final class SayHelloViewController: UIViewController {

    @IBOutlet weak var nameTextField: UITextField!
    @IBOutlet weak var validateButton: UIButton!
    @IBOutlet weak var greetingLabel: UILabel!

    private let viewModel = SayHelloViewModel()
    private let bag = DisposeBag()

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

    private func bindViewModel() {
        let inputs = SayHelloViewModel.Input(name: nameTextField.rx.text.orEmpty.asObservable(),
                                             validate: validateButton.rx.tap.asObservable())
        let outputs = viewModel.transform(input: inputs)
        outputs.greeting
            .drive(greetingLabel.rx.text)
            .disposed(by: bag)
    }
}