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

import com.mojang.serialization.Codec;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Vec3i;
import net.minecraft.resources.Identifier;
import net.minecraft.util.RandomSource;
import net.minecraft.world.level.ChunkPos;
import net.minecraft.world.level.WorldGenLevel;
import net.minecraft.world.level.block.Blocks;
import net.minecraft.world.level.block.Mirror;
import net.minecraft.world.level.block.Rotation;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.levelgen.Heightmap;
import net.minecraft.world.level.levelgen.structure.BoundingBox;
import net.minecraft.world.level.levelgen.structure.templatesystem.StructurePlaceSettings;
import net.minecraft.world.level.levelgen.structure.templatesystem.StructureTemplate;
import net.minecraft.world.level.levelgen.structure.templatesystem.StructureTemplateManager;
import org.apache.commons.lang3.mutable.MutableInt;

public class FossilFeature extends Feature<FossilFeatureConfiguration> {
	public FossilFeature(final Codec<FossilFeatureConfiguration> codec) {
		super(codec);
	}

	@Override
	public boolean place(final FeaturePlaceContext<FossilFeatureConfiguration> context) {
		RandomSource random = context.random();
		WorldGenLevel level = context.level();
		BlockPos origin = context.origin();
		Rotation rotation = Rotation.getRandom(random);
		FossilFeatureConfiguration config = context.config();
		int fossilIndex = random.nextInt(config.fossilStructures.size());
		StructureTemplateManager structureTemplateManager = level.getLevel().getServer().getStructureManager();
		StructureTemplate fossilBase = structureTemplateManager.getOrCreate((Identifier)config.fossilStructures.get(fossilIndex));
		StructureTemplate fossilOverlay = structureTemplateManager.getOrCreate((Identifier)config.overlayStructures.get(fossilIndex));
		ChunkPos chunkPos = ChunkPos.containing(origin);
		BoundingBox boundingBox = new BoundingBox(
			chunkPos.getMinBlockX() - 16, level.getMinY(), chunkPos.getMinBlockZ() - 16, chunkPos.getMaxBlockX() + 16, level.getMaxY(), chunkPos.getMaxBlockZ() + 16
		);
		StructurePlaceSettings settings = new StructurePlaceSettings().setRotation(rotation).setBoundingBox(boundingBox).setRandom(random);
		Vec3i size = fossilBase.getSize(rotation);
		BlockPos lowCorner = origin.offset(-size.getX() / 2, 0, -size.getZ() / 2);
		int lowestSurfaceY = origin.getY();

		for (int xscan = 0; xscan < size.getX(); xscan++) {
			for (int zscan = 0; zscan < size.getZ(); zscan++) {
				lowestSurfaceY = Math.min(lowestSurfaceY, level.getHeight(Heightmap.Types.OCEAN_FLOOR_WG, lowCorner.getX() + xscan, lowCorner.getZ() + zscan));
			}
		}

		int targetY = Math.max(lowestSurfaceY - 15 - random.nextInt(10), level.getMinY() + 10);
		BlockPos targetPos = fossilBase.getZeroPositionWithTransform(lowCorner.atY(targetY), Mirror.NONE, rotation);
		if (countEmptyCorners(level, fossilBase.getBoundingBox(settings, targetPos)) > config.maxEmptyCornersAllowed) {
			return false;
		} else {
			settings.clearProcessors();
			config.fossilProcessors.value().list().forEach(settings::addProcessor);
			fossilBase.placeInWorld(level, targetPos, targetPos, settings, random, 260);
			settings.clearProcessors();
			config.overlayProcessors.value().list().forEach(settings::addProcessor);
			fossilOverlay.placeInWorld(level, targetPos, targetPos, settings, random, 260);
			return true;
		}
	}

	private static int countEmptyCorners(final WorldGenLevel level, final BoundingBox structureBounds) {
		MutableInt count = new MutableInt(0);
		structureBounds.forAllCorners(pos -> {
			BlockState state = level.getBlockState(pos);
			if (state.isAir() || state.is(Blocks.LAVA) || state.is(Blocks.WATER)) {
				count.add(1);
			}
		});
		return count.intValue();
	}
}