// 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 } = require('./presence');

function register(userId, ws) {
  if (!chatClients.has(userId)) chatClients.set(userId, new Set());
  chatClients.get(userId).add(ws);
  ws._chatUserId = userId;
}

function unregister(ws) {
  const id = ws && ws._chatUserId;
  if (!id) return;
  const set = chatClients.get(id);
  if (set) { set.delete(ws); if (!set.size) chatClients.delete(id); }
}

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 (_) {} } }
}

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