Initial project setup for SilkSpawners mod

Add SilkSpawners mod source files, configuration, mixins, Gradle build scripts, and metadata for Fabric. Implements spawner drop logic, config loading/saving, and required interfaces/mixins for custom spawner behavior.

src/main/java/com/kasetoatz/silkspawners/SilkSpawners.java

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+package com.kasetoatz.silkspawners;
+
+import net.fabricmc.api.ModInitializer;
+
+import static com.kasetoatz.silkspawners.config.Config.load;
+
+public class SilkSpawners implements ModInitializer
+{
+    @Override
+    public void onInitialize()
+    {
+        load();
+    }
+}

src/main/java/com/kasetoatz/silkspawners/accessors/IMobSpawnerLogic.java

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+package com.kasetoatz.silkspawners.accessors;
+
+import net.minecraft.entity.EntityType;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.random.Random;
+import net.minecraft.world.World;
+
+public interface IMobSpawnerLogic
+{
+    EntityType<?> silkspawners$getEntityType(World world, Random random, BlockPos pos);
+}

src/main/java/com/kasetoatz/silkspawners/accessors/ITrialSpawnerLogic.java

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+package com.kasetoatz.silkspawners.accessors;
+
+import net.minecraft.block.spawner.TrialSpawnerLogic;
+
+public interface ITrialSpawnerLogic
+{
+    TrialSpawnerLogic.FullConfig silkspawners$getFullConfig();
+}

src/main/java/com/kasetoatz/silkspawners/config/Config.java

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+package com.kasetoatz.silkspawners.config;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonObject;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.util.crash.CrashException;
+import net.minecraft.util.crash.CrashReport;
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+
+public class Config
+{
+    public static boolean ENABLE_SPAWNER = true;
+    public static boolean ENABLE_TRIAL_SPAWNER = true;
+    public static boolean REQUIRE_PICKAXE = true;
+    public static boolean REQUIRE_SILK_TOUCH = true;
+
+    private static final File config = new File(MinecraftClient.getInstance().runDirectory, "config/silkspawners.json");
+    private static final Gson gson = new GsonBuilder().setPrettyPrinting().create();
+
+    public static void load()
+    {
+        if (!config.exists())
+        {
+            save();
+            return;
+        }
+        try (FileReader reader = new FileReader(config))
+        {
+            JsonObject json = gson.fromJson(reader, JsonObject.class);
+            if (json.has("enable-spawner"))
+            {
+                ENABLE_SPAWNER = json.get("enable-spawner").getAsBoolean();
+            }
+            if (json.has("enable-trial-spawner"))
+            {
+                ENABLE_TRIAL_SPAWNER = json.get("enable-trial-spawner").getAsBoolean();
+            }
+            if (json.has("require-pickaxe"))
+            {
+                REQUIRE_PICKAXE = json.get("require-pickaxe").getAsBoolean();
+            }
+            if (json.has("require-silk-touch"))
+            {
+                REQUIRE_SILK_TOUCH = json.get("require-silk-touch").getAsBoolean();
+            }
+            save();
+        }
+        catch (IOException exc)
+        {
+            throw new CrashException(CrashReport.create(exc, "Loading config file."));
+        }
+    }
+
+    public static void save()
+    {
+        JsonObject json = new JsonObject();
+        json.addProperty("enable-spawner", ENABLE_SPAWNER);
+        json.addProperty("enable-trial-spawner", ENABLE_TRIAL_SPAWNER);
+        json.addProperty("require-pickaxe", REQUIRE_PICKAXE);
+        json.addProperty("require-silk-touch", REQUIRE_SILK_TOUCH);
+        try (FileWriter writer = new FileWriter(config))
+        {
+            gson.toJson(json, writer);
+        }
+        catch (IOException exc)
+        {
+            throw new CrashException(CrashReport.create(exc, "Saving config file."));
+        }
+    }
+}

