feat: implement asynchronous asset management system with texture streaming support

src/Editor/Ghost.Editor/Views/Controls/Docking/DockGroup.cs

@@ -0,0 +1,182 @@
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Controls;
+using Microsoft.UI.Xaml.Data;
+
+namespace Ghost.Editor.Views.Controls.Docking;
+
+/// <summary>
+/// A container that displays its children (documents) as tabs.
+/// </summary>
+[TemplatePart(Name = PART_TAB_VIEW, Type = typeof(TabView))]
+public partial class DockGroup : DockContainer
+{
+    private const string PART_TAB_VIEW = "PART_TabView";
+    private const string DRAG_DOCUMENT_KEY = "DockDocument";
+    private TabView? _tabView;
+
+    public DockGroup()
+    {
+        DefaultStyleKey = typeof(DockGroup);
+    }
+
+    protected override void ValidateChild(DockModule module)
+    {
+        base.ValidateChild(module);
+
+        if (module is not DockDocument)
+        {
+            throw new ArgumentException($"{nameof(DockGroup)} only accepts {nameof(DockDocument)} children.", nameof(module));
+        }
+    }
+
+    protected override void OnApplyTemplate()
+    {
+        base.OnApplyTemplate();
+
+        if (_tabView != null)
+        {
+            _tabView.TabDragStarting -= OnTabDragStarting;
+            _tabView.TabDroppedOutside -= OnTabDroppedOutside;
+            _tabView.DragOver -= OnDragOver;
+            _tabView.Drop -= OnDrop;
+            _tabView.DragLeave -= OnDragLeave;
+            _tabView.TabCloseRequested -= OnTabCloseRequested;
+        }
+
+        _tabView = GetTemplateChild(PART_TAB_VIEW) as TabView;
+
+        if (_tabView != null)
+        {
+            _tabView.TabDragStarting += OnTabDragStarting;
+            _tabView.TabDroppedOutside += OnTabDroppedOutside;
+            _tabView.DragOver += OnDragOver;
+            _tabView.Drop += OnDrop;
+            _tabView.DragLeave += OnDragLeave;
+            _tabView.TabCloseRequested += OnTabCloseRequested;
+        }
+
+        UpdateTabs();
+    }
+
+    private void OnTabDragStarting(TabView sender, TabViewTabDragStartingEventArgs args)
+    {
+        if (args.Tab.Tag is DockDocument doc)
+        {
+            args.Data.Properties.Add(DRAG_DOCUMENT_KEY, doc);
+        }
+    }
+
+    private void OnTabDroppedOutside(TabView sender, TabViewTabDroppedOutsideEventArgs args)
+    {
+        if (args.Tab.Tag is DockDocument doc)
+        {
+            Root?.CreateFloatingWindow(doc);
+        }
+    }
+
+    private void OnDragOver(object sender, DragEventArgs e)
+    {
+        if (e.DataView.Properties.ContainsKey(DRAG_DOCUMENT_KEY))
+        {
+            e.AcceptedOperation = global::Windows.ApplicationModel.DataTransfer.DataPackageOperation.Move;
+            Root?.ShowHighlight(this, e.GetPosition(this));
+        }
+    }
+
+    private void OnDrop(object sender, DragEventArgs e)
+    {
+        if (e.DataView.Properties.TryGetValue(DRAG_DOCUMENT_KEY, out var obj) && obj is DockDocument doc)
+        {
+            Root?.HandleDrop(doc, this, e.GetPosition(this));
+        }
+    }
+
+    private void OnDragLeave(object sender, DragEventArgs e)
+    {
+        Root?.HideHighlight();
+    }
+
+    private void OnTabCloseRequested(TabView sender, TabViewTabCloseRequestedEventArgs args)
+    {
+        if (args.Tab.Tag is DockDocument doc)
+        {
+            RemoveChild(doc);
+        }
+    }
+
+    protected override void OnChildrenUpdated()
+    {
+        UpdateTabs();
+    }
+
+    private void UpdateTabs()
+    {
+        if (_tabView == null || Root == null) return;
+
+        var selectedDoc = _tabView.SelectedItem is TabViewItem selectedItem ? selectedItem.Tag as DockDocument : null;
+
+        // Remove tabs that are no longer in Children
+        for (int i = _tabView.TabItems.Count - 1; i >= 0; i--)
+        {
+            if (_tabView.TabItems[i] is TabViewItem tabItem && tabItem.Tag is DockDocument doc)
+            {
+                if (!Children.Contains(doc))
+                {
+                    tabItem.Content = null;
+                    _tabView.TabItems.RemoveAt(i);
+                }
+            }
+        }
+
+        // Add new tabs that aren't in TabItems yet, and ensure correct order
+        for (int i = 0; i < Children.Count; i++)
+        {
+            if (Children[i] is DockDocument doc)
+            {
+                TabViewItem? existingTab = null;
+                for (int j = 0; j < _tabView.TabItems.Count; j++)
+                {
+                    if (_tabView.TabItems[j] is TabViewItem tabItem && tabItem.Tag == doc)
+                    {
+                        existingTab = tabItem;
+                        // Fix order if necessary
+                        if (j != i)
+                        {
+                            _tabView.TabItems.RemoveAt(j);
+                            _tabView.TabItems.Insert(i, existingTab);
+                        }
+                        break;
+                    }
+                }
+
+                if (existingTab == null)
+                {
+                    existingTab = new TabViewItem
+                    {
+                        Tag = doc,
+                        Content = doc
+                    };
+
+                    existingTab.SetBinding(TabViewItem.HeaderProperty, new Binding
+                    {
+                        Source = doc,
+                        Path = new PropertyPath(nameof(DockDocument.Title)),
+                        Mode = Microsoft.UI.Xaml.Data.BindingMode.OneWay
+                    });
+
+                    _tabView.TabItems.Insert(i, existingTab);
+                }
+            }
+        }
+
+        // Restore selection
+        if (selectedDoc != null && _tabView.TabItems.FirstOrDefault(t => t is TabViewItem item && item.Tag == selectedDoc) is TabViewItem newSelected)
+        {
+            _tabView.SelectedItem = newSelected;
+        }
+        else if (_tabView.TabItems.Count > 0)
+        {
+            _tabView.SelectedItem = _tabView.TabItems[0];
+        }
+    }
+}