3 files changed, 149 insertions, 0 deletions
diff --git a/internal/tailwind/extension.go b/internal/tailwind/extension.go
new file mode 100644
index 0000000..c3254cc
--- /dev/null
+++ b/internal/tailwind/extension.go
@@ -0,0 +1,21 @@
+package tailwind
+
+import (
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/parser"
+	"github.com/yuin/goldmark/util"
+)
+
+type TailwindExtension struct{}
+
+func NewTailwindExtension() goldmark.Extender {
+	return &TailwindExtension{}
+}
+
+func (e *TailwindExtension) Extend(m goldmark.Markdown) {
+	m.Parser().AddOptions(
+		parser.WithASTTransformers(
+			util.Prioritized(&TailwindTransformer{}, 500),
+		),
+	)
+}
diff --git a/internal/tailwind/link_renderer.go b/internal/tailwind/link_renderer.go
new file mode 100644
index 0000000..ff3d437
--- /dev/null
+++ b/internal/tailwind/link_renderer.go
@@ -0,0 +1,49 @@
+package tailwind
+
+import (
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/renderer/html"
+	"github.com/yuin/goldmark/util"
+)
+
+type CustomLinkRenderer struct {
+	html.Config
+}
+
+func NewCustomLinkRenderer(opts ...html.Option) renderer.NodeRenderer {
+	r := &CustomLinkRenderer{
+		Config: html.NewConfig(),
+	}
+	for _, opt := range opts {
+		opt.SetHTMLOption(&r.Config)
+	}
+	return r
+}
+
+func (r *CustomLinkRenderer) renderLink(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	n := node.(*ast.Link)
+	if entering {
+		_, _ = w.WriteString("<a href=\"")
+		if r.Unsafe || !html.IsDangerousURL(n.Destination) {
+			_, _ = w.Write(util.EscapeHTML(util.URLEscape(n.Destination, true)))
+		}
+		_, _ = w.WriteString(`"`)
+		if n.Title != nil {
+			_, _ = w.WriteString(` title="`)
+			_, _ = w.Write(util.EscapeHTML(n.Title))
+			_, _ = w.WriteString(`"`)
+		}
+		if n.Attributes() != nil {
+			html.RenderAttributes(w, n, nil)
+		}
+		_, _ = w.WriteString(">")
+	} else {
+		_, _ = w.WriteString("</a>")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *CustomLinkRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
+	reg.Register(ast.KindLink, r.renderLink)
+}
diff --git a/internal/tailwind/transformer.go b/internal/tailwind/transformer.go
new file mode 100644
index 0000000..f90489f
--- /dev/null
+++ b/internal/tailwind/transformer.go
@@ -0,0 +1,79 @@
+package tailwind
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/parser"
+	"github.com/yuin/goldmark/text"
+)
+
+type TailwindTransformer struct{}
+
+func (t *TailwindTransformer) Transform(node *ast.Document, reader text.Reader, pc parser.Context) {
+	ast.Walk(node, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
+		if !entering {
+			return ast.WalkContinue, nil
+		}
+
+		switch node := n.(type) {
+		case *ast.Heading:
+			classes := map[int]string{
+				1: "font-gentium text-4xl font-bold text-main-hard mb-3 tracking-[.0125rem]",
+				2: "font-gentium text-3xl font-bold text-main-hard mb-1 tracking-[.0125rem]",
+				3: "font-gentium text-2xl font-medium text-main-hard mb-0.8 tracking-[.0125rem]",
+				4: "font-gentium text-xl font-medium text-main-medium mb-0.5 tracking-[.0125rem]",
+				5: "font-gentium text-base font-medium text-main-medium mb-0.5 italic tracking-[.0125rem]",
+				6: "font-gentium text-base font-medium text-secondary mb-0.5",
+			}
+			if class, ok := classes[node.Level]; ok {
+				node.SetAttribute([]byte("class"), []byte(class))
+			}
+
+		case *ast.Paragraph:
+			node.SetAttribute([]byte("class"), []byte("text-base/[2] font-gentium tracking-[.0125rem] -indent-8 ml-4 mb-8"))
+
+		case *ast.List:
+			if node.IsOrdered() {
+				node.SetAttribute([]byte("class"), []byte("list-decimal list-inside space-y-2 mb-4 pl-8"))
+			} else {
+				node.SetAttribute([]byte("class"), []byte("list-disc list-inside space-y-2 mb-4 pl-8"))
+			}
+
+		case *ast.ListItem:
+			node.SetAttribute([]byte("class"), []byte("text-base/[2] font-gentium tracking-[.0125rem]"))
+
+		case *ast.Blockquote:
+			node.SetAttribute([]byte("class"), []byte("border-l-[0.125rem] border-main-medium bg-paper bg-background-dark p-1 mb-2 italic font-thin"))
+
+		case *ast.CodeSpan:
+			node.SetAttribute([]byte("class"), []byte("bg-paper bg-background-dark"))
+
+		case *ast.CodeBlock, *ast.FencedCodeBlock:
+			node.SetAttribute([]byte("class"), []byte("bg-paper bg-background-dark p-1 rounded-lg overflow-x-auto mb-4"))
+
+		case *ast.Link:
+			if bytes.HasPrefix(node.Destination, []byte{'.', '/'}) {
+				onclickAttr := fmt.Appendf(make([]byte, 0, 21+len(node.Destination)), "return changeUrl('%s');", node.Destination)
+				node.SetAttribute([]byte("onclick"), onclickAttr)
+			}
+			node.SetAttribute([]byte("class"), []byte("text-secondary hover:text-main-hard underline"))
+
+		case *ast.Image:
+			node.SetAttribute([]byte("class"), []byte("max-w-full h-auto rounded-lg shadow-lg mb-4"))
+
+		case *ast.Emphasis:
+			switch node.Level {
+			case 1:
+				node.SetAttribute([]byte("class"), []byte("italic font-thin"))
+			case 2:
+				node.SetAttribute([]byte("class"), []byte("font-bold"))
+			case 3:
+				node.SetAttribute([]byte("class"), []byte("italic font-bold"))
+			}
+		}
+
+		return ast.WalkContinue, nil
+	})
+}