feat(app): 班级码验证前后端联调 — AuthBloc接入API + 错误计数锁定UI

app/lib/app.dart

@@ -46,7 +46,10 @@ class NuanjiApp extends StatelessWidget {
     final syncEngine = SyncEngine(apiClient: apiClient);
     final classRepository = ClassRepository(api: apiClient);
     final settingsBloc = SettingsBloc();
-    final authBloc = AuthBloc(authRepository: authRepository);
+    final authBloc = AuthBloc(
+      authRepository: authRepository,
+      classRepository: classRepository,
+    );
 
     // 启动时检查认证状态
     authBloc.add(const AppStarted());

app/lib/features/auth/bloc/auth_bloc.dart

@@ -4,6 +4,7 @@
 //                                     ↕
 //                                  Authenticating → Authenticated/AuthError
 
+import 'package:dio/dio.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:logger/logger.dart';
 
@@ -11,6 +12,7 @@ import '../../../data/models/auth_token.dart';
 import '../../../data/models/user.dart';
 import '../../../data/remote/api_client.dart';
 import '../../../data/repositories/auth_repository.dart';
+import '../../../data/repositories/class_repository.dart';
 
 part 'auth_event.dart';
 part 'auth_state.dart';
@@ -18,10 +20,14 @@ part 'auth_state.dart';
 /// 认证 BLoC — 处理所有认证相关的状态转换
 class AuthBloc extends Bloc<AuthEvent, AuthState> {
   final AuthRepository _authRepository;
+  final ClassRepository? _classRepository;
   final Logger _logger = Logger(printer: PrettyPrinter(methodCount: 0));
 
-  AuthBloc({required AuthRepository authRepository})
+  AuthBloc({
-      : _authRepository = authRepository,
+    required AuthRepository authRepository,
+    ClassRepository? classRepository,
+  })  : _authRepository = authRepository,
+        _classRepository = classRepository,
         super(const AuthInitial()) {
     // 注册事件处理器
     on<AppStarted>(_onAppStarted);
@@ -138,13 +144,64 @@ class AuthBloc extends Bloc<AuthEvent, AuthState> {
     final currentState = state;
     if (currentState is! Authenticated) return;
 
-    // TODO: 调用后端 API 验证班级码并加入班级
+    // 如果没有 ClassRepository（离线模式），直接跳过
-    // 当前先标记为已完成，班级码验证在 F8 阶段完善
+    final classRepo = _classRepository;
-    emit(currentState.copyWith(
+    if (classRepo == null) {
-      needsClassCode: false,
+      _logger.w('ClassRepository 不可用，跳过班级码验证');
-    ));
+      emit(currentState.copyWith(needsClassCode: false));
+      return;
+    }
 
-    _logger.i('班级码加入: ${event.classCode}');
+    emit(currentState.copyWith(isLoading: true));
+
+    try {
+      // 调用后端 API 验证班级码并加入班级
+      await classRepo.joinClass(
+        event.classCode,
+        nickname: currentState.user.displayName,
+      );
+
+      // 成功 — 清除班级码需求
+      emit(currentState.copyWith(
+        needsClassCode: false,
+        isLoading: false,
+      ));
+
+      _logger.i('班级码加入成功: ${event.classCode}');
+    } on DioException catch (e) {
+      final statusCode = e.response?.statusCode;
+      String errorMessage = '加入班级失败，请重试';
+
+      if (statusCode == 400) {
+        // 班级码无效或已过期
+        final body = e.response?.data;
+        if (body is Map && body['message'] is String) {
+          errorMessage = body['message'] as String;
+        } else {
+          errorMessage = '班级码无效，请检查后重新输入';
+        }
+      } else if (statusCode == 429) {
+        // 尝试次数过多 — 锁定
+        errorMessage = '尝试次数过多，请等待 30 分钟后再试';
+      }
+
+      _logger.w('班级码验证失败 ($statusCode): $errorMessage');
+      emit(currentState.copyWith(
+        isLoading: false,
+        classCodeError: errorMessage,
+      ));
+    } on OfflineException {
+      emit(currentState.copyWith(
+        isLoading: false,
+        classCodeError: '网络不可用，请检查网络后重试',
+      ));
+    } catch (e) {
+      _logger.e('班级码验证异常: $e');
+      emit(currentState.copyWith(
+        isLoading: false,
+        classCodeError: '加入班级失败，请稍后重试',
+      ));
+    }
   }
 
