package net.minecraft.world.entity.vehicle;

import java.util.function.Function;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.tags.BlockTags;
import net.minecraft.world.entity.EntityType;
import net.minecraft.world.entity.EntityTypes;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.entity.Pose;
import net.minecraft.world.level.BlockGetter;
import net.minecraft.world.level.CollisionGetter;
import net.minecraft.world.level.block.TrapDoorBlock;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.phys.AABB;
import net.minecraft.world.phys.Vec3;
import net.minecraft.world.phys.shapes.Shapes;
import net.minecraft.world.phys.shapes.VoxelShape;
import org.jspecify.annotations.Nullable;

public class DismountHelper {
	public static int[][] offsetsForDirection(final Direction forward) {
		Direction right = forward.getClockWise();
		Direction left = right.getOpposite();
		Direction back = forward.getOpposite();
		return new int[][]{
			{right.getStepX(), right.getStepZ()},
			{left.getStepX(), left.getStepZ()},
			{back.getStepX() + right.getStepX(), back.getStepZ() + right.getStepZ()},
			{back.getStepX() + left.getStepX(), back.getStepZ() + left.getStepZ()},
			{forward.getStepX() + right.getStepX(), forward.getStepZ() + right.getStepZ()},
			{forward.getStepX() + left.getStepX(), forward.getStepZ() + left.getStepZ()},
			{back.getStepX(), back.getStepZ()},
			{forward.getStepX(), forward.getStepZ()}
		};
	}

	public static boolean isBlockFloorValid(final double blockFloorHeight) {
		return !Double.isInfinite(blockFloorHeight) && blockFloorHeight < 1.0;
	}

	public static boolean canDismountTo(final CollisionGetter level, final LivingEntity passenger, final AABB box) {
		for (VoxelShape collision : level.getBlockCollisions(passenger, box)) {
			if (!collision.isEmpty()) {
				return false;
			}
		}

		return level.getWorldBorder().isWithinBounds(box);
	}

	public static boolean canDismountTo(final CollisionGetter level, final Vec3 location, final LivingEntity passenger, final Pose dismountPose) {
		return canDismountTo(level, passenger, passenger.getLocalBoundsForPose(dismountPose).move(location));
	}

	public static VoxelShape nonClimbableShape(final BlockGetter level, final BlockPos pos) {
		BlockState blockState = level.getBlockState(pos);
		return !blockState.is(BlockTags.CLIMBABLE) && (!(blockState.getBlock() instanceof TrapDoorBlock) || !blockState.getValue(TrapDoorBlock.OPEN))
			? blockState.getCollisionShape(level, pos)
			: Shapes.empty();
	}

	public static double findCeilingFrom(final BlockPos pos, final int blocks, final Function<BlockPos, VoxelShape> shapeGetter) {
		BlockPos.MutableBlockPos cursor = pos.mutable();
		int y = 0;

		while (y < blocks) {
			VoxelShape collisionShape = (VoxelShape)shapeGetter.apply(cursor);
			if (!collisionShape.isEmpty()) {
				return pos.getY() + y + collisionShape.min(Direction.Axis.Y);
			}

			y++;
			cursor.move(Direction.UP);
		}

		return Double.POSITIVE_INFINITY;
	}

	@Nullable
	public static Vec3 findSafeDismountLocation(final EntityType<?> type, final CollisionGetter level, final BlockPos blockPos, final boolean checkDangerous) {
		if (checkDangerous && type.isBlockDangerous(level.getBlockState(blockPos))) {
			return null;
		} else {
			double floorHeight = level.getBlockFloorHeight(nonClimbableShape(level, blockPos), () -> nonClimbableShape(level, blockPos.below()));
			if (!isBlockFloorValid(floorHeight)) {
				return null;
			} else if (checkDangerous && floorHeight <= 0.0 && type.isBlockDangerous(level.getBlockState(blockPos.below()))) {
				return null;
			} else {
				Vec3 position = Vec3.upFromBottomCenterOf(blockPos, floorHeight);
				AABB aabb = type.getDimensions().makeBoundingBox(position);

				for (VoxelShape shape : level.getBlockCollisions(null, aabb)) {
					if (!shape.isEmpty()) {
						return null;
					}
				}

				if (type != EntityTypes.PLAYER
					|| !level.getBlockState(blockPos).is(BlockTags.INVALID_SPAWN_INSIDE) && !level.getBlockState(blockPos.above()).is(BlockTags.INVALID_SPAWN_INSIDE)) {
					return !level.getWorldBorder().isWithinBounds(aabb) ? null : position;
				} else {
					return null;
				}
			}
		}
	}
}