Fixes vehicle register

src/main/java/ch/njol/skript/expressions/ExprVehicle.java

@@ -1,9 +1,10 @@
 package ch.njol.skript.expressions;
 
+import java.util.function.Predicate;
+
 import org.bukkit.entity.Entity;
 import org.bukkit.event.Event;
 import org.bukkit.event.entity.EntityDismountEvent;
-import org.bukkit.event.entity.EntityEvent;
 import org.bukkit.event.entity.EntityMountEvent;
 import org.bukkit.event.vehicle.VehicleEnterEvent;
 import org.bukkit.event.vehicle.VehicleExitEvent;
@@ -15,172 +16,138 @@
 import ch.njol.skript.doc.Examples;
 import ch.njol.skript.doc.Name;
 import ch.njol.skript.doc.Since;
-import ch.njol.skript.effects.Delay;
 import ch.njol.skript.entity.EntityData;
-import ch.njol.skript.expressions.base.SimplePropertyExpression;
-import ch.njol.util.coll.CollectionUtils;
+import ch.njol.skript.expressions.base.PropertyExpression;
+import ch.njol.skript.lang.Expression;
+import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.util.Kleenean;
 
-import java.lang.invoke.MethodHandle;
-import java.lang.invoke.MethodHandles;
-import java.lang.invoke.MethodType;
+import org.bukkit.entity.Player;
 
-/**
- * @author Peter Güttinger
- */
 @Name("Vehicle")
-@Description({"The vehicle an entity is in, if any. This can actually be any entity, e.g. spider jockeys are skeletons that ride on a spider, so the spider is the 'vehicle' of the skeleton.",
-		"See also: <a href='#ExprPassenger'>passenger</a>"})
-@Examples({"vehicle of the player is a minecart"})
+@Description({
+	"The vehicle an entity is in, if any.",
+	"This can actually be any entity, e.g. spider jockeys are skeletons that ride on a spider, so the spider is the 'vehicle' of the skeleton.",
+	"See also: <a href='#ExprPassenger'>passenger</a>"
+})
+@Examples({
+	"set the vehicle of {game::players::*} to a saddled pig",
+	"give {game::players::*} a carrot on a stick",
+	"",
+	"on vehicle enter:",
+		"\tvehicle is a horse",
+		"\tadd 1 to {statistics::horseMounting::%uuid of player%}",
+})
 @Since("2.0")
-public class ExprVehicle extends SimplePropertyExpression<Entity, Entity> {
-
-	private static final boolean HAS_NEW_MOUNT_EVENTS = Skript.classExists("org.bukkit.event.entity.EntityMountEvent");
-
-	private static final boolean HAS_OLD_MOUNT_EVENTS;
-	@Nullable
-	private static final Class<?> OLD_MOUNT_EVENT_CLASS;
-	@Nullable
-	private static final MethodHandle OLD_GETMOUNT_HANDLE;
-	@Nullable
-	private static final Class<?> OLD_DISMOUNT_EVENT_CLASS;
-	@Nullable
-	private static final MethodHandle OLD_GETDISMOUNTED_HANDLE;
+public class ExprVehicle extends PropertyExpression<Entity, Entity> {
 
 	static {
-		register(ExprVehicle.class, Entity.class, "vehicle[s]", "entities");
+		if (Skript.classExists("org.bukkit.event.entity.EntityMountEvent"))
+			registerDefault(ExprVehicle.class, Entity.class, "vehicle[s]", "entities");
+	}
 
