feat: improved promotional and purchase vouchers

src/Validator/Constraints/PurchaseVoucherValidator.php

@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Validator\Constraints;
+
+use App\Form\Model\ParticipantEditDto;
+use App\Service\VoucherValidationService;
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+use Symfony\Component\Validator\Exception\UnexpectedTypeException;
+
+class PurchaseVoucherValidator extends ConstraintValidator
+{
+    public function __construct(
+        private readonly VoucherValidationService $voucherValidationService,
+    ) {
+    }
+
+    public function validate(mixed $value, Constraint $constraint): void
+    {
+        if (!$constraint instanceof PurchaseVoucher) {
+            throw new UnexpectedTypeException($constraint, PurchaseVoucher::class);
+        }
+
+        if (!$value instanceof ParticipantEditDto) {
+            throw new UnexpectedTypeException($value, ParticipantEditDto::class);
+        }
+
+        $voucherCode = $value->participant->purchaseVoucherCode;
+
+        // Skip validation if voucher code is empty
+        if (null === $voucherCode || '' === trim($voucherCode)) {
+            return;
+        }
+
+        // Validate voucher via API
+        $result = $this->voucherValidationService->validatePurchaseVoucher($voucherCode);
+
+        // Add violation if voucher is invalid
+        if (false === $result->isValid) {
+            $this->context->buildViolation($constraint->message)
+                ->setParameter('{{ error }}', $result->errorMessage ?? 'Unbekannter Fehler')
+                ->atPath('participant.purchaseVoucherCode')
+                ->addViolation();
+        }
+    }
+}