package net.minecraft.world.level.biome;

import com.google.common.hash.Hashing;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Holder;
import net.minecraft.core.QuartPos;
import net.minecraft.util.LinearCongruentialGenerator;
import net.minecraft.util.Mth;

public class BiomeManager {
	public static final int CHUNK_CENTER_QUART = QuartPos.fromBlock(8);
	private static final int ZOOM_BITS = 2;
	private static final int ZOOM = 4;
	private static final int ZOOM_MASK = 3;
	private final BiomeManager.NoiseBiomeSource noiseBiomeSource;
	private final long biomeZoomSeed;

	public BiomeManager(BiomeManager.NoiseBiomeSource noiseBiomeSource, long biomeZoomSeed) {
		this.noiseBiomeSource = noiseBiomeSource;
		this.biomeZoomSeed = biomeZoomSeed;
	}

	public static long obfuscateSeed(long seed) {
		return Hashing.sha256().hashLong(seed).asLong();
	}

	public BiomeManager withDifferentSource(BiomeManager.NoiseBiomeSource newSource) {
		return new BiomeManager(newSource, this.biomeZoomSeed);
	}

	public Holder<Biome> getBiome(BlockPos pos) {
		int i = pos.getX() - 2;
		int j = pos.getY() - 2;
		int k = pos.getZ() - 2;
		int l = i >> 2;
		int m = j >> 2;
		int n = k >> 2;
		double d = (i & 3) / 4.0;
		double e = (j & 3) / 4.0;
		double f = (k & 3) / 4.0;
		int o = 0;
		double g = Double.POSITIVE_INFINITY;

		for (int p = 0; p < 8; p++) {
			boolean bl = (p & 4) == 0;
			boolean bl2 = (p & 2) == 0;
			boolean bl3 = (p & 1) == 0;
			int q = bl ? l : l + 1;
			int r = bl2 ? m : m + 1;
			int s = bl3 ? n : n + 1;
			double h = bl ? d : d - 1.0;
			double t = bl2 ? e : e - 1.0;
			double u = bl3 ? f : f - 1.0;
			double v = getFiddledDistance(this.biomeZoomSeed, q, r, s, h, t, u);
			if (g > v) {
				o = p;
				g = v;
			}
		}

		int px = (o & 4) == 0 ? l : l + 1;
		int w = (o & 2) == 0 ? m : m + 1;
		int x = (o & 1) == 0 ? n : n + 1;
		return this.noiseBiomeSource.getNoiseBiome(px, w, x);
	}

	public Holder<Biome> getNoiseBiomeAtPosition(double x, double y, double z) {
		int i = QuartPos.fromBlock(Mth.floor(x));
		int j = QuartPos.fromBlock(Mth.floor(y));
		int k = QuartPos.fromBlock(Mth.floor(z));
		return this.getNoiseBiomeAtQuart(i, j, k);
	}

	public Holder<Biome> getNoiseBiomeAtPosition(BlockPos pos) {
		int i = QuartPos.fromBlock(pos.getX());
		int j = QuartPos.fromBlock(pos.getY());
		int k = QuartPos.fromBlock(pos.getZ());
		return this.getNoiseBiomeAtQuart(i, j, k);
	}

	public Holder<Biome> getNoiseBiomeAtQuart(int x, int y, int z) {
		return this.noiseBiomeSource.getNoiseBiome(x, y, z);
	}

	private static double getFiddledDistance(long seed, int x, int y, int z, double xNoise, double yNoise, double zNoise) {
		long l = LinearCongruentialGenerator.next(seed, x);
		l = LinearCongruentialGenerator.next(l, y);
		l = LinearCongruentialGenerator.next(l, z);
		l = LinearCongruentialGenerator.next(l, x);
		l = LinearCongruentialGenerator.next(l, y);
		l = LinearCongruentialGenerator.next(l, z);
		double d = getFiddle(l);
		l = LinearCongruentialGenerator.next(l, seed);
		double e = getFiddle(l);
		l = LinearCongruentialGenerator.next(l, seed);
		double f = getFiddle(l);
		return Mth.square(zNoise + f) + Mth.square(yNoise + e) + Mth.square(xNoise + d);
	}

	private static double getFiddle(long seed) {
		double d = Math.floorMod(seed >> 24, 1024) / 1024.0;
		return (d - 0.5) * 0.9;
	}

	public interface NoiseBiomeSource {
		/**
		 * Gets the biome at the given quart positions.
		 * Note that the coordinates passed into this method are 1/4 the scale of block coordinates.
		 */
		Holder<Biome> getNoiseBiome(int x, int y, int z);
	}
}