package net.minecraft.network.protocol.game;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import java.util.List;
import net.minecraft.network.FriendlyByteBuf;
import net.minecraft.network.codec.StreamCodec;
import net.minecraft.network.protocol.Packet;
import net.minecraft.network.protocol.PacketType;
import net.minecraft.world.level.ChunkPos;
import net.minecraft.world.level.chunk.LevelChunk;
import net.minecraft.world.level.chunk.LevelChunkSection;

public record ClientboundChunksBiomesPacket(List<ClientboundChunksBiomesPacket.ChunkBiomeData> chunkBiomeData) implements Packet<ClientGamePacketListener> {
	public static final StreamCodec<FriendlyByteBuf, ClientboundChunksBiomesPacket> STREAM_CODEC = Packet.codec(
		ClientboundChunksBiomesPacket::write, ClientboundChunksBiomesPacket::new
	);
	private static final int TWO_MEGABYTES = 2097152;

	private ClientboundChunksBiomesPacket(final FriendlyByteBuf input) {
		this(input.readList(ClientboundChunksBiomesPacket.ChunkBiomeData::new));
	}

	public static ClientboundChunksBiomesPacket forChunks(final List<LevelChunk> chunks) {
		return new ClientboundChunksBiomesPacket(chunks.stream().map(ClientboundChunksBiomesPacket.ChunkBiomeData::new).toList());
	}

	private void write(final FriendlyByteBuf output) {
		output.writeCollection(this.chunkBiomeData, (o, c) -> c.write(o));
	}

	@Override
	public PacketType<ClientboundChunksBiomesPacket> type() {
		return GamePacketTypes.CLIENTBOUND_CHUNKS_BIOMES;
	}

	public void handle(final ClientGamePacketListener listener) {
		listener.handleChunksBiomes(this);
	}

	public record ChunkBiomeData(ChunkPos pos, byte[] buffer) {
		public ChunkBiomeData(final LevelChunk chunk) {
			this(chunk.getPos(), new byte[calculateChunkSize(chunk)]);
			extractChunkData(new FriendlyByteBuf(this.getWriteBuffer()), chunk);
		}

		public ChunkBiomeData(final FriendlyByteBuf input) {
			this(input.readChunkPos(), input.readByteArray(2097152));
		}

		private static int calculateChunkSize(final LevelChunk chunk) {
			int total = 0;

			for (LevelChunkSection section : chunk.getSections()) {
				total += section.getBiomes().getSerializedSize();
			}

			return total;
		}

		public FriendlyByteBuf getReadBuffer() {
			return new FriendlyByteBuf(Unpooled.wrappedBuffer(this.buffer));
		}

		private ByteBuf getWriteBuffer() {
			ByteBuf buffer = Unpooled.wrappedBuffer(this.buffer);
			buffer.writerIndex(0);
			return buffer;
		}

		public static void extractChunkData(final FriendlyByteBuf buffer, final LevelChunk chunk) {
			for (LevelChunkSection section : chunk.getSections()) {
				section.getBiomes().write(buffer);
			}

			if (buffer.writerIndex() != buffer.capacity()) {
				throw new IllegalStateException("Didn't fill biome buffer: expected " + buffer.capacity() + " bytes, got " + buffer.writerIndex());
			}
		}

		public void write(final FriendlyByteBuf output) {
			output.writeChunkPos(this.pos);
			output.writeByteArray(this.buffer);
		}
	}
}