ProtocolLib/src/main/java/com/comphenix/protocol/wrappers/WrappedEnumEntityUseAction.java

package com.comphenix.protocol.wrappers;

import java.lang.reflect.Modifier;
import java.util.Arrays;

import com.comphenix.protocol.PacketType;
import com.comphenix.protocol.reflect.EquivalentConverter;
import com.comphenix.protocol.reflect.FuzzyReflection;
import com.comphenix.protocol.reflect.accessors.Accessors;
import com.comphenix.protocol.reflect.accessors.ConstructorAccessor;
import com.comphenix.protocol.reflect.accessors.FieldAccessor;
import com.comphenix.protocol.reflect.accessors.MethodAccessor;
import com.comphenix.protocol.reflect.fuzzy.FuzzyFieldContract;
import com.comphenix.protocol.utility.MinecraftReflection;
import com.comphenix.protocol.wrappers.EnumWrappers.EntityUseAction;
import com.comphenix.protocol.wrappers.EnumWrappers.Hand;

import org.bukkit.util.Vector;

/**
 * Represents an entity used action used in the UseEntity packet sent by the client.
 * @author derklaro
 */
public class WrappedEnumEntityUseAction extends AbstractWrapper implements ClonableWrapper {

	public static final EquivalentConverter<WrappedEnumEntityUseAction> CONVERTER = Converters.handle(AbstractWrapper::getHandle,
			WrappedEnumEntityUseAction::fromHandle, WrappedEnumEntityUseAction.class);

	private static final Class<?> PACKET_CLASS = PacketType.Play.Client.USE_ENTITY.getPacketClass();
	private static final Class<?>[] DECLARED_CLASSES = PACKET_CLASS.getDeclaredClasses();

	private static final Class<?> HANDLE_TYPE = MinecraftReflection.getEnumEntityUseActionClass();
	private static final MethodAccessor ACTION_USE = MinecraftReflection.getEntityUseActionEnumMethodAccessor();

	private static final ConstructorAccessor INTERACT = useAction(EnumWrappers.getHandClass());
	private static final ConstructorAccessor INTERACT_AT = useAction(EnumWrappers.getHandClass(),
			MinecraftReflection.getVec3DClass());

	private static final Object ATTACK = Accessors.getFieldAccessor(FuzzyReflection.fromClass(PACKET_CLASS, true)
			.getField(FuzzyFieldContract.newBuilder()
					.requireModifier(Modifier.STATIC)
					.typeExact(MinecraftReflection.getEnumEntityUseActionClass())
					.build())
	).get(null);
	private static final WrappedEnumEntityUseAction ATTACK_WRAPPER = new WrappedEnumEntityUseAction(ATTACK);

	private final EntityUseAction action;
	// these fields are only available for interact & interact_at
	private FieldAccessor handAccessor;
	private FieldAccessor positionAccessor;

	/**
	 * Construct a new wrapper for the entity use action class in the UseEntity packet.
	 * @param handle - the NMS handle.
	 */
	private WrappedEnumEntityUseAction(Object handle) {
		super(HANDLE_TYPE);
		setHandle(handle);

		action = EnumWrappers.getEntityUseActionConverter().getSpecific(ACTION_USE.invoke(handle));
	}

	/**
	 * Finds a constructor of a declared class in the UseEntity class. Used to find the action class implementations.
	 * @param parameterTypes - the types the constructor of the class must have.
	 * @return a constructor for a matching class.
	 * @throws IllegalArgumentException if no constructor was found.
	 */
	private static ConstructorAccessor useAction(Class<?>... parameterTypes) {
		for (Class<?> subClass : DECLARED_CLASSES) {
			ConstructorAccessor accessor = Accessors.getConstructorAccessorOrNull(subClass, parameterTypes);
			if (accessor != null) {
				return accessor;
			}
		}
		throw new IllegalArgumentException(
				"No constructor with " + Arrays.toString(parameterTypes) + " in " + PACKET_CLASS);
	}

