<?php
/**
 * User Queue Manager
 * 
 * Handles user-specific queues, extensions, and hold queues
 */
class TWP_User_Queue_Manager {
    
    /**
     * Create personal and hold queues for a user
     * 
     * @param int $user_id WordPress user ID
     * @param string $extension User's extension number
     * @return array Array with queue IDs and extension info
     */
    public static function create_user_queues($user_id, $extension = null) {
        global $wpdb;
        
        $user = get_user_by('id', $user_id);
        if (!$user) {
            return array('success' => false, 'error' => 'User not found');
        }
        
        // Generate extension if not provided
        if (!$extension) {
            $extension = self::generate_unique_extension();
        }
        
        // Check if extension already exists
        $existing = $wpdb->get_var($wpdb->prepare(
            "SELECT extension FROM {$wpdb->prefix}twp_user_extensions WHERE extension = %s",
            $extension
        ));
        
        if ($existing) {
            return array('success' => false, 'error' => 'Extension already exists');
        }
        
        // Create personal queue
        $personal_queue_name = sprintf('%s (%s)', $user->display_name, $extension);
        $personal_queue_id = $wpdb->insert(
            $wpdb->prefix . 'twp_call_queues',
            array(
                'queue_name' => $personal_queue_name,
                'queue_type' => 'personal',
                'user_id' => $user_id,
                'extension' => $extension,
                'max_size' => 10,
                'timeout_seconds' => 300, // 5 minutes for logged-in users
                'voicemail_prompt' => sprintf('You have reached %s. Please leave a message after the tone.', $user->display_name),
                'is_hold_queue' => 0
            ),
            array('%s', '%s', '%d', '%s', '%d', '%d', '%s', '%d')
        );
        
        if (!$personal_queue_id) {
            return array('success' => false, 'error' => 'Failed to create personal queue');
        }
        
        $personal_queue_id = $wpdb->insert_id;
        
        // Create hold queue
        $hold_queue_name = sprintf('Hold - %s', $user->display_name);
        $hold_queue_id = $wpdb->insert(
            $wpdb->prefix . 'twp_call_queues',
            array(
                'queue_name' => $hold_queue_name,
                'queue_type' => 'hold',
                'user_id' => $user_id,
                'extension' => null, // Hold queues don't have extensions
                'max_size' => 5,
                'timeout_seconds' => 0, // No timeout for hold queues
                'tts_message' => 'Your call is on hold. Please wait.',
                'is_hold_queue' => 1
            ),
            array('%s', '%s', '%d', '%s', '%d', '%d', '%s', '%d')
        );
        
        if (!$hold_queue_id) {
            // Rollback personal queue creation
            $wpdb->delete($wpdb->prefix . 'twp_call_queues', array('id' => $personal_queue_id));
            return array('success' => false, 'error' => 'Failed to create hold queue');
        }
        
        $hold_queue_id = $wpdb->insert_id;
        
        // Create user extension record
        $extension_result = $wpdb->insert(
            $wpdb->prefix . 'twp_user_extensions',
            array(
                'user_id' => $user_id,
                'extension' => $extension,
                'personal_queue_id' => $personal_queue_id,
                'hold_queue_id' => $hold_queue_id
            ),
            array('%d', '%s', '%d', '%d')
        );
        
        if (!$extension_result) {
            // Rollback queue creations
            $wpdb->delete($wpdb->prefix . 'twp_call_queues', array('id' => $personal_queue_id));
            $wpdb->delete($wpdb->prefix . 'twp_call_queues', array('id' => $hold_queue_id));
            return array('success' => false, 'error' => 'Failed to create extension record');
        }
        
        // Auto-assign user to their personal queue
        $wpdb->insert(
            $wpdb->prefix . 'twp_queue_assignments',
            array(
                'user_id' => $user_id,
                'queue_id' => $personal_queue_id,
                'is_primary' => 1
            ),
            array('%d', '%d', '%d')
        );
        
        // Auto-assign user to their hold queue
        $wpdb->insert(
            $wpdb->prefix . 'twp_queue_assignments',
            array(
                'user_id' => $user_id,
                'queue_id' => $hold_queue_id,
                'is_primary' => 0
            ),
            array('%d', '%d', '%d')
        );
        
        return array(
            'success' => true,
            'extension' => $extension,
            'personal_queue_id' => $personal_queue_id,
            'hold_queue_id' => $hold_queue_id
        );
    }
    
