feat: unique email addresses of participants unless child, cleanup

addresses #869axbn21

config/services.yaml

@@ -91,6 +91,7 @@ services:
                 - 'App\Form\Service\ParticipantParkingFieldHandler'
                 - 'App\Form\Service\ParticipantRentalInsuranceFieldHandler'
                 - 'App\Form\Service\ParticipantLicensePlateFieldHandler'
+                - 'App\Form\Service\ParticipantEmailFieldHandler'
                 # Complex handlers with dependencies - use service references
                 - '@App\Form\Service\ParticipantBulkInsuranceFieldHandler'
                 - '@App\Form\Service\ParticipantInsuranceFieldHandler'

src/BusProNet/Model/Insurance.php

@@ -17,7 +17,7 @@ use Symfony\Component\Serializer\Normalizer\DateTimeNormalizer;
 class Insurance
 {
     #[Groups(['api:single', 'api:list'])]
-    public string|null $id = null;
+    public ?string $id = null;
 
     #[Groups(['api:single', 'api:list'])]
     public ?string $code = null;

src/Controller/Booking/Create/Step2Controller.php

@@ -96,10 +96,13 @@ class Step2Controller extends AbstractController
             return $this->hxRedirect($request, $this->generateUrl('app_booking_create_step_3'));
         }
 
-        // Extract participant indices with validation errors
+        // Extract participant validation errors
-        $participantErrors = [];
+        $participantErrorIndices = [];
+        $participantErrorMessages = [];
         if (true === $form->isSubmitted() && false === $form->isValid()) {
-            $participantErrors = $this->extractParticipantErrorIndices($form);
+            $extractedErrors = $this->extractParticipantValidationErrors($form);
+            $participantErrorIndices = $extractedErrors['errorIndices'];
+            $participantErrorMessages = $extractedErrors['errorMessages'];
         }
 
         // Generate cards data
@@ -117,7 +120,8 @@ class Step2Controller extends AbstractController
             'cardsData' => $cardsData,
             'summaryData' => $summaryData,
             'pricingData' => $summary['pricing'],
-            'participantErrors' => $participantErrors,
+            'participantErrors' => $participantErrorIndices,
+            'participantErrorMessages' => $participantErrorMessages,
         ];
 
         // HTMX request: render blocks only

src/Controller/Booking/Edit/IndexController.php

@@ -156,10 +156,13 @@ class IndexController extends AbstractController
             return $this->hxRedirect($request, $this->generateUrl('app_booking_edit', ['id' => $id]));
         }
 
-        // Extract participant indices with validation errors
+        // Extract participant validation errors
         $participantErrors = [];
+        $participantErrorMessages = [];
         if ($form->isSubmitted() && false === $form->isValid()) {
-            $participantErrors = $this->extractParticipantErrorIndices($form);
+            $extractedErrors = $this->extractParticipantValidationErrors($form);
+            $participantErrors = $extractedErrors['errorIndices'];
+            $participantErrorMessages = $extractedErrors['errorMessages'];
         }
 
         // Generate card data for all participants
@@ -189,6 +192,7 @@ class IndexController extends AbstractController
             'isDirty' => $this->fingerprintService->isDirty($bookingDto),
             'hasValidationErrors' => count($participantErrors) > 0,
             'participantErrors' => $participantErrors,
+            'participantErrorMessages' => $participantErrorMessages,
         ];
 
         // If HTMX request, render only blocks to avoid layout duplication

src/Controller/Booking/Traits/ParticipantValidationTrait.php

@@ -13,16 +13,18 @@ namespace App\Controller\Booking\Traits;
 trait ParticipantValidationTrait
 {
     /**
-     * Extracts participant indices that have validation errors.
+     * Extracts participant validation errors from form.
      *
-     * Parses form errors to identify which participants have validation issues.
+     * Returns two arrays:
-     * Returns an array of participant indices (e.g., [0, 2, 5]).
+     * - errorIndices: Array of participant indices with errors (e.g., [0, 2, 5])
+     * - errorMessages: Map of participant index to error messages (e.g., [0 => ['E-Mail: ...', 'Vorname: ...']])
      *
-     * @return array<int> Array of participant indices with errors
+     * @return array{errorIndices: array<int>, errorMessages: array<int, array<string>>}
      */
-    private function extractParticipantErrorIndices($form): array
+    private function extractParticipantValidationErrors($form): array
     {
         $errorIndices = [];
+        $errorMessages = [];
         $errors = $form->getErrors(true); // Get all errors recursively
 
         foreach ($errors as $error) {
@@ -31,13 +33,66 @@ trait ParticipantValidationTrait
                 continue;
             }
 
-            // Property paths look like "participants[0].firstName" or "participants[1].email"
+            // Property paths from BookingDto validation look like "participants[0].email"
-            if (preg_match('/participants\[(\d+)]/', $propertyPath, $matches)) {
+            // Note: Using more flexible regex to capture field path after index
+            if (preg_match('/participants\[(\d+)\]\.?(.*)/', (string) $propertyPath, $matches)) {
                 $index = (int) $matches[1];
-                $errorIndices[$index] = true; // Use array key to avoid duplicates
+                $fieldPath = $matches[2] ?? '';
+                $message = $error->getMessage();
+
+                // Mark this participant as having errors
+                $errorIndices[$index] = true;
+
+                // Initialize error messages array for this participant if needed
+                if (false === isset($errorMessages[$index])) {
+                    $errorMessages[$index] = [];
+                }
+
+                // Add formatted error message
+                $errorMessages[$index][] = $this->formatErrorMessage($fieldPath, $message);
             }
         }
 
-        return array_keys($errorIndices);
+        return [
+            'errorIndices' => array_keys($errorIndices),
+            'errorMessages' => $errorMessages,
+        ];
+    }
+
+    /**
+     * Formats an error message with field context.
+     *
+     * @param string $fieldPath The field path that has the error (may be empty or nested)
+     * @param string $message   The error message
+     *
+     * @return string Formatted error message
+     */
+    private function formatErrorMessage(string $fieldPath, string $message): string
+    {
+        // If no field path, return just the message (error is on participant level)
+        if ('' === trim($fieldPath)) {
+            return $message;
+        }
+
+        // Extract the first part of the path for nested fields (e.g., "address.street" -> "address")
+        $fieldName = explode('.', $fieldPath)[0];
+
+        // Field name translations for better user understanding
+        $fieldLabels = [
+            'email' => 'E-Mail',
+            'firstName' => 'Vorname',
+            'lastName' => 'Nachname',
+            'dateOfBirth' => 'Geburtsdatum',
+            'assignedRoomId' => 'Zimmer',
+            'skiPass' => 'Skipass',
+            'transportationOutbound' => 'Anreise',
+            'transportationInbound' => 'Rückreise',
+            'mobile' => 'Mobilnummer',
+            'address' => 'Adresse',
+        ];
+
+        $fieldLabel = $fieldLabels[$fieldName] ?? $fieldName;
+
+        return sprintf('%s: %s', $fieldLabel, $message);
     }
 }

src/Form/BankAccountType.php

@@ -36,7 +36,7 @@ class BankAccountType extends AbstractType
                 ],
             ])
             ->add('sepaMandateAccepted', CheckboxType::class, [
-                'label' => '<span class="text-gray-700 font-normal">Hiermit ermächtige/n ich/wir Sie widerruflich, die von mir/uns zu entrichtende Zahlung bei Fälligkeit zu Lasten meines/unseres Girokontos durch Lastschrift einzuziehen.</span><br>' .
+                'label' => '<span class="text-gray-700 font-normal">Hiermit ermächtige/n ich/wir Sie widerruflich, die von mir/uns zu entrichtende Zahlung bei Fälligkeit zu Lasten meines/unseres Girokontos durch Lastschrift einzuziehen.</span><br>'.
                     '<span class="text-red-600 font-semibold">Bei kurzfristigen Buchungen (ab 2 Wochen vor Reisebeginn) ist Lastschrift NICHT mehr möglich.</span>',
                 'required' => true,
                 'label_html' => true,

src/Form/BookingParticipantType.php

@@ -213,7 +213,7 @@ class BookingParticipantType extends AbstractType
      * @param FormInterface        $form             The form to modify
      * @param BookingDto           $bookingDto       The booking data for context
      * @param int                  $participantIndex The participant index
-     * @param array<string, mixed> $submittedData         Submitted form data for state calculation
+     * @param array<string, mixed> $submittedData    Submitted form data for state calculation
      */
     private function removeExcludedFields(FormInterface $form, BookingDto $bookingDto, int $participantIndex, array &$submittedData = []): void
     {

