custom-plugin-flutter-skill-localization

What this skill does

# custom-plugin-flutter: Localization Skill

## Quick Start - Production Localization Setup

```yaml
# pubspec.yaml
dependencies:
  flutter_localizations:
    sdk: flutter
  intl: ^0.19.0

flutter:
  generate: true

# l10n.yaml (create in project root)
arb-dir: lib/l10n
template-arb-file: app_en.arb
output-localization-file: app_localizations.dart
output-class: AppLocalizations
nullable-getter: false
```

```dart
// lib/l10n/app_en.arb
{
  "@@locale": "en",
  "appTitle": "My App",
  "@appTitle": {
    "description": "The app title"
  },
  "welcomeMessage": "Welcome, {name}!",
  "@welcomeMessage": {
    "description": "Welcome message with user name",
    "placeholders": {
      "name": {
        "type": "String",
        "example": "John"
      }
    }
  },
  "itemCount": "{count, plural, =0{No items} =1{1 item} other{{count} items}}",
  "@itemCount": {
    "description": "Number of items",
    "placeholders": {
      "count": {
        "type": "int"
      }
    }
  }
}

// lib/l10n/app_tr.arb
{
  "@@locale": "tr",
  "appTitle": "Uygulamam",
  "welcomeMessage": "Hoş geldin, {name}!",
  "itemCount": "{count, plural, =0{Öğe yok} =1{1 öğe} other{{count} öğe}}"
}

// main.dart
import 'package:flutter_gen/gen_l10n/app_localizations.dart';

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      localizationsDelegates: AppLocalizations.localizationsDelegates,
      supportedLocales: AppLocalizations.supportedLocales,
      locale: Locale('en'),
      home: HomePage(),
    );
  }
}

// Usage in widgets
Text(AppLocalizations.of(context).welcomeMessage('John'))
Text(AppLocalizations.of(context).itemCount(5))
```

## 1. ARB File Syntax

### Basic Messages

```json
{
  "@@locale": "en",

  "greeting": "Hello",
  "@greeting": {
    "description": "A simple greeting"
  },

  "pageTitle": "Settings Page",
  "@pageTitle": {
    "description": "Title of the settings page",
    "context": "SettingsPage"
  }
}
```

### Placeholders

```json
{
  "welcomeUser": "Welcome, {userName}!",
  "@welcomeUser": {
    "placeholders": {
      "userName": {
        "type": "String",
        "example": "Alice"
      }
    }
  },

  "priceLabel": "Price: {price}",
  "@priceLabel": {
    "placeholders": {
      "price": {
        "type": "double",
        "format": "currency",
        "optionalParameters": {
          "symbol": "$",
          "decimalDigits": 2
        }
      }
    }
  },

  "dateLabel": "Date: {date}",
  "@dateLabel": {
    "placeholders": {
      "date": {
        "type": "DateTime",
        "format": "yMMMd"
      }
    }
  }
}
```

### Pluralization

```json
{
  "cartItems": "{count, plural, =0{Your cart is empty} =1{1 item in cart} other{{count} items in cart}}",
  "@cartItems": {
    "placeholders": {
      "count": {
        "type": "int"
      }
    }
  },

  "remainingAttempts": "{count, plural, =0{No attempts remaining} =1{1 attempt remaining} other{{count} attempts remaining}}",
  "@remainingAttempts": {
    "placeholders": {
      "count": {
        "type": "int"
      }
    }
  }
}
```

### Gender Selection

```json
{
  "userGreeting": "{gender, select, male{Mr. {name}} female{Ms. {name}} other{{name}}}",
  "@userGreeting": {
    "placeholders": {
      "gender": {
        "type": "String"
      },
      "name": {
        "type": "String"
      }
    }
  }
}
```

## 2. Date & Number Formatting

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

// Date formatting
final dateFormatter = DateFormat.yMMMd(locale);
Text(dateFormatter.format(DateTime.now()))

// Number formatting
final numberFormatter = NumberFormat.decimalPattern(locale);
Text(numberFormatter.format(1234567.89))

