flutter-core-modules: Skill for Claude Code

Feature: Locale

Purpose: Persist and restore the user's chosen Locale across app sessions using SharedPreferences. The feature has no UI — it is a pure data/domain module.

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Layer Map

lib/src/features/locale/
├── domain/
│   ├── repositories/locale_repository.dart      # abstract LocaleRepository
│   └── usecases/
│       ├── get_locale_usecase.dart               # GetLocaleUsecase + provider
│       ├── set_locale_usecase.dart               # SetLocaleUsecase + provider
│       └── remove_locale_usecase.dart            # RemoveLocaleUsecase + provider
└── data/
    └── repositories/locale_repository.dart      # LocaleRepositoryImpl + provider

No presentation/ layer — locale is consumed directly via use cases.

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Domain

Repository Interface

// lib/src/features/locale/domain/repositories/locale_repository.dart
abstract class LocaleRepository {
  Locale? getLocale();                               // sync, nullable
  Future<bool> setLocale({required Locale locale});  // returns success bool
  Future<bool> removeLocale();                       // returns success bool
}

Use Cases

Class	Provider	Signature
GetLocaleUsecase	getLocaleUsecaseProvider	Locale? call()
SetLocaleUsecase	setLocaleUsecaseProvider	Future<bool> call({required Locale locale})
RemoveLocaleUsecase	removeLocaleUsecaseProvider	Future<bool> call()

All providers are Provider.autoDispose.

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Data

LocaleRepositoryImpl

File: lib/src/features/locale/data/repositories/locale_repository.dart

Persists locale as a List<String> in SharedPreferences:

• Key: DatabaseKeys.locale.key → 'locale' (prod) / 'localeDebug' (debug)
• Stored value: ['en'] or ['en', 'US'] (languageCode + optional countryCode)
• Reads back: pattern matches on the list length to reconstruct Locale

// Storage format:
// Locale('en')       → ['en']
// Locale('pt', 'BR') → ['pt', 'BR']

final localeRepositoryProvider = Provider.autoDispose<LocaleRepository>(
  (ref) => LocaleRepositoryImpl(
    sharedPreferences: ref.read(sharedPreferencesProvider),
  ),
);