src/Form/Model/BookingDto.php

@@ -195,4 +195,44 @@ class BookingDto
                 ->addViolation();
         }
     }
+
+    #[Assert\Callback(groups: ['booking_create_step_2', 'booking_edit'])]
+    public function validateEmailUniqueness(ExecutionContextInterface $context): void
+    {
+        // Build map of email addresses to participant indices (adults only)
+        $emailMap = [];
+
+        foreach ($this->participants as $index => $participant) {
+            // Skip children (they can share email addresses)
+            if (true === $participant->isChild()) {
+                continue;
+            }
+
+            // Skip null or empty emails (handled by other validators)
+            if (null === $participant->email || '' === trim($participant->email)) {
+                continue;
+            }
+
+            // Normalize email for case-insensitive comparison
+            $normalizedEmail = strtolower(trim($participant->email));
+
+            // Add participant index to the email map
+            if (false === isset($emailMap[$normalizedEmail])) {
+                $emailMap[$normalizedEmail] = [];
+            }
+            $emailMap[$normalizedEmail][] = $index;
+        }
+
+        // Add validation errors for duplicate emails
+        foreach ($emailMap as $email => $indices) {
+            // Only add violations if email is used by multiple adult participants
+            if (1 < count($indices)) {
+                foreach ($indices as $index) {
+                    $context->buildViolation('Diese E-Mail Adresse wird bereits von einem anderen erwachsenen Teilnehmer verwendet')
+                        ->atPath(sprintf('participants[%d].email', $index))
+                        ->addViolation();
+                }
+            }
+        }
+    }
 }

src/Form/Model/ParticipantDto.php

@@ -224,4 +224,26 @@ class ParticipantDto
             'message' => $message,
         ];
     }
+
+    /**
+     * Determines if the participant is a child based on age at current date.
+     *
+     * A child is defined as someone under the specified age threshold (default: 16 years).
+     * This classification is used for email uniqueness validation (children can share emails with adults).
+     *
+     * @param int $ageThreshold The age threshold for child classification (default: 16)
+     *
+     * @return bool True if participant is under the age threshold, false otherwise or if age unknown
+     */
+    public function isChild(int $ageThreshold = 16): bool
+    {
+        $age = $this->getAge();
+
+        // Treat unknown age as adult for safety (requires email uniqueness)
+        if (null === $age) {
+            return false;
+        }
+
+        return $ageThreshold > $age;
+    }
 }

src/Form/Service/Abstract/AbstractFieldOptionsProvider.php

@@ -36,10 +36,10 @@ abstract class AbstractFieldOptionsProvider implements FieldOptionsProviderInter
      * used when building the form field. These options are merged with any
      * static options defined in the form type.
      *
-     * @param string              $fieldName        The name of the field to configure
+     * @param string     $fieldName        The name of the field to configure
      * @param BookingDto $bookingDto       The current booking data for context (create or edit)
-     * @param int                 $participantIndex The index of the participant being configured
+     * @param int        $participantIndex The index of the participant being configured
-     * @param array               $options          Additional options to customize field behavior
+     * @param array      $options          Additional options to customize field behavior
      *
      * @return array<string, mixed> Symfony form field options, or empty array if field not supported
      */

src/Form/Service/Abstract/AbstractFieldStateProvider.php

@@ -36,7 +36,7 @@ abstract class AbstractFieldStateProvider implements FieldStateProviderInterface
      * condition independently to allow early field exclusion.
      *
      * @param string               $fieldName        The name of the field to evaluate
-     * @param BookingDto  $bookingDto       The current booking data for context (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data for context (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data for condition evaluation
      *
@@ -64,7 +64,7 @@ abstract class AbstractFieldStateProvider implements FieldStateProviderInterface
      * excluded from the form entirely rather than hidden with CSS.
      *
      * @param string               $fieldName        The name of the field to evaluate
-     * @param BookingDto  $bookingDto       The current booking data for context (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data for context (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data for condition evaluation
      *
@@ -139,7 +139,7 @@ abstract class AbstractFieldStateProvider implements FieldStateProviderInterface
     /**
      * Calculates field states for all configured fields at once.
      *
-     * @param BookingDto  $bookingDto       The current booking data for context (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data for context (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data for condition evaluation
      *

src/Form/Service/Abstract/AbstractParticipantFieldHandler.php

@@ -57,7 +57,7 @@ abstract class AbstractParticipantFieldHandler implements ParticipantFieldHandle
      * participant doesn't exist, preventing array access errors.
      *
      * @param BookingDto $bookingDto       The booking DTO containing participants (create or edit)
-     * @param int                 $participantIndex The index of the participant to retrieve
+     * @param int        $participantIndex The index of the participant to retrieve
      *
      * @return object|null The participant object, or null if not found
      */
@@ -82,7 +82,7 @@ abstract class AbstractParticipantFieldHandler implements ParticipantFieldHandle
      */
     protected function isEditMode(BookingDto $bookingDto): bool
     {
-        return $bookingDto->mode === BookingDto::MODE_EDIT;
+        return BookingDto::MODE_EDIT === $bookingDto->mode;
     }
 
     /**
@@ -94,7 +94,7 @@ abstract class AbstractParticipantFieldHandler implements ParticipantFieldHandle
      */
     protected function isCreateMode(BookingDto $bookingDto): bool
     {
-        return $bookingDto->mode === BookingDto::MODE_CREATE;
+        return BookingDto::MODE_CREATE === $bookingDto->mode;
     }
 
     /**
@@ -159,7 +159,7 @@ abstract class AbstractParticipantFieldHandler implements ParticipantFieldHandle
      * processing results.
      *
      * @param array<string, mixed> $submittedData    The submitted participant form data
-     * @param BookingDto  $bookingDto       The booking DTO (potentially modified by processing)
+     * @param BookingDto           $bookingDto       The booking DTO (potentially modified by processing)
      * @param int                  $participantIndex The participant index being processed
      *
      * @return array<string, array<string, mixed>> Empty array (no state modifications by default)

src/Form/Service/Condition/AgeRangeCondition.php

@@ -54,7 +54,7 @@ class AgeRangeCondition implements FieldConditionInterface
      * checks if it falls within the configured age range. Returns false if
      * the participant has no date of birth set.
      *
-     * @param BookingDto  $bookingDto       The current booking data (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data (unused for age conditions)
      *

src/Form/Service/Condition/ApplicantCondition.php

@@ -21,7 +21,7 @@ class ApplicantCondition implements FieldConditionInterface
     /**
      * Evaluates if the participant is the applicant.
      *
-     * @param BookingDto  $bookingDto       The current booking data (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data (unused)
      *

src/Form/Service/Condition/BookingEligibilityCondition.php

@@ -26,7 +26,7 @@ use App\Service\ParticipantEligibilityService;
 class BookingEligibilityCondition implements FieldConditionInterface
 {
     public function __construct(
-        private readonly ParticipantEligibilityService $participantEligibilityService
+        private readonly ParticipantEligibilityService $participantEligibilityService,
     ) {
     }
 
@@ -36,7 +36,7 @@ class BookingEligibilityCondition implements FieldConditionInterface
      * Returns true when the participant is INELIGIBLE (should hide service fields).
      * Returns false when the participant is eligible (show normal form fields).
      *
-     * @param BookingDto  $bookingDto       The current booking data
+     * @param BookingDto           $bookingDto       The current booking data
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data for condition evaluation
      *

src/Form/Service/Condition/BulkInsuranceBookingCondition.php

@@ -29,7 +29,7 @@ class BulkInsuranceBookingCondition implements FieldConditionInterface
      * For dependent participants, returns true if the applicant has bulk insurance booking enabled,
      * regardless of whether an insurance is selected (applies to "no insurance" as well).
      *
-     * @param BookingDto  $bookingDto       The current booking data
+     * @param BookingDto           $bookingDto       The current booking data
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data for condition evaluation
      *

src/Form/Service/Condition/CompositeCondition.php

@@ -64,7 +64,7 @@ class CompositeCondition implements FieldConditionInterface
      * evaluation for optimal performance. The evaluation stops as soon as the
      * final result can be determined.
      *
-     * @param BookingDto  $bookingDto       The current booking data (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data for condition evaluation
      *

src/Form/Service/Condition/DateOfBirthProvidedCondition.php

@@ -27,7 +27,7 @@ class DateOfBirthProvidedCondition implements FieldConditionInterface
      * Checks if the participant exists and has a non-null dateOfBirth property.
      * This is a prerequisite for showing age-dependent form fields and services.
      *
-     * @param BookingDto  $bookingDto       The current booking data
+     * @param BookingDto           $bookingDto       The current booking data
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data (unused for this condition)
      *

src/Form/Service/Condition/FieldValueCondition.php

@@ -60,7 +60,7 @@ class FieldValueCondition implements FieldConditionInterface
      * against the expected value using the configured operator. Supports
      * both participant-level fields and booking-level fields.
      *
-     * @param BookingDto  $bookingDto       The current booking data (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data for condition evaluation
      *

src/Form/Service/Condition/MutabilityCondition.php

@@ -21,7 +21,7 @@ class MutabilityCondition implements FieldConditionInterface
     /**
      * Evaluates if the participant's personal data is mutable.
      *
-     * @param BookingDto  $bookingDto       The current booking data (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data (unused)
      *

src/Form/Service/Condition/RentalSelectionCondition.php

@@ -28,7 +28,7 @@ class RentalSelectionCondition implements FieldConditionInterface
      * which would indicate rental services have been selected and body
      * dimensions should be required for proper equipment sizing.
      *
-     * @param BookingDto  $bookingDto       The current booking data (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data for condition evaluation
      *

