refactor ThemeSelectorBase and ThemeToggleButton

src/Ursa/Controls/ThemeSelector/ThemeSelectorBase.cs

@@ -10,7 +10,6 @@ public abstract class ThemeSelectorBase: TemplatedControl
 {
     private bool _syncFromScope;
     private Application? _application;
-    private ThemeVariantScope? _scope;
     
     public static readonly StyledProperty<ThemeVariant?> SelectedThemeProperty = AvaloniaProperty.Register<ThemeSelectorBase, ThemeVariant?>(
         nameof(SelectedTheme));
@@ -62,18 +61,12 @@ public abstract class ThemeSelectorBase: TemplatedControl
     private void OnScopeThemeChanged(object? sender, System.EventArgs e)
     {
         _syncFromScope = true;
-        if (this.TargetScope is { } target)
+        if (TargetScope is { } target)
         {
             SyncThemeFromScope(Mode == ThemeSelectorMode.Controller
                 ? target.RequestedThemeVariant
                 : target.ActualThemeVariant);
         }
-        else if (this._scope is { } scope)
-        {
-            SyncThemeFromScope(Mode == ThemeSelectorMode.Controller
-                ? scope.RequestedThemeVariant
-                : scope.ActualThemeVariant);
-        }
         else if (_application is { } app)
         {
             SyncThemeFromScope(Mode == ThemeSelectorMode.Controller
@@ -85,7 +78,7 @@ public abstract class ThemeSelectorBase: TemplatedControl
 
     protected virtual void SyncThemeFromScope(ThemeVariant? theme)
     {
-        this.SelectedTheme = theme;
+        SelectedTheme = theme;
     }
 
     protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
@@ -93,27 +86,30 @@ public abstract class ThemeSelectorBase: TemplatedControl
         base.OnAttachedToVisualTree(e);
         _application = Application.Current;
         _syncFromScope = true;
-        if (_application is not null)
+
+        if (TargetScope is not null)
+        {
+            TargetScope.ActualThemeVariantChanged += OnScopeThemeChanged;
+            SyncThemeFromScope(Mode == ThemeSelectorMode.Controller
+                ? TargetScope.RequestedThemeVariant
+                : TargetScope.ActualThemeVariant);
+        }
+        else if (this.GetLogicalAncestors().FirstOrDefault(a => a is ThemeVariantScope) is ThemeVariantScope scope)
+        {
+            TargetScope = scope;
+            TargetScope.ActualThemeVariantChanged += OnScopeThemeChanged;
+            SyncThemeFromScope(Mode == ThemeSelectorMode.Controller
+                ? TargetScope.RequestedThemeVariant
+                : TargetScope.ActualThemeVariant);
+        }
+        else if (_application is not null)
         {
             _application.ActualThemeVariantChanged += OnScopeThemeChanged;
             SyncThemeFromScope(Mode == ThemeSelectorMode.Controller
                 ? _application.RequestedThemeVariant
                 : _application.ActualThemeVariant);
         }
-        _scope = this.GetLogicalAncestors().FirstOrDefault(a => a is ThemeVariantScope) as ThemeVariantScope;
+
-        if (_scope is not null)
-        {
-            _scope.ActualThemeVariantChanged += OnScopeThemeChanged;
-            SyncThemeFromScope(Mode == ThemeSelectorMode.Controller
-                ? _scope.RequestedThemeVariant
-                : _scope.ActualThemeVariant);
-        }
-        if (TargetScope is not null)
-        {
-            SyncThemeFromScope(Mode == ThemeSelectorMode.Controller
-                ? TargetScope.RequestedThemeVariant
-                : TargetScope.ActualThemeVariant);
-        }
         _syncFromScope = false;
     }
 
