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/writing_step.dart

@@ -34,23 +34,18 @@ class _WritingStepState extends State<_WritingStep> {
   String? aiFeedbackError;
   bool requestingAiFeedback = false;
 
-  void _checkOrContinue() {
-    if (result?.complete == true) {
-      widget.onContinue(aiFeedback != null);
-      return;
-    }
-    setState(
-      () => result = WritingFeedback.check(
-        widget.segmentId,
-        widget.controller.text,
-      ),
-    );
-  }
-
-  Future<void> _requestAiFeedback() async {
-    if (widget.controller.text.trim().isEmpty || requestingAiFeedback) return;
+  Future<void> _submit() async {
+    if (!widget.canContinue || requestingAiFeedback) return;
+    final answer = widget.controller.text.trim();
+    final local = WritingFeedback.check(widget.segmentId, answer);
+    setState(() {
+      result = local;
+      aiFeedback = null;
+      aiFeedbackError = null;
+    });
+    if (!local.complete) return;
     if (widget.state.aiProvider == AiProviderType.mock) {
-      setState(() => aiFeedbackError = '请先在“我的”配置 AI 服务；本地检查仍可继续学习。');
+      widget.onContinue(false);
       return;
     }
     setState(() {
@@ -64,19 +59,28 @@ class _WritingStepState extends State<_WritingStep> {
           model: widget.state.aiModel,
           lessonId: widget.lessonId,
           taskPrompt: widget.activity.writingPrompt,
-          answer: widget.controller.text.trim(),
+          answer: answer,
           level: lessonLevel(widget.lessonId),
         );
-    if (!mounted) return;
+    if (!mounted || widget.controller.text.trim() != answer) {
+      if (mounted) setState(() => requestingAiFeedback = false);
+      return;
+    }
+    if (feedback?.verdict == 'accepted') {
+      widget.onContinue(true);
+      return;
+    }
     setState(() {
       requestingAiFeedback = false;
       aiFeedback = feedback;
-      aiFeedbackError = feedback == null
-          ? '暂时无法获得 AI 反馈。你的答案保留在这里，可稍后重试或继续本地练习。'
+      aiFeedbackError = feedback == null || feedback.verdict == 'uncertain'
+          ? '答案暂时无法核验。可以重试，或仅保存这次练习继续学习。'
           : null;
     });
   }
 
+  void _continueUnverified() => widget.onContinue(false);
+
   @override
   Widget build(BuildContext context) => _LessonScaffold(
     step: 5,
@@ -87,6 +91,11 @@ class _WritingStepState extends State<_WritingStep> {
           widget.activity.writingPrompt,
           style: Theme.of(context).textTheme.headlineMedium,
         ),
+        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。'),
+          ),
         SectionCard(
           tint: AppColors.surfaceMuted,
           child: Text('小提示：${grammarNoteForSegment(widget.segmentId)}'),
@@ -126,19 +135,6 @@ class _WritingStepState extends State<_WritingStep> {
           onPressed: widget.onToggleHelp,
           child: Text(widget.showHelp ? '收起示例，自己试一次' : '需要帮助，查看示例'),
         ),
-        OutlinedButton.icon(
-          onPressed: widget.canContinue && !requestingAiFeedback
-              ? _requestAiFeedback
-              : null,
-          icon: requestingAiFeedback
-              ? const SizedBox(
-                  width: 16,
-                  height: 16,
-                  child: CircularProgressIndicator(strokeWidth: 2),
-                )
-              : const Icon(Icons.auto_awesome_outlined),
-          label: Text(requestingAiFeedback ? '正在获取反馈…' : '获取 AI 写作建议（可选）'),
-        ),
         if (aiFeedback != null)
           SectionCard(
             tint: aiFeedback!.verdict == 'accepted'
@@ -153,7 +149,9 @@ class _WritingStepState extends State<_WritingStep> {
                 if (aiFeedback!.suggestion != null)
                   Text('可参考改写：${aiFeedback!.suggestion}'),
                 Text(
-                  '这是学习帮助；请按自己的意思重写后再检查，系统不会仅凭 AI 建议记为掌握。',
+                  aiFeedback!.verdict == 'rewrite'
+                      ? '请按自己的意思修改，再提交检查。看过改正后，本次只算辅助练习。'
+                      : '答案尚未核验；可以重试检查或仅保存练习。',
                   style: TextStyle(fontSize: 12, color: AppColors.muted),
                 ),
               ],
@@ -167,20 +165,25 @@ class _WritingStepState extends State<_WritingStep> {
               style: TextStyle(color: AppColors.warmInk),
             ),
           ),
-        if (result != null)
+        if (result != null && !result!.complete)
           SectionCard(
-            tint: result!.complete ? AppColors.softGreen : AppColors.warm,
+            tint: AppColors.warm,
             child: Text(
               result!.message,
-              style: TextStyle(
-                color: result!.complete ? AppColors.green : AppColors.warmInk,
-              ),
+              style: TextStyle(color: AppColors.warmInk),
             ),
           ),
         PrimaryButton(
-          label: result?.complete == true ? '进入课程对话' : '检查句子',
-          onPressed: widget.canContinue ? _checkOrContinue : null,
+          label: requestingAiFeedback ? '正在自动检查…' : '提交并继续',
+          onPressed: widget.canContinue && !requestingAiFeedback
+              ? _submit
+              : null,
         ),
+        if (aiFeedbackError != null)
+          TextButton(
+            onPressed: _continueUnverified,
+            child: const Text('未核验，保存练习并继续'),
+          ),
       ],
     ),
   );