// Family Chat: a messenger built into the hub, for the people who have an account here. Direct chats and groups, text, attachments, replies, reactions, edit and delete,
// unread counts, search, mute and archive, live delivery (server-sent events) and phone push when someone is not looking. Everything is kept on this server, in
// DATA_DIR/chat: conversations and messages as JSON, attachments as files. (Messages are stored readable on the server; end-to-end encryption is a later decision.)
const fs = require('fs'), path = require('path'), crypto = require('crypto');
const { pipeline } = require('stream/promises');
const atomicWrite = require('./atomic');
const users = require('./users');
const inbox = require('./inbox');
const push = require('./push');
const cal = require('./cal'); // (its public-address check, for link previews)
const { readBody } = require('./body');

const DATA_DIR = process.env.DATA_DIR || path.join(__dirname, 'data'), ROOT = () => path.join(DATA_DIR, 'chat');
const MAX_TEXT = 8000, MAX_FILE = 100 * 1024 * 1024, MAX_FILES = 10, MAX_MEMBERS = 40, MAX_MSGS = 50000, PAGE = 60;
const EMOJI = /^[\p{Extended_Pictographic}‍️⃣\p{Emoji_Modifier}]{1,12}$/u;
const json = (res, code, o) => { res.writeHead(code, { 'content-type': 'application/json', 'cache-control': 'no-store' }); res.end(JSON.stringify(o)); };
const fail = (code, message) => Object.assign(new Error(message), { code });
const str = (v, n) => String(v == null ? '' : v).replace(/[\u0000-\u0008\u000b\u000c\u000e-\u001f]/g, '').slice(0, n);
const newId = () => crypto.randomBytes(8).toString('hex');
const idOk = s => /^[0-9a-f]{16}$/.test(s || '') || /^d:[0-9a-z]+:[0-9a-z]+$/.test(s || '');

// ---- storage (small enough to hold in memory and write whole)
const cvFile = () => path.join(ROOT(), 'convs.json'), msFile = id => path.join(ROOT(), 'msgs', id.replace(/:/g, '_') + '.json'), flFile = () => path.join(ROOT(), 'files.json'), blob = id => path.join(ROOT(), 'files', id);
const read = (f, d) => { try { return JSON.parse(fs.readFileSync(f, 'utf8')); } catch { return d; } };
const write = (f, v) => { fs.mkdirSync(path.dirname(f), { recursive: true, mode: 0o700 }); atomicWrite(f, JSON.stringify(v), { mode: 0o600 }); };
let convsC = null, filesC = null; const msgsC = new Map();
const convs = () => convsC || (convsC = read(cvFile(), []));
const saveConvs = () => write(cvFile(), convs());
const files = () => filesC || (filesC = read(flFile(), {}));
const saveFiles = () => write(flFile(), files());
const msgs = id => { let m = msgsC.get(id); if (!m) { m = read(msFile(id), []); msgsC.set(id, m); if (msgsC.size > 60) msgsC.delete(msgsC.keys().next().value); } return m; };
const saveMsgs = id => write(msFile(id), msgs(id));
// each person's own marks: how far they have read, and which chats they muted or archived
const stFile = uid => path.join(users.dirOf(uid), 'chat-state.json');
const stateOf = uid => { const s = read(stFile(uid), {}); return { read: s.read || {}, delivered: s.delivered || {}, muted: s.muted || [], archived: s.archived || [], quiet: s.quiet || { on: false, from: '21:00', to: '07:00' } }; };
const saveState = (uid, s) => write(stFile(uid), s);

/** Is it quiet time for this person now (in their own time zone, from their reminder settings)? Phone alerts wait; the app still shows messages. */
function quietNow(uid) {
  const q = stateOf(uid).quiet; if (!q.on) return false; let tz = 'UTC'; try { tz = JSON.parse(fs.readFileSync(path.join(users.dirOf(uid), 'push.json'), 'utf8')).tz || 'UTC'; } catch { /* the default */ }
  const hm = push.localNow(tz).hm; return q.from <= q.to ? hm >= q.from && hm < q.to : hm >= q.from || hm < q.to;
}
const nameOf = uid => { const u = users.get(uid); return u ? u.name : 'Someone'; };
const live = uid => { const u = users.get(uid); return !!u && !u.disabled && users.can(u, 'chat'); };
const people = () => users.all().filter(u => !u.disabled && users.can(u, 'chat')).map(u => ({ id: u.id, name: u.name }));
