/**
 * SHA-256 implementation fromhttps://github.com/6502/sha256/blob/main/sha256.js
 *
 * There are many SHA-256 implementations in various not-very-popular github
 * projects and gists.
 *
 * I'm not sure which one is the best; some might be more performant. But we can
 * optimize it later if necessary.
 *
 * The hash-based approach in SqProject is inspired by git architecture. Git
 * uses SHA-1, but SHA-1 is legacy, so we use SHA-256 instead.
 */

/*
Copyright 2022 Andrea Griffini

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

// sha256(data) returns the digest
// sha256() returns an object you can call .add(data) zero or more time and .digest() at the end
// digest is a 32-byte Uint8Array instance with an added .hex() function.
// Input should be either a string (that will be encoded as UTF-8) or an array-like object with values 0..255.
export function getHash(data: string) {
  let h0 = 0x6a09e667,
    h1 = 0xbb67ae85,
    h2 = 0x3c6ef372,
    h3 = 0xa54ff53a,
    h4 = 0x510e527f,
    h5 = 0x9b05688c,
    h6 = 0x1f83d9ab,
    h7 = 0x5be0cd19,
    tsz = 0,
    bp = 0;
  const k = [
    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
    0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
    0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
    0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
    0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
    0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
    0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
    0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
    0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
  ];
  const rrot = (x: any, n: any) => (x >>> n) | (x << (32 - n));
  const w = new Uint32Array(64);
  const buf = new Uint8Array(64);
  const process = () => {
    for (let j = 0, r = 0; j < 16; j++, r += 4) {
      w[j] =
        (buf[r] << 24) | (buf[r + 1] << 16) | (buf[r + 2] << 8) | buf[r + 3];
    }
    for (let j = 16; j < 64; j++) {
      const s0 = rrot(w[j - 15], 7) ^ rrot(w[j - 15], 18) ^ (w[j - 15] >>> 3);
      const s1 = rrot(w[j - 2], 17) ^ rrot(w[j - 2], 19) ^ (w[j - 2] >>> 10);
      w[j] = (w[j - 16] + s0 + w[j - 7] + s1) | 0;
    }
    let a = h0,
      b = h1,
      c = h2,
      d = h3,
      e = h4,
      f = h5,
      g = h6,
      h = h7;
    for (let j = 0; j < 64; j++) {
      const S1 = rrot(e, 6) ^ rrot(e, 11) ^ rrot(e, 25),
        ch = (e & f) ^ (~e & g),
        t1 = (h + S1 + ch + k[j] + w[j]) | 0,
        S0 = rrot(a, 2) ^ rrot(a, 13) ^ rrot(a, 22),
        maj = (a & b) ^ (a & c) ^ (b & c),
        t2 = (S0 + maj) | 0;
      h = g;
      g = f;
      f = e;
      e = (d + t1) | 0;
      d = c;
      c = b;
      b = a;
      a = (t1 + t2) | 0;
    }
    h0 = (h0 + a) | 0;
    h1 = (h1 + b) | 0;
    h2 = (h2 + c) | 0;
    h3 = (h3 + d) | 0;
    h4 = (h4 + e) | 0;
    h5 = (h5 + f) | 0;
    h6 = (h6 + g) | 0;
    h7 = (h7 + h) | 0;
    bp = 0;
  };
  const add = (data: any) => {
    data = new TextEncoder().encode(data);

    for (let i = 0; i < data.length; i++) {
      buf[bp++] = data[i];
      if (bp === 64) process();
    }
    tsz += data.length;
  };

  const digest = () => {
    buf[bp++] = 0x80;
    if (bp === 64) process();
    if (bp + 8 > 64) {
      while (bp < 64) buf[bp++] = 0x00;
      process();
    }
    while (bp < 58) buf[bp++] = 0x00;
    // Max number of bytes is 35,184,372,088,831
    const L = tsz * 8;
    buf[bp++] = (L / 1099511627776) & 255;
    buf[bp++] = (L / 4294967296) & 255;
    buf[bp++] = L >>> 24;
    buf[bp++] = (L >>> 16) & 255;
    buf[bp++] = (L >>> 8) & 255;
    buf[bp++] = L & 255;
    process();
    const reply = new Uint8Array(32);
    reply[0] = h0 >>> 24;
    reply[1] = (h0 >>> 16) & 255;
    reply[2] = (h0 >>> 8) & 255;
    reply[3] = h0 & 255;
    reply[4] = h1 >>> 24;
    reply[5] = (h1 >>> 16) & 255;
    reply[6] = (h1 >>> 8) & 255;
    reply[7] = h1 & 255;
    reply[8] = h2 >>> 24;
    reply[9] = (h2 >>> 16) & 255;
    reply[10] = (h2 >>> 8) & 255;
    reply[11] = h2 & 255;
    reply[12] = h3 >>> 24;
    reply[13] = (h3 >>> 16) & 255;
    reply[14] = (h3 >>> 8) & 255;
    reply[15] = h3 & 255;
    reply[16] = h4 >>> 24;
    reply[17] = (h4 >>> 16) & 255;
    reply[18] = (h4 >>> 8) & 255;
    reply[19] = h4 & 255;
    reply[20] = h5 >>> 24;
    reply[21] = (h5 >>> 16) & 255;
    reply[22] = (h5 >>> 8) & 255;
    reply[23] = h5 & 255;
    reply[24] = h6 >>> 24;
    reply[25] = (h6 >>> 16) & 255;
    reply[26] = (h6 >>> 8) & 255;
    reply[27] = h6 & 255;
    reply[28] = h7 >>> 24;
    reply[29] = (h7 >>> 16) & 255;
    reply[30] = (h7 >>> 8) & 255;
    reply[31] = h7 & 255;

    let res = "";
    reply.forEach((x: any) => (res += ("0" + x.toString(16)).slice(-2)));
    return res;
  };

  add(data);
  return digest();
}