[Bug] Fix issue after paypal checkout (#355)

| Q               | A
| --------------- | -----
| Branch?         | 1.6
| Bug fix?        | yes
| New feature?    | no
| Related tickets | n/a

Author: GSadee

spec/Processor/PayPalOrderCompleteProcessorSpec.php

@@ -20,12 +20,15 @@
 use Sylius\Component\Core\Model\PaymentInterface;
 use Sylius\Component\Core\Model\PaymentMethodInterface;
 use Sylius\PayPalPlugin\Manager\PaymentStateManagerInterface;
+use Sylius\PayPalPlugin\Verifier\PaymentAmountVerifierInterface;
 
 final class PayPalOrderCompleteProcessorSpec extends ObjectBehavior
 {
-    function let(PaymentStateManagerInterface $paymentStateManager): void
-    {
-        $this->beConstructedWith($paymentStateManager);
+    function let(
+        PaymentStateManagerInterface $paymentStateManager,
+        PaymentAmountVerifierInterface $paymentAmountVerifier,
+    ): void {
+        $this->beConstructedWith($paymentStateManager, $paymentAmountVerifier);
     }
 
     function it_completes_pay_pal_order(
@@ -34,12 +37,14 @@ function it_completes_pay_pal_order(
         PaymentInterface $payment,
         PaymentMethodInterface $paymentMethod,
         GatewayConfigInterface $gatewayConfig,
+        PaymentAmountVerifierInterface $paymentAmountVerifier,
     ): void {
         $order->getLastPayment(PaymentInterface::STATE_PROCESSING)->willReturn($payment);
 
         $payment->getMethod()->willReturn($paymentMethod);
         $paymentMethod->getGatewayConfig()->willReturn($gatewayConfig);
         $gatewayConfig->getFactoryName()->willReturn('sylius.pay_pal');
+        $paymentAmountVerifier->verify($payment)->shouldBeCalled();
 
         $paymentStateManager->complete($payment)->shouldBeCalled();
 

src/Processor/PayPalOrderCompleteProcessor.php

@@ -17,15 +17,24 @@
 use Sylius\Component\Core\Model\OrderInterface;
 use Sylius\Component\Core\Model\PaymentInterface;
 use Sylius\Component\Core\Model\PaymentMethodInterface;
+use Sylius\PayPalPlugin\Exception\PaymentAmountMismatchException;
 use Sylius\PayPalPlugin\Manager\PaymentStateManagerInterface;
+use Sylius\PayPalPlugin\Verifier\PaymentAmountVerifierInterface;
 
 final class PayPalOrderCompleteProcessor
 {
-    private PaymentStateManagerInterface $paymentStateManager;
-
-    public function __construct(PaymentStateManagerInterface $paymentStateManager)
-    {
-        $this->paymentStateManager = $paymentStateManager;
+    public function __construct(
+        private PaymentStateManagerInterface $paymentStateManager,
+        private ?PaymentAmountVerifierInterface $paymentAmountVerifier = null,
+    ) {
+        if (null === $this->paymentAmountVerifier) {
+            trigger_deprecation(
+                'sylius/paypal-plugin',
+                '1.6',
+                'Not passing an instance of "%s" as the second argument is deprecated and will be prohibited in 3.0.',
+                PaymentAmountVerifierInterface::class,
+            );
+        }
     }
 
     public function completePayPalOrder(OrderInterface $order): void
@@ -44,6 +53,34 @@ public function completePayPalOrder(OrderInterface $order): void
             return;
         }
 
+        try {
+            if (null !== $this->paymentAmountVerifier) {
+                $this->paymentAmountVerifier->verify($payment);
+            } else {
+                $this->verify($payment);
+            }
+        } catch (PaymentAmountMismatchException) {
+            $this->paymentStateManager->cancel($payment);
+
+            return;
+        }
+
         $this->paymentStateManager->complete($payment);
     }
+
+    private function verify(PaymentInterface $payment): void
+    {
+        $totalAmount = $this->getTotalPaymentAmountFromPaypal($payment);
+
+        if ($payment->getOrder()->getTotal() !== $totalAmount) {
+            throw new PaymentAmountMismatchException();
+        }
+    }
+
+    private function getTotalPaymentAmountFromPaypal(PaymentInterface $payment): int
+    {
+        $details = $payment->getDetails();
+
+        return $details['payment_amount'] ?? 0;
+    }
 }

src/Resources/config/services.xml

@@ -132,6 +132,7 @@
 
         <service id="Sylius\PayPalPlugin\Processor\PayPalOrderCompleteProcessor" public="true">
             <argument type="service" id="Sylius\PayPalPlugin\Manager\PaymentStateManagerInterface" />
+            <argument type="service" id="sylius_paypal.verifier.payment_amount" />
         </service>
 
         <service