/*

    Copyright (C) 2016 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    LargeElementViewController is used in two different ways:

     1. Contained within ExampleContainerViewController, when its width is large.

     2. Presented by SmallElementViewController, when the ExampleContainerViewController's width is small.

     It shows a large version of the element. When it is presented, tapping on it will dismiss it.

 */

import UIKit

class LargeElementViewController: UIViewController {

    var widthConstraint: NSLayoutConstraint?

    override func updateViewConstraints() {

        super.updateViewConstraints()

        /*

            If we are not being presented full-screen,

            then add a constraint to make this view no wider than our superview's readable content guide.

         */

        if presentingViewController == nil && widthConstraint == nil, let superview = view.superview {

            widthConstraint = view.widthAnchor.constraint(lessThanOrEqualTo: superview.readableContentGuide.widthAnchor)

            widthConstraint?.isActive = true

        }

    }

    override func viewWillAppear(_ animated: Bool) {

        super.viewWillAppear(animated)

        /*

            When this view appears, if we are being presented,

            add a tap gesture recognizer so we can dismiss when we are tapped.

         */

        if isBeingPresented {

            let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(self.tapped))

            view.addGestureRecognizer(tapGestureRecognizer)

        }

    }

    func tapped(_ gestureRecognizer: UITapGestureRecognizer) {

        if gestureRecognizer.state == .ended {

            dismiss(animated: true, completion: nil)

        }

    }

}