const convOf = (id, me) => { const c = convs().find(x => x.id === id); if (!c || !c.members.includes(me.id)) throw fail(404, 'Conversation not found'); return c; };
const unreadIn = (c, uid, st) => { const r = st.read[c.id] || 0; return msgs(c.id).filter(m => m.ts > r && m.from !== uid && !m.deleted && !m.sys).length; };
const totalUnread = uid => { const st = stateOf(uid); return convs().filter(c => c.members.includes(uid) && !st.muted.includes(c.id) && !st.archived.includes(c.id)).reduce((n, c) => n + unreadIn(c, uid, st), 0); };
const preview = m => m ? (m.deleted ? 'This message was deleted' : m.sys ? str(m.text, 120) : m.poll ? '📊 ' + m.poll.q : m.att && m.att[0] && m.att[0].voice && !m.text ? '🎤 Voice message' : m.text ? str(m.text, 120) : m.att && m.att.length ? '📎 ' + (m.att[0].name || 'Attachment') : '') : '';

// ---- live updates (server-sent events), one stream per open app
const annFile = () => path.join(ROOT(), 'announcement.json');
const lastSeen = new Map(); // user id -> when they last did anything (kept in memory)
const clients = new Map(); // user id -> Set of responses
const online = uid => (clients.get(uid) || new Set()).size > 0;
function emit(uids, ev, per) { for (const uid of uids) for (const res of clients.get(uid) || []) { try { res.write('data: ' + JSON.stringify(per ? per(uid, ev) : ev) + '\n\n'); } catch { /* closed */ } } }

const view = (c, uid, st) => { const last = msgs(c.id).slice(-1)[0], others = c.members.filter(x => x !== uid), o = c.type === 'direct' ? others[0] : null;
  return { ttl: c.ttl || 0, ...(o ? { presence: { online: online(o), seen: lastSeen.get(o) || 0 } } : {}), id: c.id, type: c.type, name: c.type === 'group' ? c.name : nameOf(others[0] || uid), members: c.members.map(x => ({ id: x, name: nameOf(x) })), by: c.by, created: c.created, ts: last ? last.ts : c.created, preview: last ? (last.sys ? '' : c.type === 'group' && last.from !== uid ? nameOf(last.from) + ': ' : last.from === uid ? 'You: ' : '') + preview(last) : '', unread: unreadIn(c, uid, st), muted: st.muted.includes(c.id), archived: st.archived.includes(c.id) }; };
/** sent, delivered or read: for what you sent, from what the others have read and received (everyone, in a group). */
const statusOf = (m, c, uid, sts) => { if (m.from !== uid || m.sys) return undefined; const o = c.members.filter(x => x !== uid); if (!o.length) return 'sent'; if (o.every(x => (sts[x].read[c.id] || 0) >= m.ts)) return 'read'; if (o.every(x => (sts[x].delivered[c.id] || 0) >= m.ts)) return 'delivered'; return 'sent'; };
const stsOf = c => Object.fromEntries(c.members.map(x => [x, stateOf(x)]));
const msgView = (m, uid, c, sts) => ({ id: m.id, ts: m.ts, from: m.from, name: m.sys ? '' : nameOf(m.from), out: m.from === uid, text: m.text, att: m.att, quote: m.quote, react: m.react, edited: m.edited, deleted: m.deleted, sys: m.sys, fwd: m.fwd, mentions: m.mentions, exp: m.exp, link: m.link, poll: m.poll ? { ...m.poll, votes: m.votes || {} } : undefined, ...(c && sts ? { status: statusOf(m, c, uid, sts) } : {}) });
/** Someone has received or read the chat up to now: the senders' ticks change. */
function markDelivered(uid, c, also) { const st = stateOf(uid), last = msgs(c.id).slice(-1)[0]; if (!last) return; let ch = false; if ((st.delivered[c.id] || 0) < last.ts) { st.delivered[c.id] = last.ts; ch = true; } if (also && (st.read[c.id] || 0) < last.ts) { st.read[c.id] = last.ts; ch = true; } if (ch) { saveState(uid, st); emit(c.members.filter(x => x !== uid), { t: 'receipt', conv: c.id }); } }
const TTLS = [0, 3600, 86400, 604800], ttlWords = s => s === 3600 ? '1 hour' : s === 86400 ? '1 day' : s === 604800 ? '1 week' : 'off';
/** Disappearing messages that are due go, with their files. */
function purge() {
  const now = Date.now(); let filesChanged = false;
  for (const c of convs()) { const list = msgs(c.id), due = list.filter(m => m.exp && m.exp <= now); if (!due.length) continue;
    for (const m of due) for (const a of m.att || []) { fs.rm(blob(a.id), { force: true }, () => {}); delete files()[a.id]; filesChanged = true; }
