Allow disconnecting any protocol with a compat codec (#255)

Author: Konicai

bedrock-codec/src/main/java/org/cloudburstmc/protocol/bedrock/codec/compat/BedrockCompat.java

@@ -1,10 +1,14 @@
 package org.cloudburstmc.protocol.bedrock.codec.compat;
 
 import org.cloudburstmc.protocol.bedrock.codec.BedrockCodec;
-import org.cloudburstmc.protocol.bedrock.codec.compat.serializer.DisconnectSerializerCompat;
 import org.cloudburstmc.protocol.bedrock.codec.compat.serializer.LoginSerializerCompat;
 import org.cloudburstmc.protocol.bedrock.codec.compat.serializer.PlayStatusSerializerCompat;
 import org.cloudburstmc.protocol.bedrock.codec.compat.serializer.RequestNetworkSettingsSerializerCompat;
+import org.cloudburstmc.protocol.bedrock.codec.v291.serializer.DisconnectSerializer_v291;
+import org.cloudburstmc.protocol.bedrock.codec.v622.Bedrock_v622;
+import org.cloudburstmc.protocol.bedrock.codec.v622.serializer.DisconnectSerializer_v622;
+import org.cloudburstmc.protocol.bedrock.codec.v712.Bedrock_v712;
+import org.cloudburstmc.protocol.bedrock.codec.v712.serializer.DisconnectSerializer_v712;
 import org.cloudburstmc.protocol.bedrock.data.PacketRecipient;
 import org.cloudburstmc.protocol.bedrock.packet.DisconnectPacket;
 import org.cloudburstmc.protocol.bedrock.packet.LoginPacket;
@@ -14,22 +18,52 @@
 public class BedrockCompat {
     /**
      * This is for servers when figuring out the protocol of a client joining.
+     * Certain protocols that are older will need to use {@link #disconnectCompat(int)} before disconnecting,
+     * in order for the client to see a proper disconnect message.
      */
     public static BedrockCodec CODEC = BedrockCodec.builder()
             .helper(() -> NoopBedrockCodecHelper.INSTANCE)
             .registerPacket(LoginPacket::new, LoginSerializerCompat.INSTANCE, 1, PacketRecipient.SERVER)
             .registerPacket(PlayStatusPacket::new, PlayStatusSerializerCompat.INSTANCE, 2, PacketRecipient.CLIENT)
-            .registerPacket(DisconnectPacket::new, new DisconnectSerializerCompat(true), 5, PacketRecipient.BOTH)
+            .registerPacket(DisconnectPacket::new, DisconnectSerializer_v712.INSTANCE, 5, PacketRecipient.BOTH)
             .registerPacket(RequestNetworkSettingsPacket::new, RequestNetworkSettingsSerializerCompat.INSTANCE, 193, PacketRecipient.SERVER)
             .protocolVersion(0)
             .minecraftVersion("0.0.0")
             .build();
 
     /**
-     * This is legacy version of the compat codec which does not use DisconnectFailReason in DisconnectPacket.
-     * Use this for servers that do not support Minecraft: Bedrock Edition 1.20.40 and above.
+     * A legacy version of the compat codec which does not use DisconnectFailReason in DisconnectPacket.
+     * Use this for protocols lower than v622
      */
-    public static BedrockCodec CODEC_LEGACY = CODEC.toBuilder()
-            .updateSerializer(DisconnectPacket.class, new DisconnectSerializerCompat(false))
+    public static BedrockCodec CODEC_v291 = CODEC.toBuilder()
+            .updateSerializer(DisconnectPacket.class, DisconnectSerializer_v291.INSTANCE)
             .build();
+
+    /**
+     * A legacy version of the compat codec which does not use filteredMessage in DisconnectPacket.
+     * Use this for protocols equal to or greater than v622, but less than v712
+     */
+    public static BedrockCodec CODEC_v622 = CODEC.toBuilder()
+            .updateSerializer(DisconnectPacket.class, DisconnectSerializer_v622.INSTANCE)
+            .build();
+
+    /**
+     * Certain older protocols have outdated {@link DisconnectPacket} formats.
+     * Using the codec provided by this method before disconnecting a client will always
+     * ensure they receive a well-formed DisconnectPacket.
+     * <p>
+     * Note that this compat codec should only be used if disconnecting the client upon receiving
+     * its protocol version. Otherwise, use a proper codec that targets the specific protocol.
+     *
+     * @param protocolVersion the client's protocol version
+     * @return a compat codec suitable for disconnecting
+     */
+    public static BedrockCodec disconnectCompat(int protocolVersion) {
+        if (protocolVersion < Bedrock_v622.CODEC.getProtocolVersion()) {
+            return CODEC_v291;
+        } else if (protocolVersion < Bedrock_v712.CODEC.getProtocolVersion()) {
+            return CODEC_v622;
+        }
+        return CODEC; // v712 or above
+    }
 }