<?php
/**
 * Analytics Manager Class
 *
 * Coordinates Google API integrations for SEO analytics data collection,
 * processing, and AI-powered insights generation. Manages Google Analytics,
 * Search Console, and PageSpeed data with intelligent caching and rate limiting.
 *
 * @package ThinkRank
 * @subpackage SEO
 * @since 1.0.0
 */

declare(strict_types=1);

namespace ThinkRank\SEO;

use ThinkRank\Core\Settings_Manager;
use ThinkRank\Integrations\Google_Analytics_Client;
use ThinkRank\Integrations\Google_Search_Console_Client;
use ThinkRank\Integrations\Google_PageSpeed_Client;

// Prevent direct access
if (!defined('ABSPATH')) {
    exit;
}

/**
 * Analytics Manager Class
 *
 * Single Responsibility: Coordinate Google API data collection and processing
 * Following ThinkRank manager patterns from AI_Manager and Performance_Monitoring_Manager
 *
 * @since 1.0.0
 */
class Analytics_Manager {

    /**
     * Settings Manager instance
     *
     * @var Settings_Manager
     */
    private Settings_Manager $settings_manager;

    /**
     * Google Analytics client
     *
     * @var Google_Analytics_Client|null
     */
    private ?Google_Analytics_Client $analytics_client = null;

    /**
     * Google Search Console client
     *
     * @var Google_Search_Console_Client|null
     */
    private ?Google_Search_Console_Client $search_console_client = null;

    /**
     * Google PageSpeed client
     *
     * @var Google_PageSpeed_Client|null
     */
    private ?Google_PageSpeed_Client $pagespeed_client = null;

    /**
     * Cache duration in seconds
     *
     * @var int
     */
    private int $cache_duration;

    /**
     * Constructor
     *
     * @param Settings_Manager|null $settings_manager Settings manager instance
     */
    public function __construct(?Settings_Manager $settings_manager = null) {
        $this->settings_manager = $settings_manager ?? new Settings_Manager();
        $this->cache_duration = (int) $this->get_setting('cache_duration', 3600);

        // Clear any existing cached insights to ensure new logic takes effect
        $this->clear_insights_cache();
    }

    /**
     * Initialize Analytics Manager
     * Following ThinkRank init patterns
     *
     * @return void
     */
    public function init(): void {
        // Initialize Google API clients
        add_action('init', [$this, 'initialize_clients']);

        // Schedule cache cleanup
        add_action('thinkrank_daily_cleanup', [$this, 'cleanup_cache']);
    }

    /**
     * Initialize Google API clients
     * Following AI_Manager client initialization pattern
     *
     * @return void
     */
    public function initialize_clients(): void {
        try {
            // Initialize Google Analytics client
            $ga_api_key = $this->get_setting('google_analytics_api_key');
            $ga_property_id = $this->get_setting('google_analytics_property_id');
            
            if (!empty($ga_api_key) && !empty($ga_property_id)) {
                $timeout = (int) $this->get_setting('api_timeout', 30);
                $this->analytics_client = new Google_Analytics_Client($ga_api_key, $ga_property_id, $timeout);
            }

            // Initialize Search Console client
            $gsc_api_key = $this->get_setting('google_search_console_api_key');
            
            if (!empty($gsc_api_key)) {
                $timeout = (int) $this->get_setting('api_timeout', 30);
                $this->search_console_client = new Google_Search_Console_Client($gsc_api_key, $timeout);
            }

            // Initialize PageSpeed client
            $ps_api_key = $this->get_setting('google_pagespeed_api_key');
            
            if (!empty($ps_api_key)) {
                $timeout = (int) $this->get_setting('api_timeout', 30);
                $this->pagespeed_client = new Google_PageSpeed_Client($ps_api_key, $timeout);
            }

        } catch (\Exception $e) {
            // Client initialization failed, will be handled later
        }
    }

    /**
     * Test all Google API connections
     * Following ThinkRank test_connection patterns
     *
     * @return array Connection test results
     */
    public function test_connections(): array {
        $results = [
            'google_analytics' => ['status' => 'not_configured'],
            'search_console' => ['status' => 'not_configured'],
            'pagespeed' => ['status' => 'not_configured']
        ];

