From 134c71064ece232d9253c45bde10c8fc7daa7494 Mon Sep 17 00:00:00 2001
From: leo <longshuang@msn.cn>
Date: Sat, 16 Nov 2024 14:54:50 +0800
Subject: [PATCH] feature: add buttons to go to prev/next change in text diff
 view (#616)

Signed-off-by: leo <longshuang@msn.cn>
---
 src/Views/DiffView.axaml        |  41 +++++++-----
 src/Views/DiffView.axaml.cs     |  28 +++++++++
 src/Views/TextDiffView.axaml.cs | 108 ++++++++++++++++++++++++++++++++
 3 files changed, 161 insertions(+), 16 deletions(-)

diff --git a/src/Views/DiffView.axaml b/src/Views/DiffView.axaml
index 06525abd..e0627ad8 100644
--- a/src/Views/DiffView.axaml
+++ b/src/Views/DiffView.axaml
@@ -34,8 +34,24 @@
 
           <!-- Toolbar Buttons -->
           <StackPanel Grid.Column="3" Margin="8,0,0,0" Orientation="Horizontal" VerticalAlignment="Center">
+            <Button Classes="icon_button"
+                    Width="28"
+                    Click="OnGotoPrevChange"
+                    IsVisible="{Binding IsTextDiff}"
+                    ToolTip.Tip="{DynamicResource Text.Diff.Prev}">
+              <Path Width="12" Height="12" Stretch="Uniform" Margin="0,6,0,0" Data="{StaticResource Icons.Up}"/>
+            </Button>
+
+            <Button Classes="icon_button"
+                    Width="28"
+                    Click="OnGotoNextChange"
+                    IsVisible="{Binding IsTextDiff}"
+                    ToolTip.Tip="{DynamicResource Text.Diff.Next}">
+              <Path Width="12" Height="12" Stretch="Uniform" Margin="0,6,0,0" Data="{StaticResource Icons.Down}"/>
+            </Button>
+            
             <Button Classes="icon_button" 
-                    Width="32" 
+                    Width="28"
                     Command="{Binding IncrUnified}" 
                     IsVisible="{Binding IsTextDiff}"
                     ToolTip.Tip="{DynamicResource Text.Diff.VisualLines.Incr}">
@@ -46,7 +62,7 @@
             </Button>
 
             <Button Classes="icon_button" 
-                    Width="32" 
+                    Width="28" 
                     Command="{Binding DecrUnified}" 
                     IsVisible="{Binding IsTextDiff}" 
                     ToolTip.Tip="{DynamicResource Text.Diff.VisualLines.Decr}">
@@ -60,9 +76,7 @@
             </Button>
             
             <ToggleButton Classes="line_path"
-                          Width="32" Height="18"
-                          Background="Transparent"
-                          Padding="9,6"
+                          Width="28"
                           Command="{Binding ToggleFullTextDiff}"
                           IsChecked="{Binding Source={x:Static vm:Preference.Instance}, Path=UseFullTextDiff, Mode=OneWay}"
                           IsVisible="{Binding IsTextDiff}"
@@ -71,9 +85,8 @@
             </ToggleButton>
 
             <ToggleButton Classes="line_path"
-                          Width="32" Height="18"
+                          Width="28"
                           Background="Transparent"
-                          Padding="9,6"
                           IsChecked="{Binding Source={x:Static vm:Preference.Instance}, Path=UseSyntaxHighlighting, Mode=TwoWay}"
                           IsVisible="{Binding IsTextDiff}"
                           ToolTip.Tip="{DynamicResource Text.Diff.SyntaxHighlight}">
@@ -81,9 +94,7 @@
             </ToggleButton>
 
             <ToggleButton Classes="line_path"
-                          Width="32" Height="18"
-                          Background="Transparent"
-                          Padding="9,6"
+                          Width="28"
                           IsChecked="{Binding Source={x:Static vm:Preference.Instance}, Path=EnableDiffViewWordWrap, Mode=TwoWay}"
                           ToolTip.Tip="{DynamicResource Text.Diff.ToggleWordWrap}">
               <ToggleButton.IsVisible>
@@ -97,14 +108,14 @@
             </ToggleButton>
 
