feat: add AI voice transcription fallback for domestic Android ROMs

kouyu_english/lib/features/lesson/lesson_flow.dart

@@ -147,6 +147,7 @@ class _LessonFlowState extends State<LessonFlow> {
         content = _DialoguePendingStep(onOpenDialogue: widget.onOpenDialogue);
       case LessonStep.independent:
         content = _IndependentStep(
+          state: widget.state,
           segmentId: segment.id,
           keepRecording: widget.state.keepRecordings,
           activity: activity,
@@ -438,6 +439,8 @@ class _SpeakingStep extends StatefulWidget {
 class _SpeakingStepState extends State<_SpeakingStep> {
   bool listening = false;
   bool recording = false;
+  bool transcribing = false;
+  bool aiVoiceRecording = false;
   bool playingRecording = false;
   String transcript = '';
   String? recordingPath;
@@ -452,14 +455,83 @@ class _SpeakingStepState extends State<_SpeakingStep> {
   }
 
   Future<void> _toggleMic() async {
+    if (aiVoiceRecording) {
+      final path = await VoiceService.instance.stopRecording();
+      if (!mounted) return;
+      setState(() {
+        aiVoiceRecording = false;
+        listening = false;
+        transcribing = true;
+      });
+      if (path != null) {
+        final config = widget.state.aiConfig;
+        final text = await AiService.instance.transcribeAudio(
+          filePath: path,
+          provider: config.provider,
+          endpoint: config.endpoint,
+          model: config.model,
+        );
+        if (mounted) {
+          setState(() {
+            transcribing = false;
+            if (text != null && text.trim().isNotEmpty) {
+              transcript = text.trim();
+            }
+          });
+          if (text == null || text.trim().isEmpty) {
+            ScaffoldMessenger.of(context).showSnackBar(
+              const SnackBar(content: Text('未识别到清晰声音，请重试或点击“播放示范音”。')),
+            );
+          }
+        }
+      } else {
+        if (mounted) setState(() => transcribing = false);
+      }
+      return;
+    }
+
     if (listening) {
       await VoiceService.instance.stopListening();
       if (mounted) setState(() => listening = false);
       return;
     }
-    final ready = await VoiceService.instance.startListening((text, _) {
-      if (mounted) setState(() => transcript = text);
-    });
+
+    final ready = await VoiceService.instance.startListening(
+      (text, _) {
+        if (mounted) setState(() => transcript = text);
+      },
+      onStatus: (status) {
+        if (mounted && (status == 'notListening' || status == 'done')) {
+          setState(() => listening = false);
+        }
+      },
+      onError: (err) {
+        if (mounted) {
+          setState(() => listening = false);
+        }
+      },
+    );
+
+    if (!ready) {
+      final recordStarted = await VoiceService.instance.startRecording();
+      if (mounted) {
+        setState(() {
+          aiVoiceRecording = recordStarted;
+          listening = recordStarted;
+        });
+        if (recordStarted) {
+          ScaffoldMessenger.of(context).showSnackBar(
+            const SnackBar(content: Text('已启动麦克风录音，跟读完成后再次点击，AI 将自动转写发音。')),
+          );
+        } else {
+          ScaffoldMessenger.of(context).showSnackBar(
+            const SnackBar(content: Text('无法访问麦克风，请检查手机录音权限。')),
+          );
+        }
+      }
+      return;
+    }
+
     if (mounted) setState(() => listening = ready);
   }
 
@@ -526,8 +598,10 @@ class _SpeakingStepState extends State<_SpeakingStep> {
           ),
         ),
         SecondaryButton(
-          label: listening ? '停止录音' : '使用麦克风跟读',
-          onPressed: _toggleMic,
+          label: transcribing
+              ? '正在 AI 识别发音…'
+              : (listening ? '停止录音并识别' : '使用麦克风跟读'),
+          onPressed: transcribing ? null : _toggleMic,
         ),
         SecondaryButton(
           label: recording ? '停止本机录音' : '录音后回听',
@@ -871,6 +945,7 @@ class _DialoguePendingStep extends StatelessWidget {
 