    /**
     * Generate a unique extension number
     * 
     * @return string Extension number (3-4 digits)
     */
    private static function generate_unique_extension() {
        global $wpdb;
        
        // Start with 100 for 3-digit extensions
        $start = 100;
        $max_attempts = 900; // Up to 999
        
        for ($i = 0; $i < $max_attempts; $i++) {
            $extension = (string)($start + $i);
            
            $exists = $wpdb->get_var($wpdb->prepare(
                "SELECT extension FROM {$wpdb->prefix}twp_user_extensions WHERE extension = %s",
                $extension
            ));
            
            if (!$exists) {
                return $extension;
            }
        }
        
        // If all 3-digit extensions are taken, try 4-digit starting at 1000
        $start = 1000;
        $max_attempts = 9000; // Up to 9999
        
        for ($i = 0; $i < $max_attempts; $i++) {
            $extension = (string)($start + $i);
            
            $exists = $wpdb->get_var($wpdb->prepare(
                "SELECT extension FROM {$wpdb->prefix}twp_user_extensions WHERE extension = %s",
                $extension
            ));
            
            if (!$exists) {
                return $extension;
            }
        }
        
        return null; // All extensions taken (unlikely)
    }
    
    /**
     * Get user's extension and queue information
     * 
     * @param int $user_id WordPress user ID
     * @return array|null Extension and queue data
     */
    public static function get_user_extension_data($user_id) {
        global $wpdb;
        
        $data = $wpdb->get_row($wpdb->prepare(
            "SELECT * FROM {$wpdb->prefix}twp_user_extensions WHERE user_id = %d",
            $user_id
        ), ARRAY_A);
        
        return $data;
    }
    
    /**
     * Get user by extension
     * 
     * @param string $extension Extension number
     * @return int|null User ID
     */
    public static function get_user_by_extension($extension) {
        global $wpdb;
        
        $user_id = $wpdb->get_var($wpdb->prepare(
            "SELECT user_id FROM {$wpdb->prefix}twp_user_extensions WHERE extension = %s",
            $extension
        ));
        
        return $user_id ? intval($user_id) : null;
    }
    
    /**
     * Get all queues assigned to a user
     * 
     * @param int $user_id WordPress user ID
     * @return array Array of queue data
     */
    public static function get_user_assigned_queues($user_id) {
        global $wpdb;
        
        $query = $wpdb->prepare("
            SELECT q.*, qa.is_primary,
                   (SELECT COUNT(*) FROM {$wpdb->prefix}twp_queued_calls qc 
                    WHERE qc.queue_id = q.id AND qc.status = 'waiting') as waiting_calls
            FROM {$wpdb->prefix}twp_call_queues q
            INNER JOIN {$wpdb->prefix}twp_queue_assignments qa ON q.id = qa.queue_id
            WHERE qa.user_id = %d
            ORDER BY qa.is_primary DESC, q.queue_name ASC
        ", $user_id);
        
        $queues = $wpdb->get_results($query, ARRAY_A);
        
        return $queues;
    }
    
    /**
     * Update queue timeout based on user login status
     * 
     * @param int $user_id WordPress user ID
     * @param bool $is_logged_in Whether user is logged in
     */
    public static function update_queue_timeout_for_login($user_id, $is_logged_in) {
        global $wpdb;
        
        // Get user's personal queue
        $extension_data = self::get_user_extension_data($user_id);
        
        if (!$extension_data || !$extension_data['personal_queue_id']) {
            return;
        }
        
        // Update timeout: 5 minutes if logged in, 0 (immediate voicemail) if logged out
        $timeout = $is_logged_in ? 300 : 0;
        
        $wpdb->update(
            $wpdb->prefix . 'twp_call_queues',
            array('timeout_seconds' => $timeout),
            array('id' => $extension_data['personal_queue_id']),
            array('%d'),
            array('%d')
        );
    }
    
    /**
     * Transfer call to user's hold queue
     * 
     * @param int $user_id WordPress user ID
     * @param string $call_sid Call SID to transfer
     * @return array Result array
     */
    public static function transfer_to_hold_queue($user_id, $call_sid) {
        global $wpdb;
        