    const keep = list.filter(m => !(m.exp && m.exp <= now)); list.length = 0; list.push(...keep); c.pins = (c.pins || []).filter(id => keep.some(m => m.id === id)); saveMsgs(c.id); saveConvs(); emit(c.members, { t: 'upd', conv: c.id }); }
  if (filesChanged) saveFiles();
}
setInterval(() => { try { purge(); } catch (e) { console.warn('[chat]', e.message); } }, 60e3).unref();
const mentionsIn = (text, c) => c.type !== 'group' ? [] : c.members.filter(uid => { const n = nameOf(uid); return n && new RegExp('(^|\\s)@' + n.replace(/[.*+?^${}()|[\]\\]/g, '\\$&') + '(?![\\w])', 'i').test(text); });

function send(me, b) {
  const c = convOf(String(b.conv || ''), me), text = str(b.text, MAX_TEXT).trim(), ids = (Array.isArray(b.files) ? b.files : []).map(String).slice(0, MAX_FILES), att = [];
  for (const id of ids) { const f = files()[id]; if (!f || f.conv !== c.id || f.by !== me.id || f.attached) throw fail(400, 'An attachment is not available (upload it again)'); att.push({ id, name: f.name, type: f.type, size: f.size, ...(f.voice ? { voice: true, wave: f.wave, dur: f.dur } : {}) }); }
  if (!text && !att.length) throw fail(400, 'Write something or attach a file');
  let quote; if (b.quote) { const q = msgs(c.id).find(x => x.id === String(b.quote)); if (q) quote = { id: q.id, from: q.from, name: nameOf(q.from), text: q.deleted ? '' : str(q.text || (q.att && q.att[0] ? q.att[0].name : ''), 200) }; }
  return addMsg(me, c, { text, att, quote });
}
/** Put a message in a chat and tell everyone: the live stream, and a phone notification for those who are away. */
function addMsg(me, c, { text, att = [], quote, fwd, sys, poll }) {
  const list = msgs(c.id), last = list[list.length - 1], ts = Math.max(Date.now(), last ? last.ts + 1 : 0), m = { id: newId(), ts, from: sys ? null : me.id, text, att: att.length ? att : undefined, quote, fwd, sys: sys || undefined, poll, react: {}, mentions: sys ? undefined : (mentionsIn(text, c).length ? mentionsIn(text, c) : undefined), exp: c.ttl && !sys ? ts + c.ttl * 1000 : undefined };
  list.push(m); if (list.length > MAX_MSGS) list.splice(0, list.length - MAX_MSGS); att.forEach(a => { if (files()[a.id]) files()[a.id].attached = true; }); saveMsgs(c.id); if (att.length) saveFiles();
  const body = sys ? text : (c.type === 'group' ? me.name + ': ' : '') + (poll ? '📊 ' + poll.q : text ? str(text, 140) : att[0] && att[0].voice ? '🎤 Voice message' : '📎 ' + att[0].name), title = c.type === 'group' ? c.name : me.name;
  emit(c.members, { t: 'msg', conv: c.id, id: m.id }, uid => ({ t: 'msg', conv: c.id, id: m.id, out: uid === me.id, sys: !!sys, mention: !!(m.mentions && m.mentions.includes(uid)), name: title, preview: body, unread: totalUnread(uid) }));
  for (const uid of c.members) if (online(uid) && (sys || uid !== me.id)) markDelivered(uid, c); // (what an open app has received counts as delivered)
  if (!sys) for (const uid of c.members) if (uid !== me.id && live(uid) && (!stateOf(uid).muted.includes(c.id) || (m.mentions && m.mentions.includes(uid)))) inbox.add(uid, { kind: 'chat', title, body: (m.mentions && m.mentions.includes(uid) ? '@ ' : '') + body, url: '#/chat/' + encodeURIComponent(c.id), tag: 'chat:' + c.id });
  if (!sys) for (const uid of c.members) if (uid !== me.id && !online(uid) && live(uid) && (!stateOf(uid).muted.includes(c.id) || (m.mentions && m.mentions.includes(uid))) && !quietNow(uid)) push.notify(uid, { title, body: (m.mentions && m.mentions.includes(uid) ? '@ ' : '') + body, url: '#/chat/' + encodeURIComponent(c.id), tag: 'chat:' + c.id }).catch(() => {});
  if (!sys) { const url = /https:\/\/[^\s<>"']+/.exec(text || ''); if (url) previewOf(url[0].replace(/[.,;:!?)\]]+$/, '')).then(p => { if (p && msgs(c.id).includes(m) && !m.deleted) { m.link = p; saveMsgs(c.id); emit(c.members, { t: 'upd', conv: c.id, id: m.id }); } }).catch(() => {}); }
  return msgView(m, me.id, c, stsOf(c));
}

// ---- link previews: the server reads the page's own title, description and picture (public https addresses only), so nobody's device contacts the site