-		// legacy support
-		boolean hasOldMountEvents = !HAS_NEW_MOUNT_EVENTS &&
-				Skript.classExists("org.spigotmc.event.entity.EntityMountEvent");
-		Class<?> oldMountEventClass = null;
-		MethodHandle oldGetMountHandle = null;
-		Class<?> oldDismountEventClass = null;
-		MethodHandle oldGetDismountedHandle = null;
-		if (hasOldMountEvents) {
-			try {
-				MethodHandles.Lookup lookup = MethodHandles.lookup();
-				MethodType entityReturnType = MethodType.methodType(Entity.class);
-				// mount event
-				oldMountEventClass = Class.forName("org.spigotmc.event.entity.EntityMountEvent");
-				oldGetMountHandle = lookup.findVirtual(oldMountEventClass, "getMount", entityReturnType);
-				// dismount event
-				oldDismountEventClass = Class.forName("org.spigotmc.event.entity.EntityDismountEvent");
-				oldGetDismountedHandle = lookup.findVirtual(oldDismountEventClass, "getDismounted", entityReturnType);
-			} catch (ClassNotFoundException | IllegalAccessException | NoSuchMethodException e) {
-				hasOldMountEvents = false;
-				oldMountEventClass = null;
-				oldGetMountHandle = null;
-				oldDismountEventClass = null;
-				oldGetDismountedHandle = null;
-				Skript.exception(e, "Failed to load old mount event support.");
-			}
-		}
-		HAS_OLD_MOUNT_EVENTS = hasOldMountEvents;
-		OLD_MOUNT_EVENT_CLASS = oldMountEventClass;
-		OLD_GETMOUNT_HANDLE = oldGetMountHandle;
-		OLD_DISMOUNT_EVENT_CLASS = oldDismountEventClass;
-		OLD_GETDISMOUNTED_HANDLE = oldGetDismountedHandle;
+	@Override
+	@SuppressWarnings("unchecked")
+	public boolean init(Expression<?>[] expressions, int matchedPattern, Kleenean isDelayed, ParseResult parseResult) {
+		setExpr((Expression<Entity>) expressions[0]);
+		return true;
 	}
-	
+
 	@Override
-	protected Entity[] get(final Event e, final Entity[] source) {
+	protected Entity[] get(Event event, Entity[] source) {
 		return get(source, entity -> {
-			if (getTime() >= 0 && e instanceof VehicleEnterEvent && entity.equals(((VehicleEnterEvent) e).getEntered()) && !Delay.isDelayed(e)) {
-				return ((VehicleEnterEvent) e).getVehicle();
+			if (getTime() >= 0 && event instanceof VehicleEnterEvent vehicleEnterEvent && entity.equals(vehicleEnterEvent.getEntered())) {
+				return vehicleEnterEvent.getVehicle();
 			}
-			if (getTime() >= 0 && e instanceof VehicleExitEvent && entity.equals(((VehicleExitEvent) e).getExited()) && !Delay.isDelayed(e)) {
-				return ((VehicleExitEvent) e).getVehicle();
+			if (getTime() <= 0 && event instanceof VehicleExitEvent vehicleExitEvent && entity.equals(vehicleExitEvent.getExited())) {
+				return vehicleExitEvent.getVehicle();
 			}
-			if (
-				(HAS_OLD_MOUNT_EVENTS || HAS_NEW_MOUNT_EVENTS)
-				&& getTime() >= 0 && !Delay.isDelayed(e)
-				&& e instanceof EntityEvent && entity.equals(((EntityEvent) e).getEntity())
-			) {
-				if (HAS_NEW_MOUNT_EVENTS) {
-					if (e instanceof EntityMountEvent)
-						return ((EntityMountEvent) e).getMount();
-					if (e instanceof EntityDismountEvent)
-						return ((EntityDismountEvent) e).getDismounted();
-				} else { // legacy mount event support
-					try {
-						assert OLD_MOUNT_EVENT_CLASS != null;
-						if (OLD_MOUNT_EVENT_CLASS.isInstance(e)) {
-							assert OLD_GETMOUNT_HANDLE != null;
-							return (Entity) OLD_GETMOUNT_HANDLE.invoke(e);
-						}
-						assert OLD_DISMOUNT_EVENT_CLASS != null;
-						if (OLD_DISMOUNT_EVENT_CLASS.isInstance(e)) {
-							assert OLD_GETDISMOUNTED_HANDLE != null;
-							return (Entity) OLD_GETDISMOUNTED_HANDLE.invoke(e);
-						}
-					} catch (Throwable ex) {
-						Skript.exception(ex, "An error occurred while trying to invoke legacy mount event support.");
-					}
-				}
+			if (getTime() >= 0 && event instanceof EntityMountEvent entityMountEvent && entity.equals(entityMountEvent.getEntity())) {
+				return entityMountEvent.getMount();
+			}
+			if (getTime() <= 0 && event instanceof EntityDismountEvent entityDismountEvent && entity.equals(entityDismountEvent.getEntity())) {
+				return entityDismountEvent.getDismounted();
 			}
 			return entity.getVehicle();
 		});
 	}
-
-	@Override
-	@Nullable
-	public Entity convert(final Entity e) {
-		assert false;
-		return e.getVehicle();