             <ToggleButton Classes="line_path"
-                          Width="32"
+                          Width="28"
                           IsChecked="{Binding IgnoreWhitespace, Mode=TwoWay}"
                           ToolTip.Tip="{DynamicResource Text.Diff.IgnoreWhitespace}">
               <Path Width="14" Height="14" Stretch="Uniform" Data="{StaticResource Icons.Whitespace}"/>
             </ToggleButton>
 
             <ToggleButton Classes="line_path"
-                          Width="32"
+                          Width="28"
                           IsChecked="{Binding Source={x:Static vm:Preference.Instance}, Path=ShowHiddenSymbolsInDiffView, Mode=TwoWay}"
                           IsVisible="{Binding IsTextDiff}"
                           ToolTip.Tip="{DynamicResource Text.Diff.ShowHiddenSymbols}">
@@ -112,16 +123,14 @@
             </ToggleButton>
 
             <ToggleButton Classes="line_path"
-                          Width="32" Height="18"
-                          Background="Transparent"
-                          Padding="9,6"
+                          Width="28" Height="18"
                           IsChecked="{Binding Source={x:Static vm:Preference.Instance}, Path=UseSideBySideDiff, Mode=TwoWay}"
                           IsVisible="{Binding IsTextDiff}"
                           ToolTip.Tip="{DynamicResource Text.Diff.SideBySide}">
               <Path Width="12" Height="12" Data="{StaticResource Icons.LayoutHorizontal}" Margin="0,2,0,0"/>
             </ToggleButton>
 
-            <Button Classes="icon_button" Width="32" Command="{Binding OpenExternalMergeTool}" ToolTip.Tip="{DynamicResource Text.Diff.UseMerger}">
+            <Button Classes="icon_button" Width="28" Command="{Binding OpenExternalMergeTool}" ToolTip.Tip="{DynamicResource Text.Diff.UseMerger}">
               <Path Width="12" Height="12" Stretch="Uniform" Data="{StaticResource Icons.OpenWith}"/>
             </Button>
           </StackPanel>
diff --git a/src/Views/DiffView.axaml.cs b/src/Views/DiffView.axaml.cs
index 860627d3..7184ec44 100644
--- a/src/Views/DiffView.axaml.cs
+++ b/src/Views/DiffView.axaml.cs
@@ -1,4 +1,6 @@
 using Avalonia.Controls;
+using Avalonia.Interactivity;
+using Avalonia.VisualTree;
 
 namespace SourceGit.Views
 {
@@ -8,5 +10,31 @@ namespace SourceGit.Views
         {
             InitializeComponent();
         }
+
+        private void OnGotoPrevChange(object _, RoutedEventArgs e)
+        {
+            var textDiff = this.FindDescendantOfType<ThemedTextDiffPresenter>();
+            if (textDiff == null)
+                return;
+
+            textDiff.GotoPrevChange();
+            if (textDiff is SingleSideTextDiffPresenter presenter)
+                presenter.ForceSyncScrollOffset();
+
+            e.Handled = true;
+        }
+
+        private void OnGotoNextChange(object _, RoutedEventArgs e)
+        {
+            var textDiff = this.FindDescendantOfType<ThemedTextDiffPresenter>();
+            if (textDiff == null)
+                return;
+
+            textDiff.GotoNextChange();
+            if (textDiff is SingleSideTextDiffPresenter presenter)
+                presenter.ForceSyncScrollOffset();
+
+            e.Handled = true;
+        }
     }
 }
diff --git a/src/Views/TextDiffView.axaml.cs b/src/Views/TextDiffView.axaml.cs
index 913a6340..fb2693a8 100644
--- a/src/Views/TextDiffView.axaml.cs
+++ b/src/Views/TextDiffView.axaml.cs
@@ -498,6 +498,108 @@ namespace SourceGit.Views
         {
         }
 