	/**
	 * Construct a new wrapper for the entity use action class in the UseEntity packet.
	 * @param handle - the NMS handle.
	 * @return the created wrapper.
	 */
	public static WrappedEnumEntityUseAction fromHandle(Object handle) {
		return new WrappedEnumEntityUseAction(handle);
	}

	/**
	 * Get the jvm static action for attacking an entity.
	 * @return the action for an entity attack.
	 */
	public static WrappedEnumEntityUseAction attack() {
		return ATTACK_WRAPPER;
	}

	/**
	 * Get an action for interacting with an entity.
	 * @param hand - the hand used for the interact.
	 * @return the action for an interact.
	 */
	public static WrappedEnumEntityUseAction interact(Hand hand) {
		Object handle = INTERACT.invoke(EnumWrappers.getHandConverter().getGeneric(hand));
		return new WrappedEnumEntityUseAction(handle);
	}

	/**
	 * Get an action for interacting with an entity at a specific location.
	 * @param hand - the hand used for the interact.
	 * @param vector - the position of the interact.
	 * @return the action for an interact_at.
	 */
	public static WrappedEnumEntityUseAction interactAt(Hand hand, Vector vector) {
		Object handle = INTERACT_AT.invoke(EnumWrappers.getHandConverter().getGeneric(hand),
				BukkitConverters.getVectorConverter().getGeneric(vector));
		return new WrappedEnumEntityUseAction(handle);
	}

	/**
	 * Get the action used for the interact.
	 * @return the interact action.
	 */
	public EntityUseAction getAction() {
		return action;
	}

	/**
	 * Get the hand used for the interact. Only available if this represents interact or interact_at.
	 * @return the hand used for the interact.
	 * @throws IllegalArgumentException if called for attack.
	 */
	public Hand getHand() {
		return EnumWrappers.getHandConverter().getSpecific(getHandAccessor().get(handle));
	}

	/**
	 * Sets the hand used for the interact.
	 * @param hand the used hand.
	 * @throws IllegalArgumentException if called for attack.
	 */
	public void setHand(Hand hand) {
		getHandAccessor().set(handle, EnumWrappers.getHandConverter().getGeneric(hand));
	}

	/**
	 * Get the position of the interact. Only available if this represents interact_at.
	 * @return the position of the interact.
	 * @throws IllegalArgumentException if called for attack or interact.
	 */
	public Vector getPosition() {
		return BukkitConverters.getVectorConverter().getSpecific(getPositionAccessor().get(handle));
	}

	/**
	 * Sets the position of the interact.
	 * @param position the position.
	 * @throws IllegalArgumentException if called for attack or interact.
	 */
	public void setPosition(Vector position) {
		getPositionAccessor().set(handle, BukkitConverters.getVectorConverter().getGeneric(position));
	}

	@Override
	public WrappedEnumEntityUseAction deepClone() {
		switch (action) {
			case ATTACK:
				return WrappedEnumEntityUseAction.attack();
			case INTERACT:
				return WrappedEnumEntityUseAction.interact(getHand());
			case INTERACT_AT:
				return WrappedEnumEntityUseAction.interactAt(getHand(), getPosition());
			default:
				throw new IllegalArgumentException("Invalid EntityUseAction: " + action);
		}
	}

	/**
	 * Get a field accessor for the hand in the interact and interact_at type.
	 * @return a field accessor for the hand field.
	 * @throws IllegalArgumentException if called for attack.
	 */
	private FieldAccessor getHandAccessor() {
		if (handAccessor == null) {
			handAccessor = MinecraftReflection.getHandEntityUseActionEnumFieldAccessor(handle);
		}
		return handAccessor;
	}

	/**
	 * Get a field accessor for the position in the interact_at type.
	 * @return a field accessor for the position field.
	 * @throws IllegalArgumentException if called for attack or interact.
	 */
	public FieldAccessor getPositionAccessor() {
		if (positionAccessor == null) {
			positionAccessor = MinecraftReflection.getVec3EntityUseActionEnumFieldAccessor(handle);
		}
		return positionAccessor;
	}
}