package net.minecraft.world.level.lighting;

import it.unimi.dsi.fastutil.longs.LongArrayFIFOQueue;
import it.unimi.dsi.fastutil.longs.LongIterator;
import it.unimi.dsi.fastutil.longs.LongOpenHashSet;
import java.util.Arrays;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.core.SectionPos;
import net.minecraft.world.level.ChunkPos;
import net.minecraft.world.level.block.Blocks;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.chunk.DataLayer;
import net.minecraft.world.level.chunk.LightChunk;
import net.minecraft.world.level.chunk.LightChunkGetter;
import net.minecraft.world.phys.shapes.Shapes;
import net.minecraft.world.phys.shapes.VoxelShape;
import org.jetbrains.annotations.Nullable;

public abstract class LightEngine<M extends DataLayerStorageMap<M>, S extends LayerLightSectionStorage<M>> implements LayerLightEventListener {
	public static final int MAX_LEVEL = 15;
	protected static final int MIN_OPACITY = 1;
	protected static final long PULL_LIGHT_IN_ENTRY = LightEngine.QueueEntry.decreaseAllDirections(1);
	private static final int MIN_QUEUE_SIZE = 512;
	protected static final Direction[] PROPAGATION_DIRECTIONS = Direction.values();
	protected final LightChunkGetter chunkSource;
	protected final S storage;
	private final LongOpenHashSet blockNodesToCheck = new LongOpenHashSet(512, 0.5F);
	private final LongArrayFIFOQueue decreaseQueue = new LongArrayFIFOQueue();
	private final LongArrayFIFOQueue increaseQueue = new LongArrayFIFOQueue();
	private static final int CACHE_SIZE = 2;
	private final long[] lastChunkPos = new long[2];
	private final LightChunk[] lastChunk = new LightChunk[2];

	protected LightEngine(LightChunkGetter chunkSource, S storage) {
		this.chunkSource = chunkSource;
		this.storage = storage;
		this.clearChunkCache();
	}

	public static boolean hasDifferentLightProperties(BlockState state1, BlockState state2) {
		return state2 == state1
			? false
			: state2.getLightBlock() != state1.getLightBlock()
				|| state2.getLightEmission() != state1.getLightEmission()
				|| state2.useShapeForLightOcclusion()
				|| state1.useShapeForLightOcclusion();
	}

	public static int getLightBlockInto(BlockState state1, BlockState state2, Direction direction, int defaultReturnValue) {
		boolean bl = isEmptyShape(state1);
		boolean bl2 = isEmptyShape(state2);
		if (bl && bl2) {
			return defaultReturnValue;
		} else {
			VoxelShape voxelShape = bl ? Shapes.empty() : state1.getOcclusionShape();
			VoxelShape voxelShape2 = bl2 ? Shapes.empty() : state2.getOcclusionShape();
			return Shapes.mergedFaceOccludes(voxelShape, voxelShape2, direction) ? 16 : defaultReturnValue;
		}
	}

	public static VoxelShape getOcclusionShape(BlockState state, Direction direction) {
		return isEmptyShape(state) ? Shapes.empty() : state.getFaceOcclusionShape(direction);
	}

	protected static boolean isEmptyShape(BlockState state) {
		return !state.canOcclude() || !state.useShapeForLightOcclusion();
	}

	protected BlockState getState(BlockPos pos) {
		int i = SectionPos.blockToSectionCoord(pos.getX());
		int j = SectionPos.blockToSectionCoord(pos.getZ());
		LightChunk lightChunk = this.getChunk(i, j);
		return lightChunk == null ? Blocks.BEDROCK.defaultBlockState() : lightChunk.getBlockState(pos);
	}

	protected int getOpacity(BlockState state) {
		return Math.max(1, state.getLightBlock());
	}

	protected boolean shapeOccludes(BlockState state1, BlockState state2, Direction direction) {
		VoxelShape voxelShape = getOcclusionShape(state1, direction);
		VoxelShape voxelShape2 = getOcclusionShape(state2, direction.getOpposite());
		return Shapes.faceShapeOccludes(voxelShape, voxelShape2);
	}

	@Nullable
	protected LightChunk getChunk(int x, int z) {
		long l = ChunkPos.asLong(x, z);

		for (int i = 0; i < 2; i++) {
			if (l == this.lastChunkPos[i]) {
				return this.lastChunk[i];
			}
		}

		LightChunk lightChunk = this.chunkSource.getChunkForLighting(x, z);

		for (int j = 1; j > 0; j--) {
			this.lastChunkPos[j] = this.lastChunkPos[j - 1];
			this.lastChunk[j] = this.lastChunk[j - 1];
		}

		this.lastChunkPos[0] = l;
		this.lastChunk[0] = lightChunk;
		return lightChunk;
	}

	private void clearChunkCache() {
		Arrays.fill(this.lastChunkPos, ChunkPos.INVALID_CHUNK_POS);
		Arrays.fill(this.lastChunk, null);
	}

	@Override
	public void checkBlock(BlockPos pos) {
		this.blockNodesToCheck.add(pos.asLong());
	}

	public void queueSectionData(long sectionPos, @Nullable DataLayer data) {
		this.storage.queueSectionData(sectionPos, data);
	}

	public void retainData(ChunkPos chunkPos, boolean retainData) {
		this.storage.retainData(SectionPos.getZeroNode(chunkPos.x, chunkPos.z), retainData);
	}

	@Override
	public void updateSectionStatus(SectionPos pos, boolean isQueueEmpty) {
		this.storage.updateSectionStatus(pos.asLong(), isQueueEmpty);
	}

