enhance: keep scroll after staging/unstaging/discarding hunks (#2072) (#2083)

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

Author: love-linger

src/ViewModels/BlockNavigation.cs

@@ -110,6 +110,29 @@ public Block Goto(BlockNavigationDirection direction)
             return _blocks[_current];
         }
 
+        public void UpdateByChunk(TextDiffSelectedChunk chunk)
+        {
+            _current = -1;
+
+            var chunkStart = chunk.StartIdx + 1;
+            var chunkEnd = chunk.EndIdx + 1;
+
+            for (var i = 0; i < _blocks.Count; i++)
+            {
+                var block = _blocks[i];
+                if (chunkStart > block.End)
+                    continue;
+
+                if (chunkEnd < block.Start)
+                {
+                    _current = i - 1;
+                    break;
+                }
+
+                _current = i;
+            }
+        }
+
         public void UpdateByCaretPosition(int caretLine)
         {
             if (_current >= 0 && _current < _blocks.Count)

src/Views/TextDiffView.axaml.cs

@@ -1464,7 +1464,7 @@ protected override void OnPointerExited(PointerEventArgs e)
 
         private async void OnStageChunk(object _1, RoutedEventArgs _2)
         {
-            if (DataContext is not ViewModels.TextDiffContext { SelectedChunk: { } chunk, Data: { } diff, Option: { IsUnstaged: true, WorkingCopyChange: { } change } })
+            if (DataContext is not ViewModels.TextDiffContext { SelectedChunk: { } chunk, Data: { } diff, Option: { IsUnstaged: true, WorkingCopyChange: { } change } } vm)
                 return;
 
             var selection = diff.MakeSelection(chunk.StartIdx + 1, chunk.EndIdx + 1, chunk.Combined, chunk.IsOldSide);
@@ -1496,12 +1496,13 @@ private async void OnStageChunk(object _1, RoutedEventArgs _2)
             await new Commands.Apply(repo.FullPath, tmpFile, true, "nowarn", "--cache --index").ExecAsync();
             File.Delete(tmpFile);
 
+            vm.BlockNavigation.UpdateByChunk(chunk);
             repo.MarkWorkingCopyDirtyManually();
         }
 
         private async void OnUnstageChunk(object _1, RoutedEventArgs _2)
         {
-            if (DataContext is not ViewModels.TextDiffContext { SelectedChunk: { } chunk, Data: { } diff, Option: { IsUnstaged: false, WorkingCopyChange: { } change } })
+            if (DataContext is not ViewModels.TextDiffContext { SelectedChunk: { } chunk, Data: { } diff, Option: { IsUnstaged: false, WorkingCopyChange: { } change } } vm)
                 return;
 
             var selection = diff.MakeSelection(chunk.StartIdx + 1, chunk.EndIdx + 1, chunk.Combined, chunk.IsOldSide);
@@ -1526,12 +1527,13 @@ private async void OnUnstageChunk(object _1, RoutedEventArgs _2)
             await new Commands.Apply(repo.FullPath, tmpFile, true, "nowarn", "--cache --index --reverse").ExecAsync();
             File.Delete(tmpFile);
 
+            vm.BlockNavigation.UpdateByChunk(chunk);
             repo.MarkWorkingCopyDirtyManually();
         }
 
         private async void OnDiscardChunk(object _1, RoutedEventArgs _2)
         {
-            if (DataContext is not ViewModels.TextDiffContext { SelectedChunk: { } chunk, Data: { } diff, Option: { IsUnstaged: true, WorkingCopyChange: { } change } })
+            if (DataContext is not ViewModels.TextDiffContext { SelectedChunk: { } chunk, Data: { } diff, Option: { IsUnstaged: true, WorkingCopyChange: { } change } } vm)
                 return;
 
             var selection = diff.MakeSelection(chunk.StartIdx + 1, chunk.EndIdx + 1, chunk.Combined, chunk.IsOldSide);
@@ -1563,6 +1565,7 @@ private async void OnDiscardChunk(object _1, RoutedEventArgs _2)
             await new Commands.Apply(repo.FullPath, tmpFile, true, "nowarn", "--reverse").ExecAsync();
             File.Delete(tmpFile);
 
+            vm.BlockNavigation.UpdateByChunk(chunk);
             repo.MarkWorkingCopyDirtyManually();
         }
     }