package net.minecraft.world.phys.shapes;

import net.minecraft.core.BlockPos;
import net.minecraft.world.entity.vehicle.minecart.AbstractMinecart;
import net.minecraft.world.level.CollisionGetter;
import net.minecraft.world.level.block.BaseRailBlock;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.block.state.properties.RailShape;
import org.jspecify.annotations.Nullable;

public class MinecartCollisionContext extends EntityCollisionContext {
	@Nullable
	private BlockPos ingoreBelow;
	@Nullable
	private BlockPos slopeIgnore;

	protected MinecartCollisionContext(final AbstractMinecart entity, final boolean alwaysStandOnFluid) {
		super(entity, alwaysStandOnFluid, false);
		this.setupContext(entity);
	}

	private void setupContext(final AbstractMinecart entity) {
		BlockPos currentRailPos = entity.getCurrentBlockPosOrRailBelow();
		BlockState currentState = entity.level().getBlockState(currentRailPos);
		boolean onRails = BaseRailBlock.isRail(currentState);
		if (onRails) {
			this.ingoreBelow = currentRailPos.below();
			RailShape shape = currentState.getValue(((BaseRailBlock)currentState.getBlock()).getShapeProperty());
			if (shape.isSlope()) {
				this.slopeIgnore = switch (shape) {
					case ASCENDING_EAST -> currentRailPos.east();
					case ASCENDING_WEST -> currentRailPos.west();
					case ASCENDING_NORTH -> currentRailPos.north();
					case ASCENDING_SOUTH -> currentRailPos.south();
					default -> null;
				};
			}
		}
	}

	@Override
	public VoxelShape getCollisionShape(final BlockState state, final CollisionGetter collisionGetter, final BlockPos pos) {
		return !pos.equals(this.ingoreBelow) && !pos.equals(this.slopeIgnore) ? super.getCollisionShape(state, collisionGetter, pos) : Shapes.empty();
	}
}