Move code rendering to the backend & frontend improvements (#176)

Added Chroma & Goldmark

Added Mermaidjs

More languages supported

Add default values for gist links input

Added copy code from markdown blocks

internal/render/markdown.go

@@ -0,0 +1,47 @@
+package render
+
+import (
+	"bytes"
+	"github.com/alecthomas/chroma/v2/formatters/html"
+	"github.com/thomiceli/opengist/internal/db"
+	"github.com/thomiceli/opengist/internal/git"
+	"github.com/yuin/goldmark"
+	emoji "github.com/yuin/goldmark-emoji"
+	highlighting "github.com/yuin/goldmark-highlighting/v2"
+	"github.com/yuin/goldmark/extension"
+	"go.abhg.dev/goldmark/mermaid"
+)
+
+func MarkdownGistPreview(gist *db.Gist) (RenderedGist, error) {
+	var buf bytes.Buffer
+	err := newMarkdown().Convert([]byte(gist.Preview), &buf)
+
+	return RenderedGist{
+		Gist: gist,
+		HTML: buf.String(),
+	}, err
+}
+
+func MarkdownFile(file *git.File) (RenderedFile, error) {
+	var buf bytes.Buffer
+	err := newMarkdown().Convert([]byte(file.Content), &buf)
+
+	return RenderedFile{
+		File: file,
+		HTML: buf.String(),
+		Type: "Markdown",
+	}, err
+}
+
+func newMarkdown() goldmark.Markdown {
+	return goldmark.New(
+		goldmark.WithExtensions(
+			extension.GFM,
+			highlighting.NewHighlighting(
+				highlighting.WithStyle("catppuccin-latte"),
+				highlighting.WithFormatOptions(html.WithClasses(true))),
+			emoji.Emoji,
+			&mermaid.Extender{},
+		),
+	)
+}