src/Form/Service/Condition/RoomSelectionCondition.php

@@ -35,7 +35,7 @@ class RoomSelectionCondition implements FieldConditionInterface
      * Checks both submitted form data and participant DTO data to determine
      * if the selected room matches any of the configured room codes.
      *
-     * @param BookingDto  $bookingDto       The current booking data (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data for condition evaluation
      *
@@ -94,7 +94,7 @@ class RoomSelectionCondition implements FieldConditionInterface
     /**
      * Finds a room by ID in the available travel rooms.
      *
-     * @param int                 $roomId     The room ID to find
+     * @param int        $roomId     The room ID to find
      * @param BookingDto $bookingDto The booking DTO containing travel data
      *
      * @return Room|null The found room or null if not found

src/Form/Service/Condition/ServiceSubTypeCondition.php

@@ -52,7 +52,7 @@ class ServiceSubTypeCondition implements FieldConditionInterface
      * property against the expected value(s). Handles both form data and
      * participant DTO data sources.
      *
-     * @param BookingDto  $bookingDto       The current booking data (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data for condition evaluation
      *

src/Form/Service/Condition/SkiPassSelectionCondition.php

@@ -28,7 +28,7 @@ class SkiPassSelectionCondition implements FieldConditionInterface
      * which would indicate a skipass has been selected and rental services
      * should be made available with duration filtering applied.
      *
-     * @param BookingDto  $bookingDto       The current booking data (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data for condition evaluation
      *

src/Form/Service/Contract/FieldOptionsProviderInterface.php

@@ -41,10 +41,10 @@ interface FieldOptionsProviderInterface
      * used when building the form field. These options are merged with any
      * static options defined in the form type.
      *
-     * @param string              $fieldName        The name of the field to configure
+     * @param string     $fieldName        The name of the field to configure
      * @param BookingDto $bookingDto       The current booking data for context (create or edit)
-     * @param int                 $participantIndex The index of the participant being configured
+     * @param int        $participantIndex The index of the participant being configured
-     * @param array               $options          Additional options to customize field behavior
+     * @param array      $options          Additional options to customize field behavior
      *
      * @return array<string, mixed> Symfony form field options, or empty array if field not supported
      */

src/Form/Service/Contract/FieldStateProviderInterface.php

@@ -38,7 +38,7 @@ interface FieldStateProviderInterface
      * condition independently to allow early field exclusion during form building.
      *
      * @param string               $fieldName        The name of the field to evaluate
-     * @param BookingDto  $bookingDto       The current booking data for context (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data for context (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data for condition evaluation
      *
@@ -65,7 +65,7 @@ interface FieldStateProviderInterface
      * - 'attr' => ['class' => 'conditional-field'] - Add CSS classes
      *
      * @param string               $fieldName        The name of the field to evaluate
-     * @param BookingDto  $bookingDto       The current booking data for context (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data for context (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data (may include partial submissions)
      *
@@ -110,7 +110,7 @@ interface FieldStateProviderInterface
      * when multiple field states need to be determined simultaneously. It's
      * particularly useful during form building and bulk state updates.
      *
-     * @param BookingDto  $bookingDto       The current booking data for context (create or edit)
+     * @param BookingDto           $bookingDto       The current booking data for context (create or edit)
      * @param int                  $participantIndex The index of the participant being evaluated
      * @param array<string, mixed> $formData         Current form data for condition evaluation
      *

src/Form/Service/Contract/ParticipantFieldHandlerInterface.php

@@ -32,7 +32,7 @@ interface ParticipantFieldHandlerInterface
      * Processes the participant field data from submitted form data and updates the DTO.
      *
      * @param array<string, mixed> $submittedData    The submitted participant form data
-     * @param BookingDto  $bookingDto       The booking DTO to update (create or edit)
+     * @param BookingDto           $bookingDto       The booking DTO to update (create or edit)
      * @param int                  $participantIndex The participant index being processed
      */
     public function processField(array $submittedData, BookingDto $bookingDto, int $participantIndex): void;
@@ -54,7 +54,7 @@ interface ParticipantFieldHandlerInterface
      * to enable/disable/hide fields based on the handler's processing results.
      *
      * @param array<string, mixed> $submittedData    The submitted participant form data
-     * @param BookingDto  $bookingDto       The booking DTO (potentially modified by processing)
+     * @param BookingDto           $bookingDto       The booking DTO (potentially modified by processing)
      * @param int                  $participantIndex The participant index being processed
      *
      * @return array<string, array<string, mixed>> Field state modifications indexed by field name

src/Form/Service/EditFieldStateProvider.php

@@ -11,7 +11,6 @@ use App\Form\Service\Condition\ApplicantCondition;
 use App\Form\Service\Condition\CompositeCondition;
 use App\Form\Service\Condition\DateOfBirthProvidedCondition;
 use App\Form\Service\Condition\FieldValueCondition;
-use App\Form\Service\Condition\InsuranceMutabilityCondition;
 use App\Form\Service\Condition\MutabilityCondition;
 use App\Form\Service\Condition\PickupsMutabilityCondition;
 use App\Form\Service\Condition\RentalSelectionCondition;

src/Form/Service/ParticipantAdditionalServicesFieldHandler.php

@@ -85,8 +85,7 @@ class ParticipantAdditionalServicesFieldHandler extends AbstractParticipantField
      * 5. Updates participant with filtered valid selections
      *
      * @param array<string, mixed> $submittedData    The submitted participant form data
-     * @param string               $mode             The booking mode (BookingDto::MODE_CREATE or MODE_EDIT)
+     * @param BookingDto           $bookingDto       The booking DTO to update (create or edit)
-     * @param BookingDto  $bookingDto       The booking DTO to update (create or edit)
      * @param int                  $participantIndex The index of the participant being processed
      */
     public function processField(array $submittedData, BookingDto $bookingDto, int $participantIndex): void
@@ -122,10 +121,10 @@ class ParticipantAdditionalServicesFieldHandler extends AbstractParticipantField
      * and the participant's age constraints. Services that are no longer available
      * or appropriate for the participant's age are filtered out.
      *
-     * @param array               $selectedServices  List of currently selected services
+     * @param array      $selectedServices  List of currently selected services
-     * @param array               $availableServices List of all available additional services
+     * @param array      $availableServices List of all available additional services
      * @param BookingDto $bookingDto        The booking DTO for context
-     * @param int                 $participantIndex  The participant index for age evaluation
+     * @param int        $participantIndex  The participant index for age evaluation
      *
      * @return array Filtered array of valid service selections
      */
@@ -156,10 +155,10 @@ class ParticipantAdditionalServicesFieldHandler extends AbstractParticipantField
      * This method checks if a selected service exists in the available services
      * and meets the age constraints for the current participant.
      *
-     * @param mixed               $selectedService   The selected service to validate
+     * @param mixed      $selectedService   The selected service to validate
-     * @param array               $availableServices Array of available services
+     * @param array      $availableServices Array of available services
      * @param BookingDto $bookingDto        The booking DTO for context
-     * @param int                 $participantIndex  The participant index for age evaluation
+     * @param int        $participantIndex  The participant index for age evaluation
      *
      * @return bool True if the service is valid for the participant, false otherwise
      */

src/Form/Service/ParticipantBulkInsuranceFieldHandler.php

@@ -56,7 +56,7 @@ class ParticipantBulkInsuranceFieldHandler extends AbstractParticipantFieldHandl
      * to dependent participants is handled by BookingDataProcessor during API submission.
      *
      * @param array<string, mixed> $submittedData    The submitted participant form data
-     * @param BookingDto  $bookingDto       The booking DTO to update
+     * @param BookingDto           $bookingDto       The booking DTO to update
      * @param int                  $participantIndex The index of the participant (must be 0)
      */
     public function processField(array $submittedData, BookingDto $bookingDto, int $participantIndex): void

src/Form/Service/ParticipantCoursesFieldHandler.php

@@ -78,8 +78,7 @@ class ParticipantCoursesFieldHandler extends AbstractParticipantFieldHandler
      * no longer appropriate for the participant's age are automatically removed.
      *
      * @param array<string, mixed> $submittedData    The submitted participant form data
-     * @param string               $mode             The booking mode (BookingDto::MODE_CREATE or MODE_EDIT)
+     * @param BookingDto           $bookingDto       The booking DTO to update (create or edit)
-     * @param BookingDto  $bookingDto       The booking DTO to update (create or edit)
      * @param int                  $participantIndex The index of the participant being processed
      */
     public function processField(array $submittedData, BookingDto $bookingDto, int $participantIndex): void
@@ -111,10 +110,10 @@ class ParticipantCoursesFieldHandler extends AbstractParticipantFieldHandler
     /**
      * Filters course selections to keep only those valid for the participant's age.
      *
-     * @param array               $selectedServices  List of currently selected courses
+     * @param array      $selectedServices  List of currently selected courses
-     * @param array               $availableServices List of all available courses
+     * @param array      $availableServices List of all available courses
      * @param BookingDto $bookingDto        The booking DTO for context
-     * @param int                 $participantIndex  The participant index for age evaluation
+     * @param int        $participantIndex  The participant index for age evaluation
      *
      * @return array Filtered array of valid course selections
      */
@@ -142,10 +141,10 @@ class ParticipantCoursesFieldHandler extends AbstractParticipantFieldHandler
     /**
      * Validates if a selected course is still valid for the participant.
      *
-     * @param mixed               $selectedService   The selected course to validate
+     * @param mixed      $selectedService   The selected course to validate
-     * @param array               $availableServices Array of available courses
+     * @param array      $availableServices Array of available courses
      * @param BookingDto $bookingDto        The booking DTO for context
-     * @param int                 $participantIndex  The participant index for age evaluation
+     * @param int        $participantIndex  The participant index for age evaluation
      *
      * @return bool True if the course is valid for the participant, false otherwise
      */

