Registry codec extractor (#316)

## Description

- #311 .
- Update the script to cp all the file of the output dir .

## Change to the gradle project

- Adding the fabric API .
- The serveur now need to start starting .

## Test plan

Do the same as before and compare the 1.9.4 output file and my generated
one .

---------

Co-authored-by: Ryan Johnson <ryanj00a@gmail.com>

extractor/build.gradle

@@ -16,8 +16,7 @@ dependencies {
 	minecraft "com.mojang:minecraft:${project.minecraft_version}"
 	mappings "net.fabricmc:yarn:${project.yarn_mappings}:v2"
 	modImplementation "net.fabricmc:fabric-loader:${project.loader_version}"
-
-	// modImplementation "net.fabricmc.fabric-api:fabric-api:${project.fabric_version}"
+	modImplementation "net.fabricmc.fabric-api:fabric-api:${project.fabric_version}"
 }
 
 processResources {

extractor/copy_extractor_output.sh

@@ -2,5 +2,5 @@
 
 cd "$(dirname "$0")" || return
 
-rm ../extracted/*.json
-cp run/valence_extractor_output/*.json ../extracted/
+rm ../extracted/*
+cp run/valence_extractor_output/* ../extracted/

extractor/src/main/java/rs/valence/extractor/Main.java

@@ -2,7 +2,10 @@ package rs.valence.extractor;
 
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonElement;
+import io.netty.handler.codec.EncoderException;
 import net.fabricmc.api.ModInitializer;
+import net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents;
+import net.minecraft.nbt.NbtIo;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import rs.valence.extractor.extractors.*;
@@ -70,8 +73,28 @@ public class Main implements ModInitializer {
             }
         }
 
+        ServerLifecycleEvents.SERVER_STARTING.register(server -> {
+            LOGGER.info("Server starting, Extracting registry codec...");
+            var codecExtractor = new Codec(server);
+
+            try {
+                var out = outputDirectory.resolve(codecExtractor.fileName());
+                var compound = codecExtractor.extract();
+                // read the compound byte-wise and write it to the file
+                try {
+                    NbtIo.write(compound, out.toFile());
+                } catch (IOException var3) {
+                    throw new EncoderException(var3);
+                }
+
+                LOGGER.info("Wrote " + out.toAbsolutePath());
+            } catch (Exception e) {
+                LOGGER.error("Extractor for \"" + codecExtractor.fileName() + "\" failed.", e);
+            }
+
             LOGGER.info("Done.");
-        System.exit(0);
+            server.shutdown();
+        });
     }
 
     public interface Extractor {

extractor/src/main/java/rs/valence/extractor/extractors/Codec.java

@@ -0,0 +1,34 @@
+package rs.valence.extractor.extractors;
+
+import io.netty.handler.codec.EncoderException;
+import net.minecraft.nbt.NbtCompound;
+import net.minecraft.nbt.NbtElement;
+import net.minecraft.nbt.NbtOps;
+import net.minecraft.registry.DynamicRegistryManager;
+import net.minecraft.registry.Registries;
+import net.minecraft.registry.RegistryOps;
+import net.minecraft.registry.SerializableRegistries;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.util.Util;
+
+public class Codec {
+
+    private static final RegistryOps<NbtElement> REGISTRY_OPS= RegistryOps.of(NbtOps.INSTANCE, DynamicRegistryManager.of(Registries.REGISTRIES));
+    private final DynamicRegistryManager.Immutable registryManager;
+
+    public Codec(MinecraftServer server) {
+        this.registryManager = server.getRegistryManager();
+    }
+
+    public String fileName() {
+        return "registry_codec.dat";
+    }
+
+    public NbtCompound extract() {
+        com.mojang.serialization.Codec<DynamicRegistryManager> codec = SerializableRegistries.CODEC;
+        //DynamicRegistryManager.get(net.minecraft.registry.RegistryKey<? extends net.minecraft.registry.Registry<? extends E>>) method.
+
+        NbtElement nbtElement = Util.getResult(codec.encodeStart(REGISTRY_OPS, registryManager), (error) -> new EncoderException("Failed to encode: " + error + " " + registryManager));
+        return (NbtCompound) nbtElement;
+    }
+}