-	}
-
-	@Override
-	public Class<? extends Entity> getReturnType() {
-		return Entity.class;
-	}
-
-	@Override
-	protected String getPropertyName() {
-		return "vehicle";
-	}
-
+
 	@Override
-	@Nullable
-	public Class<?>[] acceptChange(final ChangeMode mode) {
+	public Class<?> @Nullable [] acceptChange(ChangeMode mode) {
 		if (mode == ChangeMode.SET) {
+			if (isDefault() && getParser().isCurrentEvent(VehicleExitEvent.class, EntityDismountEvent.class)) {
+				Skript.error("Setting the vehicle during a dismount/exit vehicle event will create an infinite mounting loop.");
+				return null;
+			}
 			return new Class[] {Entity.class, EntityData.class};
 		}
 		return super.acceptChange(mode);
 	}
-	
+
 	@Override
-	public void change(final Event e, final @Nullable Object[] delta, final ChangeMode mode) {
+	public void change(Event event, @Nullable Object[] delta, ChangeMode mode) {
 		if (mode == ChangeMode.SET) {
-			assert delta != null;
-			final Entity[] ps = getExpr().getArray(e);
-			if (ps.length == 0)
+			// The player can desync if setting an entity as it's currently mounting it.
+			// Remember that there can be other entity types aside from players, so only cancel this for players.
+			Predicate<Entity> predicate = Player.class::isInstance;
+			if (event instanceof EntityMountEvent entityMountEvent && predicate.test(entityMountEvent.getEntity())) {
+				return;
+			}
+			if (event instanceof VehicleEnterEvent vehicleEnterEvent && predicate.test(vehicleEnterEvent.getEntered())) {
 				return;
-			final Object o = delta[0];
-			if (o instanceof Entity) {
-				((Entity) o).eject();
-				final Entity p = CollectionUtils.getRandom(ps);
-				assert p != null;
-				p.leaveVehicle();
-				((Entity) o).setPassenger(p);
-			} else if (o instanceof EntityData) {
-				for (final Entity p : ps) {
-					final Entity v = ((EntityData<?>) o).spawn(p.getLocation());
-					if (v == null)
+			}
+			Entity[] passengers = getExpr().getArray(event);
+			if (passengers.length == 0)
+				return;
+			assert delta != null;
+			Object object = delta[0];
+			if (object instanceof Entity entity) {
+				entity.eject();
+				for (Entity passenger : passengers) {
+					// Avoid infinity mounting
+					if (event instanceof VehicleExitEvent && predicate.test(passenger) && passenger.equals(((VehicleExitEvent) event).getExited()))
+						continue;
+					if (event instanceof EntityDismountEvent && predicate.test(passenger) && passenger.equals(((EntityDismountEvent) event).getEntity()))
+						continue;
+					assert passenger != null;
+					passenger.leaveVehicle();
+					entity.addPassenger(passenger);
+				}
+			} else if (object instanceof EntityData entityData) {
+				VehicleExitEvent vehicleExitEvent = event instanceof VehicleExitEvent ? (VehicleExitEvent) event : null;
+				EntityDismountEvent entityDismountEvent = event instanceof EntityDismountEvent ? (EntityDismountEvent) event : null;
+				for (Entity passenger : passengers) {
+					// Avoid infinity mounting
+					if (vehicleExitEvent != null && predicate.test(passenger) && passenger.equals(vehicleExitEvent.getExited()))
+						continue;
+					if (entityDismountEvent != null && predicate.test(passenger) && passenger.equals(entityDismountEvent.getEntity()))
+						continue;
+					Entity vehicle = entityData.spawn(passenger.getLocation());
+					if (vehicle == null)
 						continue;
-					v.setPassenger(p);
+					vehicle.addPassenger(passenger);
 				}
 			} else {
 				assert false;
 			}
 		} else {
-			super.change(e, delta, mode);
+			super.change(event, delta, mode);
 		}
 	}
-
-	@SuppressWarnings("unchecked")
+
 	@Override
-	public boolean setTime(final int time) {
-		return super.setTime(time, getExpr(), VehicleEnterEvent.class, VehicleExitEvent.class);
+	public boolean setTime(int time) {
+		return super.setTime(time, getExpr(), VehicleEnterEvent.class, VehicleExitEvent.class, EntityMountEvent.class, EntityDismountEvent.class);
 	}
-
+
+	@Override
+	public Class<? extends Entity> getReturnType() {
+		return Entity.class;
+	}
+
+	@Override
+	public String toString(@Nullable Event event, boolean debug) {
+		return "vehicle of " + getExpr().toString(event, debug);
+	}
+
 }