src/Form/Service/ParticipantEmailFieldHandler.php

@@ -0,0 +1,138 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Form\Service;
+
+use App\Form\Model\BookingDto;
+use App\Form\Service\Abstract\AbstractParticipantFieldHandler;
+
+/**
+ * Handles email uniqueness validation for booking participants.
+ *
+ * This handler provides real-time feedback during form refresh when an adult
+ * participant enters an email address that is already used by another adult
+ * participant in the same booking. Children (under 16) are exempt from this
+ * validation and can share email addresses with adults or other children.
+ *
+ * The handler adds warning notifications during the HTMX refresh cycle,
+ * providing immediate user feedback without blocking form submission.
+ * Hard validation is enforced via BookingDto::validateEmailUniqueness()
+ * when the user attempts to proceed to the next step.
+ */
+class ParticipantEmailFieldHandler extends AbstractParticipantFieldHandler
+{
+    /**
+     * Returns the form field name this handler processes.
+     *
+     * @return string The field name 'email'
+     */
+    public function getFieldName(): string
+    {
+        return 'email';
+    }
+
+    /**
+     * Returns the field dependencies for proper processing order.
+     *
+     * Email validation has no dependencies on other fields.
+     *
+     * @return string[] Empty array (no dependencies)
+     */
+    public function getDependencies(): array
+    {
+        return [];
+    }
+
+    /**
+     * Determines if this handler should process the field based on submitted data.
+     *
+     * Email validation should always run when the email field is present in
+     * the submitted data, regardless of booking mode or participant index.
+     *
+     * @param array<string, mixed> $submittedData    The submitted participant form data
+     * @param string               $mode             The booking mode (BookingDto::MODE_CREATE or MODE_EDIT)
+     * @param int                  $participantIndex The index of the participant being processed
+     *
+     * @return bool True if email field exists in submitted data
+     */
+    public function shouldProcess(array $submittedData, string $mode, int $participantIndex): bool
+    {
+        return array_key_exists($this->getFieldName(), $submittedData);
+    }
+
+    /**
+     * Processes the email field for a specific participant.
+     *
+     * This method checks if the participant's email address is already used by
+     * another adult participant in the same booking. If a duplicate is found,
+     * a warning notification is added to the participant for display as a toast.
+     *
+     * Validation rules:
+     * - Children (under 16 at current date) are exempt from uniqueness validation
+     * - Null or empty emails are skipped (handled by Symfony's @Assert\Email)
+     * - Only duplicates with other adult participants trigger warnings
+     *
+     * @param array<string, mixed> $submittedData    The submitted participant form data
+     * @param BookingDto           $bookingDto       The booking DTO to update (create or edit)
+     * @param int                  $participantIndex The index of the participant being processed
+     */
+    public function processField(array $submittedData, BookingDto $bookingDto, int $participantIndex): void
+    {
+        // Safely get the participant object, returning early if not found
+        $participant = $this->getParticipant($bookingDto, $participantIndex);
+        if (null === $participant) {
+            return;
+        }
+
+        // Skip validation for children (they can share email addresses)
+        if (true === $participant->isChild()) {
+            return;
+        }
+
+        // Get the email value from submitted data (field handlers run in PRE_SUBMIT, before form binding)
+        $email = $submittedData[$this->getFieldName()] ?? null;
+
+        // Skip if email is null or empty (handled by other validators)
+        if (null === $email || '' === trim($email)) {
+            return;
+        }
+
+        // Normalize email for comparison (case-insensitive)
+        $normalizedEmail = strtolower(trim($email));
+
+        // Check for duplicate emails among other adult participants
+        $hasDuplicate = false;
+        foreach ($bookingDto->participants as $index => $otherParticipant) {
+            // Skip comparing with self
+            if ($index === $participantIndex) {
+                continue;
+            }
+
+            // Skip if other participant is a child (children can share emails)
+            if (true === $otherParticipant->isChild()) {
+                continue;
+            }
+
+            // Skip if other participant has no email
+            if (null === $otherParticipant->email || '' === trim($otherParticipant->email)) {
+                continue;
+            }
+
+            // Compare normalized emails
+            $otherNormalizedEmail = strtolower(trim($otherParticipant->email));
+            if ($normalizedEmail === $otherNormalizedEmail) {
+                $hasDuplicate = true;
+                break;
+            }
+        }
+
+        // Add warning notification if duplicate found
+        if (true === $hasDuplicate) {
+            $participant->addNotification(
+                'warning',
+                'Diese E-Mail Adresse wird bereits von einem anderen erwachsenen Teilnehmer verwendet'
+            );
+        }
+    }
+}

src/Form/Service/ParticipantLicensePlateFieldHandler.php

@@ -70,7 +70,7 @@ class ParticipantLicensePlateFieldHandler extends AbstractParticipantFieldHandle
      * the license plate is automatically cleared to maintain data consistency.
      *
      * @param array<string, mixed> $submittedData    The submitted participant form data
-     * @param BookingDto  $bookingDto       The booking DTO to update (create or edit)
+     * @param BookingDto           $bookingDto       The booking DTO to update (create or edit)
      * @param int                  $participantIndex The index of the participant being processed
      */
     public function processField(array $submittedData, BookingDto $bookingDto, int $participantIndex): void

src/Form/Service/ParticipantRemarksRoomFieldHandler.php

@@ -41,7 +41,7 @@ class ParticipantRemarksRoomFieldHandler extends AbstractParticipantFieldHandler
      * the normalization of empty strings to null values.
      *
      * @param array<string, mixed> $submittedData    The submitted participant form data
-     * @param BookingDto  $bookingDto       The booking DTO to update (create or edit)
+     * @param BookingDto           $bookingDto       The booking DTO to update (create or edit)
      * @param int                  $participantIndex The index of the participant being processed
      */
     public function processField(array $submittedData, BookingDto $bookingDto, int $participantIndex): void

src/Form/Service/ParticipantRentalInsuranceFieldHandler.php

@@ -75,8 +75,7 @@ class ParticipantRentalInsuranceFieldHandler extends AbstractParticipantFieldHan
      * is no longer appropriate for the participant's age, it is automatically cleared.
      *
      * @param array<string, mixed> $submittedData    The submitted participant form data
-     * @param string               $mode             The booking mode (BookingDto::MODE_CREATE or MODE_EDIT)
+     * @param BookingDto           $bookingDto       The booking DTO to update (create or edit)
-     * @param BookingDto  $bookingDto       The booking DTO to update (create or edit)
      * @param int                  $participantIndex The index of the participant being processed
      */
     public function processField(array $submittedData, BookingDto $bookingDto, int $participantIndex): void

src/Form/Service/ParticipantSkiPassFieldHandler.php

@@ -79,9 +79,9 @@ class ParticipantSkiPassFieldHandler extends AbstractParticipantFieldHandler
      * selection. If the skipass is no longer appropriate for the participant's
      * age or exceeds the travel date range, it is automatically cleared.
      *
-     * @param array<string, mixed> $submittedData The submitted participant form data
+     * @param array<string, mixed> $submittedData    The submitted participant form data
-     * @param BookingDto $bookingDto The booking DTO to update (create or edit)
+     * @param BookingDto           $bookingDto       The booking DTO to update (create or edit)
-     * @param int $participantIndex The index of the participant being processed
+     * @param int                  $participantIndex The index of the participant being processed
      */
     public function processField(array $submittedData, BookingDto $bookingDto, int $participantIndex): void
     {
@@ -116,10 +116,10 @@ class ParticipantSkiPassFieldHandler extends AbstractParticipantFieldHandler
      * This method checks both age constraints (via birth year ranges) and
      * date constraints (skipass dates must be within travel dates).
      *
-     * @param mixed               $selectedService   The selected skipass to validate
+     * @param mixed      $selectedService   The selected skipass to validate
-     * @param array               $availableServices Array of available skipasses
+     * @param array      $availableServices Array of available skipasses
      * @param BookingDto $bookingDto        The booking DTO for context
-     * @param int                 $participantIndex  The participant index for age evaluation
+     * @param int        $participantIndex  The participant index for age evaluation
      *
      * @return bool True if the skipass is valid for the participant, false otherwise
      */

