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/steps/independent_step.dart

@@ -27,7 +27,12 @@ class _IndependentStep extends StatefulWidget {
   final VoidCallback onChanged;
   final VoidCallback onNeedHelp;
   final VoidCallback onLookup;
-  final void Function(bool spoken, String? recordingPath, bool aiCorrected)
+  final void Function(
+    bool spoken,
+    String? recordingPath,
+    bool aiCorrected,
+    bool verified,
+  )
   onContinue;
   final VoidCallback onLater;
 
@@ -57,7 +62,8 @@ class _IndependentStepState extends State<_IndependentStep>
     super.dispose();
   }
 
-  void _submit() {
+  Future<void> _submit() async {
+    if (!widget.canContinue || checkingWithAi) return;
     final shortfall = independentShortfall(
       widget.segmentId,
       widget.controller.text,
@@ -66,12 +72,20 @@ class _IndependentStepState extends State<_IndependentStep>
       setState(() => validationError = shortfall);
       return;
     }
+    if (widget.state.aiProvider == AiProviderType.mock) {
+      _finish(verified: false);
+      return;
+    }
+    await _checkWithAi();
+    if (!mounted) return;
+    if (aiCheck?.verdict == 'accepted') _finish(verified: true);
+  }
+
+  void _finish({required bool verified}) {
     ScaffoldMessenger.of(context).showSnackBar(
       SnackBar(
         content: Text(
-          aiCheck?.verdict == 'accepted'
-              ? '通过：用上了本段要练的表达，AI 也没发现拼写或语法问题。'
-              : '通过：用上了本段要练的表达。',
+          verified ? '通过：用上了本段要练的表达，AI 也没发现拼写或语法问题。' : '练习已保存；答案未经核验，不计入独立掌握。',
         ),
       ),
     );
@@ -79,6 +93,7 @@ class _IndependentStepState extends State<_IndependentStep>
       usedVoice && !transcriptEdited,
       widget.keepRecording ? recordingPath : null,
       aiCorrected,
+      verified,
     );
   }
 
@@ -90,13 +105,9 @@ class _IndependentStepState extends State<_IndependentStep>
 
   Future<void> _checkWithAi() async {
     final answer = widget.controller.text.trim();
-    if (answer.isEmpty || checkingWithAi) return;
-    if (widget.state.aiProvider == AiProviderType.mock) {
-      setState(() => aiCheckError = '请先在“我的”配置 AI 服务；本地检查仍可继续学习。');
-      return;
-    }
     setState(() {
       checkingWithAi = true;
+      aiCheck = null;
       aiCheckError = null;
     });
     final feedback = await AiService.instance.capabilities.evaluation
@@ -119,9 +130,11 @@ class _IndependentStepState extends State<_IndependentStep>
       checkingWithAi = false;
       aiCheck = feedback;
       aiCheckError = feedback == null
-          ? '暂时无法获得 AI 检查结果。你的答案保留在这里，可稍后重试或直接提交。'
+          ? '暂时无法核验答案。可重试，或仅保存练习继续。'
+          : feedback.verdict == 'uncertain'
+          ? 'AI 无法确定答案是否正确。可重试，或仅保存练习继续。'
           : null;
-      if (feedback != null && feedback.verdict != 'accepted') {
+      if (feedback?.verdict == 'rewrite') {
         aiCorrected = true;
       }
     });
@@ -191,6 +204,11 @@ class _IndependentStepState extends State<_IndependentStep>
         const Eyebrow('试着自己写 / 说一次 · 约 1 分钟'),
         Text('现在不看句框。', style: Theme.of(context).textTheme.headlineMedium),
         Text(widget.activity.independentPrompt),
+        if (widget.state.aiProvider == AiProviderType.mock)
+          SectionCard(
+            tint: AppColors.warm,
+            child: const Text('尚未配置 AI 服务。本次可继续练习，但开放回答不会计入独立掌握。'),
+          ),
         if (widget.showHelp)
           SectionCard(
             tint: AppColors.warm,
@@ -255,19 +273,6 @@ class _IndependentStepState extends State<_IndependentStep>
               ),
             ),
           ),
-        OutlinedButton.icon(
-          onPressed: widget.canContinue && !checkingWithAi
-              ? _checkWithAi
-              : null,
-          icon: checkingWithAi
-              ? const SizedBox(
-                  width: 16,
-                  height: 16,
-                  child: CircularProgressIndicator(strokeWidth: 2),
-                )
-              : const Icon(Icons.spellcheck),
-          label: Text(checkingWithAi ? '正在检查…' : '提交前 AI 检查语法和拼写（可选）'),
-        ),
         if (aiCheck != null)
           SectionCard(
             tint: aiCheck!.verdict == 'accepted'
@@ -282,8 +287,10 @@ class _IndependentStepState extends State<_IndependentStep>
                   Text('参考改正：${aiCheck!.suggestion}'),
                 Text(
                   aiCheck!.verdict == 'accepted'
-                      ? 'AI 仅作参考；是否完成仍由本地检查判断。'
-                      : '看过改正后再提交，本次会记为带提示完成。',
+                      ? '本地目标与 AI 检查均通过。'
+                      : aiCheck!.verdict == 'rewrite'
+                      ? '修改后再次提交；看过改正，本次会记为辅助练习。'
+                      : '答案尚未核验，可重试或仅保存练习。',
                   style: TextStyle(fontSize: 12, color: AppColors.muted),
                 ),
               ],
@@ -322,9 +329,14 @@ class _IndependentStepState extends State<_IndependentStep>
         else
           TextButton(onPressed: widget.onLookup, child: const Text('查词或短语')),
         PrimaryButton(
-          label: widget.showHelp || aiCorrected ? '带帮助完成' : '独立完成',
-          onPressed: widget.canContinue ? _submit : null,
+          label: checkingWithAi ? '正在自动检查…' : '提交独立尝试',
+          onPressed: widget.canContinue && !checkingWithAi ? _submit : null,
         ),
+        if (aiCheckError != null)
+          TextButton(
+            onPressed: () => _finish(verified: false),
+            child: const Text('未核验，保存练习并继续'),
+          ),
         TextButton(onPressed: widget.onLater, child: const Text('稍后继续')),
       ],
     ),