Indent dependening on the minimum header

This update should address
ekalinin#8.

main.go

@@ -171,27 +171,38 @@ func GrabToc(html string, absPath string, depth int) *GHToc {
 	r := regexp.MustCompile(re)
 
 	toc := GHToc{}
-	groups := make(map[string]string)
+	minHeaderNum := 6
+	var groups []map[string]string
 	for _, match := range r.FindAllStringSubmatch(html, -1) {
+		group := make(map[string]string)
 		// fill map for groups
 		for i, name := range r.SubexpNames() {
 			if i == 0 || name == "" {
 				continue
 			}
-			groups[name] = removeStuf(match[i])
+			group[name] = removeStuf(match[i])
 		}
+		// update minimum header number
+		n, _ := strconv.Atoi(group["num"])
+		if n < minHeaderNum {
+			minHeaderNum = n
+		}
+		groups = append(groups, group)
+	}
+
+	for _, group := range groups {
 		// format result
-		n, _ := strconv.Atoi(groups["num"])
+		n, _ := strconv.Atoi(group["num"])
 		if depth > 0 && n > depth {
 			continue
 		}
 
-		link := groups["href"]
+		link := group["href"]
 		if len(absPath) > 0 {
 			link = absPath + link
 		}
-		tocItem := strings.Repeat("  ", n-1) + "* " +
-			"[" + EscapeSpecChars(removeStuf(groups["name"])) + "]" +
+		tocItem := strings.Repeat("  ", n-minHeaderNum) + "* " +
+			"[" + EscapeSpecChars(removeStuf(group["name"])) + "]" +
 			"(" + link + ")"
 		//fmt.Println(tocItem)
 		toc = append(toc, tocItem)

main_test.go

@@ -168,7 +168,7 @@ func Test_GrabTocWithAbspath(t *testing.T) {
 
 func Test_EscapedChars(t *testing.T) {
 	tocExpected := []string{
-		"  * [mod\\_\\*](#mod_)",
+		"* [mod\\_\\*](#mod_)",
 	}
 
 	toc := *GrabToc(`
@@ -184,3 +184,29 @@ func Test_EscapedChars(t *testing.T) {
 		t.Error("Res :", toc, "\nExpected     :", tocExpected)
 	}
 }
+
+func Test_MinHeaderNumber(t *testing.T) {
+	tocExpected := []string{
+		"* [foo](#foo)",
+		"  * [bar](#bar)",
+	}
+
+	toc := *GrabToc(`
+		<h3>
+			<a id="user-content-" class="anchor" href="#foo" aria-hidden="true">
+				<span class="octicon octicon-link"></span>
+			</a>
+			foo
+		</h3>
+		<h4>
+			<a id="user-content-" class="anchor" href="#bar" aria-hidden="true">
+				<span class="octicon octicon-link"></span>
+			</a>
+			bar
+		</h3>
+		`, "", 0)
+
+	if toc[0] != tocExpected[0] {
+		t.Error("Res :", toc, "\nExpected     :", tocExpected)
+	}
+}