class BoardingPageViewController: UIPageViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    dataSource = self
    delegate = self
    setViewControllers([getStepOne()], direction: .forward, animated: false, completion: nil)
}

override var preferredStatusBarStyle: UIStatusBarStyle {
    return .lightContent
}

func getStepOne() -> BoardView1ViewController {
    return storyboard!.instantiateViewController(withIdentifier: "BoardView1") as! BoardView1ViewController
}

func getStepTwo() -> BoardView2ViewController {
    return storyboard!.instantiateViewController(withIdentifier: "BoardView2") as! BoardView2ViewController
}

func getStepThree() -> BoardView3ViewController {
    return storyboard!.instantiateViewController(withIdentifier: "BoardView3") as! BoardView3ViewController
}
func getStepFour() -> BoardView4ViewController {
    return storyboard!.instantiateViewController(withIdentifier: "BoardView4") as! BoardView4ViewController
}
func getStepFive() -> BoardView5ViewController {
    return storyboard!.instantiateViewController(withIdentifier: "BoardView5") as! BoardView5ViewController
}
}

extension BoardingPageViewController : UIPageViewControllerDataSource {

func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
    if viewController.isKind(of: BoardView5ViewController.self) {
        // 5 -> 4
        return getStepFour()
    } else if viewController.isKind(of: BoardView4ViewController.self) {
        // 4 -> 3
        return getStepThree()
    } else if viewController.isKind(of: BoardView3ViewController.self) {
        // 3 -> 2
        return getStepTwo()
    } else if viewController.isKind(of: BoardView2ViewController.self) {
        // 2 -> 1
        return getStepOne()
    } else {
        // 0 -> end of the road
        return nil
    }
}

func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
    if viewController.isKind(of: BoardView1ViewController.self) {
        // 0 -> 1
        return getStepTwo()
    } else if viewController.isKind(of: BoardView2ViewController.self) {
        // 1 -> 2
        return getStepThree()
    } else if viewController.isKind(of: BoardView3ViewController.self) {
        // 1 -> 2
        return getStepFour()
    } else if viewController.isKind(of: BoardView4ViewController.self) {
        // 1 -> 2
        return getStepFive()
    } else {
        // 2 -> end of the road
        return nil
    }
}

func presentationCount(for pageViewController: UIPageViewController) -> Int {
    return 5
}

func presentationIndex(for pageViewController: UIPageViewController) -> Int {
    return 0
}

}

extension BoardingPageViewController : UIPageViewControllerDelegate {

}

override func viewDidAppear(_ animated: Bool) {
    chainAni = true
    ani0()
}

func ani0() {
    if chainAni != true {
        return
    }
    UIView.animate(withDuration: 1, delay: 1, animations: {
        self.handPic.alpha = 1
    }) { (false) in
        self.ani1()
    }
}
func ani1() {
    if chainAni != true {
        return
    }
    UIView.animate(withDuration: 1.5, delay: 1, usingSpringWithDamping: 0.5, initialSpringVelocity: 0, options: [], animations: {
        self.highlightAction(any: self.handPic)
        self.highlightAction(any: self.folderBtn)
    }) { (false) in
        self.ani2()
    }
}
func ani2() {
    if chainAni != true {
        return
    }
    UIView.animate(withDuration: 1.5, delay: 1, animations: {
        self.unhighlightAction(any: self.handPic)
        self.unhighlightAction(any: self.folderBtn)
    }) { (false) in
        self.ani3()
    }
}
func ani3() {
    if chainAni != true {
        return
    }
    UIView.animate(withDuration: 0.5, delay: 0, animations: {
        self.handPic.alpha = 0
        self.alertImg.alpha = 1
        self.alertImg.transform = .identity
    }) { (false) in
        self.ani4()
    }
}

func clearAni() {
    alertImg.image = #imageLiteral(resourceName: "alert1")

    darkView.removeFromSuperview()
    screenView.removeFromSuperview()

    mainImg.alpha = 1
    alertImg.alpha = 0
    alert2Img.alpha = 0
    handPic.alpha = 0
    handPic.transform = .identity
    hand2Pic.alpha = 0
    hand2Pic.transform = .identity
    newFolderImg.alpha = 0
    newFolderImg.transform = .identity
}

override func viewDidDisappear(_ animated: Bool) {
    clearAni()
    chainAni = false
}

func clearAni() {
alertImg.image = #imageLiteral(resourceName: "alert1")

mainImg.layer.removeAllAnimations()
mainLbl.layer.removeAllAnimations()
alertImg.layer.removeAllAnimations()
alert2Img.layer.removeAllAnimations()
folderBtn.layer.removeAllAnimations()
handPic.layer.removeAllAnimations()
hand2Pic.layer.removeAllAnimations()
darkView.layer.removeAllAnimations()


mainImg.alpha = 1
alertImg.alpha = 0
alert2Img.alpha = 0
handPic.alpha = 0
handPic.transform = .identity
hand2Pic.alpha = 0
hand2Pic.transform = .identity
newFolderImg.alpha = 0
newFolderImg.transform = .identity
}