add: table of contents

2024-07-29 21:52:23 +08:00
parent 12777c227d
commit 91ae6d8ac1
7 changed files with 219 additions and 4 deletions
--- a/YaeBlog.Core/Processors/HeadlinePostRenderProcessor.cs
+++ b/YaeBlog.Core/Processors/HeadlinePostRenderProcessor.cs
@@ -0,0 +1,105 @@
+using AngleSharp;
+using AngleSharp.Dom;
+using YaeBlog.Core.Abstractions;
+using YaeBlog.Core.Models;
+using YaeBlog.Core.Services;
+
+namespace YaeBlog.Core.Processors;
+
+public class HeadlinePostRenderProcessor(
+    IConfiguration angleConfiguration,
+    TableOfContentService tableOfContentService) : IPostRenderProcessor
+{
+    public async Task<BlogEssay> ProcessAsync(BlogEssay essay)
+    {
+        BrowsingContext browsingContext = new(angleConfiguration);
+        IDocument document = await browsingContext.OpenAsync(req => req.Content(essay.HtmlContent));
+
+        IEnumerable<IElement> elements = from item in document.All
+            where item.LocalName is "h2" or "h3" or "h4"
+            select item;
+
+        BlogHeadline topHeadline = new(essay.Title, "#title");
+        List<BlogHeadline> level2List = [];
+        List<BlogHeadline> level3List = [];
+        List<BlogHeadline> level4List = [];
+
+        foreach (IElement element in elements)
+        {
+            switch (element.LocalName)
+            {
+                case "h2":
+                    {
+                        FindParentHeadline(topHeadline, level2List, level3List).Children.AddRange(level4List);
+                        level4List.Clear();
+                        FindParentHeadline(topHeadline, level2List).Children.AddRange(level3List);
+                        level3List.Clear();
+
+                        BlogHeadline headline = ParserHeadlineElement(element);
+                        level2List.Add(headline);
+                        break;
+                    }
+                case "h3":
+                    {
+                        FindParentHeadline(topHeadline, level2List, level3List).Children.AddRange(level4List);
+                        level4List.Clear();
+
+                        BlogHeadline headline = ParserHeadlineElement(element);
+                        level3List.Add(headline);
+                        break;
+                    }
+                case "h4":
+                    {
+                        BlogHeadline headline = ParserHeadlineElement(element);
+                        level4List.Add(headline);
+                        break;
+                    }
+            }
+        }
+
+        // 太抽象了（（（
+        FindParentHeadline(topHeadline, level2List, level3List).Children.AddRange(level4List);
+        FindParentHeadline(topHeadline, level2List).Children.AddRange(level3List);
+        topHeadline.Children.AddRange(level2List);
+
+        tableOfContentService.AddHeadline(essay.FileName, topHeadline);
+
+        return essay.WithNewHtmlContent(document.DocumentElement.OuterHtml);
+    }
+
+    private static BlogHeadline ParserHeadlineElement(IElement element)
+    {
+        element.Id ??= element.TextContent;
+        return new BlogHeadline(element.TextContent, element.Id);
+    }
+
+    /// <summary>
+    /// 找到h4标题的父级标题
+    /// </summary>
+    /// <param name="topHeadline"></param>
+    /// <param name="level2"></param>
+    /// <param name="level3"></param>
+    /// <returns></returns>
+    private static BlogHeadline FindParentHeadline(BlogHeadline topHeadline, List<BlogHeadline> level2,
+        List<BlogHeadline> level3)
+    {
+        BlogHeadline? result = level3.LastOrDefault();
+        if (result is not null)
+        {
+            return result;
+        }
+
+        return level2.LastOrDefault() ?? topHeadline;
+    }
+
+    /// <summary>
+    /// 找到h3标题的父级标题
+    /// </summary>
+    /// <param name="topHeadline"></param>
+    /// <param name="level2"></param>
+    /// <returns></returns>
+    private static BlogHeadline FindParentHeadline(BlogHeadline topHeadline, List<BlogHeadline> level2) =>
+        FindParentHeadline(topHeadline, level2, []);
+
+    public string Name => nameof(HeadlinePostRenderProcessor);
+}