minecraft-src/net/minecraft/world/level/block/piston/PistonHeadBlock.java

package net.minecraft.world.level.block.piston;

import com.mojang.serialization.MapCodec;
import java.util.Map;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.util.RandomSource;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.item.ItemStack;
import net.minecraft.world.level.BlockGetter;
import net.minecraft.world.level.Level;
import net.minecraft.world.level.LevelReader;
import net.minecraft.world.level.ScheduledTickAccess;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.block.Blocks;
import net.minecraft.world.level.block.DirectionalBlock;
import net.minecraft.world.level.block.Mirror;
import net.minecraft.world.level.block.Rotation;
import net.minecraft.world.level.block.state.BlockBehaviour;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.block.state.StateDefinition.Builder;
import net.minecraft.world.level.block.state.properties.BlockStateProperties;
import net.minecraft.world.level.block.state.properties.BooleanProperty;
import net.minecraft.world.level.block.state.properties.EnumProperty;
import net.minecraft.world.level.block.state.properties.PistonType;
import net.minecraft.world.level.pathfinder.PathComputationType;
import net.minecraft.world.level.redstone.ExperimentalRedstoneUtils;
import net.minecraft.world.level.redstone.Orientation;
import net.minecraft.world.phys.shapes.CollisionContext;
import net.minecraft.world.phys.shapes.Shapes;
import net.minecraft.world.phys.shapes.VoxelShape;
import org.jetbrains.annotations.Nullable;

public class PistonHeadBlock extends DirectionalBlock {
	public static final MapCodec<PistonHeadBlock> CODEC = simpleCodec(PistonHeadBlock::new);
	public static final EnumProperty<PistonType> TYPE = BlockStateProperties.PISTON_TYPE;
	public static final BooleanProperty SHORT = BlockStateProperties.SHORT;
	public static final int PLATFORM_THICKNESS = 4;
	private static final VoxelShape SHAPE_PLATFORM = Block.boxZ(16.0, 0.0, 4.0);
	private static final Map<Direction, VoxelShape> SHAPES_SHORT = Shapes.rotateAll(Shapes.or(SHAPE_PLATFORM, Block.boxZ(4.0, 4.0, 16.0)));
	private static final Map<Direction, VoxelShape> SHAPES = Shapes.rotateAll(Shapes.or(SHAPE_PLATFORM, Block.boxZ(4.0, 4.0, 20.0)));

	@Override
	protected MapCodec<PistonHeadBlock> codec() {
		return CODEC;
	}

	public PistonHeadBlock(BlockBehaviour.Properties properties) {
		super(properties);
		this.registerDefaultState(this.stateDefinition.any().setValue(FACING, Direction.NORTH).setValue(TYPE, PistonType.DEFAULT).setValue(SHORT, false));
	}

	@Override
	protected boolean useShapeForLightOcclusion(BlockState state) {
		return true;
	}

	@Override
	protected VoxelShape getShape(BlockState state, BlockGetter level, BlockPos pos, CollisionContext context) {
		return (VoxelShape)(state.getValue(SHORT) ? SHAPES_SHORT : SHAPES).get(state.getValue(FACING));
	}

	private boolean isFittingBase(BlockState baseState, BlockState extendedState) {
		Block block = baseState.getValue(TYPE) == PistonType.DEFAULT ? Blocks.PISTON : Blocks.STICKY_PISTON;
		return extendedState.is(block) && (Boolean)extendedState.getValue(PistonBaseBlock.EXTENDED) && extendedState.getValue(FACING) == baseState.getValue(FACING);
	}

	@Override
	public BlockState playerWillDestroy(Level level, BlockPos pos, BlockState state, Player player) {
		if (!level.isClientSide && player.preventsBlockDrops()) {
			BlockPos blockPos = pos.relative(((Direction)state.getValue(FACING)).getOpposite());
			if (this.isFittingBase(state, level.getBlockState(blockPos))) {
				level.destroyBlock(blockPos, false);
			}
		}

		return super.playerWillDestroy(level, pos, state, player);
	}

	@Override
	protected void affectNeighborsAfterRemoval(BlockState state, ServerLevel level, BlockPos pos, boolean movedByPiston) {
		BlockPos blockPos = pos.relative(((Direction)state.getValue(FACING)).getOpposite());
		if (this.isFittingBase(state, level.getBlockState(blockPos))) {
			level.destroyBlock(blockPos, true);
		}
	}

	@Override
	protected BlockState updateShape(
		BlockState state,
		LevelReader level,
		ScheduledTickAccess scheduledTickAccess,
		BlockPos pos,
		Direction direction,
		BlockPos neighborPos,
		BlockState neighborState,
		RandomSource random
	) {
		return direction.getOpposite() == state.getValue(FACING) && !state.canSurvive(level, pos)
			? Blocks.AIR.defaultBlockState()
			: super.updateShape(state, level, scheduledTickAccess, pos, direction, neighborPos, neighborState, random);
	}

	@Override
	protected boolean canSurvive(BlockState state, LevelReader level, BlockPos pos) {
		BlockState blockState = level.getBlockState(pos.relative(((Direction)state.getValue(FACING)).getOpposite()));
		return this.isFittingBase(state, blockState) || blockState.is(Blocks.MOVING_PISTON) && blockState.getValue(FACING) == state.getValue(FACING);
	}

	@Override
	protected void neighborChanged(BlockState state, Level level, BlockPos pos, Block neighborBlock, @Nullable Orientation orientation, boolean movedByPiston) {
		if (state.canSurvive(level, pos)) {
			level.neighborChanged(
				pos.relative(((Direction)state.getValue(FACING)).getOpposite()),
				neighborBlock,
				ExperimentalRedstoneUtils.withFront(orientation, ((Direction)state.getValue(FACING)).getOpposite())
			);
		}
	}

	@Override
	protected ItemStack getCloneItemStack(LevelReader level, BlockPos pos, BlockState state, boolean includeData) {
		return new ItemStack(state.getValue(TYPE) == PistonType.STICKY ? Blocks.STICKY_PISTON : Blocks.PISTON);
	}

	@Override
	protected BlockState rotate(BlockState state, Rotation rotation) {
		return state.setValue(FACING, rotation.rotate(state.getValue(FACING)));
	}

	@Override
	protected BlockState mirror(BlockState state, Mirror mirror) {
		return state.rotate(mirror.getRotation(state.getValue(FACING)));
	}

	@Override
	protected void createBlockStateDefinition(Builder<Block, BlockState> builder) {
		builder.add(FACING, TYPE, SHORT);
	}

	@Override
	protected boolean isPathfindable(BlockState state, PathComputationType pathComputationType) {
		return false;
	}
}