//This is a User Model , struct that contains the user's login data
struct User {
    var username: String?
    var password: String?
}

//This is the protocol to implement in the View Controller , being called by the presenter.
protocol LoginView: class {
    func didLogin (error: Error?)
}

// The presenter's protocol
protocol LoginPresenter {
    init (view: LoginView?, user: User?)
    func login ()
}

//The presenter itself , implementing the Login Presetner Protocol
struct LoginViewPresenter: LoginPresenter {
    weak var view: LoginView?
    var user: User?

    init(view: LoginView?, user: User?) {
        self.view = view
        self.user = user
    }

    func login() {
      // Here you will place your login logic, including network call etc.
      // This is a sample only to demonstrate what happnes when you call didLogin() with no error
        view?.didLogin(error: nil)
    }
}

class LoginViewController: UIViewController, LoginView {

  //MARK: Properties
    var presenter: LoginPresenter?
    @IBOutlet weak var loginButton: UIButton!

  //MARK: Actions
    @IBAction func setDefaultLabelText(_ sender: UIButton) {
      presenter?.login() //Calling login method, through the presenter
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        setupLayout()
    }

    //Implementing the didLogin method, placed in the LoginView Protocol
    func didLogin(error: Error?) {
        if let error = error {
            print("Error -> \(error.localizedDescription)")
        } else {
            print("Logged in with user \(presenter?.user)")
        }
    }
}