// http://mrl.nyu.edu/~perlin/noise/

const ImprovedNoise = function () {
    const p = [151, 160, 137, 91, 90, 15, 131, 13, 201, 95, 96, 53, 194, 233, 7, 225, 140, 36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10,
        23, 190, 6, 148, 247, 120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32, 57, 177, 33, 88, 237, 149, 56, 87,
        174, 20, 125, 136, 171, 168, 68, 175, 74, 165, 71, 134, 139, 48, 27, 166, 77, 146, 158, 231, 83, 111, 229, 122, 60, 211,
        133, 230, 220, 105, 92, 41, 55, 46, 245, 40, 244, 102, 143, 54, 65, 25, 63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208,
        89, 18, 169, 200, 196, 135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3, 64, 52, 217, 226, 250, 124, 123, 5,
        202, 38, 147, 118, 126, 255, 82, 85, 212, 207, 206, 59, 227, 47, 16, 58, 17, 182, 189, 28, 42, 223, 183, 170, 213, 119,
        248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9, 129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232,
        178, 185, 112, 104, 218, 246, 97, 228, 251, 34, 242, 193, 238, 210, 144, 12, 191, 179, 162, 241, 81, 51, 145, 235, 249,
        14, 239, 107, 49, 192, 214, 31, 181, 199, 106, 157, 184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254, 138, 236, 205,
        93, 222, 114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180];

    for (let i = 0; i < 256; i++) {
        p[256 + i] = p[i];
    }

    function fade(t) {
        return t * t * t * (t * (t * 6 - 15) + 10);
    }

    function lerp(t, a, b) {
        return a + t * (b - a);
    }

    function grad(hash, x, y, z) {
        const h = hash & 15;
        const u = h < 8 ? x : y; const
            v = h < 4 ? y : h == 12 || h == 14 ? x : z;
        return ((h & 1) == 0 ? u : -u) + ((h & 2) == 0 ? v : -v);
    }

    return {

        noise(x, y, z) {
            const floorX = Math.floor(x); const floorY = Math.floor(y); const
                floorZ = Math.floor(z);

            const X = floorX & 255; const Y = floorY & 255; const
                Z = floorZ & 255;

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

            const xMinus1 = x - 1; const yMinus1 = y - 1; const
                zMinus1 = z - 1;

            const u = fade(x); const v = fade(y); const
                w = fade(z);

            const A = p[X] + Y; const AA = p[A] + Z; const AB = p[A + 1] + Z; const B = p[X + 1] + Y; const BA = p[B] + Z; const
                BB = p[B + 1] + Z;

            return lerp(w, lerp(v, lerp(u, grad(p[AA], x, y, z),
                grad(p[BA], xMinus1, y, z)),
            lerp(u, grad(p[AB], x, yMinus1, z),
                grad(p[BB], xMinus1, yMinus1, z))),
            lerp(v, lerp(u, grad(p[AA + 1], x, y, zMinus1),
                grad(p[BA + 1], xMinus1, y, z - 1)),
            lerp(u, grad(p[AB + 1], x, yMinus1, zMinus1),
                grad(p[BB + 1], xMinus1, yMinus1, zMinus1))));
        },
    };
};

const currentRandom = Math.random;

// Pseudo-random generator
function Marsaglia(i1, i2) {
    // from http://www.math.uni-bielefeld.de/~sillke/ALGORITHMS/random/marsaglia-c
    let z = i1 || 362436069; let
        w = i2 || 521288629;
    const nextInt = function () {
        z = (36969 * (z & 65535) + (z >>> 16)) & 0xFFFFFFFF;
        w = (18000 * (w & 65535) + (w >>> 16)) & 0xFFFFFFFF;
        return (((z & 0xFFFF) << 16) | (w & 0xFFFF)) & 0xFFFFFFFF;
    };

    this.nextDouble = function () {
        const i = nextInt() / 4294967296;
        return i < 0 ? 1 + i : i;
    };
    this.nextInt = nextInt;
}
Marsaglia.createRandomized = function () {
    const now = new Date();
    return new Marsaglia((now / 60000) & 0xFFFFFFFF, now & 0xFFFFFFFF);
};

