import {MASK, int32s2bytes, bytes2int32s, zeroPad} from "./util.js";

const BLOCK_LEN = 64;

const IV = [0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A, 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19];

function rrot(x, shift) {

	return ((x >>> shift) | (x << (32-shift))) & MASK;

export function BLAKE2S(outputLen = 32, key = []) {

	this._buffer = [];

	this._dataLen = [0, 0]; // low, high

	this._outputLen = outputLen;

	this._state = IV.slice();

	this._state[0] ^= 0x01010000 ^ (key.length << 8) ^ this._outputLen;

	if (key.length > 0) {this.update(zeroPad(key, BLOCK_LEN));}

BLAKE2S.prototype.update = function (data) {

	for (let i = 0; i < data.length; i++) {

		if (this._buffer.length == BLOCK_LEN) {

			this._buffer = [];

		this._dataLen[0] = (this._dataLen[0]+1) & MASK;

		if (this._dataLen[0] < this._buffer.length) {this._dataLen[1]++;}

BLAKE2S.prototype.digest = function () {

	this._buffer = zeroPad(this._buffer, BLOCK_LEN);

	return int32s2bytes(this._state).slice(0, this._outputLen);

BLAKE2S.prototype._compress = function (last) {

	const SIGMA = [

		[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15],

		[14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3],

		[11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4],

		[7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8],

		[9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13],

		[2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9],

		[12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11],

		[13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10],

		[6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5],

		[10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0]

	let v = this._state.concat(IV);

	v[12] ^= this._dataLen[0];

	v[13] ^= this._dataLen[1];

	if (last) {v[14] ^= MASK;}

	let data = bytes2int32s(this._buffer);

	for (let i = 0; i < 10; i++) {

		let perm = SIGMA[i % 10];

		this._mix(v, 0, 4, 8, 12, data[perm[0]], data[perm[1]]);

		this._mix(v, 1, 5, 9, 13, data[perm[2]], data[perm[3]]);

		this._mix(v, 2, 6, 10, 14, data[perm[4]], data[perm[5]]);

		this._mix(v, 3, 7, 11, 15, data[perm[6]], data[perm[7]]);

		this._mix(v, 0, 5, 10, 15, data[perm[8]], data[perm[9]]);

		this._mix(v, 1, 6, 11, 12, data[perm[10]], data[perm[11]]);

		this._mix(v, 2, 7, 8, 13, data[perm[12]], data[perm[13]]);

		this._mix(v, 3, 4, 9, 14, data[perm[14]], data[perm[15]]);

	this._state = this._state.map((x, i) => x ^ v[i] ^ v[i+8]);

BLAKE2S.prototype._mix = function (arr, ia, ib, ic, id, x, y) {

	let a = arr[ia], b = arr[ib], c = arr[ic], d = arr[id];

	a = (a + b + x) & MASK; d = rrot(d ^ a, 16);

	c = (c + d) & MASK; b = rrot(b ^ c, 12);

	a = (a + b + y) & MASK; d = rrot(d ^ a, 8);

	c = (c + d) & MASK; b = rrot(b ^ c, 7);

	arr[ia] = a; arr[ib] = b; arr[ic] = c; arr[id] = d;

export function blake2s(data, outputLen = 32, key = []) {

	let h = new BLAKE2S(outputLen, key);

	for (let i = 0; i < data.length; i += BLOCK_LEN) {

		h.update(data.slice(i, i + BLOCK_LEN));

	}