add -auto-archive flag

README.md

@@ -20,9 +20,21 @@ $ notico [-channel "#foo"]
 - channel_rename
 - channel_archive
 - channel_unarchive
+- channel_left
 - team_join
 - bot_added
 
+## Options
+
+```
+Usage of notico
+  -auto-archive
+    	Archive the channel which includes nobody automatically
+  -channel string
+    	Channel to post notification message (default "#admins")
+  -version
+    	Show versrion
+```
 
 ## LICENSE
 

main.go

@@ -20,9 +20,14 @@ var (
 )
 
 func main() {
-	var showVersion bool
+	var (
+		showVersion bool
+		autoArchive bool
+	)
 	flag.StringVar(&channel, "channel", "#admins", "Channel to post notification message")
 	flag.BoolVar(&showVersion, "version", false, "Show versrion")
+	flag.BoolVar(&autoArchive, "auto-archive", false, "Archive the channel which includes nobody automatically")
+	flag.Parse()
 	if showVersion {
 		fmt.Println("notico version", version)
 		return
@@ -71,6 +76,9 @@ Loop:
 				domain = ev.Info.Team.Domain
 				log.Printf("Team Info: %#v", ev.Info.Team)
 			case *slack.ChannelLeftEvent:
+				if !autoArchive {
+					continue
+				}
 				info, err := api.GetChannelInfo(ev.Channel)
 				if err != nil {
 					log.Printf("failed to get channel info: %s", err)