enhance: introduce template engine for commit templates (#704) (#719)

Author: aikawayataro

src/Models/CommitTemplate.cs

@@ -1,17 +1,11 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
-using System.Text.RegularExpressions;
+using System.Collections.Generic;
 
 using CommunityToolkit.Mvvm.ComponentModel;
 
 namespace SourceGit.Models
 {
     public partial class CommitTemplate : ObservableObject
     {
-        [GeneratedRegex(@"\$\{files(\:\d+)?\}")]
-        private static partial Regex REG_COMMIT_TEMPLATE_FILES();
-
         public string Name
         {
             get => _name;
@@ -26,55 +20,8 @@ public string Content
 
         public string Apply(Branch branch, List<Change> changes)
         {
-            var content = _content
-                .Replace("${files_num}", $"{changes.Count}")
-                .Replace("${branch_name}", branch.Name);
-
-            var matches = REG_COMMIT_TEMPLATE_FILES().Matches(content);
-            if (matches.Count == 0)
-                return content;
-
-            var builder = new StringBuilder();
-            var last = 0;
-            for (int i = 0; i < matches.Count; i++)
-            {
-                var match = matches[i];
-                if (!match.Success)
-                    continue;
-
-                var start = match.Index;
-                if (start != last)
-                    builder.Append(content.Substring(last, start - last));
-
-                var countStr = match.Groups[1].Value;
-                var paths = new List<string>();
-                var more = string.Empty;
-                if (countStr is { Length: <= 1 })
-                {
-                    foreach (var c in changes)
-                        paths.Add(c.Path);
-                }
-                else
-                {
-                    var count = Math.Min(int.Parse(countStr.Substring(1)), changes.Count);
-                    for (int j = 0; j < count; j++)
-                        paths.Add(changes[j].Path);
-
-                    if (count < changes.Count)
-                        more = $" and {changes.Count - count} other files";
-                }
-
-                builder.Append(string.Join(", ", paths));
-                if (!string.IsNullOrEmpty(more))
-                    builder.Append(more);
-
-                last = start + match.Length;
-            }
-
-            if (last != content.Length - 1)
-                builder.Append(content.Substring(last));
-
-            return builder.ToString();
+            var te = new TemplateEngine();
+            return te.Eval(_content, branch, changes);
         }
 
         private string _name = string.Empty;