Slideshow update thread removed in favor of Rx

Will want to replace the throttle /w a debounce call.
Also will want to remove unnecessary subject once command IsExecuting callbacks are researched

Wabbajack/AppState.cs

@@ -22,18 +22,17 @@ using Wabbajack.NexusApi;
 using Wabbajack.UI;
 using DynamicData;
 using DynamicData.Binding;
+using System.Reactive;
 
 namespace Wabbajack
 {
     public enum TaskMode { INSTALLING, BUILDING }
-    internal class AppState : ViewModel, IDataErrorInfo
+    public class AppState : ViewModel, IDataErrorInfo
     {
         public const bool GcCollect = true;
 
         private SlideShow _slideShow;
 
-        public bool installing = false;
-
         private string _mo2Folder;
 
         private readonly BitmapImage _wabbajackLogo = UIUtils.BitmapImageFromResource("Wabbajack.UI.banner.png");
@@ -69,6 +68,9 @@ namespace Wabbajack
         private string _HTMLReport;
         public string HTMLReport { get => _HTMLReport; set => this.RaiseAndSetIfChanged(ref _HTMLReport, value); }
 
+        private bool _Installing;
+        public bool Installing { get => _Installing; set => this.RaiseAndSetIfChanged(ref _Installing, value); }
+
         // Command properties
         public IReactiveCommand ChangePathCommand => ReactiveCommand.Create(ExecuteChangePath);
         public IReactiveCommand ChangeDownloadPathCommand => ReactiveCommand.Create(ExecuteChangeDownloadPath);
@@ -77,7 +79,10 @@ namespace Wabbajack
         public IReactiveCommand VisitNexusSiteCommand => ReactiveCommand.Create(VisitNexusSite);
         public IReactiveCommand OpenReadmeCommand { get; }
         public IReactiveCommand OpenModListPropertiesCommand => ReactiveCommand.Create(OpenModListProperties);
-        public IReactiveCommand SlideShowNextItemCommand { get; }
+        // ToDo
+        // This subject is not desirable.  Need to research why command's IsExecuting observable not firing, as we'd prefer to hook onto that instead
+        private Subject<Unit> _slideshowCommandTriggeredSubject = new Subject<Unit>();
+        public ReactiveCommand<Unit, Unit> SlideShowNextItemCommand => ReactiveCommand.Create(() => _slideshowCommandTriggeredSubject.OnNext(Unit.Default));
 
         public AppState()
         {
@@ -121,7 +126,6 @@ namespace Wabbajack
                 .DisposeWith(this.CompositeDisposable);
 
             _slideShow = new SlideShow(this, true);
-            this.SlideShowNextItemCommand = ReactiveCommand.Create(_slideShow.UpdateSlideShowItem);
 
             // Update splashscreen when modlist changes
             Observable.CombineLatest(
@@ -170,10 +174,24 @@ namespace Wabbajack
                 .Subscribe(bitmap => this.SplashScreenImage = bitmap)
                 .DisposeWith(this.CompositeDisposable);
 
-            // Trigger a slideshow update if enabled
+            /// Wire slideshow updates
-            this.WhenAny(x => x.EnableSlideShow)
+            // Merge all the sources that trigger a slideshow update
-                .Skip(1) // Don't fire initially
+            Observable.Merge(
-                .WhenAny(enable => enable)
+                    // If the natural timer fires
+                    Observable.Interval(TimeSpan.FromSeconds(10)).Unit(),
+                    // If user requests one manually
+                    _slideshowCommandTriggeredSubject)
+                // When enabled, fire an initial signal
+                .StartWith(Unit.Default)
+                // Only subscribe to slideshow triggers if enabled and installing
+                .FilterSwitch(
+                    Observable.CombineLatest(
+                        this.WhenAny(x => x.EnableSlideShow),
+                        this.WhenAny(x => x.Installing),
+                        resultSelector: (enabled, installing) => enabled && installing))
+                // Don't ever update more than once every half second.  ToDo: Update to debounce
+                .Throttle(TimeSpan.FromMilliseconds(500), RxApp.MainThreadScheduler)
+                .ObserveOn(RxApp.MainThreadScheduler)
                 .Subscribe(_ => _slideShow.UpdateSlideShowItem())
                 .DisposeWith(this.CompositeDisposable);
 
@@ -192,17 +210,8 @@ namespace Wabbajack
                 .Bind(this.Status)
                 .Subscribe()
                 .DisposeWith(this.CompositeDisposable);
-
-            slideshowThread = new Thread(UpdateLoop)
-            {
-                Priority = ThreadPriority.BelowNormal,
-                IsBackground = true
-            };
-            slideshowThread.Start();
         }
 
-        public DateTime lastSlideShowUpdate = new DateTime();
-
         public ObservableCollection<string> Log { get; } = new ObservableCollection<string>();
 
         private string _Location;
@@ -317,7 +326,6 @@ namespace Wabbajack
         public string SplashScreenSummary { get => _SplashScreenSummary; set => this.RaiseAndSetIfChanged(ref _SplashScreenSummary, value); }
         private bool _splashShowNSFW = false;
         public bool SplashShowNSFW { get => _splashShowNSFW; set => this.RaiseAndSetIfChanged(ref _splashShowNSFW, value); }
-        private readonly Thread slideshowThread = null;
 
         public string Error => "Error";
 
