fix: enable bookings without ski passes

src/Form/Model/ParticipantDto.php

@@ -102,8 +102,8 @@ class ParticipantDto
     /** @var list<int> */
     public array $autoBookOptOutRentalIds = [];
 
-    // Note: Ski pass validation is conditional - see ParticipantEditDto::validateSkiPassRequired()
-    // Babies (0-2 years) are exempt from ski pass requirement
+    // Note: Ski pass validation is conditional - see App\Validator\Constraints\SkiPassSelectionValidator.
+    // Babies (0-2 years) and travels that offer no ski passes at all are exempt.
     public ?Service $skiPass = null;
 
     /** @var list<Service> */

src/Form/Model/ParticipantEditDto.php

@@ -4,7 +4,6 @@ declare(strict_types=1);
 
 namespace App\Form\Model;
 
-use App\BusProNet\Constants;
 use App\Validator\Constraints as AppAssert;
 use Symfony\Component\Validator\Constraints as Assert;
 use Symfony\Component\Validator\Context\ExecutionContextInterface;
@@ -21,6 +20,7 @@ use function Symfony\Component\String\u;
 #[AppAssert\PurchaseVoucher(groups: ['booking_create', 'booking_edit'])]
 #[AppAssert\PromoVoucher(groups: ['booking_create', 'booking_edit'])]
 #[AppAssert\MandatoryAdditionalServicesSelected(groups: ['booking_create', 'booking_edit'])]
+#[AppAssert\SkiPassSelection(groups: ['strict_required'])]
 class ParticipantEditDto
 {
     public function __construct(
@@ -30,39 +30,6 @@ class ParticipantEditDto
     ) {
     }
 
-    /**
-     * Validates that ski pass is selected when required.
-     *
-     * Ski pass is required for all participants in create mode, EXCEPT for babies
-     * (participants aged 0-2 years at travel date). Babies don't qualify for any
-     * ski pass and the field is hidden for them.
-     *
-     * In edit submissions, this validation is skipped as the ski pass is readonly.
-     *
-     * This validation only runs when strict_required group is active.
-     */
-    #[Assert\Callback(groups: ['strict_required'])]
-    public function validateSkiPassRequired(ExecutionContextInterface $context): void
-    {
-        // Skip validation in edit submissions - ski pass is readonly there.
-        if (BookingDto::MODE_EDIT === $this->bookingContext->getMode()) {
-            return;
-        }
-
-        // Baby age exemption: skip validation for participants at or under BABY_MAX_AGE
-        $age = $this->participant->getAge($this->bookingContext->travel->dateFrom);
-        if (null !== $age && $age <= Constants::BABY_MAX_AGE) {
-            return;
-        }
-
-        // Ski pass is required for non-baby participants
-        if (null === $this->participant->skiPass) {
-            $context->buildViolation('Bitte auswählen')
-                ->atPath('participant.skiPass')
-                ->addViolation();
-        }
-    }
-
     /**
      * Validates that insurance is selected when required.
      *

src/Service/ParticipantEligibilityChecker.php

@@ -7,15 +7,22 @@ namespace App\Service;
 use App\BusProNet\Constants;
 use App\BusProNet\Model\Service;
 use App\Form\Model\BookingDto;
-use Carbon\CarbonImmutable;
+use App\Form\Service\ServiceAgeEvaluator;
 
 /**
  * Service for evaluating participant eligibility for booking.
  *
- * A participant is considered eligible when at least one skipass is available
- * for their age at the travel date. This service provides the business logic
- * for eligibility checks used by both the conditional field state system and
- * the view layer via Twig extension.
+ * Ski passes gate the booking process: a participant who cannot obtain one cannot book.
+ * This service owns that gate and distinguishes the two cases the travel data allows:
+ *
+ * - The travel offers ski passes, but none is selectable for the participant (age rules,
+ *   sold out, Buchungsstop) - the participant is ineligible and all service fields are hidden.
+ * - The travel offers no ski passes at all - rare, but legitimate. There is nothing to gate
+ *   on, so the participant is eligible and books without a pass, exactly like a baby does.
+ *
+ * Selectability is evaluated through the same pipeline the form uses to build the ski pass
+ * choices (ServiceAgeEvaluator + ServiceAvailabilityCalculator), so eligibility and the
+ * rendered choices cannot disagree.
  *
  * Results are cached per request using instance-level arrays to avoid redundant calculations
  * when checking the same participant multiple times.
@@ -25,11 +32,17 @@ class ParticipantEligibilityChecker
     /** @var array<string, bool> Request-scoped cache for participant eligibility */
     private array $eligibilityCache = [];
 
