using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.ApplicationModel;
using Windows.ApplicationModel.Activation;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Media.Animation;
using Windows.UI.Xaml.Navigation;

// The Blank Application template is documented at http://go.microsoft.com/fwlink/?LinkId=391641

namespace Xamarin.Forms.ControlGallery.WindowsPhone
{
	/// <summary>
	/// Provides application-specific behavior to supplement the default Application class.
	/// </summary>
	public sealed partial class App
	{
		TransitionCollection _transitions;

		/// <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()
		{
			InitializeComponent();
			Suspending += OnSuspending;
		}

		/// <summary>
		/// Invoked when the application is launched normally by the end user.  Other entry points
		/// will be used when the application is launched to open a specific file, to display
		/// search results, and so forth.
		/// </summary>
		/// <param name="e">Details about the launch request and process.</param>
		protected override void OnLaunched(LaunchActivatedEventArgs e)
		{
#if DEBUG
			if (System.Diagnostics.Debugger.IsAttached)
			{
				DebugSettings.EnableFrameRateCounter = true;
			}
#endif

			var rootFrame = Window.Current.Content as global::Windows.UI.Xaml.Controls.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 global::Windows.UI.Xaml.Controls.Frame();

				// TODO: change this value to a cache size that is appropriate for your application
				rootFrame.CacheSize = 1;

				Forms.Init (e);
				FormsMaps.Init (Controls.App.Secrets["WinPhoneMapsAuthKey"]);

				if (e.PreviousExecutionState == ApplicationExecutionState.Terminated)
				{
					// TODO: Load state from previously suspended application
				}

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

			if (rootFrame.Content == null)
			{
				// Removes the turnstile navigation for startup.
				if (rootFrame.ContentTransitions != null)
				{
					_transitions = new TransitionCollection();
					foreach (var c in rootFrame.ContentTransitions)
					{
						_transitions.Add(c);
					}
				}

				rootFrame.ContentTransitions = null;
				rootFrame.Navigated += RootFrame_FirstNavigated;

				// When the navigation stack isn't restored navigate to the first page,
				// configuring the new page by passing required information as a navigation
				// parameter
				if (!rootFrame.Navigate(typeof(MainPage), e.Arguments))
				{
					throw new Exception("Failed to create initial page");
				}
			}

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

		/// <summary>
		/// Restores the content transitions after the app has launched.
		/// </summary>
		/// <param name="sender">The object where the handler is attached.</param>
		/// <param name="e">Details about the navigation event.</param>
		void RootFrame_FirstNavigated(object sender, global::Windows.UI.Xaml.Navigation.NavigationEventArgs e)
		{
			var rootFrame = sender as global::Windows.UI.Xaml.Controls.Frame;
			rootFrame.ContentTransitions = _transitions ?? new TransitionCollection() { new NavigationThemeTransition() };
			rootFrame.Navigated -= RootFrame_FirstNavigated;
		}

		/// <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>
		void OnSuspending(object sender, SuspendingEventArgs e)
		{
			var deferral = e.SuspendingOperation.GetDeferral();

			// TODO: Save application state and stop any background activity
			deferral.Complete();
		}
	}
}