Schmedium

tools/java/LandtrainConstraintAuthHelper.java

@@ -1,10 +1,12 @@
 package zombie.vehicles;
 
+import java.util.HashSet;
+import java.util.Set;
 import zombie.characters.IsoGameCharacter;
 
 /**
  * Resolves the effective driver for constraint auth in chained towing.
- * For middle vehicles in a chain, prefer the front/lead driver's authority.
+ * For middle vehicles in a chain, scan through links so long trains still resolve authority.
  */
 public final class LandtrainConstraintAuthHelper {
     private LandtrainConstraintAuthHelper() {
@@ -15,24 +17,49 @@ public final class LandtrainConstraintAuthHelper {
             return null;
         }
 
-        IsoGameCharacter driver = vehicle.getDriver();
-        if (driver != null) {
-            return driver;
-        }
+        IsoGameCharacter driver = findDriverAlongChain(vehicle, true);
+        if (driver != null) return driver;
+        return findDriverAlongChain(vehicle, false);
+    }
 
-        BaseVehicle front = vehicle.getVehicleTowedBy();
-        if (front != null) {
-            driver = front.getDriver();
+    private static IsoGameCharacter findDriverAlongChain(BaseVehicle start, boolean towardFront) {
+        BaseVehicle cursor = start;
+        Set<Integer> visited = new HashSet<>();
+
+        while (cursor != null) {
+            int id = cursor.getId();
+            if (!visited.add(id)) {
+                // Safety: malformed link graph; stop scanning.
+                return null;
+            }
+
+            IsoGameCharacter driver = cursor.getDriver();
             if (driver != null) {
                 return driver;
             }
-        }
 
-        BaseVehicle rear = vehicle.getVehicleTowing();
-        if (rear != null) {
-            return rear.getDriver();
+            cursor = towardFront ? cursor.getVehicleTowedBy() : cursor.getVehicleTowing();
         }
 
         return null;
     }
+
+    public static boolean isEnterBlockedLandtrain(
+            BaseVehicle vehicle, IsoGameCharacter chr, int seat) {
+        if (isVehicleBeingTowedInLandtrain(vehicle)) {
+            return true;
+        }
+        return vehicle != null && vehicle.isExitBlocked(chr, seat);
+    }
+
+    public static boolean isEnterBlocked2Landtrain(BaseVehicle vehicle, int seat) {
+        if (isVehicleBeingTowedInLandtrain(vehicle)) {
+            return true;
+        }
+        return vehicle != null && vehicle.isExitBlocked2(seat);
+    }
+
+    private static boolean isVehicleBeingTowedInLandtrain(BaseVehicle vehicle) {
+        return vehicle != null && vehicle.getVehicleTowedBy() != null;
+    }
 }