src/Form/Service/ServiceAgeEvaluator.php

@@ -39,9 +39,9 @@ class ServiceAgeEvaluator
      * that services are appropriately filtered based on the participant's
      * age at the time of travel, not their current age.
      *
-     * @param Service             $service          The service to evaluate
+     * @param Service    $service          The service to evaluate
      * @param BookingDto $bookingDto       The booking containing participant data
-     * @param int                 $participantIndex The index of the participant to evaluate
+     * @param int        $participantIndex The index of the participant to evaluate
      *
      * @return bool True if the service is available for the participant
      */

src/Service/BookingFingerprintService.php

@@ -117,5 +117,4 @@ class BookingFingerprintService
 
         return $bookingDto->originalFingerprint !== $currentFingerprint;
     }
-
 }

src/Service/BookingService.php

@@ -149,7 +149,7 @@ class BookingService
      * Persists the current booking state to the session for retrieval
      * across multiple HTTP requests during the booking flow.
      *
-     * @param Request          $request          The HTTP request with session
+     * @param Request    $request          The HTTP request with session
      * @param BookingDto $bookingCreateDto The booking DTO to persist
      */
     public function saveBookingCreateDto(Request $request, BookingDto $bookingCreateDto): void
@@ -416,7 +416,7 @@ class BookingService
      * Compares the current room selection state with a baseline snapshot
      * to detect changes that would require participant reassignment.
      *
-     * @param array            $oldSnapshot The baseline room selection snapshot
+     * @param array      $oldSnapshot The baseline room selection snapshot
      * @param BookingDto $newDto      The current booking DTO
      *
      * @return bool True if room selections have changed, false otherwise

src/Service/InsuranceService.php

@@ -59,7 +59,7 @@ class InsuranceService
         array $insurances,
         ParticipantDto $participant,
         BookingDto $booking,
-        float $travelPrice
+        float $travelPrice,
     ): array {
         $travelStartDate = $booking->travel->dateFrom;
         $travelEndDate = $booking->travel->dateTo;
@@ -108,7 +108,7 @@ class InsuranceService
         Insurance $currentInsurance,
         ParticipantDto $participant,
         BookingDto $booking,
-        float $travelPrice
+        float $travelPrice,
     ): ?Insurance {
         // Group insurances of the same type
         $sameTypeInsurances = $this->filterByType($availableInsurances, $currentInsurance);
@@ -127,10 +127,10 @@ class InsuranceService
      * (subType + familyInsurance) to all participants, but selects the appropriate price tier
      * based on each participant's individual travel price.
      *
-     * @param array<Insurance>     $availableInsurances All available insurances
+     * @param array<Insurance>  $availableInsurances All available insurances
-     * @param Insurance            $selectedInsurance   The insurance selected by the applicant
+     * @param Insurance         $selectedInsurance   The insurance selected by the applicant
-     * @param BookingDto           $booking             The booking with all participants
+     * @param BookingDto        $booking             The booking with all participants
-     * @param array<int, float>    $participantPrices   Map of participant index to travel price (excluding insurance)
+     * @param array<int, float> $participantPrices   Map of participant index to travel price (excluding insurance)
      *
      * @return array<int, Insurance|null> Array indexed by participant index with assigned insurances
      */
@@ -138,7 +138,7 @@ class InsuranceService
         array $availableInsurances,
         Insurance $selectedInsurance,
         BookingDto $booking,
-        array $participantPrices
+        array $participantPrices,
     ): array {
         $assignments = [];
 
@@ -280,7 +280,7 @@ class InsuranceService
     private function checkAgeConstraints(
         Insurance $insurance,
         ParticipantDto $participant,
-        \DateTimeImmutable $travelStartDate
+        \DateTimeImmutable $travelStartDate,
     ): bool {
         $participantAge = $participant->getAge($travelStartDate);
 
@@ -305,7 +305,7 @@ class InsuranceService
     private function checkTravelDateConstraints(
         Insurance $insurance,
         \DateTimeImmutable $travelStartDate,
-        \DateTimeImmutable $travelEndDate
+        \DateTimeImmutable $travelEndDate,
     ): bool {
         // Check travel start date
         if (null !== $insurance->travelDateFrom && $travelStartDate < $insurance->travelDateFrom) {
@@ -368,5 +368,4 @@ class InsuranceService
 
         return true;
     }
-
 }

src/Service/ParticipantEligibilityService.php

@@ -32,7 +32,7 @@ class ParticipantEligibilityService
      * Results are cached per request to avoid redundant calculations.
      *
      * @param BookingDto $bookingDto       The current booking data
-     * @param int                 $participantIndex The index of the participant being evaluated
+     * @param int        $participantIndex The index of the participant being evaluated
      *
      * @return bool True if participant is eligible (has available skipasses)
      */

templates/booking/_participant_card.html.twig

@@ -1,60 +1,77 @@
 {# Compact participant card with name, room, price, and edit button #}
 {% set isCanceled = isCanceled|default(false) %}
 {% set hasErrors = hasErrors|default(false) %}
+{% set errorMessages = errorMessages|default([]) %}
 {% set mode = mode|default('create') %}
 
 <div id="participant-card-{{ index }}"
-     class="border rounded p-4 flex justify-between items-center
+     class="border rounded p-4
      {{ isCanceled ? 'border-gray-400 bg-gray-50' : (hasErrors ? 'border-red-500 bg-red-50' : '') }}">
-    <div>
+    <div class="flex justify-between items-start">
-        <div class="flex items-center gap-2">
+        <div class="flex-1">
-            <h3 class="font-semibold {{ hasErrors ? 'text-red-800' : (isCanceled ? 'text-gray-600' : '') }}" {{ qa_attribute('participant-name', index) }}>
+            <div class="flex items-center gap-2">
-                {{ cardData.name }}
+                <h3 class="font-semibold {{ hasErrors ? 'text-red-800' : (isCanceled ? 'text-gray-600' : '') }}" {{ qa_attribute('participant-name', index) }}>
-            </h3>
+                    {{ cardData.name }}
-            {% if isCanceled %}
+                </h3>
-                <span class="inline-flex items-center px-2 py-0.5 rounded text-xs font-medium bg-gray-700 text-white" {{ qa_attribute('participant-canceled', index) }}>
+                {% if isCanceled %}
-                    storniert
+                    <span class="inline-flex items-center px-2 py-0.5 rounded text-xs font-medium bg-gray-700 text-white" {{ qa_attribute('participant-canceled', index) }}>
-                </span>
+                        storniert
-            {% elseif hasErrors %}
+                    </span>
-                <span class="inline-flex items-center px-2 py-0.5 rounded text-xs font-medium bg-red-100 text-red-800" {{ qa_attribute('participant-incomplete', index) }}>
+                {% elseif hasErrors %}
-                    <svg class="w-3 h-3 mr-1" fill="currentColor" viewBox="0 0 20 20">
+                    <span class="inline-flex items-center px-2 py-0.5 rounded text-xs font-medium bg-red-100 text-red-800" {{ qa_attribute('participant-incomplete', index) }}>
-                        <path fill-rule="evenodd" d="M18 10a8 8 0 11-16 0 8 8 0 0116 0zm-7 4a1 1 0 11-2 0 1 1 0 012 0zm-1-9a1 1 0 00-1 1v4a1 1 0 102 0V6a1 1 0 00-1-1z" clip-rule="evenodd"></path>
+                        <svg class="w-3 h-3 mr-1" fill="currentColor" viewBox="0 0 20 20">
-                    </svg>
+                            <path fill-rule="evenodd" d="M18 10a8 8 0 11-16 0 8 8 0 0116 0zm-7 4a1 1 0 11-2 0 1 1 0 012 0zm-1-9a1 1 0 00-1 1v4a1 1 0 102 0V6a1 1 0 00-1-1z" clip-rule="evenodd"></path>
-                    Unvollständig
+                        </svg>
-                </span>
+                        Unvollständig
+                    </span>
+                {% endif %}
+            </div>
+            <p class="text-sm text-gray-600" {{ qa_attribute('participant-room-name', index) }}>{{ cardData.roomName }}</p>
+
+            {# Display specific error messages #}
+            {% if hasErrors and errorMessages|length > 0 %}
+                <div class="mt-2 space-y-1" {{ qa_attribute('participant-errors', index) }}>
+                    {% for errorMessage in errorMessages %}
+                        <p class="text-sm text-red-700">
+                            <svg class="w-4 h-4 inline mr-1" fill="currentColor" viewBox="0 0 20 20">
+                                <path fill-rule="evenodd" d="M18 10a8 8 0 11-16 0 8 8 0 0116 0zm-7 4a1 1 0 11-2 0 1 1 0 012 0zm-1-9a1 1 0 00-1 1v4a1 1 0 102 0V6a1 1 0 00-1-1z" clip-rule="evenodd"></path>
+                            </svg>
+                            {{ errorMessage }}
+                        </p>
+                    {% endfor %}
+                </div>
             {% endif %}
         </div>
-        <p class="text-sm text-gray-600" {{ qa_attribute('participant-room-name', index) }}>{{ cardData.roomName }}</p>
+        <div class="flex items-center gap-4">
-    </div>
+            <span class="font-medium {{ isCanceled ? 'text-gray-500' : '' }}" {{ qa_attribute('participant-price', index) }}>{{ cardData.price }}</span>
-    <div class="flex items-center gap-4">
+            {% if isCanceled %}
-        <span class="font-medium {{ isCanceled ? 'text-gray-500' : '' }}" {{ qa_attribute('participant-price', index) }}>{{ cardData.price }}</span>
-        {% if isCanceled %}
-            <button type="button"
-                    class="button bg-button bg-button--secondary opacity-50 cursor-not-allowed"
-                    disabled
-                    title="Stornierte Teilnehmer können nicht bearbeitet werden">
-                Bearbeiten
-            </button>
-        {% else %}
-            {% if mode == 'edit' %}
                 <button type="button"
-                        class="button bg-button {{ hasErrors ? 'bg-button--primary' : 'bg-button--secondary' }}"
+                        class="button bg-button bg-button--secondary opacity-50 cursor-not-allowed"
-                        hx-get="{{ path('app_booking_edit_participant', {id: bookingId, index: index}) }}"
+                        disabled
-                        hx-target="#main-content"
+                        title="Stornierte Teilnehmer können nicht bearbeitet werden">
-                        hx-swap="innerHTML"
-                        {{ qa_attribute('btn-edit-participant', index) }}>
                     Bearbeiten
                 </button>
             {% else %}
-                <button type="button"
+                {% if mode == 'edit' %}
-                        class="button bg-button {{ hasErrors ? 'bg-button--primary' : 'bg-button--secondary' }}"
+                    <button type="button"
-                        hx-get="{{ path('app_booking_create_step_2_participant', {index: index}) }}"
+                            class="button bg-button {{ hasErrors ? 'bg-button--primary' : 'bg-button--secondary' }}"
-                        hx-target="#main-content"
+                            hx-get="{{ path('app_booking_edit_participant', {id: bookingId, index: index}) }}"
-                        hx-swap="innerHTML"
+                            hx-target="#main-content"
-                        {{ qa_attribute('btn-edit-participant', index) }}>
+                            hx-swap="innerHTML"
-                    Bearbeiten
+                            {{ qa_attribute('btn-edit-participant', index) }}>
-                </button>
+                        Bearbeiten
+                    </button>
+                {% else %}
+                    <button type="button"
+                            class="button bg-button {{ hasErrors ? 'bg-button--primary' : 'bg-button--secondary' }}"
+                            hx-get="{{ path('app_booking_create_step_2_participant', {index: index}) }}"
+                            hx-target="#main-content"
+                            hx-swap="innerHTML"
+                            {{ qa_attribute('btn-edit-participant', index) }}>
+                        Bearbeiten
+                    </button>
+                {% endif %}
             {% endif %}
-        {% endif %}
+        </div>
     </div>
 </div>

