possible to exclude levels and change how questions are served

lib/src/screens/vocab_screen.dart

@@ -21,8 +21,7 @@ class _QuizState {
   Key key = UniqueKey();
   String? selectedOption;
   bool showResult = false;
-  List<VocabularyItem> shuffledDeck = [];
-  int currentIndex = 0;
+  Set<int> wrongItems = {};
 }
 
 class VocabScreen extends StatefulWidget {
@@ -40,10 +39,13 @@ class _VocabScreenState extends State<VocabScreen>
   bool _isAnswering = false;
   String _status = 'Loading deck...';
   final DistractorGenerator _dg = DistractorGenerator();
+  final Random _random = Random();
   final _audioPlayer = AudioPlayer();
 
   final _quizStates = [_QuizState(), _QuizState(), _QuizState()];
   _QuizState get _currentQuizState => _quizStates[_tabController.index];
+  final _sessionDecks = <int, List<VocabularyItem>>{};
+  final _sessionDeckSizes = <int, int>{};
 
   bool _playIncorrectSound = true;
   bool _playCorrectSound = true;
@@ -114,6 +116,40 @@ class _VocabScreenState extends State<VocabScreen>
         _apiKeyMissing = false;
       });
 
+      final disabledLevels = <int>{};
+      final itemsByLevel = <int, List<VocabularyItem>>{};
+      for (final item in _deck) {
+        (itemsByLevel[item.level] ??= []).add(item);
+      }
+
+      itemsByLevel.forEach((level, items) {
+        final allSrsItems = items.expand((item) => item.srsItems.values).toList();
+        if (allSrsItems.isNotEmpty && allSrsItems.every((srs) => srs.disabled)) {
+          disabledLevels.add(level);
+        }
+      });
+
+      for (var i = 0; i < _tabController.length; i++) {
+        final mode = _modeForIndex(i);
+        var filteredDeck = _deck.where((item) {
+          if (disabledLevels.contains(item.level)) {
+            return false;
+          }
+          final srsItem = item.srsItems[mode.toString()];
+          return srsItem == null || !srsItem.disabled;
+        }).toList();
+
+        if (mode == QuizMode.audioToEnglish) {
+          filteredDeck = filteredDeck
+              .where((item) => item.pronunciationAudios.isNotEmpty)
+              .toList();
+        }
+
+        filteredDeck.shuffle(_random);
+        _sessionDecks[i] = filteredDeck;
+        _sessionDeckSizes[i] = filteredDeck.length;
+      }
+
       for (var i = 0; i < _tabController.length; i++) {
         _nextQuestion(i);
       }
@@ -147,47 +183,20 @@ class _VocabScreenState extends State<VocabScreen>
   }
 
   void _nextQuestion([int? index]) {
-    if (_deck.isEmpty) return;
+    final tabIndex = index ?? _tabController.index;
+    final quizState = _quizStates[tabIndex];
+    final sessionDeck = _sessionDecks[tabIndex];
+    final mode = _modeForIndex(tabIndex);
 
-    final quizState = _quizStates[index ?? _tabController.index];
-    final mode = _modeForIndex(index ?? _tabController.index);
-
-    List<VocabularyItem> currentDeckForMode = _deck;
-    if (mode == QuizMode.audioToEnglish) {
-      currentDeckForMode = _deck
-          .where((item) => item.pronunciationAudios.isNotEmpty)
-          .toList();
-      if (currentDeckForMode.isEmpty) {
-        setState(() {
-          _status = 'No vocabulary with audio found.';
-          quizState.current = null;
-        });
-        return;
-      }
-    }
-
-    if (quizState.shuffledDeck.isEmpty ||
-        quizState.currentIndex >= quizState.shuffledDeck.length) {
-      quizState.shuffledDeck = currentDeckForMode.toList();
-      quizState.shuffledDeck.sort((a, b) {
-        final aSrsItem =
-            a.srsItems[mode.toString()] ??
-            SrsItem(subjectId: a.id, quizMode: mode);
-        final bSrsItem =
-            b.srsItems[mode.toString()] ??
-            SrsItem(subjectId: b.id, quizMode: mode);
-        final stageComparison = aSrsItem.srsStage.compareTo(bSrsItem.srsStage);
-        if (stageComparison != 0) {
-          return stageComparison;
-        }
-        return aSrsItem.lastAsked.compareTo(bSrsItem.lastAsked);
+    if (sessionDeck == null || sessionDeck.isEmpty) {
+      setState(() {
+        quizState.current = null;
+        _status = 'Quiz complete!';
       });
-      quizState.currentIndex = 0;
+      return;
     }
 
-    quizState.current = quizState.shuffledDeck[quizState.currentIndex];
-    quizState.currentIndex++;
-
+    quizState.current = sessionDeck.removeAt(0);
     quizState.key = UniqueKey();
     quizState.correctAnswers = [];
     quizState.options = [];
@@ -218,6 +227,10 @@ class _VocabScreenState extends State<VocabScreen>
     setState(() {
       _isAnswering = false;
     });
+
+    if (mode == QuizMode.audioToEnglish) {
+      _playCurrentAudio(playOnLoad: true);
+    }
   }
 