        // Get user's hold queue
        $extension_data = self::get_user_extension_data($user_id);
        
        if (!$extension_data || !$extension_data['hold_queue_id']) {
            return array('success' => false, 'error' => 'Hold queue not found for user');
        }
        
        // Check if call exists in any queue
        $current_queue = $wpdb->get_row($wpdb->prepare(
            "SELECT * FROM {$wpdb->prefix}twp_queued_calls WHERE call_sid = %s AND status = 'waiting'",
            $call_sid
        ), ARRAY_A);
        
        if (!$current_queue) {
            return array('success' => false, 'error' => 'Call not found in queue');
        }
        
        // Move call to hold queue
        $result = $wpdb->update(
            $wpdb->prefix . 'twp_queued_calls',
            array(
                'queue_id' => $extension_data['hold_queue_id'],
                'position' => 1 // Reset position in hold queue
            ),
            array('id' => $current_queue['id']),
            array('%d', '%d'),
            array('%d')
        );
        
        if ($result === false) {
            return array('success' => false, 'error' => 'Failed to transfer to hold queue');
        }
        
        return array(
            'success' => true,
            'hold_queue_id' => $extension_data['hold_queue_id']
        );
    }
    
    /**
     * Transfer call from hold queue back to original or specified queue
     * 
     * @param int $user_id WordPress user ID
     * @param string $call_sid Call SID to transfer
     * @param int $target_queue_id Optional target queue ID
     * @return array Result array
     */
    public static function resume_from_hold($user_id, $call_sid, $target_queue_id = null) {
        global $wpdb;
        
        // Get user's hold queue
        $extension_data = self::get_user_extension_data($user_id);
        
        if (!$extension_data || !$extension_data['hold_queue_id']) {
            return array('success' => false, 'error' => 'Hold queue not found for user');
        }
        
        // Check if call is in hold queue
        $held_call = $wpdb->get_row($wpdb->prepare(
            "SELECT * FROM {$wpdb->prefix}twp_queued_calls 
             WHERE call_sid = %s AND queue_id = %d AND status = 'waiting'",
            $call_sid,
            $extension_data['hold_queue_id']
        ), ARRAY_A);
        
        if (!$held_call) {
            return array('success' => false, 'error' => 'Call not found in hold queue');
        }
        
        // Determine target queue
        if (!$target_queue_id) {
            // Default to user's personal queue
            $target_queue_id = $extension_data['personal_queue_id'];
        }
        
        // Get next position in target queue
        $next_position = $wpdb->get_var($wpdb->prepare(
            "SELECT COALESCE(MAX(position), 0) + 1 FROM {$wpdb->prefix}twp_queued_calls 
             WHERE queue_id = %d AND status = 'waiting'",
            $target_queue_id
        ));
        
        // Move call to target queue
        $result = $wpdb->update(
            $wpdb->prefix . 'twp_queued_calls',
            array(
                'queue_id' => $target_queue_id,
                'position' => $next_position
            ),
            array('id' => $held_call['id']),
            array('%d', '%d'),
            array('%d')
        );
        
        if ($result === false) {
            return array('success' => false, 'error' => 'Failed to resume from hold');
        }
        
        return array(
            'success' => true,
            'target_queue_id' => $target_queue_id,
            'position' => $next_position
        );
    }
    
    /**
     * Initialize user queues for all existing users
     * This should be called during plugin activation or upgrade
     */
    public static function initialize_all_user_queues() {
        $users = get_users(array(
            'fields' => 'ID',
            'meta_key' => 'twp_phone_number',
            'meta_compare' => 'EXISTS'
        ));
        
        $results = array(
            'success' => 0,
            'failed' => 0,
            'skipped' => 0
        );
        
        foreach ($users as $user_id) {
            // Check if user already has queues
            $existing = self::get_user_extension_data($user_id);
            
            if ($existing) {
                $results['skipped']++;
                continue;
            }
            
            $result = self::create_user_queues($user_id);
            
            if ($result['success']) {
                $results['success']++;
            } else {
                $results['failed']++;
                error_log('TWP: Failed to create queues for user ' . $user_id . ': ' . $result['error']);
            }
        }
        
        return $results;
    }
}