/**
* If the event is recurring, this function calculates the best
* possible end date to use for the series. It will attempt to calculate
* an end date from the RRULE if possible, and will fall back to the PHP
* max date otherwise. The generateInstances function will still limit
* the results regardless. For non-recurring events, it simply returns
* the existing end date value as-is.
*/
function calculateEndDate($event)
{
global $date_format, $mappings;
$end = $event[$mappings['end_date']];
$rrule = $event[$mappings['rrule']];
$isRecurring = isset($rrule) && $rrule !== '';
if ($isRecurring) {
$max_date = new DateTime('9999-12-31');
$recurrence = new When();
$recurrence->rrule($rrule);
if (isset($recurrence->end_date) && $recurrence->end_date < $max_date) {
// The RRULE includes an explicit end date, so use that
$end = $recurrence->end_date->format($date_format) . 'Z';
} else {
if (isset($recurrence->count) && $recurrence->count > 0) {
// The RRULE has a limit, so calculate the end date based on the instance count
$count = 0;
$newEnd;
$rdates = $recurrence->recur($event[$mappings['start_date']])->rrule($rrule);
while ($rdate = $rdates->next()) {
$newEnd = $rdate;
if (++$count > $recurrence->count) {
break;
}
}
// The 'minutes' portion should match Extensible.calendar.data.EventModel.resolution:
$newEnd->modify('+' . $event[$mappings['duration']] . ' minutes');
$end = $newEnd->format($date_format) . 'Z';
} else {
// The RRULE does not specify an end date or count, so default to max date
$end = date($date_format, PHP_INT_MAX) . 'Z';
}
}
}
return $end;
}
/**
* If the event is recurring, returns the maximum end date
* supported by PHP so that the event will fall within future
* query ranges as possibly having matching instances. Note
* that in a real implementation it would be better to calculate
* the actual recurrence pattern end date if possible. The current
* recurrence class used in this example does not make it convenient
* to do that, so for demo purposes we'll just use the PHP max date.
* The generateInstances() method will still limit results based on
* any end date specified, so it will work as expected -- it simply
* means that in a real-world implementation querying might be slightly
* less efficient (which does not apply in this example).
*/
private static function calculateEndDate($attr)
{
$end = $attr[Event::$end_date];
if (isset($attr[Event::$rrule]) && $attr[Event::$rrule] != '') {
$max_date = new DateTime('9999-12-31');
$recurrence = new When();
$recurrence->rrule($attr[Event::$rrule]);
if (isset($recurrence->end_date) && $recurrence->end_date < $max_date) {
$end = $recurrence->end_date->format($_SESSION['dtformat']) . 'Z';
} else {
if (isset($recurrence->count) && $recurrence->count > 0) {
$count = 0;
$newEnd;
$rdates = $recurrence->recur($attr[Event::$start_date])->rrule($attr[Event::$rrule]);
while ($rdate = $rdates->next()) {
$newEnd = $rdate;
if (++$count > $recurrence->count) {
break;
}
}
// The 'minutes' portion should match Extensible.calendar.data.EventModel.resolution:
$newEnd->modify('+' . $attr[Event::$duration] . ' minutes');
$end = $newEnd->format($_SESSION['dtformat']) . 'Z';
} else {
// default to max date if nothing else
$end = date($_SESSION['dtformat'], PHP_INT_MAX) . 'Z';
}
}
}
return $end;
}
