Removal procedure for slash commands example (#1103)

Remove commands on exit.

examples/slash_commands/main.go

@@ -363,24 +363,48 @@ func init() {
 
 func main() {
 	s.AddHandler(func(s *discordgo.Session, r *discordgo.Ready) {
-		log.Println("Bot is up!")
+		log.Printf("Logged in as: %v#%v", s.State.User.Username, s.State.User.Discriminator)
 	})
 	err := s.Open()
 	if err != nil {
 		log.Fatalf("Cannot open the session: %v", err)
 	}
 
-	for _, v := range commands {
-		_, err := s.ApplicationCommandCreate(s.State.User.ID, *GuildID, v)
+	log.Println("Adding commands...")
+	registeredCommands := make([]*discordgo.ApplicationCommand, len(commands))
+	for i, v := range commands {
+		cmd, err := s.ApplicationCommandCreate(s.State.User.ID, *GuildID, v)
 		if err != nil {
 			log.Panicf("Cannot create '%v' command: %v", v.Name, err)
 		}
+		registeredCommands[i] = cmd
 	}
 
 	defer s.Close()
 
 	stop := make(chan os.Signal, 1)
 	signal.Notify(stop, os.Interrupt)
+	log.Println("Press Ctrl+C to exit")
 	<-stop
+
+	if *RemoveCommands {
+		log.Println("Removing commands...")
+		// // We need to fetch the commands, since deleting requires the command ID.
+		// // We are doing this from the returned commands on line 375, because using
+		// // this will delete all the commands, which might not be desirable, so we
+		// // are deleting only the commands that we added.
+		// registeredCommands, err := s.ApplicationCommands(s.State.User.ID, *GuildID)
+		// if err != nil {
+		// 	log.Fatalf("Could not fetch registered commands: %v", err)
+		// }
+
+		for _, v := range registeredCommands {
+			err := s.ApplicationCommandDelete(s.State.User.ID, *GuildID, v.ID)
+			if err != nil {
+				log.Panicf("Cannot delete '%v' command: %v", v.Name, err)
+			}
+		}
+	}
+
 	log.Println("Gracefully shutdowning")
 }