const metaOf = (html, names) => { for (const n of names) { const m = new RegExp('<meta[^>]+(?:property|name)=["\']' + n + '["\'][^>]*>', 'i').exec(html), c = m && /content=["']([^"']*)["']/i.exec(m[0]) || (m && /content=([^\s>]+)/i.exec(m[0])); if (c && c[1].trim()) return c[1]; } return ''; };
const unent = t => String(t).replace(/&(#x[0-9a-f]+|#\d+|amp|lt|gt|quot|apos|#39);/gi, (x, e) => ({ amp: '&', lt: '<', gt: '>', quot: '"', apos: "'", '#39': "'" }[e.toLowerCase()] || (e[1] === 'x' || e[1] === 'X' ? String.fromCodePoint(parseInt(e.slice(2), 16)) : e[0] === '#' ? String.fromCodePoint(+e.slice(1)) : x))).replace(/\s+/g, ' ').trim();
/** The preview a page describes about itself: { url, site, title, desc, image } or null. */
function parsePreview(html, base) {
  const title = unent(metaOf(html, ['og:title', 'twitter:title']) || (/<title[^>]*>([\s\S]*?)<\/title>/i.exec(html) || [])[1] || ''), desc = unent(metaOf(html, ['og:description', 'twitter:description', 'description'])), site = unent(metaOf(html, ['og:site_name']));
  let image = metaOf(html, ['og:image', 'og:image:url', 'twitter:image']); try { image = image ? new URL(unent(image), base).href : ''; if (!/^https:/.test(image)) image = ''; } catch { image = ''; }
  if (!title && !desc) return null; return { url: base, site: site.slice(0, 80), title: title.slice(0, 200), desc: desc.slice(0, 300), image: image.slice(0, 500) };
}
const previews = new Map();
async function previewOf(raw) {
  const hit = previews.get(raw); if (hit && Date.now() - hit.t < 3600e3) return hit.p;
  let url; try { url = new URL(raw); } catch { return null; } let r;
  for (let hop = 0; hop < 4; hop++) { await cal.assertPublic(url); r = await fetch(url, { headers: { 'user-agent': 'Mozilla/5.0 (compatible; NE-Hub/1.0; link preview)', accept: 'text/html' }, redirect: 'manual', signal: AbortSignal.timeout(6000) }); if ([301, 302, 303, 307, 308].includes(r.status) && r.headers.get('location')) { url = new URL(r.headers.get('location'), url); try { await r.body?.cancel(); } catch {} continue; } break; }
  let p = null; if (r.ok && /html/i.test(r.headers.get('content-type') || '')) { const chunks = []; let n = 0; for await (const c of r.body) { n += c.length; chunks.push(c); if (n > 400000) break; } p = parsePreview(Buffer.concat(chunks).toString('utf8'), url.href); }
  previews.set(raw, { t: Date.now(), p }); if (previews.size > 200) previews.delete(previews.keys().next().value); return p;
}

async function handle(req, res) {
  const u = new URL(req.url, 'http://x'), p = (() => { try { return decodeURIComponent(u.pathname.slice('/api/chat'.length)) || '/'; } catch { return '/'; } })(), me = users.current(), q = u.searchParams; // (a chat id has colons, which a browser writes as %3A)
  try {
    let m; lastSeen.set(me.id, Date.now()); purge();
    if (p === '/status') return json(res, 200, { ok: true, me: { id: me.id, name: me.name }, unread: totalUnread(me.id) });
    if (p === '/people') return json(res, 200, people().filter(x => x.id !== me.id));
    if (p === '/events') {
      res.writeHead(200, { 'content-type': 'text/event-stream', 'cache-control': 'no-store', connection: 'keep-alive', 'x-accel-buffering': 'no' }); res.write(': hello\n\n');
      const set = clients.get(me.id) || new Set(); set.add(res); clients.set(me.id, set);
      const ka = setInterval(() => { try { res.write(': \n\n'); } catch { /* closed */ } }, 25000);
      res.on('close', () => { clearInterval(ka); set.delete(res); if (!set.size) clients.delete(me.id); lastSeen.set(me.id, Date.now()); }); return;
    }
    if (p === '/convs' && req.method === 'GET') { const st = stateOf(me.id); return json(res, 200, { convs: convs().filter(c => c.members.includes(me.id)).map(c => view(c, me.id, st)).sort((a, b) => b.ts - a.ts), unread: totalUnread(me.id) }); }
    if (p === '/new' && req.method === 'POST') {
      const b = JSON.parse(await readBody(req, 1e4) || '{}'); let c;
      if (b.type === 'group') {
