working

tools/java/LandtrainConstraintAuthHelper.java

@@ -0,0 +1,38 @@
+package zombie.vehicles;
+
+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.
+ */
+public final class LandtrainConstraintAuthHelper {
+    private LandtrainConstraintAuthHelper() {
+    }
+
+    public static IsoGameCharacter resolveConstraintDriver(BaseVehicle vehicle) {
+        if (vehicle == null) {
+            return null;
+        }
+
+        IsoGameCharacter driver = vehicle.getDriver();
+        if (driver != null) {
+            return driver;
+        }
+
+        BaseVehicle front = vehicle.getVehicleTowedBy();
+        if (front != null) {
+            driver = front.getDriver();
+            if (driver != null) {
+                return driver;
+            }
+        }
+
+        BaseVehicle rear = vehicle.getVehicleTowing();
+        if (rear != null) {
+            return rear.getDriver();
+        }
+
+        return null;
+    }
+}