<?php
/**
 * Call queue management class
 */
class TWP_Call_Queue {
    
    /**
     * Add call to queue
     */
    public static function add_to_queue($queue_id, $call_data) {
        global $wpdb;
        $table_name = $wpdb->prefix . 'twp_queued_calls';
        
        // Get current position in queue
        $max_position = $wpdb->get_var($wpdb->prepare(
            "SELECT MAX(position) FROM $table_name WHERE queue_id = %d AND status = 'waiting'",
            $queue_id
        ));
        
        $position = $max_position ? $max_position + 1 : 1;
        
        $result = $wpdb->insert(
            $table_name,
            array(
                'queue_id' => $queue_id,
                'call_sid' => sanitize_text_field($call_data['call_sid']),
                'from_number' => sanitize_text_field($call_data['from_number']),
                'to_number' => sanitize_text_field($call_data['to_number']),
                'position' => $position,
                'status' => 'waiting'
            ),
            array('%d', '%s', '%s', '%s', '%d', '%s')
        );
        
        return $result !== false ? $position : false;
    }
    
    /**
     * Remove call from queue
     */
    public static function remove_from_queue($call_sid) {
        global $wpdb;
        $table_name = $wpdb->prefix . 'twp_queued_calls';
        
        // Get call info before removing
        $call = $wpdb->get_row($wpdb->prepare(
            "SELECT * FROM $table_name WHERE call_sid = %s",
            $call_sid
        ));
        
        if ($call) {
            // Update status
            $wpdb->update(
                $table_name,
                array(
                    'status' => 'completed',
                    'ended_at' => current_time('mysql')
                ),
                array('call_sid' => $call_sid),
                array('%s', '%s'),
                array('%s')
            );
            
            // Reorder queue positions
            self::reorder_queue($call->queue_id);
            
            return true;
        }
        
        return false;
    }
    
    /**
     * Get next call in queue
     */
    public static function get_next_call($queue_id) {
        global $wpdb;
        $table_name = $wpdb->prefix . 'twp_queued_calls';
        
        return $wpdb->get_row($wpdb->prepare(
            "SELECT * FROM $table_name 
             WHERE queue_id = %d AND status = 'waiting' 
             ORDER BY position ASC 
             LIMIT 1",
            $queue_id
        ));
    }
    
    /**
     * Answer queued call
     */
    public static function answer_call($call_sid, $agent_number) {
        global $wpdb;
        $table_name = $wpdb->prefix . 'twp_queued_calls';
        
        // Update call status
        $wpdb->update(
            $table_name,
            array(
                'status' => 'answered',
                'answered_at' => current_time('mysql')
            ),
            array('call_sid' => $call_sid),
            array('%s', '%s'),
            array('%s')
        );
        
        // Connect call to agent
        $twilio = new TWP_Twilio_API();
        $twilio->forward_call($call_sid, $agent_number);
        
        return true;
    }
    
    /**
     * Process waiting calls
     */
    public function process_waiting_calls() {
        global $wpdb;
        $table_name = $wpdb->prefix . 'twp_queued_calls';
        $queue_table = $wpdb->prefix . 'twp_call_queues';
        
        // Get all active queues
        $queues = $wpdb->get_results("SELECT * FROM $queue_table");
        
        foreach ($queues as $queue) {
            // Check for timed out calls
            $timeout_time = date('Y-m-d H:i:s', strtotime('-' . $queue->timeout_seconds . ' seconds'));
            
            $timed_out_calls = $wpdb->get_results($wpdb->prepare(
                "SELECT * FROM $table_name 
                 WHERE queue_id = %d 
                 AND status = 'waiting' 
                 AND joined_at <= %s",
                $queue->id,
                $timeout_time
            ));
            
            foreach ($timed_out_calls as $call) {
                // Handle timeout
                $this->handle_timeout($call, $queue);
            }
            
            // Update caller positions and play position messages
            $this->update_queue_positions($queue->id);
        }
    }
    
    /**
     * Handle call timeout
     */
    private function handle_timeout($call, $queue) {
        global $wpdb;
        $table_name = $wpdb->prefix . 'twp_queued_calls';
        
        // Update status
        $wpdb->update(
            $table_name,
            array(
                'status' => 'timeout',
                'ended_at' => current_time('mysql')
            ),
            array('id' => $call->id),
            array('%s', '%s'),
            array('%d')
        );
        
        // Offer callback instead of hanging up
        $callback_twiml = TWP_Callback_Manager::create_callback_twiml($queue->id, $call->from_number);
        
        $twilio = new TWP_Twilio_API();
        $twilio->update_call($call->call_sid, array(
            'Twiml' => $callback_twiml
        ));
        
        // Reorder queue
        self::reorder_queue($queue->id);
    }
    
    /**
     * Update queue positions
     */
    private function update_queue_positions($queue_id) {
        global $wpdb;
        $table_name = $wpdb->prefix . 'twp_queued_calls';
        