	@Override
	public void setLightEnabled(ChunkPos chunkPos, boolean lightEnabled) {
		this.storage.setLightEnabled(SectionPos.getZeroNode(chunkPos.x, chunkPos.z), lightEnabled);
	}

	@Override
	public int runLightUpdates() {
		LongIterator longIterator = this.blockNodesToCheck.iterator();

		while (longIterator.hasNext()) {
			this.checkNode(longIterator.nextLong());
		}

		this.blockNodesToCheck.clear();
		this.blockNodesToCheck.trim(512);
		int i = 0;
		i += this.propagateDecreases();
		i += this.propagateIncreases();
		this.clearChunkCache();
		this.storage.markNewInconsistencies(this);
		this.storage.swapSectionMap();
		return i;
	}

	private int propagateIncreases() {
		int i;
		for (i = 0; !this.increaseQueue.isEmpty(); i++) {
			long l = this.increaseQueue.dequeueLong();
			long m = this.increaseQueue.dequeueLong();
			int j = this.storage.getStoredLevel(l);
			int k = LightEngine.QueueEntry.getFromLevel(m);
			if (LightEngine.QueueEntry.isIncreaseFromEmission(m) && j < k) {
				this.storage.setStoredLevel(l, k);
				j = k;
			}

			if (j == k) {
				this.propagateIncrease(l, m, j);
			}
		}

		return i;
	}

	private int propagateDecreases() {
		int i;
		for (i = 0; !this.decreaseQueue.isEmpty(); i++) {
			long l = this.decreaseQueue.dequeueLong();
			long m = this.decreaseQueue.dequeueLong();
			this.propagateDecrease(l, m);
		}

		return i;
	}

	protected void enqueueDecrease(long packedPos1, long packedPos2) {
		this.decreaseQueue.enqueue(packedPos1);
		this.decreaseQueue.enqueue(packedPos2);
	}

	protected void enqueueIncrease(long packedPos1, long packedPos2) {
		this.increaseQueue.enqueue(packedPos1);
		this.increaseQueue.enqueue(packedPos2);
	}

	@Override
	public boolean hasLightWork() {
		return this.storage.hasInconsistencies() || !this.blockNodesToCheck.isEmpty() || !this.decreaseQueue.isEmpty() || !this.increaseQueue.isEmpty();
	}

	@Nullable
	@Override
	public DataLayer getDataLayerData(SectionPos sectionPos) {
		return this.storage.getDataLayerData(sectionPos.asLong());
	}

	@Override
	public int getLightValue(BlockPos levelPos) {
		return this.storage.getLightValue(levelPos.asLong());
	}

	public String getDebugData(long sectionPos) {
		return this.getDebugSectionType(sectionPos).display();
	}

	public LayerLightSectionStorage.SectionType getDebugSectionType(long sectionPos) {
		return this.storage.getDebugSectionType(sectionPos);
	}

	protected abstract void checkNode(long packedPos);

	protected abstract void propagateIncrease(long packedPos, long queueEntry, int lightLevel);

	protected abstract void propagateDecrease(long packedPos, long lightLevel);

	public static class QueueEntry {
		private static final int FROM_LEVEL_BITS = 4;
		private static final int DIRECTION_BITS = 6;
		private static final long LEVEL_MASK = 15L;
		private static final long DIRECTIONS_MASK = 1008L;
		private static final long FLAG_FROM_EMPTY_SHAPE = 1024L;
		private static final long FLAG_INCREASE_FROM_EMISSION = 2048L;

		public static long decreaseSkipOneDirection(int level, Direction direction) {
			long l = withoutDirection(1008L, direction);
			return withLevel(l, level);
		}

		public static long decreaseAllDirections(int level) {
			return withLevel(1008L, level);
		}

		public static long increaseLightFromEmission(int level, boolean fromEmptyShape) {
			long l = 1008L;
			l |= 2048L;
			if (fromEmptyShape) {
				l |= 1024L;
			}

			return withLevel(l, level);
		}

		public static long increaseSkipOneDirection(int level, boolean fromEmptyShape, Direction direction) {
			long l = withoutDirection(1008L, direction);
			if (fromEmptyShape) {
				l |= 1024L;
			}

			return withLevel(l, level);
		}

		public static long increaseOnlyOneDirection(int level, boolean fromEmptyShape, Direction direction) {
			long l = 0L;
			if (fromEmptyShape) {
				l |= 1024L;
			}

			l = withDirection(l, direction);
			return withLevel(l, level);
		}

		public static long increaseSkySourceInDirections(boolean down, boolean north, boolean south, boolean west, boolean east) {
			long l = withLevel(0L, 15);
			if (down) {
				l = withDirection(l, Direction.DOWN);
			}

			if (north) {
				l = withDirection(l, Direction.NORTH);
			}

			if (south) {
				l = withDirection(l, Direction.SOUTH);
			}

			if (west) {
				l = withDirection(l, Direction.WEST);
			}

			if (east) {
				l = withDirection(l, Direction.EAST);
			}

			return l;
		}

		public static int getFromLevel(long entry) {
			return (int)(entry & 15L);
		}

		public static boolean isFromEmptyShape(long entry) {
			return (entry & 1024L) != 0L;
		}

		public static boolean isIncreaseFromEmission(long entry) {
			return (entry & 2048L) != 0L;
		}

		public static boolean shouldPropagateInDirection(long entry, Direction direction) {
			return (entry & 1L << direction.ordinal() + 4) != 0L;
		}

		private static long withLevel(long entry, int level) {
			return entry & -16L | level & 15L;
		}

		private static long withDirection(long entry, Direction direction) {
			return entry | 1L << direction.ordinal() + 4;
		}

		private static long withoutDirection(long entry, Direction direction) {
			return entry & ~(1L << direction.ordinal() + 4);
		}
	}
}