duration.go

package main

import (
	"fmt"
	"strconv"
	"strings"
	"time"
)

func parseDuration(durationStr string) (time.Duration, error) {
	parts := strings.Split(durationStr, ":")
	if len(parts) < 2 || len(parts) > 3 {
		return 0, fmt.Errorf("invalid duration format %q", durationStr)
	}

	var hours, minutes, seconds int
	var err error

	switch len(parts) {
	case 2: // "mm:ss" format
		minutes, err = strconv.Atoi(parts[0])
		if err != nil {
			return 0, fmt.Errorf("invalid minutes: %v", err)
		}
		seconds, err = strconv.Atoi(parts[1])
		if err != nil {
			return 0, fmt.Errorf("invalid seconds: %v", err)
		}
	case 3: // "hh:mm:ss" format
		hours, err = strconv.Atoi(parts[0])
		if err != nil {
			return 0, fmt.Errorf("invalid hours: %v", err)
		}
		minutes, err = strconv.Atoi(parts[1])
		if err != nil {
			return 0, fmt.Errorf("invalid minutes: %v", err)
		}
		seconds, err = strconv.Atoi(parts[2])
		if err != nil {
			return 0, fmt.Errorf("invalid seconds: %v", err)
		}
	}

	return time.Duration(hours)*time.Hour + time.Duration(minutes)*time.Minute + time.Duration(seconds)*time.Second, nil
}