UserDefaults.swift

import Foundation

// MARK: UserDefaults extension
extension UserDefaults {
    struct SomeApp: UserDefaultable {
        enum UserDefaultKey: String {
            case someItem
        }
        
        private init() {}
    }
}

// MARK: UserDefaultable protocol
public protocol UserDefaultable: KeyNamespaceable {
    associatedtype UserDefaultKey: RawRepresentable
}

public extension UserDefaultable where UserDefaultKey.RawValue == String {
    public static func setValue(_ value: Any?, forKey key: UserDefaultKey) {
        let key = namespace(key)
        UserDefaults.standard.setValue(value, forKey: key)
    }
    
    public static func setCustomObject(_ customObject: Any?, forKey key: UserDefaultKey) {
        let key = namespace(key)
        guard let customObject = customObject else { return }
        let encodedData = NSKeyedArchiver.archivedData(withRootObject: customObject)
        UserDefaults.standard.setValue(encodedData, forKey: key)
    }
    
    public static func object(forKey key: UserDefaultKey) -> Any? {
        let key = namespace(key)
        return UserDefaults.standard.object(forKey: key)
    }
    
    public static func customObject(forKey key: UserDefaultKey) -> Any? {
        let key = namespace(key)
        guard let encodedData = UserDefaults.standard.object(forKey: key) as? Data else { return nil }
        return NSKeyedUnarchiver.unarchiveObject(with: encodedData)
    }
    
    public static func removeObject(forKey key: UserDefaultKey) {
        let key = namespace(key)
        UserDefaults.standard.removeObject(forKey: key)
    }
}

// MARK: KeyNamespaceable protocol
public protocol KeyNamespaceable {}

public extension KeyNamespaceable {
    public static func namespace<Key>(_ key: Key) -> String where Key: RawRepresentable {
        return "\(Self.self).\(key.rawValue)"
    }
}