+    public function __construct(
+        private readonly ServiceAgeEvaluator $serviceAgeEvaluator,
+        private readonly ServiceAvailabilityCalculator $serviceAvailabilityCalculator,
+    ) {
+    }
+
     /**
      * Checks if a participant is eligible for booking.
      *
-     * Returns true when the participant can book services (at least one skipass available).
-     * Returns false when the participant cannot book (no skipasses available for their age).
+     * Returns true when the participant can book services, false when the booking process
+     * would be a dead end because no ski pass can be obtained for them.
      *
      * Baby age exemption: Participants aged 0-2 years (at travel date) are always eligible
      * regardless of skipass availability, as babies don't require ski passes.
@@ -39,7 +52,7 @@ class ParticipantEligibilityChecker
      * @param BookingDto $bookingDto       The current booking data
      * @param int        $participantIndex The index of the participant being evaluated
      *
-     * @return bool True if participant is eligible (has available skipasses or is baby age)
+     * @return bool True if participant is eligible (has a selectable skipass or needs none)
      */
     public function isParticipantEligible(BookingDto $bookingDto, int $participantIndex): bool
     {
@@ -49,7 +62,9 @@ class ParticipantEligibilityChecker
             return false;
         }
 
-        // Create cache key based on participant's birth date, travel date, and index
+        // Create cache key based on participant's birth date, travel date, and index.
+        // Selections of the other participants feed into availability but cannot change
+        // within a single request, so they need no representation in the key.
         $cacheKey = sprintf(
             'participant_eligibility_%s_%s_%d',
             $participant->dateOfBirth->format('Y-m-d'),
@@ -57,72 +72,85 @@ class ParticipantEligibilityChecker
             $participantIndex
         );
 
-        return $this->eligibilityCache[$cacheKey] ??= (function () use ($bookingDto, $participantIndex, $participant) {
-            // Baby age exemption: participants at or under BABY_MAX_AGE are always eligible
-            $age = $participant->getAge($bookingDto->travel->dateFrom);
-            if (null !== $age && $age <= Constants::BABY_MAX_AGE) {
+        return $this->eligibilityCache[$cacheKey] ??= (function () use ($bookingDto, $participantIndex) {
+            // Nothing gates the booking when no ski pass is required - baby age or a travel
+            // that does not offer ski passes at all
+            if (false === $this->isSkiPassRequired($bookingDto, $participantIndex)) {
                 return true;
             }
 
-            $allSkiPasses = $bookingDto->travel->getAdditionalServicesBySubTypes(Constants::TOKEN_SKI_PASS, true);
-            $availableSkiPasses = array_filter(
-                $allSkiPasses,
-                fn (Service $service) => $this->isSkiPassAvailableForParticipant($service, $bookingDto, $participantIndex)
-            );
-
-            return !empty($availableSkiPasses);
+            return [] !== $this->getSelectableSkiPasses($bookingDto, $participantIndex);
         })();
     }
 
     /**
-     * Checks if a skipass service is available for the given participant based on age constraints.
+     * Checks whether the participant has to select a ski pass to complete the booking.
+     *
+     * Returns false for babies, who never qualify for a pass, and for travels that offer no
+     * ski passes at all, where there is nothing to select.
+     *
+     * Note the asymmetry with eligibility: a travel that offers passes but has none left for
+     * the participant does NOT turn the pass optional. Such a booking has to stay blocked,
+     * not silently go through without a pass.
+     *
+     * @param BookingDto $bookingDto       The current booking data
+     * @param int        $participantIndex The index of the participant being evaluated
+     *
+     * @return bool True if a ski pass selection is required for this participant
      */
-    private function isSkiPassAvailableForParticipant(Service $service, BookingDto $bookingDto, int $participantIndex): bool
+    public function isSkiPassRequired(BookingDto $bookingDto, int $participantIndex): bool
     {
         $participant = $bookingDto->getParticipant($participantIndex);
 
-        if (null === $participant || null === $participant->dateOfBirth) {
+        if (null === $participant) {
             return false;
         }
 
