTION, function($ch, $data) use (&$full_response, &$stream_started, &$buffer, &$captured_status_code, &$captured_body_pre_stream, $testing_data) {
                if ($captured_status_code !== 0 && $captured_status_code !== 200) {
                    $captured_body_pre_stream .= $data;
                    return strlen($data);
                }

                if (!$this->streaming_headers_sent) {
                    $this->setup_streaming_headers();
                }

                if (!$stream_started && $testing_data !== null) {
                    echo "data: " . json_encode(array('testing_data' => $testing_data)) . "\n\n";
                    flush();
                    $stream_started = true;
                }
                $buffer .= $data;
                $lines = explode("\n", $buffer);
                $buffer = array_pop($lines);
                foreach ($lines as $line) {
                    if (trim($line) === '') { continue; }
                    if (strpos($line, 'data: ') !== 0) { continue; }
                    $json_str = substr($line, 6);
                    if (trim($json_str) === '[DONE]') {
                        echo "data: [DONE]\n\n";
                        flush();
                        continue;
                    }
                    $json = json_decode(trim($json_str), true);
                    if ($json && isset($json['choices'][0]['delta']['content'])) {
                        $content = $json['choices'][0]['delta']['content'];
                        $full_response .= $content;
                        echo "data: " . json_encode(array('content' => $content)) . "\n\n";
                        flush();
                    }
                }
                return strlen($data);
            });

            $response = curl_exec($ch);
            $errno = curl_errno($ch);
            $http_code = $captured_status_code !== 0 ? $captured_status_code : (int) curl_getinfo($ch, CURLINFO_HTTP_CODE);
            curl_close($ch);

            if (!$errno && $http_code === 200) {
                break;
            }

            $is_transient = $this->mxchat_is_transient_provider_error_raw($http_code, $captured_body_pre_stream, 'openai', $errno);
            $can_retry = !$this->streaming_headers_sent
                      && ($attempt + 1) < $max_attempts
                      && $is_transient;

            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log(sprintf(
                    '[MxChat] custom_stream initial-connect failure (attempt=%d/%d, status=%d, errno=%d, transient=%s, %s).',
                    $attempt + 1, $max_attempts, $http_code, $errno,
                    $is_transient ? 'yes' : 'no',
                    $can_retry ? 'Retrying.' : 'Giving up.'
                ));
            }

            if (!$can_retry) {
                break;
            }
        }

        if (!$errno && $http_code === 200) {
            if (!empty($full_response) && !empty($session_id)) {
                $this->mxchat_save_chat_message($session_id, 'bot', $full_response);
            }
            return true;
        }

        return $this->mxchat_stream_emit_fallback(
            'openai',
            $this->mxchat_generate_response_custom($selected_model, $conversation_history, $relevant_content),
            $session_id,
            $testing_data
        );

    } catch (Exception $e) {
        return array('error' => sprintf(esc_html__('Custom provider error: %s', 'mxchat'), $e->getMessage()), 'error_code' => 'custom_provider_exception');
    }
}

/**
 * Non-streaming chat completion against a custom OpenAI-compatible provider.
 * Returns string content on success, array['error'=>...] on failure.
 */
private function mxchat_generate_response_custom($selected_model, $conversation_history, $relevant_content) {
    $cfg = $this->mxchat_resolve_custom_provider();
    if (empty($cfg['base_url'])) {
        return array('error' => esc_html__('Custom provider Base URL is not configured.', 'mxchat'), 'error_code' => 'missing_custom_provider_base_url');
    }

    $bot_id = $this->get_current_bot_id(null);
    $system_prompt_instructions = $this->get_system_instructions($bot_id, null);
    if (!is_array($conversation_history)) {
        $conversation_history = array();
    }

    $messages = array(array(
        'role' => 'system',
        'content' => $system_prompt_instructions . ' ' . $relevant_content,
    ));
    foreach ($conversation_history as $message) {
        if (is_array($message) && isset($message['role']) && isset($message['content'])) {
            $role = $message['role'];
            if ($role === 'bot' || $role === 'agent') { $role = 'assistant'; }
            if (!in_array($role, array('system', 'assistant', 'user', 'function', 'tool'))) { $role = 'user'; }
            $messages[] = array('role' => $role, 'content' => $message['content']);
        }
    }

    $headers_assoc = array('Content-Type' => 'application/json');
    if (!empty($cfg['api_key'])) {
        if ($cfg['auth_scheme'] === 'api-key') {
            $headers_assoc['api-key'] = $cfg['api_key'];
        } else {
            $headers_assoc['Authorization'] = 'Bearer ' . $cfg['api_key'];
        }
    }

    $response = $this->mxchat_provider_call_with_retry($cfg['chat_url'], array(
        'headers' => $headers_assoc,
        'body'    => wp_json_encode(array(
            'model'    => $cfg['model'],
            'messages' => $messages,
        )),
        'timeout' => 120,
    ), 'openai');

    if (is_wp_error($response)) {
        return array('error' => sprintf(esc_html__('Custom provider request failed: %s', 'mxchat'), $response->get_error_message()), 'error_code' => 'custom_provider_network_error');
    }
    $code = (int) wp_remote_retrieve_response_code($response);
    if ($code < 200 || $code >= 300) {
        return array('error' => sprintf(esc_html__('Custom provider returned HTTP %d.', 'mxchat'), $code), 'error_code' => 'custom_provider_http_error');
    }
    $body = json_decode(wp_remote_retrieve_body($response), true);
    if (isset($body['choices'][0]['message']['content'])) {
        return (string) $body['choices'][0]['message']['content'];
    }
    return array('error' => esc_html__('Custom provider returned an unexpected response shape.', 'mxchat'), 'error_code' => 'custom_provider_response_shape');
}

/**
 * Generate response using OpenAI Responses API with web search tool
 * This uses the newer Responses API which supports web search functionality
 */
private function mxchat_generate_response_openai_web_search($selected_model, $api_key, $conversation_history, $relevant_content, $session_id, $testing_data = null, $streaming = false) {
    try {
        $bot_id = $this->get_current_bot_id($session_id);
        $system_prompt_instructions = $this->get_system_instructions($bot_id, $session_id);

        if (!is_array($conversation_history)) {
            $conversation_history = array();
        }

        // Build the input for Responses API
        // The Responses API uses a different format - we need to construct the input properly
        $input_parts = [];

        // Add system instructions as context
        $system_context = $system_prompt_instructions . "\n\n" . $relevant_content;

        // Build conversation as input items for Responses API
        foreach ($conversation_history as $message) {
            if (is_array($message) && isset($message['role']) && isset($message['content'])) {
                $role = $message['role'];
                if ($role === 'bot' || $role === 'agent') {
                    $role = 'assistant';
                }
                if (!in_array($role, ['assistant', 'user'])) {
                    $role = 'user';
                }
                $input_parts[] = [
                    'type' => 'message',
                    'role' => $role,
                    'content' => $message['content']
                ];
            }
        }

        // Build request body for Responses API
        $request_body = [
            'model' => $selected_model,
            'input' => $input_parts,
            'instructions' => $system_context,
            'stream' => $streaming
        ];

        // Only add web search tool if web search is enabled in settings
        $web_search_enabled = isset($this->options['enable_web_search']) && $this->options['enable_web_search'] === 'on';
        if ($web_search_enabled) {
            $request_body['tools'] = [
                ['type' => 'web_search']
            ];
        }

        // reasoning.effort — sourced from the core model catalog (plan-dcb71c),
        // 'websearch' surface; frozen inline ladder in mxchat_reasoning_effort_fallback().
        $effort = $this->mxchat_reasoning_effort_for($selected_model, 'websearch');
        if ($effort !== null) {
            $request_body['reasoning'] = ['effort' => $effort];
        }

        //error_log("MXCHAT WEB SEARCH: Request body: " . json_encode($request_body));

        if ($streaming) {
            return $this->mxchat_web_search_streaming_response($request_body, $api_key, $session_id, $testing_data);
        } else {
            return $this->mxchat_web_search_non_streaming_response($request_body, $api_key, $session_id, $testing_data);
        }

    } catch (Exception $e) {
        //error_log("MXCHAT WEB SEARCH ERROR: " . $e->getMessage());
        return [
            'error' => sprintf(esc_html__('Web search error: %s', 'mxchat'), esc_html($e->getMessage())),
            'error_code' => 'web_search_exception'
        ];
    }
}

/**
 * Handle non-streaming web search response
 */
private function mxchat_web_search_non_streaming_response($request_body, $api_key, $session_id, $testing_data) {
    $request_body['stream'] = false;

    $response = $this->mxchat_provider_call_with_retry('https://api.openai.com/v1/responses', array(
        'headers' => array(
            'Authorization' => 'Bearer ' . $api_key,
            'Content-Type' => 'application/json'
        ),
        'body' => json_encode($request_body),
        'timeout' => 90
    ), 'openai');

    if (is_wp_error($response)) {
        //error_log("MXCHAT WEB SEARCH ERROR: WP Error: " . $response->get_error_message());
        return [
            'error' => esc_html__('Failed to connect to OpenAI web search API', 'mxchat'),
            'error_code' => 'web_search_connection_error'
        ];
    }

    $response_code = wp_remote_retrieve_response_code($response);
    $response_body = wp_remote_retrieve_body($response);

    //error_log("MXCHAT WEB SEARCH: Response code: " . $response_code);
    //error_log("MXCHAT WEB SEARCH: Response body (first 2000): " . substr($response_body, 0, 2000));

    if ($response_code !== 200) {
        $error_data = json_decode($response_body, true);
        $error_message = $this->extract_provider_error($error_data, 'Unknown API error');
        return [
            'error' => sprintf(esc_html__('OpenAI API error: %s', 'mxchat'), esc_html($error_message)),
            'error_code' => 'web_search_api_error'
        ];
    }

    $result = json_decode($response_body, true);

    if (json_last_error() !== JSON_ERROR_NONE) {
        return [
            'error' => esc_html__('Invalid response from OpenAI', 'mxchat'),
            'error_code' => 'web_search_json_error'
        ];
    }

    // Extract the response text and citations from Responses API format
    $output_text = '';
    $citations = [];

    if (isset($result['output'])) {
        foreach ($result['output'] as $output_item) {
            if ($output_item['type'] === 'message' && isset($output_item['content'])) {
                foreach ($output_item['content'] as $content_item) {
                    if ($content_item['type'] === 'output_text') {
                        $output_text .= $content_item['text'];

                        // Extract citations/annotations
                        if (isset($content_item['annotations'])) {
                            foreach ($content_item['annotations'] as $annotation) {
                                if ($annotation['type'] === 'url_citation') {
                                    $citations[] = [
                                        'url' => $annotation['url'],
                                        'title' => $annotation['title'] ?? ''
                                    ];
                                }
                            }
                        }
                    }
                }
            }
        }
    }

    // If we have citations, append them to the response
    if (!empty($citations)) {
        $output_text .= "\n\n**Sources:**\n";
        $seen_urls = [];
        foreach ($citations as $citation) {
            if (!in_array($citation['url'], $seen_urls)) {
                $seen_urls[] = $citation['url'];
                $title = !empty($citation['title']) ? $citation['title'] : $citation['url'];
                $output_text .= "- [" . $title . "](" . $citation['url'] . ")\n";
            }
        }
    }

    // Transcript save is handled by the main handler (mxchat_handle_chat_request)
    // which includes rag_context for the "sources" link in transcripts.

    // plan-4aa8e5: a 200 whose output carries no output_text (status
    // "incomplete" with max_output_tokens exhausted, content-filter-emptied
    // output, shape drift) previously fell through and returned '' — a
    // silent empty bot bubble. This is the DEFAULT model path
    // (gpt-5.1-chat-latest routes through /v1/responses).
    if (trim($output_text) === '') {
        return $this->mxchat_empty_completion_error($result, 'OpenAI');
    }

    return $output_text;
}

/**
 * Handle streaming web search response using Responses API
 */
private function mxchat_web_search_streaming_response($request_body, $api_key, $session_id, $testing_data) {
    $request_body['stream'] = true;

    // Check if we can stream
    if (headers_sent() || !function_exists('curl_init')) {
        // Fallback to non-streaming
        return $this->mxchat_web_search_non_streaming_response($request_body, $api_key, $session_id, $testing_data);
    }

    // Setup streaming headers
    $this->setup_streaming_headers();

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, 'https://api.openai.com/v1/responses');
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, false);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($request_body));
    curl_setopt($ch, CURLOPT_HTTPHEADER, array(
        'Content-Type: application/json',
        'Authorization: Bearer ' . $api_key
    ));
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
    curl_setopt($ch, CURLOPT_TIMEOUT, 120);

    $full_response = '';
    $stream_started = false;
    $buffer = '';
    $citations = [];
    $empty_error_emitted = false;

    curl_setopt($ch, CURLOPT_WRITEFUNCTION, function($ch, $data) use (&$full_response, &$stream_started, &$buffer, &$citations, &$empty_error_emitted, $testing_data) {
        // Send testing data as first event if available
        if (!$stream_started && $testing_data !== null) {
            echo "data: " . json_encode(['testing_data' => $testing_data]) . "\n\n";
            flush();
            $stream_started = true;
        }

        $buffer .= $data;
        $lines = explode("\n", $buffer);
        $buffer = array_pop($lines);

        foreach ($lines as $line) {
            if (trim($line) === '') continue;
            if (strpos($line, 'data: ') !== 0) continue;

            $json_str = substr($line, 6);

            if (trim($json_str) === '[DONE]') {
                // Append citations if we have any
                if (!empty($citations)) {
                    $citation_text = "\n\n**Sources:**\n";
                    $seen_urls = [];
                    foreach ($citations as $citation) {
                        if (!in_array($citation['url'], $seen_urls)) {
                            $seen_urls[] = $citation['url'];
                            $title = !empty($citation['title']) ? $citation['title'] : $citation['url'];
                            $citation_text .= "- [" . $title . "](" . $citation['url'] . ")\n";
                        }
                    }
                    echo "data: " . json_encode(['content' => $citation_text]) . "\n\n";
                    $full_response .= $citation_text;
                    flush();
                }
                // plan-4aa8e5: zero deltas streamed → say so instead of
                // closing a silent empty bubble (client renders text events).
                if (trim($full_response) === '' && !$empty_error_emitted) {
                    $empty_error_emitted = true;
                    echo "data: " . json_encode(['content' => esc_html__('The AI provider returned an empty response. Please try again.', 'mxchat')]) . "\n\n";
                }
                echo "data: [DONE]\n\n";
                flush();
                continue;
            }

            $json = json_decode(trim($json_str), true);
            if (!$json) continue;

            // Handle Responses API streaming events
            // The format is different from Chat Completions
            if (isset($json['type'])) {
                switch ($json['type']) {
                    case 'response.output_text.delta':
                        // Text content delta
                        if (isset($json['delta'])) {
                            $content = $json['delta'];
                            $full_response .= $content;
                            echo "data: " . json_encode(['content' => $content]) . "\n\n";
                            flush();
                        }
                        break;

                    case 'response.output_item.done':
                        // Check for citations in completed items
                        if (isset($json['item']['content'])) {
                            foreach ($json['item']['content'] as $content_item) {
                                if (isset($content_item['annotations'])) {
                                    foreach ($content_item['annotations'] as $annotation) {
                                        if ($annotation['type'] === 'url_citation') {
                                            $citations[] = [
                                                'url' => $annotation['url'],
                                                'title' => $annotation['title'] ?? ''
                                            ];
                                        }
                                    }
                                }
                            }
                        }
                        break;
                }
            }
        }

        return strlen($data);
    });

    $response = curl_exec($ch);
    $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);

    if (curl_errno($ch) || $http_code !== 200) {
        $curl_error = curl_error($ch);
        curl_close($ch);

        //error_log("MXCHAT WEB SEARCH STREAM ERROR: HTTP $http_code, cURL error: $curl_error");

        return $this->mxchat_stream_emit_fallback(
            'web_search',
            $this->mxchat_web_search_non_streaming_response($request_body, $api_key, $session_id, $testing_data),
            $session_id,
            $testing_data
        );
    }

    curl_close($ch);

    // plan-4aa8e5: the Responses API can end its stream via typed events
    // without a [DONE] line — if nothing was streamed at all, close out with
    // the empty-completion message instead of leaving a silent bubble.
    if (trim($full_response) === '' && !$empty_error_emitted) {
        echo "data: " . json_encode(['content' => esc_html__('The AI provider returned an empty response. Please try again.', 'mxchat')]) . "\n\n";
        echo "data: [DONE]\n\n";
        flush();
    }

    // Save the complete response with RAG context so the "sources" link
    // appears in transcripts — mirrors the pattern used by Claude/OpenAI streaming.
    if (!empty($full_response) && !empty($session_id)) {
        $rag_context_for_storage = null;
        $has_rag_data = $this->last_similarity_analysis !== null && !empty($this->last_similarity_analysis['top_matches']);
        $has_action_data = isset($this->last_action_analysis) && !empty($this->last_action_analysis);

        if ($has_rag_data || $has_action_data) {
            $rag_context_for_storage = [];

            if ($has_rag_data) {
                $rag_context_for_storage['top_matches'] = $this->last_similarity_analysis['top_matches'];
                $rag_context_for_storage['approved_urls'] = $this->current_valid_urls ?? [];
                $rag_context_for_storage['similarity_threshold'] = $this->last_similarity_analysis['threshold_used'] ?? 0.35;
                $rag_context_for_storage['knowledge_base_type'] = $this->last_similarity_analysis['knowledge_base_type'] ?? 'WordPress Database';
                $rag_context_for_storage['total_documents_checked'] = $this->last_similarity_analysis['total_checked'] ?? 0;
            }

            if ($has_action_data) {
                $rag_context_for_storage['action_analysis'] = $this->last_action_analysis;
            }
        }
        $this->mxchat_save_chat_message($session_id, 'bot', $full_response, null, $rag_context_for_storage);
    }

    return true;
}

private function mxchat_generate_response_claude_stream($selected_model, $claude_api_key, $conversation_history, $relevant_content, $session_id, $testing_data = null) {
    // Anthropic retired claude-opus-4-20250514 / claude-sonnet-4-20250514 on 2026-06-15.
    // Read-time rescue: remap a saved dead ID to the current equivalent before the API call.
    if ($selected_model === 'claude-opus-4-20250514') { $selected_model = 'claude-opus-4-8'; }
    elseif ($selected_model === 'claude-sonnet-4-20250514') { $selected_model = 'claude-sonnet-4-6'; }
    try {
        // Get bot ID from session or request
        $bot_id = $this->get_current_bot_id($session_id);
        
