package net.minecraft.network.protocol.game;

import com.google.common.collect.Lists;
import io.netty.buffer.ByteBuf;
import java.util.BitSet;
import java.util.List;
import net.minecraft.core.SectionPos;
import net.minecraft.network.FriendlyByteBuf;
import net.minecraft.network.codec.ByteBufCodecs;
import net.minecraft.network.codec.StreamCodec;
import net.minecraft.world.level.ChunkPos;
import net.minecraft.world.level.LightLayer;
import net.minecraft.world.level.chunk.DataLayer;
import net.minecraft.world.level.lighting.LevelLightEngine;
import org.jspecify.annotations.Nullable;

public class ClientboundLightUpdatePacketData {
	private static final StreamCodec<ByteBuf, byte[]> DATA_LAYER_STREAM_CODEC = ByteBufCodecs.byteArray(2048);
	private final BitSet skyYMask;
	private final BitSet blockYMask;
	private final BitSet emptySkyYMask;
	private final BitSet emptyBlockYMask;
	private final List<byte[]> skyUpdates;
	private final List<byte[]> blockUpdates;

	public ClientboundLightUpdatePacketData(
		final ChunkPos chunkPos,
		final LevelLightEngine lightEngine,
		@Nullable final BitSet skyChangedLightSectionFilter,
		@Nullable final BitSet blockChangedLightSectionFilter
	) {
		this.skyYMask = new BitSet();
		this.blockYMask = new BitSet();
		this.emptySkyYMask = new BitSet();
		this.emptyBlockYMask = new BitSet();
		this.skyUpdates = Lists.<byte[]>newArrayList();
		this.blockUpdates = Lists.<byte[]>newArrayList();

		for (int sectionIndex = 0; sectionIndex < lightEngine.getLightSectionCount(); sectionIndex++) {
			if (skyChangedLightSectionFilter == null || skyChangedLightSectionFilter.get(sectionIndex)) {
				this.prepareSectionData(chunkPos, lightEngine, LightLayer.SKY, sectionIndex, this.skyYMask, this.emptySkyYMask, this.skyUpdates);
			}

			if (blockChangedLightSectionFilter == null || blockChangedLightSectionFilter.get(sectionIndex)) {
				this.prepareSectionData(chunkPos, lightEngine, LightLayer.BLOCK, sectionIndex, this.blockYMask, this.emptyBlockYMask, this.blockUpdates);
			}
		}
	}

	public ClientboundLightUpdatePacketData(final FriendlyByteBuf input, final int x, final int z) {
		this.skyYMask = input.readBitSet();
		this.blockYMask = input.readBitSet();
		this.emptySkyYMask = input.readBitSet();
		this.emptyBlockYMask = input.readBitSet();
		this.skyUpdates = input.readList(DATA_LAYER_STREAM_CODEC);
		this.blockUpdates = input.readList(DATA_LAYER_STREAM_CODEC);
	}

	public void write(final FriendlyByteBuf output) {
		output.writeBitSet(this.skyYMask);
		output.writeBitSet(this.blockYMask);
		output.writeBitSet(this.emptySkyYMask);
		output.writeBitSet(this.emptyBlockYMask);
		output.writeCollection(this.skyUpdates, DATA_LAYER_STREAM_CODEC);
		output.writeCollection(this.blockUpdates, DATA_LAYER_STREAM_CODEC);
	}

	private void prepareSectionData(
		final ChunkPos pos,
		final LevelLightEngine lightEngine,
		final LightLayer layer,
		final int sectionIndex,
		final BitSet mask,
		final BitSet emptyMask,
		final List<byte[]> updates
	) {
		DataLayer data = lightEngine.getLayerListener(layer).getDataLayerData(SectionPos.of(pos, lightEngine.getMinLightSection() + sectionIndex));
		if (data != null) {
			if (data.isEmpty()) {
				emptyMask.set(sectionIndex);
			} else {
				mask.set(sectionIndex);
				updates.add(data.copy().getData());
			}
		}
	}

	public BitSet getSkyYMask() {
		return this.skyYMask;
	}

	public BitSet getEmptySkyYMask() {
		return this.emptySkyYMask;
	}

	public List<byte[]> getSkyUpdates() {
		return this.skyUpdates;
	}

	public BitSet getBlockYMask() {
		return this.blockYMask;
	}

	public BitSet getEmptyBlockYMask() {
		return this.emptyBlockYMask;
	}

	public List<byte[]> getBlockUpdates() {
		return this.blockUpdates;
	}
}