Now understands forge packets

src/main/java/org/adde0109/ambassador/forge/packet/ACKPacket.java

@@ -1,5 +1,6 @@
 package org.adde0109.ambassador.forge.packet;
 
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 
@@ -12,7 +13,11 @@ public class ACKPacket implements IForgeLoginWrapperPacket<Context.ClientContext
     }
     @Override
     public ByteBuf encode() {
-        return Unpooled.EMPTY_BUFFER;
+        ByteBuf buf = Unpooled.buffer();
+
+        ProtocolUtils.writeVarInt(buf, 99);
+
+        return buf;
     }
 
     @Override

src/main/java/org/adde0109/ambassador/forge/packet/ConfigDataPacket.java

@@ -1,18 +1,39 @@
 package org.adde0109.ambassador.forge.packet;
 
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
 
 public class ConfigDataPacket implements IForgeLoginWrapperPacket<Context> {
 
+    private final String fileName;
+    private final byte[] fileData;
+
     private final Context context;
 
-    public ConfigDataPacket(Context context) {
+    public ConfigDataPacket(String fileName, byte[] fileData, Context context) {
+        this.fileName = fileName;
+        this.fileData = fileData;
         this.context = context;
     }
 
+    public static ConfigDataPacket read(ByteBuf input, Context context, boolean FML3) {
+        String registryName = ProtocolUtils.readString(input);
+        byte[] snapshot = ProtocolUtils.readByteArray(input);
+
+        return new ConfigDataPacket(registryName, snapshot, context);
+    }
+
     @Override
     public ByteBuf encode() {
-        return null;
+        ByteBuf buf = Unpooled.buffer();
+
+        ProtocolUtils.writeVarInt(buf, 4);
+
+        ProtocolUtils.writeString(buf, fileName);
+        ProtocolUtils.writeByteArray(buf, fileData);
+
+        return buf;
     }
 
     @Override

src/main/java/org/adde0109/ambassador/forge/packet/GenericForgeLoginWrapperPacket.java

@@ -1,14 +1,12 @@
 package org.adde0109.ambassador.forge.packet;
 
-import com.velocitypowered.proxy.protocol.packet.LoginPluginResponse;
 import com.velocitypowered.proxy.protocol.util.DeferredByteBufHolder;
 import io.netty.buffer.ByteBuf;
 
 public class GenericForgeLoginWrapperPacket<T extends Context> extends DeferredByteBufHolder implements IForgeLoginWrapperPacket<T> {
-
   private final T context;
 
-  private GenericForgeLoginWrapperPacket(ByteBuf input, T context) {
+  GenericForgeLoginWrapperPacket(ByteBuf input, T context) {
     super(input);
     this.context = context;
   }

src/main/java/org/adde0109/ambassador/forge/packet/ModDataPacket.java

@@ -0,0 +1,9 @@
+package org.adde0109.ambassador.forge.packet;
+
+import io.netty.buffer.ByteBuf;
+
+public class ModDataPacket extends GenericForgeLoginWrapperPacket<Context> {
+  ModDataPacket(ByteBuf input, Context context) {
+    super(input, context);
+  }
+}

src/main/java/org/adde0109/ambassador/forge/packet/ModListPacket.java

@@ -79,12 +79,7 @@ public class ModListPacket implements IForgeLoginWrapperPacket<Context> {
             dataPackRegistries.forEach(k -> ProtocolUtils.writeString(buf, k));
         }
 
-        ByteBuf output = Unpooled.buffer();
+        return buf;
-        ProtocolUtils.writeString(output, "fml:handshake");
-        ProtocolUtils.writeVarInt(output, buf.readableBytes());
-        output.writeBytes(buf);
-
-        return output;
     }
 
     @Override

src/main/java/org/adde0109/ambassador/forge/packet/ModListReplyPacket.java

@@ -69,12 +69,7 @@ public class ModListReplyPacket implements IForgeLoginWrapperPacket<Context.Clie
       ProtocolUtils.writeString(buf, v);
     });
 
-    ByteBuf output = Unpooled.buffer();
+    return buf;
-    ProtocolUtils.writeString(output, "fml:handshake");
-    ProtocolUtils.writeVarInt(output, buf.readableBytes());
-    output.writeBytes(buf);
-
-    return output;
   }
 
   @Override

src/main/java/org/adde0109/ambassador/forge/packet/RegistryPacket.java

@@ -1,17 +1,47 @@
 package org.adde0109.ambassador.forge.packet;
 
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
 
 public class RegistryPacket implements IForgeLoginWrapperPacket<Context> {
 
+  private final String registryName;
+  private final byte[] snapshot;
+
   private final Context context;
-  public RegistryPacket(Context context) {
+  public RegistryPacket(String registryName, byte[] snapshot, Context context) {
+    this.registryName = registryName;
+    this.snapshot = snapshot;
     this.context = context;
   }
 
