ai_english/client/lib/features/speaking/providers/speaking_provider.dart

import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../models/speaking_scenario.dart';
import '../models/conversation.dart';
import '../services/speaking_service.dart';

/// 口语任务状态
class SpeakingTasksState {
  final List<SpeakingTask> tasks;
  final bool isLoading;
  final String? error;

  SpeakingTasksState({
    this.tasks = const [],
    this.isLoading = false,
    this.error,
  });

  SpeakingTasksState copyWith({
    List<SpeakingTask>? tasks,
    bool? isLoading,
    String? error,
  }) {
    return SpeakingTasksState(
      tasks: tasks ?? this.tasks,
      isLoading: isLoading ?? this.isLoading,
      error: error,
    );
  }
}

/// 口语任务 Notifier
class SpeakingTasksNotifier extends StateNotifier<SpeakingTasksState> {
  final SpeakingService _speakingService;

  SpeakingTasksNotifier(this._speakingService) : super(SpeakingTasksState());

  /// 加载口语场景列表
  Future<void> loadScenarios({
    SpeakingScenario? scenario,
    SpeakingDifficulty? difficulty,
    int page = 1,
  }) async {
    state = state.copyWith(isLoading: true, error: null);
    
    try {
      final response = await _speakingService.getSpeakingScenarios(
        scenario: scenario,
        difficulty: difficulty,
        page: page,
      );
      
      if (response.success && response.data != null) {
        state = state.copyWith(tasks: response.data!, isLoading: false);
      } else {
        state = state.copyWith(
          isLoading: false,
          error: response.message,
        );
      }
    } catch (e) {
      state = state.copyWith(
        isLoading: false,
        error: e.toString(),
      );
    }
  }

  /// 获取推荐任务
  Future<void> loadRecommendedTasks() async {
    state = state.copyWith(isLoading: true, error: null);
    
    try {
      final response = await _speakingService.getRecommendedTasks();
      
      if (response.success && response.data != null) {
        state = state.copyWith(tasks: response.data!, isLoading: false);
      } else {
        state = state.copyWith(
          isLoading: false,
          error: response.message,
        );
      }
    } catch (e) {
      state = state.copyWith(
        isLoading: false,
        error: e.toString(),
      );
    }
  }
}

/// 口语服务 Provider
final speakingServiceProvider = Provider<SpeakingService>((ref) {
  return SpeakingService();
});

/// 口语任务列表 Provider
final speakingTasksProvider = StateNotifierProvider<SpeakingTasksNotifier, SpeakingTasksState>((ref) {
  final service = ref.watch(speakingServiceProvider);
  return SpeakingTasksNotifier(service);
});

/// 推荐口语任务 Provider
final recommendedSpeakingTasksProvider = FutureProvider<List<SpeakingTask>>((ref) async {
  final service = ref.watch(speakingServiceProvider);
  
  try {
    final response = await service.getRecommendedTasks();
    return response.data ?? [];
  } catch (e) {
    return [];
  }
});

/// 用户口语历史 Provider
final userSpeakingHistoryProvider = FutureProvider<List<Conversation>>((ref) async {
  final service = ref.watch(speakingServiceProvider);
  
  try {
    final response = await service.getUserSpeakingHistory(limit: 5);
    return response.data ?? [];
  } catch (e) {
    return [];
  }
});