<?php

namespace App\Helpers;

use App\Support\BillingCycleCatalog;
use App\Models\Invoice;
use App\Models\Order;
use Illuminate\Support\Str;

class OrderHelper
{
    /**
     * Generate a unique prefixed number.
     *
     * Examples:
     *   generateOrderNumber()        → ORD-A1B2C3D4
     *   generateOrderNumber('INV')   → INV-A1B2C3D4
     *
     * Uniqueness is guaranteed by checking the correct column on each model.
     */
    public static function generateOrderNumber(string $prefix = 'ORD'): string
    {
        do {
            $number = $prefix . '-' . strtoupper(Str::random(8));

            $exists = match ($prefix) {
                'INV' => Invoice::where('invoice_number', $number)->exists(),
                default => Order::where('order_num', $number)->exists(),
            };
        } while ($exists);

        return $number;
    }

    /**
     * @throws \InvalidArgumentException
     */
    public static function cycleToMonths(?string $cycle): int
    {
        $months = BillingCycleCatalog::monthsFor($cycle)
            ?? throw new \InvalidArgumentException("Unknown billing cycle: " . ($cycle ?? 'null'));

        return $months ?: 1;
    }
}