Decouple UI logic from backend

src/GitHub.App/Authentication/TwoFactorChallengeHandler.cs

@@ -2,32 +2,34 @@
 using System.ComponentModel.Composition;
 using System.Reactive.Linq;
 using GitHub.ViewModels;
-using Microsoft.VisualStudio.PlatformUI;
 using Octokit;
 using ReactiveUI;
+using GitHub.UI;
 
 namespace GitHub.Authentication
 {
     [Export(typeof(ITwoFactorChallengeHandler))]
     public class TwoFactorChallengeHandler : ITwoFactorChallengeHandler
     {
-        readonly IServiceProvider serviceProvider;
+        //readonly IServiceProvider serviceProvider;
+        readonly Lazy<ITwoFactorDialog> lazyTwoFactorDialog;
 
         [ImportingConstructor]
-        public TwoFactorChallengeHandler(IServiceProvider serviceProvider)
+        public TwoFactorChallengeHandler(Lazy<ITwoFactorDialog> twoFactorDialog)
         {
-            this.serviceProvider = serviceProvider;
+            //this.serviceProvider = serviceProvider;
+            this.lazyTwoFactorDialog = twoFactorDialog;
         }
 
         public IObservable<TwoFactorChallengeResult> HandleTwoFactorException(TwoFactorRequiredException exception)
         {
-            var twoFactorDialog = (TwoFactorDialogViewModel)serviceProvider.GetService(typeof(TwoFactorDialogViewModel));
-            var twoFactorView = (IViewFor<TwoFactorDialogViewModel>)serviceProvider.GetService(typeof(IViewFor<TwoFactorDialogViewModel>));
+            var twoFactorDialog = lazyTwoFactorDialog.Value as TwoFactorDialogViewModel;
+            //var twoFactorView = (IViewFor<TwoFactorDialogViewModel>)serviceProvider.GetService(typeof(IViewFor<TwoFactorDialogViewModel>));
 
             return Observable.Start(() =>
             {
-                twoFactorView.ViewModel = twoFactorDialog;
-                ((DialogWindow)twoFactorView).Show();
+                //twoFactorView.ViewModel = twoFactorDialog;
+                //((DialogWindow)twoFactorView).Show();
 
                 var userError = new TwoFactorRequiredUserError(exception);
                 return twoFactorDialog.Show(userError)
@@ -37,8 +39,9 @@ namespace GitHub.Authentication
                             : Observable.Throw<TwoFactorChallengeResult>(exception));
             }, RxApp.MainThreadScheduler)
             .SelectMany(x => x)
-            .Finally(() =>
-                ((DialogWindow)twoFactorView).Hide());
+            //.Finally(() =>
+            //    ((DialogWindow)twoFactorView).Hide());
+            ;
         }
     }
 }