'use strict';
// Checklist items (`- [ ] text`) across the notes, and ticking one from outside its page.
// A task is identified by its page and line number in the page's body (what vault.read returns), plus its text,
// so a file that changed since the list was made is never edited blindly.

const TASK = /^(\s*(?:>\s*)*[-*+]\s+)\[([ xX])\](\s+)(.*)$/;
const DUE = /(?:📅|\bdue:|\[due::)\s*(\d{4}-\d{2}-\d{2})/;
const TAG = /(?:^|\s)#([\p{L}\p{N}_/-]*[\p{L}_/-][\p{L}\p{N}_/-]*)/gu;

// Line indexes inside ``` / ~~~ fences are not tasks.
function* lines(body) {
  let fence = null;
  const all = String(body || '').split('\n');
  for (let i = 0; i < all.length; i++) {
    const f = all[i].match(/^\s*(```|~~~)/);
    if (f) { fence = fence === f[1] ? null : fence || f[1]; continue; }
    if (!fence) yield [i, all[i]];
  }
}

// [{ id, title, icon, line, done, text, due, tags, depth }] for every task on every page (boards and canvases excluded:
// a board's cards are its own thing).
function findTasks(pages) {
  const out = [];
  for (const p of pages) {
    if (!p.exists || p.kind === 'canvas' || /\.canvas$/i.test(p.id)) continue;
    if (p.props && p.props['kanban-plugin']) continue;
    for (const [line, text] of lines(p.body)) {
      const m = text.match(TASK);
      if (!m) continue;
      const body = m[4].trim();
      if (!body) continue;
      const tags = new Set((p.tags || []).map(String));
      for (const t of body.matchAll(TAG)) tags.add(t[1]);
      const due = body.match(DUE);
      out.push({
        id: p.id, title: p.title, icon: p.icon || null, line,
        done: m[2] !== ' ', text: body, due: due ? due[1] : '', tags: [...tags],
        depth: Math.floor((m[1].match(/^\s*/)[0].replace(/\t/g, '  ').length) / 2)
      });
    }
  }
  return out;
}

// The body with the task at `line` ticked or unticked; null if the line is no longer that task.
function setTask(body, line, text, done) {
  const all = String(body || '').split('\n');
  const m = all[line] && all[line].match(TASK);
  if (!m || m[4].trim() !== String(text).trim()) return null;
  all[line] = m[1] + (done ? '[x]' : '[ ]') + m[3] + m[4];
  return all.join('\n');
}

module.exports = { findTasks, setTask };