   Future<void> _playCurrentAudio({bool playOnLoad = false}) async {
@@ -247,6 +260,8 @@ class _VocabScreenState extends State<VocabScreen>
 
     final repo = Provider.of<VocabDeckRepository>(context, listen: false);
     final current = quizState.current!;
+    final tabIndex = _tabController.index;
+    final sessionDeck = _sessionDecks[tabIndex]!;
 
     final srsKey = mode.toString();
 
@@ -255,16 +270,21 @@ class _VocabScreenState extends State<VocabScreen>
     final srsItem =
         srsItemNullable ?? SrsItem(subjectId: current.id, quizMode: mode);
 
-    quizState.asked += 1;
     quizState.selectedOption = option;
     quizState.showResult = true;
     setState(() {});
 
     if (isCorrect) {
-      quizState.score += 1;
+      quizState.asked += 1;
+      if (!quizState.wrongItems.contains(current.id)) {
+        quizState.score += 1;
+      }
       srsItem.srsStage += 1;
     } else {
       srsItem.srsStage = max(0, srsItem.srsStage - 1);
+      sessionDeck.add(current);
+      sessionDeck.shuffle(_random);
+      quizState.wrongItems.add(current.id);
       if (_playIncorrectSound) {
         await _audioPlayer.play(AssetSource('sfx/incorrect.wav'));
       }
@@ -325,7 +345,11 @@ class _VocabScreenState extends State<VocabScreen>
       _isAnswering = true;
     });
 
-    _nextQuestion();
+    Future.delayed(const Duration(milliseconds: 900), () {
+      if (mounted) {
+        _nextQuestion();
+      }
+    });;
   }
 
   @override
@@ -360,6 +384,23 @@ class _VocabScreenState extends State<VocabScreen>
       );
     }
 
+    if (_loading) {
+      return Scaffold(
+        appBar: AppBar(
+          title: const Text('Vocabulary Quiz'),
+          bottom: TabBar(
+            controller: _tabController,
+            tabs: const [
+              Tab(text: 'Vocab→English'),
+              Tab(text: 'English→Vocab'),
+              Tab(text: 'Listening'),
+            ],
+          ),
+        ),
+        body: const Center(child: CircularProgressIndicator()),
+      );
+    }
+
     return Scaffold(
       appBar: AppBar(
         title: const Text('Vocabulary Quiz'),
@@ -383,6 +424,16 @@ class _VocabScreenState extends State<VocabScreen>
     final quizState = _quizStates[index];
     final mode = _modeForIndex(index);
 
+    if (quizState.current == null) {
+      return Center(
+        child: Text(
+          _status,
+          style: TextStyle(
+              fontSize: 24, color: Theme.of(context).colorScheme.onSurface),
+        ),
+      );
+    }
+
     Widget promptWidget;
 
     if (quizState.current == null) {
@@ -424,20 +475,27 @@ class _VocabScreenState extends State<VocabScreen>
       padding: const EdgeInsets.all(16.0),
       child: Column(
         children: [
-          Row(
+          Column(
+            crossAxisAlignment: CrossAxisAlignment.start,
             children: [
-              Expanded(
-                child: Text(
-                  _status,
-                  style: TextStyle(
-                    color: Theme.of(context).colorScheme.onSurface,
-                  ),
+              Text(
+                '${quizState.asked} / ${_sessionDeckSizes[index] ?? 0}',
+                style: TextStyle(
+                  color: Theme.of(context).colorScheme.onSurface,
+                  fontSize: 18,
+                  fontWeight: FontWeight.bold,
                 ),
               ),
-              if (_loading)
-                CircularProgressIndicator(
-                  color: Theme.of(context).colorScheme.primary,
-                ),
+              const SizedBox(height: 4),
+              LinearProgressIndicator(
+                value: (_sessionDeckSizes[index] ?? 0) > 0
+                    ? quizState.asked / (_sessionDeckSizes[index] ?? 1)
+                    : 0,
+                backgroundColor:
+                    Theme.of(context).colorScheme.surfaceContainerHighest,
+                valueColor: AlwaysStoppedAnimation<Color>(
+                    Theme.of(context).colorScheme.primary),
+              ),
             ],
           ),
           const SizedBox(height: 18),
@@ -462,10 +520,9 @@ class _VocabScreenState extends State<VocabScreen>
                 OptionsGrid(
                   options: quizState.options,
                   onSelected: _isAnswering ? (option) {} : _answer,
-                  isDisabled: false,
-                  selectedOption: null,
-                  correctAnswers: [],
-                  showResult: false,
+                  showResult: quizState.showResult,
+                  selectedOption: quizState.selectedOption,
+                  correctAnswers: quizState.correctAnswers,
                 ),
                 const SizedBox(height: 8),
                 Text(