refactor: use a single property to indicate drop direction

Signed-off-by: leo <longshuang@msn.cn>

Author: love-linger

src/ViewModels/InteractiveRebase.cs

@@ -4,7 +4,7 @@
 using System.Text;
 using System.Text.Json;
 using System.Threading.Tasks;
-
+using Avalonia;
 using Avalonia.Collections;
 using Avalonia.Threading;
 
@@ -82,16 +82,10 @@ public bool IsFullMessageUsed
             set => SetProperty(ref _isFullMessageUsed, value);
         }
 
-        public bool IsDropBeforeVisible
-        {
-            get => _isDropBeforeVisible;
-            set => SetProperty(ref _isDropBeforeVisible, value);
-        }
-
-        public bool IsDropAfterVisible
+        public Thickness DropDirectionIndicator
         {
-            get => _isDropAfterVisible;
-            set => SetProperty(ref _isDropAfterVisible, value);
+            get => _dropDirectionIndicator;
+            set => SetProperty(ref _dropDirectionIndicator, value);
         }
 
         public bool IsMessageUserEdited
@@ -116,8 +110,7 @@ public InteractiveRebaseItem(int order, Models.Commit c, string message, bool ca
         private bool _canSquashOrFixup = true;
         private bool _showEditMessageButton = false;
         private bool _isFullMessageUsed = true;
-        private bool _isDropBeforeVisible = false;
-        private bool _isDropAfterVisible = false;
+        private Thickness _dropDirectionIndicator = new Thickness(0);
     }
 
     public class InteractiveRebase : ObservableObject

src/Views/InteractiveRebase.axaml

@@ -118,6 +118,12 @@
                   <ColumnDefinition Width="Auto" SharedSizeGroup="CommitTimeColumn"/>
                 </Grid.ColumnDefinitions>
 
+                <!-- Drop Direction Indicator -->
+                <Border Grid.Column="0" Grid.ColumnSpan="8"
+                        Background="Transparent"
+                        BorderThickness="{Binding DropDirectionIndicator, Mode=OneWay}"
+                        BorderBrush="{DynamicResource Brush.Accent}"/>
+
                 <!-- Original Order -->
                 <TextBlock Grid.Column="0"
                            Margin="4,0,0,0"
@@ -189,20 +195,6 @@
                              Text="{Binding Commit.CommitterTimeStr}"
                              Opacity="{Binding IsFullMessageUsed, Converter={x:Static c:BoolConverters.IsMergedToOpacity}}"/>
                 </Border>
-
-                <!-- Drop Indicator -->
-                <Rectangle Grid.Column="0" Grid.ColumnSpan="8"
-                           Height="2"
-                           VerticalAlignment="Top"
-                           Fill="{DynamicResource Brush.Accent}"
-                           IsVisible="{Binding IsDropBeforeVisible, Mode=OneWay}"
-                           IsHitTestVisible="False"/>
-                <Rectangle Grid.Column="0" Grid.ColumnSpan="8"
-                           Height="2"
-                           VerticalAlignment="Bottom"
-                           Fill="{DynamicResource Brush.Accent}"
-                           IsVisible="{Binding IsDropAfterVisible, Mode=OneWay}"
-                           IsHitTestVisible="False"/>
               </Grid>
             </DataTemplate>
           </v:InteractiveRebaseListBox.ItemTemplate>

src/Views/InteractiveRebase.axaml.cs

@@ -266,9 +266,7 @@ private void OnRowDragOver(object sender, DragEventArgs e)
 
             var p = e.GetPosition(control);
             var before = p.Y < control.Bounds.Height * 0.5;
-
-            dst.IsDropBeforeVisible = before;
-            dst.IsDropAfterVisible = !before;
+            dst.DropDirectionIndicator = before ? new Thickness(0, 2, 0, 0) : new Thickness(0, 0, 0, 2);
             e.DragEffects = DragDropEffects.Move;
             e.Handled = true;
         }
@@ -278,8 +276,7 @@ private void OnRowDragLeave(object sender, DragEventArgs e)
             if (sender is not Control { DataContext: ViewModels.InteractiveRebaseItem dst })
                 return;
 
-            dst.IsDropBeforeVisible = false;
-            dst.IsDropAfterVisible = false;
+            dst.DropDirectionIndicator = new Thickness(0);
             e.Handled = true;
         }
 
@@ -315,8 +312,7 @@ private void OnRowDrop(object sender, DragEventArgs e)
             vm.Move(commits, before ? idx : idx + 1);
             IRItemListBox.SelectedItems = commits;
 
-            dst.IsDropBeforeVisible = false;
-            dst.IsDropAfterVisible = false;
+            dst.DropDirectionIndicator = new Thickness(0);
             e.DragEffects = DragDropEffects.None;
             e.Handled = true;
         }