turn download into a subcommand

main.go

@@ -120,19 +120,10 @@ func say(enabled bool, format string, args ...any) {
 	fmt.Printf(format+"\n", args...)
 }
 
-func main() {
+func downloadUgoiraCmd(args []string, flags CliFlags) {
-	var flags CliFlags
-	flag.StringVar(&flags.outputFileName, "o", "", "Ugoira output file name")
-	flag.StringVar(&flags.manifestFileName, "M", "", "Ugoira manifest output file name")
-	flag.StringVar(&flags.userAgent, "A", "", "User agent to use when doing GET requests")
-	flag.BoolVar(&flags.verbose, "v", false, "Enable verbosity")
-	flag.Parse()
-
-	args := flag.Args()
 	if len(args) == 0 {
 		die("expected post ID")
 	}
-
 	postIdStr := args[0]
 	postId, err := strconv.ParseUint(postIdStr, 10, 0)
 	if err != nil {
@@ -141,3 +132,31 @@ func main() {
 	say(flags.verbose, "Working on post %d", postId)
 	getUgoira(PostId(postId), flags)
 }
+
+func main() {
+	var flags CliFlags
+	downloadCmd := flag.NewFlagSet("download", flag.ExitOnError)
+	u2vCmd := flag.NewFlagSet("u2v", flag.ExitOnError)
+
+	downloadCmd.StringVar(&flags.outputFileName, "o", "", "Ugoira output file name")
+	downloadCmd.StringVar(&flags.manifestFileName, "M", "", "Ugoira manifest output file name")
+	downloadCmd.StringVar(&flags.userAgent, "A", "", "User agent to use when doing GET requests")
+	downloadCmd.BoolVar(&flags.verbose, "v", false, "Enable verbosity")
+
+	if len(os.Args) < 2 {
+		die("expected command")
+	}
+
+	switch os.Args[1] {
+	case "download", "down", "d":
+		downloadCmd.Parse(os.Args[2:])
+		restArgs := downloadCmd.Args()
+		downloadUgoiraCmd(restArgs, flags)
+	case "u2v":
+		u2vCmd.Parse(os.Args[2:])
+		//restArgs := u2vCmd.Args()
+		fmt.Println("convert command")
+	default:
+		die("invalid command '%s'", os.Args[1])
+	}
+}