        // Test Google Analytics connection
        if ($this->analytics_client) {
            try {
                $test_result = $this->analytics_client->test_connection();
                $results['google_analytics'] = [
                    'status' => $test_result['success'] ? 'connected' : 'error',
                    'message' => $test_result['message'],
                    'details' => $test_result
                ];
            } catch (\Exception $e) {
                $results['google_analytics'] = [
                    'status' => 'error',
                    'message' => $e->getMessage()
                ];
            }
        }

        // Test Search Console connection
        if ($this->search_console_client) {
            try {
                $test_result = $this->search_console_client->test_connection();
                $results['search_console'] = [
                    'status' => $test_result['success'] ? 'connected' : 'error',
                    'message' => $test_result['message'],
                    'details' => $test_result
                ];
            } catch (\Exception $e) {
                $results['search_console'] = [
                    'status' => 'error',
                    'message' => $e->getMessage()
                ];
            }
        }

        // Test PageSpeed connection
        if ($this->pagespeed_client) {
            try {
                $test_result = $this->pagespeed_client->test_connection();
                $results['pagespeed'] = [
                    'status' => $test_result['success'] ? 'connected' : 'error',
                    'message' => $test_result['message'],
                    'details' => $test_result
                ];
            } catch (\Exception $e) {
                $results['pagespeed'] = [
                    'status' => 'error',
                    'message' => $e->getMessage()
                ];
            }
        }

        return $results;
    }

    /**
     * Get analytics dashboard data
     * Combines data from all Google APIs with caching
     *
     * @param string $date_range Date range for data
     * @return array Dashboard data
     */
    public function get_dashboard_data(string $date_range = '30d'): array {
        $cache_key = "analytics_dashboard_{$date_range}";
        $cached_data = get_transient($cache_key);

        if ($cached_data !== false) {
            return $cached_data;
        }

        $dashboard_data = [
            'traffic' => [],
            'search_performance' => [],
            'core_web_vitals' => [],
            'last_updated' => current_time('mysql'),
            'date_range' => $date_range
        ];

        try {
            // Get Google Analytics traffic data
            if ($this->analytics_client) {
                $dashboard_data['traffic'] = $this->analytics_client->get_traffic_data($date_range);
                $dashboard_data['organic_traffic'] = $this->analytics_client->get_organic_traffic($date_range);
                $dashboard_data['top_pages'] = $this->analytics_client->get_top_pages(10, $date_range);
            }

            // Get Search Console data
            if ($this->search_console_client) {
                $site_url = $this->get_setting('search_console_property', get_site_url());
                $dashboard_data['search_performance'] = $this->search_console_client->get_search_performance($site_url, $date_range);
                $dashboard_data['top_queries'] = $this->search_console_client->get_top_queries($site_url, 10);
                $dashboard_data['page_performance'] = $this->search_console_client->get_page_performance($site_url, $date_range, 10);
            }

            // Get Core Web Vitals data
            if ($this->pagespeed_client) {
                $site_url = get_site_url();
                $dashboard_data['core_web_vitals'] = $this->pagespeed_client->get_core_web_vitals($site_url);
            }

        } catch (\Exception $e) {
            $dashboard_data['error'] = $e->getMessage();
        }

        // Cache the results
        set_transient($cache_key, $dashboard_data, $this->cache_duration);

        return $dashboard_data;
    }

    /**
     * Get SEO opportunities using Search Console data
     *
     * @param string $date_range Date range for analysis
     * @return array SEO opportunities
     */
    public function get_seo_opportunities(string $date_range = '30d'): array {
        $cache_key = "seo_opportunities_{$date_range}";
        $cached_data = get_transient($cache_key);

        if ($cached_data !== false) {
            return $cached_data;
        }

        $opportunities = [
            'keyword_opportunities' => [],
            'page_opportunities' => [],
            'device_insights' => [],
            'last_updated' => current_time('mysql')
        ];

        try {
            if ($this->search_console_client) {
                $site_url = $this->get_setting('search_console_property', get_site_url());
                
                // Get keyword opportunities
                $opportunities['keyword_opportunities'] = $this->search_console_client->get_keyword_opportunities($site_url, $date_range);
                
                // Get device performance insights
                $opportunities['device_insights'] = $this->search_console_client->get_device_performance($site_url, $date_range);
                
