feat: Create a new GUI project based on Avalonia. (Powered by Claude)

src/ZonyLrcTools.Desktop/Services/NavigationService.cs

@@ -0,0 +1,50 @@
+using Microsoft.Extensions.DependencyInjection;
+using ZonyLrcTools.Desktop.ViewModels;
+
+namespace ZonyLrcTools.Desktop.Services;
+
+public class NavigationService : INavigationService
+{
+    private readonly IServiceProvider _serviceProvider;
+    private readonly Stack<ViewModelBase> _navigationStack = new();
+
+    public ViewModelBase? CurrentViewModel => _navigationStack.TryPeek(out var vm) ? vm : null;
+    public bool CanGoBack => _navigationStack.Count > 1;
+
+    public event EventHandler<ViewModelBase>? NavigationChanged;
+
+    public NavigationService(IServiceProvider serviceProvider)
+    {
+        _serviceProvider = serviceProvider;
+    }
+
+    public TViewModel NavigateTo<TViewModel>() where TViewModel : ViewModelBase
+    {
+        var viewModel = _serviceProvider.GetRequiredService<TViewModel>();
+
+        if (_navigationStack.TryPeek(out var current))
+        {
+            _ = current.OnDeactivatedAsync();
+        }
+
+        _navigationStack.Push(viewModel);
+        _ = viewModel.OnActivatedAsync();
+
+        NavigationChanged?.Invoke(this, viewModel);
+        return viewModel;
+    }
+
+    public void GoBack()
+    {
+        if (!CanGoBack) return;
+
+        var current = _navigationStack.Pop();
+        _ = current.OnDeactivatedAsync();
+
+        if (_navigationStack.TryPeek(out var previous))
+        {
+            _ = previous.OnActivatedAsync();
+            NavigationChanged?.Invoke(this, previous);
+        }
+    }
+}