        const name = str(b.name, 60).trim(); if (!name) throw fail(400, 'Give the group a name'); const mem = [...new Set([me.id, ...(Array.isArray(b.members) ? b.members : [])].map(String))].filter(live); if (mem.length < 2) throw fail(400, 'Add at least one other person'); if (mem.length > MAX_MEMBERS) throw fail(400, 'That is a lot of people for one group');
        c = { id: newId(), type: 'group', name, members: mem, by: me.id, created: Date.now() }; convs().push(c);
      } else {
        const other = String(b.with || ''); if (other === me.id || !live(other)) throw fail(400, 'Choose someone from the family'); const id = 'd:' + [me.id, other].sort().join(':'); c = convs().find(x => x.id === id);
        if (!c) { c = { id, type: 'direct', members: [me.id, other].sort(), by: me.id, created: Date.now() }; convs().push(c); }
      }
      saveConvs(); emit(c.members, { t: 'conv', conv: c.id }); return json(res, 200, { conv: view(c, me.id, stateOf(me.id)) });
    }
    if (p === '/conv/update' && req.method === 'POST') { // rename, add or remove people, leave (groups)
      const b = JSON.parse(await readBody(req, 1e4) || '{}'), c = convOf(String(b.id || ''), me); if (c.type !== 'group') throw fail(400, 'Only groups can be changed');
      const isOwner = c.by === me.id || me.role === 'admin'; const before = [...c.members];
      if (b.name !== undefined) { const n = str(b.name, 60).trim(); if (!n) throw fail(400, 'Give the group a name'); c.name = n; }
      for (const id of Array.isArray(b.add) ? b.add : []) if (live(String(id)) && !c.members.includes(String(id)) && c.members.length < MAX_MEMBERS) c.members.push(String(id));
      for (const id of Array.isArray(b.remove) ? b.remove : []) { if (!isOwner && String(id) !== me.id) throw fail(403, 'Only the person who made the group, or an admin, can remove others'); c.members = c.members.filter(x => x !== String(id)); }
      if (b.leave) c.members = c.members.filter(x => x !== me.id);
      if (!c.members.length) convsC = convs().filter(x => x !== c); else if (c.by && !c.members.includes(c.by)) c.by = c.members[0];
      saveConvs(); emit([...new Set([...before, ...c.members])], { t: 'conv', conv: c.id }); return json(res, 200, c.members.includes(me.id) ? { conv: view(c, me.id, stateOf(me.id)) } : { left: true });
    }
    if ((m = /^\/conv\/(\w[\w:]*)$/.exec(p)) && req.method === 'GET') {
      const c = convOf(m[1], me), all = msgs(c.id), before = +q.get('before') || Infinity, eligible = all.filter(x => x.ts < before), page = eligible.slice(-PAGE), sts = stsOf(c); markDelivered(me.id, c);
      return json(res, 200, { conv: view(c, me.id, stateOf(me.id)), pinned: (c.pins || []).map(id => all.find(x => x.id === id)).filter(x => x && !x.deleted).map(x => msgView(x, me.id, c, sts)), msgs: page.map(x => msgView(x, me.id, c, sts)), more: eligible.length > page.length, names: Object.fromEntries(c.members.map(x => [x, nameOf(x)])) });
    }
    if (p === '/send' && req.method === 'POST') return json(res, 200, { msg: send(me, JSON.parse(await readBody(req, 5e4) || '{}')) });
    if (p === '/upload' && req.method === 'POST') { // the body is the file; ?conv= says which chat it is for
      const c = convOf(String(q.get('conv') || ''), me); if ((+req.headers['content-length'] || 0) > MAX_FILE) throw fail(413, 'That file is too large (100 MB at most)');
      const id = newId(), type = /^[\w.+-]+\/[\w.+-]+$/.test(String(req.headers['content-type'] || '').split(';')[0].trim()) ? String(req.headers['content-type']).split(';')[0].trim().toLowerCase() : 'application/octet-stream', name = path.basename(str(q.get('name'), 160)).replace(/[\\/:*?"<>|]+/g, '_') || 'file';
      fs.mkdirSync(path.dirname(blob(id)), { recursive: true, mode: 0o700 }); let n = 0; req.on('data', d => { n += d.length; if (n > MAX_FILE) req.destroy(fail(413, 'That file is too large')); });
      try { await pipeline(req, fs.createWriteStream(blob(id) + '.part', { mode: 0o600 })); } catch (e) { fs.rm(blob(id) + '.part', { force: true }, () => {}); throw e.code === 413 ? e : fail(400, 'The upload did not finish'); }