        // Get system prompt instructions using centralized function
        $system_prompt_instructions = $this->get_system_instructions($bot_id, $session_id);
        // Ensure conversation_history is an array
        if (!is_array($conversation_history)) {
            $conversation_history = array();
        }

        // Clean and validate conversation history
        foreach ($conversation_history as &$message) {
            // Convert bot and agent roles to assistant
            if ($message['role'] === 'bot' || $message['role'] === 'agent') {
                $message['role'] = 'assistant';
            }
            
            // Remove unsupported roles - Claude only supports 'assistant' and 'user'
            if (!in_array($message['role'], ['assistant', 'user'])) {
                $message['role'] = 'user';
            }

            // Ensure content field exists
            if (!isset($message['content']) || empty($message['content'])) {
                $message['content'] = '';
            }

            // Remove any unsupported fields
            $message = array_intersect_key($message, array_flip(['role', 'content']));
        }

        // Add relevant content as the latest user message
        $conversation_history[] = [
            'role' => 'user',
            'content' => $relevant_content
        ];

        // Prepare the request body with stream: true
        $payload = [
            'model' => $selected_model,
            'messages' => $conversation_history,
            'max_tokens' => 1000,
            'temperature' => 0.8,
            'system' => $system_prompt_instructions,
            'stream' => true
        ];
        if ($this->mxchat_claude_omits_temperature($selected_model)) { unset($payload['temperature']); }
        $body = json_encode($payload);

        // Check if we can actually stream (headers not sent, etc.)
        if (headers_sent() || !function_exists('curl_init')) {
            // Fallback to regular response with testing data
            //error_log("MxChat: Streaming not possible, falling back to regular response");
            $regular_response = $this->mxchat_generate_response_claude(
                $selected_model,
                $claude_api_key,
                array_slice($conversation_history, 0, -1), // Remove the added content
                $relevant_content,
                $session_id
            );
            
            // Save bot response to transcript
            if (!empty($regular_response) && !empty($session_id)) {
                $this->mxchat_save_chat_message($session_id, 'bot', $regular_response);
            }
            
            // Return as JSON with testing data
            $response_data = [
                'text' => $regular_response,
                'html' => '',
                'session_id' => $session_id
            ];
            
            if ($testing_data !== null) {
                $response_data['testing_data'] = $testing_data;
                //error_log("MxChat Testing: Added testing data to Claude fallback response");
            }
            
            // Clear any streaming headers and send JSON
            if (headers_sent() === false) {
                header('Content-Type: application/json');
            }
            echo json_encode($response_data);
            return true; // Indicate we handled the response
        }

        // V2 retry-on-initial-connect: setup_streaming_headers is lazy-fired in WRITEFUNCTION.

        $captured_status_code = 0;
        $captured_body_pre_stream = '';
        $full_response = '';
        $stream_started = false;
        $buffer = '';
        $errno = 0;
        $http_code = 0;
        $max_attempts = $this->mxchat_retry_enabled() ? 3 : 1;
        $backoff_ms = array(0, 750, 2000);

        for ($attempt = 0; $attempt < $max_attempts; $attempt++) {
            if ($attempt > 0 && $backoff_ms[$attempt] > 0) {
                usleep($backoff_ms[$attempt] * 1000);
            }

            $captured_status_code = 0;
            $captured_body_pre_stream = '';
            $full_response = '';
            $stream_started = false;
            $buffer = '';

            $ch = curl_init();
            curl_setopt($ch, CURLOPT_URL, 'https://api.anthropic.com/v1/messages');
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, false);
            curl_setopt($ch, CURLOPT_POST, true);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $body);
            curl_setopt($ch, CURLOPT_HTTPHEADER, array(
                'Content-Type: application/json',
                'x-api-key: ' . $claude_api_key,
                'anthropic-version: 2023-06-01'
            ));
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
            curl_setopt($ch, CURLOPT_TIMEOUT, 60);

            curl_setopt($ch, CURLOPT_HEADERFUNCTION, function($ch, $header) use (&$captured_status_code) {
                if ($captured_status_code === 0 && preg_match('#^HTTP/\S+\s+(\d+)\b#', $header, $m)) {
                    $captured_status_code = (int) $m[1];
                }
                return strlen($header);
            });

            curl_setopt($ch, CURLOPT_WRITEFUNCTION, function($ch, $data) use (&$full_response, &$stream_started, &$buffer, &$captured_status_code, &$captured_body_pre_stream, $testing_data) {
                if ($captured_status_code !== 0 && $captured_status_code !== 200) {
                    $captured_body_pre_stream .= $data;
                    return strlen($data);
                }

                if (!$this->streaming_headers_sent) {
                    $this->setup_streaming_headers();
                }

                if (!$stream_started && $testing_data !== null) {
                    echo "data: " . json_encode(['testing_data' => $testing_data]) . "\n\n";
                    flush();
                    $stream_started = true;
                }

                $buffer .= $data;
                $lines = explode("\n", $buffer);
                $buffer = array_pop($lines);

                foreach ($lines as $line) {
                    if (trim($line) === '') {
                        continue;
                    }

                    if (strpos($line, 'event: ') === 0) {
                        continue;
                    }

                    if (strpos($line, 'data: ') === 0) {
                        $json_str = substr($line, 6);

                        $json = json_decode(trim($json_str), true);
                        if (json_last_error() !== JSON_ERROR_NONE) {
                            continue;
                        }

                        if (isset($json['type'])) {
                            switch ($json['type']) {
                                case 'content_block_delta':
                                    if (isset($json['delta']['text'])) {
                                        $content = $json['delta']['text'];
                                        $full_response .= $content;
                                        echo "data: " . json_encode(['content' => $content]) . "\n\n";
                                        flush();
                                    }
                                    break;

                                case 'message_stop':
                                    echo "data: [DONE]\n\n";
                                    flush();
                                    break;

                                case 'error':
                                    echo "data: " . json_encode(['error' => $this->extract_provider_error($json, 'Unknown error')]) . "\n\n";
                                    flush();
                                    break;
                            }
                        }
                    }
                }

                return strlen($data);
            });

            $response = curl_exec($ch);
            $errno = curl_errno($ch);
            $http_code = $captured_status_code !== 0 ? $captured_status_code : (int) curl_getinfo($ch, CURLINFO_HTTP_CODE);
            curl_close($ch);

            if (!$errno && $http_code === 200) {
                break;
            }

            $is_transient = $this->mxchat_is_transient_provider_error_raw($http_code, $captured_body_pre_stream, 'anthropic', $errno);
            $can_retry = !$this->streaming_headers_sent
                      && ($attempt + 1) < $max_attempts
                      && $is_transient;

            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log(sprintf(
                    '[MxChat] claude_stream initial-connect failure (attempt=%d/%d, status=%d, errno=%d, transient=%s, %s).',
                    $attempt + 1, $max_attempts, $http_code, $errno,
                    $is_transient ? 'yes' : 'no',
                    $can_retry ? 'Retrying.' : 'Giving up.'
                ));
            }

            if (!$can_retry) {
                break;
            }
        }

        if ($errno || $http_code !== 200) {
            return $this->mxchat_stream_emit_fallback(
                'anthropic',
                $this->mxchat_generate_response_claude($selected_model, $claude_api_key, array_slice($conversation_history, 0, -1), $relevant_content, $session_id),
                $session_id,
                $testing_data
            );
        }

        // Save the complete response to maintain chat persistence
        if (!empty($full_response) && !empty($session_id)) {
            // Prepare RAG context for streaming response
            $rag_context_for_storage = null;
            $has_rag_data = $this->last_similarity_analysis !== null && !empty($this->last_similarity_analysis['top_matches']);
            $has_action_data = isset($this->last_action_analysis) && !empty($this->last_action_analysis);

            if ($has_rag_data || $has_action_data) {
                $rag_context_for_storage = [];

                if ($has_rag_data) {
                    $rag_context_for_storage['top_matches'] = $this->last_similarity_analysis['top_matches'];
                    $rag_context_for_storage['approved_urls'] = $this->current_valid_urls ?? [];
                    $rag_context_for_storage['similarity_threshold'] = $this->last_similarity_analysis['threshold_used'] ?? 0.35;
                    $rag_context_for_storage['knowledge_base_type'] = $this->last_similarity_analysis['knowledge_base_type'] ?? 'WordPress Database';
                    $rag_context_for_storage['total_documents_checked'] = $this->last_similarity_analysis['total_checked'] ?? 0;
                }

                if ($has_action_data) {
                    $rag_context_for_storage['action_analysis'] = $this->last_action_analysis;
                }
            }
            $this->mxchat_save_chat_message($session_id, 'bot', $full_response, null, $rag_context_for_storage);
        }

        return true; // Indicate streaming completed successfully

    } catch (Exception $e) {
        return $this->mxchat_stream_emit_fallback(
            'anthropic',
            $this->mxchat_generate_response_claude($selected_model, $claude_api_key, $conversation_history, $relevant_content, $session_id),
            $session_id,
            $testing_data
        );
    }
}
private function mxchat_generate_response_xai_stream($selected_model, $xai_api_key, $conversation_history, $relevant_content, $session_id, $testing_data = null) {
    try {
        // Get bot ID from session or request
        $bot_id = $this->get_current_bot_id($session_id);
        
        // Get system prompt instructions using centralized function
        $system_prompt_instructions = $this->get_system_instructions($bot_id, $session_id);
        
        // Ensure conversation_history is an array
        if (!is_array($conversation_history)) {
            $conversation_history = array();
        }

        // Format conversation history for X.AI (same as OpenAI format)
        $formatted_conversation = array();

        $formatted_conversation[] = array(
            'role' => 'system',
            'content' => $system_prompt_instructions . " " . $relevant_content
        );

        foreach ($conversation_history as $message) {
            if (is_array($message) && isset($message['role']) && isset($message['content'])) {
                $role = $message['role'];
                if ($role === 'bot' || $role === 'agent') {
                    $role = 'assistant';
                }
                if (!in_array($role, ['system', 'assistant', 'user', 'function', 'tool'])) {
                    $role = 'user';
                }
                $formatted_conversation[] = array(
                    'role' => $role,
                    'content' => $message['content']
                );
            }
        }

        // Check if we can actually stream
        if (headers_sent() || !function_exists('curl_init')) {
            // Fallback to regular response with testing data
            //error_log("MxChat: X.AI streaming not possible, falling back to regular response");
            $regular_response = $this->mxchat_generate_response_xai(
                $selected_model,
                $xai_api_key,
                $conversation_history,
                $relevant_content,
                $session_id
            );
            
            // Save bot response to transcript
            if (!empty($regular_response) && !empty($session_id)) {
                $this->mxchat_save_chat_message($session_id, 'bot', $regular_response);
            }
            
            $response_data = [
                'text' => $regular_response,
                'html' => '',
                'session_id' => $session_id
            ];
            
            if ($testing_data !== null) {
                $response_data['testing_data'] = $testing_data;
                //error_log("MxChat Testing: Added testing data to X.AI fallback response");
            }
            
            header('Content-Type: application/json');
            echo json_encode($response_data);
            return true;
        }

        // Prepare the request body with stream: true
        $body = json_encode([
            'model' => $selected_model,
            'messages' => $formatted_conversation,
            'temperature' => 0.8,
            'stream' => true
        ]);

        // V2 retry-on-initial-connect: setup_streaming_headers is lazy-fired in WRITEFUNCTION.

        $captured_status_code = 0;
        $captured_body_pre_stream = '';
        $full_response = '';
        $stream_started = false;
        $buffer = '';
        $errno = 0;
        $http_code = 0;
        $max_attempts = $this->mxchat_retry_enabled() ? 3 : 1;
        $backoff_ms = array(0, 750, 2000);

        for ($attempt = 0; $attempt < $max_attempts; $attempt++) {
            if ($attempt > 0 && $backoff_ms[$attempt] > 0) {
                usleep($backoff_ms[$attempt] * 1000);
            }

            $captured_status_code = 0;
            $captured_body_pre_stream = '';
            $full_response = '';
            $stream_started = false;
            $buffer = '';

            $ch = curl_init();
            curl_setopt($ch, CURLOPT_URL, 'https://api.x.ai/v1/chat/completions');
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, false);
            curl_setopt($ch, CURLOPT_POST, true);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $body);
            curl_setopt($ch, CURLOPT_HTTPHEADER, array(
                'Content-Type: application/json',
                'Authorization: Bearer ' . $xai_api_key
            ));
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
            curl_setopt($ch, CURLOPT_TIMEOUT, 60);

            curl_setopt($ch, CURLOPT_HEADERFUNCTION, function($ch, $header) use (&$captured_status_code) {
                if ($captured_status_code === 0 && preg_match('#^HTTP/\S+\s+(\d+)\b#', $header, $m)) {
                    $captured_status_code = (int) $m[1];
                }
                return strlen($header);
            });

            curl_setopt($ch, CURLOPT_WRITEFUNCTION, function($ch, $data) use (&$full_response, &$stream_started, &$buffer, &$captured_status_code, &$captured_body_pre_stream, $testing_data) {
                if ($captured_status_code !== 0 && $captured_status_code !== 200) {
                    $captured_body_pre_stream .= $data;
                    return strlen($data);
                }

                if (!$this->streaming_headers_sent) {
                    $this->setup_streaming_headers();
                }

                if (!$stream_started && $testing_data !== null) {
                    echo "data: " . json_encode(['testing_data' => $testing_data]) . "\n\n";
                    flush();
                    $stream_started = true;
                }

                $buffer .= $data;
                $lines = explode("\n", $buffer);
                $buffer = array_pop($lines);

                foreach ($lines as $line) {
                    if (trim($line) === '') {
                        continue;
                    }
                    if (strpos($line, 'data: ') !== 0) {
                        continue;
                    }

                    $json_str = substr($line, 6);

                    if (trim($json_str) === '[DONE]') {
                        echo "data: [DONE]\n\n";
                        flush();
                        continue;
                    }

                    $json = json_decode(trim($json_str), true);
                    if ($json && isset($json['choices'][0]['delta']['content'])) {
                        $content = $json['choices'][0]['delta']['content'];
                        $full_response .= $content;
                        echo "data: " . json_encode(['content' => $content]) . "\n\n";
                        flush();
                    }
                }

                return strlen($data);
            });

            $response = curl_exec($ch);
            $errno = curl_errno($ch);
            $http_code = $captured_status_code !== 0 ? $captured_status_code : (int) curl_getinfo($ch, CURLINFO_HTTP_CODE);
            curl_close($ch);

            if (!$errno && $http_code === 200) {
                break;
            }

            $is_transient = $this->mxchat_is_transient_provider_error_raw($http_code, $captured_body_pre_stream, 'xai', $errno);
            $can_retry = !$this->streaming_headers_sent
                      && ($attempt + 1) < $max_attempts
                      && $is_transient;

            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log(sprintf(
                    '[MxChat] xai_stream initial-connect failure (attempt=%d/%d, status=%d, errno=%d, transient=%s, %s).',
                    $attempt + 1, $max_attempts, $http_code, $errno,
                    $is_transient ? 'yes' : 'no',
                    $can_retry ? 'Retrying.' : 'Giving up.'
                ));
            }

            if (!$can_retry) {
                break;
            }
        }

        if ($errno || $http_code !== 200) {
            return $this->mxchat_stream_emit_fallback(
                'xai',
                $this->mxchat_generate_response_xai($selected_model, $xai_api_key, $conversation_history, $relevant_content, $session_id),
                $session_id,
                $testing_data
            );
        }

        // Save the complete response to maintain chat persistence
        if (!empty($full_response) && !empty($session_id)) {
            // Prepare RAG context for streaming response
            $rag_context_for_storage = null;
            $has_rag_data = $this->last_similarity_analysis !== null && !empty($this->last_similarity_analysis['top_matches']);
            $has_action_data = isset($this->last_action_analysis) && !empty($this->last_action_analysis);

            if ($has_rag_data || $has_action_data) {
                $rag_context_for_storage = [];

                if ($has_rag_data) {
                    $rag_context_for_storage['top_matches'] = $this->last_similarity_analysis['top_matches'];
                    $rag_context_for_storage['approved_urls'] = $this->current_valid_urls ?? [];
                    $rag_context_for_storage['similarity_threshold'] = $this->last_similarity_analysis['threshold_used'] ?? 0.35;
                    $rag_context_for_storage['knowledge_base_type'] = $this->last_similarity_analysis['knowledge_base_type'] ?? 'WordPress Database';
                    $rag_context_for_storage['total_documents_checked'] = $this->last_similarity_analysis['total_checked'] ?? 0;
                }

                if ($has_action_data) {
                    $rag_context_for_storage['action_analysis'] = $this->last_action_analysis;
                }
            }
            $this->mxchat_save_chat_message($session_id, 'bot', $full_response, null, $rag_context_for_storage);
        }

        return true; // Indicate streaming completed successfully

    } catch (Exception $e) {
        return $this->mxchat_stream_emit_fallback(
            'xai',
            $this->mxchat_generate_response_xai($selected_model, $xai_api_key, $conversation_history, $relevant_content),
            $session_id,
            $testing_data
        );
    }
}
private function mxchat_generate_response_deepseek_stream($selected_model, $deepseek_api_key, $conversation_history, $relevant_content, $session_id, $testing_data = null) {
    try {
        // Get bot ID from session or request
        $bot_id = $this->get_current_bot_id($session_id);
        
