xianyan/lib/l10n/app_locale.dart

/// ============================================================
/// 闲言APP — 应用语言枚举与Locale解析
/// 创建时间: 2026-05-19
/// 更新时间: 2026-05-31
/// 作用: 定义所有支持的语言，提供Locale解析/RTL检测/机器翻译标注/系统语言监听
/// 部分英文字段 可以硬编码 不需要翻译
/// 上次更新: 新增isMachineTranslated属性，覆盖率低于80%的语言标注为机器翻译
/// ============================================================

import 'package:flutter/widgets.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:intl/intl.dart' hide TextDirection;

import '../../features/mine/settings/providers/general_settings_provider.dart';

const _rtlLanguageCodes = {'ar', 'he', 'fa', 'ur'};

enum AppLocale {
  system('system', '跟随系统', 'Follow System', null, null, '🌐'),
  zhCN('zh_CN', '简体中文', 'Simplified Chinese', 'zh', 'CN', '🇨🇳'),
  en('en', 'English', 'English', 'en', null, '🇺🇸'),
  ja('ja', '日本語', 'Japanese', 'ja', null, '🇯🇵'),
  zhTW('zh_TW', '繁體中文', 'Traditional Chinese', 'zh', 'TW', '🇨🇳'),
  ko('ko', '한국어', 'Korean', 'ko', null, '🇰🇷'),
  de('de', 'Deutsch', 'German', 'de', null, '🇩🇪'),
  it('it', 'Italiano', 'Italian', 'it', null, '🇮🇹'),
  es('es', 'Español', 'Spanish', 'es', null, '🇪🇸'),
  ar('ar', 'العربية', 'Arabic', 'ar', null, '🇸🇦'),
  bn('bn', 'বাংলা', 'Bengali', 'bn', null, '🇧🇩'),
  hi('hi', 'हिन्दी', 'Hindi', 'hi', null, '🇮🇳'),
  pt('pt', 'Português', 'Portuguese', 'pt', null, '🇧🇷'),
  ru('ru', 'Русский', 'Russian', 'ru', null, '🇷🇺'),
  fr('fr', 'Français', 'French', 'fr', null, '🇫🇷');

  const AppLocale(
    this.id,
    this.nativeName,
    this.englishName,
    this.languageCode,
    this.countryCode,
    this.flag,
  );

  final String id;
  final String nativeName;
  final String englishName;
  final String? languageCode;
  final String? countryCode;
  final String flag;

  bool get isRTL {
    if (this == AppLocale.system) return false;
    return _rtlLanguageCodes.contains(languageCode);
  }

  /// 是否为机器翻译（覆盖率低于80%的语言）
  bool get isMachineTranslated {
    switch (this) {
      case AppLocale.system:
      case AppLocale.zhCN:
      case AppLocale.en:
      case AppLocale.zhTW:
      case AppLocale.ja:
      case AppLocale.ko:
        return false;
      case AppLocale.de:
      case AppLocale.it:
      case AppLocale.es:
      case AppLocale.fr:
      case AppLocale.ru:
      case AppLocale.pt:
        return false;
      case AppLocale.ar:
      case AppLocale.bn:
      case AppLocale.hi:
        return true;
    }
  }

  TextDirection get textDirection =>
      isRTL ? TextDirection.rtl : TextDirection.ltr;

  Locale get locale {
    if (this == AppLocale.system) {
      return WidgetsBinding.instance.platformDispatcher.locale;
    }
    if (countryCode != null) return Locale(languageCode!, countryCode);
    return Locale(languageCode!);
  }

  static AppLocale fromId(String id) {
    return AppLocale.values.firstWhere(
      (e) => e.id == id,
      orElse: () => AppLocale.system,
    );
  }

  static List<AppLocale> get selectable =>
      AppLocale.values.where((e) => e != AppLocale.system).toList();

  static List<AppLocale> smartSorted() {
    final locales = selectable.toList();
    final systemLocale = WidgetsBinding.instance.platformDispatcher.locale;
    final systemLang = systemLocale.languageCode;
    final systemCountry = systemLocale.countryCode;

    locales.sort((a, b) {
      final aScore = _relevanceScore(a, systemLang, systemCountry);
      final bScore = _relevanceScore(b, systemLang, systemCountry);
      return bScore.compareTo(aScore);
    });

    return locales;
  }

  static int _relevanceScore(
    AppLocale locale,
    String systemLang,
    String? systemCountry,
  ) {
    if (locale.languageCode == systemLang) {
      if (locale.countryCode != null && locale.countryCode == systemCountry) {
        return 100;
      }
      return 80;
    }
    switch (locale.id) {
      case 'zh_CN':
        return 50;
      case 'en':
        return 40;
      default:
        return 20;
    }
  }
}

Locale _resolveSystemLocale(Locale systemLocale) {
  final supported = AppLocale.selectable;
  for (final appLocale in supported) {
    if (appLocale.countryCode != null) {
      if (systemLocale.languageCode == appLocale.languageCode &&
          systemLocale.countryCode == appLocale.countryCode) {
        return appLocale.locale;
      }
    }
    if (systemLocale.languageCode == appLocale.languageCode) {
      return appLocale.locale;
    }
  }
  if (systemLocale.languageCode == 'zh') {
    return AppLocale.zhCN.locale;
  }
  return AppLocale.zhCN.locale;
}

bool _isSystemLocaleRTL() {
  final systemLocale = WidgetsBinding.instance.platformDispatcher.locale;
  return _rtlLanguageCodes.contains(systemLocale.languageCode);
}

final systemLocaleVersionProvider =
    NotifierProvider<SystemLocaleVersionNotifier, int>(
      SystemLocaleVersionNotifier.new,
    );

class SystemLocaleVersionNotifier extends Notifier<int> {
  @override
  int build() => 0;

  void increment() => state = state + 1;
}

final appLocaleProvider = Provider<Locale>((ref) {
  ref.watch(systemLocaleVersionProvider);
  final settings = ref.watch(generalSettingsProvider);
  final languageId = settings.languageId;

  if (languageId == 'system') {
    final systemLocale = WidgetsBinding.instance.platformDispatcher.locale;
    return _resolveSystemLocale(systemLocale);
  }

  final appLocale = AppLocale.fromId(languageId);
  return appLocale.locale;
});

final appTextDirectionProvider = Provider<TextDirection>((ref) {
  ref.watch(systemLocaleVersionProvider);
  final settings = ref.watch(generalSettingsProvider);
  final languageId = settings.languageId;

  if (languageId == 'system') {
    return _isSystemLocaleRTL() ? TextDirection.rtl : TextDirection.ltr;
  }

  return AppLocale.fromId(languageId).textDirection;
});

final supportedLocalesProvider = Provider<List<Locale>>((ref) {
  return AppLocale.selectable.map((e) => e.locale).toList();
});

final localeDateFormatProvider = Provider<DateFormat>((ref) {
  final locale = ref.watch(appLocaleProvider);
  return DateFormat.yMMMd(locale.toLanguageTag());
});

final localeNumberFormatProvider = Provider<NumberFormat>((ref) {
  final locale = ref.watch(appLocaleProvider);
  return NumberFormat.decimalPattern(locale.toLanguageTag());
});