all: handle empty preamble

If the document contains empty preamble do not output the HTML wrapper of
it.

8 files changed, 34 insertions, 21 deletions

diff --git a/document.go b/document.go
index 2b1cd91..97c8171 100644
--- a/document.go
+++ b/document.go
@@ -260,6 +260,22 @@ func (doc *Document) generateClasses() {
 	}
 }
 
+func (doc *Document) haveHeader() bool {
+	if len(doc.Authors) > 0 {
+		return true
+	}
+	if len(doc.Revision.Number) > 0 {
+		return true
+	}
+	if len(doc.Revision.Date) > 0 {
+		return true
+	}
+	if len(doc.Revision.Remark) > 0 {
+		return true
+	}
+	return false
+}
+
 func (doc *Document) toHTMLBody(buf *bytes.Buffer, withHeaderFooter bool) {
 	var (
 		ok bool
diff --git a/document_parser.go b/document_parser.go
index 1117b99..3ccfa0f 100644
--- a/document_parser.go
+++ b/document_parser.go
@@ -136,17 +136,22 @@ func (docp *documentParser) hasPreamble() bool {
 	var (
 		start = docp.lineNum
 
-		line []byte
-		kind int
+		notEmtpy int
+		line     []byte
+		kind     int
 	)
 	for ; start < len(docp.lines); start++ {
 		line = docp.lines[start]
+		if len(line) == 0 {
+			continue
+		}
 		kind, _, _ = whatKindOfLine(line)
 		if kind == elKindSectionL1 || kind == elKindSectionL2 ||
 			kind == elKindSectionL3 || kind == elKindSectionL4 ||
 			kind == elKindSectionL5 {
-			return true
+			return notEmtpy > 0
 		}
+		notEmtpy++
 	}
 	return false
 }
diff --git a/html_backend.go b/html_backend.go
index b3f5adb..100fab1 100644
--- a/html_backend.go
+++ b/html_backend.go
@@ -979,6 +979,8 @@ func htmlWriteHeader(doc *Document, out io.Writer) {
 	fmt.Fprint(out, "\n<div id=\"header\">")
 
 	var (
+		haveHeader = doc.haveHeader()
+
 		author *Author
 		prefix string
 		sep    string
@@ -996,7 +998,9 @@ func htmlWriteHeader(doc *Document, out io.Writer) {
 		}
 	}
 
-	fmt.Fprint(out, "\n<div class=\"details\">")
+	if haveHeader {
+		fmt.Fprint(out, "\n<div class=\"details\">")
+	}
 
 	var authorID, emailID string
 	for x, author = range doc.Authors {
@@ -1042,7 +1046,9 @@ func htmlWriteHeader(doc *Document, out io.Writer) {
 		fmt.Fprintf(out, "\n<br><span id=%q>%s</span>",
 			metaNameRevRemark, doc.Revision.Remark)
 	}
-	fmt.Fprint(out, "\n</div>")
+	if haveHeader {
+		fmt.Fprint(out, "\n</div>")
+	}
 
 	if doc.tocIsEnabled && (doc.tocPosition == `` ||
 		doc.tocPosition == metaValueAuto ||
diff --git a/testdata/document_title_test.txt b/testdata/document_title_test.txt
index f5dbdf9..14098ca 100644
--- a/testdata/document_title_test.txt
+++ b/testdata/document_title_test.txt
@@ -7,8 +7,6 @@ output_call: htmlWriteHeader
 
 <div id="header">
 <h1>Main: sub</h1>
-<div class="details">
-</div>
 </div>
 
 >>> Without space after separator
@@ -18,8 +16,6 @@ output_call: htmlWriteHeader
 
 <div id="header">
 <h1>Main:sub</h1>
-<div class="details">
-</div>
 </div>
 
 >>> With multiple separator after separator
@@ -29,8 +25,6 @@ output_call: htmlWriteHeader
 
 <div id="header">
 <h1>a: b: c</h1>
-<div class="details">
-</div>
 </div>
 
 >>> With custom separator
@@ -41,6 +35,4 @@ output_call: htmlWriteHeader
 
 <div id="header">
 <h1>Mainx sub</h1>
-<div class="details">
-</div>
 </div>
diff --git a/testdata/header_with_empty_line_test.txt b/testdata/header_with_empty_line_test.txt
index f36f99b..c4a4a63 100644
--- a/testdata/header_with_empty_line_test.txt
+++ b/testdata/header_with_empty_line_test.txt
@@ -13,8 +13,6 @@ Below is empty line with spaces.
 <<<
 
 <div id="header">
-<div class="details">
-</div>
 </div>
 <div id="content">
 <div class="paragraph">
diff --git a/testdata/meta_showtitle_test.txt b/testdata/meta_showtitle_test.txt
index e534c1c..163f264 100644
--- a/testdata/meta_showtitle_test.txt
+++ b/testdata/meta_showtitle_test.txt
@@ -7,8 +7,6 @@ output_call: ToHTMLBody
 
 <div id="header">
 <h1>Abc</h1>
-<div class="details">
-</div>
 </div>
 <div id="content">
 </div>
@@ -24,8 +22,6 @@ output_call: ToHTMLBody
 <<< With meta showtitle off
 
 <div id="header">
-<div class="details">
-</div>
 </div>
 <div id="content">
 </div>
diff --git a/testdata/test.exp.html b/testdata/test.exp.html
index 6af6df4..f0a36d0 100644
--- a/testdata/test.exp.html
+++ b/testdata/test.exp.html
@@ -2995,7 +2995,7 @@ this sidebar.</p>
 <div id="footer">
 <div id="footer-text">
  1.1.1<br>
-Last updated 2022-10-18 00:21:57 +0700
+Last updated 2023-03-02 20:49:28 +0700
 </div>
 </div>
 </body>
diff --git a/testdata/test.got.html b/testdata/test.got.html
index 512f9a7..28cba38 100644
--- a/testdata/test.got.html
+++ b/testdata/test.got.html
@@ -2997,7 +2997,7 @@ this sidebar.</p>
 <div id="footer">
 <div id="footer-text">
  1.1.1<br>
-Last updated 2022-10-18 00:21:58 +0700
+Last updated 2023-03-02 20:49:28 +0700
 </div>
 </div>
 </body>