refactor: enhance session management and room joining logic in WebSocket handling

public/client.js

@@ -4,6 +4,8 @@ let ws;
 let reconnectAttempts = 0;
 let reconnectTimer = null;
 const outbox = [];
+let sessionId = localStorage.getItem('sessionId') || null;
+let lastRoomId = localStorage.getItem('lastRoomId') || null;
 function wsIsOpen() { return ws && ws.readyState === WebSocket.OPEN; }
 function sendMsg(obj) {
   if (wsIsOpen()) ws.send(JSON.stringify(obj));
@@ -23,6 +25,10 @@ function connectWS() {
   ws = new WebSocket(url);
   ws.addEventListener('open', () => {
     reconnectAttempts = 0;
+    // Try to resume session immediately
+    if (sessionId) {
+      try { ws.send(JSON.stringify({ type: 'resume', sessionId })); } catch {}
+    }
     // Flush queued messages
     setTimeout(() => {
       while (outbox.length && wsIsOpen()) {
@@ -89,6 +95,7 @@ function showRoom() { $lobby.classList.add('hidden'); $room.classList.remove('hi
 
 function renderRoom(room) {
   state.room = room;
+  try { if (room?.id) { lastRoomId = room.id; localStorage.setItem('lastRoomId', room.id); } } catch {}
   if (!room) { showLobby(); return; }
   showRoom();
   $roomId.textContent = room.id;
@@ -241,6 +248,10 @@ function handleMessage(ev) {
   const msg = JSON.parse(ev.data);
   if (msg.type === 'connected') {
     state.playerId = msg.playerId;
+    if (msg.sessionId && !sessionId) {
+      sessionId = msg.sessionId;
+      try { localStorage.setItem('sessionId', sessionId); } catch {}
+    }
     // Try to auto-apply stored name
     const stored = localStorage.getItem('playerName');
     if (stored) {
@@ -252,8 +263,28 @@ function handleMessage(ev) {
       }
       sendMsg({ type: 'set_name', name: stored });
     }
-    // Try to rejoin room if known
-    if (state.room?.id) sendMsg({ type: 'join_room', code: state.room.id });
+  // If we already have a sessionId, we'll resume instead of auto-joining here
+  if (!sessionId) {
+    const code = state.room?.id || lastRoomId || localStorage.getItem('lastRoomId');
+    if (code) sendMsg({ type: 'join_room', code });
+  }
+  }
+  if (msg.type === 'resume_result') {
+    if (msg.ok) {
+      if (msg.playerId) state.playerId = msg.playerId;
+      // If we have a known room, ensure we rejoin it
+      if (msg.roomId) {
+        // Update local roomId (we will receive a room_update shortly)
+        sendMsg({ type: 'join_room', code: msg.roomId });
+      } else {
+        const code = state.room?.id || lastRoomId || localStorage.getItem('lastRoomId');
+        if (code) sendMsg({ type: 'join_room', code });
+      }
+    } else {
+      // If resume failed, try to rejoin by last room code
+      const code = state.room?.id || lastRoomId || localStorage.getItem('lastRoomId');
+      if (code) sendMsg({ type: 'join_room', code });
+    }
   }
   if (msg.type === 'room_update') {
     renderRoom(msg.room);