        // Get system prompt instructions using centralized function
        $system_prompt_instructions = $this->get_system_instructions($bot_id, $session_id);
        
        // Ensure conversation_history is an array
        if (!is_array($conversation_history)) {
            $conversation_history = array();
        }

        // Format conversation history for DeepSeek
        $formatted_conversation = array();

        $formatted_conversation[] = array(
            'role' => 'system',
            'content' => $system_prompt_instructions . " " . $relevant_content
        );

        foreach ($conversation_history as $message) {
            if (is_array($message) && isset($message['role']) && isset($message['content'])) {
                $role = $message['role'];
                if ($role === 'bot' || $role === 'agent') {
                    $role = 'assistant';
                }
                if (!in_array($role, ['system', 'assistant', 'user', 'function', 'tool'])) {
                    $role = 'user';
                }
                $formatted_conversation[] = array(
                    'role' => $role,
                    'content' => $message['content']
                );
            }
        }

        // Check if we can actually stream
        if (headers_sent() || !function_exists('curl_init')) {
            // Fallback to regular response with testing data
            //error_log("MxChat: DeepSeek streaming not possible, falling back to regular response");
            $regular_response = $this->mxchat_generate_response_deepseek(
                $selected_model,
                $deepseek_api_key,
                $conversation_history,
                $relevant_content,
                $session_id
            );
            
            // Save bot response to transcript
            if (!empty($regular_response) && !empty($session_id)) {
                $this->mxchat_save_chat_message($session_id, 'bot', $regular_response);
            }
            
            $response_data = [
                'text' => $regular_response,
                'html' => '',
                'session_id' => $session_id
            ];
            
            if ($testing_data !== null) {
                $response_data['testing_data'] = $testing_data;
                //error_log("MxChat Testing: Added testing data to DeepSeek fallback response");
            }

            header('Content-Type: application/json');
            echo json_encode($response_data);
            return true;
        }

        // Prepare the request body with stream: true
        $body = json_encode([
            'model' => $selected_model,
            'messages' => $formatted_conversation,
            'temperature' => 0.8,
            'stream' => true,
            // DeepSeek V4 defaults to thinking mode ON (temperature ignored,
            // long silent reasoning before the first delta); the widget wants
            // the legacy deepseek-chat semantics = non-thinking.
            'thinking' => ['type' => 'disabled']
        ]);

        // V2 retry-on-initial-connect: setup_streaming_headers is lazy-fired in WRITEFUNCTION.

        $captured_status_code = 0;
        $captured_body_pre_stream = '';
        $full_response = '';
        $stream_started = false;
        $buffer = '';
        $errno = 0;
        $http_code = 0;
        $max_attempts = $this->mxchat_retry_enabled() ? 3 : 1;
        $backoff_ms = array(0, 750, 2000);

        for ($attempt = 0; $attempt < $max_attempts; $attempt++) {
            if ($attempt > 0 && $backoff_ms[$attempt] > 0) {
                usleep($backoff_ms[$attempt] * 1000);
            }

            $captured_status_code = 0;
            $captured_body_pre_stream = '';
            $full_response = '';
            $stream_started = false;
            $buffer = '';

            $ch = curl_init();
            curl_setopt($ch, CURLOPT_URL, 'https://api.deepseek.com/v1/chat/completions');
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, false);
            curl_setopt($ch, CURLOPT_POST, true);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $body);
            curl_setopt($ch, CURLOPT_HTTPHEADER, array(
                'Content-Type: application/json',
                'Authorization: Bearer ' . $deepseek_api_key
            ));
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
            curl_setopt($ch, CURLOPT_TIMEOUT, 60);

            curl_setopt($ch, CURLOPT_HEADERFUNCTION, function($ch, $header) use (&$captured_status_code) {
                if ($captured_status_code === 0 && preg_match('#^HTTP/\S+\s+(\d+)\b#', $header, $m)) {
                    $captured_status_code = (int) $m[1];
                }
                return strlen($header);
            });

            curl_setopt($ch, CURLOPT_WRITEFUNCTION, function($ch, $data) use (&$full_response, &$stream_started, &$buffer, &$captured_status_code, &$captured_body_pre_stream, $testing_data) {
                if ($captured_status_code !== 0 && $captured_status_code !== 200) {
                    $captured_body_pre_stream .= $data;
                    return strlen($data);
                }

                if (!$this->streaming_headers_sent) {
                    $this->setup_streaming_headers();
                }

                if (!$stream_started && $testing_data !== null) {
                    echo "data: " . json_encode(['testing_data' => $testing_data]) . "\n\n";
                    flush();
                    $stream_started = true;
                }

                $buffer .= $data;
                $lines = explode("\n", $buffer);
                $buffer = array_pop($lines);

                foreach ($lines as $line) {
                    if (trim($line) === '') {
                        continue;
                    }
                    if (strpos($line, 'data: ') !== 0) {
                        continue;
                    }

                    $json_str = substr($line, 6);

                    if (trim($json_str) === '[DONE]') {
                        echo "data: [DONE]\n\n";
                        flush();
                        continue;
                    }

                    $json = json_decode(trim($json_str), true);
                    if ($json && isset($json['choices'][0]['delta']['content'])) {
                        $content = $json['choices'][0]['delta']['content'];
                        $full_response .= $content;
                        echo "data: " . json_encode(['content' => $content]) . "\n\n";
                        flush();
                    }
                }

                return strlen($data);
            });

            $response = curl_exec($ch);
            $errno = curl_errno($ch);
            $http_code = $captured_status_code !== 0 ? $captured_status_code : (int) curl_getinfo($ch, CURLINFO_HTTP_CODE);
            curl_close($ch);

            if (!$errno && $http_code === 200) {
                break;
            }

            $is_transient = $this->mxchat_is_transient_provider_error_raw($http_code, $captured_body_pre_stream, 'openai', $errno);
            $can_retry = !$this->streaming_headers_sent
                      && ($attempt + 1) < $max_attempts
                      && $is_transient;

            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log(sprintf(
                    '[MxChat] deepseek_stream initial-connect failure (attempt=%d/%d, status=%d, errno=%d, transient=%s, %s).',
                    $attempt + 1, $max_attempts, $http_code, $errno,
                    $is_transient ? 'yes' : 'no',
                    $can_retry ? 'Retrying.' : 'Giving up.'
                ));
            }

            if (!$can_retry) {
                break;
            }
        }

        if ($errno || $http_code !== 200) {
            return $this->mxchat_stream_emit_fallback(
                'openai',
                $this->mxchat_generate_response_deepseek($selected_model, $deepseek_api_key, $conversation_history, $relevant_content, $session_id),
                $session_id,
                $testing_data
            );
        }

        // Save the complete response to maintain chat persistence
        if (!empty($full_response) && !empty($session_id)) {
            // Prepare RAG context for streaming response
            $rag_context_for_storage = null;
            $has_rag_data = $this->last_similarity_analysis !== null && !empty($this->last_similarity_analysis['top_matches']);
            $has_action_data = isset($this->last_action_analysis) && !empty($this->last_action_analysis);

            if ($has_rag_data || $has_action_data) {
                $rag_context_for_storage = [];

                if ($has_rag_data) {
                    $rag_context_for_storage['top_matches'] = $this->last_similarity_analysis['top_matches'];
                    $rag_context_for_storage['approved_urls'] = $this->current_valid_urls ?? [];
                    $rag_context_for_storage['similarity_threshold'] = $this->last_similarity_analysis['threshold_used'] ?? 0.35;
                    $rag_context_for_storage['knowledge_base_type'] = $this->last_similarity_analysis['knowledge_base_type'] ?? 'WordPress Database';
                    $rag_context_for_storage['total_documents_checked'] = $this->last_similarity_analysis['total_checked'] ?? 0;
                }

                if ($has_action_data) {
                    $rag_context_for_storage['action_analysis'] = $this->last_action_analysis;
                }
            }
            $this->mxchat_save_chat_message($session_id, 'bot', $full_response, null, $rag_context_for_storage);
        }

        return true; // Indicate streaming completed successfully

    } catch (Exception $e) {
        return $this->mxchat_stream_emit_fallback(
            'openai',
            $this->mxchat_generate_response_deepseek($selected_model, $deepseek_api_key, $conversation_history, $relevant_content),
            $session_id,
            $testing_data
        );
    }
}


/**
 * Extract a human-readable error message from a decoded provider response body.
 * Providers disagree on shape: OpenAI/Anthropic/Google nest it (error.message),
 * xAI returns a plain string under 'error'. Mirrors mxchat-vision's shipped
 * extract_provider_error(); deliberately hint-free in core (vision's too-small
 * image hint is an upload concern that doesn't apply here).
 *
 * @param mixed  $decoded_body Decoded JSON body (array), or whatever json_decode returned.
 * @param string $fallback     Message to return when no provider text is found.
 * @return string
 */
private function extract_provider_error($decoded_body, $fallback) {
    $message = '';
    if (isset($decoded_body['error']['message']) && is_string($decoded_body['error']['message']) && $decoded_body['error']['message'] !== '') {
        $message = $decoded_body['error']['message'];
    } elseif (isset($decoded_body['error']) && is_string($decoded_body['error']) && $decoded_body['error'] !== '') {
        $message = $decoded_body['error'];
    }

    if ($message === '') {
        return $fallback;
    }

    return $message;
}

/**
 * plan-4aa8e5: a provider 200 whose body parses to no text must never reach
 * the widget as a silent empty bot bubble. Standard error shape for that
 * case, preferring the body's own explanation — error.message first (the
 * 950731 passthrough pattern), then the Responses API's
 * incomplete_details.reason (e.g. "max_output_tokens") — before the generic
 * retry message.
 */
private function mxchat_empty_completion_error($decoded_body, $provider_label) {
    $reason = '';
    if (isset($decoded_body['error']['message']) && is_string($decoded_body['error']['message']) && $decoded_body['error']['message'] !== '') {
        $reason = $decoded_body['error']['message'];
    } elseif (isset($decoded_body['incomplete_details']['reason']) && is_string($decoded_body['incomplete_details']['reason']) && $decoded_body['incomplete_details']['reason'] !== '') {
        $reason = sprintf(__('response incomplete: %s', 'mxchat'), $decoded_body['incomplete_details']['reason']);
    }

    $message = ($reason !== '')
        ? sprintf(esc_html__('%1$s returned an empty response (%2$s). Please try again.', 'mxchat'), $provider_label, esc_html($reason))
        : sprintf(esc_html__('%s returned an empty response. Please try again.', 'mxchat'), $provider_label);

    return [
        'error' => $message,
        'error_code' => 'empty_completion',
        'provider' => strtolower($provider_label),
    ];
}

private function mxchat_generate_response_openrouter($selected_model, $openrouter_api_key, $conversation_history, $relevant_content, $session_id = '') {
    try {
        if (!is_array($conversation_history)) {
            $conversation_history = array();
        }

        $bot_id = $this->get_current_bot_id($session_id);
        $system_prompt_instructions = $this->get_system_instructions($bot_id, $session_id);
        
        $formatted_conversation = array();

        $formatted_conversation[] = array(
            'role' => 'system',
            'content' => $system_prompt_instructions . " " . $relevant_content
        );

        foreach ($conversation_history as $message) {
            if (is_array($message) && isset($message['role']) && isset($message['content'])) {
                $role = $message['role'];

                if ($role === 'bot' || $role === 'agent') {
                    $role = 'assistant';
                }
                if (!in_array($role, ['system', 'assistant', 'user'])) {
                    $role = 'user';
                }

                $formatted_conversation[] = array(
                    'role' => $role,
                    'content' => $message['content']
                );
            }
        }

        $body = json_encode([
            'model' => $selected_model,
            'messages' => $formatted_conversation,
            'temperature' => 1,
        ]);

        $args = [
            'body'        => $body,
            'headers'     => [
                'Content-Type' => 'application/json',
                'Authorization' => 'Bearer ' . $openrouter_api_key,
                'HTTP-Referer' => home_url(),
                'X-Title' => get_bloginfo('name'),
            ],
            'timeout'     => 60,
            'redirection' => 5,
            'blocking'    => true,
            'httpversion' => '1.0',
            'sslverify'   => true,
        ];

        $response = $this->mxchat_provider_call_with_retry('https://openrouter.ai/api/v1/chat/completions', $args, 'openai');

        if (is_wp_error($response)) {
            $error_message = $response->get_error_message();
            return [
                'error' => $this->mxchat_friendly_chat_error(0, $error_message, 'OpenRouter'),
                'error_code' => 'openrouter_connection_error',
                'provider' => 'openrouter'
            ];
        }

        $status_code = wp_remote_retrieve_response_code($response);
        if ($status_code !== 200) {
            $response_body = wp_remote_retrieve_body($response);
            $decoded_response = json_decode($response_body, true);
            
            $error_message = $this->extract_provider_error($decoded_response, 'HTTP Error ' . $status_code);

            return [
                'error' => esc_html__('OpenRouter API error: ', 'mxchat') . esc_html($error_message),
                'error_code' => 'openrouter_api_error',
                'provider' => 'openrouter',
                'status_code' => $status_code
            ];
        }

        $response_body = wp_remote_retrieve_body($response);
        $decoded_response = json_decode($response_body, true);

        if (isset($decoded_response['choices'][0]['message']['content'])) {
            $text = trim($decoded_response['choices'][0]['message']['content']);
            if ($text !== '') {
                return $text;
            }
            return $this->mxchat_empty_completion_error($decoded_response, 'OpenRouter');
        } else {
            return [
                'error' => esc_html__('Unexpected response format from OpenRouter.', 'mxchat'),
                'error_code' => 'openrouter_response_format_error',
                'provider' => 'openrouter'
            ];
        }
    } catch (Exception $e) {
        return [
            'error' => esc_html__('System error when processing OpenRouter request: ', 'mxchat') . esc_html($e->getMessage()),
            'error_code' => 'openrouter_exception',
            'provider' => 'openrouter'
        ];
    }
}

/**
 * Build a chat-bubble-safe message for a non-200 provider (chat) error.
 *
 * Visitors must NEVER see raw API internals (model names, key/billing/quota
 * text). Admins (manage_options) get an actionable hint — and, for the common
 * "model not available on this key" case, a direct pointer to change the model
 * (the site owner can fix it in one click). Anthropic returns model-access as a
 * 4xx with a message like "Claude Fable 5 is not available. Please use Opus 4.8."
 *
 * Provider-agnostic by design (reusable for the xai/gemini/deepseek branches),
 * but Anthropic is the confirmed, reproduced case wired up here (plan 1d3b0f).
 *
 * @param int    $http_code      HTTP status from the provider.
 * @param string $error_message  Raw provider error.message (may be empty).
 * @param string $provider_label Human provider name, e.g. 'Anthropic'.
 * @return string Message safe to render as a chat bubble.
 */
private function mxchat_friendly_chat_error($http_code, $error_message, $provider_label = '') {
    $raw = trim((string) $error_message);

    // Detect a model-access / availability problem the site owner can fix by
    // choosing a different model. (Anthropic phrasing + the common API shapes.)
    $low = strtolower($raw);
    $is_model_access = (strpos($low, 'not available') !== false)
        || (strpos($low, 'does not have access') !== false)
        || (strpos($low, 'do not have access') !== false)
        || (strpos($low, 'does not exist') !== false)          // OpenAI: "model `x` does not exist or you do not have access"
        || (strpos($low, 'model_not_found') !== false)
        || (strpos($low, 'not_found_error') !== false)
        || (strpos($low, 'model not found') !== false)          // xAI
        || (strpos($low, 'not found') !== false)                // Gemini: "models/x is not found for API version ..."
        || (strpos($low, 'permission_denied') !== false)        // Gemini gated model
        || (strpos($low, 'permission denied') !== false);

    if (current_user_can('manage_options')) {
        if ($is_model_access) {
            return $raw !== ''
                ? sprintf(
                    /* translators: %s: raw provider error detail */
                    esc_html__('The selected AI model isn\'t available on your API key. Choose another model in MxChat → Settings. (Details: %s)', 'mxchat'),
                    $raw
                  )
                : esc_html__('The selected AI model isn\'t available on your API key. Choose another model in MxChat → Settings.', 'mxchat');
        }
        return $raw !== ''
            ? sprintf(
                /* translators: 1: provider label, 2: raw provider error detail */
                esc_html__('The AI provider (%1$s) returned an error: %2$s. Check your model and API key in MxChat → Settings.', 'mxchat'),
                $provider_label !== '' ? $provider_label : esc_html__('AI', 'mxchat'),
                $raw
              )
            : esc_html__('The AI provider returned an error. Check your model and API key in MxChat → Settings.', 'mxchat');
    }

    // Visitors: friendly, generic, no internals leaked.
    return esc_html__('Sorry, I\'m having trouble responding right now. Please try again in a moment.', 'mxchat');
}

private function mxchat_generate_response_claude($selected_model, $claude_api_key, $conversation_history, $relevant_content, $session_id = '') {
    // Anthropic retired claude-opus-4-20250514 / claude-sonnet-4-20250514 on 2026-06-15.
    // Read-time rescue: remap a saved dead ID to the current equivalent before the API call.
    if ($selected_model === 'claude-opus-4-20250514') { $selected_model = 'claude-opus-4-8'; }
    elseif ($selected_model === 'claude-sonnet-4-20250514') { $selected_model = 'claude-sonnet-4-6'; }

