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.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.jetbrains.annotations.Nullable;

public class DismountHelper {
	public static int[][] offsetsForDirection(Direction direction) {
		Direction direction2 = direction.getClockWise();
		Direction direction3 = direction2.getOpposite();
		Direction direction4 = direction.getOpposite();
		return new int[][]{
			{direction2.getStepX(), direction2.getStepZ()},
			{direction3.getStepX(), direction3.getStepZ()},
			{direction4.getStepX() + direction2.getStepX(), direction4.getStepZ() + direction2.getStepZ()},
			{direction4.getStepX() + direction3.getStepX(), direction4.getStepZ() + direction3.getStepZ()},
			{direction.getStepX() + direction2.getStepX(), direction.getStepZ() + direction2.getStepZ()},
			{direction.getStepX() + direction3.getStepX(), direction.getStepZ() + direction3.getStepZ()},
			{direction4.getStepX(), direction4.getStepZ()},
			{direction.getStepX(), direction.getStepZ()}
		};
	}

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

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

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

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

	public static VoxelShape nonClimbableShape(BlockGetter level, 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(BlockPos pos, int ceiling, Function<BlockPos, VoxelShape> shapeForPos) {
		BlockPos.MutableBlockPos mutableBlockPos = pos.mutable();
		int i = 0;

		while (i < ceiling) {
			VoxelShape voxelShape = (VoxelShape)shapeForPos.apply(mutableBlockPos);
			if (!voxelShape.isEmpty()) {
				return pos.getY() + i + voxelShape.min(Direction.Axis.Y);
			}

			i++;
			mutableBlockPos.move(Direction.UP);
		}

		return Double.POSITIVE_INFINITY;
	}

	@Nullable
	public static Vec3 findSafeDismountLocation(EntityType<?> entityType, CollisionGetter level, BlockPos pos, boolean onlySafePositions) {
		if (onlySafePositions && entityType.isBlockDangerous(level.getBlockState(pos))) {
			return null;
		} else {
			double d = level.getBlockFloorHeight(nonClimbableShape(level, pos), () -> nonClimbableShape(level, pos.below()));
			if (!isBlockFloorValid(d)) {
				return null;
			} else if (onlySafePositions && d <= 0.0 && entityType.isBlockDangerous(level.getBlockState(pos.below()))) {
				return null;
			} else {
				Vec3 vec3 = Vec3.upFromBottomCenterOf(pos, d);
				AABB aABB = entityType.getDimensions().makeBoundingBox(vec3);

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

				if (entityType != EntityType.PLAYER
					|| !level.getBlockState(pos).is(BlockTags.INVALID_SPAWN_INSIDE) && !level.getBlockState(pos.above()).is(BlockTags.INVALID_SPAWN_INSIDE)) {
					return !level.getWorldBorder().isWithinBounds(aABB) ? null : vec3;
				} else {
					return null;
				}
			}
		}
	}
}