/*

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

See LICENSE.txt for this sample’s licensing information

Abstract:

An extension that gives information about how view controllers will be shown, for determining disclosure indicator visibility and row deselection.

*/

import UIKit

extension UIViewController {

    /**

        Returns whether calling `showViewController(_:sender:)` would cause a

        navigation "push" to occur.

    */

    func willShowingViewControllerPushWithSender(_ sender: AnyObject?) -> Bool {

        // Find and ask the right view controller about showing.

        if let target = targetViewController(forAction: #selector(UIViewController.willShowingViewControllerPushWithSender(_:)), sender: sender) {

            return target.willShowingViewControllerPushWithSender(sender)

        }

        // Or if we can't find one, we won't be pushing.

        return false

    }

    /**

        Returns whether calling `showDetailViewController(_:sender:)` would cause a

        navigation "push" to occur.

    */

    func willShowingDetailViewControllerPushWithSender(_ sender: AnyObject?) -> Bool {

        // Find and ask the right view controller about showing.

        if let target = targetViewController(forAction: #selector(UIViewController.willShowingDetailViewControllerPushWithSender(_:)), sender: sender) {

            return target.willShowingDetailViewControllerPushWithSender(sender)

        }

        // Or if we can't find one, we won't be pushing.

        return false

    }

}

extension UINavigationController {

    override func willShowingViewControllerPushWithSender(_ sender: AnyObject?) -> Bool {

        // Navigation Controllers always push for `showViewController(_:sender:)`.

        return true

    }

}

extension UISplitViewController {

    override func willShowingViewControllerPushWithSender(_ sender: AnyObject?) -> Bool {

        // Split View Controllers never push for `showViewController(_:sender:)`.

        return false

    }

    override func willShowingDetailViewControllerPushWithSender(_ sender: AnyObject?) -> Bool {

        if isCollapsed {

            /*

                If we're collapsed, re-ask this question as `showViewController(_:sender:)`

                to our primary view controller.

            */

            let target = viewControllers.last

            return target?.willShowingViewControllerPushWithSender(sender) ?? false

        }

        // Otherwise, we don't push for `showDetailViewController(_:sender:)`.

        return false

    }

}