minecraft-src/net/minecraft/world/level/block/MultifaceSpreader.java

package net.minecraft.world.level.block;

import com.google.common.annotations.VisibleForTesting;
import java.util.Optional;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.util.RandomSource;
import net.minecraft.world.level.BlockGetter;
import net.minecraft.world.level.LevelAccessor;
import net.minecraft.world.level.block.state.BlockState;
import org.jetbrains.annotations.Nullable;

public class MultifaceSpreader {
	public static final MultifaceSpreader.SpreadType[] DEFAULT_SPREAD_ORDER = new MultifaceSpreader.SpreadType[]{
		MultifaceSpreader.SpreadType.SAME_POSITION, MultifaceSpreader.SpreadType.SAME_PLANE, MultifaceSpreader.SpreadType.WRAP_AROUND
	};
	private final MultifaceSpreader.SpreadConfig config;

	public MultifaceSpreader(MultifaceBlock block) {
		this(new MultifaceSpreader.DefaultSpreaderConfig(block));
	}

	public MultifaceSpreader(MultifaceSpreader.SpreadConfig config) {
		this.config = config;
	}

	public boolean canSpreadInAnyDirection(BlockState state, BlockGetter level, BlockPos pos, Direction spreadDirection) {
		return Direction.stream()
			.anyMatch(direction2 -> this.getSpreadFromFaceTowardDirection(state, level, pos, spreadDirection, direction2, this.config::canSpreadInto).isPresent());
	}

	public Optional<MultifaceSpreader.SpreadPos> spreadFromRandomFaceTowardRandomDirection(
		BlockState state, LevelAccessor level, BlockPos pos, RandomSource random
	) {
		return (Optional<MultifaceSpreader.SpreadPos>)Direction.allShuffled(random)
			.stream()
			.filter(direction -> this.config.canSpreadFrom(state, direction))
			.map(direction -> this.spreadFromFaceTowardRandomDirection(state, level, pos, direction, random, false))
			.filter(Optional::isPresent)
			.findFirst()
			.orElse(Optional.empty());
	}

	public long spreadAll(BlockState state, LevelAccessor level, BlockPos pos, boolean markForPostprocessing) {
		return (Long)Direction.stream()
			.filter(direction -> this.config.canSpreadFrom(state, direction))
			.map(direction -> this.spreadFromFaceTowardAllDirections(state, level, pos, direction, markForPostprocessing))
			.reduce(0L, Long::sum);
	}

	public Optional<MultifaceSpreader.SpreadPos> spreadFromFaceTowardRandomDirection(
		BlockState state, LevelAccessor level, BlockPos pos, Direction spreadDirection, RandomSource random, boolean markForPostprocessing
	) {
		return (Optional<MultifaceSpreader.SpreadPos>)Direction.allShuffled(random)
			.stream()
			.map(direction2 -> this.spreadFromFaceTowardDirection(state, level, pos, spreadDirection, direction2, markForPostprocessing))
			.filter(Optional::isPresent)
			.findFirst()
			.orElse(Optional.empty());
	}

	private long spreadFromFaceTowardAllDirections(BlockState state, LevelAccessor level, BlockPos pos, Direction spreadDirection, boolean markForPostprocessing) {
		return Direction.stream()
			.map(direction2 -> this.spreadFromFaceTowardDirection(state, level, pos, spreadDirection, direction2, markForPostprocessing))
			.filter(Optional::isPresent)
			.count();
	}

	@VisibleForTesting
	public Optional<MultifaceSpreader.SpreadPos> spreadFromFaceTowardDirection(
		BlockState state, LevelAccessor level, BlockPos pos, Direction spreadDirection, Direction face, boolean markForPostprocessing
	) {
		return this.getSpreadFromFaceTowardDirection(state, level, pos, spreadDirection, face, this.config::canSpreadInto)
			.flatMap(spreadPos -> this.spreadToFace(level, spreadPos, markForPostprocessing));
	}

	public Optional<MultifaceSpreader.SpreadPos> getSpreadFromFaceTowardDirection(
		BlockState state, BlockGetter level, BlockPos pos, Direction spreadDirection, Direction face, MultifaceSpreader.SpreadPredicate predicate
	) {
		if (face.getAxis() == spreadDirection.getAxis()) {
			return Optional.empty();
		} else if (this.config.isOtherBlockValidAsSource(state) || this.config.hasFace(state, spreadDirection) && !this.config.hasFace(state, face)) {
			for (MultifaceSpreader.SpreadType spreadType : this.config.getSpreadTypes()) {
				MultifaceSpreader.SpreadPos spreadPos = spreadType.getSpreadPos(pos, face, spreadDirection);
				if (predicate.test(level, pos, spreadPos)) {
					return Optional.of(spreadPos);
				}
			}