-        // No age constraints = available to all
-        if (null === $service->ageConstraintType) {
-            return true;
+        // Baby age exemption: participants at or under BABY_MAX_AGE never need a ski pass
+        $age = $participant->getAge($bookingDto->travel->dateFrom);
+        if (null !== $age && $age <= Constants::BABY_MAX_AGE) {
+            return false;
         }
 
-        $travelStartDate = CarbonImmutable::instance($bookingDto->travel->dateFrom);
-        $birthDate = CarbonImmutable::instance($participant->dateOfBirth);
-        $ageAtTravelStart = (int) $birthDate->diffInYears($travelStartDate);
-        $birthYear = (int) $birthDate->format('Y');
+        return [] !== $this->getOfferedSkiPasses($bookingDto);
+    }
 
-        $constraintType = $service->ageConstraintType ?? 'absolute_age';
+    /**
+     * Collects the ski passes the participant could actually select.
+     *
+     * Applies the same filters as the form's ski pass choices: age constraints first, then
+     * availability (sold out at the API level, exhausted by the other participants of this
+     * booking, or on Buchungsstop).
+     *
+     * @param BookingDto $bookingDto       The current booking data
+     * @param int        $participantIndex The index of the participant being evaluated
+     *
+     * @return array<int, Service> The selectable ski pass services
+     */
+    private function getSelectableSkiPasses(BookingDto $bookingDto, int $participantIndex): array
+    {
+        $ageAppropriateSkiPasses = array_filter(
+            $this->getOfferedSkiPasses($bookingDto),
+            fn (Service $service) => false === $this->serviceAgeEvaluator->canEvaluate($service)
+                || true === $this->serviceAgeEvaluator->isServiceAvailableForParticipant($service, $bookingDto, $participantIndex)
+        );
 
-        if ('absolute_age' === $constraintType || 'mixed' === $constraintType) {
-            $minAge = $service->ageFrom;
-            $maxAge = $service->ageTo;
+        return $this->serviceAvailabilityCalculator->filterAvailableServices(
+            $ageAppropriateSkiPasses,
+            $bookingDto,
+            $participantIndex
+        );
+    }
 
-            if (null !== $minAge && $ageAtTravelStart < $minAge) {
-                return false;
-            }
-
-            if (null !== $maxAge && $ageAtTravelStart > $maxAge) {
-                return false;
-            }
-        }
-
-        if ('birth_year' === $constraintType || 'mixed' === $constraintType) {
-            $minBirthYear = $service->birthYearFrom;
-            $maxBirthYear = $service->birthYearTo;
-
-            if (null !== $minBirthYear && $birthYear < $minBirthYear) {
-                return false;
-            }
-
-            if (null !== $maxBirthYear && $birthYear > $maxBirthYear) {
-                return false;
-            }
-        }
-
-        return true;
+    /**
+     * Collects the ski passes the travel offers within its date range, ignoring the participant.
+     *
+     * @param BookingDto $bookingDto The current booking data
+     *
+     * @return array<int, Service> The ski pass services offered by the travel
+     */
+    private function getOfferedSkiPasses(BookingDto $bookingDto): array
+    {
+        return $bookingDto->travel->getAdditionalServicesBySubTypes(Constants::TOKEN_SKI_PASS, true);
     }
 }

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();
+        }
+    }
+}

tests/Form/Model/ParticipantEditDtoTest.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace App\Tests\Form\Model;
 
+use App\BusProNet\Constants;
 use App\BusProNet\Model\Booking;
 use App\BusProNet\Model\Address;
 use App\Form\Model\AddressDto;
@@ -17,10 +18,12 @@ use App\Form\Model\ParticipantEditDto;
 use App\Form\Service\ServiceAgeEvaluator;
 use App\Service\BookingPriceCalculator;
 use App\Service\ParticipantEligibilityChecker;
+use App\Service\ServiceAvailabilityCalculator;
 use App\Service\VoucherValidator;
 use App\Validator\Constraints\MandatoryAdditionalServicesSelectedValidator;
 use App\Validator\Constraints\PromoVoucherValidator;
 use App\Validator\Constraints\PurchaseVoucherValidator;
+use App\Validator\Constraints\SkiPassSelectionValidator;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Validator\Constraint;
 use Symfony\Component\Validator\Constraints\Email;
@@ -49,13 +52,21 @@ class ParticipantEditDtoTest extends TestCase
         $mockParticipantEligibilityChecker = $this->createMock(ParticipantEligibilityChecker::class);
         $mockServiceAgeEvaluator = $this->createMock(ServiceAgeEvaluator::class);
 
