// Notes and lists: notes and checklists that are private, shared with the whole family, or shared with chosen people. Anyone a note is shared with can edit it;
// checklist items are changed one at a time (tick, add, edit, remove), so two people ticking things at once never overwrite each other. Kept in DATA_DIR/notes.json.
const fs = require('fs'), path = require('path'), crypto = require('crypto');
const atomicWrite = require('./atomic');
const users = require('./users');
const { readBody } = require('./body');

const DATA_DIR = process.env.DATA_DIR || path.join(__dirname, 'data'), FILE = () => path.join(DATA_DIR, 'notes.json');
const COLORS = ['', 'red', 'orange', 'yellow', 'green', 'teal', 'blue', 'purple', 'pink'];
const MAX_NOTES = 3000, MAX_ITEMS = 300, MAX_BODY = 50000;
const json = (res, code, o) => { res.writeHead(code, { 'content-type': 'application/json', 'cache-control': 'no-store' }); res.end(JSON.stringify(o)); };
const fail = (code, message, extra) => Object.assign(new Error(message), { code, extra });
const str = (v, n) => String(v == null ? '' : v).replace(/[\u0000-\u0008\u000b\u000c\u000e-\u001f]/g, '').slice(0, n);
const newId = () => crypto.randomBytes(6).toString('hex');
let cache = null;
const all = () => cache || (cache = (() => { try { const j = JSON.parse(fs.readFileSync(FILE(), 'utf8')); return Array.isArray(j.notes) ? j.notes : []; } catch { return []; } })());
const save = () => { fs.mkdirSync(path.dirname(FILE()), { recursive: true }); atomicWrite(FILE(), JSON.stringify({ notes: all() }), { mode: 0o600 }); };

const live = uid => { const u = users.get(uid); return !!u && !u.disabled && users.can(u, 'notes'); };
const sees = (n, me) => n.owner === me.id || (n.share === 'family' && users.can(me, 'notes')) || (Array.isArray(n.share) && n.share.includes(me.id));
const nameOf = uid => { const u = users.get(uid); return u ? u.name : 'Someone'; };
const view = (n, me) => ({ id: n.id, type: n.type, title: n.title, body: n.body, items: n.items, owner: n.owner, ownerName: nameOf(n.owner), mine: n.owner === me.id, share: n.share, sharedWith: Array.isArray(n.share) ? n.share.map(id => ({ id, name: nameOf(id) })) : [], color: n.color, pinned: n.pinned, archived: n.archived, created: n.created, updated: n.updated, updatedByName: n.updatedBy ? nameOf(n.updatedBy) : '', rev: n.rev });
const cleanShare = (v, me) => v === 'family' ? 'family' : Array.isArray(v) ? [...new Set(v.map(String))].filter(id => id !== me.id && live(id)).slice(0, 30) : 'me';
const touch = (n, me) => { n.updated = Date.now(); n.updatedBy = me.id; n.rev = (n.rev || 0) + 1; };
const find = (id, me, ownerOnly) => { const n = all().find(x => x.id === id); if (!n || !sees(n, me)) throw fail(404, 'Note not found'); if (ownerOnly && n.owner !== me.id && me.role !== 'admin') throw fail(403, 'Only the person who made it, or an admin, can do that'); return n; };