templates/booking/_participant_form.html.twig

@@ -60,7 +60,14 @@
 
             {# Contact information #}
             <div class="grid grid-cols-2 gap-4">
-                {{ form_row(form.email) }}
+                {{ form_row(form.email, {
+                    'attr': {
+                        'hx-trigger': 'change',
+                        'hx-post': path(refreshRouteName, refreshRouteParams|default({index: participantIndex})),
+                        'hx-target': '#main-content',
+                        'hx-swap': 'innerHTML'
+                    }
+                }) }}
                 {{ form_row(form.mobile) }}
             </div>
 

templates/booking/create/step_2.html.twig

@@ -2,7 +2,6 @@
 
 {% block content %}
     {% include '_partials/_flashes.html.twig' %}
-    <div {{ stimulus_controller('toast') }}></div>
     <h1>Neue Buchung</h1>
 
     <div class="grid grid-cols-3 gap-8">
@@ -37,11 +36,13 @@
             <div id="participant-cards-grid" class="space-y-4">
                 {% for cardData in cardsData %}
                     {% set hasErrors = loop.index0 in participantErrors|default([]) %}
+                    {% set errorMessages = participantErrorMessages[loop.index0]|default([]) %}
                     {% include 'booking/_participant_card.html.twig' with {
                         'cardData': cardData,
                         'index': loop.index0,
                         'mode': 'create',
-                        'hasErrors': hasErrors
+                        'hasErrors': hasErrors,
+                        'errorMessages': errorMessages
                     } %}
                 {% endfor %}
             </div>

templates/booking/edit/index.html.twig

@@ -2,7 +2,6 @@
 
 {% block content %}
     {% include '_partials/_flashes.html.twig' %}
-    <div {{ stimulus_controller('toast') }}></div>
 
     {# Header with reload button #}
     <div class="flex justify-between items-center pb-8">
@@ -62,12 +61,14 @@
                     {% for participant in bookingDto.participants %}
                         {% set isCanceled = (bookingData.participantsStatus[loop.index0] ?? null) == 'S' %}
                         {% set hasErrors = loop.index0 in participantErrors|default([]) %}
+                        {% set errorMessages = participantErrorMessages[loop.index0]|default([]) %}
                         {% include 'booking/_participant_card.html.twig' with {
                             'cardData': cardsData[loop.index0],
                             'index': loop.index0,
                             'mode': 'edit',
                             'isCanceled': isCanceled,
                             'hasErrors': hasErrors,
+                            'errorMessages': errorMessages,
                             'bookingId': bookingData.id
                         } %}
                     {% endfor %}

templates/layout.html.twig

@@ -1,6 +1,9 @@
 {% extends 'base.html.twig' %}
 
 {% block body %}
+    {# Global toast controller - persists across all HTMX swaps and page navigations #}
+    <div {{ stimulus_controller('toast') }}></div>
+
     <div class="{{ html_classes('pb-8', { 'pt-24': is_granted('ROLE_USER') }) }}" {{ stimulus_controller('loading', [], { 'hidden': 'invisible' }) }}>
         <div class="fixed inset-x-0 top-0 z-20">
             <div class="max-w-screen-xl mx-auto flex items-center justify-between bg-primary-dark text-white">

