/** F6 — Crypto monomers: MC_48–MC_55 (Web Crypto API) */

export const hashSha256 = async (data: string | Uint8Array): Promise<Uint8Array> => {
  const buf = typeof data === 'string' ? new TextEncoder().encode(data) : data;
  const ab = new ArrayBuffer(buf.byteLength);
  new Uint8Array(ab).set(buf);
  return new Uint8Array(await crypto.subtle.digest('SHA-256', ab));
};

export const hashHex = async (data: string | Uint8Array): Promise<string> =>
  Array.from(await hashSha256(data)).map(b => b.toString(16).padStart(2, '0')).join('');

export const xorBytes = (a: Uint8Array, b: Uint8Array): Uint8Array => {
  const out = new Uint8Array(Math.min(a.length, b.length));
  for (let i = 0; i < out.length; i++) out[i] = (a[i] ?? 0) ^ (b[i] ?? 0);
  return out;
};
export const rotateLeft = (v: number, n: number): number => {
  const s = ((n % 32) + 32) % 32;
  return ((v << s) | (v >>> (32 - s))) >>> 0;
};
export const rotateRight = (v: number, n: number): number => {
  const s = ((n % 32) + 32) % 32;
  return ((v >>> s) | (v << (32 - s))) >>> 0;
};
export const constantEq = (a: Uint8Array, b: Uint8Array): boolean => {
  if (a.length !== b.length) return false;
  let d = 0;
  for (let i = 0; i < a.length; i++) d |= (a[i] ?? 0) ^ (b[i] ?? 0);
  return d === 0;
};
export const zeroBytes = (n: number): Uint8Array => new Uint8Array(Math.min(n, 4096));
export const bytesToHex = (data: Uint8Array): string =>
  Array.from(data).map(b => b.toString(16).padStart(2, '0')).join('');