feat: 完善听力口语辅助状态记录、练习分块与复习抽查间隔机制

kouyu_english/lib/features/lesson/lesson_flow.dart

@@ -44,11 +44,7 @@ class _LessonFlowState extends State<LessonFlow> {
   final independentController = TextEditingController();
   int selectedAnswer = -1;
 
-  /// Set once a wrong meaning is picked, so only a first-try choice counts as
-  /// recognition evidence.
-  bool listeningMissed = false;
   int previewIndex = 0;
-  bool listeningAudioPlayed = false;
   bool showWritingHelp = true;
   bool showIndependentHelp = false;
   LessonSegment get segment {
@@ -56,11 +52,9 @@ class _LessonFlowState extends State<LessonFlow> {
     return lesson.segments[widget.state.activeSegmentIndexFor(lesson.id)];
   }
 
-  LessonActivity get activity =>
-      activityBySegmentId(segment.id);
+  LessonActivity get activity => activityBySegmentId(segment.id);
 
-  List<VocabularyItem> get previewItems =>
-      vocabularyBySegmentId(segment.id);
+  List<VocabularyItem> get previewItems => vocabularyBySegmentId(segment.id);
 
   @override
   void initState() {
@@ -122,17 +116,21 @@ class _LessonFlowState extends State<LessonFlow> {
           options: listeningOptions,
           correctAnswer: activity.answers.first,
           selectedAnswer: selectedAnswer,
-          audioPlayed: listeningAudioPlayed,
-          missed: listeningMissed,
-          onSelected: (value) => setState(() {
-            selectedAnswer = value;
+          audioPlayed: widget.state.listeningAudioPlayed,
+          audioUnavailable: widget.state.listeningAudioUnavailable,
+          support: widget.state.listeningSupport,
+          missed: widget.state.listeningAttempts > 0,
+          onSelected: (value) {
+            setState(() => selectedAnswer = value);
             if (listeningOptions[value] != activity.answers.first) {
-              listeningMissed = true;
+              widget.state.recordListeningMiss();
             }
-          }),
-          onPlayed: () => setState(() => listeningAudioPlayed = true),
+          },
+          onPlayed: () => widget.state.recordListeningPlayback(),
+          onAudioFailed: widget.state.recordListeningAudioUnavailable,
+          onSlowPlayed: () => widget.state.recordListeningPlayback(slow: true),
           onLookup: () {
-            setState(() => listeningMissed = true);
+            widget.state.revealListeningTranscript();
             showLexiconLookup(
               context,
               state: widget.state,
@@ -142,8 +140,7 @@ class _LessonFlowState extends State<LessonFlow> {
           onContinue:
               selectedAnswer >= 0 &&
                   listeningOptions[selectedAnswer] == activity.answers.first
-              ? () =>
-                    widget.state.completeListening(recognized: !listeningMissed)
+              ? () => widget.state.completeListening(recognized: true)
               : null,
         );
       case LessonStep.speaking:
@@ -152,8 +149,13 @@ class _LessonFlowState extends State<LessonFlow> {
           segmentId: segment.id,
           text: activity.speaking,
           tip: activity.speakingTip,
+          chunks: activity.speakingChunks,
+          examples: activity.speakingExamples,
+          buildIndex: widget.state.sentenceBuildIndex,
+          onBuildProgress: widget.state.recordSentenceBuildProgress,
           keepRecording: widget.state.keepRecordings,
-          onContinue: widget.state.completeSpeaking,
+          onContinue: (practiced) =>
+              widget.state.completeSpeaking(practiced: practiced),
         );
       case LessonStep.reading:
         content = _ReadingStep(
@@ -191,8 +193,11 @@ class _LessonFlowState extends State<LessonFlow> {
           },
           onToggleHelp: () =>
               setState(() => showWritingHelp = !showWritingHelp),
-          onContinue: (usedAiFeedback) => widget.state.completeWriting(
-            assisted: showWritingHelp || usedAiFeedback,
+          onContinue: (verified) => widget.state.completeWriting(
+            // The example is visible when this guided step opens. Hiding it
+            // later cannot turn the same answer into an independent attempt.
+            assisted: true,
+            verified: verified,
             rawAnswer: writingController.text.trim(),
           ),
         );
@@ -221,9 +226,10 @@ class _LessonFlowState extends State<LessonFlow> {
               initialText: activity.independentPrompt,
             );
           },
-          onContinue: (spoken, recordingPath, aiCorrected) =>
+          onContinue: (spoken, recordingPath, aiCorrected, verified) =>
               widget.state.completeIndependentAttempt(
                 assisted: showIndependentHelp || aiCorrected,
+                verified: verified,
                 spoken: spoken,
                 rawAnswer: independentController.text.trim(),
                 recordingPath: recordingPath,
@@ -234,6 +240,7 @@ class _LessonFlowState extends State<LessonFlow> {
       case LessonStep.complete:
         content = _CompletionStep(
           assisted: widget.state.independentAttemptAssisted,
+          pending: widget.state.independentAttemptPending,
           isFinalSegment:
               widget.state.activeSegmentIndexFor(lesson.id) ==
               lesson.segments.length - 1,
@@ -343,11 +350,13 @@ class _DialoguePendingStep extends StatelessWidget {
 class _CompletionStep extends StatelessWidget {
   const _CompletionStep({
     required this.assisted,
+    required this.pending,
     required this.isFinalSegment,
     required this.nextSegmentNumber,
     required this.onFinish,
   });
   final bool assisted;
+  final bool pending;
   final bool isFinalSegment;
   final int nextSegmentNumber;
   final VoidCallback onFinish;
@@ -362,7 +371,13 @@ class _CompletionStep extends StatelessWidget {
           isFinalSegment ? '你完成了这节课的练习。' : '你完成了当前小段的练习。',
           style: Theme.of(context).textTheme.headlineMedium,
         ),
-        Text(assisted ? '独立尝试使用了帮助，系统会安排不同题再练一次。' : '这次独立尝试已记录，后续会在不同情境中复练。'),
+        Text(
+          pending
+              ? '练习已保存，但答案未经 AI 核验，不计入独立掌握。后续会安排复练。'
+              : assisted
+              ? '独立尝试使用了帮助，系统会安排不同题再练一次。'
+              : '这次独立尝试已记录，后续会在不同情境中复练。',
+        ),
         if (!isFinalSegment) Text('回到首页后，下次从第 $nextSegmentNumber 段继续。'),
         PrimaryButton(label: '回到首页', onPressed: onFinish),
       ],
@@ -371,20 +386,28 @@ class _CompletionStep extends StatelessWidget {
 }
 