        // Get bot ID from session or request
        $bot_id = $this->get_current_bot_id($session_id);
        
        // Get system prompt instructions using centralized function
        $system_prompt_instructions = $this->get_system_instructions($bot_id, $session_id);
        
    // Clean and validate conversation history
    foreach ($conversation_history as &$message) {
        // Convert bot and agent roles to assistant
        if ($message['role'] === 'bot' || $message['role'] === 'agent') {
            $message['role'] = 'assistant';
        }
        
        // Remove unsupported roles - Claude only supports 'assistant' and 'user'
        if (!in_array($message['role'], ['assistant', 'user'])) {
            $message['role'] = 'user';
        }

        // Ensure content field exists
        if (!isset($message['content']) || empty($message['content'])) {
            $message['content'] = '';
        }

        // Remove any unsupported fields
        $message = array_intersect_key($message, array_flip(['role', 'content']));
    }

    // Add relevant content as the latest user message
    $conversation_history[] = [
        'role' => 'user',
        'content' => $relevant_content
    ];

    // Build request body
    $payload = [
        'model' => $selected_model,
        'max_tokens' => 1000,
        'temperature' => 0.8,
        'messages' => $conversation_history,
        'system' => $system_prompt_instructions
    ];
    if ($this->mxchat_claude_omits_temperature($selected_model)) { unset($payload['temperature']); }
    $body = json_encode($payload);

    // Set up API request
    $args = [
        'body' => $body,
            'headers' => [
                'Content-Type' => 'application/json',
                'x-api-key' => $claude_api_key,
                'anthropic-version' => '2023-06-01'
            ],
        'timeout' => 60,
        'redirection' => 5,
        'blocking' => true,
        'httpversion' => '1.0',
        'sslverify' => true,
    ];

    // Make API request
    $response = $this->mxchat_provider_call_with_retry('https://api.anthropic.com/v1/messages', $args, 'anthropic');

    // Check for WordPress errors
    if (is_wp_error($response)) {
        //error_log("Claude API request error: " . $response->get_error_message());
        return "Sorry, there was an error connecting to the API.";
    }

    // Check HTTP response code
    $http_code = wp_remote_retrieve_response_code($response);
    if ($http_code !== 200) {
        $error_body = wp_remote_retrieve_body($response);
        //error_log("Claude API HTTP error: " . $http_code . " - " . $error_body);
        
        // Try to extract error message from response
        $error_data = json_decode($error_body, true);
        $error_message = isset($error_data['error']['message']) ?
            $error_data['error']['message'] :
            "HTTP error " . $http_code;

        // Surface an admin-actionable message (and a model-change pointer for the
        // model-access case) without leaking raw API internals to visitors. This
        // is the single chokepoint for BOTH the non-streaming and streaming Claude
        // paths (the stream's non-200 fallback re-enters this method). plan 1d3b0f.
        return $this->mxchat_friendly_chat_error($http_code, $error_message, 'Anthropic');
    }

    // Parse response
    $response_body = json_decode(wp_remote_retrieve_body($response), true);
    
    // Check for JSON decode errors
    if (json_last_error() !== JSON_ERROR_NONE) {
        //error_log("Claude API JSON decode error: " . json_last_error_msg());
        return "Sorry, there was an error processing the API response.";
    }

    // Extract and validate response content. claude-fable-5 prepends a
    // thinking block to content even with no thinking param — take the first
    // TEXT block rather than content[0].
    if (isset($response_body['content']) && is_array($response_body['content'])) {
        foreach ($response_body['content'] as $block) {
            // plan-4aa8e5: skip empty text blocks — a 200 whose only text
            // block trims to '' must not render as a silent empty bubble.
            if (isset($block['type'], $block['text']) && $block['type'] === 'text' && trim($block['text']) !== '') {
                return trim($block['text']);
            }
        }
        return $this->mxchat_empty_completion_error($response_body, 'Claude');
    }

    // Log unexpected response format
    //error_log("Claude API unexpected response format: " . print_r($response_body, true));
    return "Sorry, I received an unexpected response format from the API.";
}
private function mxchat_generate_response_openai($selected_model, $api_key, $conversation_history, $relevant_content, $session_id = '') {
    try {
        // Ensure conversation_history is an array
        if (!is_array($conversation_history)) {
            $conversation_history = array();
        }

        // Get bot ID from session or request. plan eb9c38: resolve the real bot
        // from the session (was hardcoded '' → always default bot on multi-bot
        // installs) and fix the undefined $session_id that fed get_system_instructions.
        $bot_id = $this->get_current_bot_id($session_id);

        // Get system prompt instructions using centralized function
        $system_prompt_instructions = $this->get_system_instructions($bot_id, $session_id);

        // Create a new array for the formatted conversation
        $formatted_conversation = array();

        // Add system message first
        $formatted_conversation[] = array(
            'role' => 'system',
            'content' => $system_prompt_instructions . " " . $relevant_content
        );

        // Add the rest of the conversation history
        foreach ($conversation_history as $message) {
            if (is_array($message) && isset($message['role']) && isset($message['content'])) {
                $role = $message['role'];

                // Convert roles to supported format
                if ($role === 'bot' || $role === 'agent') {
                    $role = 'assistant';
                }
                if (!in_array($role, ['system', 'assistant', 'user', 'function', 'tool'])) {
                    $role = 'user';
                }

                $formatted_conversation[] = array(
                    'role' => $role,
                    'content' => $message['content']
                );
            }
        }

        // Build request body with optimal settings for fast responses
        $request_body = [
            'model' => $selected_model,
            'messages' => $formatted_conversation,
            'temperature' => 1,
            'stream' => false
        ];

        // reasoning_effort — sourced from the core model catalog (plan-dcb71c);
        // frozen inline ladder lives in mxchat_reasoning_effort_fallback().
        $effort = $this->mxchat_reasoning_effort_for($selected_model, 'chat');
        if ($effort !== null) {
            $request_body['reasoning_effort'] = $effort;
        }

        $body = json_encode($request_body);

        $args = [
            'body'        => $body,
            'headers'     => [
                'Content-Type' => 'application/json',
                'Authorization' => 'Bearer ' . $api_key,
            ],
            'timeout'     => 60,
            'redirection' => 5,
            'blocking'    => true,
            'httpversion' => '1.0',
            'sslverify'   => true,
        ];

        $response = $this->mxchat_provider_call_with_retry('https://api.openai.com/v1/chat/completions', $args, 'openai');

        if (is_wp_error($response)) {
            $error_message = $response->get_error_message();
            return [
                'error' => $this->mxchat_friendly_chat_error(0, $error_message, 'OpenAI'),
                'error_code' => 'openai_connection_error',
                'provider' => 'openai'
            ];
        }

        $status_code = wp_remote_retrieve_response_code($response);
        if ($status_code !== 200) {
            $response_body = wp_remote_retrieve_body($response);
            $decoded_response = json_decode($response_body, true);
            
            $error_message = isset($decoded_response['error']['message']) 
                ? $decoded_response['error']['message'] 
                : 'HTTP Error ' . $status_code;
            
            $error_type = isset($decoded_response['error']['type']) 
                ? $decoded_response['error']['type'] 
                : 'unknown';
            
            // Handle specific error types
            switch ($error_type) {
                case 'invalid_request_error':
                    if (strpos($error_message, 'API key') !== false) {
                        return [
                            'error' => esc_html__('Invalid OpenAI API key. Please check your API key configuration.', 'mxchat'),
                            'error_code' => 'openai_invalid_api_key',
                            'provider' => 'openai'
                        ];
                    }
                    break;
                    
                case 'authentication_error':
                    return [
                        'error' => esc_html__('Authentication failed with OpenAI. Please check your API key.', 'mxchat'),
                        'error_code' => 'openai_auth_error',
                        'provider' => 'openai'
                    ];
                
                case 'rate_limit_exceeded':
                    return [
                        'error' => esc_html__('OpenAI rate limit exceeded. Please try again later.', 'mxchat'),
                        'error_code' => 'openai_rate_limit',
                        'provider' => 'openai'
                    ];
                    
                case 'quota_exceeded':
                    return [
                        'error' => esc_html__('OpenAI API quota exceeded. Please check your billing details.', 'mxchat'),
                        'error_code' => 'openai_quota_exceeded',
                        'provider' => 'openai'
                    ];
            }
            
            // Generic error fallback only — the typed cases above already produce
            // clean messages. Route the raw-tail generic case through the leak-safe
            // helper so visitors never see provider internals. plan 5da59a.
            return [
                'error' => $this->mxchat_friendly_chat_error($status_code, $error_message, 'OpenAI'),
                'error_code' => 'openai_api_error',
                'provider' => 'openai',
                'status_code' => $status_code
            ];
        }

        $response_body = wp_remote_retrieve_body($response);
        $decoded_response = json_decode($response_body, true);

        if (isset($decoded_response['choices'][0]['message']['content'])) {
            $text = trim($decoded_response['choices'][0]['message']['content']);
            if ($text !== '') {
                return $text;
            }
            return $this->mxchat_empty_completion_error($decoded_response, 'OpenAI');
        } else {
            return [
                'error' => esc_html__('Unexpected response format from OpenAI.', 'mxchat'),
                'error_code' => 'openai_response_format_error',
                'provider' => 'openai'
            ];
        }
    } catch (Exception $e) {
        return [
            'error' => esc_html__('System error when processing OpenAI request: ', 'mxchat') . esc_html($e->getMessage()),
            'error_code' => 'openai_exception',
            'provider' => 'openai'
        ];
    }
}

private function mxchat_generate_response_xai($selected_model, $xai_api_key, $conversation_history, $relevant_content, $session_id = '') {
    try {
        // Get bot ID from session or request
        $bot_id = $this->get_current_bot_id($session_id);
        
        // Get system prompt instructions using centralized function
        $system_prompt_instructions = $this->get_system_instructions($bot_id, $session_id);
        
        // Add system prompt to relevant content
    $content_with_instructions = $system_prompt_instructions . " " . $relevant_content;

    // Prepend system instructions to the conversation history
    array_unshift($conversation_history, [
        'role' => 'system',
        'content' => "Here are your instructions: " . $content_with_instructions
    ]);

    // Ensure consistency: Replace 'bot' and 'agent' roles with supported values
    foreach ($conversation_history as &$message) {
        if ($message['role'] === 'bot') {
            $message['role'] = 'assistant';
        } elseif ($message['role'] === 'agent') {
            // Tag the message as coming from a live agent
            $message['role'] = 'assistant';
            if (!isset($message['metadata'])) {
                $message['metadata'] = ['source' => 'live_agent'];
            }
        }

        // Ensure all roles are valid
        if (!in_array($message['role'], ['system', 'assistant', 'user', 'function', 'tool'])) {
            $message['role'] = 'user'; // Default to 'user'
        }
    }

    // Build the request body
    $body = json_encode([
        'model' => $selected_model,
        'messages' => $conversation_history,
        'temperature' => 0.8,
        'stream' => false
    ]);

    // Set up the API request
    $args = [
        'body'        => $body,
        'headers'     => [
            'Content-Type' => 'application/json',
            'Authorization' => 'Bearer ' . $xai_api_key,
        ],
        'timeout'     => 60,
        'redirection' => 5,
        'blocking'    => true,
        'httpversion' => '1.0',
        'sslverify'   => true,
    ];

    // Make the API request
    $response = $this->mxchat_provider_call_with_retry('https://api.x.ai/v1/chat/completions', $args, 'xai');

    // Process the response
    if (is_wp_error($response)) {
        $error_message = $response->get_error_message();
        //error_log('X.AI API Error: ' . $error_message);
        return [
            'error' => $this->mxchat_friendly_chat_error(0, $error_message, 'X.AI'),
            'error_code' => 'xai_connection_error',
            'provider' => 'xai'
        ];
    }

    $status_code = wp_remote_retrieve_response_code($response);
    if ($status_code !== 200) {
        $response_body = wp_remote_retrieve_body($response);
        $decoded_response = json_decode($response_body, true);

        // Log the full response for debugging
        //error_log('X.AI Error Response: ' . print_r($decoded_response, true));

        // Extract error message from X.AI's specific format
        $error_message = '';
        
        // Check for direct error string (as seen in your logs)
        if (isset($decoded_response['error']) && is_string($decoded_response['error'])) {
            $error_message = $decoded_response['error'];
        }
        // Check for nested error object (OpenAI style)
        elseif (isset($decoded_response['error']['message'])) {
            $error_message = $decoded_response['error']['message'];
        }
        // Check for top-level message
        elseif (isset($decoded_response['message'])) {
            $error_message = $decoded_response['message'];
        }
        // Fallback
        else {
            $error_message = 'HTTP Error ' . $status_code;
        }

        //error_log('X.AI API HTTP Error: ' . $status_code . ' - ' . $error_message);

        // Check for API key errors using string matching
        if (stripos($error_message, 'api key') !== false || 
            stripos($error_message, 'incorrect api key') !== false ||
            stripos($error_message, 'invalid api key') !== false) {
            return [
                'error' => esc_html__('Invalid X.AI API key. Please check your API key configuration.', 'mxchat'),
                'error_code' => 'xai_invalid_api_key',
                'provider' => 'xai'
            ];
        }

        // Authentication errors
        if ($status_code === 401 || $status_code === 403 ||
            stripos($error_message, 'auth') !== false) {
            return [
                'error' => esc_html__('Authentication failed with X.AI. Please check your API key.', 'mxchat') . ' ' . esc_html($error_message),
                'error_code' => 'xai_auth_error',
                'provider' => 'xai'
            ];
        }

        // Model errors — keep the canned category text as a prefix, but carry the
        // provider's extracted reason (e.g. "Model not found: ") so the owner
        // sees the specific model/reason instead of only the generic category.
        if (stripos($error_message, 'model') !== false) {
            return [
                'error' => esc_html__('Invalid model specified for X.AI. Please check your model configuration.', 'mxchat') . ' ' . esc_html($error_message),
                'error_code' => 'xai_invalid_model',
                'provider' => 'xai'
            ];
        }

        // Rate limit errors
        if ($status_code === 429 || 
            stripos($error_message, 'rate') !== false || 
            stripos($error_message, 'limit') !== false) {
            return [
                'error' => esc_html__('X.AI rate limit exceeded. Please try again later.', 'mxchat'),
                'error_code' => 'xai_rate_limit',
                'provider' => 'xai'
            ];
        }

        // Quota errors
        if (stripos($error_message, 'quota') !== false || 
            stripos($error_message, 'billing') !== false) {
            return [
                'error' => esc_html__('X.AI API quota exceeded. Please check your billing details.', 'mxchat'),
                'error_code' => 'xai_quota_exceeded',
                'provider' => 'xai'
            ];
        }

        // Server errors
        if ($status_code >= 500) {
            return [
                'error' => esc_html__('X.AI service is currently unavailable. Please try again later.', 'mxchat'),
                'error_code' => 'xai_service_unavailable',
                'provider' => 'xai'
            ];
        }

        // Generic error fallback. Route the user-facing text through the
        // leak-safe helper (admins get an actionable hint, visitors a generic
        // fallback) instead of echoing raw provider internals. Preserve the
        // structured contract (error_code/provider/status_code) for logging. plan 5da59a.
        return [
            'error' => $this->mxchat_friendly_chat_error($status_code, $error_message, 'xAI'),
            'error_code' => 'xai_api_error',
            'provider' => 'xai',
            'status_code' => $status_code
        ];
    }

    $response_body = wp_remote_retrieve_body($response);
    $decoded_response = json_decode($response_body, true);

    if (isset($decoded_response['choices'][0]['message']['content'])) {
        $text = trim($decoded_response['choices'][0]['message']['content']);
        if ($text !== '') {
            return $text;
        }
        return $this->mxchat_empty_completion_error($decoded_response, 'X.AI');
    } else {
        //error_log('X.AI API Response Format Error: ' . print_r($decoded_response, true));
        return [
            'error' => esc_html__('Unexpected response format from X.AI.', 'mxchat'),
            'error_code' => 'xai_response_format_error',
            'provider' => 'xai'
        ];
    }
} catch (Exception $e) {
    //error_log('X.AI Exception: ' . $e->getMessage());
    return [
        'error' => esc_html__('System error when processing X.AI request: ', 'mxchat') . esc_html($e->getMessage()),
        'error_code' => 'xai_exception',
        'provider' => 'xai'
    ];
}


}
private function mxchat_generate_response_deepseek($selected_model, $deepseek_api_key, $conversation_history, $relevant_content, $session_id = '') {
    try {
        // Ensure conversation_history is an array
        if (!is_array($conversation_history)) {
            $conversation_history = array();
        }

        // Get bot ID from session or request
        $bot_id = $this->get_current_bot_id($session_id);
        
        // Get system prompt instructions using centralized function
        $system_prompt_instructions = $this->get_system_instructions($bot_id, $session_id);
        
        // Create a new array for the formatted conversation
        $formatted_conversation = array();

        // Add system message first
        $formatted_conversation[] = array(
            'role' => 'system',
            'content' => $system_prompt_instructions . " " . $relevant_content
        );

        // Add the rest of the conversation history
        foreach ($conversation_history as $message) {
            if (is_array($message) && isset($message['role']) && isset($message['content'])) {
                $role = $message['role'];

                // Convert roles to supported format
                if ($role === 'bot' || $role === 'agent') {
                    $role = 'assistant';
                }
                if (!in_array($role, ['system', 'assistant', 'user', 'function', 'tool'])) {
                    $role = 'user';
                }

                $formatted_conversation[] = array(
                    'role' => $role,
                    'content' => $message['content']
                );
            }
        }

