'use strict';

const { scrypt } = require ('scrypt-js');

/**
 * creates a scrypt hash
 *
 * @param {string} str string input
 * @param {string} salt salt#
 * @param {(progress: number) => void} [progress] progress callback
 * @returns {Promise<string>} hash
 */
async function pbkdf_scrypt (str, salt, progress) {
  const bstr = Buffer.from (str.normalize ('NFKC'), 'utf-8');
  const bsalt = Buffer.from (salt.normalize ('NFKC'), 'utf-8');
  const hash = await scrypt (bstr, bsalt, 8192, 8, 1, 64, progress);
  return Buffer.from (hash)
    .toString ('hex');
}

module.exports = { pbkdf_scrypt };