feat(registry): metatag datagen provider

specter-debug/src/main/java/dev/spiritstudios/specter/impl/debug/command/MetatagCommand.java

@@ -9,8 +9,8 @@
 import com.mojang.serialization.Codec;
 import com.mojang.serialization.JsonOps;
 import dev.spiritstudios.specter.api.registry.metatag.Metatag;
+import dev.spiritstudios.specter.api.registry.metatag.data.MetatagResource;
 import dev.spiritstudios.specter.impl.registry.metatag.MetatagHolder;
-import dev.spiritstudios.specter.impl.registry.metatag.data.MetatagResource;
 import net.minecraft.command.CommandSource;
 import net.minecraft.command.argument.IdentifierArgumentType;
 import net.minecraft.registry.Registries;

specter-registry/src/main/java/dev/spiritstudios/specter/impl/registry/metatag/data/MetatagResource.java → specter-registry/src/main/java/dev/spiritstudios/specter/api/registry/metatag/data/MetatagResource.java

@@ -1,4 +1,4 @@
-package dev.spiritstudios.specter.impl.registry.metatag.data;
+package dev.spiritstudios.specter.api.registry.metatag.data;
 
 import com.mojang.datafixers.util.Pair;
 import com.mojang.serialization.Codec;

specter-registry/src/main/java/dev/spiritstudios/specter/api/registry/metatag/datagen/MetatagProvider.java

@@ -0,0 +1,108 @@
+package dev.spiritstudios.specter.api.registry.metatag.datagen;
+
+import com.google.gson.JsonElement;
+import com.mojang.datafixers.util.Pair;
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.DynamicOps;
+import com.mojang.serialization.JsonOps;
+import dev.spiritstudios.specter.api.registry.metatag.Metatag;
+import dev.spiritstudios.specter.api.registry.metatag.data.MetatagResource;
+import it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap;
+import net.fabricmc.fabric.api.datagen.v1.FabricDataOutput;
+import net.minecraft.data.DataOutput;
+import net.minecraft.data.DataProvider;
+import net.minecraft.data.DataWriter;
+import net.minecraft.registry.RegistryOps;
+import net.minecraft.registry.RegistryWrapper;
+import net.minecraft.util.Identifier;
+
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Consumer;
+
+public abstract class MetatagProvider<R> implements DataProvider {
+	protected final CompletableFuture<RegistryWrapper.WrapperLookup> registriesFuture;
+	protected final FabricDataOutput dataOutput;
+	protected final DataOutput.OutputType outputType;
+
+	protected MetatagProvider(FabricDataOutput dataOutput, CompletableFuture<RegistryWrapper.WrapperLookup> registriesFuture, DataOutput.OutputType outputType) {
+		this.dataOutput = dataOutput;
+		this.registriesFuture = registriesFuture;
+		this.outputType = outputType;
+	}
+
+	@Override
+	public CompletableFuture<?> run(DataWriter writer) {
+		return this.registriesFuture.thenCompose(lookup -> {
+			DataOutput.PathResolver pathResolver = dataOutput.getResolver(outputType, "metatags");
+			DynamicOps<JsonElement> ops = RegistryOps.of(JsonOps.INSTANCE, lookup);
+
+			List<MetatagBuilder<R, ?>> metatags = new ArrayList<>();
+			configure(metatags::add, lookup);
+
+			return CompletableFuture.allOf(metatags.stream()
+				.map(builder -> generate(builder, pathResolver, writer, ops))
+				.toArray(CompletableFuture[]::new));
+		});
+	}
+
+	private <V> CompletableFuture<?> generate(MetatagBuilder<R, V> builder, DataOutput.PathResolver pathResolver, DataWriter writer, DynamicOps<JsonElement> ops) {
+		return CompletableFuture.supplyAsync(() -> {
+			Codec<MetatagResource<V>> resourceCodec = MetatagResource.resourceCodecOf(builder.metatag);
+			return resourceCodec.encodeStart(ops, builder.build())
+				.getOrThrow(error -> {
+					throw new IllegalStateException("Failed to encode metatag resource: " + error);
+				});
+		}).thenComposeAsync(encoded -> {
+			Identifier registryId = builder.metatag.getRegistry().getKey().getValue();
+			Path metatagPath = pathResolver.resolveJson(builder.metatag.getId().withPrefixedPath(registryId.getNamespace() + "/" + registryId.getPath() + "/"));
+
+			return DataProvider.writeToPath(writer, encoded, metatagPath);
+		});
+	}
+
+	protected abstract void configure(Consumer<MetatagBuilder<R, ?>> provider, RegistryWrapper.WrapperLookup lookup);
+
+	protected final <V> MetatagBuilder<R, V> create(Metatag<R, V> metatag) {
+		return new MetatagBuilder<>(metatag, false);
+	}
+
+	protected final <V> MetatagBuilder<R, V> create(Metatag<R, V> metatag, boolean replace) {
+		return new MetatagBuilder<>(metatag, replace);
+	}
+
+	@Override
+	public String getName() {
+		return "Metatags";
+	}
+
+	protected static final class MetatagBuilder<R, V> {
+		private final Metatag<R, V> metatag;
+		private final Map<R, V> values = new Object2ObjectOpenHashMap<>();
+		private final boolean replace;
+
+		private MetatagBuilder(Metatag<R, V> metatag, boolean replace) {
+			this.metatag = metatag;
+			this.replace = replace;
+		}
+
+		public MetatagBuilder<R, V> put(R value, V metatagValue) {
+			this.values.put(value, metatagValue);
+			return this;
+		}
+
+		private MetatagResource<V> build() {
+			return new MetatagResource<>(
+				replace,
+				values.entrySet().stream()
+					.map(entry -> Pair.of(metatag.getRegistry().getId(entry.getKey()), entry.getValue()))
+					.filter(pair -> Objects.nonNull(pair.getFirst()))
+					.toList()
+			);
+		}
+	}
+}

specter-registry/src/main/java/dev/spiritstudios/specter/impl/registry/metatag/data/MetatagMap.java

@@ -5,6 +5,7 @@
 import com.mojang.serialization.Codec;
 import com.mojang.serialization.JsonOps;
 import dev.spiritstudios.specter.api.registry.metatag.Metatag;
+import dev.spiritstudios.specter.api.registry.metatag.data.MetatagResource;
 import it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap;
 import net.minecraft.registry.Registry;
 import net.minecraft.resource.Resource;