From 1b3c7b4127c2125bfa0a780d4e65703f29ab0ee2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Guillaume=20H=C3=A9rail?= <guillaume@herail.net>
Date: Wed, 25 Jan 2023 13:08:08 +0100
Subject: [PATCH] fix: Properly handle macro when extracting Metadata
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

When a macro is set in the header, only the first line will be read and then
discarded. This makes sure we keep the macro in and stop processing metadata
when we hit a macro.

Co-authored-by: Manuel Rüger <manuel@rueg.eu>
---
 README.md        |  3 +++
 pkg/mark/meta.go | 11 +++++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 1e70b76..f288534 100644
--- a/README.md
+++ b/README.md
@@ -120,6 +120,9 @@ be replaced with specified template:
      <yaml-data> -->
 ```
 
+**NOTE**: Make sure to define your macros after your metadata (Title/Space), 
+mark will stop processing metadata if it hits a Macro.
+
 Capture groups can be defined in the macro's <regexp> which can be later
 referenced in the `<yaml-data>` using `${<number>}` syntax, where `<number>` is
 number of a capture group in regexp (`${0}` is used for entire regexp match),
diff --git a/pkg/mark/meta.go b/pkg/mark/meta.go
index 2f1a301..416182b 100644
--- a/pkg/mark/meta.go
+++ b/pkg/mark/meta.go
@@ -34,8 +34,9 @@ type Meta struct {
 }
 
 var (
-	reHeaderPatternV1 = regexp.MustCompile(`\[\]:\s*#\s*\(([^:]+):\s*(.*)\)`)
-	reHeaderPatternV2 = regexp.MustCompile(`<!--\s*([^:]+):\s*(.*)\s*-->`)
+	reHeaderPatternV1    = regexp.MustCompile(`\[\]:\s*#\s*\(([^:]+):\s*(.*)\)`)
+	reHeaderPatternV2    = regexp.MustCompile(`<!--\s*([^:]+):\s*(.*)\s*-->`)
+	reHeaderPatternMacro = regexp.MustCompile(`<!-- Macro: .*`)
 )
 
 func ExtractMeta(data []byte) (*Meta, []byte, error) {
@@ -58,6 +59,12 @@ func ExtractMeta(data []byte) (*Meta, []byte, error) {
 		if matches == nil {
 			matches = reHeaderPatternV1.FindStringSubmatch(line)
 			if matches == nil {
+				matches = reHeaderPatternMacro.FindStringSubmatch(line)
+				// If we have a match, then we started reading a macro.
+				// We want to keep it in the document for it to be read by ExtractMacros
+				if matches != nil {
+					offset -= len(line) + 1
+				}
 				break
 			}