tests/Form/Model/BookingDtoTest.php

@@ -0,0 +1,314 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Form\Model;
+
+use App\BusProNet\Model\Travel;
+use App\Form\Model\BookingDto;
+use App\Form\Model\ParticipantDto;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Validator\Validation;
+use Symfony\Component\Validator\Validator\ValidatorInterface;
+
+class BookingDtoTest extends TestCase
+{
+    private ValidatorInterface $validator;
+
+    protected function setUp(): void
+    {
+        $this->validator = Validation::createValidatorBuilder()
+            ->enableAttributeMapping()
+            ->getValidator();
+    }
+
+    public function testEmailUniquenessValidationWithUniqueAdultEmailsPasses(): void
+    {
+        $bookingDto = $this->createBookingDtoWithParticipants([
+            $this->createAdultParticipant('[email protected]'),
+            $this->createAdultParticipant('[email protected]'),
+            $this->createAdultParticipant('[email protected]'),
+        ]);
+
+        $violations = $this->validator->validate($bookingDto, null, ['booking_create_step_2']);
+
+        $this->assertCount(0, $violations);
+    }
+
+    public function testEmailUniquenessValidationWithTwoAdultsSameEmailFails(): void
+    {
+        $bookingDto = $this->createBookingDtoWithParticipants([
+            $this->createAdultParticipant('[email protected]'),
+            $this->createAdultParticipant('[email protected]'),
+        ]);
+
+        $violations = $this->validator->validate($bookingDto, null, ['booking_create_step_2']);
+
+        // Should have 2 violations (one for each adult with duplicate email)
+        $this->assertCount(2, $violations);
+
+        // Check that violations are at the correct paths
+        $violationPaths = [];
+        foreach ($violations as $violation) {
+            $violationPaths[] = $violation->getPropertyPath();
+        }
+
+        $this->assertContains('participants[0].email', $violationPaths);
+        $this->assertContains('participants[1].email', $violationPaths);
+
+        // Check violation message
+        $this->assertSame(
+            'Diese E-Mail Adresse wird bereits von einem anderen erwachsenen Teilnehmer verwendet',
+            $violations->get(0)->getMessage()
+        );
+    }
+
+    public function testEmailUniquenessValidationWithThreeAdultsSameEmailFails(): void
+    {
+        $bookingDto = $this->createBookingDtoWithParticipants([
+            $this->createAdultParticipant('[email protected]'),
+            $this->createAdultParticipant('[email protected]'),
+            $this->createAdultParticipant('[email protected]'),
+        ]);
+
+        $violations = $this->validator->validate($bookingDto, null, ['booking_create_step_2']);
+
+        // Should have 3 violations (one for each adult with duplicate email)
+        $this->assertCount(3, $violations);
+    }
+
+    public function testEmailUniquenessValidationWithAdultAndChildSameEmailPasses(): void
+    {
+        $bookingDto = $this->createBookingDtoWithParticipants([
+            $this->createAdultParticipant('[email protected]'),
+            $this->createChildParticipant('[email protected]'),
+        ]);
+
+        $violations = $this->validator->validate($bookingDto, null, ['booking_create_step_2']);
+
+        $this->assertCount(0, $violations);
+    }
+
+    public function testEmailUniquenessValidationWithTwoChildrenSameEmailPasses(): void
+    {
+        $bookingDto = $this->createBookingDtoWithParticipants([
+            $this->createChildParticipant('[email protected]'),
+            $this->createChildParticipant('[email protected]'),
+        ]);
+
+        $violations = $this->validator->validate($bookingDto, null, ['booking_create_step_2']);
+
+        $this->assertCount(0, $violations);
+    }
+
+    public function testEmailUniquenessValidationWithNullBirthDateTreatedAsAdult(): void
+    {
+        $participant1 = new ParticipantDto();
+        $participant1->firstName = 'John';
+        $participant1->lastName = 'Doe';
+        $participant1->dateOfBirth = null; // Unknown age - treated as adult
+        $participant1->email = '[email protected]';
+
+        $participant2 = $this->createAdultParticipant('[email protected]');
+
+        $bookingDto = $this->createBookingDtoWithParticipants([$participant1, $participant2]);
+
+        $violations = $this->validator->validate($bookingDto, null, ['booking_create_step_2']);
+
+        // Should have violations for duplicate emails (both treated as adults)
+        $emailViolations = [];
+        foreach ($violations as $violation) {
+            if (str_contains($violation->getPropertyPath(), '.email')) {
+                $emailViolations[] = $violation;
+            }
+        }
+
+        $this->assertCount(2, $emailViolations);
+    }
+
+    public function testEmailUniquenessValidationWithNullEmailsSkipped(): void
+    {
+        // Create participants with explicitly null emails (not using createAdultParticipant helper)
+        $participant1 = $this->createValidParticipant(new \DateTimeImmutable('1990-01-01'), '[email protected]');
+        $participant1->email = null; // Set to null explicitly
+
+        $participant2 = $this->createValidParticipant(new \DateTimeImmutable('1990-01-01'), '[email protected]');
+        $participant2->email = null; // Set to null explicitly
+
+        $bookingDto = $this->createBookingDtoWithParticipants([$participant1, $participant2]);
+
+        $violations = $this->validator->validate($bookingDto, null, ['booking_create_step_2']);
+
+        // Should not have email uniqueness violations (other validations may fail for null email)
+        foreach ($violations as $violation) {
+            $this->assertStringNotContainsString(
+                'wird bereits von einem anderen erwachsenen Teilnehmer verwendet',
+                $violation->getMessage()
+            );
+        }
+    }
+
+    public function testEmailUniquenessValidationWithEmptyEmailsSkipped(): void
+    {
+        $participant1 = $this->createAdultParticipant('');
+        $participant2 = $this->createAdultParticipant('');
+
+        $bookingDto = $this->createBookingDtoWithParticipants([$participant1, $participant2]);
+
+        $violations = $this->validator->validate($bookingDto, null, ['booking_create_step_2']);
+
+        // Should not have email uniqueness violations (other validations may fail)
+        foreach ($violations as $violation) {
+            $this->assertStringNotContainsString(
+                'wird bereits von einem anderen erwachsenen Teilnehmer verwendet',
+                $violation->getMessage()
+            );
+        }
+    }
+
+    public function testEmailUniquenessValidationCaseInsensitive(): void
+    {
+        $bookingDto = $this->createBookingDtoWithParticipants([
+            $this->createAdultParticipant('[email protected]'),
+            $this->createAdultParticipant('[email protected]'),
+        ]);
+
+        $violations = $this->validator->validate($bookingDto, null, ['booking_create_step_2']);
+
+        // Should have 2 violations (case-insensitive comparison)
+        $emailViolations = [];
+        foreach ($violations as $violation) {
+            if (str_contains($violation->getPropertyPath(), '.email')) {
+                $emailViolations[] = $violation;
+            }
+        }
+
+        $this->assertCount(2, $emailViolations);
+    }
+
+    public function testEmailUniquenessValidationWithWhitespaceNormalization(): void
+    {
+        // Create participants with trimmed emails to avoid @Assert\Email strict mode validation failures
+        $participant1 = $this->createValidParticipant(new \DateTimeImmutable('1990-01-01'), '[email protected]');
+        $participant1->email = '  [email protected]  '; // Set whitespace email explicitly after creation
+
+        $participant2 = $this->createAdultParticipant('[email protected]');
+
+        $bookingDto = $this->createBookingDtoWithParticipants([$participant1, $participant2]);
+
+        $violations = $this->validator->validate($bookingDto, null, ['booking_create_step_2']);
+
+        // Should have 2 violations for email uniqueness (whitespace trimmed during comparison)
+        // Note: May also have email format violation for the whitespace email
+        $uniquenessViolations = [];
+        foreach ($violations as $violation) {
+            if (str_contains($violation->getMessage(), 'wird bereits von einem anderen erwachsenen Teilnehmer verwendet')) {
+                $uniquenessViolations[] = $violation;
+            }
+        }
+
+        $this->assertCount(2, $uniquenessViolations);
+    }
+
+    public function testEmailUniquenessValidationInEditMode(): void
+    {
+        $bookingDto = $this->createBookingDtoWithParticipants([
+            $this->createAdultParticipant('[email protected]'),
+            $this->createAdultParticipant('[email protected]'),
+        ]);
+
+        $violations = $this->validator->validate($bookingDto, null, ['booking_edit']);
+
+        // Should have 2 violations in edit mode as well
+        $this->assertCount(2, $violations);
+    }
+
+    public function testEmailUniquenessValidationMixedScenario(): void
+    {
+        $bookingDto = $this->createBookingDtoWithParticipants([
+            $this->createAdultParticipant('[email protected]'),   // Unique - OK
+            $this->createAdultParticipant('[email protected]'), // Duplicate - ERROR
+            $this->createChildParticipant('[email protected]'), // Child with duplicate - OK
+            $this->createAdultParticipant('[email protected]'), // Duplicate - ERROR
+            $this->createChildParticipant('[email protected]'),      // Unique child - OK
+            $this->createAdultParticipant('[email protected]'),   // Unique - OK
+        ]);
+
+        $violations = $this->validator->validate($bookingDto, null, ['booking_create_step_2']);
+
+        // Should have 2 violations (participants at index 1 and 3)
+        $emailViolations = [];
+        foreach ($violations as $violation) {
+            if (str_contains($violation->getPropertyPath(), '.email')) {
+                $emailViolations[] = $violation;
+            }
+        }
+
+        $this->assertCount(2, $emailViolations);
+
+        // Check that violations are at the correct paths
+        $violationPaths = [];
+        foreach ($emailViolations as $violation) {
+            $violationPaths[] = $violation->getPropertyPath();
+        }
+
+        $this->assertContains('participants[1].email', $violationPaths);
+        $this->assertContains('participants[3].email', $violationPaths);
+    }
+
+    private function createBookingDtoWithParticipants(array $participants): BookingDto
+    {
+        $travel = new Travel();
+        $travel->dateFrom = new \DateTimeImmutable('2025-06-01');
+        $travel->dateTo = new \DateTimeImmutable('2025-06-08');
+
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = $participants;
+
+        return $bookingDto;
+    }
+
+    private function createAdultParticipant(?string $email): ParticipantDto
+    {
+        return $this->createValidParticipant(
+            new \DateTimeImmutable('1990-01-01'), // Adult (over 18)
+            $email
+        );
+    }
+
+    private function createChildParticipant(?string $email): ParticipantDto
+    {
+        return $this->createValidParticipant(
+            new \DateTimeImmutable('2015-01-01'), // Child (under 16)
+            $email
+        );
+    }
+
+    private function createValidParticipant(\DateTimeImmutable $dateOfBirth, ?string $email): ParticipantDto
+    {
+        $participant = new ParticipantDto();
+        $participant->firstName = 'John';
+        $participant->lastName = 'Doe';
+        $participant->dateOfBirth = $dateOfBirth;
+        $participant->email = $email ?? '[email protected]';
+
+        // Set required fields for booking_create_step_2 validation group
+        $participant->assignedRoomId = 1;
+        $participant->skiPass = $this->createMockService();
+        $participant->transportationOutbound = $this->createMockService();
+        $participant->transportationInbound = $this->createMockService();
+
+        return $participant;
+    }
+
+    private function createMockService(): \App\BusProNet\Model\Service
+    {
+        $service = new \App\BusProNet\Model\Service();
+        $service->id = 1;
+        $service->label = 'Test Service';
+        $service->subType = 'TEST';
+        $service->price = 0.0;
+
+        return $service;
+    }
+}