@@ -355,23 +363,6 @@ namespace Wabbajack
             return validationMessage;
         }
 
-        private void UpdateLoop()
-        {
-            while (Running)
-            {
-                if (_slideShow.SlidesQueue.Any())
-                {
-                    if (DateTime.Now - lastSlideShowUpdate > TimeSpan.FromSeconds(10))
-                    {
-                        _slideShow.UpdateSlideShowItem();
-                    }
-                }
-                Thread.Sleep(1000);
-            }
-        }
-
-        public bool Running { get; set; } = true;
-
         public void LogMsg(string msg)
         {
             Application.Current.Dispatcher.Invoke(() => Log.Add(msg));
@@ -425,7 +416,7 @@ namespace Wabbajack
             UIReady = false;
             if (Mode == TaskMode.INSTALLING)
             {
-                installing = true;
+                this.Installing = true;
                 var installer = new Installer(this.ModListPath, this.ModList, Location)
                 {
                     DownloadFolder = DownloadLocation
@@ -447,9 +438,7 @@ namespace Wabbajack
                     finally
                     {
                         UIReady = true;
-                        Running = false;
+                        this.Installing = false;
-                        installing = false;
-                        slideshowThread.Abort();
                     }
                 })
                 {

Wabbajack/Extensions/ReactiveUIExt.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Linq;
 using System.Linq.Expressions;
+using System.Reactive;
 using System.Reactive.Linq;
 using DynamicData;
 using DynamicData.Kernel;
@@ -29,6 +30,38 @@ namespace Wabbajack
             return source.ObserveOn(RxApp.MainThreadScheduler);
         }
 
+        public static IObservable<Unit> Unit<T>(this IObservable<T> source)
+        {
+            return source.Select(_ => System.Reactive.Unit.Default);
+        }
+
+        /// <summary>
+        /// Convenience operator to subscribe to the source observable, only when a second "switch" observable is on.
+        /// When the switch is on, the source will be subscribed to, and its updates passed through.
+        /// When the switch is off, the subscription to the source observable will be stopped, and no signal will be published.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="source">Source observable to subscribe to if on</param>
+        /// <param name="filterSwitch">On/Off signal of whether to subscribe to source observable</param>
+        /// <returns>Observable that publishes data from source, if the switch is on.</returns>
+        public static IObservable<T> FilterSwitch<T>(this IObservable<T> source, IObservable<bool> filterSwitch)
+        {
+            return filterSwitch
+                .DistinctUntilChanged()
+                .Select(on =>
+                {
+                    if (on)
+                    {
+                        return source;
+                    }
+                    else
+                    {
+                        return Observable.Empty<T>();
+                    }
+                })
+                .Switch();
+        }
+
         /// These snippets were provided by RolandPheasant (author of DynamicData)
         /// They'll be going into the official library at some point, but are here for now.
         #region Dynamic Data EnsureUniqueChanges        

Wabbajack/UI/MainWindow.xaml

@@ -149,7 +149,7 @@
                         Height="30"
                         HorizontalAlignment="Right"
                         Command="{Binding SlideShowNextItemCommand}"
-                        ToolTip="Spamming this button will result in problems">
+                        ToolTip="Skip to next slide">
                         <DockPanel>
                             <Image Source="{Binding NextIcon}" Stretch="Fill" />
                         </DockPanel>

Wabbajack/UI/MainWindow.xaml.cs

@@ -68,7 +68,6 @@ namespace Wabbajack
                             MessageBoxImage.Error);
                         Dispatcher.Invoke(() =>
                         {
-                            context.Running = false;
                             ExitWhenClosing = false;
                             var window = new ModeSelectionWindow
                             {

Wabbajack/UI/SlideShow.cs

@@ -74,7 +74,7 @@ namespace Wabbajack.UI
 
         public void UpdateSlideShowItem()
         {
-            if (!_appState.EnableSlideShow || !_appState.installing || SlidesQueue.Count==0) return;
+            if (SlidesQueue.Count == 0) return;
             var slide = SlidesQueue.Peek();
 
             while (CachedSlides.Count >= MaxCacheSize)
@@ -98,11 +98,8 @@ namespace Wabbajack.UI
                 _appState.SplashScreenImage = _appState._noneImage;
                 if (slide.ImageURL != null && slide.Image != null)
                 {
-                    System.Windows.Application.Current.Dispatcher.Invoke(() =>
+                    if (!CachedSlides.ContainsKey(slide.ModID)) return;
-                    {
+                    _appState.SplashScreenImage = slide.Image;
-                        if (!CachedSlides.ContainsKey(slide.ModID)) return;
-                        _appState.SplashScreenImage = slide.Image;
-                    });
                 }
 
                 _appState.SplashScreenModName = slide.ModName;
@@ -111,8 +108,6 @@ namespace Wabbajack.UI
                 _appState._nexusSiteURL = slide.ModURL;
             }
 
-            _appState.lastSlideShowUpdate = DateTime.Now;
-
             SlidesQueue.Dequeue();
             QueueRandomSlide(false, true);
         }