japp_flutter/lib/features/challenge/view_models/challenge_add_vm.dart

// features/challenge/add/add_challenge_viewmodel.dart
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:japp_flutter/core/models/challenge_model.dart';
import 'package:japp_flutter/core/proviers/repository_providers.dart';
import 'package:japp_flutter/core/repositories/challenge_repository.dart';

final addChallengeProvider =
    AsyncNotifierProvider<AddChallengeViewModel, ChallengeModel>(
      AddChallengeViewModel.new,
    );

class AddChallengeViewModel extends AsyncNotifier<ChallengeModel> {
  ChallengeRepository get _repository => ref.read(challengeRepositoryProvider);

  @override
  Future<ChallengeModel> build() async {
    // 初始化为空挑战模板
    return ChallengeModel(
      id: null,
      title: '',
      description: '',
      startDate: DateTime.now(),
      endDate: DateTime.now().add(const Duration(days: 30)),
      actionType: 1,
      cover: '',
      sort: 200,
      status: 1,
      difficulty: 1,
      remark: '',
      finishDate: null,
      parentId: 1,
      planFinishDate: null
    );
  }

  /// 更新挑战标题
  void updateTitle(String title) {
    state = AsyncData(state.value!.copyWith(title: title));
  }

  /// 更新挑战描述
  void updateDescription(String description) {
    state = AsyncData(state.value!.copyWith(description: description));
  }

  /// 更新难度级别
  void updateDifficulty(int difficulty) {
    state = AsyncData(state.value!.copyWith(difficulty: difficulty));
  }

  /// 更新日期范围
  void updateDateRange(DateTime start, DateTime end) {
    state = AsyncData(state.value!.copyWith(startDate: start, endDate: end));
  }

  /// 提交新挑战
  Future<void> submitChallenge() async {
    if (state.value == null) return;

    state = const AsyncLoading();
    state = await AsyncValue.guard(
      () => _repository.addChallenge(state.value!),
    );
  }
}