Resources/
└── Localizable.xcstrings    # String catalog with all translations

Sources/Localization/
├── LocalizedStrings.swift   # Type-safe string access
├── LocalizationManager.swift # Runtime language switching
└── LocalizedPreview.swift   # SwiftUI preview helpers

// Generated enum for type-safe access
enum L10n {
    static let appName = String(localized: "app_name")
    static let welcomeMessage = String(localized: "welcome_message")

    enum Settings {
        static let title = String(localized: "settings_title")
        static let language = String(localized: "settings_language")
    }
}

// Usage
Text(L10n.appName)
Text(L10n.Settings.title)

// In String Catalog, define plural rules
// key: "items_count"
// variations:
//   - zero: "No items"
//   - one: "1 item"
//   - other: "%lld items"

Text(String(localized: "items_count \(count)",
            defaultValue: "\(count) items"))

// In String Catalog:
// key: "greeting"
// value: "Hello, %@!"

let name = "Alice"
Text(String(localized: "greeting \(name)"))

// Preview in different locale
struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
            .environment(\.locale, Locale(identifier: "es"))
    }
}

// Automatic localization
Text("Hello, World!")  // Uses String Catalog automatically

// Explicit localized string
Text(String(localized: "custom_key"))

// With type-safe enum (generated)
Text(L10n.welcomeMessage)

label.text = String(localized: "hello_world")
// or
label.text = NSLocalizedString("hello_world", comment: "Greeting")

// Good: Descriptive, hierarchical
"settings.appearance.theme"
"onboarding.step1.title"
"error.network.connection_failed"

// Avoid: Vague or hardcoded text as key
"button1"
"Hello, World!"

String(localized: "delete_confirmation",
       comment: "Alert message asking user to confirm deletion")

// Numbers - Use FormatStyle
Text(price, format: .currency(code: "USD"))

// Dates - Use FormatStyle
Text(date, format: .dateTime.month().day())

// Lists - Use ListFormatStyle
Text(items, format: .list(type: .and))

// Automatic with SwiftUI
// For manual layout adjustments:
.environment(\.layoutDirection, .rightToLeft)

#Preview {
    ContentView()
        .environment(\.locale, Locale(identifier: "ja"))
}