0.7.5.1

精致

LanMountainDesktop/ViewModels/ComponentLibraryWindowViewModel.cs

@@ -1,13 +1,21 @@
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using Avalonia.Controls;
+using System.ComponentModel;
+using LanMountainDesktop.Services;
 using FluentIcons.Common;
+using CommunityToolkit.Mvvm.ComponentModel;
 
 namespace LanMountainDesktop.ViewModels;
 
 public sealed class ComponentLibraryWindowViewModel : ViewModelBase
 {
-    public string Title { get; set; } = "Widgets";
+    private string _title = "Widgets";
+
+    public string Title
+    {
+        get => _title;
+        set => SetProperty(ref _title, value);
+    }
 
     public ObservableCollection<ComponentLibraryCategoryViewModel> Categories { get; } = [];
 
@@ -38,20 +46,134 @@ public sealed class ComponentLibraryCategoryViewModel
 }
 
 public sealed class ComponentLibraryItemViewModel
+    : ObservableObject
 {
+    private readonly string _loadingPreviewText;
+    private readonly string _previewUnavailableText;
+    private string _displayName;
+    private ComponentPreviewKey _previewKey;
+    private ComponentPreviewImageEntry? _previewImageEntry;
+    private ComponentPreviewImageState _previewState;
+    private string? _previewErrorMessage;
+    private string _previewStatusText;
+
     public ComponentLibraryItemViewModel(
         string componentId,
         string displayName,
-        Control? previewControl)
+        ComponentPreviewKey previewKey,
+        string loadingPreviewText = "Loading preview...",
+        string previewUnavailableText = "Preview unavailable",
+        ComponentPreviewImageEntry? previewImageEntry = null)
     {
         ComponentId = componentId;
-        DisplayName = displayName;
-        PreviewControl = previewControl;
+        _displayName = displayName;
+        _previewKey = previewKey;
+        _loadingPreviewText = loadingPreviewText;
+        _previewUnavailableText = previewUnavailableText;
+        _previewStatusText = loadingPreviewText;
+        UpdatePreviewImageEntry(previewImageEntry, raiseEntryChanged: false);
     }
 
     public string ComponentId { get; }
 
-    public string DisplayName { get; }
+    public string DisplayName
+    {
+        get => _displayName;
+        set => SetProperty(ref _displayName, value);
+    }
 
-    public Control? PreviewControl { get; }
+    public ComponentPreviewKey PreviewKey
+    {
+        get => _previewKey;
+        set => SetProperty(ref _previewKey, value);
+    }
+
+    public ComponentPreviewImageEntry? PreviewImageEntry => _previewImageEntry;
+
+    public object? PreviewBitmap => _previewImageEntry?.Bitmap;
+
+    public ComponentPreviewImageState PreviewState => _previewState;
+
+    public bool IsPreviewPending => _previewState == ComponentPreviewImageState.Pending;
+
+    public bool IsPreviewReady => _previewState == ComponentPreviewImageState.Ready && _previewImageEntry?.Bitmap is not null;
+
+    public bool IsPreviewFailed => _previewState == ComponentPreviewImageState.Failed;
+
+    public string? PreviewErrorMessage => _previewErrorMessage;
+
+    public string PreviewStatusText => _previewStatusText;
+
+    public void UpdatePreviewImageEntry(ComponentPreviewImageEntry? previewImageEntry)
+    {
+        UpdatePreviewImageEntry(previewImageEntry, raiseEntryChanged: true);
+    }
+
+    private void UpdatePreviewImageEntry(ComponentPreviewImageEntry? previewImageEntry, bool raiseEntryChanged)
+    {
+        if (raiseEntryChanged && ReferenceEquals(_previewImageEntry, previewImageEntry))
+        {
+            return;
+        }
+
+        if (_previewImageEntry is not null)
+        {
+            _previewImageEntry.PropertyChanged -= OnPreviewImageEntryPropertyChanged;
+        }
+
+        _previewImageEntry = previewImageEntry;
+        _previewState = previewImageEntry?.State ?? ComponentPreviewImageState.Pending;
+        _previewErrorMessage = previewImageEntry?.ErrorMessage;
+
+        _previewStatusText = _previewState switch
+        {
+            ComponentPreviewImageState.Ready => string.Empty,
+            ComponentPreviewImageState.Failed => string.IsNullOrWhiteSpace(_previewErrorMessage)
+                ? _previewUnavailableText
+                : _previewErrorMessage!,
+            _ => _loadingPreviewText
+        };
+
+        if (_previewImageEntry is not null)
+        {
+            _previewImageEntry.PropertyChanged += OnPreviewImageEntryPropertyChanged;
+        }
+
+        RaisePreviewDependentProperties();
+    }
+
+    private void OnPreviewImageEntryPropertyChanged(object? sender, PropertyChangedEventArgs e)
+    {
+        _ = sender;
+        if (string.IsNullOrWhiteSpace(e.PropertyName) ||
+            e.PropertyName is nameof(ComponentPreviewImageEntry.Bitmap) or
+                nameof(ComponentPreviewImageEntry.State) or
+                nameof(ComponentPreviewImageEntry.ErrorMessage))
+        {
+            _previewState = _previewImageEntry?.State ?? ComponentPreviewImageState.Pending;
+            _previewErrorMessage = _previewImageEntry?.ErrorMessage;
+            _previewStatusText = _previewState switch
+            {
+                ComponentPreviewImageState.Ready => string.Empty,
+                ComponentPreviewImageState.Failed => string.IsNullOrWhiteSpace(_previewErrorMessage)
+                    ? _previewUnavailableText
+                    : _previewErrorMessage!,
+                _ => _loadingPreviewText
+            };
+
+            RaisePreviewDependentProperties();
+        }
+    }
+
+    private void RaisePreviewDependentProperties()
+    {
+        OnPropertyChanged(nameof(PreviewImageEntry));
+        OnPropertyChanged(nameof(PreviewBitmap));
+        OnPropertyChanged(nameof(PreviewState));
+        OnPropertyChanged(nameof(IsPreviewPending));
+        OnPropertyChanged(nameof(IsPreviewReady));
+        OnPropertyChanged(nameof(IsPreviewFailed));
+        OnPropertyChanged(nameof(PreviewErrorMessage));
+        OnPropertyChanged(nameof(PreviewStatusText));
+    }
 }