@@ -124,9 +120,10 @@ public abstract class ThemeSelectorBase: TemplatedControl
         {
             _application.ActualThemeVariantChanged -= OnScopeThemeChanged;
         }
-        if (_scope is not null)
+
+        if (TargetScope is not null)
         {
-            _scope.ActualThemeVariantChanged -= OnScopeThemeChanged;
+            TargetScope.ActualThemeVariantChanged -= OnScopeThemeChanged;
         }
     }
 
@@ -139,11 +136,7 @@ public abstract class ThemeSelectorBase: TemplatedControl
             TargetScope.RequestedThemeVariant = newTheme;
             return;
         }
-        if (_scope is not null)
+
-        {
-            _scope.RequestedThemeVariant = newTheme;
-            return;
-        }
         if (_application is not null)
         {
             _application.RequestedThemeVariant = newTheme;

src/Ursa/Controls/ThemeSelector/ThemeToggleButton.cs

@@ -41,57 +41,50 @@ public class ThemeToggleButton: ThemeSelectorBase
 
     private void OnButtonClicked(object? sender, RoutedEventArgs e)
     {
-        bool? currentState = _state;
+        if (Mode == ThemeSelectorMode.Indicator || !IsThreeState)
-        if (IsThreeState)
         {
-            _state = currentState switch
+            _state = _state switch
-            {
-                true => false,
-                false => null,
-                null => true,
-            };
-        }
-        else
-        {
-            _state = currentState switch
             {
                 true => false,
                 false => true,
-                null => true,
+                null => throw new InvalidOperationException("Invalid state")
             };
         } 
-        if (_state == true)
-        {
-            SelectedTheme = ThemeVariant.Light;
-        }
-        else if (_state == false)
-        {
-            SelectedTheme = ThemeVariant.Dark;
-        }
         else
         {
-            SelectedTheme = ThemeVariant.Default;
+            _state = _state switch
+            {
+                true => false,
+                false => null,
+                null => true
+            };
         }
         
-        if (Mode == ThemeSelectorMode.Controller)
+        SelectedTheme = _state switch
         {
-            PseudoClasses.Set(PC_Light, SelectedTheme == ThemeVariant.Light);
+            true => ThemeVariant.Light,
-            PseudoClasses.Set(PC_Dark, SelectedTheme == ThemeVariant.Dark);
+            false => ThemeVariant.Dark,
-            PseudoClasses.Set(PC_Default, SelectedTheme == null || SelectedTheme == ThemeVariant.Default);
+            null => ThemeVariant.Default
-        }
+        };
+        
+        PseudoClasses.Set(PC_Light, SelectedTheme == ThemeVariant.Light);
+        PseudoClasses.Set(PC_Dark, SelectedTheme == ThemeVariant.Dark);
+        PseudoClasses.Set(PC_Default, SelectedTheme == ThemeVariant.Default);
     }
 
     protected override void SyncThemeFromScope(ThemeVariant? theme)
     {
         base.SyncThemeFromScope(theme);
-        if (Mode == ThemeSelectorMode.Indicator)
+        if (!IsThreeState && theme is null)
         {
-            PseudoClasses.Set(PC_Light, theme == ThemeVariant.Light);
+            theme = ThemeVariant.Light;
-            PseudoClasses.Set(PC_Dark, theme == ThemeVariant.Dark);
-            PseudoClasses.Set(PC_Default, theme == null || SelectedTheme == ThemeVariant.Default);
-            if (theme == ThemeVariant.Dark) _state = false;
-            else if (theme == ThemeVariant.Light) _state = true;
-            else _state = null;
         }
+        
+        PseudoClasses.Set(PC_Light, theme == ThemeVariant.Light);
+        PseudoClasses.Set(PC_Dark, theme == ThemeVariant.Dark);
+        PseudoClasses.Set(PC_Default, theme == null || SelectedTheme == ThemeVariant.Default);
+        if (theme == ThemeVariant.Dark) _state = false;
+        else if (theme == ThemeVariant.Light) _state = true;
+        else _state = null;
     }
 }