   /// 用户登出

app/lib/features/auth/bloc/auth_state.dart

@@ -40,21 +40,33 @@ final class Authenticated extends AuthState {
   /// 是否需要班级码加入（学生/家长角色）
   final bool needsClassCode;
 
+  /// 是否正在加载（班级码验证中）
+  final bool isLoading;
+
+  /// 班级码验证错误信息
+  final String? classCodeError;
+
   const Authenticated({
     required this.user,
     this.needsRoleSelection = false,
     this.needsClassCode = false,
+    this.isLoading = false,
+    this.classCodeError,
   });
 
   Authenticated copyWith({
     User? user,
     bool? needsRoleSelection,
     bool? needsClassCode,
+    bool? isLoading,
+    String? classCodeError,
   }) =>
       Authenticated(
         user: user ?? this.user,
         needsRoleSelection: needsRoleSelection ?? this.needsRoleSelection,
         needsClassCode: needsClassCode ?? this.needsClassCode,
+        isLoading: isLoading ?? this.isLoading,
+        classCodeError: classCodeError,
       );
 }
 

app/lib/features/auth/views/class_code_join_page.dart

@@ -31,6 +31,19 @@ class _ClassCodeJoinPageState extends State<ClassCodeJoinPage> {
     (_) => FocusNode(),
   );
 
+  int _failedAttempts = 0;
+  DateTime? _lockoutEndTime;
+
+  /// 当前是否被锁定
+  bool get _isCurrentlyLocked {
+    if (_lockoutEndTime == null) return false;
+    if (DateTime.now().isAfter(_lockoutEndTime!)) {
+      _lockoutEndTime = null;
+      return false;
+    }
+    return true;
+  }
+
   @override
   void initState() {
     super.initState();
@@ -58,6 +71,14 @@ class _ClassCodeJoinPageState extends State<ClassCodeJoinPage> {
   bool get _isComplete =>
       _controllers.every((c) => c.text.isNotEmpty);
 
+  /// 清空所有输入框
+  void _clearInputs() {
+    for (final c in _controllers) {
+      c.clear();
+    }
+    _focusNodes[0].requestFocus();
+  }
+
   void _onChanged(int index, String value) {
     if (value.isEmpty && index > 0) {
       // 退格清空 → 跳到前一位
@@ -74,13 +95,48 @@ class _ClassCodeJoinPageState extends State<ClassCodeJoinPage> {
   }
 
   void _submit() {
-    if (!_isComplete) return;
+    if (!_isComplete || _isCurrentlyLocked) return;
     context.read<AuthBloc>().add(ClassCodeSubmitted(_classCode));
+  }
 
-    // 提交后跳转到首页（班级码验证由 BLoC 处理）
+  /// 处理 AuthBloc 状态变化
-    final state = context.read<AuthBloc>().state;
+  void _handleAuthState(BuildContext context, AuthState state) {
-    if (state is Authenticated && !state.needsClassCode) {
+    if (state is! Authenticated) return;
+
+    // 成功加入班级
+    if (!state.needsClassCode) {
       context.go('/home');
+      return;
+    }
+
+    // 班级码验证错误
+    final error = state.classCodeError;
+    if (error != null && error.isNotEmpty) {
+      _failedAttempts++;
+
+      // 检查是否为锁定错误
+      if (error.contains('30 分钟') || error.contains('尝试次数过多')) {
+        setState(() {
+          _lockoutEndTime = DateTime.now().add(
+            Duration(minutes: DesignTokens.classCodeLockoutMinutes),
+          );
+        });
+      }
+
+      // 清空输入
+      _clearInputs();
+
+      // 显示错误提示
+      if (mounted) {
+        ScaffoldMessenger.of(context).clearSnackBars();
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(
+            content: Text(error),
+            backgroundColor: Theme.of(context).colorScheme.error,
+            duration: const Duration(seconds: 3),
+          ),
+        );
+      }
     }
   }
 
@@ -88,75 +144,136 @@ class _ClassCodeJoinPageState extends State<ClassCodeJoinPage> {
   Widget build(BuildContext context) {
     final colorScheme = Theme.of(context).colorScheme;
 
-    return Scaffold(
+    return BlocListener<AuthBloc, AuthState>(
-      body: SafeArea(
+      listener: _handleAuthState,
-        child: Padding(
+      child: Scaffold(
-          padding: const EdgeInsets.symmetric(
+        body: SafeArea(
-            horizontal: DesignTokens.spacing24,
+          child: Padding(
-          ),
+            padding: const EdgeInsets.symmetric(
-          child: Column(
+              horizontal: DesignTokens.spacing24,
-            children: [
+            ),
-              const Spacer(flex: 2),
+            child: Column(
+              children: [
+                const Spacer(flex: 2),
 
