Add Leash Event and Its Methods (#6427)

* Add leash event and its methods

* Fix a woopsy in EvtLeash.java

* Attempt to fix branch

* Make ExprUnleashReason extend EVE

* Bulk requested changes

* Requested changes

* Remove license header (#6684)

* Requested changes

* Merge branch 'dev/feature' into feature/event-leash

* Pickle changes

* Replace Getter, optimize imports

* Remove duplicate value registration.

Co-authored-by: Moderocky <admin@moderocky.com>

---------

Co-authored-by: Moderocky <admin@moderocky.com>

src/main/java/ch/njol/skript/classes/data/BukkitClasses.java

@@ -58,6 +58,7 @@
 import org.bukkit.event.entity.EntityPotionEffectEvent;
 import org.bukkit.event.entity.EntityRegainHealthEvent.RegainReason;
 import org.bukkit.event.entity.EntityTransformEvent.TransformReason;
+import org.bukkit.event.entity.EntityUnleashEvent;
 import org.bukkit.event.inventory.ClickType;
 import org.bukkit.event.inventory.InventoryAction;
 import org.bukkit.event.inventory.InventoryCloseEvent;
@@ -1508,6 +1509,12 @@ public String toVariableNameString(EnchantmentOffer eo) {
 				.description("Represents a transform reason of an <a href='events.html#entity transform'>entity transform event</a>.")
 				.since("2.8.0"));
 
+		Classes.registerClass(new EnumClassInfo<>(EntityUnleashEvent.UnleashReason.class, "unleashreason", "unleash reasons")
+			.user("unleash ?(reason|cause)s?")
+			.name("Unleash Reason")
+			.description("Represents an unleash reason of an unleash event.")
+			.since("INSERT VERSION"));
+
 		Classes.registerClass(new EnumClassInfo<>(ItemFlag.class, "itemflag", "item flags")
 				.user("item ?flags?")
 				.name("Item Flag")

src/main/java/ch/njol/skript/conditions/CondLeashWillDrop.java

@@ -0,0 +1,56 @@
+package ch.njol.skript.conditions;
+
+import org.bukkit.event.Event;
+import org.bukkit.event.entity.EntityUnleashEvent;
+import org.jetbrains.annotations.Nullable;
+
+import ch.njol.skript.Skript;
+import ch.njol.skript.doc.*;
+import ch.njol.skript.lang.Condition;
+import ch.njol.skript.lang.Expression;
+import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.util.Kleenean;
+
+@Name("Leash Will Drop")
+@Description("Checks whether the leash item will drop during the leash detaching in an unleash event.")
+@Examples({
+	"on unleash:",
+		"\tif the leash will drop:",
+			"\t\tprevent the leash from dropping",
+		"\telse:",
+			"\t\tallow the leash to drop"
+})
+@Keywords("lead")
+@Events("Unleash")
+@RequiredPlugins("Paper 1.16+")
+@Since("INSERT VERSION")
+public class CondLeashWillDrop extends Condition {
+
+	static {
+		if (Skript.methodExists(EntityUnleashEvent.class, "isDropLeash"))
+			Skript.registerCondition(CondLeashWillDrop.class, "[the] (lead|leash) [item] (will|not:(won't|will not)) (drop|be dropped)");
+	}
+
+	@Override
+	public boolean init(Expression<?>[] expressions, int matchedPattern, Kleenean isDelayed, ParseResult parseResult) {
+		if (!getParser().isCurrentEvent(EntityUnleashEvent.class)) {
+			Skript.error("The 'leash will drop' condition can only be used in an 'unleash' event");
+			return false;
+		}
+		setNegated(parseResult.hasTag("not"));
+		return true;
+	}
+
+	@Override
+	public boolean check(Event event) {
+		if (!(event instanceof EntityUnleashEvent unleashEvent))
+			return false;
+		return unleashEvent.isDropLeash() ^ isNegated();
+	}
+
+	@Override
+	public String toString(@Nullable Event event, boolean debug) {
+		return "the leash will" + (isNegated() ? " not" : "") + " be dropped";
+	}
+
+}

