User.swift

@objc(User)
final class User: NSObject, NSCoding {

  let userId: Int
  var email: String?
  let name: String
  var recentGames: [Int]?

  /// nscoding keys
  private static let ID_KEY = "id"
  private static let EMAIL_KEY = "email"
  private static let NAME_KEY = "name"
  private static let RECENT_GAMES_KEY = "recentGames"

  init(userId: Int, email: String?, name: String, recentGames: [Int]?) {
    self.userId = userId
    self.email = email
    self.name = name
    self.recentGames = recentGames
  }

  required convenience init?(coder aDecoder: NSCoder) {
    let userId = aDecoder.decodeInteger(forKey: User.ID_KEY)
    let email = aDecoder.decodeObject(forKey: User.EMAIL_KEY) as? String ?? nil
    let name = aDecoder.decodeObject(forKey: User.NAME_KEY) as? String ?? ""
    let recentGames = aDecoder.decodeObject(forKey: User.RECENT_GAMES_KEY) as? [Int] ?? nil

    self.init(userId: userId, email: email, name: name, recentGames: recentGames)
  }

  func encode(with aCoder: NSCoder) {
    aCoder.encode(userId, forKey: User.ID_KEY)
    aCoder.encode(email, forKey: User.EMAIL_KEY)
    aCoder.encode(name, forKey: User.NAME_KEY)
    aCoder.encode(recentGames, forKey: User.RECENT_GAMES_KEY)
  }
}