                // Get search appearance data
                $opportunities['search_appearance'] = $this->search_console_client->get_search_appearance($site_url, $date_range);
            }

        } catch (\Exception $e) {
            $opportunities['error'] = $e->getMessage();
        }

        // Cache the results
        set_transient($cache_key, $opportunities, $this->cache_duration);

        return $opportunities;
    }

    /**
     * Get setting value from integrations category
     * Following ThinkRank settings patterns
     *
     * @param string $key Setting key
     * @param mixed $default Default value
     * @return mixed Setting value
     */
    private function get_setting(string $key, $default = '') {
        $integrations_settings = $this->settings_manager->get_settings('integrations');
        return $integrations_settings[$key] ?? $default;
    }

    /**
     * One-click setup for Google Search Console verification
     * Following ThinkRank setup patterns
     *
     * @param string $site_url Site URL to verify
     * @return array Setup results
     */
    public function setup_search_console_verification(string $site_url): array {
        try {
            if (!$this->search_console_client) {
                return [
                    'success' => false,
                    'message' => 'Search Console API key not configured'
                ];
            }

            $verification_result = $this->search_console_client->verify_site($site_url);

            if ($verification_result['success']) {
                // Update settings with verified site URL
                $this->settings_manager->update_setting('integrations', 'search_console_property', $site_url);
            }

            return $verification_result;

        } catch (\Exception $e) {
            return [
                'success' => false,
                'message' => $e->getMessage()
            ];
        }
    }

    /**
     * Get site indexing status
     *
     * @return array Indexing status data
     */
    public function get_indexing_status(): array {
        $cache_key = 'indexing_status';
        $cached_data = get_transient($cache_key);

        if ($cached_data !== false) {
            return $cached_data;
        }

        $indexing_data = [
            'status' => 'unknown',
            'last_updated' => current_time('mysql')
        ];

        try {
            if ($this->search_console_client) {
                $site_url = $this->get_setting('search_console_property', get_site_url());
                $indexing_data = $this->search_console_client->get_indexing_status($site_url);
            }

        } catch (\Exception $e) {
            $indexing_data['error'] = $e->getMessage();
        }

        // Cache for 1 hour
        set_transient($cache_key, $indexing_data, 3600);

        return $indexing_data;
    }

    /**
     * Force refresh of all cached data
     *
     * @return array Refresh results
     */
    public function refresh_data(): array {
        // Clear all analytics-related transients
        $cache_keys = [
            'analytics_dashboard_7d',
            'analytics_dashboard_30d',
            'analytics_dashboard_90d',
            'seo_opportunities_7d',
            'seo_opportunities_30d',
            'seo_opportunities_90d',
            'seo_insights_7d',
            'seo_insights_30d',
            'seo_insights_90d',
            'indexing_status'
        ];

        $cleared = 0;
        foreach ($cache_keys as $key) {
            if (delete_transient($key)) {
                $cleared++;
            }
        }

        return [
            'success' => true,
            'message' => "Cleared {$cleared} cached data entries",
            'cleared_count' => $cleared,
            'timestamp' => current_time('mysql')
        ];
    }

    /**
     * Clear insights cache specifically
     *
     * @return void
     */
    private function clear_insights_cache(): void {
        $insight_cache_keys = [
            'seo_insights_7d',
            'seo_insights_30d',
            'seo_insights_90d'
        ];

        foreach ($insight_cache_keys as $key) {
            delete_transient($key);
        }
    }

    /**
     * Get client status for debugging
     *
     * @return array Client status information
     */
    public function get_client_status(): array {
        return [
            'google_analytics' => [
                'initialized' => !is_null($this->analytics_client),
                'api_key_configured' => !empty($this->get_setting('google_analytics_api_key')),
                'property_id_configured' => !empty($this->get_setting('google_analytics_property_id'))
            ],
            'search_console' => [
                'initialized' => !is_null($this->search_console_client),
                'api_key_configured' => !empty($this->get_setting('google_search_console_api_key')),
                'site_url_configured' => !empty($this->get_setting('search_console_property'))
            ],
            'pagespeed' => [
                'initialized' => !is_null($this->pagespeed_client),
                'api_key_configured' => !empty($this->get_setting('google_pagespeed_api_key'))
            ],
            'cache_duration' => $this->cache_duration,
            'last_checked' => current_time('mysql')
        ];
    }

