From 7344ea2e865e69bb69eb9441723387f173ea3cf8 Mon Sep 17 00:00:00 2001
From: Niklas Fasching <niklas.fasching@gmail.com>
Date: Sun, 27 Mar 2022 01:16:01 +0100
Subject: [PATCH] Add version flag

go 1.18 embeds vcs info into binaries by default [1] allowing us to provide a
rudimentary version cmd in just a few lines. (version) vcs tags are not
embedded for now - just the commit hash should be good enough for now though.

[1] https://tip.golang.org/doc/go1.18
---
 go.mod  |  2 +-
 main.go | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/go.mod b/go.mod
index 83b1fde..ea085ed 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/niklasfasching/go-org
 
-go 1.17
+go 1.18
 
 require (
 	github.com/alecthomas/chroma v0.10.0
diff --git a/main.go b/main.go
index 94b710f..4cb20fa 100644
--- a/main.go
+++ b/main.go
@@ -6,6 +6,7 @@ import (
 	"io/ioutil"
 	"log"
 	"os"
+	"runtime/debug"
 	"strings"
 
 	"github.com/alecthomas/chroma"
@@ -37,6 +38,8 @@ func main() {
 		render(args)
 	case "blorg":
 		runBlorg(args)
+	case "version":
+		printVersion()
 	default:
 		log.Fatal(usage)
 	}
@@ -130,3 +133,19 @@ func highlightCodeBlock(source, lang string, inline bool) string {
 	}
 	return `<div class="highlight">` + "\n" + w.String() + "\n" + `</div>`
 }
+
+func printVersion() {
+	bi, ok := debug.ReadBuildInfo()
+	if !ok {
+		log.Fatal("not build info available")
+	}
+	revision, modified := "", false
+	for _, s := range bi.Settings {
+		if s.Key == "vcs.revision" {
+			revision = s.Value
+		} else if s.Key == "vcs.modified" {
+			modified = s.Value == "true"
+		}
+	}
+	log.Printf("%s (modified: %v)", revision, modified)
+}