Added functionality for left/right key navigation (#5067)

* Added functionality for left/right key navigation

* Update Behviour of left/right navigation

* Code cleanup

* Null check for results VM

* Added tests for results view model

* Update test namings

src/modules/launcher/PowerLauncher/MainWindow.xaml.cs

@@ -239,6 +239,25 @@ namespace PowerLauncher
                 UpdateTextBoxToSelectedItem();
                 e.Handled = true;
             }
+            else if (e.Key == Key.Right)
+            {
+                if(SearchBox.QueryTextBox.CaretIndex == SearchBox.QueryTextBox.Text.Length)
+                {
+                    _viewModel.SelectNextContextMenuItemCommand.Execute(null);
+                    e.Handled = true;
+                }
+            }
+            else if (e.Key == Key.Left)
+            {
+                if (SearchBox.QueryTextBox.CaretIndex == SearchBox.QueryTextBox.Text.Length)
+                {
+                    if(_viewModel.Results != null && _viewModel.Results.IsContextMenuItemSelected())
+                    {
+                        _viewModel.SelectPreviousContextMenuItemCommand.Execute(null);
+                        e.Handled = true;
+                    }
+                }
+            }
             else if (e.Key == Key.PageDown)
             {
                 _viewModel.SelectNextPageCommand.Execute(null);

src/modules/launcher/PowerLauncher/ViewModel/MainViewModel.cs

@@ -151,6 +151,16 @@ namespace PowerLauncher.ViewModel
                 SelectedResults.SelectPrevTabItem();
             });
 
+            SelectNextContextMenuItemCommand = new RelayCommand(_ =>
+            {
+                SelectedResults.SelectNextContextMenuItem();
+            });
+
+            SelectPreviousContextMenuItemCommand = new RelayCommand(_ =>
+            {
+                SelectedResults.SelectPreviousContextMenuItem();
+            });
+
             SelectNextPageCommand = new RelayCommand(_ =>
             {
                 SelectedResults.SelectNextPage();
@@ -342,6 +352,8 @@ namespace PowerLauncher.ViewModel
         public ICommand EscCommand { get; set; }
         public ICommand SelectNextItemCommand { get; set; }
         public ICommand SelectPrevItemCommand { get; set; }
+        public ICommand SelectNextContextMenuItemCommand { get; set; }
+        public ICommand SelectPreviousContextMenuItemCommand { get; set; }
 
         public ICommand SelectNextTabItemCommand { get; set; }
         public ICommand SelectPrevTabItemCommand { get; set; }

src/modules/launcher/PowerLauncher/ViewModel/ResultViewModel.cs

@@ -34,7 +34,7 @@ namespace PowerLauncher.ViewModel
 
         public int ContextMenuSelectedIndex { get; set; }
 
-        const int NoSelectionIndex = -1;
+        public const int NoSelectionIndex = -1;
 
         public ResultViewModel(Result result)
         {

src/modules/launcher/PowerLauncher/ViewModel/ResultsViewModel.cs

@@ -182,6 +182,37 @@ namespace PowerLauncher.ViewModel
             }
         }
 
+        public void SelectNextContextMenuItem()
+        {
+            if(SelectedItem != null)
+            {
+                if(!SelectedItem.SelectNextContextButton())
+                {
+                    SelectedItem.SelectLastContextButton();
+                }
+            }
+        }
+
+        public void SelectPreviousContextMenuItem()
+        {
+            if (SelectedItem != null)
+            {
+                SelectedItem.SelectPrevContextButton();
+            }
+        }
+
+        public bool IsContextMenuItemSelected()
+        {
+            if (SelectedItem != null && SelectedItem.ContextMenuSelectedIndex != ResultViewModel.NoSelectionIndex)
+            {
+                return true;
+            }
+            else
+            {
+                return false;
+            }
+        }
+
         /// <summary>
         /// To avoid deadlock, this method should not called from main thread
         /// </summary>

src/modules/launcher/Wox.Core/Plugin/PluginManager.cs

@@ -17,7 +17,7 @@ namespace Wox.Core.Plugin
     /// </summary>
     public static class PluginManager
     {
-        private static IEnumerable<PluginPair> _contextMenuPlugins;
+        private static IEnumerable<PluginPair> _contextMenuPlugins = new List<PluginPair>();
 