        $body = json_encode([
            'model' => $selected_model,
            'messages' => $formatted_conversation,
            'temperature' => 0.8,
            'stream' => false,
            // DeepSeek V4 defaults to thinking mode ON (temperature ignored,
            // slow reasoning-first responses); the widget wants the legacy
            // deepseek-chat semantics = non-thinking.
            'thinking' => ['type' => 'disabled']
        ]);

        $args = [
            'body'        => $body,
            'headers'     => [
                'Content-Type' => 'application/json',
                'Authorization' => 'Bearer ' . $deepseek_api_key,
            ],
            'timeout'     => 60,
            'redirection' => 5,
            'blocking'    => true,
            'httpversion' => '1.0',
            'sslverify'   => true,
        ];

        $response = $this->mxchat_provider_call_with_retry('https://api.deepseek.com/v1/chat/completions', $args, 'openai');

        if (is_wp_error($response)) {
            $error_message = $response->get_error_message();
            //error_log('DeepSeek API Error: ' . $error_message);
            return [
                'error' => $this->mxchat_friendly_chat_error(0, $error_message, 'DeepSeek'),
                'error_code' => 'deepseek_connection_error',
                'provider' => 'deepseek'
            ];
        }

        $status_code = wp_remote_retrieve_response_code($response);
        if ($status_code !== 200) {
            $response_body = wp_remote_retrieve_body($response);
            $decoded_response = json_decode($response_body, true);

            $error_message = isset($decoded_response['error']['message']) 
                ? $decoded_response['error']['message'] 
                : 'HTTP Error ' . $status_code;
                
            $error_type = isset($decoded_response['error']['type']) 
                ? $decoded_response['error']['type'] 
                : 'unknown';
                
            //error_log('DeepSeek API HTTP Error: ' . $status_code . ' - ' . $error_message);

            // Handle specific error types
            switch ($status_code) {
                case 401:
                    return [
                        'error' => esc_html__('Authentication failed with DeepSeek. Please check your API key.', 'mxchat'),
                        'error_code' => 'deepseek_auth_error',
                        'provider' => 'deepseek'
                    ];
                
                case 400:
                    if (strpos($error_message, 'API key') !== false) {
                        return [
                            'error' => esc_html__('Invalid DeepSeek API key. Please check your API key configuration.', 'mxchat'),
                            'error_code' => 'deepseek_invalid_api_key',
                            'provider' => 'deepseek'
                        ];
                    }
                    break;
                    
                case 429:
                    if (strpos($error_message, 'quota') !== false) {
                        return [
                            'error' => esc_html__('DeepSeek API quota exceeded. Please check your billing details.', 'mxchat'),
                            'error_code' => 'deepseek_quota_exceeded',
                            'provider' => 'deepseek'
                        ];
                    } else {
                        return [
                            'error' => esc_html__('DeepSeek rate limit exceeded. Please try again later.', 'mxchat'),
                            'error_code' => 'deepseek_rate_limit',
                            'provider' => 'deepseek'
                        ];
                    }
                    
                case 500:
                case 502:
                case 503:
                case 504:
                    return [
                        'error' => esc_html__('DeepSeek service is currently unavailable. Please try again later.', 'mxchat'),
                        'error_code' => 'deepseek_service_unavailable',
                        'provider' => 'deepseek'
                    ];
            }

            // Generic error fallback — leak-safe helper (see plan 5da59a / 1d3b0f).
            return [
                'error' => $this->mxchat_friendly_chat_error($status_code, $error_message, 'DeepSeek'),
                'error_code' => 'deepseek_api_error',
                'provider' => 'deepseek',
                'status_code' => $status_code
            ];
        }

        $response_body = wp_remote_retrieve_body($response);
        $decoded_response = json_decode($response_body, true);

        if (isset($decoded_response['choices'][0]['message']['content'])) {
            $text = trim($decoded_response['choices'][0]['message']['content']);
            if ($text !== '') {
                return $text;
            }
            return $this->mxchat_empty_completion_error($decoded_response, 'DeepSeek');
        } else {
            //error_log('DeepSeek API Response Format Error: ' . print_r($decoded_response, true));
            return [
                'error' => esc_html__('Unexpected response format from DeepSeek.', 'mxchat'),
                'error_code' => 'deepseek_response_format_error',
                'provider' => 'deepseek'
            ];
        }
    } catch (Exception $e) {
        //error_log('DeepSeek Exception: ' . $e->getMessage());
        return [
            'error' => esc_html__('System error when processing DeepSeek request: ', 'mxchat') . esc_html($e->getMessage()),
            'error_code' => 'deepseek_exception',
            'provider' => 'deepseek'
        ];
    }
}
private function mxchat_generate_response_gemini($selected_model, $gemini_api_key, $conversation_history, $relevant_content, $session_id = '') {
        // Read-time remap: gemini-3-pro-preview was shut down March 9, 2026.
        // Auto-rescue existing installs whose saved model is the dead ID.
        if ($selected_model === 'gemini-3-pro-preview') {
            $selected_model = 'gemini-3.1-pro-preview';
        }
        // Get bot ID from session or request
        $bot_id = $this->get_current_bot_id($session_id);
        
        // Get system prompt instructions using centralized function
        $system_prompt_instructions = $this->get_system_instructions($bot_id, $session_id);
        
    // Add system prompt to relevant content
    $content_with_instructions = $system_prompt_instructions . " " . $relevant_content;
    
    // Format messages for Gemini API
    $formatted_messages = [];
    
    // Add system message as the first user message with role prefix
    // Note: Gemini doesn't have a dedicated system role, so we use a prefixed user message
    $formatted_messages[] = [
        'role' => 'user',
        'parts' => [
            ['text' => "[System Instructions] " . $content_with_instructions]
        ]
    ];
    
    // Add model response to acknowledge system instructions
    $formatted_messages[] = [
        'role' => 'model',
        'parts' => [
            ['text' => "I understand and will follow these instructions."]
        ]
    ];
    
    // Process the rest of the conversation history
    $current_role = null;
    $current_parts = [];
    
    foreach ($conversation_history as $message) {
        // Skip the first system message as we already handled it
        if ($message['role'] === 'system') {
            continue;
        }
        
        // Map roles to Gemini format
        $gemini_role = '';
        if ($message['role'] === 'user') {
            $gemini_role = 'user';
        } else if (in_array($message['role'], ['assistant', 'bot', 'agent'])) {
            $gemini_role = 'model';
        } else {
            // Skip unsupported roles
            continue;
        }
        
        // If we have a new role, add the previous message
        if ($current_role !== null && $current_role !== $gemini_role && !empty($current_parts)) {
            $formatted_messages[] = [
                'role' => $current_role,
                'parts' => $current_parts
            ];
            $current_parts = [];
        }
        
        // Set current role and add text to parts
        $current_role = $gemini_role;
        $current_parts[] = ['text' => $message['content']];
    }
    
    // Add the last message if there's content
    if ($current_role !== null && !empty($current_parts)) {
        $formatted_messages[] = [
            'role' => $current_role,
            'parts' => $current_parts
        ];
    }
    
    // Built-in Web Search grounding for Gemini (plan 46b9ea).
    // The enable_web_search toggle historically routed ONLY to OpenAI's web_search
    // tool; for a Gemini chat model it was a silent no-op. Gemini grounds natively
    // (and free) via the Google Search tool, so when the toggle is on we attach it
    // here on the PLAIN dispatch path. The function-calling loop (mxchat_fc_loop_gemini)
    // is a SEPARATE path reached only when AI Tools are active, so grounding here
    // never double-fires with function calling.
    $web_search_enabled = isset($this->options['enable_web_search']) && $this->options['enable_web_search'] === 'on';
    // Gemini ids that do NOT support Google Search grounding (none today — every
    // shipped chat model is 2.x/3.x and grounds natively). Kept as the explicit
    // opt-out list mirroring the OpenAI $unsupported_web_search_models pattern.
    $gemini_unsupported_grounding = array();
    $grounding_active = $web_search_enabled && !in_array($selected_model, $gemini_unsupported_grounding, true);

    // Build the request body
    $request_payload = [
        'contents' => $formatted_messages,
        'generationConfig' => [
            'temperature' => 0.7,
            'topP' => 0.95,
            'topK' => 40,
            'maxOutputTokens' => 8192,
        ],
        'safetySettings' => [
            [
                'category' => 'HARM_CATEGORY_HARASSMENT',
                'threshold' => 'BLOCK_MEDIUM_AND_ABOVE'
            ],
            [
                'category' => 'HARM_CATEGORY_HATE_SPEECH',
                'threshold' => 'BLOCK_MEDIUM_AND_ABOVE'
            ],
            [
                'category' => 'HARM_CATEGORY_SEXUALLY_EXPLICIT',
                'threshold' => 'BLOCK_MEDIUM_AND_ABOVE'
            ],
            [
                'category' => 'HARM_CATEGORY_DANGEROUS_CONTENT',
                'threshold' => 'BLOCK_MEDIUM_AND_ABOVE'
            ]
        ]
    ];

    if ($grounding_active) {
        // Gemini 1.5 used the older google_search_retrieval shape; 2.0+ uses the
        // bare google_search tool. Branch by model family so a future 1.5 id still
        // grounds (no 1.5 ships today, so this resolves to google_search). The empty
        // tool config must serialize as a JSON object {}, not an array [].
        if (strpos($selected_model, 'gemini-1.5') !== false) {
            $request_payload['tools'] = [ ['google_search_retrieval' => new \stdClass()] ];
        } else {
            $request_payload['tools'] = [ ['google_search' => new \stdClass()] ];
        }
    }

    $body = json_encode($request_payload);

    // Prepare the API endpoint
    // Use v1beta for preview models (Gemini 3, experimental), v1 for stable models.
    // Grounding (the google_search tool) is a v1beta feature, so force v1beta whenever
    // it's active — otherwise a stable model on v1 would silently drop the tool.
    $api_version = ($grounding_active || strpos($selected_model, 'preview') !== false || strpos($selected_model, 'exp') !== false) ? 'v1beta' : 'v1';
    $api_endpoint = 'https://generativelanguage.googleapis.com/' . $api_version . '/models/' . $selected_model . ':generateContent?key=' . $gemini_api_key;
    
    // Set up the API request
    $args = [
        'body'        => $body,
        'headers'     => [
            'Content-Type' => 'application/json',
        ],
        'timeout'     => 60,
        'redirection' => 5,
        'blocking'    => true,
        'httpversion' => '1.0',
        'sslverify'   => true,
    ];
    
    // Make the API request
    $response = $this->mxchat_provider_call_with_retry($api_endpoint, $args, 'gemini');

    // Process the response
    if (is_wp_error($response)) {
        // plan b13282: route the transport-error string through the leak-safe helper
        // (admin-actionable, generic for visitors) instead of echoing the raw WP HTTP
        // error. http_code 0 = no HTTP response, so the helper uses the generic branch.
        return $this->mxchat_friendly_chat_error(0, $response->get_error_message(), 'Gemini');
    }
    
    $response_body = json_decode(wp_remote_retrieve_body($response), true);
    
    // Handle potential errors in the response. Gemini surfaces errors as a
    // 200/non-200 body with an `error` envelope; route the user-facing text
    // through the leak-safe helper (admin-actionable, no visitor leak) rather
    // than echoing the raw provider message. plan 5da59a.
    if (isset($response_body['error'])) {
        //error_log('Gemini API Error: ' . json_encode($response_body['error']));
        $gemini_error_message = isset($response_body['error']['message'])
            ? $response_body['error']['message']
            : 'Unknown error';
        $gemini_http_code = wp_remote_retrieve_response_code($response);
        return $this->mxchat_friendly_chat_error($gemini_http_code, $gemini_error_message, 'Gemini');
    }
    
    // Extract the response text
    if (isset($response_body['candidates'][0]['content']['parts'][0]['text'])) {
        $text = trim($response_body['candidates'][0]['content']['parts'][0]['text']);
        if ($text !== '') {
            return $text;
        }
        return $this->mxchat_empty_completion_error($response_body, 'Gemini');
    } else {
        //error_log('Unexpected Gemini API response format: ' . json_encode($response_body));
        return "Sorry, I couldn't process that request. The response format was unexpected.";
    }
}


public function test_streaming_request() {
    $options = get_option('mxchat_options', []);
    $model = $options['model'] ?? 'gpt-5.1-chat-latest';

    // Detect provider from model prefix
    $provider = strtolower(explode('-', $model)[0]);

    $sample_prompt = 'Hello! Can you stream this response back to me?';
    $messages = [['role' => 'user', 'content' => $sample_prompt]];
    $headers = [];
    $body = [];
    $url = '';
    $api_key = '';

    switch ($provider) {
        case 'gpt':
        case 'o1':
            $api_key = $options['api_key'] ?? '';
            if (empty($api_key)) return '❌ Missing API key for OpenAI';
            $url = 'https://api.openai.com/v1/chat/completions';
            $headers = [
                'Content-Type: application/json',
                'Authorization: Bearer ' . $api_key
            ];
            $body = [
                'model' => $model,
                'messages' => $messages,
                'stream' => true
            ];
            break;

        case 'claude':
            $api_key = $options['claude_api_key'] ?? '';
            if (empty($api_key)) return '❌ Missing API key for Claude';
            $url = 'https://api.anthropic.com/v1/messages';
            $headers = [
                'Content-Type: application/json',
                'x-api-key: ' . $api_key,
                'anthropic-version: 2023-06-01'
            ];
            $body = [
                'model' => $model,
                'messages' => $messages,
                'max_tokens' => 100,
                'stream' => true
            ];
            break;

        case 'grok':
            $api_key = $options['xai_api_key'] ?? '';
            if (empty($api_key)) return '❌ Missing API key for X.AI';
            $url = 'https://api.x.ai/v1/chat/completions';
            $headers = [
                'Content-Type: application/json',
                'Authorization: Bearer ' . $api_key
            ];
            $body = [
                'model' => $model,
                'messages' => $messages,
                'stream' => true
            ];
            break;

        case 'deepseek':
            if (empty($deepseek_api_key)) {
                $error_response = [
                    'error' => esc_html__('DeepSeek API key is not configured', 'mxchat'),
                    'error_code' => 'missing_deepseek_api_key'
                ];
                if ($testing_data !== null) {
                    $error_response['testing_data'] = $testing_data;
                }
                return $error_response;
            }
            if ($streaming) {
                return $this->mxchat_generate_response_deepseek_stream(
                    $selected_model,
                    $deepseek_api_key,
                    $conversation_history,
                    $relevant_content,
                    $session_id,
                    $testing_data  // Pass testing data
                );
            } else {
                $response = $this->mxchat_generate_response_deepseek(
                    $selected_model,
                    $deepseek_api_key,
                    $conversation_history,
                    $relevant_content,
                    $session_id
                );
            }
            break;

        case 'gemini':
            $api_key = $options['gemini_api_key'] ?? '';
            if (empty($api_key)) return '❌ Missing API key for Gemini';
            $url = 'https://generativelanguage.googleapis.com/v1beta/models/' . $model . ':streamGenerateContent?key=' . $api_key;
            $headers = ['Content-Type: application/json'];
            $body = [
                'contents' => [['role' => 'user', 'parts' => [['text' => $sample_prompt]]]],
                'generationConfig' => ['temperature' => 0.7]
            ];
            break;

        default:
            return '❌ Unsupported provider: ' . $provider;
    }

    // Do the actual streaming test
    $ch = curl_init($url);
    curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($body));
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_TIMEOUT, 15);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);

    $response = curl_exec($ch);
    $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    $error = curl_error($ch);
    curl_close($ch);

    if ($error) return "❌ cURL error: $error";
    if ($http_code !== 200) {
        $error_message = json_decode($response, true)['error']['message'] ?? 'Unknown';
        return "❌ HTTP $http_code: $error_message";
    }

    return true;
}

public function mxchat_dismiss_pre_chat_message() {
    // Get and sanitize the user identifier
    $user_id = $this->mxchat_get_user_identifier();
    $user_id = sanitize_key($user_id);

    // Set a transient to track that the user has dismissed the pre-chat message
    $transient_key = 'mxchat_pre_chat_message_dismissed_' . $user_id;
    set_transient($transient_key, true, DAY_IN_SECONDS);

    wp_send_json_success();
}

public function mxchat_check_pre_chat_message_status() {
    // Get and sanitize the user identifier
    $user_id = $this->mxchat_get_user_identifier();
    $user_id = sanitize_key($user_id);

    // Check if the transient exists (i.e., if the message was dismissed)
    $transient_key = 'mxchat_pre_chat_message_dismissed_' . $user_id;
    $dismissed = get_transient($transient_key);

    // Log the result to see if it's being set correctly
    //error_log("Check pre-chat message dismissed for $user_id: " . ($dismissed ? 'Yes' : 'No'));

    if ($dismissed) {
        wp_send_json_success(['dismissed' => true]);
    } else {
        wp_send_json_success(['dismissed' => false]);
    }

    wp_die();
}

private function mxchat_calculate_cosine_similarity($vectorA, $vectorB) {
        if (!is_array($vectorA) || !is_array($vectorB) || empty($vectorA) || empty($vectorB)) {
            return 0;
        }

        $dotProduct = array_sum(array_map(function ($a, $b) {
            return $a * $b;
        }, $vectorA, $vectorB));
        $normA = sqrt(array_sum(array_map(function ($a) {
            return $a * $a;
        }, $vectorA)));
        $normB = sqrt(array_sum(array_map(function ($b) {
            return $b * $b;
        }, $vectorB)));

        if ($normA == 0 || $normB == 0) {
            return 0;
        }

        return $dotProduct / ($normA * $normB);
    }


public function mxchat_enqueue_scripts_styles($force = false) {
    // Idempotency guard (plan-915355): the smart-asset-loading safety net in
    // render_chatbot_shortcode() may invoke this method a second time (or on
    // every shortcode render). Run the body at most once per request so the
    // nonce, dynamic-settings merge, delayed transient write, and wp_footer
    // loader action never happen twice.
    static $did_run = false;
    if ($did_run) {
        return;
    }

