From d9242c9a7220e194b1fe4165cf3669d3b642e2e7 Mon Sep 17 00:00:00 2001
From: Nicolas Martin <penguwin@penguwin.eu>
Date: Wed, 16 Dec 2020 16:23:58 +0100
Subject: [PATCH] Expand the path for a specified style file

---
 go.mod         |  1 +
 main.go        | 19 ++++++++++++++++---
 utils/utils.go | 16 +++++++++++++++-
 3 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/go.mod b/go.mod
index a2e7086..fbf0a23 100644
--- a/go.mod
+++ b/go.mod
@@ -14,6 +14,7 @@ require (
 	github.com/mattn/go-runewidth v0.0.9
 	github.com/meowgorithm/babyenv v1.3.0
 	github.com/microcosm-cc/bluemonday v1.0.4 // indirect
+	github.com/mitchellh/go-homedir v1.1.0
 	github.com/muesli/gitcha v0.1.2-0.20200908172931-5aa4fdccf2f6
 	github.com/muesli/go-app-paths v0.2.1
 	github.com/muesli/reflow v0.2.0
diff --git a/main.go b/main.go
index 1584de0..f506f9d 100644
--- a/main.go
+++ b/main.go
@@ -135,13 +135,23 @@ func sourceFromArg(arg string) (*source, error) {
 	return &source{r, u}, err
 }
 
-func validateOptions(cmd *cobra.Command) {
+func validateOptions(cmd *cobra.Command) error {
 	// grab config values from Viper
-	style = viper.GetString("style")
 	width = viper.GetUint("width")
 	localOnly = viper.GetBool("local")
 	mouse = viper.GetBool("mouse")
 
+	// validate the glamour style
+	style = viper.GetString("style")
+	if style != "auto" && glamour.DefaultStyles[style] == nil {
+		style = utils.ExpandPath(style)
+		if _, err := os.Stat(style); os.IsNotExist(err) {
+			return fmt.Errorf("Specified style does not exist: %s", style)
+		} else if err != nil {
+			return err
+		}
+	}
+
 	isTerminal := terminal.IsTerminal(int(os.Stdout.Fd()))
 	// We want to use a special no-TTY style, when stdout is not a terminal
 	// and there was no specific style passed by arg
@@ -163,11 +173,14 @@ func validateOptions(cmd *cobra.Command) {
 	if width == 0 {
 		width = 80
 	}
+	return nil
 }
 
 func execute(cmd *cobra.Command, args []string) error {
 	initConfig()
-	validateOptions(cmd)
+	if err := validateOptions(cmd); err != nil {
+		return err
+	}
 
 	if len(args) == 0 {
 		return executeArg(cmd, "", os.Stdout)
diff --git a/utils/utils.go b/utils/utils.go
index e03298c..8146f82 100644
--- a/utils/utils.go
+++ b/utils/utils.go
@@ -1,6 +1,11 @@
 package utils
 
-import "regexp"
+import (
+	"os"
+	"regexp"
+
+	"github.com/mitchellh/go-homedir"
+)
 
 func RemoveFrontmatter(content []byte) []byte {
 	if frontmatterBoundaries := detectFrontmatter(content); frontmatterBoundaries[0] == 0 {
@@ -17,3 +22,12 @@ func detectFrontmatter(c []byte) []int {
 	}
 	return []int{-1, -1}
 }
+
+// Expands tilde and all environment variables from the given path.
+func ExpandPath(path string) string {
+	s, err := homedir.Expand(path)
+	if err == nil {
+		return os.ExpandEnv(s)
+	}
+	return os.ExpandEnv(path)
+}