package net.minecraft.world.level.levelgen.placement;

import com.mojang.serialization.MapCodec;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import java.util.List;
import java.util.stream.Stream;
import net.minecraft.core.BlockPos;
import net.minecraft.core.SectionPos;
import net.minecraft.util.RandomSource;

public class FixedPlacement extends PlacementModifier {
	public static final MapCodec<FixedPlacement> CODEC = RecordCodecBuilder.mapCodec(
		i -> i.group(BlockPos.CODEC.listOf().fieldOf("positions").forGetter(c -> c.positions)).apply(i, FixedPlacement::new)
	);
	private final List<BlockPos> positions;

	public static FixedPlacement of(final BlockPos... pos) {
		return new FixedPlacement(List.of(pos));
	}

	private FixedPlacement(final List<BlockPos> positions) {
		this.positions = positions;
	}

	@Override
	public Stream<BlockPos> getPositions(final PlacementContext context, final RandomSource random, final BlockPos origin) {
		int chunkX = SectionPos.blockToSectionCoord(origin.getX());
		int chunkZ = SectionPos.blockToSectionCoord(origin.getZ());
		boolean hasPositions = false;

		for (BlockPos position : this.positions) {
			if (isSameChunk(chunkX, chunkZ, position)) {
				hasPositions = true;
				break;
			}
		}

		return !hasPositions ? Stream.empty() : this.positions.stream().filter(pos -> isSameChunk(chunkX, chunkZ, pos));
	}

	private static boolean isSameChunk(final int chunkX, final int chunkZ, final BlockPos position) {
		return chunkX == SectionPos.blockToSectionCoord(position.getX()) && chunkZ == SectionPos.blockToSectionCoord(position.getZ());
	}

	@Override
	public PlacementModifierType<?> type() {
		return PlacementModifierType.FIXED_PLACEMENT;
	}
}