      fs.renameSync(blob(id) + '.part', blob(id)); const voice = q.get('voice') === '1' && /^audio\//.test(type), wave = voice ? String(q.get('wave') || '').split(',').map(Number).filter(v => Number.isFinite(v)).slice(0, 64).map(v => Math.max(0, Math.min(100, Math.round(v)))) : undefined, dur = voice ? Math.max(0, Math.min(900, Math.round(+q.get('dur') || 0))) : undefined;
      files()[id] = { conv: c.id, by: me.id, name, type, size: n, ts: Date.now(), ...(voice ? { voice: true, wave, dur } : {}) }; saveFiles(); return json(res, 200, { id, name, type, size: n, voice: voice || undefined });
    }
    if ((m = /^\/file\/([0-9a-f]{16})$/.exec(p)) && req.method === 'GET') {
      const f = files()[m[1]]; if (!f) throw fail(404, 'Not found'); convOf(f.conv, me); let st; try { st = fs.statSync(blob(m[1])); } catch { throw fail(404, 'Not found'); }
      const inline = /^(image\/(png|jpeg|gif|webp|heic|heif|avif)|audio\/|video\/|application\/pdf$)/.test(f.type), h = { 'content-type': inline ? f.type : 'application/octet-stream', 'x-content-type-options': 'nosniff', 'cache-control': 'private, max-age=3600', 'accept-ranges': 'bytes', 'content-security-policy': "default-src 'none'; sandbox" };
      if (!inline || q.get('dl') === '1') h['content-disposition'] = `attachment; filename="${f.name.replace(/[^\x20-\x7e]/g, '_').replace(/"/g, '')}"; filename*=UTF-8''${encodeURIComponent(f.name)}`;
      const rg = /^bytes=(\d*)-(\d*)$/.exec(req.headers.range || '');
      if (rg && (rg[1] || rg[2])) { const a = rg[1] ? +rg[1] : Math.max(0, st.size - +rg[2]), b = rg[1] && rg[2] ? Math.min(+rg[2], st.size - 1) : st.size - 1; if (a > b || a >= st.size) { res.writeHead(416, { 'content-range': 'bytes */' + st.size }); return res.end(); } res.writeHead(206, { ...h, 'content-range': `bytes ${a}-${b}/${st.size}`, 'content-length': b - a + 1 }); return fs.createReadStream(blob(m[1]), { start: a, end: b }).pipe(res); }
      res.writeHead(200, { ...h, 'content-length': st.size }); return fs.createReadStream(blob(m[1])).pipe(res);
    }
    if (p === '/react' && req.method === 'POST') {
      const b = JSON.parse(await readBody(req, 1e4) || '{}'), c = convOf(String(b.conv || ''), me), x = msgs(c.id).find(y => y.id === String(b.msg)); if (!x || x.deleted) throw fail(404, 'Message not found');
      const e = String(b.emoji || ''); if (e && !EMOJI.test(e)) throw fail(400, 'That is not an emoji'); x.react = x.react || {}; if (e) x.react[me.id] = e; else delete x.react[me.id]; saveMsgs(c.id);
      emit(c.members, { t: 'upd', conv: c.id, id: x.id }); return json(res, 200, { ok: true });
    }
    if ((p === '/edit' || p === '/delete') && req.method === 'POST') {
      const b = JSON.parse(await readBody(req, 2e4) || '{}'), c = convOf(String(b.conv || ''), me), x = msgs(c.id).find(y => y.id === String(b.msg)); if (!x) throw fail(404, 'Message not found'); if (x.from !== me.id) throw fail(403, 'You can only change your own messages'); if (x.deleted) throw fail(400, 'That message was deleted');
      if (p === '/edit') { const t = str(b.text, MAX_TEXT).trim(); if (!t) throw fail(400, 'Write something'); if (Date.now() - x.ts > 48 * 3600e3) throw fail(400, 'Messages can be edited for two days'); x.text = t; x.edited = true; }
      else { x.deleted = true; x.text = ''; for (const a of x.att || []) { fs.rm(blob(a.id), { force: true }, () => {}); delete files()[a.id]; } x.att = undefined; x.react = {}; saveFiles(); }
      saveMsgs(c.id); emit(c.members, { t: 'upd', conv: c.id, id: x.id }); return json(res, 200, { ok: true });
    }
    if (p === '/read' && req.method === 'POST') { const b = JSON.parse(await readBody(req, 1e4) || '{}'), c = convOf(String(b.id || ''), me), st = stateOf(me.id), last = msgs(c.id).slice(-1)[0]; st.read[c.id] = last ? last.ts : Date.now(); st.delivered[c.id] = Math.max(st.delivered[c.id] || 0, st.read[c.id]); saveState(me.id, st); emit([me.id], { t: 'read', conv: c.id, unread: totalUnread(me.id) }); emit(c.members.filter(x => x !== me.id), { t: 'receipt', conv: c.id }); return json(res, 200, { ok: true, unread: totalUnread(me.id) }); }