// Noise functions and helpers
function PerlinNoise(seed) {
    const rnd = seed !== undefined ? new Marsaglia(seed) : Marsaglia.createRandomized();
    let i; let
        j;
    // http://www.noisemachine.com/talk1/17b.html
    // http://mrl.nyu.edu/~perlin/noise/
    // generate permutation
    const p = new Array(512);
    for (i = 0; i < 256; ++i) { p[i] = i; }
    for (i = 0; i < 256; ++i) { const t = p[j = rnd.nextInt() & 0xFF]; p[j] = p[i]; p[i] = t; }
    // copy to avoid taking mod in p[0];
    for (i = 0; i < 256; ++i) { p[i + 256] = p[i]; }

    function grad3d(i, x, y, z) {
        const h = i & 15; // convert into 12 gradient directions
        const u = h < 8 ? x : y;


        const v = h < 4 ? y : h === 12 || h === 14 ? x : z;
        return ((h & 1) === 0 ? u : -u) + ((h & 2) === 0 ? v : -v);
    }

    function grad2d(i, x, y) {
        const v = (i & 1) === 0 ? x : y;
        return (i & 2) === 0 ? -v : v;
    }

    function grad1d(i, x) {
        return (i & 1) === 0 ? -x : x;
    }

    function lerp(t, a, b) { return a + t * (b - a); }

    this.noise3d = function (x, y, z) {
        const X = Math.floor(x) & 255; const Y = Math.floor(y) & 255; const
            Z = Math.floor(z) & 255;
        x -= Math.floor(x); y -= Math.floor(y); z -= Math.floor(z);
        const fx = (3 - 2 * x) * x * x; const fy = (3 - 2 * y) * y * y; const
            fz = (3 - 2 * z) * z * z;
        const p0 = p[X] + Y; const p00 = p[p0] + Z; const p01 = p[p0 + 1] + Z; const p1  = p[X + 1] + Y; const p10 = p[p1] + Z; const
            p11 = p[p1 + 1] + Z;
        return lerp(fz,
            lerp(fy, lerp(fx, grad3d(p[p00], x, y, z), grad3d(p[p10], x - 1, y, z)),
                lerp(fx, grad3d(p[p01], x, y - 1, z), grad3d(p[p11], x - 1, y - 1, z))),
            lerp(fy, lerp(fx, grad3d(p[p00 + 1], x, y, z - 1), grad3d(p[p10 + 1], x - 1, y, z - 1)),
                lerp(fx, grad3d(p[p01 + 1], x, y - 1, z - 1), grad3d(p[p11 + 1], x - 1, y - 1, z - 1))));
    };

    this.noise2d = function (x, y) {
        const X = Math.floor(x) & 255; const
            Y = Math.floor(y) & 255;
        x -= Math.floor(x); y -= Math.floor(y);
        const fx = (3 - 2 * x) * x * x; const
            fy = (3 - 2 * y) * y * y;
        const p0 = p[X] + Y; const
            p1  = p[X + 1] + Y;
        return lerp(fy,
            lerp(fx, grad2d(p[p0], x, y), grad2d(p[p1], x - 1, y)),
            lerp(fx, grad2d(p[p0 + 1], x, y - 1), grad2d(p[p1 + 1], x - 1, y - 1)));
    };

    this.noise1d = function (x) {
        const X = Math.floor(x) & 255;
        x -= Math.floor(x);
        const fx = (3 - 2 * x) * x * x;
        return lerp(fx, grad1d(p[X], x), grad1d(p[X + 1], x - 1));
    };
}

//  these are lifted from Processing.js
// processing defaults
const noiseProfile = {
    generator: undefined, octaves: 4, fallout: 0.5, seed: undefined,
};

module.exports = function noise(x, y, z) {
    if (noiseProfile.generator === undefined) {
    // caching
        noiseProfile.generator = new PerlinNoise(noiseProfile.seed);
    }
    const generator = noiseProfile.generator;
    let effect = 1; let k = 1; let
        sum = 0;
    for (let i = 0; i < noiseProfile.octaves; ++i) {
        effect *= noiseProfile.fallout;
        switch (arguments.length) {
        case 1:
            sum += effect * (1 + generator.noise1d(k * x)) / 2; break;
        case 2:
            sum += effect * (1 + generator.noise2d(k * x, k * y)) / 2; break;
        case 3:
            sum += effect * (1 + generator.noise3d(k * x, k * y, k * z)) / 2; break;
        }
        k *= 2;
    }
    return sum;
};
