internal static TimerSchedule Create()

in src/WebJobs.Extensions/Extensions/Timers/Scheduling/TimerSchedule.cs [61:99]
35 lines of code
8 McCabe index (conditional complexity)

        internal static TimerSchedule Create(TimerTriggerAttribute attribute, INameResolver nameResolver, ILogger logger)
        {
            TimerSchedule schedule = null;

            if (!string.IsNullOrEmpty(attribute.ScheduleExpression))
            {
                string resolvedExpression = nameResolver.ResolveWholeString(attribute.ScheduleExpression);
                if (CronSchedule.TryCreate(resolvedExpression, logger, out CronSchedule cronSchedule))
                {
                    schedule = cronSchedule;
                    if (attribute.UseMonitor && ShouldDisableScheduleMonitor(cronSchedule, DateTime.Now))
                    {
                        logger.LogDebug("UseMonitor changed to false based on schedule frequency.");
                        attribute.UseMonitor = false;
                    }
                }
                else if (TimeSpan.TryParse(resolvedExpression, out TimeSpan periodTimespan))
                {
                    schedule = new ConstantSchedule(periodTimespan);

                    if (attribute.UseMonitor && periodTimespan.TotalMinutes < 1)
                    {
                        // for very frequent constant schedules, we want to disable persistence
                        logger.LogDebug("UseMonitor changed to false based on schedule frequency.");
                        attribute.UseMonitor = false;
                    }
                }
                else
                {
                    throw new ArgumentException(string.Format("The schedule expression '{0}' was not recognized as a valid cron expression or timespan string.", resolvedExpression));
                }
            }
            else
            {
                schedule = (TimerSchedule)Activator.CreateInstance(attribute.ScheduleType);
            }

            return schedule;
        }