 class _IndependentStep extends StatefulWidget {
   const _IndependentStep({
+    required this.state,
     required this.segmentId,
     required this.keepRecording,
     required this.activity,
@@ -883,6 +958,7 @@ class _IndependentStep extends StatefulWidget {
     required this.onContinue,
     required this.onLater,
   });
+  final AppState state;
   final LessonActivity activity;
   final String segmentId;
   final bool keepRecording;
@@ -902,6 +978,8 @@ class _IndependentStep extends StatefulWidget {
 class _IndependentStepState extends State<_IndependentStep> {
   bool listening = false;
   bool recording = false;
+  bool transcribing = false;
+  bool aiVoiceRecording = false;
   bool playingRecording = false;
   bool usedVoice = false;
   bool transcriptEdited = false;
@@ -968,27 +1046,95 @@ class _IndependentStepState extends State<_IndependentStep> {
   }
 
   Future<void> _toggleMic() async {
+    if (aiVoiceRecording) {
+      final path = await VoiceService.instance.stopRecording();
+      if (!mounted) return;
+      setState(() {
+        aiVoiceRecording = false;
+        listening = false;
+        transcribing = true;
+      });
+      if (path != null) {
+        final config = widget.state.aiConfig;
+        final text = await AiService.instance.transcribeAudio(
+          filePath: path,
+          provider: config.provider,
+          endpoint: config.endpoint,
+          model: config.model,
+        );
+        if (mounted) {
+          setState(() {
+            transcribing = false;
+            if (text != null && text.trim().isNotEmpty) {
+              widget.controller.text = text.trim();
+              usedVoice = true;
+              lastTranscript = text.trim();
+              transcriptEdited = false;
+            }
+          });
+          widget.onChanged();
+          if (text == null || text.trim().isEmpty) {
+            ScaffoldMessenger.of(context).showSnackBar(
+              const SnackBar(content: Text('未识别到声音，请重试或直接打字输入。')),
+            );
+          }
+        }
+      } else {
+        if (mounted) setState(() => transcribing = false);
+      }
+      return;
+    }
+
     if (listening) {
       await VoiceService.instance.stopListening();
       if (mounted) setState(() => listening = false);
       return;
     }
-    final ready = await VoiceService.instance.startListening((text, _) {
-      if (!mounted) return;
-      setState(() {
-        widget.controller.text = text;
-        usedVoice = true;
-        lastTranscript = text;
-        transcriptEdited = false;
-      });
-      widget.onChanged();
-    });
-    if (mounted) setState(() => listening = ready);
-    if (!ready && mounted) {
-      ScaffoldMessenger.of(
-        context,
-      ).showSnackBar(const SnackBar(content: Text('语音识别不可用；你仍可输入英文完成写作练习。')));
+
+    final ready = await VoiceService.instance.startListening(
+      (text, _) {
+        if (!mounted) return;
+        setState(() {
+          widget.controller.text = text;
+          usedVoice = true;
+          lastTranscript = text;
+          transcriptEdited = false;
+        });
+        widget.onChanged();
+      },
+      onStatus: (status) {
+        if (mounted && (status == 'notListening' || status == 'done')) {
+          setState(() => listening = false);
+        }
+      },
+      onError: (err) {
+        if (mounted) {
+          setState(() => listening = false);
+        }
+      },
+    );
+
+    if (!ready) {
+      final recordStarted = await VoiceService.instance.startRecording();
+      if (mounted) {
+        setState(() {
+          aiVoiceRecording = recordStarted;
+          listening = recordStarted;
+        });
+        if (recordStarted) {
+          ScaffoldMessenger.of(context).showSnackBar(
+            const SnackBar(content: Text('已启动麦克风录音，说完后再次点击，AI 将自动转写为英文。')),
+          );
+        } else {
+          ScaffoldMessenger.of(context).showSnackBar(
+            const SnackBar(content: Text('无法访问麦克风，请检查手机录音权限。')),
+          );
+        }
+      }
+      return;
     }
+
+    if (mounted) setState(() => listening = ready);
   }
 
   @override