<?php
/**
 * Active Viewer Model
 * Handles real-time viewer tracking and activity monitoring
 */

class ActiveViewerModel
{
    private $db;

    public function __construct()
    {
        $this->db = Database::getInstance();
    }

    /**
     * Update or create active viewer record
     */
    public function heartbeat($userId, $data = [])
    {
        $sql = "INSERT OR REPLACE INTO active_viewers
                (user_id, nickname, ip_address, session_id, is_admin)
                VALUES (?, ?, ?, ?, ?)";

        $params = [
            $userId,
            $data['nickname'] ?? 'Anonymous',
            $data['ip_address'] ?? Security::getClientIP(),
            $data['session_id'] ?? session_id(),
            $data['is_admin'] ?? false
        ];

        return $this->db->insert($sql, $params);
    }

    /**
     * Get count of active viewers (seen within last X seconds)
     */
    public function getActiveCount($thresholdSeconds = 30)
    {
        return $this->db->fetchColumn(
            "SELECT COUNT(*) FROM active_viewers WHERE last_seen >= datetime('now', '-{$thresholdSeconds} seconds')"
        );
    }

    /**
     * Get list of active viewers with details
     */
    public function getActiveViewers($thresholdSeconds = 30)
    {
        return $this->db->fetchAll(
            "SELECT * FROM active_viewers WHERE last_seen >= datetime('now', '-{$thresholdSeconds} seconds') ORDER BY last_seen DESC"
        );
    }

    /**
     * Clean up inactive viewers
     */
    public function cleanupInactive($thresholdSeconds = 60)
    {
        return $this->db->delete(
            "DELETE FROM active_viewers WHERE last_seen < datetime('now', '-{$thresholdSeconds} seconds')"
        );
    }

    /**
     * Update specific viewer's last seen time
     */
    public function updateLastSeen($userId)
    {
        return $this->db->update(
            "UPDATE active_viewers SET last_seen = ? WHERE user_id = ?",
            [date('Y-m-d H:i:s'), $userId]
        );
    }

    /**
     * Remove viewer from active list
     */
    public function removeViewer($userId)
    {
        return $this->db->delete(
            "DELETE FROM active_viewers WHERE user_id = ?",
            [$userId]
        );
    }

    /**
     * Get viewer by user ID
     */
    public function getViewer($userId)
    {
        return $this->db->fetch(
            "SELECT * FROM active_viewers WHERE user_id = ?",
            [$userId]
        );
    }

    /**
     * Bulk update multiple viewers (for mass heartbeat handling)
     */
    public function bulkHeartbeat($viewersData)
    {
        $this->db->beginTransaction();

        try {
            foreach ($viewersData as $viewerData) {
                $userId = $viewerData['user_id'] ?? '';
                if (!empty($userId)) {
                    $this->heartbeat($userId, $viewerData);
                }
            }

            $this->db->commit();
            return true;
        } catch (Exception $e) {
            $this->db->rollback();
            error_log("Bulk heartbeat failed: " . $e->getMessage());
            return false;
        }
    }

    /**
     * Get viewer activity statistics
     */
    public function getActivityStats()
    {
        $stats = [];

        // Current active count
        $stats['currently_active'] = $this->db->fetchColumn(
            "SELECT COUNT(*) FROM active_viewers WHERE last_seen >= datetime('now', '-30 seconds')"
        );

        // Peak today
        $stats['peak_today'] = $this->db->fetchColumn(
            "SELECT COUNT(*) FROM active_viewers WHERE DATE(last_seen) = DATE('now')"
        );

        // Viewer types
        $stats['admin_count'] = $this->db->fetchColumn(
            "SELECT COUNT(*) FROM active_viewers WHERE is_admin = 1 AND last_seen >= datetime('now', '-30 seconds')"
        );

        // Recent joiners (joined in last 5 minutes)
        $stats['recent_joiners'] = $this->db->fetchColumn(
            "SELECT COUNT(*) FROM active_viewers WHERE last_seen >= datetime('now', '-5 minutes')"
        );

        // Top user agents
        $stats['user_agents'] = $this->db->fetchAll(
            "SELECT user_agent, COUNT(*) as count FROM active_viewers
             WHERE last_seen >= datetime('now', '-1 hour')
             GROUP BY user_agent
             ORDER BY count DESC LIMIT 5"
        );

        return $stats;
    }

    /**
     * Migrate old file-based viewer data if exists
     */
    public function migrateFromFileIfNeeded()
    {
        $oldViewersFile = __DIR__ . '/../active_viewers.json';

        if (!file_exists($oldViewersFile)) {
            return;
        }

        try {
            $oldData = json_decode(file_get_contents($oldViewersFile), true);

            if (is_array($oldData)) {
                $this->db->beginTransaction();

                foreach ($oldData as $viewer) {
                    if (!empty($viewer['user_id'])) {
                        $this->heartbeat($viewer['user_id'], [
                            'nickname' => $viewer['nickname'] ?? 'Anonymous',
                            'ip_address' => $viewer['ip_address'] ?? '',
                            'session_id' => $viewer['session_id'] ?? '',
                            'is_admin' => $viewer['is_admin'] ?? false
                        ]);
                    }
                }

                $this->db->commit();

                // Backup old file and remove it
                rename($oldViewersFile, $oldViewersFile . '.migrated.' . date('Y-m-d_H-i-s'));
                error_log("Migrated " . count($oldData) . " viewers from file to database");
            }
        } catch (Exception $e) {
            error_log("Migration from file failed: " . $e->getMessage());
        }
    }
}