Auto slide the view when keyboard appears

// Auto slide the view when keyboard appears
// https://github.com/priore/DPKeyboardManager
//
// HOW TO USE:
//
// import UIKit
// class DPBaseViewController: UIViewController {
//    let keyboardManager = DPKeyboardManager()
//    override func viewDidAppear(_ animated: Bool) {
//        super.viewDidAppear(animated)
//        keyboardManager.enableKeybaordEvents(self.view)
//    }
//
//    override func viewWillDisappear(_ animated: Bool) {
//        super.viewWillDisappear(animated)
//        keyboardManager.disableKeyboardEvents()
//    }
//}

import UIKit
import Foundation

open class DPKeyboardManager {

    private weak var containerView: UIView?

    @objc open var currentView: UIView?
    @objc open var keyboardRect: CGRect = CGRect.zero
    @objc open var keyboardPadding: CGFloat = 10.0

    @objc public init() {
        // NOP
    }

    @objc public init(_ view: UIView) {
        enableKeybaordEvents(view)
    }

    deinit {
        disableKeyboardEvents()
    }

    @objc open func enableKeybaordEvents(_ view: UIView) {

        containerView = view

        NotificationCenter.default.addObserver(self, selector: #selector(textDidBeginEditing), name: NSNotification.Name.UITextFieldTextDidBeginEditing, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(textDidBeginEditing), name: NSNotification.Name.UITextViewTextDidBeginEditing, object: nil)

        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    }

    @objc open func disableKeyboardEvents() {

        NotificationCenter.default.removeObserver(self)
    }

    // MARK: - Keyboard

    @objc private func keyboardWillShow(notification:NSNotification) {

        let userInfo = notification.userInfo!
        let keyboardFrame:NSValue = userInfo[UIKeyboardFrameEndUserInfoKey] as! NSValue
        self.keyboardRect = keyboardFrame.cgRectValue

        translateTextField()
    }

    @objc private func keyboardWillHide(notification:NSNotification) {

        UIView.animate(withDuration: 0.25) {
            DispatchQueue.main.async {
                self.containerView?.transform = CGAffineTransform.identity
            }
        }
    }

    // MARK: - UITextFiled

    @objc private func textDidBeginEditing(norification:NSNotification) {
        self.currentView = norification.object as? UIView
        translateTextField()
    }


    @objc private func textFieldDidBeginEditingAction(_ textField: UITextField) {
        self.currentView = textField
        translateTextField()
    }

    @objc private func translateTextField() {

        if let view = currentView, keyboardRect.height > 0 {
            let rect = view.superview?.convert(view.frame, to: nil)
            if let maxY = rect?.maxY, maxY > keyboardRect.minY {
                let delta = maxY - keyboardRect.minY + keyboardPadding
                UIView.animate(withDuration: 0.25) {
                    DispatchQueue.main.async {
                        self.containerView?.transform = CGAffineTransform.identity.translatedBy(x: 0, y: -delta)
                    }
                }
            }
        }

    }

}