+        // Ski pass validation is exercised against the real gate, not a mock: which participant
+        // needs a pass is exactly the behaviour under test here.
+        $participantEligibilityChecker = new ParticipantEligibilityChecker(
+            new ServiceAgeEvaluator(),
+            new ServiceAvailabilityCalculator()
+        );
+
         // Create custom validator factory that can inject dependencies
-        $validatorFactory = new class($mockVoucherService, $mockPriceCalculatorService, $mockParticipantEligibilityChecker, $mockServiceAgeEvaluator) implements ConstraintValidatorFactoryInterface {
+        $validatorFactory = new class($mockVoucherService, $mockPriceCalculatorService, $mockParticipantEligibilityChecker, $mockServiceAgeEvaluator, $participantEligibilityChecker) implements ConstraintValidatorFactoryInterface {
             public function __construct(
                 private readonly VoucherValidator $voucherService,
                 private readonly BookingPriceCalculator $priceCalculatorService,
                 private readonly ParticipantEligibilityChecker $participantEligibilityService,
                 private readonly ServiceAgeEvaluator $serviceAgeEvaluator,
+                private readonly ParticipantEligibilityChecker $realEligibilityChecker,
             ) {
             }
 
@@ -75,6 +86,10 @@ class ParticipantEditDtoTest extends TestCase
                     return new EmailValidator(Email::VALIDATION_MODE_HTML5);
                 }
 
+                if (SkiPassSelectionValidator::class === $className) {
+                    return new SkiPassSelectionValidator($this->realEligibilityChecker);
+                }
+
                 if (MandatoryAdditionalServicesSelectedValidator::class === $className) {
                     return new MandatoryAdditionalServicesSelectedValidator(
                         $this->participantEligibilityService,
@@ -312,9 +327,7 @@ class ParticipantEditDtoTest extends TestCase
 
     public function testValidationInEditMode(): void
     {
-        $travel = new Travel();
-        $travel->dateFrom = new \DateTimeImmutable('2025-06-01');
-        $travel->dateTo = new \DateTimeImmutable('2025-06-08');
+        $travel = $this->createTravelOfferingSkiPasses();
 
         $bookingDto = new BookingDto($travel, 1); // hotelId must be int
 
@@ -483,9 +496,7 @@ class ParticipantEditDtoTest extends TestCase
 
     public function testSkiPassNotRequiredForTwoYearOldInCreateMode(): void
     {
-        $travel = new Travel();
-        $travel->dateFrom = new \DateTimeImmutable('2025-06-01');
-        $travel->dateTo = new \DateTimeImmutable('2025-06-08');
+        $travel = $this->createTravelOfferingSkiPasses();
 
         $bookingDto = new BookingDto($travel, 1);
 
@@ -520,9 +531,7 @@ class ParticipantEditDtoTest extends TestCase
 
     public function testSkiPassRequiredForThreeYearOldInCreateMode(): void
     {
-        $travel = new Travel();
-        $travel->dateFrom = new \DateTimeImmutable('2025-06-01');
-        $travel->dateTo = new \DateTimeImmutable('2025-06-08');
+        $travel = $this->createTravelOfferingSkiPasses();
 
         $bookingDto = new BookingDto($travel, 1);
 
@@ -555,11 +564,81 @@ class ParticipantEditDtoTest extends TestCase
         $this->assertCount(1, $skiPassViolations, 'Participant over BABY_MAX_AGE (3 years) should require ski pass');
     }
 