    /**
     * Cleanup expired cache data
     * Following ThinkRank cache cleanup patterns
     *
     * @return void
     */
    public function cleanup_cache(): void {
        // WordPress handles transient cleanup automatically
        // This method is for future custom cache cleanup if needed
    }

    // ========================================
    // SEO Intelligence Enhancement Methods
    // ========================================

    /**
     * Get intelligent dashboard data with trends and insights
     *
     * @param string $date_range Date range for analysis
     * @return array Enhanced dashboard data with intelligence
     */
    public function get_intelligent_dashboard_data(string $date_range = '30d'): array {
        // Get base dashboard data
        $dashboard_data = $this->get_dashboard_data($date_range);

        // Check if there's an error in the data
        if (isset($dashboard_data['error'])) {
            return [
                'success' => false,
                'data' => null,
                'message' => 'Failed to retrieve dashboard data: ' . $dashboard_data['error'],
                'timestamp' => current_time('mysql')
            ];
        }

        // Check if we have real data available
        if (!$this->has_real_data($dashboard_data)) {
            return [
                'success' => false,
                'data' => null,
                'message' => 'No analytics data available yet. Please ensure your Google Analytics and Search Console are properly configured and have collected data.',
                'timestamp' => current_time('mysql')
            ];
        }

        // Initialize intelligence classes
        $trend_analyzer = new SEO_Trend_Analyzer();
        $scoring_engine = new SEO_Scoring_Engine();
        $insight_generator = new SEO_Insight_Generator();

        $data = $dashboard_data;

        // Generate trend analysis
        $current_data = $data;
        $historical_data = $this->get_historical_data($date_range);

        $trends = [
            'traffic_trends' => $trend_analyzer->analyze_traffic_trends($current_data, $historical_data),
            'keyword_trends' => $trend_analyzer->analyze_keyword_trends($data['search_performance'] ?? [], $date_range),
            'content_trends' => $trend_analyzer->analyze_content_trends($data, $data['search_performance'] ?? [])
        ];

        // Calculate SEO health score
        $seo_health = $scoring_engine->calculate_seo_health_score($data, $data['search_performance'] ?? []);

        // Generate insights
        $insights = [
            'traffic_insights' => $insight_generator->generate_traffic_insights($trends['traffic_trends']),
            'keyword_insights' => $insight_generator->generate_keyword_insights($trends['keyword_trends']),
            'content_insights' => $insight_generator->generate_content_insights($trends['content_trends'])
        ];

        // Combine all intelligence data
        $enhanced_data = array_merge($data, [
            'intelligence' => [
                'trends' => $trends,
                'seo_health_score' => $seo_health,
                'insights' => $insights,
                'last_analyzed' => current_time('mysql')
            ]
        ]);

        return [
            'success' => true,
            'data' => $enhanced_data,
            'message' => 'Intelligent dashboard data retrieved successfully'
        ];
    }

    /**
     * Get intelligent SEO opportunities with prioritization
     *
     * @param string $date_range Date range for analysis
     * @return array Enhanced opportunities with intelligence
     */
    public function get_intelligent_seo_opportunities(string $date_range = '30d'): array {
        // Get base opportunities data
        $opportunities_data = $this->get_seo_opportunities($date_range);

        // Check if there's an error in the data
        if (isset($opportunities_data['error'])) {
            return [
                'success' => false,
                'data' => null,
                'message' => 'Failed to retrieve opportunities data: ' . $opportunities_data['error'],
                'timestamp' => current_time('mysql')
            ];
        }

        // Check if we have real search console data for opportunities
        $search_performance = $opportunities_data['search_performance'] ?? [];
        $has_search_data = !empty($search_performance['rows']) ||
                          ($search_performance['total_clicks'] ?? 0) > 0 ||
                          ($search_performance['total_impressions'] ?? 0) > 0;

        if (!$has_search_data) {
            return [
                'success' => false,
                'data' => null,
                'message' => 'No Search Console data available yet. Please ensure your Search Console is properly configured and has collected data.',
                'timestamp' => current_time('mysql')
            ];
        }

        // Initialize intelligence classes
        $opportunity_detector = new SEO_Opportunity_Detector();
        $scoring_engine = new SEO_Scoring_Engine();

