// Pure-JS SHA-1/SHA-256: the sync call sites (bucket routing, script shas,
// token digests) cannot await crypto.subtle, and node:crypto is off-limits
// in the platform-free core.

const encoder = new TextEncoder();

const toBytes = (data: string | Uint8Array): Uint8Array =>
  typeof data === "string" ? encoder.encode(data) : data;

const toHex = (words: number[]): string =>
  words.map((word) => (word >>> 0).toString(16).padStart(8, "0")).join("");

const padMessage = (bytes: Uint8Array): DataView => {
  const bitLength = bytes.length * 8;
  const padded = new Uint8Array((((bytes.length + 8) >> 6) + 1) << 6);
  padded.set(bytes);
  padded[bytes.length] = 0x80;
  const view = new DataView(padded.buffer);
  view.setUint32(padded.length - 8, Math.floor(bitLength / 0x100000000));
  view.setUint32(padded.length - 4, bitLength >>> 0);
  return view;
};

const K256 = [
  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 rotr = (value: number, bits: number): number =>
  (value >>> bits) | (value << (32 - bits));

const sha256Words = (data: string | Uint8Array): number[] => {
  const view = padMessage(toBytes(data));
  const h = [
    0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c,
    0x1f83d9ab, 0x5be0cd19,
  ];
  const w = new Array<number>(64);
  for (let offset = 0; offset < view.byteLength; offset += 64) {
    for (let i = 0; i < 16; i++) w[i] = view.getUint32(offset + i * 4);
    for (let i = 16; i < 64; i++) {
      const s0 =
        rotr(w[i - 15]!, 7) ^ rotr(w[i - 15]!, 18) ^ (w[i - 15]! >>> 3);
      const s1 = rotr(w[i - 2]!, 17) ^ rotr(w[i - 2]!, 19) ^ (w[i - 2]! >>> 10);
      w[i] = (w[i - 16]! + s0 + w[i - 7]! + s1) | 0;
    }
    let [a, b, c, d, e, f, g, hh] = h as [
      number,
      number,
      number,
      number,
      number,
      number,
      number,
      number,
    ];
    for (let i = 0; i < 64; i++) {
      const s1 = rotr(e, 6) ^ rotr(e, 11) ^ rotr(e, 25);
      const ch = (e & f) ^ (~e & g);
      const t1 = (hh + s1 + ch + K256[i]! + w[i]!) | 0;
      const s0 = rotr(a, 2) ^ rotr(a, 13) ^ rotr(a, 22);
      const maj = (a & b) ^ (a & c) ^ (b & c);
      const t2 = (s0 + maj) | 0;
      hh = g;
      g = f;
      f = e;
      e = (d + t1) | 0;
      d = c;
      c = b;
      b = a;
      a = (t1 + t2) | 0;
    }
    h[0] = (h[0]! + a) | 0;
    h[1] = (h[1]! + b) | 0;
    h[2] = (h[2]! + c) | 0;
    h[3] = (h[3]! + d) | 0;
    h[4] = (h[4]! + e) | 0;
    h[5] = (h[5]! + f) | 0;
    h[6] = (h[6]! + g) | 0;
    h[7] = (h[7]! + hh) | 0;
  }
  return h;
};

export const sha256Hex = (data: string | Uint8Array): string =>
  toHex(sha256Words(data));

export const sha256Bytes = (data: string | Uint8Array): Uint8Array => {
  const words = sha256Words(data);
  const bytes = new Uint8Array(32);
  const view = new DataView(bytes.buffer);
  words.forEach((word, i) => view.setUint32(i * 4, word));
  return bytes;
};

export const sha1Hex = (data: string | Uint8Array): string => {
  const view = padMessage(toBytes(data));
  const h = [0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476, 0xc3d2e1f0];
  const w = new Array<number>(80);
  for (let offset = 0; offset < view.byteLength; offset += 64) {
    for (let i = 0; i < 16; i++) w[i] = view.getUint32(offset + i * 4);
    for (let i = 16; i < 80; i++) {
      const value = w[i - 3]! ^ w[i - 8]! ^ w[i - 14]! ^ w[i - 16]!;
      w[i] = (value << 1) | (value >>> 31);
    }
    let [a, b, c, d, e] = h as [number, number, number, number, number];
    for (let i = 0; i < 80; i++) {
      const f =
        i < 20
          ? ((b & c) | (~b & d)) + 0x5a827999
          : i < 40
            ? (b ^ c ^ d) + 0x6ed9eba1
            : i < 60
              ? ((b & c) | (b & d) | (c & d)) + 0x8f1bbcdc
              : (b ^ c ^ d) + 0xca62c1d6;
      const next = (((a << 5) | (a >>> 27)) + f + e + w[i]!) | 0;
      e = d;
      d = c;
      c = (b << 30) | (b >>> 2);
      b = a;
      a = next;
    }
    h[0] = (h[0]! + a) | 0;
    h[1] = (h[1]! + b) | 0;
    h[2] = (h[2]! + c) | 0;
    h[3] = (h[3]! + d) | 0;
    h[4] = (h[4]! + e) | 0;
  }
  return toHex(h);
};

export const timingSafeEqualBytes = (a: Uint8Array, b: Uint8Array): boolean => {
  if (a.length !== b.length) return false;
  let diff = 0;
  for (let i = 0; i < a.length; i++) diff |= a[i]! ^ b[i]!;
  return diff === 0;
};

export const randomHex = (byteLength: number): string =>
  Array.from(crypto.getRandomValues(new Uint8Array(byteLength)), (byte) =>
    byte.toString(16).padStart(2, "0"),
  ).join("");