+    public function testSkiPassNotRequiredWhenTravelOffersNone(): void
+    {
+        $travel = $this->createTravelWithoutSkiPasses();
+
+        $bookingDto = new BookingDto($travel, 1);
+
+        $participant = $this->createParticipantWithoutSkiPass('[email protected]');
+        $participant->dateOfBirth = new \DateTimeImmutable('1990-01-01');
+        $participant->index = 0;
+        $participant->mobile = '+49 123 456789';
+        $participant->address = new Address();
+        $participant->address->street = 'Test Street 1';
+        $participant->address->postCode = '12345';
+        $participant->address->city = 'Test City';
+        $participant->address->country = 'DE';
+
+        $bookingDto->participants = [$participant];
+
+        $wrapper = new ParticipantEditDto(
+            participant: $bookingDto->participants[0],
+            bookingContext: $bookingDto,
+        );
+
+        $violations = $this->validator->validate($wrapper, null, ['strict_required']);
+
+        $skiPassViolations = array_filter(
+            iterator_to_array($violations),
+            fn ($v) => 'participant.skiPass' === $v->getPropertyPath()
+        );
+
+        $this->assertCount(0, $skiPassViolations, 'A travel offering no ski passes must be bookable without one');
+    }
+
+    public function testIneligibleParticipantIsReportedAsNotBookable(): void
+    {
+        // Ski passes exist, but the only one starts at 18 - a 14 year old cannot obtain any
+        $travel = $this->createTravelOfferingSkiPasses(ageFrom: 18);
+
+        $bookingDto = new BookingDto($travel, 1);
+
+        $participant = $this->createParticipantWithoutSkiPass('[email protected]');
+        $participant->dateOfBirth = $travel->dateFrom->modify('-14 years');
+        $participant->index = 0;
+        $participant->mobile = '+49 123 456789';
+        $participant->address = new Address();
+        $participant->address->street = 'Test Street 1';
+        $participant->address->postCode = '12345';
+        $participant->address->city = 'Test City';
+        $participant->address->country = 'DE';
+
+        $bookingDto->participants = [$participant];
+
+        $wrapper = new ParticipantEditDto(
+            participant: $bookingDto->participants[0],
+            bookingContext: $bookingDto,
+        );
+
+        $violations = $this->validator->validate($wrapper, null, ['strict_required']);
+
+        $skiPassViolations = array_values(array_filter(
+            iterator_to_array($violations),
+            fn ($v) => 'participant.skiPass' === $v->getPropertyPath()
+        ));
+
+        $this->assertCount(1, $skiPassViolations);
+        $this->assertSame(
+            'Für Teilnehmer:in 1 ist keine Buchung möglich',
+            $skiPassViolations[0]->getMessage(),
+            'The user must not be asked to select from a field that is not rendered'
+        );
+    }
+
     public function testSkiPassValidationSkippedInEditMode(): void
     {
-        $travel = new Travel();
-        $travel->dateFrom = new \DateTimeImmutable('2025-06-01');
-        $travel->dateTo = new \DateTimeImmutable('2025-06-08');
+        $travel = $this->createTravelOfferingSkiPasses();
 
         $bookingDto = new BookingDto($travel, 1);
 
@@ -599,9 +678,7 @@ class ParticipantEditDtoTest extends TestCase
 
     public function testEditSubmissionValidatesApplicantAddressOnlyForFirstParticipant(): void
     {
-        $travel = new Travel();
-        $travel->dateFrom = new \DateTimeImmutable('2025-06-01');
-        $travel->dateTo = new \DateTimeImmutable('2025-06-08');
+        $travel = $this->createTravelOfferingSkiPasses();
 
         $bookingDto = new BookingDto($travel, 1);
         $bookingDto->booking = new Booking();
@@ -644,9 +721,7 @@ class ParticipantEditDtoTest extends TestCase
 
     public function testSkiPassAgeCalculatedAtTravelDate(): void
     {
-        $travel = new Travel();
-        $travel->dateFrom = new \DateTimeImmutable('2025-06-01');
-        $travel->dateTo = new \DateTimeImmutable('2025-06-08');
+        $travel = $this->createTravelOfferingSkiPasses();
 
         $bookingDto = new BookingDto($travel, 1);
 
@@ -776,12 +851,42 @@ class ParticipantEditDtoTest extends TestCase
         $this->assertCount(1, $insuranceViolations);
     }
 