        $data = $opportunities_data;

        // Detect intelligent opportunities
        $search_console_data = $data['search_performance'] ?? [];
        $analytics_data = $data;

        $intelligent_opportunities = [
            'quick_wins' => $opportunity_detector->detect_quick_wins($search_console_data, $analytics_data),
            'content_opportunities' => $opportunity_detector->identify_content_opportunities($search_console_data, $analytics_data),
            'keyword_opportunities' => $scoring_engine->score_keyword_opportunities($search_console_data)
        ];

        // Prioritize all opportunities
        $all_opportunities = array_merge(
            $intelligent_opportunities['quick_wins']['opportunities'] ?? [],
            $intelligent_opportunities['content_opportunities']['opportunities'] ?? [],
            $intelligent_opportunities['keyword_opportunities']['opportunities'] ?? []
        );

        $prioritized = $opportunity_detector->prioritize_opportunities($all_opportunities);
        $impact_matrix = $opportunity_detector->calculate_impact_effort_matrix($all_opportunities);

        // Enhance original data with intelligence
        $enhanced_data = array_merge($data, [
            'intelligent_opportunities' => $intelligent_opportunities,
            'prioritized_opportunities' => $prioritized,
            'impact_effort_matrix' => $impact_matrix,
            'opportunity_summary' => $this->generate_opportunity_summary($intelligent_opportunities),
            'last_analyzed' => current_time('mysql')
        ]);

        return [
            'success' => true,
            'data' => $enhanced_data,
            'message' => 'Intelligent SEO opportunities retrieved successfully'
        ];
    }

    /**
     * Get SEO performance insights
     *
     * @param string $date_range Date range for analysis
     * @return array SEO insights data
     */
    public function get_seo_insights(string $date_range = '30d'): array {
        $cache_key = "seo_insights_{$date_range}";
        $cached_data = get_transient($cache_key);

        if ($cached_data !== false) {
            return [
                'success' => true,
                'data' => $cached_data,
                'cached' => true,
                'message' => 'SEO insights retrieved from cache'
            ];
        }

        try {
            // Get dashboard data for analysis
            $dashboard_result = $this->get_intelligent_dashboard_data($date_range);

            if (!$dashboard_result['success']) {
                return $dashboard_result;
            }

            $dashboard_data = $dashboard_result['data'];
            $intelligence = $dashboard_data['intelligence'] ?? [];

            // Initialize insight generator
            $insight_generator = new SEO_Insight_Generator();

            // Collect all insights
            $all_insights = [];

            if (!empty($intelligence['insights']['traffic_insights']['insights'])) {
                $all_insights = array_merge($all_insights, $intelligence['insights']['traffic_insights']['insights']);
            }

            if (!empty($intelligence['insights']['keyword_insights']['insights'])) {
                $all_insights = array_merge($all_insights, $intelligence['insights']['keyword_insights']['insights']);
            }

            if (!empty($intelligence['insights']['content_insights']['insights'])) {
                $all_insights = array_merge($all_insights, $intelligence['insights']['content_insights']['insights']);
            }

            // Format and prioritize insights
            $formatted_insights = $insight_generator->format_insights_for_display($all_insights);
            $prioritized_insights = $insight_generator->prioritize_insights_by_impact($formatted_insights);

            $insights_data = [
                'insights' => $prioritized_insights['prioritized_insights'],
                'summary' => [
                    'total_insights' => count($formatted_insights),
                    'high_impact_count' => $prioritized_insights['high_impact_count'],
                    'action_required_count' => $prioritized_insights['action_required_count']
                ],
                'seo_health_score' => $intelligence['seo_health_score'] ?? null,
                'generated_at' => current_time('mysql')
            ];

            // Cache the results
            set_transient($cache_key, $insights_data, $this->cache_duration);

            return [
                'success' => true,
                'data' => $insights_data,
                'cached' => false,
                'message' => 'SEO insights generated successfully'
            ];

        } catch (Exception $e) {
            return [
                'success' => false,
                'error' => 'Failed to generate SEO insights: ' . $e->getMessage(),
                'data' => null
            ];
        }
    }