    // Smart asset loading gate (plan-915355, opt-in, default OFF — toggle in
    // MxChat → Settings → Optimization → Script Loading). When enabled and the
    // shared display decision says the widget won't render on this request,
    // skip all front-end assets. $force (the shortcode safety net) bypasses
    // the gate because at that point the widget IS rendering. Note: bail
    // WITHOUT setting $did_run, so a later forced call can still enqueue.
    if (!$force
        && class_exists('MxChat_Public')
        && MxChat_Public::is_smart_asset_loading_enabled()
        && !MxChat_Public::should_load_assets()) {
        return;
    }

    $did_run = true;

    // Fetch options from the database first to check loading strategy
    $this->options = get_option('mxchat_options');
    $loading_strategy = isset($this->options['script_loading_strategy']) ? $this->options['script_loading_strategy'] : 'default';

    // Always enqueue CSS immediately
    wp_enqueue_style(
        'mxchat-chat-css',
        plugin_dir_url(__FILE__) . '../css/chat-style.css',
        array(),
        MXCHAT_VERSION
    );

    // Handle script loading based on strategy
    if ($loading_strategy === 'default' || $loading_strategy === 'defer') {
        // Enqueue the script normally
        wp_enqueue_script(
            'mxchat-chat-js',
            plugin_dir_url(__FILE__) . '../js/chat-script.js',
            array('jquery'),
            MXCHAT_VERSION,
            true
        );

        // Add defer attribute if strategy is 'defer'
        if ($loading_strategy === 'defer') {
            wp_script_add_data('mxchat-chat-js', 'strategy', 'defer');
        }
    } else {
        // For delay or interaction-based loading, we'll use a custom loader
        // Don't enqueue the main script - we'll load it dynamically
        add_action('wp_footer', array($this, 'mxchat_output_delayed_script_loader'), 99);
    }

    $prompts_options = get_option('mxchat_prompts_options', array());

    // Check if AI theme is active - if so, skip inline colors in JavaScript
    $theme_options = get_option('mxchat_theme_options', array());
    $ai_theme_active = !empty($theme_options['active_ai_theme_css']);
    $has_bot_theme_assignments = !empty($theme_options['bot_theme_assignments']);
    $skip_inline_colors = $ai_theme_active || $has_bot_theme_assignments;

    // Prepare settings for JavaScript
    $style_settings = array(
        'ajax_url' => admin_url('admin-ajax.php'),
        // The chat-send nonce is now fetched per-request from /wp-json/mxchat/v1/nonce
        // (plan-6a68c9) so it never sits in cached HTML. We still emit a nonce here
        // as a one-shot fallback for the first interaction on a fresh page load
        // (so the very first chat-send doesn't need to wait for a REST round-trip),
        // but the widget refetches before each subsequent send.
        'nonce' => wp_create_nonce('mxchat_chat_send'),
        'rest_url' => esc_url_raw(trailingslashit(rest_url('mxchat/v1'))),
        'contextual_awareness_toggle' => isset($this->options['contextual_awareness_toggle']) ? $this->options['contextual_awareness_toggle'] : 'off',
        'link_target_toggle' => $this->options['link_target_toggle'] ?? 'off',
        'complianz_toggle' => isset($this->options['complianz_toggle']) && $this->options['complianz_toggle'] === 'on',
        'user_message_bg_color' => $this->options['user_message_bg_color'] ?? '#fff',
        'user_message_font_color' => $this->options['user_message_font_color'] ?? '#212121',
        'bot_message_bg_color' => $this->options['bot_message_bg_color'] ?? '#212121',
        'bot_message_font_color' => $this->options['bot_message_font_color'] ?? '#fff',
        'top_bar_bg_color' => $this->options['top_bar_bg_color'] ?? '#212121',
        'send_button_font_color' => $this->options['send_button_font_color'] ?? '#212121',
        'close_button_color' => $this->options['close_button_color'] ?? '#fff',
        'chatbot_background_color' => $this->options['chatbot_background_color'] ?? '#212121',
        'chatbot_bg_color' => $this->options['chatbot_bg_color'] ?? '#fff',
        'icon_color' => $this->options['icon_color'] ?? '#fff',
        'chat_input_font_color' => $this->options['chat_input_font_color'] ?? '#212121',
        'chat_persistence_toggle' => $this->options['chat_persistence_toggle'] ?? 'off',
        'appendWidgetToBody' => $this->options['append_to_body'] ?? 'off',
        'live_agent_message_bg_color' => $this->options['live_agent_message_bg_color'] ?? '#ffffff',
        'live_agent_message_font_color' => $this->options['live_agent_message_font_color'] ?? '#333333',
        'mode_indicator_bg_color' => $this->options['mode_indicator_bg_color'] ?? '#767676',
        'mode_indicator_font_color' => $this->options['mode_indicator_font_color'] ?? '#ffffff',
        'toolbar_icon_color' => $this->options['toolbar_icon_color'] ?? '#212121',
        'use_pinecone' => $prompts_options['mxchat_use_pinecone'] ?? '0',
        'email_collection_enabled' => $this->options['enable_email_block'] ?? 'off', // FIXED
        'initial_email_state' => null, // Also fixed this undefined variable
        'skip_email_check' => true,
        'pinecone_enabled' => isset($prompts_options['mxchat_use_pinecone']) && $prompts_options['mxchat_use_pinecone'] === '1',
        'skip_inline_colors' => $skip_inline_colors,
        'bot_theme_assignments' => $theme_options['bot_theme_assignments'] ?? array(),
    );

    // Behavior gates + labels (model, streaming, rate-limit copy, toolbar,
    // print/transcript, satisfaction rating) come from the shared
    // dynamic-settings method so this inline payload and the first-open
    // refresh endpoint can never drift (plan-32db95).
    $style_settings = array_merge($style_settings, $this->get_dynamic_widget_settings());

    // For normal/defer loading, use wp_localize_script.
    // For delayed loading, nothing is localized or stored here: the delayed
    // loader (mxchat_output_delayed_script_loader) rebuilds the full settings
    // array inline from options and never reads any stored copy.
    if ($loading_strategy === 'default' || $loading_strategy === 'defer') {
        wp_localize_script('mxchat-chat-js', 'mxchatChat', $style_settings);
    } else {
        // Late-render fallback (plan-915355): when the shortcode safety net
        // forces this method during/after wp_footer (footer widget areas, late
        // builder regions), the wp_footer:99 loader action registered above may
        // already be past its slot. Emit the loader inline right now; its
        // emitted-once guard prevents double output if :99 still fires.
        if ($force && did_action('wp_footer')) {
            $this->mxchat_output_delayed_script_loader();
        }
    }
}

/**
 * Output the delayed script loader for performance optimization
 */
public function mxchat_output_delayed_script_loader() {
    // Emitted-once guard (plan-915355): this can now be reached both via the
    // wp_footer:99 action and via the late-render inline fallback in
    // mxchat_enqueue_scripts_styles(). The loader must print exactly once.
    static $emitted = false;
    if ($emitted) {
        return;
    }
    $emitted = true;

    $this->options = get_option('mxchat_options');
    $loading_strategy = isset($this->options['script_loading_strategy']) ? $this->options['script_loading_strategy'] : 'default';
    $script_url = plugin_dir_url(__FILE__) . '../js/chat-script.js?ver=' . MXCHAT_VERSION;

    // Get the stored settings
    $prompts_options = get_option('mxchat_prompts_options', array());
    $theme_options = get_option('mxchat_theme_options', array());
    $ai_theme_active = !empty($theme_options['active_ai_theme_css']);
    $has_bot_theme_assignments = !empty($theme_options['bot_theme_assignments']);
    $skip_inline_colors = $ai_theme_active || $has_bot_theme_assignments;

    $style_settings = array(
        'ajax_url' => admin_url('admin-ajax.php'),
        // Per-request nonce — see plan-6a68c9; widget fetches via /wp-json/mxchat/v1/nonce
        // before each send. This inline value is a one-shot fallback for the first interaction.
        'nonce' => wp_create_nonce('mxchat_chat_send'),
        'rest_url' => esc_url_raw(trailingslashit(rest_url('mxchat/v1'))),
        'contextual_awareness_toggle' => isset($this->options['contextual_awareness_toggle']) ? $this->options['contextual_awareness_toggle'] : 'off',
        'link_target_toggle' => $this->options['link_target_toggle'] ?? 'off',
        'complianz_toggle' => isset($this->options['complianz_toggle']) && $this->options['complianz_toggle'] === 'on',
        'user_message_bg_color' => $this->options['user_message_bg_color'] ?? '#fff',
        'user_message_font_color' => $this->options['user_message_font_color'] ?? '#212121',
        'bot_message_bg_color' => $this->options['bot_message_bg_color'] ?? '#212121',
        'bot_message_font_color' => $this->options['bot_message_font_color'] ?? '#fff',
        'top_bar_bg_color' => $this->options['top_bar_bg_color'] ?? '#212121',
        'send_button_font_color' => $this->options['send_button_font_color'] ?? '#212121',
        'close_button_color' => $this->options['close_button_color'] ?? '#fff',
        'chatbot_background_color' => $this->options['chatbot_background_color'] ?? '#212121',
        'chatbot_bg_color' => $this->options['chatbot_bg_color'] ?? '#fff',
        'icon_color' => $this->options['icon_color'] ?? '#fff',
        'chat_input_font_color' => $this->options['chat_input_font_color'] ?? '#212121',
        'chat_persistence_toggle' => $this->options['chat_persistence_toggle'] ?? 'off',
        'appendWidgetToBody' => $this->options['append_to_body'] ?? 'off',
        'live_agent_message_bg_color' => $this->options['live_agent_message_bg_color'] ?? '#ffffff',
        'live_agent_message_font_color' => $this->options['live_agent_message_font_color'] ?? '#333333',
        'mode_indicator_bg_color' => $this->options['mode_indicator_bg_color'] ?? '#767676',
        'mode_indicator_font_color' => $this->options['mode_indicator_font_color'] ?? '#ffffff',
        'toolbar_icon_color' => $this->options['toolbar_icon_color'] ?? '#212121',
        'use_pinecone' => $prompts_options['mxchat_use_pinecone'] ?? '0',
        'email_collection_enabled' => $this->options['enable_email_block'] ?? 'off',
        'initial_email_state' => null,
        'skip_email_check' => true,
        'pinecone_enabled' => isset($prompts_options['mxchat_use_pinecone']) && $prompts_options['mxchat_use_pinecone'] === '1',
        'skip_inline_colors' => $skip_inline_colors,
        'bot_theme_assignments' => $theme_options['bot_theme_assignments'] ?? array(),
    );

    // Behavior gates + labels (model, streaming, rate-limit copy, toolbar,
    // print/transcript, satisfaction rating) come from the shared
    // dynamic-settings method so this inline payload and the first-open
    // refresh endpoint can never drift (plan-32db95).
    $style_settings = array_merge($style_settings, $this->get_dynamic_widget_settings());

    // Determine delay time based on strategy
    $delay_ms = 0;
    switch ($loading_strategy) {
        case 'delay_1s':
            $delay_ms = 1000;
            break;
        case 'delay_3s':
            $delay_ms = 3000;
            break;
        case 'delay_5s':
            $delay_ms = 5000;
            break;
    }

    ?>
    
    setup_fallback_rate_limit_system();
            return;
        }
        
        // Check if cron is already scheduled - if so, don't mess with it
        if (wp_next_scheduled('mxchat_reset_rate_limits')) {
            //error_log('MxChat: Rate limit cron already scheduled, skipping setup');
            return;
        }
        
        // Clear any orphaned hooks (but don't loop indefinitely)
        $hooks_to_clear = [
            'mxchat_reset_rate_limits',
            'mxchat_reset_hourly_rate_limits',
            'mxchat_reset_daily_rate_limits',
            'mxchat_reset_weekly_rate_limits',
            'mxchat_reset_monthly_rate_limits'
        ];
        
        foreach ($hooks_to_clear as $hook) {
            // Only clear a maximum of 3 instances to prevent infinite loops
            $cleared = 0;
            while (wp_next_scheduled($hook) && $cleared < 3) {
                wp_clear_scheduled_hook($hook);
                $cleared++;
            }
        }
        
        // Small delay after clearing
        usleep(100000); // 0.1 seconds
        
        // Try to schedule the event
        $initial_time = time() + 300; // Start in 5 minutes
        $result = wp_schedule_event($initial_time, 'hourly', 'mxchat_reset_rate_limits');

        if ($result === false) {
            //error_log('MxChat: Failed to schedule cron, using fallback system');
            $this->setup_fallback_rate_limit_system();
        } else {
            if (defined('MXCHAT_DEV_MODE') && MXCHAT_DEV_MODE) {
                error_log('MxChat: rate-limit reset cron event was missing and has been re-scheduled');
            }
        }
        
    } catch (Exception $e) {
        //error_log('MxChat: Cron setup exception: ' . $e->getMessage());
        $this->setup_fallback_rate_limit_system();
    }
}

/**
 * Try alternative cron scheduling methods
 */
private function try_alternative_cron_scheduling($initial_time) {
    try {
        // Method 1: Try with current time instead of future time
        $result1 = wp_schedule_event(time(), 'hourly', 'mxchat_reset_rate_limits');
        if ($result1 !== false) {
            //error_log('MxChat: Alternative method 1 (current time) succeeded');
            return true;
        }
        
        // Method 2: Try with a different interval
        $result2 = wp_schedule_event($initial_time, 'daily', 'mxchat_reset_rate_limits');
        if ($result2 !== false) {
            //error_log('MxChat: Alternative method 2 (daily interval) succeeded');
            return true;
        }
        
        // Method 3: Try wp_schedule_single_event first, then recurring
        $result3 = wp_schedule_single_event($initial_time, 'mxchat_reset_rate_limits');
        if ($result3 !== false) {
            //error_log('MxChat: Alternative method 3 (single event) succeeded');
            // Schedule the next one manually in the handler
            return true;
        }
        
        return false;
        
    } catch (Exception $e) {
        //error_log('MxChat: Alternative cron scheduling exception: ' . $e->getMessage());
        return false;
    }
}

/**
 * Enhanced fallback rate limit system
 */
private function setup_fallback_rate_limit_system() {
    // Idempotence matters here: with setup_rate_limit_cron_jobs() hooked to
    // admin_init, a DISABLE_WP_CRON site reaches this on every guard pass.
    // Unconditionally rewriting mxchat_next_rate_limit_check to now+3600 would
    // slide the deadline forward forever and the fallback reset would never
    // fire. Only initialize the deadline on a genuine transition into fallback
    // mode (or if it's somehow missing).
    $already_active = get_option('mxchat_use_fallback_rate_limits', false);

    // Set a flag to use database-based rate limit cleanup
    update_option('mxchat_use_fallback_rate_limits', true);

    // Schedule a one-time check to happen on the next plugin load
    if (!$already_active || !get_option('mxchat_next_rate_limit_check', 0)) {
        update_option('mxchat_next_rate_limit_check', time() + 3600);
    }

    // Also set up a more frequent fallback check (every 4 hours)
    update_option('mxchat_fallback_check_interval', 4 * 3600);

    //error_log('MxChat: Fallback rate limit system activated');
}

/**
 * Enhanced fallback check method
 * NOTE: mxchat_check_fallback_rate_limits() in mxchat-basic.php is a second
 * implementation of this same check — if either changes, change both.
 */
public function check_fallback_rate_limits() {
    $use_fallback = get_option('mxchat_use_fallback_rate_limits', false);
    
    if (!$use_fallback) {
        return; // Regular cron is working
    }
    
    $next_check = get_option('mxchat_next_rate_limit_check', 0);
    $check_interval = get_option('mxchat_fallback_check_interval', 3600);
    
    if (time() >= $next_check) {
        //error_log('MxChat: Running fallback rate limit cleanup');
        $this->mxchat_reset_rate_limits();
        
        // Schedule next check
        update_option('mxchat_next_rate_limit_check', time() + $check_interval);
    }
}
/**
 * Enhanced rate limit check that includes fallback cleanup and bot-specific rate limits
 */
public function check_rate_limit() {
    // Check if we need to run fallback cleanup
    $use_fallback = get_option('mxchat_use_fallback_rate_limits', false);
    $next_check = get_option('mxchat_next_rate_limit_check', 0);
    
    if ($use_fallback && time() >= $next_check) {
        $this->mxchat_reset_rate_limits();
        update_option('mxchat_next_rate_limit_check', time() + 3600); // Next hour
    }
    
    // Get bot ID from current request context
    $bot_id = isset($_POST['bot_id']) ? sanitize_key($_POST['bot_id']) : 'default';
    
    // Get bot-specific options (includes rate limits if overridden)
    $bot_options = $this->get_bot_options($bot_id);
    $current_options = !empty($bot_options) ? $bot_options : $this->options;
    
    // Use bot-specific rate limits if available, otherwise fall back to default
    $rate_limits_source = isset($current_options['rate_limits']) ? $current_options['rate_limits'] : get_option('mxchat_options', [])['rate_limits'] ?? [];