    if ((p === '/conv/mute' || p === '/conv/archive') && req.method === 'POST') { const b = JSON.parse(await readBody(req, 1e4) || '{}'), c = convOf(String(b.id || ''), me), st = stateOf(me.id), k = p.endsWith('mute') ? 'muted' : 'archived'; st[k] = st[k].filter(x => x !== c.id); if (b.on) st[k].push(c.id); saveState(me.id, st); emit([me.id], { t: 'conv', conv: c.id, unread: totalUnread(me.id) }); return json(res, 200, { ok: true }); }
    if (p === '/announcement' && req.method === 'GET') return json(res, 200, read(annFile(), null));
    if (p === '/announcement' && req.method === 'POST') { // the family board on Home: an admin posts or clears it
      if (me.role !== 'admin') throw fail(403, 'Only an admin can change the announcement'); const b = JSON.parse(await readBody(req, 1e4) || '{}'), text = str(b.text, 300).trim();
      if (!text) { fs.rmSync(annFile(), { force: true }); emit(people().map(x => x.id), { t: 'announce' }); return json(res, 200, null); }
      const a = { id: newId(), text, by: me.name, at: Date.now() }; write(annFile(), a); for (const x of people()) if (x.id !== me.id) inbox.add(x.id, { kind: 'announce', title: 'Family announcement', body: text, url: '#/family' }); emit(people().map(x => x.id), { t: 'announce' }); return json(res, 200, a);
    }
    if (p === '/prefs' && req.method === 'GET') return json(res, 200, { quiet: stateOf(me.id).quiet });
    if (p === '/prefs' && req.method === 'POST') { const b = JSON.parse(await readBody(req, 1e4) || '{}'), st = stateOf(me.id), hm = /^([01]\d|2[0-3]):[0-5]\d$/; if (b.quiet) st.quiet = { on: !!b.quiet.on, from: hm.test(b.quiet.from) ? b.quiet.from : st.quiet.from, to: hm.test(b.quiet.to) ? b.quiet.to : st.quiet.to }; saveState(me.id, st); return json(res, 200, { quiet: st.quiet }); }
    if (p === '/poll' && req.method === 'POST') {
      const b = JSON.parse(await readBody(req, 1e4) || '{}'), c = convOf(String(b.conv || ''), me), q = str(b.question, 200).trim(), opts = (Array.isArray(b.options) ? b.options : []).map(o => str(o, 100).trim()).filter(Boolean).slice(0, 8);
      if (!q) throw fail(400, 'Ask a question'); if (opts.length < 2) throw fail(400, 'Give at least two choices');
      const msg = addMsg(me, c, { text: '', poll: { q, options: opts.map((t, i) => ({ id: String(i), text: t })), multi: !!b.multi } }); return json(res, 200, { msg });
    }
    if (p === '/vote' && req.method === 'POST') {
      const b = JSON.parse(await readBody(req, 1e4) || '{}'), c = convOf(String(b.conv || ''), me), x = msgs(c.id).find(y => y.id === String(b.msg)); if (!x || !x.poll || x.deleted) throw fail(404, 'Poll not found'); if (x.poll.closed) throw fail(400, 'This poll is closed');
      const ids = [...new Set((Array.isArray(b.opts) ? b.opts : []).map(String))].filter(id => x.poll.options.some(o => o.id === id)); if (!x.poll.multi) ids.splice(1);
      x.votes = x.votes || {}; if (ids.length) x.votes[me.id] = ids; else delete x.votes[me.id]; saveMsgs(c.id); emit(c.members, { t: 'upd', conv: c.id, id: x.id }); return json(res, 200, { ok: true });
    }
    if (p === '/poll/close' && req.method === 'POST') { const b = JSON.parse(await readBody(req, 1e4) || '{}'), c = convOf(String(b.conv || ''), me), x = msgs(c.id).find(y => y.id === String(b.msg)); if (!x || !x.poll) throw fail(404, 'Poll not found'); if (x.from !== me.id) throw fail(403, 'Only the person who asked can close it'); x.poll.closed = true; saveMsgs(c.id); emit(c.members, { t: 'upd', conv: c.id, id: x.id }); return json(res, 200, { ok: true }); }
    if (p === '/typing' && req.method === 'POST') { const c = convOf(String(JSON.parse(await readBody(req, 1e4) || '{}').conv || ''), me); emit(c.members.filter(x => x !== me.id), { t: 'typing', conv: c.id, from: me.id, name: me.name }); return json(res, 200, { ok: true }); }
    if (p === '/conv/ttl' && req.method === 'POST') { // disappearing messages: from now on, new messages go after this long