    /**
     * Check if real analytics data is available
     *
     * @param array $dashboard_data Dashboard data to check
     * @return bool True if real data is available
     */
    private function has_real_data(array $dashboard_data): bool {
        // Check if we have meaningful traffic data
        $traffic = $dashboard_data['traffic'] ?? [];
        $search_performance = $dashboard_data['search_performance'] ?? [];

        $has_traffic = !empty($traffic) && (
            ($traffic['sessions'] ?? 0) > 0 ||
            ($traffic['pageviews'] ?? 0) > 0 ||
            ($traffic['active_users'] ?? 0) > 0
        );

        $has_search_data = !empty($search_performance) && (
            !empty($search_performance['rows']) ||
            ($search_performance['total_clicks'] ?? 0) > 0 ||
            ($search_performance['total_impressions'] ?? 0) > 0
        );

        return $has_traffic || $has_search_data;
    }

    /**
     * Get historical data for trend comparison
     *
     * @param string $current_range Current date range
     * @return array Historical data
     */
    private function get_historical_data(string $current_range): array {
        // Calculate previous period based on current range
        $previous_range = $this->calculate_previous_period($current_range);

        // Try to get actual historical data from previous period
        $historical_data = $this->get_dashboard_data($previous_range);

        // Return the actual historical data (may be empty if no real data available)
        return [
            'sessions' => $historical_data['traffic']['sessions'] ?? 0,
            'pageviews' => $historical_data['traffic']['pageviews'] ?? 0,
            'organic_traffic' => $historical_data['organic_traffic'] ?? ['organic_traffic' => ['sessions' => 0]],
            'bounce_rate' => $historical_data['traffic']['bounce_rate'] ?? 0,
            'avg_session_duration' => $historical_data['traffic']['avg_session_duration'] ?? 0
        ];
    }

    /**
     * Calculate previous period for comparison
     *
     * @param string $current_range Current range
     * @return string Previous period range
     */
    private function calculate_previous_period(string $current_range): string {
        // Simple mapping for now - could be enhanced with actual date calculations
        $period_mapping = [
            '7d' => '14d',
            '30d' => '60d',
            '90d' => '180d'
        ];

        return $period_mapping[$current_range] ?? '60d';
    }

    /**
     * Generate opportunity summary
     *
     * @param array $opportunities All opportunities
     * @return array Opportunity summary
     */
    private function generate_opportunity_summary(array $opportunities): array {
        $quick_wins_count = count($opportunities['quick_wins']['opportunities'] ?? []);
        $content_opportunities_count = count($opportunities['content_opportunities']['opportunities'] ?? []);
        $keyword_opportunities_count = count($opportunities['keyword_opportunities']['opportunities'] ?? []);

        $total_opportunities = $quick_wins_count + $content_opportunities_count + $keyword_opportunities_count;

        $potential_clicks = 0;
        if (!empty($opportunities['quick_wins']['potential_additional_clicks'])) {
            $potential_clicks = $opportunities['quick_wins']['potential_additional_clicks'];
        }

        return [
            'total_opportunities' => $total_opportunities,
            'quick_wins_count' => $quick_wins_count,
            'content_opportunities_count' => $content_opportunities_count,
            'keyword_opportunities_count' => $keyword_opportunities_count,
            'potential_additional_clicks' => $potential_clicks,
            'priority_recommendation' => $quick_wins_count > 0 ?
                'Focus on quick wins first for immediate impact' :
                'Focus on content optimization for long-term growth'
        ];
    }

    /**
     * Clear intelligence cache
     *
     * @return array Clear result
     */
    public function clear_intelligence_cache(): array {
        $intelligence_cache_keys = [
            'seo_insights_7d',
            'seo_insights_30d',
            'seo_insights_90d',
            'intelligent_dashboard_7d',
            'intelligent_dashboard_30d',
            'intelligent_dashboard_90d',
            'intelligent_opportunities_7d',
            'intelligent_opportunities_30d',
            'intelligent_opportunities_90d'
        ];

        $cleared = 0;
        foreach ($intelligence_cache_keys as $key) {
            if (delete_transient($key)) {
                $cleared++;
            }
        }

        return [
            'success' => true,
            'message' => "Cleared {$cleared} intelligence cache entries",
            'cleared_count' => $cleared,
            'timestamp' => current_time('mysql')
        ];
    }
}