         /// <summary>
         /// Directories that will hold Wox plugin directory

src/modules/launcher/Wox.Test/ResultsViewModelTest.cs

@@ -0,0 +1,172 @@
+using NUnit.Framework;
+using PowerLauncher.ViewModel;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Wox.Core.Plugin;
+using Wox.Plugin;
+
+namespace Wox.Test
+{
+    [TestFixture]
+    class ResultsViewModelTest
+    {
+        [Test]
+        public void ContextMenuSelectedIndex_ShouldEqualNoSelectionIndex_WhenInitialized()
+        {
+            // Arrange
+            ResultsViewModel rvm = new ResultsViewModel();
+            Result result = new Result();
+            ResultViewModel selectedItem = new ResultViewModel(result);
+            selectedItem.ContextMenuItems.Add(new ContextMenuItemViewModel()
+            {
+                Title = "Dummy Context Menu"
+            });
+            rvm.SelectedItem = selectedItem;
+
+            // Assert
+            Assert.AreEqual(selectedItem.ContextMenuSelectedIndex, ResultViewModel.NoSelectionIndex);
+        }
+
+        [Test]
+        public void SelectNextContextMenuItem_IncrementsContextMenuSelectedIndex_WhenCalled()
+        {
+            // Arrange
+            ResultsViewModel rvm = new ResultsViewModel();
+            Result result = new Result();
+            ResultViewModel selectedItem = new ResultViewModel(result);
+            selectedItem.ContextMenuItems.Add(new ContextMenuItemViewModel()
+            {
+                Title = "Dummy Context Menu"
+            });
+            rvm.SelectedItem = selectedItem;
+
+
+            // Act
+            rvm.SelectNextContextMenuItem();
+
+            // Assert
+            Assert.AreEqual(selectedItem.ContextMenuSelectedIndex, 0);
+        }
+
+        [Test]
+        public void SelectNextContextMenuItem_DoesnNotIncrementContextMenuSelectedIndex_WhenCalledOnLastItem()
+        {
+            // Arrange
+            ResultsViewModel rvm = new ResultsViewModel();
+            Result result = new Result();
+            ResultViewModel selectedItem = new ResultViewModel(result);
+            selectedItem.ContextMenuItems.Add(new ContextMenuItemViewModel()
+            {
+                Title = "Dummy Context Menu"
+            });
+            rvm.SelectedItem = selectedItem;
+
+
+            // Act
+            rvm.SelectNextContextMenuItem();
+
+            // Assert
+            Assert.AreEqual(selectedItem.ContextMenuSelectedIndex, 0);
+        }
+
+        [Test]
+        public void SelectPreviousContextMenuItem_DecrementsContextMenuSelectedIndex_WhenCalled()
+        {
+            // Arrange
+            ResultsViewModel rvm = new ResultsViewModel();
+            Result result = new Result();
+            ResultViewModel selectedItem = new ResultViewModel(result);
+            selectedItem.ContextMenuItems.Add(new ContextMenuItemViewModel()
+            {
+                Title = "Dummy Context Menu 1"
+            });
+            selectedItem.ContextMenuItems.Add(new ContextMenuItemViewModel()
+            {
+                Title = "Dummy Context Menu 2"
+            });
+            selectedItem.ContextMenuItems.Add(new ContextMenuItemViewModel()
+            {
+                Title = "Dummy Context Menu 3"
+            });
+            rvm.SelectedItem = selectedItem;
+
+
+            // Act
+            rvm.SelectNextContextMenuItem();
+            rvm.SelectNextContextMenuItem();
+            rvm.SelectNextContextMenuItem();
+            rvm.SelectPreviousContextMenuItem();
+
+            // Assert
+            Assert.AreEqual(selectedItem.ContextMenuSelectedIndex, 1);
+        }
+
+        [Test]
+        public void SelectPreviousContextMenuItem_ResetsContextMenuSelectedIndex_WhenCalledOnFirstItem()
+        {
+            // Arrange
+            ResultsViewModel rvm = new ResultsViewModel();
+            Result result = new Result();
+            ResultViewModel selectedItem = new ResultViewModel(result);
+            selectedItem.ContextMenuItems.Add(new ContextMenuItemViewModel()
+            {
+                Title = "Dummy Context Menu"
+            });
+            rvm.SelectedItem = selectedItem;
+
+
+            // Act
+            rvm.SelectNextContextMenuItem();
+            rvm.SelectPreviousContextMenuItem();
+
+            // Assert
+            Assert.AreEqual(selectedItem.ContextMenuSelectedIndex, ResultViewModel.NoSelectionIndex);
+        }
+
+        [Test]
+        public void IsContextMenuItemSelected_ReturnsTrue_WhenContextMenuItemIsSelected()
+        {
+            // Arrange
+            ResultsViewModel rvm = new ResultsViewModel();
+            Result result = new Result();
+            ResultViewModel selectedItem = new ResultViewModel(result);
+            selectedItem.ContextMenuItems.Add(new ContextMenuItemViewModel()
+            {
+                Title = "Dummy Context Menu"
+            });
+            rvm.SelectedItem = selectedItem;
+
+
+            // Act
+            rvm.SelectNextContextMenuItem();
+            bool isContextMenuItemSelected = rvm.IsContextMenuItemSelected();
+
+            // Assert
+            Assert.IsTrue(isContextMenuItemSelected);
+        }
+
+        [Test]
+        public void IsContextMenuItemSelected_ReturnsFalse_WhenContextMenuItemIsNotSelected()
+        {
+            // Arrange
+            ResultsViewModel rvm = new ResultsViewModel();
+            Result result = new Result();
+            ResultViewModel selectedItem = new ResultViewModel(result);
+            selectedItem.ContextMenuItems.Add(new ContextMenuItemViewModel()
+            {
+                Title = "Dummy Context Menu"
+            });
+            rvm.SelectedItem = selectedItem;
+
+
+            // Act
+            rvm.SelectNextContextMenuItem();
+            rvm.SelectPreviousContextMenuItem();
+            bool isContextMenuItemSelected = rvm.IsContextMenuItemSelected();
+
+            // Assert
+            Assert.IsFalse(isContextMenuItemSelected);
+        }
+    }
+}