<?php
if (!defined('ABSPATH')) {
    exit; // Exit if accessed directly
}

class MxChat_Utils {

    /**
     * Submit or update content (and its embedding) in the database.
     *
     * If the source_url already exists, update that row.
     * Otherwise, insert a new row.
     *
     * @param string $content    The content to be embedded.
     * @param string $source_url The source URL of the content.
     * @param string $api_key    The API key used for generating embeddings.
     */
    public static function submit_content_to_db($content, $source_url, $api_key) {
        global $wpdb;
        $table_name = $wpdb->prefix . 'mxchat_system_prompt_content';

        // Sanitize the source URL
        $source_url = esc_url_raw($source_url);

        // Generate the embedding using the API key
        $embedding_vector = self::generate_embedding($content, $api_key);

        if (is_array($embedding_vector)) {
            $embedding_vector_serialized = maybe_serialize($embedding_vector);

            // Check if a row already exists for this URL
            $existing_id = $wpdb->get_var(
                $wpdb->prepare(
                    "SELECT id FROM {$table_name} WHERE source_url = %s LIMIT 1",
                    $source_url
                )
            );

            if ($existing_id) {
                // Update the existing row
                $wpdb->update(
                    $table_name,
                    array(
                        'article_content'  => $content,
                        'embedding_vector' => $embedding_vector_serialized,
                        'timestamp'        => current_time('mysql'),  // Remove if your table doesn't have a timestamp column
                    ),
                    array('id' => $existing_id),
                    array('%s','%s','%s'),
                    array('%d')
                );
            } else {
                // Insert a new row
                $wpdb->insert(
                    $table_name,
                    array(
                        'article_content'  => $content,
                        'embedding_vector' => $embedding_vector_serialized,
                        'source_url'       => $source_url,
                        'timestamp'        => current_time('mysql'), // Remove if your table doesn't have a timestamp column
                    ),
                    array('%s','%s','%s','%s')
                );
            }
        } else {
            // If embedding generation failed, you could log or handle it here
            // error_log('Embedding generation failed for content from ' . $source_url);
        }
    }

    /**
     * Generate an embedding for the given text using the specified API key.
     *
     * @param string $text    The text to be embedded.
     * @param string $api_key The API key used for generating embeddings.
     * @return array|null     The embedding vector or null on failure.
     */
    private static function generate_embedding($text, $api_key) {
        $endpoint = 'https://api.openai.com/v1/embeddings';

        $body = wp_json_encode([
            'input' => $text,
            'model' => 'text-embedding-ada-002'
        ]);

        $args = [
            'body'        => $body,
            'headers'     => [
                'Content-Type'  => 'application/json',
                'Authorization' => 'Bearer ' . $api_key,
            ],
            'timeout'     => 60,
            'redirection' => 5,
            'blocking'    => true,
            'httpversion' => '1.0',
            'sslverify'   => true,
        ];

        $response = wp_remote_post($endpoint, $args);

        if (is_wp_error($response)) {
            // error_log('Error generating embedding: ' . $response->get_error_message());
            return null;
        }

        $response_body = json_decode(wp_remote_retrieve_body($response), true);

        if (isset($response_body['data'][0]['embedding']) && is_array($response_body['data'][0]['embedding'])) {
            return $response_body['data'][0]['embedding'];
        } else {
            // error_log('Invalid response received from embedding API.');
            return null;
        }
    }
}