Function GetNextApplicableMondayOfNWeeks

coderd/schedule/autostop.go:365–393

GetNextApplicableMondayOfNWeeks gets the next Monday (0:00) of the next week divisible by n since epoch. If the next applicable week is invalid for any reason, the week after will be used instead (up to 2 attempts). If the current week is divisible by n, then the provided time is returned as is. T

(now time.Time, n int64)

//
// The timezone embedded in the time object is used to determine the epoch.
func GetNextApplicableMondayOfNWeeks(now time.Time, n int64) (time.Time, error) {
	// Get the current week number.
	weeksSinceEpoch, err := WeeksSinceEpoch(now)
	if err != nil {
		return time.Time{}, xerrors.Errorf("get current week number: %w", err)
	}

	// Get the next week divisible by n.
	remainder := weeksSinceEpoch % n
	week := weeksSinceEpoch + (n - remainder)
	if remainder == 0 {
		return now, nil
	}

	// Loop until we find a week that doesn't fail. This should never loop, but
	// we account for failures just in case.
	var lastErr error
	for i := int64(0); i < 3; i++ {
		monday, err := GetMondayOfWeek(now.Location(), week+i)
		if err != nil {
			lastErr = err
			continue
		}

		return monday, nil
	}

	return time.Time{}, xerrors.Errorf("get next applicable Monday of %v weeks: %w", n, lastErr)
}