Add editor simulation playback

src/ReactorMaintenance.Win2D/MainWindow.xaml

@@ -15,7 +15,8 @@
             <AppBarButton Icon="OpenFile" Label="Open" Click="Open_Click" />
             <AppBarButton Icon="Save" Label="Save" Click="Save_Click" />
             <AppBarSeparator />
-            <AppBarButton Icon="Play" Label="End Turn" Click="EndTurn_Click" />
+            <AppBarButton x:Name="PlayPauseButton" Icon="Play" Label="Play" Click="PlayPause_Click" />
+            <AppBarButton Icon="Forward" Label="End Turn" Click="EndTurn_Click" />
             <AppBarButton Label="Interact" Click="Interact_Click" />
             <AppBarButton Label="Heat Shield" Click="HeatShield_Click" />
             <AppBarButton Icon="Accept" Label="Activate" Click="Activate_Click" />

src/ReactorMaintenance.Win2D/MainWindow.xaml.cs

@@ -81,10 +81,13 @@ public sealed partial class MainWindow
 
         m_Level = BuildStarterLevel();
         m_EditorTools = BuildEditorTools();
+        m_SimulationTimer.Interval = TimeSpan.FromSeconds(1.0 / c_SimulationStepsPerSecond);
+        m_SimulationTimer.Tick += SimulationTimer_Tick;
         LayerPicker.ItemsSource = Enum.GetValues<EEditorLayer>();
         LayerPicker.SelectedItem = EEditorLayer.Surface;
         RefreshToolPicker();
         RefreshInspector();
+        UpdatePlayPauseButton();
     }
 
     private void LevelCanvas_CreateResources(CanvasControl sender, CanvasCreateResourcesEventArgs args)
@@ -147,6 +150,7 @@ public sealed partial class MainWindow
 
     private void New_Click(object sender, RoutedEventArgs e)
     {
+        StopSimulationTimer();
         m_Level = BuildStarterLevel();
         m_CurrentFile = null;
         m_SelectedCell = null;
@@ -166,6 +170,7 @@ public sealed partial class MainWindow
             if (file is null)
                 return;
 
+            StopSimulationTimer();
             var json = await FileIO.ReadTextAsync(file);
             var loaded = LevelSerializer.Deserialize(json);
             m_Level = loaded with { Forecasts = m_Simulation.Forecast(loaded) };
@@ -213,6 +218,43 @@ public sealed partial class MainWindow
     }
 
     private void EndTurn_Click(object sender, RoutedEventArgs e)
+    {
+        RunSimulationStep();
+    }
+
+    private void PlayPause_Click(object sender, RoutedEventArgs e)
+    {
+        if (m_SimulationTimer.IsEnabled)
+            StopSimulationTimer();
+        else
+            StartSimulationTimer();
+    }
+
+    private void SimulationTimer_Tick(object? sender, object e)
+    {
+        RunSimulationStep();
+    }
+
+    private void StartSimulationTimer()
+    {
+        m_SimulationTimer.Start();
+        UpdatePlayPauseButton();
+    }
+
+    private void StopSimulationTimer()
+    {
+        m_SimulationTimer.Stop();
+        UpdatePlayPauseButton();
+    }
+
+    private void UpdatePlayPauseButton()
+    {
+        var isPlaying = m_SimulationTimer.IsEnabled;
+        PlayPauseButton.Icon = new SymbolIcon(isPlaying ? Symbol.Pause : Symbol.Play);
+        PlayPauseButton.Label = isPlaying ? "Pause" : "Play";
+    }
+
+    private void RunSimulationStep()
     {
         m_Level = m_Simulation.EndTurn(m_Level);
         RefreshInspector();
@@ -1313,6 +1355,7 @@ public sealed partial class MainWindow
     private const double c_MaxZoom = 4;
     private const double c_ZoomStep = 1.15;
     private const double c_ClickPixelThreshold = 10;
+    private const int c_SimulationStepsPerSecond = 2;
     private const int c_TilemapTileSize = 512;
     private const int c_TopLeftCorner = 1;
     private const int c_TopRightCorner = 2;
@@ -1326,6 +1369,7 @@ public sealed partial class MainWindow
     private readonly EditorImageRegistry m_Images = new();
 
     private readonly SimulationEngine m_Simulation = new();
+    private readonly DispatcherTimer m_SimulationTimer = new();
     private EEditorLayer m_ActiveLayer = EEditorLayer.Surface;
     private StorageFile? m_CurrentFile;
     private GridPosition? m_CursorDragStartCell;