Improve resiliency of the correlation listener

Signed-off-by: TTtie <[email protected]>

util/src/main/java/tc/oc/pgm/util/listener/TNTMinecartPlacementListener.java

@@ -1,8 +1,11 @@
 package tc.oc.pgm.util.listener;
 
 import org.bukkit.Bukkit;
+import org.bukkit.Location;
 import org.bukkit.Material;
 import org.bukkit.entity.Player;
+import org.bukkit.entity.Vehicle;
+import org.bukkit.entity.minecart.ExplosiveMinecart;
 import org.bukkit.event.*;
 import org.bukkit.event.player.PlayerInteractEvent;
 import org.bukkit.event.vehicle.VehicleCreateEvent;
@@ -22,6 +25,7 @@
 public class TNTMinecartPlacementListener implements Listener {
   private Player lastPlacer;
   private ItemStack placingStack;
+  private Location railLocation;
 
   private static void handleCall(Event pgmEvent, Event bukkitEvent) {
     if (bukkitEvent instanceof Cancellable) {
@@ -39,34 +43,51 @@ public void onInteraction(PlayerInteractEvent event) {
     if (stack != null && stack.getType() == Material.EXPLOSIVE_MINECART) {
       lastPlacer = event.getPlayer();
       placingStack = stack.clone();
+      railLocation = event.getClickedBlock().getLocation();
     }
   }
 
-  @EventHandler(ignoreCancelled = true)
+  @EventHandler
   public void onVehicleCreate(VehicleCreateEvent event) {
-    if (lastPlacer != null) {
-      PlayerSpawnEntityEvent pgmEvent =
-          new PlayerSpawnEntityEvent(
-              lastPlacer,
-              event.getVehicle(),
-              event.getVehicle().getLocation(),
-              lastPlacer.getItemInHand());
-      handleCall(pgmEvent, event);
+    /*
+     * Starting from 1.11.2, VehicleCreateEvent is natively cancellable.
+     * Even then, we should account for this case and reset the variables
+     * to ensure the tracking works reliably.
+     */
+    if (!(event instanceof Cancellable) || !((Cancellable) event).isCancelled()) {
+      if (lastPlacer != null) {
+        Vehicle vehicle = event.getVehicle();
+        Location vehicleLocation = vehicle.getLocation();
 
-      /*
-       * This block only exists to ensure consistency, as VehicleCreateEvent
-       * is natively cancellable starting from 1.11.2. The TNT minecart is
-       * still being used up, however.
-       */
-      if (pgmEvent.isCancelled()) {
-        if (!(event instanceof Cancellable)) {
-          event.getVehicle().remove();
+        if (vehicle instanceof ExplosiveMinecart
+            && areBlockLocationsEqual(railLocation, vehicleLocation)) {
+          ItemStack itemInHand = lastPlacer.getItemInHand();
+
+          PlayerSpawnEntityEvent pgmEvent =
+              new PlayerSpawnEntityEvent(
+                  lastPlacer,
+                  vehicle,
+                  vehicleLocation,
+                  itemInHand != null ? itemInHand : placingStack);
+          handleCall(pgmEvent, event);
+
+          if (pgmEvent.isCancelled()) {
+            if (!(event instanceof Cancellable)) {
+              vehicle.remove();
+            }
+            lastPlacer.getInventory().setItemInHand(placingStack);
+          }
         }
-        lastPlacer.getInventory().setItemInHand(placingStack);
       }
     }
-
     lastPlacer = null;
     placingStack = null;
+    railLocation = null;
+  }
+
+  private static boolean areBlockLocationsEqual(Location locA, Location locB) {
+    return locA.getBlockX() == locB.getBlockX()
+        && locA.getBlockY() == locB.getBlockY()
+        && locA.getBlockZ() == locB.getBlockZ();
   }
 }