localisation.swift

//
//  Localization.swift
//  Pokedex
//
//  Created by Rhys Powell on 3/03/2016.
//  Copyright © 2016 Rhys Powell. All rights reserved.
//

import Foundation
import RealmSwift

public class LocalizationHelper {
    
    static func preferredLanguages() -> [String] {
        var languages = NSLocale.preferredLanguages()
            .map { language in
                return language.componentsSeparatedByString("-").first ?? language
        }
        languages.append("en")
        
        return languages
    }
    
    static func predicateForLanguage(language: String) -> NSPredicate {
        return NSPredicate(format: "language.iso639 = %@", language)
    }
    
}

public protocol Localizable {
    
    var language: Language! { get }
    
}

public extension RealmCollectionType where Element : Localizable {
    
    func objectForLanguage(language: String) -> Element? {
        return self
            .filter(LocalizationHelper.predicateForLanguage(language))
            .first
    }
    
    var objectForCurrentLocale: Element? {
        return LocalizationHelper.preferredLanguages()
            .flatMap(objectForLanguage)
            .first
    }
    
}