        $waiting_calls = $wpdb->get_results($wpdb->prepare(
            "SELECT * FROM $table_name 
             WHERE queue_id = %d AND status = 'waiting' 
             ORDER BY position ASC",
            $queue_id
        ));
        
        foreach ($waiting_calls as $index => $call) {
            $position = $index + 1;
            
            // Update position if changed
            if ($call->position != $position) {
                $wpdb->update(
                    $table_name,
                    array('position' => $position),
                    array('id' => $call->id),
                    array('%d'),
                    array('%d')
                );
            }
            
            // Announce position every 30 seconds
            $last_announcement = get_transient('twp_queue_announce_' . $call->call_sid);
            
            if (!$last_announcement) {
                $this->announce_position($call, $position);
                set_transient('twp_queue_announce_' . $call->call_sid, true, 30);
            }
        }
    }
    
    /**
     * Announce queue position
     */
    private function announce_position($call, $position) {
        $twilio = new TWP_Twilio_API();
        $elevenlabs = new TWP_ElevenLabs_API();
        
        $message = "You are currently number $position in the queue. Please hold and an agent will be with you shortly.";
        
        // Generate TTS audio
        $audio_result = $elevenlabs->text_to_speech($message);
        
        if ($audio_result['success']) {
            // Create TwiML with audio
            $twiml = new SimpleXMLElement('<?xml version="1.0" encoding="UTF-8"?><Response></Response>');
            $play = $twiml->addChild('Play', $audio_result['file_url']);
            $play->addAttribute('loop', '0');
            
            // Add wait music
            $queue = self::get_queue($call->queue_id);
            if ($queue && $queue->wait_music_url) {
                $play_music = $twiml->addChild('Play', $queue->wait_music_url);
                $play_music->addAttribute('loop', '0');
            }
            
            $twilio->update_call($call->call_sid, array(
                'Twiml' => $twiml->asXML()
            ));
        }
    }
    
    /**
     * Reorder queue positions
     */
    private static function reorder_queue($queue_id) {
        global $wpdb;
        $table_name = $wpdb->prefix . 'twp_queued_calls';
        
        $waiting_calls = $wpdb->get_results($wpdb->prepare(
            "SELECT id FROM $table_name 
             WHERE queue_id = %d AND status = 'waiting' 
             ORDER BY position ASC",
            $queue_id
        ));
        
        foreach ($waiting_calls as $index => $call) {
            $wpdb->update(
                $table_name,
                array('position' => $index + 1),
                array('id' => $call->id),
                array('%d'),
                array('%d')
            );
        }
    }
    
    /**
     * Create queue
     */
    public static function create_queue($data) {
        global $wpdb;
        $table_name = $wpdb->prefix . 'twp_call_queues';
        
        return $wpdb->insert(
            $table_name,
            array(
                'queue_name' => sanitize_text_field($data['queue_name']),
                'max_size' => intval($data['max_size']),
                'wait_music_url' => esc_url_raw($data['wait_music_url']),
                'tts_message' => sanitize_textarea_field($data['tts_message']),
                'timeout_seconds' => intval($data['timeout_seconds'])
            ),
            array('%s', '%d', '%s', '%s', '%d')
        );
    }
    
    /**
     * Get queue
     */
    public static function get_queue($queue_id) {
        global $wpdb;
        $table_name = $wpdb->prefix . 'twp_call_queues';
        
        return $wpdb->get_row($wpdb->prepare(
            "SELECT * FROM $table_name WHERE id = %d",
            $queue_id
        ));
    }
    
    /**
     * Get all queues
     */
    public static function get_all_queues() {
        global $wpdb;
        $table_name = $wpdb->prefix . 'twp_call_queues';
        
        return $wpdb->get_results("SELECT * FROM $table_name ORDER BY queue_name ASC");
    }
    
    /**
     * Delete queue
     */
    public static function delete_queue($queue_id) {
        global $wpdb;
        $queue_table = $wpdb->prefix . 'twp_call_queues';
        $calls_table = $wpdb->prefix . 'twp_queued_calls';
        
        // First delete all queued calls for this queue
        $wpdb->delete($calls_table, array('queue_id' => $queue_id), array('%d'));
        
        // Then delete the queue itself
        return $wpdb->delete($queue_table, array('id' => $queue_id), array('%d'));
    }
    
    /**
     * Get queue status
     */
    public static function get_queue_status() {
        global $wpdb;
        $queue_table = $wpdb->prefix . 'twp_call_queues';
        $calls_table = $wpdb->prefix . 'twp_queued_calls';
        
        $queues = $wpdb->get_results("SELECT * FROM $queue_table");
        
        $status = array();
        
        foreach ($queues as $queue) {
            $waiting_count = $wpdb->get_var($wpdb->prepare(
                "SELECT COUNT(*) FROM $calls_table WHERE queue_id = %d AND status = 'waiting'",
                $queue->id
            ));
            
            $status[] = array(
                'queue_id' => $queue->id,
                'queue_name' => $queue->queue_name,
                'waiting_calls' => $waiting_count,
                'max_size' => $queue->max_size,
                'available_slots' => $queue->max_size - $waiting_count
            );
        }
        
        return $status;
    }
}