src/main/java/com/kasetoatz/silkspawners/mixin/BlockMixin.java

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+package com.kasetoatz.silkspawners.mixin;
+
+import com.kasetoatz.silkspawners.accessors.IMobSpawnerLogic;
+import com.kasetoatz.silkspawners.accessors.ITrialSpawnerLogic;
+import net.minecraft.block.*;
+import net.minecraft.block.entity.BlockEntity;
+import net.minecraft.block.entity.MobSpawnerBlockEntity;
+import net.minecraft.block.entity.Spawner;
+import net.minecraft.block.entity.TrialSpawnerBlockEntity;
+import net.minecraft.block.spawner.TrialSpawnerLogic;
+import net.minecraft.component.DataComponentTypes;
+import net.minecraft.component.type.NbtComponent;
+import net.minecraft.enchantment.EnchantmentHelper;
+import net.minecraft.enchantment.Enchantments;
+import net.minecraft.entity.Entity;
+import net.minecraft.entity.EntityType;
+import net.minecraft.item.ItemStack;
+import net.minecraft.registry.RegistryKeys;
+import net.minecraft.registry.tag.ItemTags;
+import net.minecraft.server.world.ServerWorld;
+import net.minecraft.util.math.BlockPos;
+import org.jspecify.annotations.Nullable;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Redirect;
+
+import java.util.List;
+import java.util.Objects;
+
+import static com.kasetoatz.silkspawners.config.Config.*;
+
+@Mixin(Block.class)
+public class BlockMixin
+{
+    @Redirect(method="dropStacks(Lnet/minecraft/block/BlockState;Lnet/minecraft/world/World;Lnet/minecraft/util/math/BlockPos;Lnet/minecraft/block/entity/BlockEntity;Lnet/minecraft/entity/Entity;Lnet/minecraft/item/ItemStack;)V", at=@At(value="INVOKE", target="Lnet/minecraft/block/Block;getDroppedStacks(Lnet/minecraft/block/BlockState;Lnet/minecraft/server/world/ServerWorld;Lnet/minecraft/util/math/BlockPos;Lnet/minecraft/block/entity/BlockEntity;Lnet/minecraft/entity/Entity;Lnet/minecraft/item/ItemStack;)Ljava/util/List;"))
+    private static List<ItemStack> getDroppedStacks(BlockState state, ServerWorld world, BlockPos pos, @Nullable BlockEntity blockEntity, @Nullable Entity entity, ItemStack stack)
+    {
+        System.out.println(stack);
+        if (!(blockEntity instanceof Spawner))
+        {
+            return getDroppedStacks(state, world, pos, blockEntity, entity, stack);
+        }
+        if (!ENABLE_SPAWNER && state.getBlock() instanceof SpawnerBlock)
+        {
+            return List.of();
+        }
+        if (!ENABLE_TRIAL_SPAWNER && state.getBlock() instanceof TrialSpawnerBlock)
+        {
+            return List.of();
+        }
+        if (REQUIRE_PICKAXE && !stack.isIn(ItemTags.PICKAXES))
+        {
+            return List.of();
+        }
+        if (REQUIRE_SILK_TOUCH && EnchantmentHelper.getLevel(world.getRegistryManager().getOrThrow(RegistryKeys.ENCHANTMENT).getOrThrow(Enchantments.SILK_TOUCH), stack) < 1)
+        {
+            return List.of();
+        }
+        ItemStack item = state.getBlock().asItem().getDefaultStack();
+        NbtComponent component = Objects.requireNonNullElse(item.get(DataComponentTypes.CUSTOM_DATA), NbtComponent.DEFAULT);
+        if (blockEntity instanceof MobSpawnerBlockEntity spawner)
+        {
+            EntityType<?> type = ((IMobSpawnerLogic)spawner.getLogic()).silkspawners$getEntityType(world, world.getRandom(), pos);
+            if (type != null)
+            {
+                component.apply(nbtCompound -> nbtCompound.put("entityType", EntityType.CODEC, type));
+            }
+
+        }
+        else if (blockEntity instanceof TrialSpawnerBlockEntity trialSpawner)
+        {
+            component.apply(nbtCompound -> nbtCompound.put("fullConfig", TrialSpawnerLogic.FullConfig.CODEC.codec(), ((ITrialSpawnerLogic)(Object)trialSpawner.getSpawner()).silkspawners$getFullConfig()));
+        }
+        item.set(DataComponentTypes.CUSTOM_DATA, component);
+        return List.of(item);
+    }
+}

