package net.devtech.biome;

import javax.imageio.ImageIO;
import java.awt.Color;
import java.awt.Desktop;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import static net.devtech.Rand.next;
import static net.devtech.Rand.seed;

public class BiomeGen {
	private final int power;
	private final int size;
	private final int mod;

	public BiomeGen(int power) {
		this.power = power;
		this.size = 1 << power;
		this.mod = size - 1;
	}

	public int getBiome(int x, int y) {
		int rx = x >>> power;
		int ry = y >>> power;

		int current = compute(rx, ry, x, y);
		int next;

		int offsetx = 0;
		int offsety = 0;

		if ((next = compute(rx - 1, ry, x, y)) < current) {
			offsetx = -1;
			offsety = 0;
			current = next;
		}
		if ((next = compute(rx, ry + 1, x, y)) < current) {
			offsetx = 0;
			offsety = 1;
			current = next;
		}
		if ((next = compute(rx + 1, ry, x, y)) < current) {
			offsetx = 1;
			offsety = 0;
			current = next;
		}
		if ((next = compute(rx, ry - 1, x, y)) < current) {
			offsetx = 0;
			offsety = -1;
			current = next;
		}
		if ((next = compute(rx - 1, ry - 1, x, y)) < current) {
			offsetx = -1;
			offsety = -1;
			current = next;
		}
		if ((next = compute(rx + 1, ry + 1, x, y)) < current) {
			offsetx = 1;
			offsety = 1;
			current = next;
		}
		if ((next = compute(rx + 1, ry - 1, x, y)) < current) {
			offsetx = 1;
			offsety = -1;
			current = next;
		}
		if (compute(rx - 1, ry + 1, x, y) < current) {
			offsetx = -1;
			offsety = 1;
		}

		return next(seed(rx + offsetx, ry + offsety));
	}

	private int compute(int rx, int ry, int x, int y) {
		long[] arr = {seed(rx, ry)};
		int ox = rx * size + (next(arr) & mod) - x;
		int oy = ry * size + (next(arr) & mod) - y;
		return ox * ox + oy * oy;
	}

	public static void main(String[] args) throws IOException {
		BiomeGen gen = new BiomeGen(6);
		final int size = 2048;
		BufferedImage image = new BufferedImage(size, size, BufferedImage.TYPE_4BYTE_ABGR);
		for (int i = 0; i < size; i++)
			for (int i1 = 0; i1 < size; i1++)
				image.setRGB(i, i1, new Color((gen.getBiome(i1, i)) & 255, (gen.getBiome(i1, i)) & 255, (gen.getBiome(i1, i)) & 255, (((gen.getBiome(i1, i)) & 255) == 0) ? 0 : 255).getRGB());
		File temp = File.createTempFile("bruh", ".png");
		ImageIO.write(image, "png", temp);
		Desktop.getDesktop().open(temp);
	}
}