import 'package:flutter/widgets.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:fruitshorts/core/config/locale_controller.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:shared_preferences_platform_interface/in_memory_shared_preferences_async.dart';
import 'package:shared_preferences_platform_interface/shared_preferences_async_platform_interface.dart';

void main() {
  setUp(() {
    SharedPreferencesAsyncPlatform.instance =
        InMemorySharedPreferencesAsync.empty();
  });

  test('should_keep_device_locale_when_no_choice_is_stored', () async {
    final controller = LocaleController();
    var notifications = 0;
    controller.addListener(() => notifications++);

    await controller.load();

    expect(controller.locale, isNull);
    expect(notifications, 1);
  });

  test('should_restore_chosen_language_when_app_restarts', () async {
    final first = LocaleController();
    await first.select('zh');
    expect(first.locale, const Locale('zh'));

    final reopened = LocaleController();
    await reopened.load();
    expect(reopened.locale, const Locale('zh'));
  });

  test('should_restore_indonesian_when_selected_and_app_restarts', () async {
    final first = LocaleController();
    await first.select('id');
    expect(first.locale, const Locale('id'));

    final reopened = LocaleController();
    await reopened.load();
    expect(reopened.locale, const Locale('id'));
  });

  test('should_fallback_to_indonesian_when_system_language_is_unsupported', () {
    expect(resolveAppLocale(null, const Locale('en')), const Locale('en'));
    expect(resolveAppLocale(null, const Locale('id')), const Locale('id'));
    expect(resolveAppLocale(null, const Locale('fr')), const Locale('id'));
    expect(resolveAppLocale(null, const Locale('in')), const Locale('id'));
    expect(
      resolveAppLocale(const Locale('zh'), const Locale('fr')),
      const Locale('zh'),
    );
  });

  test(
    'should_clear_stored_chinese_preference_when_english_is_selected',
    () async {
      await LocaleController().select('zh');

      final reopened = LocaleController();
      await reopened.load();
      await reopened.select('en');

      final third = LocaleController();
      await third.load();
      expect(third.locale, const Locale('en'));
    },
  );

  test('should_clear_locale_when_code_is_unsupported', () async {
    final controller = LocaleController();
    await controller.select('zh');
    expect(controller.locale, const Locale('zh'));

    await controller.select('tlh');

    expect(controller.locale, isNull);
  });

  test(
    'should_resolve_to_device_locale_when_stored_code_is_unsupported',
    () async {
      await SharedPreferencesAsync().setString('ui.locale', 'fr');

      final controller = LocaleController();
      await controller.load();

      expect(controller.locale, isNull);
    },
  );

  test(
    'should_survive_load_and_select_when_preference_store_is_broken',
    () async {
      SharedPreferencesAsyncPlatform.instance = _BrokenPreferences();
      final controller = LocaleController();

      await controller.load();
      expect(controller.locale, isNull);

      await controller.select('zh');
      expect(controller.locale, const Locale('zh'));
    },
  );
}

/// Stands in for a platform whose preference store is unavailable.
base class _BrokenPreferences extends InMemorySharedPreferencesAsync {
  _BrokenPreferences() : super.empty();

  @override
  Future<String?> getString(String key, SharedPreferencesOptions options) =>
      Future<String?>.error(StateError('preferences unavailable'));

  @override
  Future<bool> setString(
    String key,
    String value,
    SharedPreferencesOptions options,
  ) => Future<bool>.error(StateError('preferences unavailable'));
}