-              // 标题
+                // 标题
-              Icon(
+                Icon(
-                Icons.groups_rounded,
+                  Icons.groups_rounded,
-                size: 64,
+                  size: 64,
-                color: colorScheme.primary,
+                  color: colorScheme.primary,
-              ),
-              const SizedBox(height: DesignTokens.spacing24),
-              Text(
-                '加入班级',
-                style: Theme.of(context).textTheme.headlineMedium?.copyWith(
-                      fontWeight: FontWeight.bold,
-                    ),
-              ),
-              const SizedBox(height: DesignTokens.spacing8),
-              Text(
-                '输入老师提供的 6 位班级码',
-                style: Theme.of(context).textTheme.bodyLarge?.copyWith(
-                      color: colorScheme.onSurface.withValues(alpha: 0.6),
-                    ),
-              ),
-              const SizedBox(height: DesignTokens.spacing48),
-
-              // 6 位输入框
-              Row(
-                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-                children: List.generate(
-                  DesignTokens.classCodeLength,
-                  (index) => _buildCodeInput(context, index, colorScheme),
                 ),
-              ),
+                const SizedBox(height: DesignTokens.spacing24),
-              const SizedBox(height: DesignTokens.spacing24),
+                Text(
+                  '加入班级',
+                  style: Theme.of(context).textTheme.headlineMedium?.copyWith(
+                        fontWeight: FontWeight.bold,
+                      ),
+                ),
+                const SizedBox(height: DesignTokens.spacing8),
+                Text(
+                  '输入老师提供的 6 位班级码',
+                  style: Theme.of(context).textTheme.bodyLarge?.copyWith(
+                        color: colorScheme.onSurface.withValues(alpha: 0.6),
+                      ),
+                ),
+                const SizedBox(height: DesignTokens.spacing48),
 
-              // 跳过按钮
+                // 锁定状态 or 输入框
-              TextButton(
+                if (_isCurrentlyLocked)
-                onPressed: () => context.go('/home'),
+                  _buildLockoutView(context, colorScheme)
-                child: Text(
+                else
-                  '稍后再加入',
+                  _buildCodeInputs(context, colorScheme),
-                  style: TextStyle(
+
-                    color: colorScheme.onSurface.withValues(alpha: 0.5),
+                const SizedBox(height: DesignTokens.spacing24),
+
+                // 跳过按钮
+                TextButton(
+                  onPressed: () => context.go('/home'),
+                  child: Text(
+                    '稍后再加入',
+                    style: TextStyle(
+                      color: colorScheme.onSurface.withValues(alpha: 0.5),
+                    ),
                   ),
                 ),
-              ),
 
-              const Spacer(flex: 3),
+                // 剩余尝试次数提示
-            ],
+                if (!_isCurrentlyLocked && _failedAttempts > 0)
+                  Padding(
+                    padding: const EdgeInsets.only(top: 8),
+                    child: Text(
+                      '剩余 ${DesignTokens.classCodeMaxAttempts - _failedAttempts} 次尝试机会',
+                      style: Theme.of(context).textTheme.bodySmall?.copyWith(
+                            color: _failedAttempts >= 4
+                                ? colorScheme.error
+                                : colorScheme.onSurface.withValues(alpha: 0.5),
+                          ),
+                    ),
+                  ),
+
+                const Spacer(flex: 3),
+              ],
+            ),
           ),
         ),
       ),
     );
   }
 
