// Loaded from https://raw.githubusercontent.com/aricart/tweetnacl-deno/import-type-fixes/src/blake2b.ts


// Blake2B in pure Javascript
// Adapted from the reference implementation in RFC7693
// Ported to Javascript by DC - https://github.com/dcposch

import { ByteArray, WordArray } from './array.ts';

export interface Blake2B {
    b: ByteArray;
    h: WordArray;
    t: number; // input count
    c: number; // pointer within buffer
    outlen: number; // output length in bytes
}

// Computes the BLAKE2B hash of a string or byte array, and returns a ByteArray
//
// Returns a n-byte ByteArray
//
// Parameters:
// - input - the input bytes, as a ByteArray
// - key - optional key ByteArray, up to 64 bytes
// - outlen - optional output length in bytes, default 64
export function blake2b(input: ByteArray, key?: ByteArray, outlen: number = 64) {
    const ctx: Blake2B = blake2b_init(outlen, key);

    blake2b_update(ctx, input);

    return blake2b_final(ctx)
}

// Creates a BLAKE2b hashing context
// Requires an output length between 1 and 64 bytes
// Takes an optional ByteArray key
export function blake2b_init(outlen: number, key?: ByteArray): Blake2B {
    if (outlen === 0 || outlen > 64)
        throw new Error('Illegal output length, expected 0 < length <= 64')

    if (key && key.length > 64)
        throw new Error('Illegal key, expected Uint8Array with 0 < length <= 64')

    // hash state
    const h = WordArray(16);

    // initialize hash state
    for (let i = 0; i < 16; i++) h[i] = BLAKE2B_IV32[i];

    const keylen = key ? key.length : 0;

    h[0] ^= 0x01010000 ^ (keylen << 8) ^ outlen;

    // state, 'param block'
    const ctx: Blake2B = {
        b: ByteArray(128),
        h,
        t: 0, // input count
        c: 0, // pointer within buffer
        outlen // output length in bytes
    };

    // key the hash, if applicable
    if (key) {
        blake2b_update(ctx, key);

        // at the end
        ctx.c = 128;
    }

    return ctx;
}

// Updates a BLAKE2b streaming hash
// Requires hash context and Uint8Array (byte array)
export function blake2b_update(ctx: Blake2B, input: ByteArray) {
    for (let i = 0; i < input.length; i++) {
        if (ctx.c === 128) { // buffer full ?
            ctx.t += ctx.c; // add counters
            blake2b_compress(ctx, false); // compress (not last)
            ctx.c = 0; // counter to zero
        }

        ctx.b[ctx.c++] = input[i];
    }
}

// Completes a BLAKE2b streaming hash
// Returns a Uint8Array containing the message digest
export function blake2b_final(ctx: Blake2B) {
    ctx.t += ctx.c; // mark last block offset

    while (ctx.c < 128) { // fill up with zeros
        ctx.b[ctx.c++] = 0;
    }

    blake2b_compress(ctx, true); // final block flag = 1

    // little endian convert and store
    const out = ByteArray(ctx.outlen);

    for (let i = 0; i < ctx.outlen; i++) {
        out[i] = ctx.h[i >> 2] >> (8 * (i & 3));
    }

    return out;
}

// Initialization Vector
const BLAKE2B_IV32 = WordArray([
    0xF3BCC908, 0x6A09E667, 0x84CAA73B, 0xBB67AE85,
    0xFE94F82B, 0x3C6EF372, 0x5F1D36F1, 0xA54FF53A,
    0xADE682D1, 0x510E527F, 0x2B3E6C1F, 0x9B05688C,
    0xFB41BD6B, 0x1F83D9AB, 0x137E2179, 0x5BE0CD19
])

const SIGMA8 = [
    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,
    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
];

// These are offsets into a uint64 buffer.
// Multiply them all by 2 to make them offsets into a uint32 buffer,
// because this is Javascript and we don't have uint64s
const SIGMA82 = ByteArray(SIGMA8.map(x => x * 2));

// Compression function. 'last' flag indicates last block.
// Note we're representing 16 uint64s as 32 uint32s
const v = WordArray(32);
const m = WordArray(32);

function blake2b_compress(ctx: Blake2B, last: boolean) {
    let i;

    // init work variables
    for (i = 0; i < 16; i++) {
        v[i] = ctx.h[i];
        v[i + 16] = BLAKE2B_IV32[i];
    }

    // low 64 bits of offset
    v[24] = v[24] ^ ctx.t;
    v[25] = v[25] ^ (ctx.t / 0x100000000);
    // high 64 bits not supported, offset may not be higher than 2**53-1

    // last block flag set ?
    if (last) {
        v[28] = ~v[28];
        v[29] = ~v[29];
    }