-    private function createBookingDtoWithParticipants(array $participants): BookingDto
+    /**
+     * Builds the default travel fixture: a regular travel that offers one unconstrained,
+     * available ski pass. Ski pass validation depends on the travel actually offering
+     * passes, so a travel without them is a distinct fixture, not the default.
+     */
+    private function createTravelOfferingSkiPasses(?int $ageFrom = null): Travel
+    {
+        $travel = $this->createTravelWithoutSkiPasses();
+
+        $skiPass = new Service();
+        $skiPass->id = 900;
+        $skiPass->label = 'Test Ski Pass';
+        $skiPass->subType = Constants::TOKEN_SKI_PASS;
+        $skiPass->available = 10;
+        $skiPass->price = 100.0;
+        $skiPass->ageConstraintType = null === $ageFrom ? null : 'absolute_age';
+        $skiPass->ageFrom = $ageFrom;
+
+        $travel->additionalServices = [900 => $skiPass];
+
+        return $travel;
+    }
+
+    private function createTravelWithoutSkiPasses(): Travel
     {
         $travel = new Travel();
         $travel->dateFrom = new \DateTimeImmutable('2025-06-01');
         $travel->dateTo = new \DateTimeImmutable('2025-06-08');
 
+        return $travel;
+    }
+
+    private function createBookingDtoWithParticipants(array $participants): BookingDto
+    {
+        $travel = $this->createTravelOfferingSkiPasses();
+
         $bookingDto = new BookingDto($travel, 1); // hotelId must be int
 
         // Set index for each participant

tests/Form/Service/CreateFieldStateProviderTest.php

@@ -9,7 +9,9 @@ use App\BusProNet\Model\Travel;
 use App\Form\Model\BookingDto;
 use App\Form\Model\ParticipantDto;
 use App\Form\Service\CreateFieldStateProvider;
+use App\Form\Service\ServiceAgeEvaluator;
 use App\Service\ParticipantEligibilityChecker;
+use App\Service\ServiceAvailabilityCalculator;
 use PHPUnit\Framework\TestCase;
 
 /**
@@ -24,7 +26,10 @@ class CreateFieldStateProviderTest extends TestCase
 
     protected function setUp(): void
     {
-        $this->provider = new CreateFieldStateProvider(new ParticipantEligibilityChecker());
+        $this->provider = new CreateFieldStateProvider(new ParticipantEligibilityChecker(
+            new ServiceAgeEvaluator(),
+            new ServiceAvailabilityCalculator()
+        ));
     }
 
     public function testDependentInsuranceFieldHidesWhenApplicantSelectsFamilyInsuranceThenReappearsAfterSwitch(): void

tests/Form/Service/ParticipantFieldOptionsProviderSkiPassAvailabilityTest.php

@@ -134,6 +134,17 @@ class ParticipantFieldOptionsProviderSkiPassAvailabilityTest extends TestCase
         }
     }
 
+    public function testTravelWithoutSkiPassesRendersNoField(): void
+    {
+        $bookingDto = $this->createBookingDto([]);
+
+        $this->assertSame(
+            [],
+            $this->provider->getFieldOptions('skiPass', $bookingDto, 0),
+            'The field has to be absent entirely, not rendered with an empty choice list'
+        );
+    }
+
     /** @return int[] */
     private function getSkiPassChoiceIds(BookingDto $bookingDto): array
     {

tests/Service/BookingEditPreFlightCheckerTest.php

@@ -21,6 +21,7 @@ use App\Form\Service\ServiceAgeEvaluator;
 use App\Validator\Constraints\MandatoryAdditionalServicesSelectedValidator;
 use App\Validator\Constraints\PromoVoucherValidator;
 use App\Validator\Constraints\PurchaseVoucherValidator;
+use App\Validator\Constraints\SkiPassSelectionValidator;
 use Carbon\CarbonImmutable;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Validator\Constraint;
@@ -291,6 +292,10 @@ class BookingEditPreFlightCheckerTest extends TestCase
                     );
                 }
 
+                if (SkiPassSelectionValidator::class === $className) {
+                    return new SkiPassSelectionValidator($this->participantEligibilityChecker);
+                }
+
                 return new $className();
             }
         };

tests/Service/ParticipantEligibilityCheckerTest.php

@@ -9,7 +9,9 @@ use App\BusProNet\Model\Service;
 use App\BusProNet\Model\Travel;
 use App\Form\Model\BookingDto;
 use App\Form\Model\ParticipantDto;
+use App\Form\Service\ServiceAgeEvaluator;
 use App\Service\ParticipantEligibilityChecker;
+use App\Service\ServiceAvailabilityCalculator;
 use PHPUnit\Framework\TestCase;
 
 class ParticipantEligibilityCheckerTest extends TestCase
@@ -18,7 +20,10 @@ class ParticipantEligibilityCheckerTest extends TestCase
 
     protected function setUp(): void
     {
-        $this->service = new ParticipantEligibilityChecker();
+        $this->service = new ParticipantEligibilityChecker(
+            new ServiceAgeEvaluator(),
+            new ServiceAvailabilityCalculator()
+        );
     }
 
     public function testBabyParticipantIsAlwaysEligible(): void
@@ -53,9 +58,9 @@ class ParticipantEligibilityCheckerTest extends TestCase
         $this->assertTrue($result, 'Participant at BABY_MAX_AGE (2 years) should be eligible');
     }
 
