// Copyright (c) Microsoft. All rights reserved.

using System;
using TileUpdateAfterSuspension.Common;
using Windows.ApplicationModel;
using Windows.ApplicationModel.Activation;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;

namespace TileUpdateAfterSuspension
{
    /// <summary>
    /// Provides application-specific behavior to supplement the default Application class.
    /// </summary>
    sealed partial class App : Application
    {
        /// <summary>
        /// Initializes the singleton Application object.  This is the first line of authored code
        /// executed, and as such is the logical equivalent of main() or WinMain().
        /// </summary>
        public App()
        {
            this.InitializeComponent();
            this.Suspending += OnSuspending;
        }

        /// <summary>
        /// Invoked when the application is launched normally by the end user.  Other entry points
        /// will be used such as when the application is launched to open a specific file.
        /// </summary>
        /// <param name="e">Details about the launch request and process.</param>
        protected override async void OnLaunched(LaunchActivatedEventArgs e)
        {
            Frame rootFrame = Window.Current.Content as Frame;

            // Do not repeat app initialization when the Window already has content,
            // just ensure that the window is active

            if (rootFrame == null)
            {
                // Create a Frame to act as the navigation context and navigate to the first page
                rootFrame = new Frame();

                // Set the default language
                rootFrame.Language = Windows.Globalization.ApplicationLanguages.Languages[0];

                rootFrame.NavigationFailed += OnNavigationFailed;

                if (e.PreviousExecutionState == ApplicationExecutionState.Terminated)
                {
                    // Restore the saved session state only when appropriate
                    try
                    {
                        await SuspensionManager.RestoreAsync();
                    }
                    catch (SuspensionManagerException)
                    {
                        //Something went wrong restoring state.
                        //Assume there is no state and continue
                    }
                }

                // Place the frame in the current Window
                Window.Current.Content = rootFrame;
            }

            //MainPage is always in rootFrame so we don't have to worry about restoring the navigation state on resume
            rootFrame.Navigate(typeof(MainPage), e.Arguments);

            // Ensure the current window is active
            Window.Current.Activate();
        }

        /// <summary>
        /// Invoked when Navigation to a certain page fails
        /// </summary>
        /// <param name="sender">The Frame which failed navigation</param>
        /// <param name="e">Details about the navigation failure</param>
        void OnNavigationFailed(object sender, NavigationFailedEventArgs e)
        {
            throw new Exception("Failed to load Page " + e.SourcePageType.FullName);
        }

        /// <summary>
        /// Invoked when application execution is being suspended.  Application state is saved
        /// without knowing whether the application will be terminated or resumed with the contents
        /// of memory still intact.
        /// </summary>
        /// <param name="sender">The source of the suspend request.</param>
        /// <param name="e">Details about the suspend request.</param>
        private async void OnSuspending(object sender, SuspendingEventArgs e)
        {
            var deferral = e.SuspendingOperation.GetDeferral();
            await SuspensionManager.SaveAsync();

            // Check whether there is an action to perform as the result 
            // of a new tile being pinned.
            if (OnNewTilePinned != null)
            {
                // Perform the action.
                OnNewTilePinned();

                // Clear the action when finished. 
                OnNewTilePinned = null;
            }

            deferral.Complete();
        }

        /// <summary>
        /// Gets or sets the action to be performed as the result of a new tile being pinned.
        /// </summary>
        public static Action OnNewTilePinned { get; set; }
    }
}
