minecraft-src/net/minecraft/world/item/SpawnEggItem.java

package net.minecraft.world.item;

import com.google.common.collect.Iterables;
import com.google.common.collect.Maps;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.core.HolderLookup;
import net.minecraft.core.component.DataComponents;
import net.minecraft.core.registries.Registries;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.stats.Stats;
import net.minecraft.world.InteractionHand;
import net.minecraft.world.InteractionResult;
import net.minecraft.world.entity.AgeableMob;
import net.minecraft.world.entity.Entity;
import net.minecraft.world.entity.EntitySpawnReason;
import net.minecraft.world.entity.EntityType;
import net.minecraft.world.entity.Mob;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.flag.FeatureFlagSet;
import net.minecraft.world.item.component.CustomData;
import net.minecraft.world.item.context.UseOnContext;
import net.minecraft.world.level.ClipContext;
import net.minecraft.world.level.Level;
import net.minecraft.world.level.Spawner;
import net.minecraft.world.level.block.LiquidBlock;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.gameevent.GameEvent;
import net.minecraft.world.phys.BlockHitResult;
import net.minecraft.world.phys.HitResult;
import net.minecraft.world.phys.Vec3;
import org.jetbrains.annotations.Nullable;

public class SpawnEggItem extends Item {
	private static final Map<EntityType<? extends Mob>, SpawnEggItem> BY_ID = Maps.<EntityType<? extends Mob>, SpawnEggItem>newIdentityHashMap();
	private final EntityType<?> defaultType;

	public SpawnEggItem(EntityType<? extends Mob> defaultType, Item.Properties properties) {
		super(properties);
		this.defaultType = defaultType;
		BY_ID.put(defaultType, this);
	}

	@Override
	public InteractionResult useOn(UseOnContext context) {
		Level level = context.getLevel();
		if (level.isClientSide) {
			return InteractionResult.SUCCESS;
		} else {
			ItemStack itemStack = context.getItemInHand();
			BlockPos blockPos = context.getClickedPos();
			Direction direction = context.getClickedFace();
			BlockState blockState = level.getBlockState(blockPos);
			if (level.getBlockEntity(blockPos) instanceof Spawner spawner) {
				EntityType<?> entityType = this.getType(level.registryAccess(), itemStack);
				spawner.setEntityId(entityType, level.getRandom());
				level.sendBlockUpdated(blockPos, blockState, blockState, 3);
				level.gameEvent(context.getPlayer(), GameEvent.BLOCK_CHANGE, blockPos);
				itemStack.shrink(1);
				return InteractionResult.SUCCESS;
			} else {
				BlockPos blockPos2;
				if (blockState.getCollisionShape(level, blockPos).isEmpty()) {
					blockPos2 = blockPos;
				} else {
					blockPos2 = blockPos.relative(direction);
				}

				EntityType<?> entityType = this.getType(level.registryAccess(), itemStack);
				if (entityType.spawn(
						(ServerLevel)level,
						itemStack,
						context.getPlayer(),
						blockPos2,
						EntitySpawnReason.SPAWN_ITEM_USE,
						true,
						!Objects.equals(blockPos, blockPos2) && direction == Direction.UP
					)
					!= null) {
					itemStack.shrink(1);
					level.gameEvent(context.getPlayer(), GameEvent.ENTITY_PLACE, blockPos);
				}

				return InteractionResult.SUCCESS;
			}
		}
	}

	@Override
	public InteractionResult use(Level level, Player player, InteractionHand hand) {
		ItemStack itemStack = player.getItemInHand(hand);
		BlockHitResult blockHitResult = getPlayerPOVHitResult(level, player, ClipContext.Fluid.SOURCE_ONLY);
		if (blockHitResult.getType() != HitResult.Type.BLOCK) {
			return InteractionResult.PASS;
		} else if (level instanceof ServerLevel serverLevel) {
			BlockPos blockPos = blockHitResult.getBlockPos();
			if (!(level.getBlockState(blockPos).getBlock() instanceof LiquidBlock)) {
				return InteractionResult.PASS;
			} else if (level.mayInteract(player, blockPos) && player.mayUseItemAt(blockPos, blockHitResult.getDirection(), itemStack)) {
				EntityType<?> entityType = this.getType(serverLevel.registryAccess(), itemStack);
				Entity entity = entityType.spawn(serverLevel, itemStack, player, blockPos, EntitySpawnReason.SPAWN_ITEM_USE, false, false);
				if (entity == null) {
					return InteractionResult.PASS;
				} else {
					itemStack.consume(1, player);
					player.awardStat(Stats.ITEM_USED.get(this));
					level.gameEvent(player, GameEvent.ENTITY_PLACE, entity.position());
					return InteractionResult.SUCCESS;
				}
			} else {
				return InteractionResult.FAIL;
			}
		} else {
			return InteractionResult.SUCCESS;
		}
	}

	public boolean spawnsEntity(HolderLookup.Provider registries, ItemStack stack, EntityType<?> entityType) {
		return Objects.equals(this.getType(registries, stack), entityType);
	}

	@Nullable
	public static SpawnEggItem byId(@Nullable EntityType<?> type) {
		return (SpawnEggItem)BY_ID.get(type);
	}

	public static Iterable<SpawnEggItem> eggs() {
		return Iterables.unmodifiableIterable(BY_ID.values());
	}

	public EntityType<?> getType(HolderLookup.Provider registries, ItemStack provider) {
		CustomData customData = provider.getOrDefault(DataComponents.ENTITY_DATA, CustomData.EMPTY);
		if (!customData.isEmpty()) {
			EntityType<?> entityType = customData.parseEntityType(registries, Registries.ENTITY_TYPE);
			if (entityType != null) {
				return entityType;
			}
		}

		return this.defaultType;
	}

	@Override
	public FeatureFlagSet requiredFeatures() {
		return this.defaultType.requiredFeatures();
	}

	public Optional<Mob> spawnOffspringFromSpawnEgg(
		Player player, Mob mob, EntityType<? extends Mob> entityType, ServerLevel serverLevel, Vec3 pos, ItemStack stack
	) {
		if (!this.spawnsEntity(serverLevel.registryAccess(), stack, entityType)) {
			return Optional.empty();
		} else {
			Mob mob2;
			if (mob instanceof AgeableMob) {
				mob2 = ((AgeableMob)mob).getBreedOffspring(serverLevel, (AgeableMob)mob);
			} else {
				mob2 = entityType.create(serverLevel, EntitySpawnReason.SPAWN_ITEM_USE);
			}

			if (mob2 == null) {
				return Optional.empty();
			} else {
				mob2.setBaby(true);
				if (!mob2.isBaby()) {
					return Optional.empty();
				} else {
					mob2.snapTo(pos.x(), pos.y(), pos.z(), 0.0F, 0.0F);
					mob2.applyComponentsFromItemStack(stack);
					serverLevel.addFreshEntityWithPassengers(mob2);
					stack.consume(1, player);
					return Optional.of(mob2);
				}
			}
		}
	}

	@Override
	public boolean shouldPrintOpWarning(ItemStack stack, @Nullable Player player) {
		if (player != null && player.getPermissionLevel() >= 2) {
			CustomData customData = stack.get(DataComponents.ENTITY_DATA);
			if (customData != null) {
				EntityType<?> entityType = customData.parseEntityType(player.level().registryAccess(), Registries.ENTITY_TYPE);
				return entityType != null && entityType.onlyOpCanSetNbt();
			}
		}

		return false;
	}
}