# Implementation Plan: App启动时语言和时区自动设置

## Phase 1: 前端 - 读取系统语言/时区

### 1.1 创建系统Locale工具函数

**文件**: `apps/lib/app/locale_utils.dart` (新建)

**Locale映射规则** (基于项目现有约定):

| 系统Locale | Flutter Locale | 存储Tag |
|-----------|----------------|---------|
| en, en-US, en-GB, ... | `Locale('en')` | `en-US` |
| zh, zh-CN, zh-SG, zh-Hans-* | `Locale('zh')` | `zh-CN` |
| zh-Hant, zh-TW, zh-HK, zh-MO | `Locale.fromSubtags(languageCode: 'zh', scriptCode: 'Hant')` | `zh-Hant` |
| 其他 | null (回退默认) | `zh-CN` |

```dart
import 'dart:ui';
import 'package:flutter/material.dart';

/// 从系统Locale映射到App支持的Locale
/// 返回 null 表示不支持，调用方应使用默认值
Locale? resolveSystemLocale(Locale systemLocale) {
  final lang = systemLocale.languageCode.toLowerCase();
  final script = systemLocale.scriptCode;
  final country = systemLocale.countryCode;

  // 英文: en, en-US, en-GB, ... → Locale('en') → 存储 en-US
  if (lang == 'en') {
    return const Locale('en');
  }

  // 中文处理
  if (lang == 'zh') {
    // 繁体: zh-Hant, zh-TW, zh-HK, zh-MO → Locale(zh, Hant) → 存储 zh-Hant
    if (script == 'Hant' || country == 'TW' || country == 'HK' || country == 'MO') {
      return const Locale.fromSubtags(languageCode: 'zh', scriptCode: 'Hant');
    }
    // 简体: zh, zh-CN, zh-SG, zh-Hans-* → Locale('zh') → 存储 zh-CN
    return const Locale('zh');
  }

  // 其他语言不支持，回退到默认
  return null;
}

/// 获取系统首选Locale
Locale getSystemLocale() {
  return PlatformDispatcher.instance.locale;
}
```

### 1.2 创建系统时区工具函数

**文件**: `apps/lib/app/timezone_utils.dart` (新建)

**方案选择**:
- 方案1: 使用 `flutter_timezone` 包 (推荐，直接返回IANA ID)
- 方案2: 使用 `DateTime.now().timeZoneName` + 映射表 (无额外依赖，但需维护映射)

```dart
import 'package:flutter_timezone/flutter_timezone.dart';

/// 获取系统时区IANA ID
/// 例如: Asia/Shanghai, America/New_York, Europe/London
Future<String> getSystemTimezone() async {
  try {
    final timezone = await FlutterTimezone.getLocalTimezone();
    // 验证是否为有效IANA ID
    if (timezone.isNotEmpty) {
      return timezone;
    }
  } catch (_) {
    // ignore
  }
  // 回退到默认
  return 'Asia/Shanghai';
}
```

**依赖添加** (`apps/pubspec.yaml`):
```yaml
dependencies:
  flutter_timezone: ^3.0.1
```

### 1.3 扩展SessionStore

**文件**: `apps/lib/core/auth/session_store.dart`

```dart
// 新增
static const String _timezoneKey = 'selected_timezone';

Future<void> saveTimezone(String timezone) async {
  await _kvStore.setString(_timezoneKey, timezone);
}

Future<String?> getTimezone() async {
  return _kvStore.getString(_timezoneKey);
}
```

### 1.4 修改App启动流程

**文件**: `apps/lib/app/app.dart`

**步骤1**: 添加 `_timezone` 状态变量声明

```dart
// 在 State 类顶部添加
String _timezone = 'Asia/Shanghai';
```

**步骤2**: 修改 `_bootstrap()` 方法
```dart
Future<void> _bootstrap() async {
  // 1. 语言处理
  final savedLocaleTag = await _sessionStore.getLocaleTag();
  final Locale locale;
  if (savedLocaleTag != null) {
    locale = localeFromLanguageTag(savedLocaleTag);
  } else {
    final systemLocale = getSystemLocale();
    locale = resolveSystemLocale(systemLocale) ?? const Locale('zh');
    await _sessionStore.saveLocaleTag(languageTagFromLocale(locale));
  }
  
  // 2. 时区处理
  final savedTimezone = await _sessionStore.getTimezone();
  final String timezone;
  if (savedTimezone != null) {
    timezone = savedTimezone;
  } else {
    timezone = await getSystemTimezone();
    await _sessionStore.saveTimezone(timezone);
  }
  
  // 3. 设置状态
  setState(() {
    _locale = locale;
    _timezone = timezone;
  });
  
  // 4. 启动认证
  await _authBloc.start();
}
```

---

## Phase 2: 前端 - 注册时传递语言/时区

### 2.1 扩展AuthApi

**文件**: `apps/lib/features/auth/data/apis/auth_api.dart`

```dart
Future<SessionResponse> createEmailSession({
  required String email,
  required String token,
  String? language,
  String? timezone,
}) async {
  final data = <String, dynamic>{
    'email': email,
    'token': token,
  };
  if (language != null) data['language'] = language;
  if (timezone != null) data['timezone'] = timezone;
  
  final json = await _apiClient.postJson('/api/v1/auth/email-session', data: data);
  return SessionResponse.fromJson(json);
}
```

