refactor<*>: rewrite all with AvaloniaUI

src/ViewModels/TwoSideTextDiff.cs

@@ -0,0 +1,52 @@
+using Avalonia;
+using CommunityToolkit.Mvvm.ComponentModel;
+using System.Collections.Generic;
+
+namespace SourceGit.ViewModels {
+    public class TwoSideTextDiff : ObservableObject {
+        public Vector SyncScrollOffset {
+            get => _syncScrollOffset;
+            set => SetProperty(ref _syncScrollOffset, value);
+        }
+
+        public string File { get; set; } = string.Empty;
+        public List<Models.TextDiffLine> Old { get; set; } = new List<Models.TextDiffLine>();
+        public List<Models.TextDiffLine> New { get; set; } = new List<Models.TextDiffLine>();
+        public int MaxLineNumber = 0;
+
+        public TwoSideTextDiff(Models.TextDiff diff) {
+            File = diff.File;
+            MaxLineNumber = diff.MaxLineNumber;
+
+            foreach (var line in diff.Lines) {
+                switch (line.Type) {
+                case Models.TextDiffLineType.Added:
+                    New.Add(line);
+                    break;
+                case Models.TextDiffLineType.Deleted:
+                    Old.Add(line);
+                    break;
+                default:
+                    FillEmptyLines();
+                    Old.Add(line);
+                    New.Add(line);
+                    break;
+                }
+            }
+
+            FillEmptyLines();
+        }
+
+        private void FillEmptyLines() {
+            if (Old.Count < New.Count) {
+                int diff = New.Count - Old.Count;
+                for (int i = 0; i < diff; i++) Old.Add(new Models.TextDiffLine());
+            } else if (Old.Count > New.Count) {
+                int diff = Old.Count - New.Count;
+                for (int i = 0; i < diff; i++) New.Add(new Models.TextDiffLine());
+            }
+        }
+
+        private Vector _syncScrollOffset;
+    }
+}