import { SEPERATOR_CHARS } from '../../data/const.mjs';
import { MatcherBaseClass } from '../../types.mjs';

const separatorRegex = new RegExp(`[${SEPERATOR_CHARS.join('')}]`);
/*
 *-------------------------------------------------------------------------------
 * separators (any semi-repeated special character) -----------------------------
 *-------------------------------------------------------------------------------
 */
class MatchSeparator extends MatcherBaseClass {
  static getMostUsedSeparatorChar(password) {
    const mostUsedSeperators = [...password.split('').filter(c => separatorRegex.test(c)).reduce((memo, c) => {
      const m = memo.get(c);
      if (m) {
        memo.set(c, parseInt(m, 10) + 1);
      } else {
        memo.set(c, 1);
      }
      return memo;
    }, new Map()).entries()].sort(([_a, a], [_b, b]) => b - a);
    if (!mostUsedSeperators.length) return undefined;
    const match = mostUsedSeperators[0];
    // If the special character is only used once, don't treat it like a separator
    if (match[1] < 2) return undefined;
    return match[0];
  }
  static getSeparatorRegex(separator) {
    return new RegExp(`([^${separator}\n])(${separator})(?!${separator})`, 'g');
    // negative lookbehind can be added again in a few years when it is more supported by the browsers (currently 2023)
    // https://github.com/zxcvbn-ts/zxcvbn/issues/202
    // return new RegExp(`(?<!${separator})(${separator})(?!${separator})`, 'g')
  }
  match({
    password
  }) {
    const result = [];
    if (password.length === 0) return result;
    const mostUsedSpecial = MatchSeparator.getMostUsedSeparatorChar(password);
    if (mostUsedSpecial === undefined) return result;
    const isSeparator = MatchSeparator.getSeparatorRegex(mostUsedSpecial);
    for (const match of password.matchAll(isSeparator)) {
      if (match.index === undefined) continue;
      // add one to the index because we changed the regex from negative lookbehind to something simple.
      // this simple approach uses the first character before the separater too but we only need the index of the separater
      // https://github.com/zxcvbn-ts/zxcvbn/issues/202
      const i = match.index + 1;
      result.push({
        pattern: 'separator',
        token: mostUsedSpecial,
        i,
        j: i
      });
    }
    return result;
  }
}

export { MatchSeparator as default };
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