-    public function testThreeYearOldParticipantIsNotBabyEligible(): void
+    public function testThreeYearOldParticipantIsNotExemptAsBaby(): void
     {
-        $travel = $this->createTravelWithNoSkiPasses();
+        $travel = $this->createTravelWithSkiPasses(ageFrom: 6);
         $bookingDto = new BookingDto($travel, 1);
 
         // Create a participant just over BABY_MAX_AGE (3 years old at travel date)
@@ -64,9 +69,14 @@ class ParticipantEligibilityCheckerTest extends TestCase
         $participant->dateOfBirth = $travel->dateFrom->modify('-3 years');
         $bookingDto->participants[0] = $participant;
 
-        $result = $this->service->isParticipantEligible($bookingDto, 0);
-
-        $this->assertFalse($result, 'Participant over BABY_MAX_AGE (3 years) should not be eligible without ski passes');
+        $this->assertTrue(
+            $this->service->isSkiPassRequired($bookingDto, 0),
+            'Participant over BABY_MAX_AGE (3 years) should still need a ski pass'
+        );
+        $this->assertFalse(
+            $this->service->isParticipantEligible($bookingDto, 0),
+            'Participant over BABY_MAX_AGE (3 years) should not be eligible when no ski pass fits their age'
+        );
     }
 
     public function testAdultParticipantWithSkiPassIsEligible(): void
@@ -138,6 +148,128 @@ class ParticipantEligibilityCheckerTest extends TestCase
         $this->assertTrue($result, 'Age should be calculated at travel date, not current date');
     }
 
