<?php
namespace AIZLabs\ChatAgent;

class FunctionHandler {
    protected static array $function_map = [
        'aizl_track_order' => ['internal_function_track_order'],
        'aizl_track_ticket' => ['internal_function_track_ticket'],
        'aizl_get_bestsellers' => ['internal_function_get_bestsellers'],
    ];

    protected static array $handlers = [];

    public static function register_handler(string $class_name): string {
        if (!class_exists($class_name)) {
            return "Error: Handler class $class_name does not exist";
        }
        if (!is_subclass_of($class_name, self::class)) {
            return "Error: $class_name must extend " . self::class;
        }
        self::$handlers[$class_name] = $class_name;
        return "Handler $class_name registered successfully";
    }

    public static function internal_call(string $function_name, array $args = []) {
        $map = array_merge(self::$function_map, apply_filters('aizl_function_map', []));
        
        if (!isset($map[$function_name])) {
            return "Function $function_name not available";
        }

        $method = $map[$function_name][0];

        // Check main class first
        if (method_exists(self::class, $method)) {
            return self::$method($args);
        }

        // Check registered handlers
        foreach (self::$handlers as $handler_class) {
            if (method_exists($handler_class, $method)) {
                return $handler_class::$method($args);
            }
        }

        return "No handler available for $function_name (method: $method)";
    }


    // Accepts an associative array of arguments
    public static function internal_function_track_order($args) {
        $order_id = $args['order_id'] ?? null;
        if (!$order_id) {
            $result = json_encode([
                'order_status' => 'No Order ID'
            ]);
            return $result;
        }

        global $wpdb;
        $table = esc_sql($wpdb->prefix . 'wc_order_stats');
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Querying WooCommerce custom table, table name is escaped
        $status = $wpdb->get_var($wpdb->prepare("SELECT status FROM `{$table}` WHERE order_id = %s", $order_id));
        if (!$status) { 
            $result = json_encode([
                'order_status' => 'Order not found'
            ]);
            return $result;
        } else {
            $result = json_encode([
                'order_status' => $status
            ]);
            return $result;
        }
    }

    public static function internal_function_track_ticket($args) {
        $ticket_number = $args['ticket_number'] ?? null;
        $email = $args['email'] ?? null;
        
        if (!$ticket_number || !$email) {
            $result = json_encode([
                'error' => 'Ticket number and email are required'
            ]);
            return $result;
        }

        global $wpdb;

        // Check if SupportCandy tables exist
        $tickets_table = esc_sql($wpdb->prefix . 'psmsc_tickets');
        $customers_table = esc_sql($wpdb->prefix . 'psmsc_customers');
        $threads_table = esc_sql($wpdb->prefix . 'psmsc_threads');
        $statuses_table = esc_sql($wpdb->prefix . 'psmsc_statuses');

        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Checking for SupportCandy plugin tables
        if ($wpdb->get_var($wpdb->prepare("SHOW TABLES LIKE %s", $tickets_table)) != $tickets_table) {
            $result = json_encode([
                'error' => 'SupportCandy plugin not found or not active'
            ]);
            return $result;
        }
        
        // Get ticket information with status and customer details
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Querying SupportCandy custom tables, table names are escaped
        $ticket = $wpdb->get_row($wpdb->prepare("SELECT t.id, t.id as ticket_number, s.name as status_name, s.color, c.name as customer_name, c.email as customer_email, t.date_created, t.date_updated FROM `{$tickets_table}` t JOIN `{$customers_table}` c ON t.customer = c.id LEFT JOIN `{$statuses_table}` s ON t.status = s.id WHERE t.id = %s AND c.email = %s", $ticket_number, $email));
        
        if (!$ticket) {
            $result = json_encode([
                'error' => 'Ticket not found or email does not match'
            ]);
            return $result;
        }
        
        // Get latest thread/message
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Querying SupportCandy custom tables, table name is escaped
        $latest_thread = $wpdb->get_row($wpdb->prepare("SELECT body, type, date_created FROM `{$threads_table}` WHERE ticket = %d AND is_active = 1 AND type != 'log' ORDER BY date_created DESC LIMIT 1", $ticket->id));
        
        $result = json_encode([
            'ticket_number' => $ticket->ticket_number,
            'status' => $ticket->status_name ?: 'Unknown',
            'status_color' => $ticket->color ?: '#999999',
            'customer_name' => $ticket->customer_name,
            'date_created' => $ticket->date_created,
            'last_updated' => $ticket->date_updated,
            'latest_message' => [
                'content' => $latest_thread ? wp_strip_all_tags($latest_thread->body) : 'No messages found',
                'type' => $latest_thread ? $latest_thread->type : 'system',
                'date' => $latest_thread ? $latest_thread->date_created : $ticket->date_created
            ]
        ]);
        
        return $result;
    }

    public static function internal_function_get_bestsellers($args) {
        // Check if WooCommerce is active
        if (!class_exists('WooCommerce')) {
            return json_encode([
                'error' => 'WooCommerce plugin is not active'
            ]);
        }

        global $wpdb;
        $lookup_table = esc_sql($wpdb->prefix . 'wc_order_product_lookup');

        // Check if the analytics table exists
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Checking for WooCommerce Analytics table
        if ($wpdb->get_var($wpdb->prepare("SHOW TABLES LIKE %s", $lookup_table)) != $lookup_table) {
            return json_encode([
                'error' => 'WooCommerce analytics table not found'
            ]);
        }

        // Get top 5 bestselling products
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Querying WooCommerce Analytics custom tables, table name is escaped
        $bestsellers = $wpdb->get_results("SELECT p.ID as product_id, p.post_title as product_name, SUM(ol.product_qty) as total_sold, pm.meta_value as price FROM `{$lookup_table}` ol JOIN {$wpdb->posts} p ON ol.product_id = p.ID LEFT JOIN {$wpdb->postmeta} pm ON p.ID = pm.post_id AND pm.meta_key = '_price' WHERE p.post_status = 'publish' AND p.post_type = 'product' GROUP BY ol.product_id ORDER BY total_sold DESC LIMIT 5");

        if (empty($bestsellers)) {
            return json_encode([
                'message' => 'No sales data available yet'
            ]);
        }

        $result = [];
        foreach ($bestsellers as $product) {
            $result[] = [
                'product_id' => $product->product_id,
                'name' => $product->product_name,
                'total_sold' => (int)$product->total_sold,
                'price' => $product->price ? '$' . number_format((float)$product->price, 2) : 'Price not available',
                'url' => get_permalink($product->product_id)
            ];
        }

        return json_encode([
            'bestsellers' => $result,
            'count' => count($result)
        ]);
    }

}