minecraft-src/net/minecraft/network/protocol/game/ServerboundInteractPacket.java

package net.minecraft.network.protocol.game;

import java.util.function.Function;
import net.minecraft.network.FriendlyByteBuf;
import net.minecraft.network.codec.StreamCodec;
import net.minecraft.network.protocol.Packet;
import net.minecraft.network.protocol.PacketType;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.world.InteractionHand;
import net.minecraft.world.entity.Entity;
import net.minecraft.world.phys.Vec3;
import org.jetbrains.annotations.Nullable;

public class ServerboundInteractPacket implements Packet<ServerGamePacketListener> {
	public static final StreamCodec<FriendlyByteBuf, ServerboundInteractPacket> STREAM_CODEC = Packet.codec(
		ServerboundInteractPacket::write, ServerboundInteractPacket::new
	);
	private final int entityId;
	private final ServerboundInteractPacket.Action action;
	private final boolean usingSecondaryAction;
	static final ServerboundInteractPacket.Action ATTACK_ACTION = new ServerboundInteractPacket.Action() {
		@Override
		public ServerboundInteractPacket.ActionType getType() {
			return ServerboundInteractPacket.ActionType.ATTACK;
		}

		@Override
		public void dispatch(ServerboundInteractPacket.Handler handler) {
			handler.onAttack();
		}

		@Override
		public void write(FriendlyByteBuf buffer) {
		}
	};

	private ServerboundInteractPacket(int entityId, boolean usingSecondaryAction, ServerboundInteractPacket.Action action) {
		this.entityId = entityId;
		this.action = action;
		this.usingSecondaryAction = usingSecondaryAction;
	}

	public static ServerboundInteractPacket createAttackPacket(Entity entity, boolean usingSecondaryAction) {
		return new ServerboundInteractPacket(entity.getId(), usingSecondaryAction, ATTACK_ACTION);
	}

	public static ServerboundInteractPacket createInteractionPacket(Entity entity, boolean usingSecondaryAction, InteractionHand hand) {
		return new ServerboundInteractPacket(entity.getId(), usingSecondaryAction, new ServerboundInteractPacket.InteractionAction(hand));
	}

	public static ServerboundInteractPacket createInteractionPacket(Entity entity, boolean usingSecondaryAction, InteractionHand hand, Vec3 interactionLocation) {
		return new ServerboundInteractPacket(
			entity.getId(), usingSecondaryAction, new ServerboundInteractPacket.InteractionAtLocationAction(hand, interactionLocation)
		);
	}

	private ServerboundInteractPacket(FriendlyByteBuf buffer) {
		this.entityId = buffer.readVarInt();
		ServerboundInteractPacket.ActionType actionType = buffer.readEnum(ServerboundInteractPacket.ActionType.class);
		this.action = (ServerboundInteractPacket.Action)actionType.reader.apply(buffer);
		this.usingSecondaryAction = buffer.readBoolean();
	}

	/**
	 * Writes the raw packet data to the data stream.
	 */
	private void write(FriendlyByteBuf buffer) {
		buffer.writeVarInt(this.entityId);
		buffer.writeEnum(this.action.getType());
		this.action.write(buffer);
		buffer.writeBoolean(this.usingSecondaryAction);
	}

	@Override
	public PacketType<ServerboundInteractPacket> type() {
		return GamePacketTypes.SERVERBOUND_INTERACT;
	}

	/**
	 * Passes this Packet on to the NetHandler for processing.
	 */
	public void handle(ServerGamePacketListener handler) {
		handler.handleInteract(this);
	}

	@Nullable
	public Entity getTarget(ServerLevel level) {
		return level.getEntityOrPart(this.entityId);
	}

	public boolean isUsingSecondaryAction() {
		return this.usingSecondaryAction;
	}

	public void dispatch(ServerboundInteractPacket.Handler handler) {
		this.action.dispatch(handler);
	}

	interface Action {
		ServerboundInteractPacket.ActionType getType();

		void dispatch(ServerboundInteractPacket.Handler handler);

		void write(FriendlyByteBuf buffer);
	}

	static enum ActionType {
		INTERACT(ServerboundInteractPacket.InteractionAction::new),
		ATTACK(friendlyByteBuf -> ServerboundInteractPacket.ATTACK_ACTION),
		INTERACT_AT(ServerboundInteractPacket.InteractionAtLocationAction::new);

		final Function<FriendlyByteBuf, ServerboundInteractPacket.Action> reader;

		private ActionType(final Function<FriendlyByteBuf, ServerboundInteractPacket.Action> reader) {
			this.reader = reader;
		}
	}

	public interface Handler {
		void onInteraction(InteractionHand hand);

		void onInteraction(InteractionHand hand, Vec3 interactionLocation);

		void onAttack();
	}

	static class InteractionAction implements ServerboundInteractPacket.Action {
		private final InteractionHand hand;

		InteractionAction(InteractionHand hand) {
			this.hand = hand;
		}

		private InteractionAction(FriendlyByteBuf buffer) {
			this.hand = buffer.readEnum(InteractionHand.class);
		}

		@Override
		public ServerboundInteractPacket.ActionType getType() {
			return ServerboundInteractPacket.ActionType.INTERACT;
		}

		@Override
		public void dispatch(ServerboundInteractPacket.Handler handler) {
			handler.onInteraction(this.hand);
		}

		@Override
		public void write(FriendlyByteBuf buffer) {
			buffer.writeEnum(this.hand);
		}
	}

	static class InteractionAtLocationAction implements ServerboundInteractPacket.Action {
		private final InteractionHand hand;
		private final Vec3 location;

		InteractionAtLocationAction(InteractionHand hand, Vec3 location) {
			this.hand = hand;
			this.location = location;
		}

		private InteractionAtLocationAction(FriendlyByteBuf buffer) {
			this.location = new Vec3(buffer.readFloat(), buffer.readFloat(), buffer.readFloat());
			this.hand = buffer.readEnum(InteractionHand.class);
		}

		@Override
		public ServerboundInteractPacket.ActionType getType() {
			return ServerboundInteractPacket.ActionType.INTERACT_AT;
		}

		@Override
		public void dispatch(ServerboundInteractPacket.Handler handler) {
			handler.onInteraction(this.hand, this.location);
		}

		@Override
		public void write(FriendlyByteBuf buffer) {
			buffer.writeFloat((float)this.location.x);
			buffer.writeFloat((float)this.location.y);
			buffer.writeFloat((float)this.location.z);
			buffer.writeEnum(this.hand);
		}
	}
}