// Search for the stack picker: every typed word must start a word in a note's title or tags.
import { byTitle } from './stack.mjs';

/** Lowercase words without accents; periods and apostrophes join, so "A.I." is "ai". @type {(text: string) => string[]} */
const words = (text) => text
  .normalize('NFD').replace(/\p{M}/gu, '')
  .toLowerCase()
  .replace(/[.'’]/g, '')
  .split(/[^\p{L}\p{N}]+/u)
  .filter(Boolean);

/** Whether some word in `list` starts with `w`. @type {(list: string[], w: string) => boolean} */
const starts = (list, w) => list.some((t) => t.startsWith(w));

/**
 * How `entry` matches the query words: `null`, `{ title: true, leads }`, or `{ tag }` for a tag-only match.
 * @param {{ title: string, tags: string[] }} entry
 * @param {string[]} q
 */
function match(entry, q) {
  const title = words(entry.title);
  let tag;
  for (const w of q) {
    if (starts(title, w)) continue;
    const t = entry.tags.find((x) => starts(words(x), w));
    if (t == null) return null;
    tag ??= t;
  }
  if (tag != null) return { tag };
  // match-sorter's tiers: a title that starts with the whole query beats one with matching words.
  return { title: true, leads: title.join(' ').startsWith(q.join(' ')) };
}

/**
 * Notes matching `query`, as `[{ entry, tag? }]` in display order: titles that start with the
 * query, other title matches, then notes where some word only matched a tag (that tag is `tag`),
 * each alphabetical. An empty query lists every note.
 * @template {{ title: string, tags: string[] }} T
 * @param {T[]} entries
 * @param {string} query
 * @returns {{ entry: T, tag?: string }[]}
 */
export function searchNotes(entries, query) {
  const q = words(query);
  /** @type {{ entry: T, tag?: string }[][]} */
  const tiers = [[], [], []];
  for (const entry of [...entries].sort(byTitle)) {
    const m = match(entry, q);
    if (!m) continue;
    if (m.title) tiers[m.leads ? 0 : 1].push({ entry });
    else tiers[2].push({ entry, tag: m.tag });
  }
  return tiers.flat();
}