JobcardSystem/app/Domain/Jobcard/JobcardReference.php

<?php
declare(strict_types=1);

namespace App\Domain\Jobcard;

final class JobcardReference
{
    public static function generate(int $sequence, ?int $year = null): string
    {
        if ($sequence < 1 || $sequence > 999999) {
            throw new \InvalidArgumentException('Sequence must be between 1 and 999999.');
        }
        $year ??= (int) date('Y');
        if ($year < 2000 || $year > 9999) {
            throw new \InvalidArgumentException('Year must be four digits.');
        }
        return sprintf('JC-%04d-%06d', $year, $sequence);
    }

    public static function isValid(string $reference): bool
    {
        return preg_match('/^JC-\d{4}-\d{6}$/', $reference) === 1;
    }
}