// Replicates the PHP search.php title normalization:
//   - replace ligatures and superscripts
//   - strip everything that is not Latin or 0-9
//   - lowercase

const TITLE_SEARCHES = ['œ', 'Œ', 'æ', 'Æ', 'é', 'è', '²', '³', '⁴'];
const TITLE_REPLACES = ['oe', 'Oe', 'ae', 'Ae', 'é', 'è', '2', '3', '4'];

const FILTER_RE = /[^\p{Script=Latin}0-9]+/gu;

export function translit(s) {
  if (!s) return '';
  let out = s;
  for (let i = 0; i < TITLE_SEARCHES.length; i++) {
    out = out.split(TITLE_SEARCHES[i]).join(TITLE_REPLACES[i]);
  }
  return out;
}

export function filterTitle(s) {
  if (!s) return '';
  return translit(s).replace(FILTER_RE, '');
}

export function filterAndLower(s) {
  return filterTitle(s).toLocaleLowerCase();
}

export { FILTER_RE };