src/main/java/ch/njol/skript/effects/EffDropLeash.java

@@ -0,0 +1,59 @@
+package ch.njol.skript.effects;
+
+import org.bukkit.event.Event;
+import org.bukkit.event.entity.EntityUnleashEvent;
+import org.jetbrains.annotations.Nullable;
+
+import ch.njol.skript.Skript;
+import ch.njol.skript.doc.*;
+import ch.njol.skript.lang.Effect;
+import ch.njol.skript.lang.Expression;
+import ch.njol.skript.lang.SkriptParser;
+import ch.njol.util.Kleenean;
+
+@Name("Allow / Prevent Leash Drop")
+@Description("Allows or prevents the leash from being dropped in an unleash event.")
+@Examples({
+	"on unleash:",
+		"\tif player is not set:",
+			"\t\tprevent the leash from dropping",
+		"\telse if player is op:",
+			"\t\tallow the leash to drop"
+})
+@Keywords("lead")
+@Events("Unleash")
+@Since("INSERT VERSION")
+public class EffDropLeash extends Effect {
+
+	static {
+			Skript.registerEffect(EffDropLeash.class,
+					"(force|allow) [the] (lead|leash) [item] to drop",
+					"(block|disallow|prevent) [the] (lead|leash) [item] from dropping"
+		);
+	}
+
+	private boolean allowLeashDrop;
+
+	@Override
+	public boolean init(Expression<?>[] expressions, int matchedPattern, Kleenean isDelayed, SkriptParser.ParseResult parseResult) {
+		if (!getParser().isCurrentEvent(EntityUnleashEvent.class)) {
+			Skript.error("The 'drop leash' effect can only be used in an 'unleash' event");
+			return false;
+		}
+		allowLeashDrop = matchedPattern == 0;
+		return true;
+	}
+
+	@Override
+	protected void execute(Event event) {
+		if (!(event instanceof EntityUnleashEvent unleashEvent))
+			return;
+		unleashEvent.setDropLeash(allowLeashDrop);
+	}
+
+	@Override
+	public String toString(@Nullable Event event, boolean debug) {
+		return allowLeashDrop ? "allow the leash to drop" : "prevent the leash from dropping";
+	}
+
+}

src/main/java/ch/njol/skript/events/EvtLeash.java

@@ -0,0 +1,126 @@
+package ch.njol.skript.events;
+
+import org.bukkit.entity.Entity;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Event;
+import org.bukkit.event.entity.EntityUnleashEvent;
+import org.bukkit.event.entity.PlayerLeashEntityEvent;
+import org.bukkit.event.player.PlayerUnleashEntityEvent;
+import org.jetbrains.annotations.Nullable;
+
+import ch.njol.skript.Skript;
+import ch.njol.skript.entity.EntityData;
+import ch.njol.skript.lang.Literal;
+import ch.njol.skript.lang.SkriptEvent;
+import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.skript.registrations.Classes;
+import ch.njol.skript.registrations.EventValues;
+import ch.njol.util.coll.CollectionUtils;
+
+public class EvtLeash extends SkriptEvent {
+
+	static {
+		Skript.registerEvent("Leash / Unleash", EvtLeash.class, CollectionUtils.array(PlayerLeashEntityEvent.class, EntityUnleashEvent.class), "[:player] [:un]leash[ing] [of %-entitydatas%]")
+			.description("Called when an entity is leashed or unleashed. Cancelling these events will prevent the leashing or unleashing from occurring.")
+			.examples(
+					"on player leash of a sheep:",
+						"\tsend \"Baaaaa--\" to player",
+					"",
+					"on player leash:",
+						"\tsend \"<%event-entity%> Let me go!\" to player",
+					"",
+					"on unleash:",
+						"\tbroadcast \"<%event-entity%> I'm free\"",
+					"",
+					"on player unleash:",
+						"\tsend \"<%event-entity%> Thanks for freeing me!\" to player"
+			)
+			.since("INSERT VERSION");
+
+		// PlayerLeashEntityEvent
+		// event-player is explicitly registered due to event does not extend PlayerEvent
+		EventValues.registerEventValue(PlayerLeashEntityEvent.class, Player.class, PlayerLeashEntityEvent::getPlayer);
+		EventValues.registerEventValue(PlayerLeashEntityEvent.class, Entity.class, PlayerLeashEntityEvent::getEntity);
+
+		// EntityUnleashEvent
+		EventValues.registerEventValue(EntityUnleashEvent.class, EntityUnleashEvent.UnleashReason.class, EntityUnleashEvent::getReason);
+
+		// PlayerUnleashEntityEvent
+		EventValues.registerEventValue(PlayerUnleashEntityEvent.class, Player.class, PlayerUnleashEntityEvent::getPlayer);
+	}
+
+	private enum EventType {
+
+		LEASH("leash"),
+		UNLEASH("unleash"),
+		UNLEASH_BY_PLAYER("player unleash");
+
+		private final String name;
+
+		EventType(String name) {
+			this.name = name;
+		}
+
+
+		@Override
+		public String toString() {
+			return name;
+		}
+
+	}
+
+	private @Nullable EntityData<?>[] types;
+	private EventType eventType;
+
+	@Override
+	public boolean init(Literal<?>[] args, int matchedPattern, ParseResult parseResult) {
+		//noinspection unchecked
+		types = args[0] == null ? null : ((Literal<EntityData<?>>) args[0]).getAll();
+		eventType = EventType.LEASH;
+		if (parseResult.hasTag("un")) {
+			eventType = EventType.UNLEASH;
+			if (parseResult.hasTag("player")) {
+				eventType = EventType.UNLEASH_BY_PLAYER;
+			}
+		}
+		return true;
+	}
+
+	@Override
+	public boolean check(Event event) {
+		Entity leashedEntity;
+		switch (eventType) {
+            case LEASH -> {
+				if (!(event instanceof PlayerLeashEntityEvent playerLeash))
+					return false;
+				leashedEntity = playerLeash.getEntity();
+			}
+            case UNLEASH -> {
+				if (!(event instanceof EntityUnleashEvent entityUnleash))
+					return false;
+				leashedEntity = entityUnleash.getEntity();
+			}
+            case UNLEASH_BY_PLAYER -> {
+				if (!(event instanceof PlayerUnleashEntityEvent playerUnleash))
+					return false;
+				leashedEntity = playerUnleash.getEntity();
+			}
+            default -> {
+                return false;
+            }
+        }
+		if (types == null)
+			return true;
+		for (EntityData<?> entityData : types) {
+			if (entityData.isInstance(leashedEntity))
+				return true;
+		}
+		return false;
+	}
+
+	@Override
+	public String toString(@Nullable Event event, boolean debug) {
+		return eventType + (types != null ? " of " + Classes.toString(types, false) : "");
+	}
+
+}

