feat: selectable drop-offs for inbound bus travel

src/Validator/Constraints/ParticipantValidator.php

@@ -22,6 +22,7 @@ class ParticipantValidator extends ConstraintValidator
         $participant = $value;
 
         $this->assertPickupSelected($participant);
+        $this->assertDropOffSelected($participant);
         $this->assertBodyDimensionsWhenRentalsSelected($participant);
     }
 
@@ -42,6 +43,29 @@ class ParticipantValidator extends ConstraintValidator
         }
     }
 
+    public function assertDropOffSelected(ParticipantDto $participant): void
+    {
+        $hasOutboundBus = null !== $participant->transportationOutbound
+            && 'BUS' === $participant->transportationOutbound->subType;
+        $hasInboundBus = null !== $participant->transportationInbound
+            && 'BUS' === $participant->transportationInbound->subType;
+
+        if (false === $hasInboundBus) {
+            return;
+        }
+
+        // BUS+BUS: drop-off required only when differentDropOff checkbox is checked
+        // PKW+BUS: drop-off always required (no checkbox, field shown directly)
+        $requireDropOff = $hasOutboundBus ? $participant->differentDropOff : true;
+
+        if ($requireDropOff && null === $participant->dropOff) {
+            $this->context->buildViolation('Bitte auswählen')
+                ->atPath('dropOff')
+                ->addViolation()
+            ;
+        }
+    }
+
     public function assertBodyDimensionsWhenRentalsSelected(ParticipantDto $participant): void
     {
         // Check if any rental services are selected