    // -------------------------------------------------------------------
    // Whole-chatbot global cap (independent of role). Evaluated FIRST so
    // it acts as a hard ceiling across all users + all roles. Default is
    // 'unlimited' so existing installs are unchanged. Counter key drops
    // both  and  segments — single pool per bot.
    // -------------------------------------------------------------------
    $global_cfg = isset($current_options['rate_limits_global']) && is_array($current_options['rate_limits_global'])
        ? $current_options['rate_limits_global']
        : (isset(get_option('mxchat_options', [])['rate_limits_global']) ? get_option('mxchat_options', [])['rate_limits_global'] : []);
    $global_limit_raw = isset($global_cfg['limit']) ? (string) $global_cfg['limit'] : 'unlimited';
    $global_timeframe = isset($global_cfg['timeframe']) ? (string) $global_cfg['timeframe'] : 'daily';
    if ($global_limit_raw !== '' && $global_limit_raw !== 'unlimited' && (int) $global_limit_raw >= 1) {
        $bot_id_for_global = isset($_POST['bot_id']) ? sanitize_key($_POST['bot_id']) : 'default';
        $safe_bot_global   = preg_replace('/[^a-zA-Z0-9_]/', '_', $bot_id_for_global);
        $global_option     = 'mxchat_chat_limit_' . $safe_bot_global . '_global';
        $global_data       = get_option($global_option, ['count' => 0, 'timestamp' => time()]);
        if ((int) $global_data['count'] === 0) {
            $global_data['timestamp'] = time();
            update_option($global_option, $global_data);
        }
        $now = time();
        $ts  = (int) $global_data['timestamp'];
        $reset = false;
        switch ($global_timeframe) {
            case 'hourly':  $reset = ($now - $ts) >= 3600;    break;
            case 'daily':   $reset = ($now - $ts) >= 86400;   break;
            case 'weekly':  $reset = ($now - $ts) >= 604800;  break;
            case 'monthly': $reset = ($now - $ts) >= 2592000; break;
        }
        if ($reset) {
            $global_data = ['count' => 0, 'timestamp' => $now];
            update_option($global_option, $global_data);
        }
        if ((int) $global_data['count'] >= (int) $global_limit_raw) {
            $global_msg = !empty($global_cfg['message'])
                ? $global_cfg['message']
                : __('This chatbot has reached its message limit. Please try again later.', 'mxchat');
            return [
                'error'   => true,
                'message' => $this->process_rate_limit_message_html($global_msg),
            ];
        }
        // Reserve the slot for this request. Per-role check below also increments
        // its own counter — that is intentional, both ceilings apply independently.
        $global_data['count']++;
        update_option($global_option, $global_data);
    }

    // Determine user role or if logged out
    if (is_user_logged_in()) {
        $user = wp_get_current_user();
        $user_id = $user->ID;
        
        // Get the user's primary role using reset() to safely get the first element
        $user_roles = $user->roles;
        
        // Safely get the first role regardless of array key structure
        if (!empty($user_roles) && is_array($user_roles)) {
            $role = reset($user_roles); // This safely gets the first element regardless of key
        } else {
            $role = 'subscriber'; // Default to subscriber if no role found
        }
    } else {
        $role = 'logged_out';
        // Use IP address for non-logged-in users
        $user_id = $this->get_client_ip();
    }
    
    // Check if rate limits are configured for this role
    if (!isset($rate_limits_source[$role])) {
        return true; // No limit set for this role
    }
    
    $limit = $rate_limits_source[$role]['limit'];
    
    // If unlimited, return true immediately
    if ($limit === 'unlimited') {
        return true;
    }
    
    // Get the option name for this user/role with safer naming (include bot_id for bot-specific limits)
    $safe_role = preg_replace('/[^a-zA-Z0-9_]/', '_', $role);
    $safe_user_id = preg_replace('/[^a-zA-Z0-9_]/', '_', $user_id);
    $safe_bot_id = preg_replace('/[^a-zA-Z0-9_]/', '_', $bot_id);
    
    // Include bot_id in option name so each bot has separate rate limits
    $option_name = 'mxchat_chat_limit_' . $safe_bot_id . '_' . $safe_role . '_' . $safe_user_id;
    
    // Get the counter data
    $limit_data = get_option($option_name, ['count' => 0, 'timestamp' => time()]);
    
    // If first request or counter reset needed, set the initial timestamp
    if ($limit_data['count'] === 0) {
        $limit_data['timestamp'] = time();
        update_option($option_name, $limit_data);
    }
    
    // Get the timeframe
    $timeframe = isset($rate_limits_source[$role]['timeframe']) ? 
        $rate_limits_source[$role]['timeframe'] : 'daily';
    
    // Check if the counter needs to be reset based on timeframe
    $current_time = time();
    $timestamp = $limit_data['timestamp'];
    $should_reset = false;
    
    switch ($timeframe) {
        case 'hourly':
            $should_reset = ($current_time - $timestamp) >= 3600; // 1 hour
            break;
        case 'daily':
            $should_reset = ($current_time - $timestamp) >= 86400; // 24 hours
            break;
        case 'weekly':
            $should_reset = ($current_time - $timestamp) >= 604800; // 7 days
            break;
        case 'monthly':
            $should_reset = ($current_time - $timestamp) >= 2592000; // 30 days
            break;
    }
    
    // Reset the counter if the timeframe has passed
    if ($should_reset) {
        $limit_data = ['count' => 0, 'timestamp' => $current_time];
        update_option($option_name, $limit_data);
    }
    
    // Check if user has exceeded their limit
    if ($limit_data['count'] >= intval($limit)) {
        // Get the custom message for this role
        $message = !empty($rate_limits_source[$role]['message']) 
            ? $rate_limits_source[$role]['message'] 
            : __('Rate limit exceeded. Please try again later.', 'mxchat');
        
        // Add timeframe information to the message if placeholders exist
        $timeframe_label = '';
        switch ($timeframe) {
            case 'hourly':
                $timeframe_label = __('hour', 'mxchat');
                break;
            case 'daily':
                $timeframe_label = __('day', 'mxchat');
                break;
            case 'weekly':
                $timeframe_label = __('week', 'mxchat');
                break;
            case 'monthly':
                $timeframe_label = __('month', 'mxchat');
                break;
        }
        
        // Replace placeholders in the message
        $message = str_replace(
            ['{limit}', '{count}', '{remaining}', '{timeframe}'],
            [intval($limit), $limit_data['count'], max(0, intval($limit) - $limit_data['count']), $timeframe_label],
            $message
        );
        
        // Process HTML links in the message
        $message = $this->process_rate_limit_message_html($message);
        
        // Return error with the processed message
        return [
            'error' => true,
            'message' => $message
        ];
    }
    
    // Increment the counter
    $limit_data['count']++;
    update_option($option_name, $limit_data);
    
    return true;
}

/**
 * Enhanced rate limit reset with better error handling
 */
public function mxchat_reset_rate_limits() {
    try {
        global $wpdb;
        $all_options = get_option('mxchat_options', []);
        $current_time = time();
        
        // Get rate limit options with a safer query and limit
        $option_names = $wpdb->get_col(
            $wpdb->prepare(
                "SELECT option_name FROM {$wpdb->options} 
                 WHERE option_name LIKE %s 
                 LIMIT 1000",
                'mxchat_chat_limit_%'
            )
        );
        
        if (empty($option_names)) {
            return;
        }
        
        $processed_count = 0;
        $max_processing_time = 30; // Maximum 30 seconds
        $start_time = time();
        
        foreach ($option_names as $option_name) {
            // Check processing time limit
            if ((time() - $start_time) > $max_processing_time) {
                //error_log('MxChat: Rate limit reset timeout after processing ' . $processed_count . ' entries');
                break;
            }
            
            // Parse the option name more safely
            if (!preg_match('/^mxchat_chat_limit_(.+)_(.+)$/', $option_name, $matches)) {
                continue;
            }
            
            $role_and_user = $matches[1] . '_' . $matches[2];
            $parts = explode('_', $role_and_user);
            
            if (count($parts) < 2) {
                continue;
            }
            
            // Extract role (everything except the last part which is user ID)
            $user_id_part = array_pop($parts);
            $role = implode('_', $parts);
            
            // Skip if role doesn't exist in our settings
            if (!isset($all_options['rate_limits'][$role])) {
                // Clean up orphaned entries
                delete_option($option_name);
                continue;
            }
            
            $timeframe = $all_options['rate_limits'][$role]['timeframe'] ?? 'daily';
            $limit_data = get_option($option_name);
            
            if (!$limit_data || !is_array($limit_data) || !isset($limit_data['timestamp'])) {
                // Clean up invalid entries
                delete_option($option_name);
                continue;
            }
            
            $timestamp = $limit_data['timestamp'];
            $should_reset = false;
            
            // Determine if we should reset based on the timeframe
            switch ($timeframe) {
                case 'hourly':
                    $should_reset = ($current_time - $timestamp) >= 3600;
                    break;
                case 'daily':
                    $should_reset = ($current_time - $timestamp) >= 86400;
                    break;
                case 'weekly':
                    $should_reset = ($current_time - $timestamp) >= 604800;
                    break;
                case 'monthly':
                    $should_reset = ($current_time - $timestamp) >= 2592000;
                    break;
            }
            
            // Reset the counter if the timeframe has passed
            if ($should_reset) {
                delete_option($option_name);
                wp_cache_delete($option_name, 'options');
                $processed_count++;
            }
        }
        
        // Clean up any orphaned cache entries
        wp_cache_delete('mxchat_all_chat_limits', 'options');
        
        //error_log("MxChat: Rate limit reset completed. Processed {$processed_count} entries.");
        
    } catch (Exception $e) {
        //error_log('MxChat: Rate limit reset error: ' . $e->getMessage());
    }
}


/**
 * Process HTML links in rate limit messages
 * 
 * @param string $message The rate limit message
 * @return string The processed message with safe HTML links
 */
private function process_rate_limit_message_html($message) {
    // Return original message if empty
    if (empty($message)) {
        return $message;
    }
    
    // First, convert markdown links to HTML
    $message = $this->convert_markdown_links($message);
    
    // Then, auto-convert any remaining plain URLs to links
    $message = $this->auto_link_urls($message);
    
    // Allow basic HTML tags for links and formatting
    $allowed_tags = [
        'a' => [
            'href' => true,
            'target' => true,
            'rel' => true,
            'title' => true,
            'class' => true
        ],
        'strong' => [],
        'em' => [],
        'br' => [],
        'b' => [],
        'i' => [],
        'span' => ['class' => true]
    ];
    
    // Sanitize but allow the specified HTML tags
    $processed_message = wp_kses($message, $allowed_tags);
    
    // If wp_kses stripped everything, return the original message as plain text
    if (empty($processed_message) && !empty($message)) {
        // Strip all HTML and return plain text as fallback
        return wp_strip_all_tags($message);
    }
    
    return $processed_message;
}

/**
 * Convert markdown links to HTML
 * 
 * @param string $text The text to process
 * @return string The text with markdown links converted to HTML
 */
private function convert_markdown_links($text) {
    // Return original text if empty
    if (empty($text)) {
        return $text;
    }
    
    // Pattern to match markdown links: [text](url)
    $pattern = '/\[([^\]]+)\]\(([^)]+)\)/';
    
    $processed_text = preg_replace_callback($pattern, function($matches) {
        $link_text = $matches[1];
        $url = $matches[2];
        
        // Clean up any trailing punctuation from the URL
        $url = rtrim($url, '.,;:!?');
        
        // Sanitize the link text and URL
        $safe_text = esc_html($link_text);
        $safe_url = esc_url($url);
        
        // Create the HTML link
        return '' . $safe_text . '';
    }, $text);
    
    // If preg_replace_callback failed, return original text
    if ($processed_text === null) {
        return $text;
    }
    
    return $processed_text;
}

/**
 * Auto-convert plain URLs to clickable links
 * 
 * @param string $text The text to process
 * @return string The text with URLs converted to links
 */
private function auto_link_urls($text) {
    // Return original text if empty
    if (empty($text)) {
        return $text;
    }
    
    // Simple pattern that avoids complex lookbehinds
    // This will match URLs that are not already inside href attributes or markdown links
    $pattern = '/(?"\')\]]+/i';
    
    $processed_text = preg_replace_callback($pattern, function($matches) {
        $url = $matches[0];
        // Clean up any trailing punctuation that might have been captured
        $url = rtrim($url, '.,;:!?');
        
        // Add target="_blank" and rel="noopener noreferrer" for security
        return '' . esc_html($url) . '';
    }, $text);
    
    // If preg_replace_callback failed, return original text
    if ($processed_text === null) {
        return $text;
    }
    
    return $processed_text;
}


// Helper function to get client IP address
private function get_client_ip() {
    // Check for shared internet/ISP IP
    if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
        return sanitize_text_field($_SERVER['HTTP_CLIENT_IP']);
    }
    
    // Check for IPs passing through proxies
    if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
        // Use the first value in the comma-separated list
        $forwarded_for = explode(',', sanitize_text_field($_SERVER['HTTP_X_FORWARDED_FOR']));
        return trim($forwarded_for[0]);
    }
    
    if (!empty($_SERVER['REMOTE_ADDR'])) {
        return sanitize_text_field($_SERVER['REMOTE_ADDR']);
    }
    
    // Fallback
    return 'unknown';
}

/**
 * AJAX handler to get system information for testing panel
 */
/**
 * AJAX handler to get system information for testing panel
 */
public function mxchat_get_system_info() {
    // Verify nonce for security
    if (!wp_verify_nonce($_POST['nonce'], 'mxchat_test_nonce')) {
        wp_send_json_error(['message' => 'Invalid nonce']);
        return;
    }
    
    // Only allow admin users
    if (!current_user_can('administrator')) {
        wp_send_json_error(['message' => 'Unauthorized']);
        return;
    }
    
    // Get system prompt from options
    $system_prompt = isset($this->options['system_prompt_instructions']) 
        ? $this->options['system_prompt_instructions'] 
        : 'No system prompt configured';
    
    // Get selected model
    $selected_model = isset($this->options['model']) ? $this->options['model'] : 'gpt-5.1-chat-latest';
    
    // Check if OpenRouter is being used
    $is_openrouter = ($selected_model === 'openrouter');
    $openrouter_model = '';
    
    if ($is_openrouter) {
        // Get the actual OpenRouter model that's selected
        $openrouter_model = isset($this->options['openrouter_selected_model']) 
            ? $this->options['openrouter_selected_model'] 
            : 'No OpenRouter model selected';
        
        // Update selected_model display to show both
        $selected_model = 'OpenRouter: ' . $openrouter_model;
    }
    
    // Get API key status (just check if they exist, don't expose the keys)
    $api_status = [];
    $api_status['openai'] = !empty($this->options['api_key']);
    $api_status['claude'] = !empty($this->options['claude_api_key']);
    $api_status['gemini'] = !empty($this->options['gemini_api_key']);
    $api_status['xai'] = !empty($this->options['xai_api_key']);
    $api_status['deepseek'] = !empty($this->options['deepseek_api_key']);
    $api_status['openrouter'] = !empty($this->options['openrouter_api_key']);
    
    wp_send_json_success([
        'system_prompt' => $system_prompt,
        'selected_model' => $selected_model,
        'is_openrouter' => $is_openrouter,
        'openrouter_model' => $openrouter_model,
        'api_status' => $api_status
    ]);
}

/**
 * AJAX handler to get similarity threshold
 */
public function mxchat_get_similarity_threshold() {
    // Verify nonce for security
    if (!wp_verify_nonce($_POST['nonce'], 'mxchat_test_nonce')) {
        wp_send_json_error(['message' => 'Invalid nonce']);
        return;
    }
    
    // Only allow admin users
    if (!current_user_can('administrator')) {
        wp_send_json_error(['message' => 'Unauthorized']);
        return;
    }
    
    // Get similarity threshold from main options (default 35%)
    $similarity_threshold = isset($this->options['similarity_threshold']) 
        ? ((int) $this->options['similarity_threshold']) / 100 
        : 0.35;
    
    wp_send_json_success([
        'threshold' => $similarity_threshold,
        'threshold_percentage' => ($similarity_threshold * 100) . '%'
    ]);
}

/**
 * AJAX handler to get knowledge base status
 */
public function mxchat_get_kb_status() {
    // Verify nonce for security
    if (!wp_verify_nonce($_POST['nonce'], 'mxchat_test_nonce')) {
        wp_send_json_error(['message' => 'Invalid nonce']);
        return;
    }

    // Only allow admin users
    if (!current_user_can('administrator')) {
        wp_send_json_error(['message' => 'Unauthorized']);
        return;
    }

    // Check OpenAI Vector Store first (takes priority)
    $vectorstore_options = get_option('mxchat_openai_vectorstore_options', array());
    $use_vectorstore = (isset($vectorstore_options['mxchat_use_openai_vectorstore']) && $vectorstore_options['mxchat_use_openai_vectorstore'] === '1');

    if ($use_vectorstore) {
        $vectorstore_ids = $vectorstore_options['mxchat_openai_vectorstore_ids'] ?? '';
        $id_count = !empty($vectorstore_ids) ? count(array_filter(array_map('trim', explode(',', $vectorstore_ids)))) : 0;

        $kb_info = [
            'type' => 'OpenAI Vector Store',
            'status' => 'Active',
            'documents' => $id_count > 0 ? $id_count . ' vector store' . ($id_count > 1 ? 's' : '') . ' configured' : 'No vector stores configured'
        ];

        wp_send_json_success($kb_info);
        return;
    }

    // Check Pinecone vs WordPress
    $addon_options = get_option('mxchat_pinecone_addon_options', array());
    $use_pinecone = (isset($addon_options['mxchat_use_pinecone']) && $addon_options['mxchat_use_pinecone'] === '1');

    $kb_info = [
        'type' => $use_pinecone ? 'Pinecone' : 'WordPress Database',
        'status' => 'Active'
    ];

