Update server.js

server.js

@@ -1,92 +1,100 @@
-// server.js — HF Spaces / Docker ready (PORT + 0.0.0.0)
-// - Robust room/admin/client stats
-// - Commands: start/stop/reset/blackout
-// - NTP-style sync (sync:ping -> sync:pong)
-
-const path = require('path');
-const express = require('express');
-const http = require('http');
-const { Server } = require('socket.io');
-
-const app = express();
-const server = http.createServer(app);
-const io = new Server(server, {
-  pingInterval: 10000,
-  pingTimeout: 5000,
-  cors: { origin: true }
-});
-
-// Serve static files
-app.use(express.static(path.join(__dirname, 'public')));
-
-// Single entry page (index.html handles role=admin|client)
-app.get('/', (req, res) => res.sendFile(path.join(__dirname, 'public', 'index.html')));
-
-// HF Spaces / Docker
-const HOST = '0.0.0.0';
-const PORT = process.env.PORT || 7860;
-
-// ---------- Helpers ----------
-function normRoom(x) { return String(x || 'default').trim().toLowerCase(); }
-function normRole(x) { return String(x || 'client').trim().toLowerCase(); }
-
-// Emit counts for a room using socket.data.role
-function emitStats(room) {
-  const ids = io.sockets.adapter.rooms.get(room) || new Set();
-  let numAdmins = 0, numClients = 0;
-  for (const id of ids) {
-    const s = io.sockets.sockets.get(id);
-    if (!s) continue;
-    (s.data?.role === 'admin') ? numAdmins++ : numClients++;
-  }
-  io.to(room).emit('stats', { numAdmins, numClients });
-}
-
-// ---------- Socket.io ----------
-io.on('connection', (socket) => {
-  const room = normRoom(socket.handshake.query.room);
-  const role = normRole(socket.handshake.query.role);
-
-  socket.data.room = room;
-  socket.data.role = role;
-
-  socket.join(room);
-  emitStats(room);
-
-  // Optional: let any client/admin force a refresh
-  socket.on('stats:refresh', () => emitStats(room));
-
-  // NTP-like sync
-  socket.on('sync:ping', (msg = {}) => {
-    const t1 = Date.now();
-    socket.emit('sync:pong', { t0: msg.t0, t1, t2: Date.now() });
-  });
-
-  // Admin commands
-  socket.on('admin:start', ({ delayMs = 3000, label = '' } = {}) => {
-    if (socket.data.role !== 'admin') return;
-    const startAt = Date.now() + Math.max(500, Number(delayMs));
-    io.to(room).emit('cmd', { type: 'start', startAt, label });
-  });
-
-  socket.on('admin:stop',  () => {
-    if (socket.data.role !== 'admin') return;
-    io.to(room).emit('cmd', { type: 'stop' });
-  });
-
-  socket.on('admin:reset', () => {
-    if (socket.data.role !== 'admin') return;
-    io.to(room).emit('cmd', { type: 'reset' });
-  });
-
-  socket.on('admin:blackout', ({ on = true } = {}) => {
-    if (socket.data.role !== 'admin') return;
-    io.to(room).emit('cmd', { type: 'blackout', on: !!on });
-  });
-
-  socket.on('disconnect', () => emitStats(room));
-});
-
-server.listen(PORT, HOST, () => {
-  console.log(`Timer server on http://${HOST}:${PORT}`);
-});
+// server.js — Pure async (monotonic) sync, no wall clock.
+// - Uses perf_hooks.performance.now() on server
+// - Robust room/admin/client stats
+// - Commands: start/stop/reset/blackout
+// - Redundant START + preSync burst for tight simultaneity
+// - Docker/Spaces-ready (binds 0.0.0.0, uses PORT)
+
+const path = require('path');
+const express = require('express');
+const http = require('http');
+const { Server } = require('socket.io');
+const { performance } = require('perf_hooks');
+
+const app = express();
+const server = http.createServer(app);
+const io = new Server(server, {
+  pingInterval: 10000,
+  pingTimeout: 5000,
+  cors: { origin: true }
+});
+
+// Serve static files
+app.use(express.static(path.join(__dirname, 'public')));
+
+// Single entry (merged Admin+Client UI lives in public/index.html)
+app.get('/', (req, res) => res.sendFile(path.join(__dirname, 'public', 'index.html')));
+
+const HOST = '0.0.0.0';
+const PORT = process.env.PORT || 7860;
+
+// ---------- Helpers ----------
+function normRoom(x) { return String(x || 'default').trim().toLowerCase(); }
+function normRole(x) { return String(x || 'client').trim().toLowerCase(); }
+
+function emitStats(room) {
+  const ids = io.sockets.adapter.rooms.get(room) || new Set();
+  let numAdmins = 0, numClients = 0;
+  for (const id of ids) {
+    const s = io.sockets.sockets.get(id);
+    if (!s) continue;
+    (s.data?.role === 'admin') ? numAdmins++ : numClients++;
+  }
+  io.to(room).emit('stats', { numAdmins, numClients });
+}
+
+// ---------- Socket.io ----------
+io.on('connection', (socket) => {
+  const room = normRoom(socket.handshake.query.room);
+  const role = normRole(socket.handshake.query.role);
+
+  socket.data.room = room;
+  socket.data.role = role;
+
+  socket.join(room);
+  emitStats(room);
+
+  socket.on('stats:refresh', () => emitStats(room));
+
+  // SYNC: server sends its monotonic time; client samples arrival with its own monotonic time
+  socket.on('sync:ping', () => {
+    const tS = performance.now(); // server monotonic ms
+    socket.emit('sync:pong', { tS });
+  });
+
+  // Admin commands
+  socket.on('admin:start', ({ delayMs = 3000, label = '' } = {}) => {
+    if (socket.data.role !== 'admin') return;
+    const startServerPerf = performance.now() + Math.max(800, Number(delayMs)); // future server perf time (ms)
+    const payload = { type: 'start', startServerPerf, label };
+
+    // Redundant emits for resilience
+    io.to(room).emit('cmd', payload);
+    setTimeout(() => io.to(room).emit('cmd', payload), 250);
+    setTimeout(() => io.to(room).emit('cmd', payload), 500);
+
+    // Ask clients to enter high-rate sync mode until T0
+    io.to(room).emit('cmd', { type: 'preSync', untilServerPerf: startServerPerf });
+  });
+
+  socket.on('admin:stop',  () => {
+    if (socket.data.role !== 'admin') return;
+    io.to(room).emit('cmd', { type: 'stop' });
+  });
+
+  socket.on('admin:reset', () => {
+    if (socket.data.role !== 'admin') return;
+    io.to(room).emit('cmd', { type: 'reset' });
+  });
+
+  socket.on('admin:blackout', ({ on = true } = {}) => {
+    if (socket.data.role !== 'admin') return;
+    io.to(room).emit('cmd', { type: 'blackout', on: !!on });
+  });
+
+  socket.on('disconnect', () => emitStats(room));
+});
+
+server.listen(PORT, HOST, () => {
+  console.log(`Timer server listening on http://${HOST}:${PORT}`);
+});