package net.minecraft.world.level.block;

import java.util.Optional;
import java.util.OptionalInt;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.util.Mth;
import net.minecraft.world.phys.BlockHitResult;
import net.minecraft.world.phys.Vec2;
import net.minecraft.world.phys.Vec3;

public interface SelectableSlotContainer {
	int getRows();

	int getColumns();

	default OptionalInt getHitSlot(final BlockHitResult hitResult, final Direction blockFacing) {
		return (OptionalInt)getRelativeHitCoordinatesForBlockFace(hitResult, blockFacing).map(hitCoords -> {
			int row = getSection(1.0F - hitCoords.y, this.getRows());
			int column = getSection(hitCoords.x, this.getColumns());
			return OptionalInt.of(column + row * this.getColumns());
		}).orElseGet(OptionalInt::empty);
	}

	private static Optional<Vec2> getRelativeHitCoordinatesForBlockFace(final BlockHitResult hitResult, final Direction blockFacing) {
		Direction hitDirection = hitResult.getDirection();
		if (blockFacing != hitDirection) {
			return Optional.empty();
		} else {
			BlockPos hitBlockPos = hitResult.getBlockPos().relative(hitDirection);
			Vec3 relativeHit = hitResult.getLocation().subtract(hitBlockPos.getX(), hitBlockPos.getY(), hitBlockPos.getZ());
			double relativeX = relativeHit.x();
			double relativeY = relativeHit.y();
			double relativeZ = relativeHit.z();

			return switch (hitDirection) {
				case NORTH -> Optional.of(new Vec2((float)(1.0 - relativeX), (float)relativeY));
				case SOUTH -> Optional.of(new Vec2((float)relativeX, (float)relativeY));
				case WEST -> Optional.of(new Vec2((float)relativeZ, (float)relativeY));
				case EAST -> Optional.of(new Vec2((float)(1.0 - relativeZ), (float)relativeY));
				case DOWN, UP -> Optional.empty();
			};
		}
	}

	private static int getSection(final float relativeCoordinate, final int maxSections) {
		float targetedPixel = relativeCoordinate * 16.0F;
		float sectionSize = 16.0F / maxSections;
		return Mth.clamp(Mth.floor(targetedPixel / sectionSize), 0, maxSections - 1);
	}
}