src/main/java/com/kasetoatz/silkspawners/mixin/MobSpawnerLogicMixin.java

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+package com.kasetoatz.silkspawners.mixin;
+
+import com.kasetoatz.silkspawners.accessors.IMobSpawnerLogic;
+import net.minecraft.block.spawner.MobSpawnerEntry;
+import net.minecraft.block.spawner.MobSpawnerLogic;
+import net.minecraft.entity.EntityType;
+import net.minecraft.registry.Registries;
+import net.minecraft.util.Identifier;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.random.Random;
+import net.minecraft.world.World;
+import org.jspecify.annotations.Nullable;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+
+@Mixin(MobSpawnerLogic.class)
+public abstract class MobSpawnerLogicMixin implements IMobSpawnerLogic
+{
+    @Shadow protected abstract MobSpawnerEntry getSpawnEntry(@Nullable World world, net.minecraft.util.math.random.Random random, BlockPos pos);
+
+    public EntityType<?> silkspawners$getEntityType(World world, Random random, BlockPos pos)
+    {
+        return getSpawnEntry(world, random, pos).getNbt().getString("id").map(id -> Registries.ENTITY_TYPE.get(Identifier.of(id))).orElse(null);
+    }
+}

src/main/java/com/kasetoatz/silkspawners/mixin/TrialSpawnerLogicMixin.java

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+package com.kasetoatz.silkspawners.mixin;
+
+import com.kasetoatz.silkspawners.accessors.ITrialSpawnerLogic;
+import net.minecraft.block.spawner.TrialSpawnerLogic;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+
+@Mixin(TrialSpawnerLogic.class)
+public class TrialSpawnerLogicMixin implements ITrialSpawnerLogic
+{
+    @Shadow private TrialSpawnerLogic.FullConfig fullConfig;
+
+    @Override
+    public TrialSpawnerLogic.FullConfig silkspawners$getFullConfig()
+    {
+        return fullConfig;
+    }
+}

src/main/resources/fabric.mod.json

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+{
+  "schemaVersion": 1,
+  "id": "silkspawners",
+  "version": "${version}",
+  "name": "SilkSpawners",
+  "description": "",
+  "authors": [],
+  "contact": {},
+  "license": "MIT",
+  "icon": "assets/silkspawners/icon.png",
+  "environment": "*",
+  "entrypoints": {
+    "main": [
+      "com.kasetoatz.silkspawners.SilkSpawners"
+    ]
+  },
+  "mixins": [
+    "silkspawners.mixins.json"
+  ],
+  "depends": {
+    "fabricloader": ">=${loader_version}",
+    "fabric-api": "*",
+    "minecraft": "${minecraft_version}"
+  }
+}

src/main/resources/silkspawners.mixins.json

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+{
+  "required": true,
+  "minVersion": "0.8",
+  "package": "com.kasetoatz.silkspawners.mixin",
+  "compatibilityLevel": "JAVA_21",
+  "mixins": [
+    "BlockMixin",
+    "MobSpawnerLogicMixin",
+    "TrialSpawnerLogicMixin"
+  ],
+  "client": [
+  ],
+  "injectors": {
+    "defaultRequire": 1
+  },
+  "overwrites": {
+    "requireAnnotations": true
+  }
+}