<?php

namespace App\Helper;

use Carbon\Carbon;
use Illuminate\Support\Facades\DB;
use Modules\Restaurant\Models\Order;

class OrderHelper
{
    /**
     * Generate a unique order number for the restaurant.
     *
     * Format: ORD-{YYYYMMDD}-{RestaurantId}-{AutoIncrement}
     */
    public static function generateOrderNumber(int $restaurantId): string
    {
        $today = Carbon::now()->format('Ymd');

        // Fetch last order (including soft-deleted)
        $lastOrder = DB::table('orders')
            ->where('restaurant_id', $restaurantId)
            ->whereDate('created_at', Carbon::today())
            ->orderByDesc('id')
            ->first();

        $lastIncrement = 0;

        if ($lastOrder && preg_match('/ORD-\d{8}-\d+-([\d]+)/', $lastOrder->order_number, $matches)) {
            $lastIncrement = (int) $matches[1];
        }

        $newIncrement = $lastIncrement + 1;

        // Ensure unique, retry if needed (handles rare race conditions)
        do {
            $orderNumber = sprintf('ORD-%s-%d-%04d', $today, $restaurantId, $newIncrement);
            $exists = Order::withTrashed()->where('order_number', $orderNumber)->exists();

            if ($exists) {
                $newIncrement++;
            }
        } while ($exists);

        return $orderNumber;
    }
}