all: embed the HTML template and the stylesheet

The parameter for template either in Convert or Generate functions or
in CLI now become pure optional, not default to "templates/html.tmpl"
anymore.

This will minimize steps for user to setup or run the library or program.

1 files changed, 11 insertions, 6 deletions

diff --git a/filehtml.go b/filehtml.go
index 7eeda71..fb11eee 100644
--- a/filehtml.go
+++ b/filehtml.go
@@ -13,12 +13,13 @@ import (
 // fileHTML represent an HTML metadata for header and its body.
 //
 type fileHTML struct {
-	Title    string
-	Author   string
-	Date     string
-	Styles   []string
-	Body     template.HTML
-	Metadata map[string]string
+	Title       string
+	Author      string
+	Date        string
+	EmbeddedCSS *template.CSS
+	Styles      []string
+	Body        template.HTML
+	Metadata    map[string]string
 
 	path    string
 	rawBody strings.Builder
@@ -31,6 +32,7 @@ func (fhtml *fileHTML) reset() {
 	fhtml.Title = ""
 	fhtml.Author = ""
 	fhtml.Date = ""
+	fhtml.EmbeddedCSS = nil
 	fhtml.Styles = fhtml.Styles[:0]
 	fhtml.Body = template.HTML("")
 
@@ -59,6 +61,9 @@ func (fhtml *fileHTML) unpackMarkup(fa *fileMarkup) {
 			fhtml.Metadata[k] = v.(string)
 		}
 	}
+	if len(fhtml.Styles) == 0 {
+		fhtml.EmbeddedCSS = embeddedCSS()
+	}
 
 	fhtml.Body = template.HTML(fhtml.rawBody.String()) // nolint:gosec
 }