updates

main.go

@@ -27,6 +27,12 @@ func main() {
 		namedStopwatch(args[0])
 	} else if len(args) == 2 && (args[0] == "clear" || args[0] == "-c" || args[0] == "--clear") {
 		clearStopwatch(args[1])
+	} else if len(args) == 2 && (args[0] == "timer" || args[0] == "-t" || args[0] == "--timer") {
+		d, err := time.ParseDuration(args[1])
+		if err != nil {
+			fmt.Println("Error parsing duration:", err)
+		}
+		timerUI(time.Now().Add(d))
 	}
 }
 
@@ -125,9 +131,35 @@ func stopwatchUI(startTime time.Time) {
 	}
 }
 
+func timerUI(startTime time.Time) {
+	stop := make(chan os.Signal, 1)
+	signal.Notify(stop, syscall.SIGINT, syscall.SIGTERM)
+
+	go func() {
+		<-stop
+		os.Exit(0)
+	}()
+
+	for {
+		elapsed := time.Until(startTime)
+		if elapsed.Milliseconds() == 0 {
+			break
+		}
+		fmt.Printf("\r%02dd %02dh %02dm %02ds %03dms",
+			elapsed/(24*time.Hour),
+			(elapsed%(24*time.Hour))/time.Hour,
+			(elapsed%time.Hour)/time.Minute,
+			(elapsed%time.Minute)/time.Second,
+			(elapsed%time.Second)/time.Millisecond)
+		time.Sleep(1 * time.Millisecond)
+	}
+}
+
 func printHelp() {
 	fmt.Println("Usage:")
 	fmt.Println("  stopwatch             - Start a quick stopwatch")
 	fmt.Println("  stopwatch [name]      - Start or view a named stopwatch")
-	fmt.Println("  stopwatch clear [name] - Remove a named stopwatch")
+	fmt.Println("  stopwatch -t [time]   - Start a quick timer")
+	fmt.Println("  stopwatch -c [name]   - Remove a named stopwatch")
+	fmt.Println("  stopwatch -h          - View help menu")
 }