// Currency formatting
final currencyFormatter = NumberFormat.currency(
  locale: locale,
  symbol: '\$',
  decimalDigits: 2,
);
Text(currencyFormatter.format(99.99))

// Percentage
final percentFormatter = NumberFormat.percentPattern(locale);
Text(percentFormatter.format(0.75)) // 75%

// Compact notation
final compactFormatter = NumberFormat.compact(locale: locale);
Text(compactFormatter.format(1500000)) // 1.5M
```

## 3. Dynamic Locale Switching

```dart
class LocaleProvider extends ChangeNotifier {
  Locale _locale = Locale('en');

  Locale get locale => _locale;

  void setLocale(Locale locale) {
    if (!AppLocalizations.supportedLocales.contains(locale)) return;
    _locale = locale;
    notifyListeners();
  }

  Future<void> loadSavedLocale() async {
    final prefs = await SharedPreferences.getInstance();
    final languageCode = prefs.getString('languageCode');
    if (languageCode != null) {
      _locale = Locale(languageCode);
      notifyListeners();
    }
  }

  Future<void> saveLocale(Locale locale) async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.setString('languageCode', locale.languageCode);
    setLocale(locale);
  }
}

// Usage with Provider
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Consumer<LocaleProvider>(
      builder: (context, localeProvider, child) {
        return MaterialApp(
          locale: localeProvider.locale,
          localizationsDelegates: AppLocalizations.localizationsDelegates,
          supportedLocales: AppLocalizations.supportedLocales,
          home: HomePage(),
        );
      },
    );
  }
}

// Language selector
class LanguageSelector extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final localeProvider = context.watch<LocaleProvider>();

    return DropdownButton<Locale>(
      value: localeProvider.locale,
      items: AppLocalizations.supportedLocales.map((locale) {
        return DropdownMenuItem(
          value: locale,
          child: Text(_getLanguageName(locale)),
        );
      }).toList(),
      onChanged: (locale) {
        if (locale != null) {
          localeProvider.saveLocale(locale);
        }
      },
    );
  }

  String _getLanguageName(Locale locale) {
    switch (locale.languageCode) {
      case 'en': return 'English';
      case 'tr': return 'Türkçe';
      case 'es': return 'Español';
      default: return locale.languageCode;
    }
  }
}
```

## 4. RTL (Right-to-Left) Support

```dart
// Automatic direction based on locale
MaterialApp(
  locale: Locale('ar'), // Arabic - RTL
  localizationsDelegates: [
    GlobalMaterialLocalizations.delegate,
    GlobalWidgetsLocalizations.delegate,
    GlobalCupertinoLocalizations.delegate,
  ],
)

// Check directionality
final isRtl = Directionality.of(context) == TextDirection.rtl;

// Force direction
Directionality(
  textDirection: TextDirection.rtl,
  child: MyWidget(),
)

// Directional padding
Padding(
  padding: EdgeInsetsDirectional.only(start: 16, end: 8),
  child: Text('Directional padding'),
)

// Positioned directionally
PositionedDirectional(
  start: 0,
  end: null,
  child: widget,
)

// Row with automatic alignment
Row(
  textDirection: Directionality.of(context),
  children: [...],
)

// Icons that should flip
Transform.flip(
  flipX: isRtl,
  child: Icon(Icons.arrow_forward),
)
```

## 5. Testing Localization

```dart
void main() {
  testWidgets('displays localized text in Turkish', (tester) async {
    await tester.pumpWidget(
      MaterialApp(
        locale: Locale('tr'),
        localizationsDelegates: AppLocalizations.localizationsDelegates,
        supportedLocales: AppLocalizations.supportedLocales,
        home: HomePage(),
      ),
    );

    expect(find.text('Hoş geldin!'), findsOneWidget);
  });

  testWidgets('handles pluralization correctly', (tester) async {
    await tester.pumpWidget(
      MaterialApp(
        locale: Locale('en'),
        localizationsDelegates: AppLocalizations.localizationsDelegates,
        supportedLocales: AppLocalizations.supportedLocales,
        home: Builder(
          builder: (context) {
            return Column(
              children: [
                Text(AppLocalizations.of(context).itemCount(0)),
                Text(Ap