Added Scheduler for Terminal (#103)

Author: ChrisPulman

src/ReactiveMvvm.Terminal/Program.cs

@@ -1,8 +1,10 @@
 using System;
+using System.Reactive.Concurrency;
 using ReactiveMvvm.Services;
 using ReactiveMvvm.Terminal.Services;
 using ReactiveMvvm.Terminal.Views;
 using ReactiveMvvm.ViewModels;
+using ReactiveUI;
 using Terminal.Gui;
 
 namespace ReactiveMvvm.Terminal
@@ -12,6 +14,8 @@ public static class Program
         public static void Main(string[] args)
         {
             Application.Init();
+            RxApp.MainThreadScheduler = TerminalScheduler.Default;
+            RxApp.TaskpoolScheduler = TaskPoolScheduler.Default;
             Application.Run(
                 new FeedbackView(
                     new(

src/ReactiveMvvm.Terminal/TerminalScheduler.cs

@@ -0,0 +1,60 @@
+using System;
+using System.Reactive.Concurrency;
+using System.Reactive.Disposables;
+using Terminal.Gui;
+
+namespace ReactiveMvvm;
+
+public class TerminalScheduler : LocalScheduler
+{
+    public static readonly TerminalScheduler Default = new ();
+    private TerminalScheduler () { }
+
+    public override IDisposable Schedule<TState> (
+        TState state,
+        TimeSpan dueTime,
+        Func<IScheduler, TState, IDisposable> action
+    )
+    {
+        IDisposable PostOnMainLoop ()
+        {
+            var composite = new CompositeDisposable (2);
+            var cancellation = new CancellationDisposable ();
+
+            Application.Invoke (
+                                () =>
+                                {
+                                    if (!cancellation.Token.IsCancellationRequested)
+                                    {
+                                        composite.Add (action (this, state));
+                                    }
+                                }
+                               );
+            composite.Add (cancellation);
+
+            return composite;
+        }
+
+        IDisposable PostOnMainLoopAsTimeout ()
+        {
+            var composite = new CompositeDisposable (2);
+
+            object timeout = Application.AddTimeout (
+                                                     dueTime,
+                                                     () =>
+                                                     {
+                                                         composite.Add (action (this, state));
+
+                                                         return false;
+                                                     }
+                                                    );
+            composite.Add (Disposable.Create (() => Application.RemoveTimeout (timeout)));
+
+            return composite;
+        }
+
+        return dueTime == TimeSpan.Zero
+                   ? PostOnMainLoop ()
+                   : PostOnMainLoopAsTimeout ();
+    }
+}