			return Optional.empty();
		} else {
			return Optional.empty();
		}
	}

	public Optional<MultifaceSpreader.SpreadPos> spreadToFace(LevelAccessor level, MultifaceSpreader.SpreadPos pos, boolean markForPostprocessing) {
		BlockState blockState = level.getBlockState(pos.pos());
		return this.config.placeBlock(level, pos, blockState, markForPostprocessing) ? Optional.of(pos) : Optional.empty();
	}

	public static class DefaultSpreaderConfig implements MultifaceSpreader.SpreadConfig {
		protected MultifaceBlock block;

		public DefaultSpreaderConfig(MultifaceBlock block) {
			this.block = block;
		}

		@Nullable
		@Override
		public BlockState getStateForPlacement(BlockState currentState, BlockGetter level, BlockPos pos, Direction lookingDirection) {
			return this.block.getStateForPlacement(currentState, level, pos, lookingDirection);
		}

		protected boolean stateCanBeReplaced(BlockGetter level, BlockPos pos, BlockPos spreadPos, Direction direction, BlockState state) {
			return state.isAir() || state.is(this.block) || state.is(Blocks.WATER) && state.getFluidState().isSource();
		}

		@Override
		public boolean canSpreadInto(BlockGetter level, BlockPos pos, MultifaceSpreader.SpreadPos spreadPos) {
			BlockState blockState = level.getBlockState(spreadPos.pos());
			return this.stateCanBeReplaced(level, pos, spreadPos.pos(), spreadPos.face(), blockState)
				&& this.block.isValidStateForPlacement(level, blockState, spreadPos.pos(), spreadPos.face());
		}
	}

	public interface SpreadConfig {
		@Nullable
		BlockState getStateForPlacement(BlockState currentState, BlockGetter level, BlockPos pos, Direction lookingDirection);

		boolean canSpreadInto(BlockGetter level, BlockPos pos, MultifaceSpreader.SpreadPos spreadPos);

		default MultifaceSpreader.SpreadType[] getSpreadTypes() {
			return MultifaceSpreader.DEFAULT_SPREAD_ORDER;
		}

		default boolean hasFace(BlockState state, Direction direction) {
			return MultifaceBlock.hasFace(state, direction);
		}

		default boolean isOtherBlockValidAsSource(BlockState otherBlock) {
			return false;
		}

		default boolean canSpreadFrom(BlockState state, Direction direction) {
			return this.isOtherBlockValidAsSource(state) || this.hasFace(state, direction);
		}

		default boolean placeBlock(LevelAccessor level, MultifaceSpreader.SpreadPos pos, BlockState state, boolean markForPostprocessing) {
			BlockState blockState = this.getStateForPlacement(state, level, pos.pos(), pos.face());
			if (blockState != null) {
				if (markForPostprocessing) {
					level.getChunk(pos.pos()).markPosForPostprocessing(pos.pos());
				}

				return level.setBlock(pos.pos(), blockState, 2);
			} else {
				return false;
			}
		}
	}

	public record SpreadPos(BlockPos pos, Direction face) {
	}

	@FunctionalInterface
	public interface SpreadPredicate {
		boolean test(BlockGetter blockGetter, BlockPos blockPos, MultifaceSpreader.SpreadPos spreadPos);
	}

	public static enum SpreadType {
		SAME_POSITION {
			@Override
			public MultifaceSpreader.SpreadPos getSpreadPos(BlockPos pos, Direction face, Direction spreadDirection) {
				return new MultifaceSpreader.SpreadPos(pos, face);
			}
		},
		SAME_PLANE {
			@Override
			public MultifaceSpreader.SpreadPos getSpreadPos(BlockPos pos, Direction face, Direction spreadDirection) {
				return new MultifaceSpreader.SpreadPos(pos.relative(face), spreadDirection);
			}
		},
		WRAP_AROUND {
			@Override
			public MultifaceSpreader.SpreadPos getSpreadPos(BlockPos pos, Direction face, Direction spreadDirection) {
				return new MultifaceSpreader.SpreadPos(pos.relative(face).relative(spreadDirection), face.getOpposite());
			}
		};

		public abstract MultifaceSpreader.SpreadPos getSpreadPos(BlockPos pos, Direction face, Direction spreadDirection);
	}
}