class ManagedTextField: UITextField {

    weak var textFieldManagerDelegate : TextFieldManger?

    override init(frame: CGRect) {
        super.init(frame: frame)
    }

    private var previousValue : String?

    private var timer = Timer()

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    override func draw(_ rect: CGRect) {
        super.draw(rect)
        commonInit()
    }

    private func commonInit() {
        NotificationCenter.default.addObserver(forName: UITextField.textDidChangeNotification, object: self, queue: nil, using: {
            [weak self]
            notification in
            guard let strongSelf = self else { return }
            guard let object = notification.object as? ManagedTextField, object == self else { return }
            if strongSelf.previousValue != strongSelf.text {
                strongSelf.timer.invalidate()
                strongSelf.timer = Timer.scheduledTimer(withTimeInterval: 0.2, repeats: false, block: { timer in
                    strongSelf.textFieldManagerDelegate?.makeApiRequest(withValue: strongSelf.text)
                })
                if let newCount = strongSelf.text?.count,
                let oldCount = strongSelf.previousValue?.count {
                    if newCount < oldCount {
                        strongSelf.timer.invalidate()
                    }
                }
            }
            strongSelf.previousValue = strongSelf.text
        })
    }

}