From 998cbf1cc44f68895f00aa98082dd8c8930ddd81 Mon Sep 17 00:00:00 2001
From: Cristian Dominguez <cristiand391@users.noreply.github.com>
Date: Fri, 30 Oct 2020 12:14:36 -0300
Subject: [PATCH] Ignore YAML frontmatter

---
 main.go        |  3 +++
 ui/ui.go       |  2 ++
 utils/utils.go | 19 +++++++++++++++++++
 3 files changed, 24 insertions(+)
 create mode 100644 utils/utils.go

diff --git a/main.go b/main.go
index 9e6b402..f540cfc 100644
--- a/main.go
+++ b/main.go
@@ -22,6 +22,7 @@ import (
 	"github.com/charmbracelet/charm/ui/common"
 	"github.com/charmbracelet/glamour"
 	"github.com/charmbracelet/glow/ui"
+	"github.com/charmbracelet/glow/utils"
 )
 
 var (
@@ -195,6 +196,8 @@ func executeArg(cmd *cobra.Command, arg string, w io.Writer) error {
 		return err
 	}
 
+	b = utils.RemoveFrontmatter(b)
+
 	// render
 	var baseURL string
 	u, err := url.ParseRequestURI(src.URL)
diff --git a/ui/ui.go b/ui/ui.go
index 0e82980..8fd04a0 100644
--- a/ui/ui.go
+++ b/ui/ui.go
@@ -15,6 +15,7 @@ import (
 	"github.com/charmbracelet/charm"
 	"github.com/charmbracelet/charm/keygen"
 	"github.com/charmbracelet/charm/ui/common"
+	"github.com/charmbracelet/glow/utils"
 	"github.com/muesli/gitcha"
 	te "github.com/muesli/termenv"
 )
@@ -355,6 +356,7 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 
 	case fetchedMarkdownMsg:
 		m.pager.currentDocument = *msg
+		msg.Body = string(utils.RemoveFrontmatter([]byte(msg.Body)))
 		cmds = append(cmds, renderWithGlamour(m.pager, msg.Body))
 
 	case contentRenderedMsg:
diff --git a/utils/utils.go b/utils/utils.go
new file mode 100644
index 0000000..e03298c
--- /dev/null
+++ b/utils/utils.go
@@ -0,0 +1,19 @@
+package utils
+
+import "regexp"
+
+func RemoveFrontmatter(content []byte) []byte {
+	if frontmatterBoundaries := detectFrontmatter(content); frontmatterBoundaries[0] == 0 {
+		return content[frontmatterBoundaries[1]:]
+	}
+	return content
+}
+
+var yamlPattern = regexp.MustCompile(`(?m)^---\r?\n(\s*\r?\n)?`)
+
+func detectFrontmatter(c []byte) []int {
+	if matches := yamlPattern.FindAllIndex(c, 2); len(matches) > 1 {
+		return []int{matches[0][0], matches[1][1]}
+	}
+	return []int{-1, -1}
+}