import type { BankTerm } from '../api';

/**
 * Whether a term matched the query. One predicate for the bank and for the jump palette: were they
 * to diverge, the palette would find what the bank it leads to does not show.
 *
 * Case is folded on both sides: hanzi have none, but the source side of a pair is sometimes Latin,
 * and a one-sided filter would behave differently in the two columns.
 */
export const matchesTerm = (query: string) => {
  // The query is normalized ONCE, not per term: the predicate is called over a thousand rows per
  // repaint, and a `trim().toLowerCase()` inside would cost a thousand needless strings.
  const needle = query.trim().toLowerCase();
  // ⚠ There is no search through the description here and there cannot be: the description is
  // covered by the spoiler, and a field that is searched through works as an oracle — the covered
  // text is computed through it while revealing nothing.
  return (term: BankTerm) =>
    needle === '' ||
    term.src.toLowerCase().includes(needle) ||
    term.dst.toLowerCase().includes(needle);
};