package net.minecraft.network;

import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.DecoderException;
import io.netty.handler.codec.MessageToMessageDecoder;
import java.util.List;
import net.minecraft.network.protocol.BundlerInfo;
import net.minecraft.network.protocol.Packet;
import org.jspecify.annotations.Nullable;

public class PacketBundlePacker extends MessageToMessageDecoder<Packet<?>> {
	private final BundlerInfo bundlerInfo;
	@Nullable
	private BundlerInfo.Bundler currentBundler;

	public PacketBundlePacker(final BundlerInfo bundlerInfo) {
		this.bundlerInfo = bundlerInfo;
	}

	protected void decode(final ChannelHandlerContext ctx, final Packet<?> msg, final List<Object> out) throws Exception {
		if (this.currentBundler != null) {
			verifyNonTerminalPacket(msg);
			Packet<?> bundlePacket = this.currentBundler.addPacket(msg);
			if (bundlePacket != null) {
				this.currentBundler = null;
				out.add(bundlePacket);
			}
		} else {
			BundlerInfo.Bundler bundler = this.bundlerInfo.startPacketBundling(msg);
			if (bundler != null) {
				verifyNonTerminalPacket(msg);
				this.currentBundler = bundler;
			} else {
				out.add(msg);
				if (msg.isTerminal()) {
					ctx.pipeline().remove(ctx.name());
				}
			}
		}
	}

	private static void verifyNonTerminalPacket(final Packet<?> msg) {
		if (msg.isTerminal()) {
			throw new DecoderException("Terminal message received in bundle");
		}
	}
}