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

public/js/main.js

@@ -1,8 +1,8 @@
 import { $audio, $copyRoomCode, $leaveRoom, $nameDisplay, $nameLobby, $npArtist, $npTitle, $npYear, $pauseBtn, $placeBtn, $readyChk, $roomId, $roomCode, $slotSelect, $startGame, $volumeSlider, $playBtn, $nextBtn, $createRoom, $joinRoom, $lobby, $room, $setNameLobby, $guessTitle, $guessArtist, $answerResult } from './dom.js';
 import { state } from './state.js';
-import { connectWS, sendMsg } from './ws.js';
+import { connectWS, sendMsg, cacheSessionId, cacheLastRoomId } from './ws.js';
 import { renderRoom } from './render.js';
-import { initAudioUI, applySync } from './audio.js';
+import { initAudioUI, applySync, stopAudioPlayback } from './audio.js';
 
 function showToast(msg) {
   const el = document.getElementById('toast');
@@ -18,6 +18,9 @@ function showToast(msg) {
 
 function handleConnected(msg) {
   state.playerId = msg.playerId;
+  if (msg.sessionId) {
+    cacheSessionId(msg.sessionId);
+  }
   const stored = localStorage.getItem('playerName');
   if (stored) {
     if ($nameLobby && $nameLobby.value !== stored) {
@@ -28,12 +31,14 @@ function handleConnected(msg) {
     }
     sendMsg({ type: 'set_name', name: stored });
   }
-  if (state.room?.id) {
-    sendMsg({ type: 'join_room', code: state.room.id });
+  const last = state.room?.id || localStorage.getItem('lastRoomId');
+  if (last && !localStorage.getItem('sessionId')) {
+    sendMsg({ type: 'join_room', code: last });
   }
 }
 
 function handleRoomUpdate(msg) {
+  if (msg?.room?.id) cacheLastRoomId(msg.room.id);
   renderRoom(msg.room);
 }
 
@@ -134,6 +139,16 @@ function handleGameEnded(msg) {
 function onMessage(ev) {
   const msg = JSON.parse(ev.data);
   switch (msg.type) {
+    case 'resume_result':
+      if (msg.ok) {
+        if (msg.playerId) state.playerId = msg.playerId;
+        const code = msg.roomId || state.room?.id || localStorage.getItem('lastRoomId');
+        if (code) sendMsg({ type: 'join_room', code });
+      } else {
+        const code = state.room?.id || localStorage.getItem('lastRoomId');
+        if (code) sendMsg({ type: 'join_room', code });
+      }
+      break;
     case 'connected':
       handleConnected(msg);
       break;
@@ -211,6 +226,7 @@ function wireUi() {
   });
   wire($leaveRoom, 'click', () => {
     sendMsg({ type: 'leave_room' });
+  stopAudioPlayback();
     state.room = null;
     $lobby.classList.remove('hidden');
     $room.classList.add('hidden');