feature: support to copy selected line(s) as patch in text diff viewer

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

Author: love-linger

src/Resources/Locales/en_US.axaml

@@ -306,6 +306,7 @@
   <x:String x:Key="Text.ConventionalCommit.Type" xml:space="preserve">Type of Change:</x:String>
   <x:String x:Key="Text.Copy" xml:space="preserve">Copy</x:String>
   <x:String x:Key="Text.CopyAllText" xml:space="preserve">Copy All Text</x:String>
+  <x:String x:Key="Text.CopyAsPatch" xml:space="preserve">Copy as Patch</x:String>
   <x:String x:Key="Text.CopyFullPath" xml:space="preserve">Copy Full Path</x:String>
   <x:String x:Key="Text.CopyPath" xml:space="preserve">Copy Path</x:String>
   <x:String x:Key="Text.CreateBranch" xml:space="preserve">Create Branch...</x:String>

src/Resources/Locales/zh_CN.axaml

@@ -310,6 +310,7 @@
   <x:String x:Key="Text.ConventionalCommit.Type" xml:space="preserve">类型：</x:String>
   <x:String x:Key="Text.Copy" xml:space="preserve">复制</x:String>
   <x:String x:Key="Text.CopyAllText" xml:space="preserve">复制全部文本</x:String>
+  <x:String x:Key="Text.CopyAsPatch" xml:space="preserve">复制为补丁</x:String>
   <x:String x:Key="Text.CopyFullPath" xml:space="preserve">复制完整路径</x:String>
   <x:String x:Key="Text.CopyPath" xml:space="preserve">复制路径</x:String>
   <x:String x:Key="Text.CreateBranch" xml:space="preserve">新建分支 ...</x:String>

src/Resources/Locales/zh_TW.axaml

@@ -310,6 +310,7 @@
   <x:String x:Key="Text.ConventionalCommit.Type" xml:space="preserve">類型:</x:String>
   <x:String x:Key="Text.Copy" xml:space="preserve">複製</x:String>
   <x:String x:Key="Text.CopyAllText" xml:space="preserve">複製全部內容</x:String>
+  <x:String x:Key="Text.CopyAsPatch" xml:space="preserve">複製為修補檔</x:String>
   <x:String x:Key="Text.CopyFullPath" xml:space="preserve">複製完整路徑</x:String>
   <x:String x:Key="Text.CopyPath" xml:space="preserve">複製路徑</x:String>
   <x:String x:Key="Text.CreateBranch" xml:space="preserve">新增分支...</x:String>

src/Views/TextDiffView.axaml.cs

@@ -649,8 +649,18 @@ private void OnTextViewContextRequested(object sender, ContextRequestedEventArgs
                 ev.Handled = true;
             };
 
+            var copyAsPatch = new MenuItem();
+            copyAsPatch.Header = App.Text("CopyAsPatch");
+            copyAsPatch.Icon = this.CreateMenuIcon("Icons.Copy");
+            copyAsPatch.Click += async (_, ev) =>
+            {
+                await CopyAsPatchAsync();
+                ev.Handled = true;
+            };
+
             var menu = new ContextMenu();
             menu.Items.Add(copy);
+            menu.Items.Add(copyAsPatch);
             menu.Open(TextArea.TextView);
 
             e.Handled = true;
@@ -896,6 +906,42 @@ private async Task CopyWithoutIndicatorsAsync()
             await this.CopyTextAsync(builder.ToString());
         }
 
+        private async Task CopyAsPatchAsync()
+        {
+            if (DataContext is not ViewModels.TextDiffContext { Data: { } diff, Option: { } option } ctx)
+                return;
+
+            var selection = TextArea.Selection;
+            var startPosition = selection.StartPosition;
+            var endPosition = selection.EndPosition;
+
+            if (startPosition.Location > endPosition.Location)
+                (startPosition, endPosition) = (endPosition, startPosition);
+
+            var maxIdx = GetLines().Count - 1;
+            var startIdx = Math.Min(startPosition.Line - 1, maxIdx);
+            var endIdx = Math.Min(endPosition.Line - 1, maxIdx);
+            var isCombined = true;
+            if (ctx is ViewModels.TwoSideTextDiff twoSides)
+            {
+                isCombined = false;
+                twoSides.GetCombinedRangeForSingleSide(ref startIdx, ref endIdx, IsOld);
+            }
+
+            var tmpFile = Path.GetTempFileName();
+            var patch = new Models.PatchGenerator(tmpFile, option, diff);
+            var succ = patch.Generate(startIdx, endIdx, isCombined, IsOld, false);
+            if (!succ)
+            {
+                Models.Notification.Send(null, "You should select at lease one changed line!", true);
+                return;
+            }
+
+            var patchText = File.ReadAllText(tmpFile);
+            File.Delete(tmpFile);
+            await this.CopyTextAsync(patchText);
+        }
+
         private bool _execSizeChanged;
         private TextMate.Installation _textMate;
         private TextLocation _lastSelectStart = TextLocation.Empty;