+    public function testAdultIsEligibleOnTravelWithoutSkiPasses(): void
+    {
+        $travel = $this->createTravelWithNoSkiPasses();
+        $bookingDto = new BookingDto($travel, 1);
+
+        $participant = new ParticipantDto();
+        $participant->index = 0;
+        $participant->dateOfBirth = $travel->dateFrom->modify('-25 years');
+        $bookingDto->participants[0] = $participant;
+
+        $this->assertFalse(
+            $this->service->isSkiPassRequired($bookingDto, 0),
+            'A travel that offers no ski passes cannot require one'
+        );
+        $this->assertTrue(
+            $this->service->isParticipantEligible($bookingDto, 0),
+            'Adult should be eligible on a travel that offers no ski passes at all'
+        );
+    }
+
+    public function testTeenagerIsEligibleOnTravelWithoutSkiPasses(): void
+    {
+        $travel = $this->createTravelWithNoSkiPasses();
+        $bookingDto = new BookingDto($travel, 1);
+
+        $participant = new ParticipantDto();
+        $participant->index = 0;
+        $participant->dateOfBirth = $travel->dateFrom->modify('-14 years');
+        $bookingDto->participants[0] = $participant;
+
+        $this->assertFalse($this->service->isSkiPassRequired($bookingDto, 0));
+        $this->assertTrue(
+            $this->service->isParticipantEligible($bookingDto, 0),
+            'Age must not be blamed when there is no ski pass to match against'
+        );
+    }
+
+    public function testParticipantIsNotEligibleWhenNoSkiPassMatchesTheirAge(): void
+    {
+        $travel = $this->createTravelWithSkiPasses(ageFrom: 18);
+        $bookingDto = new BookingDto($travel, 1);
+
+        $participant = new ParticipantDto();
+        $participant->index = 0;
+        $participant->dateOfBirth = $travel->dateFrom->modify('-14 years');
+        $bookingDto->participants[0] = $participant;
+
+        $this->assertTrue($this->service->isSkiPassRequired($bookingDto, 0));
+        $this->assertFalse(
+            $this->service->isParticipantEligible($bookingDto, 0),
+            'Ski passes exist but none fits the age - the participant stays ineligible'
+        );
+    }
+
+    public function testParticipantIsNotEligibleWhenSkiPassIsSoldOut(): void
+    {
+        $travel = $this->createTravelWithSkiPasses(available: 0);
+        $bookingDto = new BookingDto($travel, 1);
+
+        $participant = new ParticipantDto();
+        $participant->index = 0;
+        $participant->dateOfBirth = $travel->dateFrom->modify('-25 years');
+        $bookingDto->participants[0] = $participant;
+
+        $this->assertTrue(
+            $this->service->isSkiPassRequired($bookingDto, 0),
+            'A sold out ski pass must not turn the requirement off'
+        );
+        $this->assertFalse($this->service->isParticipantEligible($bookingDto, 0));
+    }
+
+    public function testParticipantIsNotEligibleWhenSkiPassIsOnBookingStop(): void
+    {
+        $travel = $this->createTravelWithSkiPasses(status: Constants::STATUS_BLOCKED);
+        $bookingDto = new BookingDto($travel, 1);
+
+        $participant = new ParticipantDto();
+        $participant->index = 0;
+        $participant->dateOfBirth = $travel->dateFrom->modify('-25 years');
+        $bookingDto->participants[0] = $participant;
+
+        $this->assertTrue($this->service->isSkiPassRequired($bookingDto, 0));
+        $this->assertFalse($this->service->isParticipantEligible($bookingDto, 0));
+    }
+
+    public function testParticipantIsNotEligibleWhenLastSkiPassIsTakenByAnotherParticipant(): void
+    {
+        $travel = $this->createTravelWithSkiPasses(available: 1);
+        $bookingDto = new BookingDto($travel, 2);
+
+        $firstParticipant = new ParticipantDto();
+        $firstParticipant->index = 0;
+        $firstParticipant->dateOfBirth = $travel->dateFrom->modify('-25 years');
+        $firstParticipant->skiPass = $travel->additionalServices[1];
+        $bookingDto->participants[0] = $firstParticipant;
+
+        $secondParticipant = new ParticipantDto();
+        $secondParticipant->index = 1;
+        $secondParticipant->dateOfBirth = $travel->dateFrom->modify('-25 years');
+        $bookingDto->participants[1] = $secondParticipant;
+
+        $this->assertTrue($this->service->isParticipantEligible($bookingDto, 0));
+        $this->assertFalse(
+            $this->service->isParticipantEligible($bookingDto, 1),
+            'The only ski pass is consumed by the first participant'
+        );
+    }
+
+    public function testBabyNeedsNoSkiPassEvenWhenTravelOffersThem(): void
+    {
+        $travel = $this->createTravelWithSkiPasses();
+        $bookingDto = new BookingDto($travel, 1);
+
+        $participant = new ParticipantDto();
+        $participant->index = 0;
+        $participant->dateOfBirth = $travel->dateFrom->modify('-1 year');
+        $bookingDto->participants[0] = $participant;
+
+        $this->assertFalse($this->service->isSkiPassRequired($bookingDto, 0));
+        $this->assertTrue($this->service->isParticipantEligible($bookingDto, 0));
+    }
+
     private function createTravelWithNoSkiPasses(): Travel
     {
         $travel = new Travel();
@@ -148,20 +280,22 @@ class ParticipantEligibilityCheckerTest extends TestCase
         return $travel;
     }
 
-    private function createTravelWithSkiPasses(): Travel
+    private function createTravelWithSkiPasses(?int $ageFrom = null, ?int $available = 10, ?string $status = null): Travel
     {
         $travel = new Travel();
         $travel->dateFrom = new \DateTimeImmutable('+30 days');
         $travel->dateTo = new \DateTimeImmutable('+37 days');
 
-        // Create a ski pass service available for all ages
+        // Create a ski pass service, by default available for all ages
         $skiPass = new Service();
         $skiPass->id = 1;
         $skiPass->label = 'Test Ski Pass';
         $skiPass->subType = Constants::TOKEN_SKI_PASS;
-        $skiPass->available = 10;
+        $skiPass->available = $available;
+        $skiPass->status = $status;
         $skiPass->price = 100.0;
-        $skiPass->ageConstraintType = null; // No age constraint
+        $skiPass->ageConstraintType = null === $ageFrom ? null : 'absolute_age';
+        $skiPass->ageFrom = $ageFrom;
         $skiPass->dateFrom = $travel->dateFrom;
         $skiPass->dateTo = $travel->dateTo;