+  public static RegistryPacket read(ByteBuf input, Context context, boolean FML3) {
+    String registryName = ProtocolUtils.readString(input);
+    byte[] snapshot = null;
+    if (input.readBoolean()) {
+      snapshot = new byte[input.readableBytes()];
+      input.readBytes(snapshot);
+    }
+
+    return new RegistryPacket(registryName, snapshot, context);
+  }
+
   @Override
   public ByteBuf encode() {
-    return null;
+    ByteBuf buf = Unpooled.buffer();
+
+    ProtocolUtils.writeVarInt(buf, 3);
+
+    ProtocolUtils.writeString(buf, registryName);
+    if (snapshot != null) {
+      buf.writeBoolean(true);
+      buf.writeBytes(snapshot);
+    } else {
+      buf.writeBoolean(false);
+    }
+
+    return buf;
   }
 
   @Override

src/main/java/org/adde0109/ambassador/forge/pipeline/ForgeLoginWrapperCodec.java

@@ -5,6 +5,7 @@ import com.velocitypowered.proxy.protocol.packet.LoginPluginMessage;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginResponse;
 import com.velocitypowered.proxy.protocol.util.DeferredByteBufHolder;
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.DecoderException;
 import io.netty.handler.codec.MessageToMessageCodec;
@@ -29,7 +30,7 @@ public class ForgeLoginWrapperCodec extends MessageToMessageCodec<DeferredByteBu
     Context context;
     if (in instanceof LoginPluginMessage msg && msg.getChannel().equals("fml:loginwrapper")) {
       context = Context.createContext(msg.getId());
-    } else if (in instanceof LoginPluginResponse msg && loginWrapperIDs.remove(msg.getId()) != null) {
+    } else if (in instanceof LoginPluginResponse msg && loginWrapperIDs.remove(Integer.valueOf(msg.getId()))) {
       context = Context.createContext(msg.getId(), msg.isSuccess());
     } else {
       return;
@@ -50,6 +51,7 @@ public class ForgeLoginWrapperCodec extends MessageToMessageCodec<DeferredByteBu
               break;
             case 99:
               out.add(new ACKPacket(clientContext));
+              break;
             default:
               throw new DecoderException();
           }
@@ -59,11 +61,17 @@ public class ForgeLoginWrapperCodec extends MessageToMessageCodec<DeferredByteBu
               out.add(ModListPacket.read(buf, context, FML3));
               break;
             case 3:
-              out.add(new RegistryPacket(context));
+              out.add(RegistryPacket.read(buf, context, FML3));
               break;
             case 4:
-              out.add(new ConfigDataPacket(context));
+              out.add(ConfigDataPacket.read(buf, context, FML3));
               break;
+            case 5:
+              if (FML3) {
+                buf.readerIndex(originalReaderIndex);
+                out.add(ModDataPacket.create(buf.retain(), context));
+                break;
+              }
             default:
               throw new DecoderException();
           }
@@ -77,11 +85,24 @@ public class ForgeLoginWrapperCodec extends MessageToMessageCodec<DeferredByteBu
 
   @Override
   protected void encode(ChannelHandlerContext ctx, IForgeLoginWrapperPacket<?> msg, List<Object> out) throws Exception {
-    if (msg.getContext() instanceof Context.ClientContext clientContext) {
+    ByteBuf wrapped;
-      out.add(new LoginPluginResponse(clientContext.getResponseID(), clientContext.success(), msg.encode()));
+    if (msg instanceof GenericForgeLoginWrapperPacket<?>) {
+      wrapped = msg.encode();
     } else {
-      out.add(new LoginPluginMessage(msg.getContext().getResponseID(), "fml:loginwrapper", msg.encode()));
+      wrapped = Unpooled.buffer();
-      this.loginWrapperIDs.add(msg.getContext().getResponseID());
+      ByteBuf encoded = msg.encode();
+      ProtocolUtils.writeString(wrapped, "fml:handshake");
+      ProtocolUtils.writeVarInt(wrapped, encoded.readableBytes());
+      wrapped.writeBytes(encoded);
+    }
+
+    if (msg.getContext() instanceof Context.ClientContext clientContext) {
+      out.add(new LoginPluginResponse(clientContext.getResponseID(), clientContext.success(), wrapped));
+    } else {
+      out.add(new LoginPluginMessage(msg.getContext().getResponseID(), "fml:loginwrapper", wrapped));
+      if (!(msg instanceof ModDataPacket)) {
+        this.loginWrapperIDs.add(msg.getContext().getResponseID());
+      }
     }
   }
 }