async function handle(req, res) {
  const u = new URL(req.url, 'http://x'), p = u.pathname.slice('/api/notes'.length) || '/', me = users.current();
  try {
    let m;
    if (p === '/' && req.method === 'GET') return json(res, 200, { notes: all().filter(n => sees(n, me)).sort((a, b) => (b.pinned - a.pinned) || b.updated - a.updated).map(n => view(n, me)), people: users.all().filter(x => x.id !== me.id && live(x.id)).map(x => ({ id: x.id, name: x.name })) });
    if (p === '/' && req.method === 'POST') { // create, or change the note's own fields
      const b = JSON.parse(await readBody(req, MAX_BODY + 5e4) || '{}');
      if (!b.id) {
        if (all().length >= MAX_NOTES) throw fail(400, 'That is plenty of notes');
        const type = b.type === 'list' ? 'list' : 'note', n = { id: newId(), type, title: str(b.title, 120).trim(), body: type === 'note' ? str(b.body, MAX_BODY) : '', items: type === 'list' ? (Array.isArray(b.items) ? b.items : []).map(t => str(t, 300).trim()).filter(Boolean).slice(0, MAX_ITEMS).map(text => ({ id: newId(), text, done: false })) : [], owner: me.id, share: cleanShare(b.share === undefined ? 'family' : b.share, me), color: COLORS.includes(b.color) ? b.color : '', pinned: false, archived: false, created: Date.now(), updated: Date.now(), updatedBy: me.id, rev: 1 };
        all().push(n); save(); return json(res, 200, view(n, me));
      }
      const n = find(String(b.id), me, b.share !== undefined);
      if (b.rev !== undefined && +b.rev !== n.rev && (b.title !== undefined || b.body !== undefined)) throw fail(409, 'Someone else changed this note while you were editing', { note: view(n, me) });
      if (b.title !== undefined) n.title = str(b.title, 120).trim(); if (b.body !== undefined && n.type === 'note') n.body = str(b.body, MAX_BODY);
      if (b.share !== undefined) n.share = cleanShare(b.share, me); if (b.color !== undefined && COLORS.includes(b.color)) n.color = b.color;
      if (b.pinned !== undefined) n.pinned = !!b.pinned; if (b.archived !== undefined) n.archived = !!b.archived;
      touch(n, me); save(); return json(res, 200, view(n, me));
    }
    if ((m = /^\/([0-9a-f]{12})$/.exec(p)) && req.method === 'DELETE') { const n = find(m[1], me, true); cache = all().filter(x => x !== n); save(); return json(res, 200, { ok: true }); }
    if ((m = /^\/([0-9a-f]{12})\/items$/.exec(p)) && req.method === 'POST') { // one change to a checklist
      const n = find(m[1], me); if (n.type !== 'list') throw fail(400, 'That is not a checklist'); const b = JSON.parse(await readBody(req, 2e4) || '{}'), it = id => n.items.find(x => x.id === String(id));
      if (b.text !== undefined && !b.edit) { const t = str(b.text, 300).trim(); if (!t) throw fail(400, 'Write the item'); if (n.items.length >= MAX_ITEMS) throw fail(400, 'That is a long list'); n.items.push({ id: newId(), text: t, done: false, addedBy: me.name }); }
      else if (b.toggle) { const x = it(b.toggle); if (!x) throw fail(404, 'Item not found'); x.done = !!b.done; if (x.done) { x.by = me.id; x.byName = me.name; x.at = Date.now(); } else { delete x.by; delete x.byName; delete x.at; } }
      else if (b.edit) { const x = it(b.edit), t = str(b.text, 300).trim(); if (!x || !t) throw fail(400, 'Write the item'); x.text = t; }
      else if (b.remove) n.items = n.items.filter(x => x.id !== String(b.remove));
      else if (b.clearDone) n.items = n.items.filter(x => !x.done);
      else throw fail(400, 'Nothing to do');
      touch(n, me); save(); return json(res, 200, view(n, me));
    }
    return json(res, 404, { error: 'Not found' });
  } catch (e) { return json(res, e.code >= 400 && e.code < 600 ? e.code : e.status === 413 ? 413 : 400, { error: e instanceof SyntaxError ? 'Bad request' : e.message, ...(e.extra || {}) }); }
}

/** Notes and lists this person can see that mention the words: [{ id, type, title, snippet, share }]. */
function search(me, q) {
  const needle = q.toLowerCase(), out = [];
  for (const n of all()) { if (!sees(n, me) || n.archived) continue; const text = n.type === 'list' ? n.items.map(i => i.text).join(' · ') : n.body, hay = (n.title + ' ' + text).toLowerCase(); if (!hay.includes(needle)) continue;
    const at = text.toLowerCase().indexOf(needle); out.push({ id: n.id, type: n.type, title: n.title || (n.type === 'list' ? 'Checklist' : 'Note'), snippet: (at > 20 ? '…' : '') + text.slice(Math.max(0, at - 20), Math.max(0, at - 20) + 90), share: n.share === 'family' ? 'Family' : n.share === 'me' ? 'Just me' : 'Shared' }); }
  return out.slice(0, 8);
}
/** Notes and lists shared with the whole family, for the family board. */
const familyNotes = () => all().filter(n => n.share === 'family' && !n.archived).sort((a, b) => (b.pinned - a.pinned) || b.updated - a.updated).slice(0, 20).map(n => ({ id: n.id, type: n.type, title: n.title || (n.type === 'list' ? 'Checklist' : 'Note'), pinned: n.pinned, total: n.items.length, done: n.items.filter(i => i.done).length, next: (n.items.find(i => !i.done) || {}).text || '', items: n.type === 'list' ? n.items.slice(0, 80).map(i => ({ text: i.text, done: !!i.done, by: i.addedBy || '' })) : [], body: n.type === 'note' ? n.body.slice(0, 400) : '' }));
module.exports = { handle, search, familyNotes };