package utils

import (
	"errors"
	"fmt"
	"strconv"
	"time"
)

// Parses a string to a duration
// Duration notations are an integer followed by a unit
// Units are s = second, m = minute, d = day, w = week, M = month, y = year
// Example 1y is the same as 1 year
func ParseDurationString(input string) (duration time.Duration, err error) {
	duration = 0
	err = nil
	matches := parseDurationRegexp.FindStringSubmatch(input)
	if len(matches) == 3 && matches[2] != "" {
		d, _ := strconv.Atoi(matches[1])
		switch matches[2] {
		case "y":
			duration = time.Duration(d) * Year
		case "M":
			duration = time.Duration(d) * Month
		case "w":
			duration = time.Duration(d) * Week
		case "d":
			duration = time.Duration(d) * Day
		case "h":
			duration = time.Duration(d) * Hour
		case "m":
			duration = time.Duration(d) * time.Minute
		case "s":
			duration = time.Duration(d) * time.Second
		}
	} else if input == "0" || len(matches) == 3 {
		seconds, err := strconv.Atoi(input)
		if err != nil {
			err = errors.New(fmt.Sprintf("could not convert the input string of %s into a duration: %s", input, err))
		} else {
			duration = time.Duration(seconds) * time.Second
		}
	} else if input != "" {
		// Throw this error if input is anything other than a blank string, blank string will default to a duration of nothing
		err = errors.New(fmt.Sprintf("could not convert the input string of %s into a duration", input))
	}
	return
}