feat: Versioning of blog posts

Directory.Packages.props

@@ -3,6 +3,7 @@
     <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
   </PropertyGroup>
   <ItemGroup Label="Code Analyzers">
+    <PackageVersion Include="DiffPlex" Version="1.9.0" />
     <PackageVersion Include="IDisposableAnalyzers" Version="4.0.8" />
     <GlobalPackageReference Include="SonarAnalyzer.CSharp" Version="10.23.0.137933" PrivateAssets="All" IncludeAssets="Runtime;Build;Native;contentFiles;Analyzers" />
   </ItemGroup>
@@ -60,4 +61,4 @@
   <ItemGroup Label="Source Code Generators">
     <PackageVersion Include="LinkDotNet.Enumeration" Version="1.4.0" />
   </ItemGroup>
-</Project>
+</Project>

src/LinkDotNet.Blog.Domain/BlogPostVersion.cs

@@ -0,0 +1,59 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Linq;
+
+namespace LinkDotNet.Blog.Domain;
+
+public sealed class BlogPostVersion : Entity
+{
+    public string BlogPostId { get; private set; } = default!;
+
+    public int VersionNumber { get; private set; }
+
+    public DateTime CreatedAt { get; private set; }
+
+    public string Title { get; private set; } = default!;
+
+    public string ShortDescription { get; private set; } = default!;
+
+    public string Content { get; private set; } = default!;
+
+    public string PreviewImageUrl { get; private set; } = default!;
+
+    public string? PreviewImageUrlFallback { get; private set; }
+
+    public DateTime UpdatedDate { get; private set; }
+
+    public IList<string> Tags { get; private set; } = [];
+
+    public bool IsPublished { get; private set; }
+
+    public int ReadingTimeInMinutes { get; private set; }
+
+    public string? AuthorName { get; private set; }
+
+    public string TagsAsString => string.Join(",", Tags);
+
+    public static BlogPostVersion CreateSnapshot(BlogPost post, int versionNumber)
+    {
+        ArgumentNullException.ThrowIfNull(post);
+
+        return new BlogPostVersion
+        {
+            BlogPostId = post.Id,
+            VersionNumber = versionNumber,
+            CreatedAt = DateTime.UtcNow,
+            Title = post.Title,
+            ShortDescription = post.ShortDescription,
+            Content = post.Content,
+            PreviewImageUrl = post.PreviewImageUrl,
+            PreviewImageUrlFallback = post.PreviewImageUrlFallback,
+            UpdatedDate = post.UpdatedDate,
+            Tags = post.Tags.ToImmutableArray(),
+            IsPublished = post.IsPublished,
+            ReadingTimeInMinutes = post.ReadingTimeInMinutes,
+            AuthorName = post.AuthorName,
+        };
+    }
+}