    // get little-endian words
    for (i = 0; i < 32; i++) {
        m[i] = B2B_GET32(ctx.h, 4 * i);
    }

    // twelve rounds of mixing
    // uncomment the DebugPrint calls to log the computation
    // and match the RFC sample documentation
    for (i = 0; i < 12; i++) {
        B2B_G(0, 8, 16, 24, SIGMA82[i * 16 + 0], SIGMA82[i * 16 + 1]);
        B2B_G(2, 10, 18, 26, SIGMA82[i * 16 + 2], SIGMA82[i * 16 + 3]);
        B2B_G(4, 12, 20, 28, SIGMA82[i * 16 + 4], SIGMA82[i * 16 + 5]);
        B2B_G(6, 14, 22, 30, SIGMA82[i * 16 + 6], SIGMA82[i * 16 + 7]);
        B2B_G(0, 10, 20, 30, SIGMA82[i * 16 + 8], SIGMA82[i * 16 + 9]);
        B2B_G(2, 12, 22, 24, SIGMA82[i * 16 + 10], SIGMA82[i * 16 + 11]);
        B2B_G(4, 14, 16, 26, SIGMA82[i * 16 + 12], SIGMA82[i * 16 + 13]);
        B2B_G(6, 8, 18, 28, SIGMA82[i * 16 + 14], SIGMA82[i * 16 + 15]);
    }

    for (i = 0; i < 16; i++) {
        ctx.h[i] = ctx.h[i] ^ v[i] ^ v[i + 16];
    }
}

// 64-bit unsigned addition
// Sets v[a,a+1] += v[b,b+1]
// v should be a Uint32Array
function ADD64AA(v: WordArray, a: number, b: number) {
    let o0 = v[a] + v[b],
        o1 = v[a + 1] + v[b + 1];

    if (o0 >= 0x100000000) o1++;

    v[a] = o0;
    v[a + 1] = o1;
}

// 64-bit unsigned addition
// Sets v[a,a+1] += b
// b0 is the low 32 bits of b, b1 represents the high 32 bits
function ADD64AC(v: WordArray, a: number, b0: number, b1: number) {
    let o0 = v[a] + b0;

    if (b0 < 0) o0 += 0x100000000;

    let o1 = v[a + 1] + b1;

    if (o0 >= 0x100000000) o1++;

    v[a] = o0;
    v[a + 1] = o1;
}

// Little-endian byte access
function B2B_GET32(arr: WordArray, i: number): number {
    return arr[i] ^ (arr[i + 1] << 8) ^ (arr[i + 2] << 16) ^ (arr[i + 3] << 24);
}

// G Mixing function
// The ROTRs are inlined for speed
function B2B_G(a: number, b: number, c: number, d: number, ix: number, iy: number) {
    const x0 = m[ix];
    const x1 = m[ix + 1];
    const y0 = m[iy];
    const y1 = m[iy + 1];

    ADD64AA(v, a, b); // v[a,a+1] += v[b,b+1] ... in JS we must store a uint64 as two uint32s
    ADD64AC(v, a, x0, x1); // v[a, a+1] += x ... x0 is the low 32 bits of x, x1 is the high 32 bits

    // v[d,d+1] = (v[d,d+1] xor v[a,a+1]) rotated to the right by 32 bits
    let xor0 = v[d] ^ v[a];
    let xor1 = v[d + 1] ^ v[a + 1];
    v[d] = xor1;
    v[d + 1] = xor0;

    ADD64AA(v, c, d);

    // v[b,b+1] = (v[b,b+1] xor v[c,c+1]) rotated right by 24 bits
    xor0 = v[b] ^ v[c];
    xor1 = v[b + 1] ^ v[c + 1];
    v[b] = (xor0 >>> 24) ^ (xor1 << 8);
    v[b + 1] = (xor1 >>> 24) ^ (xor0 << 8);

    ADD64AA(v, a, b);
    ADD64AC(v, a, y0, y1);

    // v[d,d+1] = (v[d,d+1] xor v[a,a+1]) rotated right by 16 bits
    xor0 = v[d] ^ v[a];
    xor1 = v[d + 1] ^ v[a + 1];
    v[d] = (xor0 >>> 16) ^ (xor1 << 16);
    v[d + 1] = (xor1 >>> 16) ^ (xor0 << 16);

    ADD64AA(v, c, d);

    // v[b,b+1] = (v[b,b+1] xor v[c,c+1]) rotated right by 63 bits
    xor0 = v[b] ^ v[c];
    xor1 = v[b + 1] ^ v[c + 1];
    v[b] = (xor1 >>> 31) ^ (xor0 << 1);
    v[b + 1] = (xor0 >>> 31) ^ (xor1 << 1);
}