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

import com.mojang.logging.LogUtils;
import com.mojang.serialization.Codec;
import com.mojang.serialization.MapCodec;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import net.minecraft.util.RandomSource;
import net.minecraft.world.level.levelgen.VerticalAnchor;
import net.minecraft.world.level.levelgen.WorldGenerationContext;
import org.slf4j.Logger;

public class BiasedToBottomHeight extends HeightProvider {
	public static final MapCodec<BiasedToBottomHeight> CODEC = RecordCodecBuilder.mapCodec(
		i -> i.group(
				VerticalAnchor.CODEC.fieldOf("min_inclusive").forGetter(u -> u.minInclusive),
				VerticalAnchor.CODEC.fieldOf("max_inclusive").forGetter(u -> u.maxInclusive),
				Codec.intRange(1, Integer.MAX_VALUE).optionalFieldOf("inner", 1).forGetter(u -> u.inner)
			)
			.apply(i, BiasedToBottomHeight::new)
	);
	private static final Logger LOGGER = LogUtils.getLogger();
	private final VerticalAnchor minInclusive;
	private final VerticalAnchor maxInclusive;
	private final int inner;

	private BiasedToBottomHeight(final VerticalAnchor minInclusive, final VerticalAnchor maxInclusive, final int inner) {
		this.minInclusive = minInclusive;
		this.maxInclusive = maxInclusive;
		this.inner = inner;
	}

	public static BiasedToBottomHeight of(final VerticalAnchor minInclusive, final VerticalAnchor maxInclusive, final int offset) {
		return new BiasedToBottomHeight(minInclusive, maxInclusive, offset);
	}

	@Override
	public int sample(final RandomSource random, final WorldGenerationContext context) {
		int min = this.minInclusive.resolveY(context);
		int max = this.maxInclusive.resolveY(context);
		if (max - min - this.inner + 1 <= 0) {
			LOGGER.warn("Empty height range: {}", this);
			return min;
		} else {
			int limit = random.nextInt(max - min - this.inner + 1);
			return random.nextInt(limit + this.inner) + min;
		}
	}

	@Override
	public HeightProviderType<?> getType() {
		return HeightProviderType.BIASED_TO_BOTTOM;
	}

	public String toString() {
		return "biased[" + this.minInclusive + "-" + this.maxInclusive + " inner: " + this.inner + "]";
	}
}