+        public void GotoPrevChange()
+        {
+            var view = TextArea.TextView;
+            var lines = GetLines();
+            var firstLineIdx = lines.Count;
+            foreach (var line in view.VisualLines)
+            {
+                if (line.IsDisposed || line.FirstDocumentLine == null || line.FirstDocumentLine.IsDeleted)
+                    continue;
+
+                var index = line.FirstDocumentLine.LineNumber - 1;
+                if (index >= lines.Count)
+                    continue;
+
+                if (firstLineIdx > index)
+                    firstLineIdx = index;
+            }
+
+            var firstLineType = lines[firstLineIdx].Type;
+            var isChangeFirstLine = firstLineType != Models.TextDiffLineType.Normal && firstLineType != Models.TextDiffLineType.Indicator;
+            if (isChangeFirstLine)
+            {
+                for (var i = firstLineIdx - 1; i >= 0; i--)
+                {
+                    var prevType = lines[i].Type;
+                    if (prevType == Models.TextDiffLineType.Normal || prevType == Models.TextDiffLineType.Indicator)
+                    {
+                        ScrollToLine(i + 2);
+                        return;
+                    }
+                }
+            }
+            else
+            {
+                var prevChangeEnd = -1;
+                for (var i = firstLineIdx - 1; i >= 0; i--)
+                {
+                    var prevType = lines[i].Type;
+                    if (prevType == Models.TextDiffLineType.None ||
+                        prevType == Models.TextDiffLineType.Added ||
+                        prevType == Models.TextDiffLineType.Deleted)
+                    {
+                        prevChangeEnd = i;
+                        break;
+                    }
+                }
+
+                if (prevChangeEnd <= 0)
+                    return;
+
+                for (var i = prevChangeEnd - 1; i >= 0; i--)
+                {
+                    var prevType = lines[i].Type;
+                    if (prevType == Models.TextDiffLineType.Normal || prevType == Models.TextDiffLineType.Indicator)
+                    {
+                        ScrollToLine(i + 2);
+                        return;
+                    }
+                }
+            }
+        }
+
+        public void GotoNextChange()
+        {
+            var view = TextArea.TextView;
+            var lines = GetLines();
+            var lastLineIdx = -1;
+            foreach (var line in view.VisualLines)
+            {
+                if (line.IsDisposed || line.FirstDocumentLine == null || line.FirstDocumentLine.IsDeleted)
+                    continue;
+
+                var index = line.FirstDocumentLine.LineNumber - 1;
+                if (index >= lines.Count)
+                    continue;
+
+                if (lastLineIdx < index)
+                    lastLineIdx = index;
+            }
+
+            var lastLineType = lines[lastLineIdx].Type;
+            var findNormalLine = lastLineType == Models.TextDiffLineType.Normal || lastLineType == Models.TextDiffLineType.Indicator;
+            for (var idx = lastLineIdx + 1; idx < lines.Count; idx++)
+            {
+                var nextType = lines[idx].Type;
+                if (nextType == Models.TextDiffLineType.None ||
+                    nextType == Models.TextDiffLineType.Added ||
+                    nextType == Models.TextDiffLineType.Deleted)
+                {
+                    if (findNormalLine)
+                    {
+                        ScrollToLine(idx + 1);
+                        return;
+                    }
+                }
+                else if (!findNormalLine)
+                {
+                    findNormalLine = true;
+                }
+            }
+        }
+
         public override void Render(DrawingContext context)
         {
             base.Render(context);
@@ -968,6 +1070,12 @@ namespace SourceGit.Views
             TextArea.LeftMargins.Add(new LineModifyTypeMargin());
         }
 
+        public void ForceSyncScrollOffset()
+        {
+            if (DataContext is ViewModels.TwoSideTextDiff diff)
+                diff.SyncScrollOffset = _scrollViewer.Offset;
+        }
+
         public override List<Models.TextDiffLine> GetLines()
         {
             if (DataContext is ViewModels.TwoSideTextDiff diff)