 class _AudioRow extends StatelessWidget {
-  const _AudioRow({required this.label, this.speech, this.onPlayed});
+  const _AudioRow({
+    required this.label,
+    this.speech,
+    this.onPlayed,
+    this.onFailed,
+    this.showSlow = true,
+  });
   final String label;
   final String? speech;
   final VoidCallback? onPlayed;
+  final VoidCallback? onFailed;
+  final bool showSlow;
 
   @override
   Widget build(BuildContext context) => Row(
     children: [
       IconButton.filled(
         onPressed: () async {
-          try {
-            await VoiceService.instance.speak(speech ?? label);
-          } finally {
+          if (await VoiceService.instance.speak(speech ?? label)) {
             onPlayed?.call();
+          } else {
+            onFailed?.call();
           }
         },
         icon: const Icon(Icons.play_arrow),
@@ -393,10 +416,10 @@ class _AudioRow extends StatelessWidget {
       Expanded(
         child: InkWell(
           onTap: () async {
-            try {
-              await VoiceService.instance.speak(speech ?? label);
-            } finally {
+            if (await VoiceService.instance.speak(speech ?? label)) {
               onPlayed?.call();
+            } else {
+              onFailed?.call();
             }
           },
           child: Padding(
@@ -405,16 +428,18 @@ class _AudioRow extends StatelessWidget {
           ),
         ),
       ),
-      TextButton(
-        onPressed: () async {
-          try {
-            await VoiceService.instance.speak(speech ?? label, slow: true);
-          } finally {
-            onPlayed?.call();
-          }
-        },
-        child: const Text('慢速'),
-      ),
+      if (showSlow)
+        TextButton(
+          onPressed: () async {
+            if (await VoiceService.instance.speak(
+              speech ?? label,
+              slow: true,
+            )) {
+              onPlayed?.call();
+            }
+          },
+          child: const Text('慢速'),
+        ),
     ],
   );
 }