package net.minecraft.server.level;

import net.minecraft.world.level.ChunkPos;
import net.minecraft.world.level.lighting.DynamicGraphMinFixedPoint;

public abstract class ChunkTracker extends DynamicGraphMinFixedPoint {
	protected ChunkTracker(final int levelCount, final int minQueueSize, final int minMapSize) {
		super(levelCount, minQueueSize, minMapSize);
	}

	@Override
	protected boolean isSource(final long node) {
		return node == ChunkPos.INVALID_CHUNK_POS;
	}

	@Override
	protected void checkNeighborsAfterUpdate(final long node, final int level, final boolean onlyDecrease) {
		if (!onlyDecrease || level < this.levelCount - 2) {
			ChunkPos pos = ChunkPos.unpack(node);
			int x = pos.x();
			int z = pos.z();

			for (int offsetX = -1; offsetX <= 1; offsetX++) {
				for (int offsetZ = -1; offsetZ <= 1; offsetZ++) {
					long neighbor = ChunkPos.pack(x + offsetX, z + offsetZ);
					if (neighbor != node) {
						this.checkNeighbor(node, neighbor, level, onlyDecrease);
					}
				}
			}
		}
	}

	@Override
	protected int getComputedLevel(final long node, final long knownParent, final int knownLevelFromParent) {
		int computedLevel = knownLevelFromParent;
		ChunkPos pos = ChunkPos.unpack(node);
		int x = pos.x();
		int z = pos.z();

		for (int offsetX = -1; offsetX <= 1; offsetX++) {
			for (int offsetZ = -1; offsetZ <= 1; offsetZ++) {
				long neighbor = ChunkPos.pack(x + offsetX, z + offsetZ);
				if (neighbor == node) {
					neighbor = ChunkPos.INVALID_CHUNK_POS;
				}

				if (neighbor != knownParent) {
					int costFromNeighbor = this.computeLevelFromNeighbor(neighbor, node, this.getLevel(neighbor));
					if (computedLevel > costFromNeighbor) {
						computedLevel = costFromNeighbor;
					}

					if (computedLevel == 0) {
						return computedLevel;
					}
				}
			}
		}

		return computedLevel;
	}

	@Override
	protected int computeLevelFromNeighbor(final long from, final long to, final int fromLevel) {
		return from == ChunkPos.INVALID_CHUNK_POS ? this.getLevelFromSource(to) : fromLevel + 1;
	}

	protected abstract int getLevelFromSource(long to);

	public void update(final long node, final int newLevelFrom, final boolean onlyDecreased) {
		this.checkEdge(ChunkPos.INVALID_CHUNK_POS, node, newLevelFrom, onlyDecreased);
	}
}