Fix Via support; consolidate module code

ViaFabric support tested on 1.21.4 server. 1.20.2+ clients work. ViaFabric breaks with 1.20.1 clients on 1.21.4 servers, with the connection timing out. This is a Via issue and occurs without PacketEvents or GrimAC present.

fabric/mc1201/src/main/java/io/github/retrooper/packetevents/mc1201/mixin/ConnectionMixin.java

@@ -29,6 +29,7 @@
 import com.github.retrooper.packetevents.util.PacketEventsImplHelper;
 import io.github.retrooper.packetevents.handler.PacketDecoder;
 import io.github.retrooper.packetevents.handler.PacketEncoder;
+import io.github.retrooper.packetevents.util.FabricInjectionUtil;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelPipeline;
@@ -43,48 +44,13 @@
 @Mixin(net.minecraft.network.Connection.class)
 public class ConnectionMixin {
 
-    // doesn't account for mods like ViaFabric
-    @Unique
-    private static final ClientVersion CLIENT_VERSION =
-            ClientVersion.getById(SharedConstants.getProtocolVersion());
-
     @Inject(
             method = "configureSerialization",
             at = @At("TAIL")
     )
     private static void configureSerialization(
             ChannelPipeline pipeline, PacketFlow flow, CallbackInfo ci
     ) {
-        PacketSide pipelineSide = switch (flow) {
-            case CLIENTBOUND -> PacketSide.CLIENT;
-            case SERVERBOUND -> PacketSide.SERVER;
-        };
-        PacketSide apiSide = PacketEvents.getAPI().getInjector().getPacketSide();
-        if (pipelineSide != apiSide) {
-            // if pipeline side doesn't match api side, don't inject into
-            // this pipeline - it probably means this is the pipeline from
-            // integrated server to minecraft client, which is currently unsupported
-            PacketEvents.getAPI().getLogManager().debug("Skipped pipeline injection on " + pipelineSide);
-            return;
-        }
-
-        PacketEvents.getAPI().getLogManager().debug("Game connected!");
-
-        Channel channel = pipeline.channel();
-        User user = new User(channel, ConnectionState.HANDSHAKING,
-                CLIENT_VERSION, new UserProfile(null, null));
-        ProtocolManager.USERS.put(channel.pipeline(), user);
-
-        UserConnectEvent connectEvent = new UserConnectEvent(user);
-        PacketEvents.getAPI().getEventManager().callEvent(connectEvent);
-        if (connectEvent.isCancelled()) {
-            channel.unsafe().closeForcibly();
-            return;
-        }
-
-        channel.pipeline().addBefore("decoder", PacketEvents.DECODER_NAME, new PacketDecoder(apiSide, user));
-        channel.pipeline().addBefore("encoder", PacketEvents.ENCODER_NAME, new PacketEncoder(apiSide, user));
-        channel.closeFuture().addListener((ChannelFutureListener) future ->
-                PacketEventsImplHelper.handleDisconnection(user.getChannel(), user.getUUID()));
+        FabricInjectionUtil.injectAtPipelineBuilder(pipeline, flow);
     }
 }

fabric/src/main/java/io/github/retrooper/packetevents/handler/PacketDecoder.java

@@ -26,6 +26,7 @@
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.MessageToMessageDecoder;
+import java.util.Arrays;
 import net.minecraft.world.entity.player.Player;
 import org.jetbrains.annotations.ApiStatus;
 
@@ -49,7 +50,7 @@ protected void decode(ChannelHandlerContext ctx, ByteBuf msg, List<Object> out)
             return;
         }
         PacketEventsImplHelper.handlePacket(ctx.channel(), this.user, this.player,
-                msg, false, this.side);
+                msg, true, this.side);
         if (msg.isReadable()) {
             out.add(msg.retain());
         }

fabric/src/main/java/io/github/retrooper/packetevents/handler/PacketEncoder.java

@@ -122,7 +122,7 @@ public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise)
     private @Nullable ProtocolPacketEvent handlePacket(ChannelHandlerContext ctx, ByteBuf buffer, ChannelPromise promise) throws Exception {
         // Process the packet using PacketEventsImplHelper (similar to Spigot)
         ProtocolPacketEvent protocolPacketEvent = PacketEventsImplHelper.handlePacket(
-            ctx.channel(), this.user, this.player, buffer, false, this.side
+            ctx.channel(), this.user, this.player, buffer, true, this.side
         );
 
         // Execute post-send tasks (required for cross-platform support)

fabric/src/main/java/io/github/retrooper/packetevents/util/FabricInjectionUtil.java

@@ -101,7 +101,6 @@ public static void reorderHandlers(ChannelHandlerContext ctx) {
             }
         }
 
-        // Log the pipeline for debugging
         PacketEvents.getAPI().getLogManager().debug("Pipeline after reorder: " + pipeline.names());
     }
 }