/*

    Copyright (C) 2017 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    Manages app lifecycle  split view.

 */

import UIKit

import Photos

@UIApplicationMain

class AppDelegate: UIResponder, UIApplicationDelegate, UISplitViewControllerDelegate {

    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey : Any]?) -> Bool {

        // Override point for customization after application launch.

        let splitViewController = self.window!.rootViewController as! UISplitViewController

        #if os(iOS)

            let navigationController = splitViewController.viewControllers.last! as! UINavigationController

            navigationController.topViewController!.navigationItem.leftBarButtonItem = splitViewController.displayModeButtonItem

        #endif

        splitViewController.delegate = self

        return true

    }

    // MARK: Split view

    func splitViewController(_ splitViewController: UISplitViewController, collapseSecondary secondaryViewController:UIViewController, onto primaryViewController:UIViewController) -> Bool {

        guard let secondaryAsNavController = secondaryViewController as? UINavigationController else { return false }

        guard let topAsDetailController = secondaryAsNavController.topViewController as? AssetGridViewController else { return false }

        if topAsDetailController.fetchResult == nil {

            // Return true to indicate that we have handled the collapse by doing nothing; the secondary controller will be discarded.

            return true

        }

        return false

    }

    func splitViewController(_ splitViewController: UISplitViewController, showDetail vc: UIViewController, sender: Any?) -> Bool {

        // Let the storyboard handle the segue for every case except going from detail:assetgrid to detail:asset.

        guard !splitViewController.isCollapsed else { return false }

        guard !(vc is UINavigationController) else { return false }

        guard let detailNavController =

            splitViewController.viewControllers.last! as? UINavigationController,

            detailNavController.viewControllers.count == 1

            else { return false }

        detailNavController.pushViewController(vc, animated: true)

        return true

    }

}