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

import com.mojang.datafixers.util.Either;
import com.mojang.serialization.Codec;
import com.mojang.serialization.MapCodec;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import java.util.Optional;
import java.util.function.IntFunction;
import net.minecraft.core.BlockPos;
import net.minecraft.util.ByIdMap;
import net.minecraft.util.Mth;
import net.minecraft.util.StringRepresentable;
import net.minecraft.world.level.ChunkPos;
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.chunk.ChunkGenerator;
import net.minecraft.world.level.levelgen.Heightmap;
import net.minecraft.world.level.levelgen.WorldgenRandom;
import net.minecraft.world.level.levelgen.structure.Structure;
import net.minecraft.world.level.levelgen.structure.StructureType;
import net.minecraft.world.level.levelgen.structure.pieces.StructurePiecesBuilder;

public class MineshaftStructure extends Structure {
	public static final MapCodec<MineshaftStructure> CODEC = RecordCodecBuilder.mapCodec(
		i -> i.group(settingsCodec(i), MineshaftStructure.Type.CODEC.fieldOf("mineshaft_type").forGetter(c -> c.type)).apply(i, MineshaftStructure::new)
	);
	private final MineshaftStructure.Type type;

	public MineshaftStructure(final Structure.StructureSettings settings, final MineshaftStructure.Type type) {
		super(settings);
		this.type = type;
	}

	@Override
	public Optional<Structure.GenerationStub> findGenerationPoint(final Structure.GenerationContext context) {
		context.random().nextDouble();
		ChunkPos chunkPos = context.chunkPos();
		BlockPos startPos = new BlockPos(chunkPos.getMiddleBlockX(), 50, chunkPos.getMinBlockZ());
		StructurePiecesBuilder mineshaftPiecesBuilder = new StructurePiecesBuilder();
		int yOffset = this.generatePiecesAndAdjust(mineshaftPiecesBuilder, context);
		return Optional.of(new Structure.GenerationStub(startPos.offset(0, yOffset, 0), Either.right(mineshaftPiecesBuilder)));
	}

	private int generatePiecesAndAdjust(final StructurePiecesBuilder builder, final Structure.GenerationContext context) {
		ChunkPos chunkPos = context.chunkPos();
		WorldgenRandom random = context.random();
		ChunkGenerator chunkGenerator = context.chunkGenerator();
		MineshaftPieces.MineShaftRoom mineShaftRoom = new MineshaftPieces.MineShaftRoom(0, random, chunkPos.getBlockX(2), chunkPos.getBlockZ(2), this.type);
		builder.addPiece(mineShaftRoom);
		mineShaftRoom.addChildren(mineShaftRoom, builder, random);
		int seaLevel = chunkGenerator.getSeaLevel();
		if (this.type == MineshaftStructure.Type.MESA) {
			BlockPos center = builder.getBoundingBox().getCenter();
			int surfaceHeight = chunkGenerator.getBaseHeight(
				center.getX(), center.getZ(), Heightmap.Types.WORLD_SURFACE_WG, context.heightAccessor(), context.randomState()
			);
			int targetYForCenter = surfaceHeight <= seaLevel ? seaLevel : Mth.randomBetweenInclusive(random, seaLevel, surfaceHeight);
			int dy = targetYForCenter - center.getY();
			builder.offsetPiecesVertically(dy);
			return dy;
		} else {
			return builder.moveBelowSeaLevel(seaLevel, chunkGenerator.getMinY(), random, 10);
		}
	}

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

	public static enum Type implements StringRepresentable {
		NORMAL("normal", Blocks.OAK_LOG, Blocks.OAK_PLANKS, Blocks.OAK_FENCE),
		MESA("mesa", Blocks.DARK_OAK_LOG, Blocks.DARK_OAK_PLANKS, Blocks.DARK_OAK_FENCE);

		public static final Codec<MineshaftStructure.Type> CODEC = StringRepresentable.fromEnum(MineshaftStructure.Type::values);
		private static final IntFunction<MineshaftStructure.Type> BY_ID = ByIdMap.continuous(Enum::ordinal, values(), ByIdMap.OutOfBoundsStrategy.ZERO);
		private final String name;
		private final BlockState woodState;
		private final BlockState planksState;
		private final BlockState fenceState;

		private Type(final String name, final Block wood, final Block plank, final Block fence) {
			this.name = name;
			this.woodState = wood.defaultBlockState();
			this.planksState = plank.defaultBlockState();
			this.fenceState = fence.defaultBlockState();
		}

		public String getName() {
			return this.name;
		}

		public static MineshaftStructure.Type byId(final int id) {
			return (MineshaftStructure.Type)BY_ID.apply(id);
		}

		public BlockState getWoodState() {
			return this.woodState;
		}

		public BlockState getPlanksState() {
			return this.planksState;
		}

		public BlockState getFenceState() {
			return this.fenceState;
		}

		@Override
		public String getSerializedName() {
			return this.name;
		}
	}
}