      const b = JSON.parse(await readBody(req, 1e4) || '{}'), c = convOf(String(b.id || ''), me), ttl = +b.ttl || 0; if (!TTLS.includes(ttl)) throw fail(400, 'Choose off, 1 hour, 1 day or 1 week');
      if ((c.ttl || 0) !== ttl) { c.ttl = ttl; saveConvs(); addMsg(me, c, { sys: true, text: ttl ? `${me.name} set messages to disappear after ${ttlWords(ttl)}` : `${me.name} turned off disappearing messages` }); }
      emit(c.members, { t: 'conv', conv: c.id }); return json(res, 200, { ok: true, ttl });
    }
    if (p === '/pin' && req.method === 'POST') {
      const b = JSON.parse(await readBody(req, 1e4) || '{}'), c = convOf(String(b.conv || ''), me), x = msgs(c.id).find(y => y.id === String(b.msg)); if (!x || x.deleted || x.sys) throw fail(404, 'Message not found');
      c.pins = (c.pins || []).filter(id => id !== x.id); if (b.on) { c.pins.push(x.id); if (c.pins.length > 5) c.pins.shift(); } saveConvs(); emit(c.members, { t: 'upd', conv: c.id, id: x.id }); return json(res, 200, { ok: true, pins: c.pins });
    }
    if (p === '/forward' && req.method === 'POST') { // a copy of a message (and its files) into another chat
      const b = JSON.parse(await readBody(req, 1e4) || '{}'), from = convOf(String(b.from || ''), me), to = convOf(String(b.to || ''), me), x = msgs(from.id).find(y => y.id === String(b.msg)); if (!x || x.deleted || x.sys) throw fail(404, 'Message not found');
      const att = (x.att || []).map(a => { const id = newId(); try { fs.copyFileSync(blob(a.id), blob(id)); } catch { return null; } files()[id] = { conv: to.id, by: me.id, name: a.name, type: a.type, size: a.size, ts: Date.now(), attached: true }; return { id, name: a.name, type: a.type, size: a.size, ...(a.voice ? { voice: true, wave: a.wave, dur: a.dur } : {}) }; }).filter(Boolean);
      if (att.length) saveFiles(); return json(res, 200, { msg: addMsg(me, to, { text: x.text || '', att, fwd: { name: nameOf(x.from) } }) });
    }
    if (p === '/search' && req.method === 'GET') {
      const needle = str(q.get('q'), 100).trim().toLowerCase(); if (needle.length < 2) return json(res, 200, { results: [] }); const out = [], st = stateOf(me.id);
      for (const c of convs().filter(x => x.members.includes(me.id))) { const cv = view(c, me.id, st); for (const x of msgs(c.id)) if (!x.deleted && !x.sys && x.text && x.text.toLowerCase().includes(needle)) out.push({ conv: c.id, convName: cv.name, msg: msgView(x, me.id) }); }
      return json(res, 200, { results: out.sort((a, b) => b.msg.ts - a.msg.ts).slice(0, 40) });
    }
    return json(res, 404, { error: 'Not found' });
  } catch (e) { if (res.headersSent) return res.destroy(); return json(res, e.code >= 400 && e.code < 600 ? e.code : e.status === 413 ? 413 : 400, { error: e instanceof SyntaxError ? 'Bad request' : e.message }); }
}

/** A child asks the parents (the admins) for something: a message in a direct chat with each of them. Returns how many were told. */
function askParents(me, text) {
  let n = 0;
  for (const a of users.all().filter(u => u.role === 'admin' && !u.disabled && u.id !== me.id)) {
    const id = 'd:' + [me.id, a.id].sort().join(':'); let c = convs().find(x => x.id === id); if (!c) { c = { id, type: 'direct', members: [me.id, a.id].sort(), by: me.id, created: Date.now() }; convs().push(c); saveConvs(); }
    addMsg(me, c, { text: str(text, 300) }); n++;
  }
  return n;
}
/** Messages in this person's chats that mention the words. */
function searchFor(me, q) {
  const needle = q.toLowerCase(), out = [], st = stateOf(me.id);
  for (const c of convs().filter(x => x.members.includes(me.id))) { const cv = view(c, me.id, st); for (const x of msgs(c.id)) if (!x.deleted && !x.sys && x.text && x.text.toLowerCase().includes(needle)) out.push({ conv: c.id, convName: cv.name, msg: msgView(x, me.id) }); }
  return out.sort((a, b) => b.msg.ts - a.msg.ts).slice(0, 8);
}
module.exports = { announcement: () => read(annFile(), null), handle, totalUnread, purge, parsePreview, askParents, searchFor };