feat: add pseudo classes.

src/Ursa/Controls/NavMenu/NavMenuItem.cs

@@ -11,12 +11,17 @@ using Avalonia.VisualTree;
 
 namespace Ursa.Controls;
 
-[PseudoClasses(PC_Highlighted)]
+[PseudoClasses(PC_Highlighted, PC_Collapsed, PC_Closed, PC_FirstLevel, PC_Selector)]
 public class NavMenuItem: HeaderedSelectingItemsControl
 {
-    public const string PC_Highlighted = "highlighted";
+    public const string PC_Highlighted = ":highlighted";
+    public const string PC_FirstLevel = ":first-level";
+    public const string PC_Collapsed = ":collapsed";
+    public const string PC_Closed = ":closed";
+    public const string PC_Selector = ":selector";
     
     private NavMenu? _rootMenu;
+    private Panel? _popupPanel;
     
     public static readonly StyledProperty<object?> IconProperty = AvaloniaProperty.Register<NavMenuItem, object?>(
         nameof(Icon));
@@ -36,8 +41,7 @@ public class NavMenuItem: HeaderedSelectingItemsControl
         set => SetValue(IconTemplateProperty, value);
     }
 
-    public static readonly StyledProperty<ICommand?> CommandProperty = AvaloniaProperty.Register<NavMenuItem, ICommand?>(
-        nameof(Command));
+    public static readonly StyledProperty<ICommand?> CommandProperty = Button.CommandProperty.AddOwner<NavMenuItem>();
 
     public ICommand? Command
     {
@@ -45,6 +49,15 @@ public class NavMenuItem: HeaderedSelectingItemsControl
         set => SetValue(CommandProperty, value);
     }
 
+    public static readonly StyledProperty<object?> CommandParameterProperty =
+        Button.CommandParameterProperty.AddOwner<NavMenuItem>();
+
+    public object? CommandParameter
+    {
+        get => GetValue(CommandParameterProperty);
+        set => SetValue(CommandParameterProperty, value);
+    }
+
     public new static readonly StyledProperty<bool> IsSelectedProperty =
         SelectingItemsControl.IsSelectedProperty.AddOwner<NavMenuItem>();
 
@@ -53,15 +66,34 @@ public class NavMenuItem: HeaderedSelectingItemsControl
         get => GetValue(IsSelectedProperty);
         set => SetValue(IsSelectedProperty, value);
     }
+
+    private bool _isHighlighted;
+
+    public static readonly DirectProperty<NavMenuItem, bool> IsHighlightedProperty = AvaloniaProperty.RegisterDirect<NavMenuItem, bool>(
+        nameof(IsHighlighted), o => o.IsHighlighted, (o, v) => o.IsHighlighted = v);
+
+    public bool IsHighlighted
+    {
+        get => _isHighlighted;
+        private set => SetAndRaise(IsHighlightedProperty, ref _isHighlighted, value);
+    }
     
     
+    internal int Level { get; set; }
+    
 
     static NavMenuItem()
     {
         SelectableMixin.Attach<NavMenuItem>(IsSelectedProperty);
         PressedMixin.Attach<NavMenuItem>();
+        IsHighlightedProperty.Changed.AddClassHandler<NavMenuItem, bool>((o, e) => o.OnIsHighlightedChange(e));
     }
-    
+
+    private void OnIsHighlightedChange(AvaloniaPropertyChangedEventArgs<bool> args)
+    {
+        PseudoClasses.Set(PC_Highlighted, args.NewValue.Value);
+    }
+
     protected override bool NeedsContainerOverride(object? item, int index, out object? recycleKey)
     {
         return NeedsContainer<NavMenuItem>(item, out recycleKey);
@@ -81,6 +113,18 @@ public class NavMenuItem: HeaderedSelectingItemsControl
             {
                 container[!HeaderProperty] = _rootMenu.HeaderBinding;
             }
+            if (_rootMenu?.IconBinding is not null)
+            {
+                container[!IconProperty] = _rootMenu.IconBinding;
+            }
+            if (_rootMenu?.SubMenuBinding is not null)
+            {
+                container[!ItemsSourceProperty] = _rootMenu.SubMenuBinding;
+            }
+            if (_rootMenu?.CommandBinding is not null)
+            {
+                container[!CommandProperty] = _rootMenu.CommandBinding;
+            }
         }
     }
 
@@ -90,16 +134,76 @@ public class NavMenuItem: HeaderedSelectingItemsControl
         _rootMenu = GetRootMenu();
     }
 
+    protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
+    {
+        var children = this.ItemsPanelRoot?.Children.ToList();
+        base.OnApplyTemplate(e);
+        Level = CalculateDistanceFromLogicalParent<NavMenuItem>(this);
+        PseudoClasses.Set(PC_FirstLevel, Level == 0);
+    }
+
     protected override void OnPointerPressed(PointerPressedEventArgs e)
     {
         base.OnPointerPressed(e);
-        _rootMenu?.SelectItem(this);
+        SelectItem(this);
+        Command?.Execute(CommandParameter);
         e.Handled = true;
     }
+    
+    protected void SelectItem(NavMenuItem item)
+    {
+        if (item == this)
+        {
+            SetCurrentValue(IsSelectedProperty, true);
+            SetCurrentValue(IsHighlightedProperty, true);
+        }
+        else
+        {
+            SetCurrentValue(IsSelectedProperty, false);
+            SetCurrentValue(IsHighlightedProperty, true);
+        }
+        if (this.Parent is NavMenuItem menuItem)
+        {
+            menuItem.SelectItem(item);
+        }
+        else if (this.Parent is NavMenu menu)
+        {
+            menu.SelectItem(item, this);
+        }
+    }
+
+    internal void ClearSelection()
+    {
+        SetCurrentValue(IsHighlightedProperty, false);
+        SetCurrentValue(IsSelectedProperty, false);
+        foreach (var child in LogicalChildren)
+        {
+            if (child is NavMenuItem item)
+            {
+                item.ClearSelection();
+            }
+        }
+    }
 
     private NavMenu? GetRootMenu()
     {
         var root = this.FindAncestorOfType<NavMenu>() ?? this.FindLogicalAncestorOfType<NavMenu>();
         return root;
     }
+    
+    private static int CalculateDistanceFromLogicalParent<T>(ILogical? logical, int @default = -1) where T : class
+    {
+        var result = 0;
+
+        while (logical != null && !(logical is T))
+        {
+            if (logical is NavMenuItem)
+            {
+                result++;
+            }
+            logical = logical.LogicalParent;
+        }
+
+        return logical != null ? result : @default;
+    }
 }