Restore private play again with rollback-safe migration

client/src/components/Results.jsx

@@ -12,7 +12,7 @@ import ProfileModal from './ProfileModal.jsx';
 
 function Results({ onShowLeaderboard }) {
   const navigate = useNavigate();
-  const { raceState, typingState, resetRace, joinPublicRace } = useRace();
+  const { raceState, typingState, resetRace, joinPublicRace, playAgain } = useRace();
   const { isRunning, endTutorial } = useTutorial();
   const { user } = useAuth();
   // State for profile modal
@@ -353,13 +353,20 @@ function Results({ onShowLeaderboard }) {
 
         {raceState.type === 'practice' ? renderPracticeResults() : renderRaceResults()}
 
+        {/* Play Again button for private match host */}
+        {raceState.type === 'private' && raceState.completed && user?.netid === raceState.hostNetId && (
+          <button className="back-btn" onClick={playAgain}>
+            Play Again
+          </button>
+        )}
+
         {/* Queue Next Race button for quick matches */}
         {raceState.type === 'public' && (
           <button className="back-btn" onClick={handleQueueNext}>
             Queue Another Race
           </button>
         )}
-        
+
         <button className="back-btn back-to-menu-btn" onClick={handleBack}>
           Back to Menu
         </button>

client/src/context/RaceContext.jsx

@@ -567,6 +567,43 @@ export const RaceProvider = ({ children }) => {
       resetAnticheatState();
     };
 
+    // Handle play again – host created a new lobby and all players are migrated
+    const handleLobbyPlayAgain = (data) => {
+      console.log('Play again – joining new lobby:', data.code);
+      resetAnticheatState();
+      setInactivityState({
+        warning: false,
+        warningMessage: '',
+        kicked: false,
+        kickMessage: '',
+        redirectToHome: false
+      });
+      setTypingState({
+        input: '', position: 0, correctChars: 0, errors: 0,
+        completed: false, wpm: 0, accuracy: 0, lockedPosition: 0
+      });
+      setRaceState({
+        code: data.code,
+        type: data.type || 'private',
+        lobbyId: data.lobbyId,
+        hostNetId: data.hostNetId,
+        snippet: data.snippet ? { ...data.snippet, text: sanitizeSnippetText(data.snippet.text) } : null,
+        players: data.players || [],
+        startTime: null,
+        inProgress: false,
+        completed: false,
+        results: [],
+        manuallyStarted: false,
+        timedTest: {
+          enabled: data.settings?.testMode === 'timed',
+          duration: data.settings?.testDuration || 15
+        },
+        snippetFilters: data.settings?.snippetFilters || { difficulty: 'all', type: 'all', department: 'all' },
+        settings: data.settings || { testMode: 'snippet', testDuration: 15 },
+        countdown: null
+      });
+    };
+
     // Register event listeners
     socket.on('race:joined', handleRaceJoined);
     socket.on('race:playersUpdate', handlePlayersUpdate);
@@ -588,6 +625,7 @@ export const RaceProvider = ({ children }) => {
     socket.on('race:playerLeft', handlePlayerLeft);
     socket.on('anticheat:lock', handleAnticheatLock);
     socket.on('anticheat:reset', handleAnticheatReset);
+    socket.on('lobby:playAgain', handleLobbyPlayAgain);
 
     // Clean up on unmount
     return () => {
@@ -611,6 +649,7 @@ export const RaceProvider = ({ children }) => {
       socket.off('race:playerLeft', handlePlayerLeft);
       socket.off('anticheat:lock', handleAnticheatLock);
       socket.off('anticheat:reset', handleAnticheatReset);
+      socket.off('lobby:playAgain', handleLobbyPlayAgain);
       socket.off('snippetNotFound', handleSnippetNotFound); // Cleanup snippet not found listener
     };
     // Add raceState.snippet?.id to dependency array to reset typing state on snippet change
@@ -1080,6 +1119,16 @@ export const RaceProvider = ({ children }) => {
     });
   };
 
+  const playAgain = () => {
+    if (!socket || !connected || !raceState.code || raceState.type !== 'private') return;
+    socket.emit('lobby:playAgain', { code: raceState.code }, (response) => {
+      if (!response.success) {
+        console.error('Failed to play again:', response.error);
+      }
+      // State update handled by lobby:playAgain listener
+    });
+  };
+
   // joinPrivateLobby is declared earlier with useCallback to avoid TDZ
 
   const kickPlayer = (targetNetId) => {
@@ -1192,6 +1241,7 @@ export const RaceProvider = ({ children }) => {
         kickPlayer,
         updateLobbySettings,
         startPrivateRace,
+        playAgain,
         setPlayerReady,
         handleInput,
         updateProgress,

client/src/pages/Lobby.jsx

@@ -91,12 +91,26 @@ function Lobby() {
   // --- TestConfigurator State ---
   // Use settings directly from raceState now that context handles it
   const currentSettings = raceState.settings || { testMode: 'snippet', testDuration: 15 };
-  // Local state for filters not yet in raceState.settings
-  const [snippetDifficulty, setSnippetDifficulty] = useState('');
-  const [snippetCategory, setSnippetCategory] = useState('');
-  const [snippetSubject, setSnippetSubject] = useState('');
+  const currentSnippetFilters = currentSettings.snippetFilters || {
+    difficulty: 'all',
+    type: 'all',
+    department: 'all'
+  };
+  const [snippetDifficulty, setSnippetDifficulty] = useState(currentSnippetFilters.difficulty || 'all');
+  const [snippetCategory, setSnippetCategory] = useState(currentSnippetFilters.type || 'all');
+  const [snippetSubject, setSnippetSubject] = useState(currentSnippetFilters.department || 'all');
   // --- ---
 
+  useEffect(() => {
+    setSnippetDifficulty(currentSnippetFilters.difficulty || 'all');
+    setSnippetCategory(currentSnippetFilters.type || 'all');
+    setSnippetSubject(currentSnippetFilters.department || 'all');
+  }, [
+    currentSnippetFilters.department,
+    currentSnippetFilters.difficulty,
+    currentSnippetFilters.type
+  ]);
+
   // Handler for settings changes (only host can trigger)
   // Generic handler factory that maps a particular setter (identified by a string
   // rather than the actual function reference) to a callback that
@@ -273,7 +287,7 @@ function Lobby() {
                     loadNewSnippet={loadNewSnippet}
                     snippetError={snippetError}
                     isLobby
-                    allowTimed={false}
+                    allowTimed={currentSettings.testMode === 'timed'}
                     onShowLeaderboard={() => {}} // Disable leaderboard button in lobby
                   />
                 ) : (

client/src/pages/Race.jsx

@@ -70,6 +70,19 @@ function Race() {
       navigate('/home', { replace: true });
     }
   }, [raceState.code, navigate]);
+
+  // After play again, navigate back to the new private lobby
+  useEffect(() => {
+    if (
+      raceState.type === 'private' &&
+      raceState.code &&
+      !raceState.inProgress &&
+      !raceState.completed &&
+      raceState.countdown === null
+    ) {
+      navigate(`/lobby/${raceState.code}`, { replace: true });
+    }
+  }, [raceState.code, raceState.type, raceState.inProgress, raceState.completed, raceState.countdown, navigate]);
 
   // Handle back button
   const handleBack = () => {