package net.minecraft.util;

import net.minecraft.core.BlockPos;
import net.minecraft.world.level.BlockAndLightGetter;
import net.minecraft.world.level.LightLayer;
import net.minecraft.world.level.block.state.BlockState;

public class LightCoordsUtil {
	public static final int FULL_BRIGHT = 15728880;
	public static final int FULL_SKY = 15728640;
	private static final int MAX_SMOOTH_LIGHT_LEVEL = 240;

	public static int pack(final int block, final int sky) {
		return block << 4 | sky << 20;
	}

	public static int block(final int packed) {
		return packed >> 4 & 15;
	}

	public static int sky(final int packed) {
		return packed >> 20 & 15;
	}

	public static int withBlock(final int coords, final int block) {
		return coords & 0xFF0000 | block << 4;
	}

	public static int smoothPack(final int block, final int sky) {
		return block & 0xFF | (sky & 0xFF) << 16;
	}

	public static int smoothBlock(final int packed) {
		return packed & 0xFF;
	}

	public static int smoothSky(final int packed) {
		return packed >> 16 & 0xFF;
	}

	public static int addSmoothBlockEmission(final int lightCoords, float blockLightEmission) {
		blockLightEmission = Mth.clamp(blockLightEmission, 0.0F, 1.0F);
		int emittedBlock = (int)(Mth.clamp(blockLightEmission, 0.0F, 1.0F) * 240.0F);
		int block = Math.min(smoothBlock(lightCoords) + emittedBlock, 240);
		return smoothPack(block, smoothSky(lightCoords));
	}

	public static int max(final int coords1, final int coords2) {
		int block1 = block(coords1);
		int block2 = block(coords2);
		int sky1 = sky(coords1);
		int sky2 = sky(coords2);
		return pack(Math.max(block1, block2), Math.max(sky1, sky2));
	}

	public static int lightCoordsWithEmission(final int lightCoords, final int emission) {
		if (emission == 0) {
			return lightCoords;
		} else {
			int sky = Math.max(sky(lightCoords), emission);
			int block = Math.max(block(lightCoords), emission);
			return pack(block, sky);
		}
	}

	public static int smoothBlend(int neighbor1, int neighbor2, int neighbor3, final int center) {
		if (sky(center) > 2 || block(center) > 2) {
			if (neighbor1 == 0) {
				neighbor1 = center;
			} else if (sky(neighbor1) == 0) {
				neighbor1 |= center & 0xFF0000;
			}

			if (neighbor2 == 0) {
				neighbor2 = center;
			} else if (sky(neighbor2) == 0) {
				neighbor2 |= center & 0xFF0000;
			}

			if (neighbor3 == 0) {
				neighbor3 = center;
			} else if (sky(neighbor3) == 0) {
				neighbor3 |= center & 0xFF0000;
			}
		}

		return neighbor1 + neighbor2 + neighbor3 + center >> 2 & 16711935;
	}

	public static int smoothWeightedBlend(
		final int coords1,
		final int coords2,
		final int coords3,
		final int coords4,
		final float weight1,
		final float weight2,
		final float weight3,
		final float weight4
	) {
		int sky = (int)(smoothSky(coords1) * weight1 + smoothSky(coords2) * weight2 + smoothSky(coords3) * weight3 + smoothSky(coords4) * weight4);
		int block = (int)(smoothBlock(coords1) * weight1 + smoothBlock(coords2) * weight2 + smoothBlock(coords3) * weight3 + smoothBlock(coords4) * weight4);
		return smoothPack(block, sky);
	}

	public static int getLightCoords(final BlockAndLightGetter level, final BlockPos pos) {
		return getLightCoords(LightCoordsUtil.BrightnessGetter.DEFAULT, level, level.getBlockState(pos), pos);
	}

	public static int getLightCoords(
		final LightCoordsUtil.BrightnessGetter brightnessGetter, final BlockAndLightGetter level, final BlockState state, final BlockPos pos
	) {
		if (state.emissiveRendering()) {
			return 15728880;
		} else {
			int packedBrightness = brightnessGetter.packedBrightness(level, pos);
			int block = block(packedBrightness);
			int blockSelfEmission = state.getLightEmission();
			return block < blockSelfEmission ? withBlock(packedBrightness, blockSelfEmission) : packedBrightness;
		}
	}

	@FunctionalInterface
	public interface BrightnessGetter {
		LightCoordsUtil.BrightnessGetter DEFAULT = (level, pos) -> {
			int sky = level.getBrightness(LightLayer.SKY, pos);
			int block = level.getBrightness(LightLayer.BLOCK, pos);
			return LightCoordsUtil.pack(block, sky);
		};

		int packedBrightness(BlockAndLightGetter level, BlockPos pos);
	}
}