<?php

/*
 *
 *  ____            _        _   __  __ _                  __  __ ____
 * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
 * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
 * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
 * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * @author PocketMine Team
 * @link http://www.pocketmine.net/
 *
 *
*/

declare(strict_types=1);

namespace pocketmine\level\generator\noise;

use pocketmine\utils\Random;

class Perlin extends Noise{
	/** @var int[][] */
	public static $grad3 = [
		[1, 1, 0], [-1, 1, 0], [1, -1, 0], [-1, -1, 0],
		[1, 0, 1], [-1, 0, 1], [1, 0, -1], [-1, 0, -1],
		[0, 1, 1], [0, -1, 1], [0, 1, -1], [0, -1, -1]
	];

	/**
	 * @param int    $octaves
	 * @param float  $persistence
	 * @param float  $expansion
	 */
	public function __construct(Random $random, $octaves, $persistence, $expansion = 1){
		$this->octaves = $octaves;
		$this->persistence = $persistence;
		$this->expansion = $expansion;
		$this->offsetX = $random->nextFloat() * 256;
		$this->offsetY = $random->nextFloat() * 256;
		$this->offsetZ = $random->nextFloat() * 256;

		for($i = 0; $i < 512; ++$i){
			$this->perm[$i] = 0;
		}

		for($i = 0; $i < 256; ++$i){
			$this->perm[$i] = $random->nextBoundedInt(256);
		}

		for($i = 0; $i < 256; ++$i){
			$pos = $random->nextBoundedInt(256 - $i) + $i;
			$old = $this->perm[$i];

			$this->perm[$i] = $this->perm[$pos];
			$this->perm[$pos] = $old;
			$this->perm[$i + 256] = $this->perm[$i];
		}

	}

	public function getNoise3D($x, $y, $z){
		$x += $this->offsetX;
		$y += $this->offsetY;
		$z += $this->offsetZ;

		$floorX = (int) $x;
		$floorY = (int) $y;
		$floorZ = (int) $z;

		$X = $floorX & 0xFF;
		$Y = $floorY & 0xFF;
		$Z = $floorZ & 0xFF;

		$x -= $floorX;
		$y -= $floorY;
		$z -= $floorZ;

		//Fade curves
		//$fX = self::fade($x);
		//$fY = self::fade($y);
		//$fZ = self::fade($z);
		$fX = $x * $x * $x * ($x * ($x * 6 - 15) + 10);
		$fY = $y * $y * $y * ($y * ($y * 6 - 15) + 10);
		$fZ = $z * $z * $z * ($z * ($z * 6 - 15) + 10);

		//Cube corners
		$A = $this->perm[$X] + $Y;
		$B = $this->perm[$X + 1] + $Y;

		$AA = $this->perm[$A] + $Z;
		$AB = $this->perm[$A + 1] + $Z;
		$BA = $this->perm[$B] + $Z;
		$BB = $this->perm[$B + 1] + $Z;

		$AA1 = self::grad($this->perm[$AA], $x, $y, $z);
		$BA1 = self::grad($this->perm[$BA], $x - 1, $y, $z);
		$AB1 = self::grad($this->perm[$AB], $x, $y - 1, $z);
		$BB1 = self::grad($this->perm[$BB], $x - 1, $y - 1, $z);
		$AA2 = self::grad($this->perm[$AA + 1], $x, $y, $z - 1);
		$BA2 = self::grad($this->perm[$BA + 1], $x - 1, $y, $z - 1);
		$AB2 = self::grad($this->perm[$AB + 1], $x, $y - 1, $z - 1);
		$BB2 = self::grad($this->perm[$BB + 1], $x - 1, $y - 1, $z - 1);

		$xLerp11 = $AA1 + $fX * ($BA1 - $AA1);

		$zLerp1 = $xLerp11 + $fY * ($AB1 + $fX * ($BB1 - $AB1) - $xLerp11);

		$xLerp21 = $AA2 + $fX * ($BA2 - $AA2);

		return $zLerp1 + $fZ * ($xLerp21 + $fY * ($AB2 + $fX * ($BB2 - $AB2) - $xLerp21) - $zLerp1);

		/*
		return self::lerp(
			$fZ,
			self::lerp(
				$fY,
				self::lerp(
					$fX,
					self::grad($this->perm[$AA], $x, $y, $z),
					self::grad($this->perm[$BA], $x - 1, $y, $z)
				),
				self::lerp(
					$fX,
					self::grad($this->perm[$AB], $x, $y - 1, $z),
					self::grad($this->perm[$BB], $x - 1, $y - 1, $z)
				)
			),
			self::lerp(
				$fY,
				self::lerp(
					$fX,
					self::grad($this->perm[$AA + 1], $x, $y, $z - 1),
					self::grad($this->perm[$BA + 1], $x - 1, $y, $z - 1)
				),
				self::lerp(
					$fX,
					self::grad($this->perm[$AB + 1], $x, $y - 1, $z - 1),
					self::grad($this->perm[$BB + 1], $x - 1, $y - 1, $z - 1)
				)
			)
		);
		*/
	}

	/**
	 * @param float $x
	 * @param float $y
	 *
	 * @return float
	 */
	public function getNoise2D($x, $y){
		return $this->getNoise3D($x, $y, 0);
	}
}