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

@@ -0,0 +1,65 @@
+package ch.njol.skript.expressions;
+
+import org.bukkit.event.Event;
+import org.bukkit.event.entity.EntityUnleashEvent;
+import org.bukkit.event.entity.EntityUnleashEvent.UnleashReason;
+import org.jetbrains.annotations.Nullable;
+
+import ch.njol.skript.Skript;
+import ch.njol.skript.doc.*;
+import ch.njol.skript.expressions.base.EventValueExpression;
+import ch.njol.skript.lang.Expression;
+import ch.njol.skript.lang.ExpressionType;
+import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.util.Kleenean;
+
+@Name("Unleash Reason")
+@Description("The unleash reason in an unleash event.")
+@Examples({
+	"if the unleash reason is distance:",
+		"\tbroadcast \"The leash was snapped in half.\""
+})
+@Events("Unleash")
+@Since("INSERT VERSION")
+public class ExprUnleashReason extends EventValueExpression<UnleashReason> {
+
+	public ExprUnleashReason() {
+		super(UnleashReason.class);
+	}
+
+	static {
+		Skript.registerExpression(ExprUnleashReason.class, EntityUnleashEvent.UnleashReason.class, ExpressionType.SIMPLE, "[the] unleash[ing] reason");
+	}
+
+	@Override
+	public boolean init(Expression<?>[] expressions, int matchedPattern, Kleenean isDelayed, ParseResult parseResult) {
+		if (!getParser().isCurrentEvent(EntityUnleashEvent.class)) {
+			Skript.error("The 'unleash reason' expression can only be used in an 'unleash' event");
+			return false;
+		}
+		return true;
+	}
+
+	@Override
+	protected UnleashReason[] get(Event event) {
+		if (!(event instanceof EntityUnleashEvent unleashEvent))
+			return new UnleashReason[0];
+		return new UnleashReason[] {unleashEvent.getReason()};
+	}
+
+	@Override
+	public boolean isSingle() {
+		return true;
+	}
+
+	@Override
+	public Class<? extends UnleashReason> getReturnType() {
+		return UnleashReason.class;
+	}
+
+	@Override
+	public String toString(@Nullable Event event, boolean debug) {
+		return "the unleash reason";
+	}
+
+}

src/main/resources/lang/default.lang

@@ -2401,6 +2401,13 @@ transform reasons:
 	unknown: unknown
 	infection: infection, villager infection
 
+# -- Unleash Reasons --
+unleash reasons:
+	distance: distance
+	holder_gone: holder (gone|disappeared)
+	player_unleash: player unleash, player unleashed, unleashed by player
+	unknown: unknown
+
 # -- Item Flags --
 item flags:
     hide_additional_tooltip: hide additional tooltip, additional tooltip hidden, hidden additional tooltip
@@ -2617,6 +2624,7 @@ types:
 	quitreason: quit reason¦s @a
 	inventoryclosereason: inventory close reason¦s @an
 	transformreason: transform reason¦s @a
+	unleashreason: unleash reason¦s @an
 	display: display¦s @a
 	billboard: billboard¦s @a
 	textalignment: text alignment¦s @a