blog/markdown/markdown.go

package markdown

import (
	"bytes"
	"fmt"
	"io"

	chromahtml "github.com/alecthomas/chroma/formatters/html"
	"github.com/yuin/goldmark"
	emoji "github.com/yuin/goldmark-emoji"
	highlighting "github.com/yuin/goldmark-highlighting"
	"github.com/yuin/goldmark/extension"
	"github.com/yuin/goldmark/parser"
	"github.com/yuin/goldmark/renderer/html"
	_ "go.jolheiser.com/chroma-catppuccin/chroma1"
)

var gm = func() goldmark.Markdown {
	var codeblockIdx int
	return goldmark.New(
		goldmark.WithExtensions(
			extension.GFM,
			highlighting.NewHighlighting(
				highlighting.WithStyle("catppuccin"),
				highlighting.WithFormatOptions(
					chromahtml.WithLineNumbers(true),
					chromahtml.LineNumbersInTable(true),
				),
				highlighting.WithCodeBlockOptions(func(ctx highlighting.CodeBlockContext) []chromahtml.Option {
					codeblockIdx++
					return []chromahtml.Option{
						chromahtml.LinkableLineNumbers(true, fmt.Sprintf("code%d-", codeblockIdx)),
					}
				}),
			),
			emoji.Emoji,
		),
		goldmark.WithParserOptions(
			parser.WithAutoHeadingID(),
		),
		goldmark.WithRendererOptions(
			html.WithHardWraps(),
		),
	)
}

// Convert transforms a markdown document into HTML
func Convert(r io.Reader) (string, error) {
	content, err := io.ReadAll(r)
	if err != nil {
		return "", err
	}
	var buf bytes.Buffer
	if err := gm().Convert(content, &buf); err != nil {
		return "", err
	}
	return buf.String(), nil
}