fix: enable bookings without ski passes

src/Validator/Constraints/SkiPassSelection.php

@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Validator\Constraints;
+
+use Symfony\Component\Validator\Constraint;
+
+/**
+ * Validates that a ski pass is selected whenever one is required.
+ *
+ * Applied on ParticipantEditDto because the decision needs the ParticipantEligibilityChecker,
+ * which a DTO callback cannot reach.
+ */
+#[\Attribute]
+class SkiPassSelection extends Constraint
+{
+    public string $message = 'Bitte auswählen';
+
+    public string $notBookableMessage = 'Für Teilnehmer:in {{ number }} ist keine Buchung möglich';
+
+    public function getTargets(): array|string
+    {
+        return static::CLASS_CONSTRAINT;
+    }
+}

src/Validator/Constraints/SkiPassSelectionValidator.php

@@ -0,0 +1,75 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Validator\Constraints;
+
+use App\Form\Model\BookingDto;
+use App\Form\Model\ParticipantEditDto;
+use App\Service\ParticipantEligibilityChecker;
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+use Symfony\Component\Validator\Exception\UnexpectedTypeException;
+
+/**
+ * Enforces ski pass selection for participants that need one.
+ *
+ * Three outcomes, mirroring what the form actually renders:
+ *
+ * - Ineligible participant: no ski pass is obtainable, so the ski pass field is not rendered
+ *   at all. Asking for a selection would be unsatisfiable - the booking is rejected as not
+ *   bookable instead.
+ * - Ski pass required and none selected: the regular "please select" violation.
+ * - Ski pass not required (baby, or a travel that offers no ski passes): no violation.
+ */
+class SkiPassSelectionValidator extends ConstraintValidator
+{
+    public function __construct(
+        private readonly ParticipantEligibilityChecker $participantEligibilityService,
+    ) {
+    }
+
+    public function validate(mixed $value, Constraint $constraint): void
+    {
+        if (false === $constraint instanceof SkiPassSelection) {
+            throw new UnexpectedTypeException($constraint, SkiPassSelection::class);
+        }
+
+        if (false === $value instanceof ParticipantEditDto) {
+            throw new UnexpectedTypeException($value, ParticipantEditDto::class);
+        }
+
+        // Skip validation in edit submissions - ski pass is readonly there.
+        if (BookingDto::MODE_EDIT === $value->bookingContext->getMode()) {
+            return;
+        }
+
+        $participant = $value->participant;
+
+        // Without a birth date nothing can be evaluated - the date of birth constraint reports it
+        if (null === $participant->dateOfBirth) {
+            return;
+        }
+
+        $participantIndex = $participant->index ?? 0;
+
+        if (false === $this->participantEligibilityService->isParticipantEligible($value->bookingContext, $participantIndex)) {
+            $this->context->buildViolation($constraint->notBookableMessage)
+                ->setParameter('{{ number }}', (string) ($participantIndex + 1))
+                ->atPath('participant.skiPass')
+                ->addViolation();
+
+            return;
+        }
+
+        if (false === $this->participantEligibilityService->isSkiPassRequired($value->bookingContext, $participantIndex)) {
+            return;
+        }
+
+        if (null === $participant->skiPass) {
+            $this->context->buildViolation($constraint->message)
+                ->atPath('participant.skiPass')
+                ->addViolation();
+        }
+    }
+}