// Chat presence + real-time delivery. A logged-in user opens a WebSocket and sends
// `chat-hello`; signaling.js registers the socket here. Messages are persisted over HTTP
// (routes.js) and pushed live to the recipient's sockets via pushToUser().
const { chatClients, meetingRooms } = require('./presence');
let _repos = null; const repos = () => (_repos || (_repos = require('./repos'))); // lazy: avoid a require cycle

function register(userId, ws) {
  if (!chatClients.has(userId)) chatClients.set(userId, new Set());
  chatClients.get(userId).add(ws);
  ws._chatUserId = userId;
  try { repos().users.touchSeen(userId); } catch (_) {} // "last seen" (#2)
}

function unregister(ws) {
  const id = ws && ws._chatUserId;
  if (!id) return;
  const set = chatClients.get(id);
  if (set) {
    set.delete(ws);
    // Their LAST socket went away → stamp when they were last here, so contacts can show "last seen …".
    if (!set.size) { chatClients.delete(id); try { repos().users.touchSeen(id); } catch (_) {} }
  }
}

function isOnline(userId) {
  const s = chatClients.get(userId);
  return !!(s && s.size);
}

function pushToUser(userId, obj) {
  const s = chatClients.get(userId);
  if (!s) return;
  const data = JSON.stringify(obj);
  for (const ws of s) { if (ws.readyState === 1) { try { ws.send(data); } catch (_) {} } }
}

// --- Live presence -------------------------------------------------------------------------
// A user's effective status (online / in-a-call / away / …) changes with no HTTP round-trip:
// they connect or disconnect a socket, or join/leave a call. Without pushing that change, OTHER
// users only see it after a full page reload — impossible in the desktop/mobile apps. So whenever
// it changes we broadcast the user's fresh status to everyone else's sockets, and the client
// updates that contact's dot/subtitle in place.
function isInCall(userId) {
  for (const [, peers] of meetingRooms) { for (const [, p] of peers) { if (p.ws && p.ws._meetingUserId === userId) return true; } }
  return false;
}
function effectiveStatus(userId) {
  if (isInCall(userId)) return 'incall';           // derived (overrides the stored status)
  try { const u = repos().users.byId(userId); return (u && u.status) || 'active'; } catch (_) { return 'active'; }
}
function broadcastPresence(userId) {
  if (!userId) return;
  // Carry last_seen too, so a contact going offline immediately reads "Last seen just now" instead of a
  // bare "Offline" until the next sidebar reload (#2).
  let lastSeen = null;
  try { const u = repos().users.byId(userId); lastSeen = (u && u.last_seen) || null; } catch (_) {}
  const payload = JSON.stringify({ type: 'presence', userId, online: isOnline(userId), status: effectiveStatus(userId), lastSeen });
  for (const [uid, set] of chatClients) {
    if (uid === userId) continue;                  // no need to tell someone about their own status
    for (const ws of set) { if (ws.readyState === 1) { try { ws.send(payload); } catch (_) {} } }
  }
}

module.exports = { register, unregister, isOnline, pushToUser, broadcastPresence };