public function applyInternalEffects($object, $value)
{
$rrule = id(new PhutilCalendarRecurrenceRule())->setFrequency($value);
// If the user creates a monthly event on the 29th, 30th or 31st of a
// month, it means "the 30th of every month" as far as the RRULE is
// concerned. Such an event will not occur on months with fewer days.
// This is surprising, and proably not what the user wants. Instead,
// schedule these events relative to the end of the month: on the "-1st",
// "-2nd" or "-3rd" day of the month. For example, a monthly event on
// the 31st of a 31-day month translates to "every month, on the last
// day of the month".
if ($value == PhutilCalendarRecurrenceRule::FREQUENCY_MONTHLY) {
$start_datetime = $object->newStartDateTime();
$y = $start_datetime->getYear();
$m = $start_datetime->getMonth();
$d = $start_datetime->getDay();
if ($d >= 29) {
$year_map = PhutilCalendarRecurrenceRule::getYearMap($y, PhutilCalendarRecurrenceRule::WEEKDAY_MONDAY);
$month_days = $year_map['monthDays'][$m];
$schedule_on = -($month_days + 1 - $d);
$rrule->setByMonthDay(array($schedule_on));
}
}
$object->setRecurrenceRule($rrule);
}
