ساده‌ترین تعریف Factory Pattern

$payment = new ZarinpalPayment();

interface Payment
{
    public function pay();
}


class ZarinpalPayment implements Payment
{
    public function pay()
    {
        return "پرداخت با زرین‌پال";
    }
}

class IdpayPayment implements Payment
{
    public function pay()
    {
        return "پرداخت با IDPay";
    }
}

class PaymentFactory
{
    public static function make(string $type): Payment
    {
        return match ($type) {
            'zarinpal' => new ZarinpalPayment(),
            'idpay'    => new IdpayPayment(),
            default    => throw new Exception('درگاه نامعتبر است'),
        };
    }
}

$payment = PaymentFactory::make('zarinpal');


echo $payment->pay();

$payment = PaymentFactory::make('idpay');

echo $payment->pay();

if ($type === 'zarinpal') {
    $payment = new ZarinpalPayment();
} elseif ($type === 'idpay') {
    $payment = new IdpayPayment();
}

$payment = PaymentFactory::make($type);