tests/Form/Service/ParticipantEmailFieldHandlerTest.php

@@ -0,0 +1,282 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Form\Service;
+
+use App\BusProNet\Model\Travel;
+use App\Form\Model\BookingDto;
+use App\Form\Model\ParticipantDto;
+use App\Form\Service\ParticipantEmailFieldHandler;
+use PHPUnit\Framework\TestCase;
+
+class ParticipantEmailFieldHandlerTest extends TestCase
+{
+    private ParticipantEmailFieldHandler $handler;
+
+    protected function setUp(): void
+    {
+        $this->handler = new ParticipantEmailFieldHandler();
+    }
+
+    public function testGetFieldName(): void
+    {
+        $this->assertSame('email', $this->handler->getFieldName());
+    }
+
+    public function testGetDependencies(): void
+    {
+        $this->assertSame([], $this->handler->getDependencies());
+    }
+
+    public function testShouldProcessReturnsTrueWhenEmailFieldExists(): void
+    {
+        $this->assertTrue($this->handler->shouldProcess(['email' => '[email protected]'], BookingDto::MODE_CREATE, 0));
+        $this->assertTrue($this->handler->shouldProcess(['email' => null], BookingDto::MODE_EDIT, 5));
+    }
+
+    public function testShouldProcessReturnsFalseWhenEmailFieldMissing(): void
+    {
+        $this->assertFalse($this->handler->shouldProcess([], BookingDto::MODE_CREATE, 0));
+        $this->assertFalse($this->handler->shouldProcess(['firstName' => 'John'], BookingDto::MODE_EDIT, 5));
+    }
+
+    public function testProcessFieldAdultsWithUniqueEmailsNoNotification(): void
+    {
+        $participant1 = $this->createAdultParticipant('[email protected]');
+        $participant2 = $this->createAdultParticipant('[email protected]');
+
+        $travel = new Travel();
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$participant1, $participant2];
+
+        $submittedData = ['email' => '[email protected]'];
+
+        $this->handler->processField($submittedData, $bookingDto, 0);
+
+        $this->assertEmpty($participant1->notifications);
+    }
+
+    public function testProcessFieldAdultsWithDuplicateEmailsAddsWarningNotification(): void
+    {
+        $participant1 = $this->createAdultParticipant('[email protected]');
+        $participant2 = $this->createAdultParticipant('[email protected]');
+
+        $travel = new Travel();
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$participant1, $participant2];
+
+        $submittedData = ['email' => '[email protected]'];
+
+        $this->handler->processField($submittedData, $bookingDto, 0);
+
+        $this->assertCount(1, $participant1->notifications);
+        $this->assertSame('warning', $participant1->notifications[0]['type']);
+        $this->assertSame(
+            'Diese E-Mail Adresse wird bereits von einem anderen erwachsenen Teilnehmer verwendet',
+            $participant1->notifications[0]['message']
+        );
+    }
+
+    public function testProcessFieldAdultWithSameEmailAsChildNoNotification(): void
+    {
+        $adult = $this->createAdultParticipant('[email protected]');
+        $child = $this->createChildParticipant('[email protected]');
+
+        $travel = new Travel();
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$adult, $child];
+
+        $submittedData = ['email' => '[email protected]'];
+
+        $this->handler->processField($submittedData, $bookingDto, 0);
+
+        $this->assertEmpty($adult->notifications);
+    }
+
+    public function testProcessFieldChildWithDuplicateEmailNoNotification(): void
+    {
+        $child1 = $this->createChildParticipant('[email protected]');
+        $child2 = $this->createChildParticipant('[email protected]');
+
+        $travel = new Travel();
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$child1, $child2];
+
+        $submittedData = ['email' => '[email protected]'];
+
+        $this->handler->processField($submittedData, $bookingDto, 0);
+
+        $this->assertEmpty($child1->notifications);
+    }
+
+    public function testProcessFieldChildWithSameEmailAsAdultNoNotification(): void
+    {
+        $adult = $this->createAdultParticipant('[email protected]');
+        $child = $this->createChildParticipant('[email protected]');
+
+        $travel = new Travel();
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$adult, $child];
+
+        $submittedData = ['email' => '[email protected]'];
+
+        // Process child participant (index 1)
+        $this->handler->processField($submittedData, $bookingDto, 1);
+
+        $this->assertEmpty($child->notifications);
+    }
+
+    public function testProcessFieldThreeAdultsWithSameEmailAddsNotification(): void
+    {
+        $participant1 = $this->createAdultParticipant('[email protected]');
+        $participant2 = $this->createAdultParticipant('[email protected]');
+        $participant3 = $this->createAdultParticipant('[email protected]');
+
+        $travel = new Travel();
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$participant1, $participant2, $participant3];
+
+        $submittedData = ['email' => '[email protected]'];
+
+        $this->handler->processField($submittedData, $bookingDto, 0);
+
+        $this->assertCount(1, $participant1->notifications);
+        $this->assertSame('warning', $participant1->notifications[0]['type']);
+    }
+
+    public function testProcessFieldParticipantWithoutBirthDateTreatedAsAdult(): void
+    {
+        $participant1 = new ParticipantDto();
+        $participant1->dateOfBirth = null; // Unknown age - treated as adult
+        $participant1->email = '[email protected]';
+
+        $participant2 = $this->createAdultParticipant('[email protected]');
+
+        $travel = new Travel();
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$participant1, $participant2];
+
+        $submittedData = ['email' => '[email protected]'];
+
+        $this->handler->processField($submittedData, $bookingDto, 0);
+
+        $this->assertCount(1, $participant1->notifications);
+        $this->assertSame('warning', $participant1->notifications[0]['type']);
+    }
+
+    public function testProcessFieldNullEmailSkipsValidation(): void
+    {
+        $participant1 = $this->createAdultParticipant(null);
+        $participant2 = $this->createAdultParticipant(null);
+
+        $travel = new Travel();
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$participant1, $participant2];
+
+        $submittedData = ['email' => null];
+
+        $this->handler->processField($submittedData, $bookingDto, 0);
+
+        $this->assertEmpty($participant1->notifications);
+    }
+
+    public function testProcessFieldEmptyEmailSkipsValidation(): void
+    {
+        $participant1 = $this->createAdultParticipant('');
+        $participant2 = $this->createAdultParticipant('');
+
+        $travel = new Travel();
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$participant1, $participant2];
+
+        $submittedData = ['email' => ''];
+
+        $this->handler->processField($submittedData, $bookingDto, 0);
+
+        $this->assertEmpty($participant1->notifications);
+    }
+
+    public function testProcessFieldWhitespaceOnlyEmailSkipsValidation(): void
+    {
+        $participant1 = $this->createAdultParticipant('   ');
+        $participant2 = $this->createAdultParticipant('   ');
+
+        $travel = new Travel();
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$participant1, $participant2];
+
+        $submittedData = ['email' => '   '];
+
+        $this->handler->processField($submittedData, $bookingDto, 0);
+
+        $this->assertEmpty($participant1->notifications);
+    }
+
+    public function testProcessFieldCaseInsensitiveEmailComparison(): void
+    {
+        $participant1 = $this->createAdultParticipant('[email protected]');
+        $participant2 = $this->createAdultParticipant('[email protected]');
+
+        $travel = new Travel();
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$participant1, $participant2];
+
+        $submittedData = ['email' => '[email protected]'];
+
+        $this->handler->processField($submittedData, $bookingDto, 0);
+
+        $this->assertCount(1, $participant1->notifications);
+        $this->assertSame('warning', $participant1->notifications[0]['type']);
+    }
+
+    public function testProcessFieldWithoutParticipant(): void
+    {
+        $travel = new Travel();
+        $bookingDto = new BookingDto($travel, 1);
+        $submittedData = ['email' => '[email protected]'];
+
+        $this->handler->processField($submittedData, $bookingDto, 0);
+
+        // Should handle gracefully when participant doesn't exist
+        $this->expectNotToPerformAssertions();
+    }
+
+    public function testProcessFieldWithDifferentParticipantIndex(): void
+    {
+        $participant1 = $this->createAdultParticipant('[email protected]');
+        $participant2 = $this->createAdultParticipant('[email protected]');
+        $participant3 = $this->createAdultParticipant('[email protected]');
+
+        $travel = new Travel();
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$participant1, $participant2, $participant3];
+
+        $submittedData = ['email' => '[email protected]'];
+
+        // Process for participant at index 2
+        $this->handler->processField($submittedData, $bookingDto, 2);
+
+        $this->assertEmpty($participant1->notifications); // Should not be affected
+        $this->assertEmpty($participant2->notifications); // Should not be affected
+        $this->assertCount(1, $participant3->notifications); // Should receive warning
+    }
+
+    private function createAdultParticipant(?string $email): ParticipantDto
+    {
+        $participant = new ParticipantDto();
+        $participant->dateOfBirth = new \DateTimeImmutable('1990-01-01'); // Adult (over 18)
+        $participant->email = $email;
+
+        return $participant;
+    }
+
+    private function createChildParticipant(?string $email): ParticipantDto
+    {
+        $participant = new ParticipantDto();
+        $participant->dateOfBirth = new \DateTimeImmutable('2015-01-01'); // Child (under 16)
+        $participant->email = $email;
+
+        return $participant;
+    }
+}