C#实现生成Markdown文档目录树

ExtractToc.cs

class Heading {
    public int Id { get; set; }
    public int Pid { get; set; } = -1;
    public string? Text { get; set; }
    public string? Slug { get; set; }
    public int Level { get; set; }
}

public class TocNode {
    public string? Text { get; set; }
    public string? Href { get; set; }
    public List<string>? Tags { get; set; }
    public List<TocNode>? Nodes { get; set; }
}

public static List<TocNode>? ExtractToc(this MarkdownDocument document) {
    var headings = new List<Heading>();

    foreach (var heading in document.Descendants<HeadingBlock>()) {
        var item = new Heading {Level = heading.Level, Text = heading.Inline?.FirstChild?.ToString()};
        headings.Add(item);
    }

    var chineseTitleCount = 0;
    for (var i = 0; i < headings.Count; i++) {
        var item = headings[i];
        item.Id = i;

        var text = item.Text ?? "";
        if (Regex.IsMatch(text, "[\u4e00-\u9fbb]")) {
            item.Slug = chineseTitleCount == 0 ? "section" : $"section-{chineseTitleCount}";
            chineseTitleCount++;
        }
        else {
            item.Slug = text.Replace(" ", "-").ToLower();
        }

        for (var j = i; j >= 0; j--) {
            var preItem = headings[j];
            if (item.Level == preItem.Level + 1) {
                item.Pid = j;
                break;
            }
        }
    }

    List<TocNode>? GetNodes(int pid = -1) {
        var nodes = headings.Where(a => a.Pid == pid).ToList();
        return nodes.Count == 0
            ? null
            : nodes.Select(a => new TocNode {Text = a.Text, Href = $"#{a.Slug}", Nodes = GetNodes(a.Id)}).ToList();
    }

    return GetNodes();
}