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

import com.google.common.collect.ImmutableList;
import com.mojang.serialization.Codec;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.util.RandomSource;
import net.minecraft.world.level.LevelAccessor;
import net.minecraft.world.level.WorldGenLevel;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.block.Blocks;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.levelgen.feature.configurations.DeltaFeatureConfiguration;

public class DeltaFeature extends Feature<DeltaFeatureConfiguration> {
	private static final ImmutableList<Block> CANNOT_REPLACE = ImmutableList.of(
		Blocks.BEDROCK, Blocks.NETHER_BRICKS, Blocks.NETHER_BRICK_FENCE, Blocks.NETHER_BRICK_STAIRS, Blocks.NETHER_WART, Blocks.CHEST, Blocks.SPAWNER
	);
	private static final Direction[] DIRECTIONS = Direction.values();
	private static final double RIM_SPAWN_CHANCE = 0.9;

	public DeltaFeature(final Codec<DeltaFeatureConfiguration> codec) {
		super(codec);
	}

	@Override
	public boolean place(final FeaturePlaceContext<DeltaFeatureConfiguration> context) {
		boolean anyPlaced = false;
		RandomSource random = context.random();
		WorldGenLevel level = context.level();
		DeltaFeatureConfiguration config = context.config();
		BlockPos origin = context.origin();
		boolean spawnRim = random.nextDouble() < 0.9;
		int rimX = spawnRim ? config.rimSize().sample(random) : 0;
		int rimZ = spawnRim ? config.rimSize().sample(random) : 0;
		boolean hasRim = spawnRim && rimX != 0 && rimZ != 0;
		int radiusX = config.size().sample(random);
		int radiusZ = config.size().sample(random);
		int radiusLimit = Math.max(radiusX, radiusZ);

		for (BlockPos pos : BlockPos.withinManhattan(origin, radiusX, 0, radiusZ)) {
			if (pos.distManhattan(origin) > radiusLimit) {
				break;
			}

			if (isClear(level, pos, config)) {
				if (hasRim) {
					anyPlaced = true;
					this.setBlock(level, pos, config.rim());
				}

				BlockPos posOffset = pos.offset(rimX, 0, rimZ);
				if (isClear(level, posOffset, config)) {
					anyPlaced = true;
					this.setBlock(level, posOffset, config.contents());
				}
			}
		}

		return anyPlaced;
	}

	private static boolean isClear(final LevelAccessor level, final BlockPos pos, final DeltaFeatureConfiguration config) {
		BlockState state = level.getBlockState(pos);
		if (state.is(config.contents().getBlock())) {
			return false;
		} else if (CANNOT_REPLACE.contains(state.getBlock())) {
			return false;
		} else {
			for (Direction d : DIRECTIONS) {
				boolean isAir = level.getBlockState(pos.relative(d)).isAir();
				if (isAir && d != Direction.UP || !isAir && d == Direction.UP) {
					return false;
				}
			}

			return true;
		}
	}
}