chore: implement part of html renderer

plugin/gomark/renderer/html/html.go

@@ -0,0 +1,87 @@
+package html
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/usememos/memos/plugin/gomark/ast"
+)
+
+// HTMLRenderer is a simple renderer that converts AST to HTML.
+// nolint
+type HTMLRenderer struct {
+	output  *bytes.Buffer
+	context *renderContext
+}
+
+type renderContext struct {
+}
+
+// NewHTMLRenderer creates a new HTMLRenderer.
+func NewHTMLRenderer() *HTMLRenderer {
+	return &HTMLRenderer{
+		output:  new(bytes.Buffer),
+		context: &renderContext{},
+	}
+}
+
+// RenderNode renders a single AST node to HTML.
+func (r *HTMLRenderer) RenderNode(node ast.Node) {
+	prevSibling, nextSibling := node.GetPrevSibling(), node.GetNextSibling()
+
+	switch n := node.(type) {
+	case *ast.LineBreak:
+		r.output.WriteString("<br>")
+	case *ast.Paragraph:
+		r.output.WriteString("<p>")
+		r.RenderNodes(n.Children)
+		r.output.WriteString("</p>")
+	case *ast.CodeBlock:
+		r.output.WriteString("<pre><code>")
+		r.output.WriteString(n.Content)
+		r.output.WriteString("</code></pre>")
+	case *ast.Heading:
+		r.output.WriteString(fmt.Sprintf("<h%d>", n.Level))
+		r.RenderNodes(n.Children)
+		r.output.WriteString(fmt.Sprintf("</h%d>", n.Level))
+	case *ast.HorizontalRule:
+		r.output.WriteString("<hr>")
+	case *ast.Blockquote:
+		if prevSibling == nil || prevSibling.Type() != ast.NodeTypeBlockquote {
+			r.output.WriteString("<blockquote>")
+		}
+		r.RenderNodes(n.Children)
+		if nextSibling != nil && nextSibling.Type() == ast.NodeTypeBlockquote {
+			r.RenderNode(nextSibling)
+		}
+		if prevSibling == nil || prevSibling.Type() != ast.NodeTypeBlockquote {
+			r.output.WriteString("</blockquote>")
+		}
+	case *ast.Text:
+		r.output.WriteString(n.Content)
+	default:
+		// Handle other block types if needed.
+	}
+}
+
+// RenderNodes renders a slice of AST nodes to HTML.
+func (r *HTMLRenderer) RenderNodes(nodes []ast.Node) {
+	for _, node := range nodes {
+		prevSibling := node.GetPrevSibling()
+		if prevSibling != nil {
+			if prevSibling.Type() == node.Type() {
+				if node.Type() == ast.NodeTypeBlockquote {
+					continue
+				}
+			}
+		}
+
+		r.RenderNode(node)
+	}
+}
+
+// Render renders the AST to HTML.
+func (r *HTMLRenderer) Render(astRoot []ast.Node) string {
+	r.RenderNodes(astRoot)
+	return r.output.String()
+}