Refactor command handlers and Startup

src/AppCommon/FileTime.App.Core/Services/CommandHandler/NavigationCommandHandler.cs

@@ -0,0 +1,71 @@
+using System.Reactive.Linq;
+using FileTime.App.Core.Command;
+using FileTime.App.Core.Extensions;
+using FileTime.App.Core.ViewModels;
+using FileTime.Core.Models;
+
+namespace FileTime.App.Core.Services.CommandHandler
+{
+    public class NavigationCommandHandler : CommandHanderBase
+    {
+        private readonly IAppState _appState;
+        private ITabViewModel? _selectedTab;
+        private IContainer? _currentLocation;
+        private IItemViewModel? _currentSelectedItem;
+        private List<IItemViewModel> _currentItems = new();
+
+        public NavigationCommandHandler(IAppState appState)
+        {
+            _appState = appState;
+
+            _appState.SelectedTab.Subscribe(t => _selectedTab = t);
+            _appState.SelectedTab.Select(t => t == null ? Observable.Return<IContainer?>(null) : t.CurrentLocation).Switch().Subscribe(l => _currentLocation = l);
+            _appState.SelectedTab.Select(t => t == null ? Observable.Return<IItemViewModel?>(null) : t.CurrentSelectedItem).Switch().Subscribe(l => _currentSelectedItem = l);
+            _appState.SelectedTab.Select(t => t == null ? Observable.Return(Enumerable.Empty<IItemViewModel>()) : t.CurrentItems).Switch().Subscribe(i => _currentItems = i.ToList());
+
+            AddCommandHandlers(new (Commands, Func<Task>)[]
+            {
+                (Commands.GoUp, GoUp),
+                (Commands.MoveCursorDown, MoveCursorDown),
+                (Commands.MoveCursorUp, MoveCursorUp),
+                (Commands.Open, OpenContainer),
+            });
+        }
+
+        private Task OpenContainer()
+        {
+            if (_currentSelectedItem is not IContainerViewModel containerViewModel || containerViewModel.Container is null) return Task.CompletedTask;
+
+            _selectedTab?.Tab?.SetCurrentLocation(containerViewModel.Container);
+            return Task.CompletedTask;
+        }
+
+        private async Task GoUp()
+        {
+            if (_currentLocation?.Parent is not IAbsolutePath parentPath || await parentPath.ResolveAsyncSafe() is not IContainer newContainer) return;
+            _selectedTab?.Tab?.SetCurrentLocation(newContainer);
+        }
+
+        private Task MoveCursorDown()
+        {
+            SelectNewSelectedItem(i => i.SkipWhile(i => i != _currentSelectedItem).Skip(1).FirstOrDefault());
+            return Task.CompletedTask;
+        }
+
+        private Task MoveCursorUp()
+        {
+            SelectNewSelectedItem(i => i.TakeWhile(i => i != _currentSelectedItem).LastOrDefault());
+            return Task.CompletedTask;
+        }
+
+        private void SelectNewSelectedItem(Func<IEnumerable<IItemViewModel>, IItemViewModel?> getNewSelected)
+        {
+            if (_selectedTab is null || _currentLocation is null) return;
+
+            var newSelectedItem = getNewSelected(_currentItems);
+            if (newSelectedItem == null) return;
+
+            _selectedTab.Tab?.SetSelectedItem(newSelectedItem.ToAbsolutePath());
+        }
+    }
+}