Add spawn_limiter attachment for mob spawners

src/main/java/com/lovetropics/minigames/LoveTropics.java

@@ -47,6 +47,7 @@
 import com.lovetropics.minigames.common.core.diguise.PlayerDisguise;
 import com.lovetropics.minigames.common.core.dimension.RuntimeDimensions;
 import com.lovetropics.minigames.common.core.entity.MinigameEntities;
+import com.lovetropics.minigames.common.core.extension.LimitedSpawnerAttachment;
 import com.lovetropics.minigames.common.core.game.IGameManager;
 import com.lovetropics.minigames.common.core.game.behavior.GameBehaviorTypes;
 import com.lovetropics.minigames.common.core.game.behavior.action.ActionTargetTypes;
@@ -167,6 +168,7 @@ public LoveTropics(IEventBus modBus, ModContainer modContainer) {
         DriftwoodRider.ATTACHMENT_TYPES.register(modBus);
         PlayerDisguise.ATTACHMENT_TYPES.register(modBus);
         ChatChannelStore.ATTACHMENT_TYPES.register(modBus);
+        LimitedSpawnerAttachment.ATTACHMENT_TYPES.register(modBus);
         SoundRegistry.REGISTER.register(modBus);
         MinigameDataComponents.REGISTER.register(modBus);
         BiodiversityBlitz.DATA_COMPONENTS.register(modBus);

src/main/java/com/lovetropics/minigames/common/core/extension/LimitedSpawnerAttachment.java

@@ -0,0 +1,102 @@
+package com.lovetropics.minigames.common.core.extension;
+
+import com.lovetropics.minigames.LoveTropics;
+import com.lovetropics.minigames.mixin.BaseSpawnerAccessor;
+import com.mojang.datafixers.util.Either;
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.UUIDUtil;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.level.BaseSpawner;
+import net.minecraft.world.level.block.entity.BlockEntity;
+import net.neoforged.bus.api.SubscribeEvent;
+import net.neoforged.fml.common.EventBusSubscriber;
+import net.neoforged.neoforge.attachment.AttachmentType;
+import net.neoforged.neoforge.event.entity.living.FinalizeSpawnEvent;
+import net.neoforged.neoforge.event.entity.living.MobSpawnEvent;
+import net.neoforged.neoforge.registries.DeferredRegister;
+import net.neoforged.neoforge.registries.NeoForgeRegistries;
+
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Optional;
+import java.util.Set;
+import java.util.UUID;
+import java.util.function.Supplier;
+
+@EventBusSubscriber(modid = LoveTropics.ID)
+public class LimitedSpawnerAttachment {
+	public static final DeferredRegister<AttachmentType<?>> ATTACHMENT_TYPES = DeferredRegister.create(NeoForgeRegistries.ATTACHMENT_TYPES, LoveTropics.ID);
+
+	public static final Codec<LimitedSpawnerAttachment> CODEC = RecordCodecBuilder.create(i -> i.group(
+			Codec.INT.fieldOf("max_count").forGetter(a -> a.maxCount),
+			UUIDUtil.CODEC_SET.optionalFieldOf("spawned_mobs", Set.of()).forGetter(a -> a.spawnedMobs)
+	).apply(i, (maxCount, spawnedMobs) -> {
+		LimitedSpawnerAttachment attachment = new LimitedSpawnerAttachment(maxCount);
+		attachment.spawnedMobs.addAll(spawnedMobs);
+		return attachment;
+	}));
+
+	public static final Supplier<AttachmentType<LimitedSpawnerAttachment>> ATTACHMENT = ATTACHMENT_TYPES.register(
+			"limited_spawner",
+			() -> AttachmentType.<LimitedSpawnerAttachment>builder(() -> {
+				throw new IllegalStateException("Cannot create default limited_spawner attachment");
+			}).serialize(CODEC).build()
+	);
+
+	private final int maxCount;
+	private final Set<UUID> spawnedMobs = new HashSet<>();
+
+	public LimitedSpawnerAttachment(int maxCount) {
+		this.maxCount = maxCount;
+	}
+
+	@SubscribeEvent
+	public static void onCheckSpawn(MobSpawnEvent.PositionCheck event) {
+		BaseSpawner spawner = event.getSpawner();
+		if (spawner == null || spawner.getOwner() == null) {
+			return;
+		}
+		Either<BlockEntity, Entity> owner = spawner.getOwner();
+		getAttachment(owner).ifPresent(attachment -> {
+			ServerLevel level = event.getLevel().getLevel();
+			if (!attachment.checkCanSpawn(level)) {
+				BlockPos pos = owner.map(BlockEntity::getBlockPos, Entity::blockPosition);
+				((BaseSpawnerAccessor) spawner).invokeDelay(level, pos);
+				event.setResult(MobSpawnEvent.PositionCheck.Result.FAIL);
+			}
+		});
+	}
+
+	@SubscribeEvent
+	public static void onFinalizeSpawn(FinalizeSpawnEvent event) {
+		Either<BlockEntity, Entity> spawner = event.getSpawner();
+		if (spawner != null) {
+			getAttachment(spawner).ifPresent(attachment -> attachment.spawnedMobs.add(event.getEntity().getUUID()));
+		}
+	}
+
+	private static Optional<LimitedSpawnerAttachment> getAttachment(Either<BlockEntity, Entity> spawner) {
+		return spawner.map(
+				blockEntity -> blockEntity.getExistingData(ATTACHMENT),
+				entity -> entity.getExistingData(ATTACHMENT)
+		);
+	}
+
+	private boolean checkCanSpawn(ServerLevel level) {
+		pruneDeadMobs(level);
+		return spawnedMobs.size() < maxCount;
+	}
+
+	private void pruneDeadMobs(ServerLevel level) {
+		Iterator<UUID> iterator = spawnedMobs.iterator();
+		while (iterator.hasNext()) {
+			Entity mob = level.getEntity(iterator.next());
+			if (mob == null || !mob.isAlive()) {
+				iterator.remove();
+			}
+		}
+	}
+}

src/main/java/com/lovetropics/minigames/common/core/extension/package-info.java

@@ -0,0 +1,9 @@
+@MethodsReturnNonnullByDefault
+@ParametersAreNonnullByDefault
+@FieldsAreNonnullByDefault
+package com.lovetropics.minigames.common.core.extension;
+
+import net.minecraft.FieldsAreNonnullByDefault;
+import net.minecraft.MethodsReturnNonnullByDefault;
+
+import javax.annotation.ParametersAreNonnullByDefault;

src/main/java/com/lovetropics/minigames/mixin/BaseSpawnerAccessor.java

@@ -0,0 +1,13 @@
+package com.lovetropics.minigames.mixin;
+
+import net.minecraft.core.BlockPos;
+import net.minecraft.world.level.BaseSpawner;
+import net.minecraft.world.level.Level;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.gen.Invoker;
+
+@Mixin(BaseSpawner.class)
+public interface BaseSpawnerAccessor {
+	@Invoker("delay")
+	void invokeDelay(Level level, BlockPos pos);
+}

src/main/resources/ltminigames.mixins.json

@@ -4,6 +4,7 @@
   "compatibilityLevel": "JAVA_21",
   "plugin": "com.lovetropics.minigames.mixin.LTMixinPlugin",
   "mixins": [
+    "BaseSpawnerAccessor",
     "ChunkStorageMixin",
     "CommonHooksMixin",
     "DataCommandsMixin",