Implemented proper conversion of links to local markdown files into html links

internal/convert/convert.go

@@ -1,12 +1,14 @@
 package convert
 
 import (
+	"fmt"
 	"io"
 	"os"
 	"path/filepath"
 	"strings"
 
 	"github.com/gomarkdown/markdown"
+	"github.com/gomarkdown/markdown/ast"
 	"github.com/gomarkdown/markdown/html"
 	"github.com/gomarkdown/markdown/parser"
 )
@@ -19,13 +21,64 @@ func MdToHTML(md []byte) ([]byte, error) {
 	doc := p.Parse(md)
 
 	// build HTML renderer
-	htmlFlags := html.CommonFlags | html.HrefTargetBlank
+	htmlFlags := html.CommonFlags | html.HrefTargetBlank | html.CompletePage
 	opts := html.RendererOptions{Flags: htmlFlags}
-	renderer := html.NewRenderer(opts)
+	renderer := newZonaRenderer(opts)
 
 	return markdown.Render(doc, renderer), nil
 }
 
+// PathIsValid checks if a path is valid.
+// If requireFile is set, directories are not considered valid.
+func PathIsValid(path string, requireFile bool) bool {
+	s, err := os.Stat(path)
+	if os.IsNotExist(err) {
+		return false
+	} else if requireFile {
+		// fmt.Printf("Directory status: %s\n", strconv.FormatBool(s.IsDir()))
+		return !s.IsDir()
+	}
+	return err == nil
+}
+
+func processLink(p string) string {
+	fmt.Println("Processing link...")
+	ext := filepath.Ext(p)
+	// Only process if it points to an existing, local markdown file
+	if ext == ".md" && filepath.IsLocal(p) {
+		fmt.Println("Markdown link detected...")
+		return ChangeExtension(p, ".html")
+	} else {
+		return p
+	}
+}
+
+func renderLink(w io.Writer, l *ast.Link, entering bool) {
+	if entering {
+		destPath := processLink(string(l.Destination))
+		fmt.Fprintf(w, `<a href="%s"`, destPath)
+		for _, attr := range html.BlockAttrs(l) {
+			fmt.Fprintf(w, ` %s`, attr)
+		}
+		io.WriteString(w, ">")
+	} else {
+		io.WriteString(w, "</a>")
+	}
+}
+
+func htmlRenderHook(w io.Writer, node ast.Node, entering bool) (ast.WalkStatus, bool) {
+	if link, ok := node.(*ast.Link); ok {
+		renderLink(w, link, entering)
+		return ast.GoToNext, true
+	}
+	return ast.GoToNext, false
+}
+
+func newZonaRenderer(opts html.RendererOptions) *html.Renderer {
+	opts.RenderNodeHook = htmlRenderHook
+	return html.NewRenderer(opts)
+}
+
 // WriteFile writes a given byte array to the given path.
 func WriteFile(b []byte, p string) error {
 	f, err := os.Create(p)