+  /// 锁定视图 — 超过最大尝试次数后显示
+  Widget _buildLockoutView(BuildContext context, ColorScheme colorScheme) {
+    return Column(
+      children: [
+        Icon(Icons.lock_outline, size: 48, color: colorScheme.error),
+        const SizedBox(height: 16),
+        Text(
+          '尝试次数过多',
+          style: Theme.of(context).textTheme.titleMedium?.copyWith(
+                fontWeight: FontWeight.bold,
+              ),
+        ),
+        const SizedBox(height: 8),
+        Text(
+          '请等待 ${DesignTokens.classCodeLockoutMinutes} 分钟后再试',
+          style: Theme.of(context).textTheme.bodyMedium?.copyWith(
+                color: colorScheme.onSurface.withValues(alpha: 0.6),
+              ),
+        ),
+      ],
+    );
+  }
+
+  /// 6 位班级码输入框
+  Widget _buildCodeInputs(BuildContext context, ColorScheme colorScheme) {
+    return BlocBuilder<AuthBloc, AuthState>(
+      builder: (context, state) {
+        final isLoading = state is Authenticated && state.isLoading;
+
+        return Row(
+          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+          children: List.generate(
+            DesignTokens.classCodeLength,
+            (index) => _buildCodeInput(context, index, colorScheme, isLoading),
+          ),
+        );
+      },
+    );
+  }
+
   /// 单个班级码输入框
-  Widget _buildCodeInput(BuildContext context, int index, ColorScheme colorScheme) {
+  Widget _buildCodeInput(
+    BuildContext context,
+    int index,
+    ColorScheme colorScheme,
+    bool isLoading,
+  ) {
     return SizedBox(
       width: 48,
       height: 56,
       child: TextField(
         controller: _controllers[index],
         focusNode: _focusNodes[index],
+        enabled: !isLoading,
         textAlign: TextAlign.center,
         textAlignVertical: TextAlignVertical.center,
         style: Theme.of(context).textTheme.headlineSmall?.copyWith(

app/lib/features/auth/views/login_page.dart

@@ -11,6 +11,7 @@ import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:go_router/go_router.dart';
 
 import '../../../core/constants/design_tokens.dart';
+import '../../../core/theme/app_radius.dart';
 import '../bloc/auth_bloc.dart';
 
 /// 登录/注册页面
@@ -138,7 +139,7 @@ class _LoginPageState extends State<LoginPage> with SingleTickerProviderStateMix
           height: 80,
           decoration: BoxDecoration(
             color: colorScheme.primaryContainer,
-            borderRadius: BorderRadius.circular(22),
+            borderRadius: AppRadius.lgBorder,
           ),
           child: Icon(
             Icons.edit_note_rounded,
@@ -186,7 +187,7 @@ class _LoginPageState extends State<LoginPage> with SingleTickerProviderStateMix
                           hintText: '你想被叫什么名字？',
                           prefixIcon: const Icon(Icons.face_rounded),
                           border: OutlineInputBorder(
-                            borderRadius: BorderRadius.circular(16),
+                            borderRadius: AppRadius.mdBorder,
                           ),
                         ),
                         textInputAction: TextInputAction.next,
@@ -202,7 +203,7 @@ class _LoginPageState extends State<LoginPage> with SingleTickerProviderStateMix
               hintText: _isRegister ? '设置一个账号名' : '输入你的账号',
               prefixIcon: const Icon(Icons.person_rounded),
               border: OutlineInputBorder(
-                borderRadius: BorderRadius.circular(16),
+                borderRadius: AppRadius.mdBorder,
               ),
             ),
             textInputAction: TextInputAction.next,
@@ -237,7 +238,7 @@ class _LoginPageState extends State<LoginPage> with SingleTickerProviderStateMix
                 },
               ),
               border: OutlineInputBorder(
-                borderRadius: BorderRadius.circular(16),
+                borderRadius: AppRadius.mdBorder,
               ),
             ),
             textInputAction: TextInputAction.done,
@@ -268,7 +269,7 @@ class _LoginPageState extends State<LoginPage> with SingleTickerProviderStateMix
             onPressed: isLoading ? null : _submit,
             style: FilledButton.styleFrom(
               shape: RoundedRectangleBorder(
-                borderRadius: BorderRadius.circular(16),
+                borderRadius: AppRadius.mdBorder,
               ),
             ),
             child: isLoading

app/lib/features/auth/views/role_selection_page.dart

@@ -11,6 +11,7 @@ import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:go_router/go_router.dart';
 
 import '../../../core/constants/design_tokens.dart';
+import '../../../core/theme/app_radius.dart';
 import '../../../data/models/user.dart';
 import '../bloc/auth_bloc.dart';
 
@@ -146,11 +147,11 @@ class _RoleCardWidget extends StatelessWidget {
       color: Colors.transparent,
       child: InkWell(
         onTap: onTap,
-        borderRadius: BorderRadius.circular(22),
+        borderRadius: AppRadius.lgBorder,
         child: Ink(
           decoration: BoxDecoration(
             color: role.color.withValues(alpha: 0.12),
-            borderRadius: BorderRadius.circular(22),
+            borderRadius: AppRadius.lgBorder,
             border: Border.all(
               color: role.color.withValues(alpha: 0.3),
               width: 2,