Delete signature & Automatic detect the packet ID

api/src/main/java/moe/caa/multilogin/api/MapperConfigAPI.java

@@ -0,0 +1,10 @@
+package moe.caa.multilogin.api;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+public interface MapperConfigAPI {
+    Map<Integer,Integer> getPacketMapping();
+    void save();
+    void reload();
+}

velocity/src/main/java/fun/ksnb/multilogin/velocity/impl/ChatSessionHandler.java

@@ -0,0 +1,37 @@
+package fun.ksnb.multilogin.velocity.impl;
+
+import com.velocitypowered.api.event.EventManager;
+import com.velocitypowered.api.proxy.Player;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelDuplexHandler;
+import io.netty.channel.ChannelHandlerContext;
+import org.jetbrains.annotations.NotNull;
+
+public class ChatSessionHandler extends ChannelDuplexHandler {
+    private final Player player;
+    private final EventManager eventManager;
+    public ChatSessionHandler(Player player, EventManager eventManager) {
+        this.player = player;
+        this.eventManager = eventManager;
+    }
+
+    @Override
+    public void channelRead(
+            final @NotNull ChannelHandlerContext ctx,
+            final @NotNull Object packet
+    ) throws Exception {
+        if (packet instanceof ByteBuf buffer) {
+            ByteBuf c = buffer.copy();
+            try {
+                int packetId = c.readByte();
+                ProtocolUtils.readUuid(c);
+                ProtocolUtils.readPlayerKey(player.getProtocolVersion(), c);
+                eventManager.fire(new NewChatSessionPacketIDEvent(packetId,player.getProtocolVersion()));
+            } catch (Exception ignore) { } finally {
+                c.resetReaderIndex();
+            }
+        }
+        super.channelRead(ctx, packet);
+    }
+}

velocity/src/main/java/fun/ksnb/multilogin/velocity/impl/NewChatSessionPacketIDEvent.java

@@ -0,0 +1,13 @@
+package fun.ksnb.multilogin.velocity.impl;
+
+import com.velocitypowered.api.network.ProtocolVersion;
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@AllArgsConstructor(access = AccessLevel.PUBLIC)
+@Getter
+public class NewChatSessionPacketIDEvent {
+    private final int packetID;
+    private final ProtocolVersion version;
+}