package net.minecraft.world.level.levelgen.structure.structures;

import com.mojang.serialization.MapCodec;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import java.util.Optional;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.world.level.EmptyBlockGetter;
import net.minecraft.world.level.NoiseColumn;
import net.minecraft.world.level.block.Blocks;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.levelgen.WorldGenerationContext;
import net.minecraft.world.level.levelgen.WorldgenRandom;
import net.minecraft.world.level.levelgen.heightproviders.HeightProvider;
import net.minecraft.world.level.levelgen.structure.Structure;
import net.minecraft.world.level.levelgen.structure.StructureType;

public class NetherFossilStructure extends Structure {
	public static final MapCodec<NetherFossilStructure> CODEC = RecordCodecBuilder.mapCodec(
		i -> i.group(settingsCodec(i), HeightProvider.CODEC.fieldOf("height").forGetter(c -> c.height)).apply(i, NetherFossilStructure::new)
	);
	public final HeightProvider height;

	public NetherFossilStructure(final Structure.StructureSettings settings, final HeightProvider height) {
		super(settings);
		this.height = height;
	}

	@Override
	public Optional<Structure.GenerationStub> findGenerationPoint(final Structure.GenerationContext context) {
		WorldgenRandom random = context.random();
		int blockX = context.chunkPos().getMinBlockX() + random.nextInt(16);
		int blockZ = context.chunkPos().getMinBlockZ() + random.nextInt(16);
		int seaLevel = context.chunkGenerator().getSeaLevel();
		WorldGenerationContext generationContext = new WorldGenerationContext(context.chunkGenerator(), context.heightAccessor());
		int y = this.height.sample(random, generationContext);
		NoiseColumn column = context.chunkGenerator().getBaseColumn(blockX, blockZ, context.heightAccessor(), context.randomState());
		BlockPos.MutableBlockPos pos = new BlockPos.MutableBlockPos(blockX, y, blockZ);

		while (y > seaLevel) {
			BlockState current = column.getBlock(y);
			BlockState below = column.getBlock(--y);
			if (current.isAir() && (below.is(Blocks.SOUL_SAND) || below.isFaceSturdy(EmptyBlockGetter.INSTANCE, pos.setY(y), Direction.UP))) {
				break;
			}
		}

		if (y <= seaLevel) {
			return Optional.empty();
		} else {
			BlockPos position = new BlockPos(blockX, y, blockZ);
			return Optional.of(
				new Structure.GenerationStub(position, builder -> NetherFossilPieces.addPieces(context.structureTemplateManager(), builder, random, position))
			);
		}
	}

	@Override
	public StructureType<?> type() {
		return StructureType.NETHER_FOSSIL;
	}
}