    // Get document count
    if ($use_pinecone) {
        $kb_info['documents'] = 'Connected to Pinecone';
        $kb_info['api_configured'] = !empty($addon_options['mxchat_pinecone_api_key']);
    } else {
        // Count documents in WordPress database
        global $wpdb;
        $table_name = $wpdb->prefix . 'mxchat_system_prompt_content';
        $count = $wpdb->get_var("SELECT COUNT(*) FROM {$table_name}");
        $kb_info['documents'] = $count ? $count . ' documents' : 'No documents';
    }

    wp_send_json_success($kb_info);
}

/**
 * AJAX handler to start a completely fresh session (NEW - replaces old clear session)
 */
public function mxchat_start_fresh_session() {
    // Verify nonce for security
    if (!wp_verify_nonce($_POST['nonce'], 'mxchat_test_nonce')) {
        wp_send_json_error(['message' => 'Invalid nonce']);
        return;
    }
    
    // Only allow admin users
    if (!current_user_can('administrator')) {
        wp_send_json_error(['message' => 'Unauthorized']);
        return;
    }
    
    $old_session_id = isset($_POST['old_session_id']) ? sanitize_text_field($_POST['old_session_id']) : '';
    $new_session_id = isset($_POST['new_session_id']) ? sanitize_text_field($_POST['new_session_id']) : '';
    
    if (empty($old_session_id)) {
        wp_send_json_error(['message' => 'Old session ID required']);
        return;
    }
    
    // If no new session ID provided, generate one
    if (empty($new_session_id)) {
        // Cryptographically strong session id (plan-0c17b5). Prefix preserved
        // exactly (other code pattern-matches on 'mxchat_chat_'). random_bytes
        // is guaranteed on all supported PHP (7+).
        $new_session_id = 'mxchat_chat_' . bin2hex(random_bytes(16));
    }
    
    // Clear ALL data associated with the old session
    $this->clear_complete_session_data($old_session_id);
    
    // Initialize the new session
    $this->initialize_fresh_session($new_session_id);
    
    wp_send_json_success([
        'message' => 'Fresh session started successfully',
        'new_session_id' => $new_session_id,
        'old_session_id' => $old_session_id
    ]);
}

/**
 * Clear ALL data associated with a session (ENHANCED)
 */
private function clear_complete_session_data($session_id) {
    // Clear chat history
    delete_option("mxchat_history_{$session_id}");
    
    // Clear chat mode
    delete_option("mxchat_mode_{$session_id}");
    
    // Clear any PDF/Word transients
    $this->clear_pdf_transients($session_id);
    if (method_exists($this, 'clear_word_transients')) {
        $this->clear_word_transients($session_id);
    }
    
    // Archive the session's per-conversation Slack channel before its option
    // is deleted (plan 7458a7 — covers transcript-retention cleanup paths).
    // Toggle-gated + shared-channel-guarded inside the helper; best-effort.
    $stale_channel = get_option("mxchat_channel_{$session_id}", '');
    if ($stale_channel !== '') {
        $this->mxchat_maybe_archive_conversation_channel($session_id, $stale_channel);
    }

    // Clear agent-related data
    delete_option("mxchat_channel_{$session_id}");
    delete_option("mxchat_thread_{$session_id}");
    delete_option("mxchat_agent_name_{$session_id}");
    delete_option("mxchat_email_{$session_id}");
    
    // Clear any recommendation flow state
    delete_option("mxchat_sr_flow_state_{$session_id}");
    
    // Clear any cached embeddings or context
    delete_transient("mxchat_context_{$session_id}");
    delete_transient("mxchat_last_query_{$session_id}");
    
    // Clear any testing data
    delete_transient("mxchat_testing_data_{$session_id}");
    
    // Clear any rate limiting data for this session
    delete_transient("mxchat_rate_limit_{$session_id}");
    
    // Clear any other session-specific transients
    delete_transient("mxchat_waiting_for_pdf_url_{$session_id}");
    delete_transient("mxchat_include_pdf_in_context_{$session_id}");
    delete_transient("mxchat_include_word_in_context_{$session_id}");

    // Clear form addon state (pending forms and submitted forms)
    delete_option("mxchat_pending_form_{$session_id}");
    delete_option("mxchat_submitted_forms_{$session_id}");

    //error_log("MxChat: Cleared all data for session: {$session_id}");
}

/**
 * Initialize a fresh session with default data
 */
private function initialize_fresh_session($session_id) {
    // Set default chat mode
    update_option("mxchat_mode_{$session_id}", 'ai');
    
    //error_log("MxChat: Initialized fresh session: {$session_id}");
}

/**
 * Helper method to clear Word document transients (if you have Word support)
 */
private function clear_word_transients($session_id) {
    delete_transient('mxchat_word_url_' . $session_id);
    delete_transient('mxchat_word_filename_' . $session_id);
    delete_transient('mxchat_word_embeddings_' . $session_id);
    delete_transient('mxchat_include_word_in_context_' . $session_id);
}

/**
 * Simplified testing data capture method (CLEANED UP)
 */
private function capture_testing_data($user_embedding, $message, $session_id) {
    // Only capture for admin users
    if (!current_user_can('administrator')) {
        return null;
    }
    
    $testing_data = [
        'query' => $message,
        'timestamp' => time(),
        'top_matches' => [],
        'action_matches' => [] //   Add action matches
    ];
    
    // Get similarity threshold
    $similarity_threshold = isset($this->options['similarity_threshold']) 
        ? ((int) $this->options['similarity_threshold']) / 100 
        : 0.35;
    
    $testing_data['similarity_threshold'] = $similarity_threshold;
    
    // Use the real similarity analysis if available
    if ($this->last_similarity_analysis !== null) {
        $testing_data['knowledge_base_type'] = $this->last_similarity_analysis['knowledge_base_type'];
        $testing_data['top_matches'] = $this->last_similarity_analysis['top_matches'];
        $testing_data['total_documents_checked'] = $this->last_similarity_analysis['total_checked'] ?? 0;
    } else {
        // Fallback: determine knowledge base type
        $addon_options = get_option('mxchat_pinecone_addon_options', array());
        $use_pinecone = (isset($addon_options['mxchat_use_pinecone']) && $addon_options['mxchat_use_pinecone'] === '1');
        
        $testing_data['knowledge_base_type'] = $use_pinecone ? 'Pinecone' : 'WordPress Database';
    }
    
    //   Include action analysis if available
    if (isset($this->last_action_analysis) && !empty($this->last_action_analysis)) {
        $testing_data['action_matches'] = $this->last_action_analysis;
        
        // Clear it after capturing to avoid stale data
        $this->last_action_analysis = null;
    }
    
    return $testing_data;
}


/**
 *   Track URL clicks from chatbot responses
 */
public function mxchat_track_url_click() {
    // Verify nonce for security
    if (!isset($_POST['nonce']) || !MxChat_Integrator::mxchat_verify_chat_send_nonce($_POST['nonce'])) {
        wp_send_json_error(['message' => 'Invalid nonce']);
        wp_die();
    }
    
    $session_id = isset($_POST['session_id']) ? sanitize_text_field($_POST['session_id']) : '';
    $clicked_url = isset($_POST['url']) ? esc_url_raw($_POST['url']) : '';
    $message_context = isset($_POST['message_context']) ? sanitize_textarea_field($_POST['message_context']) : '';
    
    if (empty($session_id) || empty($clicked_url)) {
        wp_send_json_error(['message' => 'Missing required data']);
        wp_die();
    }
    
    global $wpdb;
    $table_name = $wpdb->prefix . 'mxchat_url_clicks';
    
    // Insert click tracking record
    $wpdb->insert(
        $table_name,
        [
            'session_id' => $session_id,
            'clicked_url' => $clicked_url,
            'message_context' => $message_context,
            'click_timestamp' => current_time('mysql', 1),
            'user_ip' => $_SERVER['REMOTE_ADDR'],
            'user_agent' => $_SERVER['HTTP_USER_AGENT']
        ]
    );
    
    wp_send_json_success(['message' => 'Click tracked']);
    wp_die();
}

/**
 *   Get URL click analytics for a session
 */
public function mxchat_get_url_clicks($session_id) {
    global $wpdb;
    $table_name = $wpdb->prefix . 'mxchat_url_clicks';
    
    $clicks = $wpdb->get_results($wpdb->prepare(
        "SELECT * FROM $table_name WHERE session_id = %s ORDER BY click_timestamp ASC",
        $session_id
    ));
    
    return $clicks;
}
/**
 *   Track the originating page where chat was started
 */
public function mxchat_track_originating_page() {
    // Verify nonce
    if (!isset($_POST['nonce']) || !MxChat_Integrator::mxchat_verify_chat_send_nonce($_POST['nonce'])) {
        wp_send_json_error(['message' => 'Invalid nonce']);
        wp_die();
    }
    
    $session_id = isset($_POST['session_id']) ? sanitize_text_field($_POST['session_id']) : '';
    $page_url = isset($_POST['page_url']) ? esc_url_raw($_POST['page_url']) : '';
    $page_title = isset($_POST['page_title']) ? sanitize_text_field($_POST['page_title']) : '';
    
    if (empty($session_id)) {
        wp_send_json_error(['message' => 'Missing session ID']);
        wp_die();
    }
    
    global $wpdb;
    $table_name = $wpdb->prefix . 'mxchat_chat_transcripts';
    
    // Check if we've already tracked for this session
    $existing = $wpdb->get_var($wpdb->prepare(
        "SELECT COUNT(*) FROM $table_name 
         WHERE session_id = %s 
         AND originating_page_url IS NOT NULL",
        $session_id
    ));
    
    if ($existing > 0) {
        wp_send_json_success(['message' => 'Already tracked']);
        wp_die();
    }
    
    // Update the first message in this session with originating page info
    $wpdb->query($wpdb->prepare(
        "UPDATE $table_name 
         SET originating_page_url = %s, 
             originating_page_title = %s 
         WHERE session_id = %s 
         ORDER BY timestamp ASC 
         LIMIT 1",
        $page_url,
        $page_title,
        $session_id
    ));
    
    wp_send_json_success(['message' => 'Originating page tracked']);
    wp_die();
}

/**
 * Validate and clean URLs from AI response
 * Removes any URLs that aren't in the knowledge base
 * 
 * @param string $response_text The AI-generated response
 * @param array $valid_urls Array of URLs from the knowledge base
 * @return string Cleaned response with invalid URLs removed/flagged
 */
private function validate_and_clean_urls($response_text, $valid_urls, $session_id = null, $bot_id = null) {
    /**
     * Filter the list of URLs treated as valid (allowlisted) BEFORE the
     * response URL sanitizer strips any link not in the list. Lets a site
     * owner / developer whitelist links their custom function-calling tools
     * return (e.g. session or speaker pages), which are otherwise absent from
     * the RAG/system-prompt-derived list and get stripped to plain text.
     *
     * Purely additive: with no hook registered, apply_filters returns
     * $valid_urls untouched, so there is zero behavior change for anyone who
     * does not use the filter. Applied before the empty-check so a hooked
     * allowlist can participate.  (plan-mxchat-20260710-13a471)
     *
     * @param array       $valid_urls URLs already known-valid (RAG + system prompt).
     * @param string|null $session_id Current chat session id, if available.
     * @param string|null $bot_id     Current bot id, if available.
     */
    $valid_urls = apply_filters('mxchat_valid_urls', $valid_urls, $session_id, $bot_id);

    // A bad mu-plugin returning a non-array (or non-string entries) must never
    // fatal the response path — coerce defensively before any use.
    if (!is_array($valid_urls)) {
        $valid_urls = array();
    }
    $valid_urls = array_values(array_filter($valid_urls, static function ($u) {
        return is_string($u) && $u !== '';
    }));

    // If no valid URLs provided or empty response, return as-is
    if (empty($valid_urls) || empty($response_text)) {
        //error_log("Validation skipped - empty valid_urls or response");
        return $response_text;
    }
    
    // Extract all URLs from the AI response
    // This regex matches http:// and https:// URLs
    preg_match_all(
        '#\bhttps?://[^\s<>"\')\]]+#i', 
        $response_text, 
        $matches
    );
    
    // If no URLs found in response, return as-is
    if (empty($matches[0])) {
        //error_log("No URLs found in response");
        return $response_text;
    }
    
    $found_urls = $matches[0];
    $cleaned_response = $response_text;
    $removed_count = 0;
    
    // Normalize valid URLs for comparison (remove trailing slashes, fragments, etc.)
    $normalized_valid_urls = array_map(function($url) {
        // Remove trailing slash
        $url = rtrim($url, '/');
        // Remove URL fragments (#section)
        $url = preg_replace('/#.*$/', '', $url);
        // Remove trailing punctuation that might have been captured
        $url = rtrim($url, '.,;:!?');
        return $url;
    }, $valid_urls);
    
    //error_log("Normalized valid URLs: " . print_r($normalized_valid_urls, true));
    
    foreach ($found_urls as $found_url) {
        // Clean up the found URL (remove trailing punctuation that might have been captured)
        $clean_found_url = rtrim($found_url, '.,;:!?)');
        
        // DEBUG: Log each URL being checked
        //error_log("Checking found URL: " . $found_url);
        
        // Normalize for comparison
        $normalized_found = rtrim($clean_found_url, '/');
        $normalized_found = preg_replace('/#.*$/', '', $normalized_found);
        
        //error_log("Normalized found URL: " . $normalized_found);
        
        // Check if this URL exists in our valid URLs list
        $is_valid = false;
        
        //error_log("Starting validation checks for: " . $normalized_found);
        
        // First, try exact match
        if (in_array($normalized_found, $normalized_valid_urls)) {
            $is_valid = true;
            //error_log("EXACT MATCH FOUND");
        } else {
            //error_log("No exact match, checking variations...");
            // If no exact match, check if it's a variation (with query params, etc.)
            foreach ($normalized_valid_urls as $valid_url) {
                //error_log("  Comparing against valid URL: " . $valid_url);
                
                // Check if the found URL starts with a valid URL (handles query params)
                if (strpos($normalized_found, $valid_url) === 0) {
                    // Check what comes after the valid URL
                    $remainder = substr($normalized_found, strlen($valid_url));
                    
                    // Only valid if:
                    // 1. Exact match (remainder is empty)
                    // 2. Query params (starts with ?)
                    // 3. Fragment (starts with #)
                    if (empty($remainder) || $remainder[0] === '?' || $remainder[0] === '#') {
                        $is_valid = true;
                        //error_log("  MATCH: Found URL is valid variation of base URL");
                        break;
                    } else {
                        //error_log("  NOT A MATCH: Found URL extends path beyond valid URL (remainder: " . $remainder . ")");
                    }
                }
                // Also check the reverse (in case valid URL has query params)
                if (strpos($valid_url, $normalized_found) === 0) {
                    $is_valid = true;
                    //error_log("  MATCH: Valid URL starts with found URL");
                    break;
                }
            }
            
            if (!$is_valid) {
                //error_log("NO MATCH FOUND - URL should be removed");
            }
        }
        
        // If URL is not valid, remove it from the response
        if (!$is_valid) {
            // Log the removal for debugging
            //error_log("MxChat: Removed hallucinated URL: " . $found_url);
            //error_log("MxChat: Valid URLs were: " . implode(', ', array_slice($normalized_valid_urls, 0, 5)));
            
            $removed_count++;
            
            // Check if URL is part of a markdown link: [text](url)
            $markdown_pattern = '/\[([^\]]+)\]\(' . preg_quote($found_url, '/') . '\)/';
            if (preg_match($markdown_pattern, $cleaned_response)) {
                //error_log("Found markdown link, removing but keeping text");
                // Remove the markdown link but keep the text
                $cleaned_response = preg_replace($markdown_pattern, '$1', $cleaned_response);
            } 
            // Check if URL is part of an HTML link: text
            else if (preg_match('/]*href=["\']' . preg_quote($found_url, '/') . '["\'][^>]*>(.*?)<\/a>/i', $cleaned_response, $link_match)) {
                //error_log("Found HTML link, removing but keeping text");
                // Remove the HTML link but keep the text
                $link_text = $link_match[1];
                $cleaned_response = preg_replace(
                    '/]*href=["\']' . preg_quote($found_url, '/') . '["\'][^>]*>.*?<\/a>/i',
                    $link_text,
                    $cleaned_response
                );
            }
            // Otherwise just remove the bare URL
            else {
                //error_log("Removing bare URL");
                $cleaned_response = str_replace($found_url, '', $cleaned_response);
            }
        }
    }
    
    // Log summary if any URLs were removed
    if ($removed_count > 0) {
        //error_log("MxChat: URL Validation Summary - Removed {$removed_count} hallucinated URL(s)");
    } else {
        //error_log("MxChat: URL Validation Summary - No URLs removed, all were valid");
    }
    
    // Clean up any double spaces or awkward punctuation left behind
    // IMPORTANT: Only collapse horizontal whitespace (spaces/tabs), preserve newlines for markdown formatting
    $cleaned_response = preg_replace('/[^\S\n]+/', ' ', $cleaned_response);  // Collapse spaces/tabs but NOT newlines
    $cleaned_response = preg_replace('/[^\S\n]+([.,;:!?])/', '$1', $cleaned_response);  // Same for punctuation cleanup
    
    //error_log("Final cleaned response: " . $cleaned_response);
    
    return trim($cleaned_response);
}

/**
 * AJAX handler to get current chat mode for a session
 */
public function mxchat_get_current_chat_mode() {
    // Verify nonce for security
    if (!isset($_POST['nonce']) || !MxChat_Integrator::mxchat_verify_chat_send_nonce($_POST['nonce'])) {
        wp_send_json_error(['message' => 'Invalid nonce']);
        wp_die();
    }
    
    $session_id = isset($_POST['session_id']) ? sanitize_text_field($_POST['session_id']) : '';
    
    if (empty($session_id)) {
        wp_send_json_error(['message' => 'Session ID missing']);
        wp_die();
    }
    
    // Get the current chat mode for this session
    $chat_mode = get_option("mxchat_mode_{$session_id}", 'ai');
    
    wp_send_json_success([
        'chat_mode' => $chat_mode
    ]);
    wp_die();
}



}
?>