### 2.2 扩展AuthRepository

**文件**: `apps/lib/features/auth/data/repositories/auth_repository.dart`

```dart
// 接口定义
abstract class AuthRepository {
  // ... 现有方法 ...
  Future<User> loginWithEmailOtp({
    required String email,
    required String otp,
    String? language,
    String? timezone,
  });
}

// 实现
class AuthRepositoryImpl implements AuthRepository {
  // ... 现有代码 ...
  
  @override
  Future<User> loginWithEmailOtp({
    required String email,
    required String otp,
    String? language,
    String? timezone,
  }) async {
    final response = await _authApi.createEmailSession(
      email: email,
      token: otp,
      language: language,
      timezone: timezone,
    );
    // ... 现有的 session 处理逻辑 ...
  }
}
```

### 2.3 扩展AuthBloc

**文件**: `apps/lib/features/auth/presentation/bloc/auth_bloc.dart`

```dart
Future<void> loginWithOtp({
  required String email,
  required String otp,
  String? language,
  String? timezone,
}) async {
  final user = await _repository.loginWithEmailOtp(
    email: email,
    otp: otp,
    language: language,
    timezone: timezone,
  );
  // ...
}
```

### 2.4 修改App调用点

**文件**: `apps/lib/app/app.dart`

```dart
// LoginScreen 的 onLoginWithOtp 回调
onLoginWithOtp: (email, otp) {
  return _authBloc.loginWithOtp(
    email: email,
    otp: otp,
    language: languageTagFromLocale(_locale),
    timezone: _timezone,
  );
},
```

---

## Phase 3: 后端 - 接收语言/时区

### 3.1 扩展Schema

**文件**: `backend/src/v1/auth/schemas.py`

```python
class EmailSessionCreateRequest(BaseModel):
    model_config = ConfigDict(extra="forbid")

    email: str = Field(pattern=SUPABASE_EMAIL_PATTERN)
    token: str = Field(min_length=6, max_length=6)
    language: str | None = Field(default=None, max_length=20)
    timezone: str | None = Field(default=None, max_length=50)
```

### 3.2 扩展AuthService

**文件**: `backend/src/v1/auth/service.py`

```python
async def create_email_session(
    self, 
    payload: EmailSessionCreateRequest,
) -> SessionResponse:
    # ... 现有的 session 创建逻辑 ...
    
    # 如果提供了语言/时区，更新Profile
    if payload.language or payload.timezone:
        await self._update_profile_preferences(
            user_id=user.id,
            language=payload.language,
            timezone=payload.timezone,
        )
    
    return result

async def _update_profile_preferences(
    self,
    user_id: UUID,
    language: str | None,
    timezone: str | None,
) -> None:
    """更新用户Profile的语言/时区偏好设置"""
    profile = await self.profile_repository.get_profile_by_user_id(user_id)
    if profile is None:
        return
    
    settings = profile.settings or {}
    preferences = settings.get("preferences", {})
    
    if language is not None:
        preferences["language"] = language
    if timezone is not None:
        preferences["timezone"] = timezone
    
    settings["preferences"] = preferences
    profile.settings = settings
    
    await self.profile_repository.save()
```

### 3.3 AuthService依赖注入

**文件**: `backend/src/v1/auth/service.py`

AuthService 需要注入 `ProfileRepository` 或 `UserRepository` 以便更新 Profile。

```python
@dataclass
class AuthService:
    # ... 现有依赖 ...
    profile_repository: SQLAlchemyUserRepository  # 新增
```

**或**: 复用现有的 `v1/users/service.py` 中的 `UserService.update_settings()` 方法。

---

## Phase 4: 前端 - 登录后同步时区

### 4.1 修改_refreshProfile

**文件**: `apps/lib/app/app.dart`

```dart
Future<void> _refreshProfile({required String userEmail}) async {
  // ... 现有逻辑 ...
  
  final serverLanguage = profile.preferences.language;
  final serverTimezone = profile.preferences.timezone;
  
  // 同步语言
  await _sessionStore.saveLocaleTag(serverLanguage);
  
  // 同步时区
  await _sessionStore.saveTimezone(serverTimezone);
  
  setState(() {
    _locale = localeFromLanguageTag(serverLanguage);
    _timezone = serverTimezone;
    _profileSettings = profile;
    // ...
  });
}
```

---

## Phase 5: 验证和测试

### 5.1 单元测试

- [ ] `resolveSystemLocale` 映射正确性
- [ ] `getSystemTimezone` 返回有效IANA ID
- [ ] `SessionStore` 时区存取

### 5.2 集成测试

- [ ] 新设备首次打开 → 系统语言/时区生效
- [ ] 新用户注册 → 后端Profile正确
- [ ] 已有用户登录 → 服务器值同步
- [ ] 有本地存储 → 使用本地值

### 5.3 手动测试

- [ ] iOS系统语言设为英文 → App显示英文
- [ ] iOS系统语言设为繁体中文 → App显示繁体
- [ ] iOS系统时区设为非上海 → App时区正确

---

## 实施顺序

1. **Phase 1.3**: 扩展SessionStore（最小改动，无依赖）
2. **Phase 1.1-1.2**: 创建工具函数
3. **Phase 1.4**: 修改启动流程
4. **Phase 3.1**: 后端Schema扩展
5. **Phase 3.2-3.3**: 后端Service逻辑
6. **Phase 2**: 前端注册流程扩展
7. **Phase 4**: 登录后同步时区
8. **Phase 5**: 测试验证

---

## 依赖

- 可选: `flutter_timezone` 包（如需精确时区ID）
  - 添加到 `apps/pubspec.yaml`
  - 或使用 `DateTime.now().timeZoneName` + 映射表（无依赖）