Improvements to iCalendar support for SMF's calendar

Sources/Actions/Calendar.php

@@ -24,6 +24,7 @@
 use SMF\Calendar\Event;
 use SMF\Calendar\EventOccurrence;
 use SMF\Calendar\Holiday;
+use SMF\Calendar\VTimeZone;
 use SMF\Config;
 use SMF\Db\DatabaseApi as Db;
 use SMF\ErrorHandler;
@@ -626,8 +627,10 @@ public function export(): void
 				&& ($occurrence = $event->getOccurrence($_REQUEST['recurrenceid'])) !== false
 			) {
 				$file['content'][] = $occurrence->export();
+				$file['content'][] = VTimeZone::load($occurrence->tzid)->export($occurrence->start, $occurrence->end);
 			} else {
 				$file['content'][] = $event->export();
+				$file['content'][] = VTimeZone::load($event->tzid)->export($event->start, $event->end);
 			}
 
 			$file['filename'] = $event->title . '.ics';
@@ -656,6 +659,7 @@ public function export(): void
 			$high_date = (clone $low_date)->add($duration);
 
 			$full_event_uids = [];
+			$tzids = [];
 
 			foreach (Event::getOccurrencesInRange($low_date->format('Y-m-d'), $high_date->format('Y-m-d'), true) as $occurrence) {
 				$event = $occurrence->getParentEvent();
@@ -674,17 +678,41 @@ public function export(): void
 						&& $event->getRecurrenceEnd() <= $high_date
 					)
 				) {
+					if (!isset($tzids[$event->tzid])) {
+						$tzids[$event->tzid] = [
+							'min' => $event->start,
+							'max' => $event->end,
+						];
+					}
+
+					$tzids[$event->tzid]['min'] = $tzids[$event->tzid]['min'] > $event->start ? $event->start : $tzids[$event->tzid]['min'];
+					$tzids[$event->tzid]['max'] = $tzids[$event->tzid]['max'] < $event->end ? $event->end : $tzids[$event->tzid]['max'];
+
 					$file['content'][] = $event->export();
 					$full_event_ids[] = $event->uid;
 				}
 				// Otherwise, export just this occurrence.
 				else {
+					if (!isset($tzids[$occurrence->tzid])) {
+						$tzids[$occurrence->tzid] = [
+							'min' => $occurrence->start,
+							'max' => $occurrence->end,
+						];
+					}
+
+					$tzids[$occurrence->tzid]['min'] = $tzids[$occurrence->tzid]['min'] > $occurrence->start ? $occurrence->start : $tzids[$occurrence->tzid]['min'];
+					$tzids[$occurrence->tzid]['max'] = $tzids[$occurrence->tzid]['max'] < $occurrence->end ? $occurrence->end : $tzids[$occurrence->tzid]['max'];
+
 					$file['content'][] = $occurrence->export();
 				}
 
 				$file['mtime'] = max($file['mtime'], $event->modified_time);
 			}
 
+			foreach ($tzids as $tzid => $range) {
+				$file['content'][] = VTimeZone::load($tzid)->export($range['min'], $range['max']);
+			}
+
 			$file['filename'] = implode(' ', [Utils::$context['forum_name'], Lang::$txt['events'], $low_date->format('Y-m-d'), $high_date->format('Y-m-d')]) . '.ics';
 		}
 

Sources/Calendar/Event.php

@@ -834,6 +834,15 @@ public function export(): string
 			$filecontents[] = 'EXDATE' . ($this->allday ? ';VALUE=DATE' : '') . ':' . implode(",\r\n ", $this->recurrence_iterator->getExDates());
 		}
 
+		if ($this instanceof Holiday) {
+			$filecontents[] = 'CATEGORIES:Holidays';
+			$filecontents[] = 'TRANSP:TRANSPARENT';
+		} elseif ($this instanceof Birthday) {
+			$filecontents[] = 'TRANSP:TRANSPARENT';
+		} else {
+			$filecontents[] = 'TRANSP:OPAQUE';
+		}
+
 		$filecontents[] = 'END:VEVENT';
 
 		// Fit all lines within iCalendar's line width restraint.

Sources/Calendar/EventOccurrence.php

@@ -217,6 +217,15 @@ public function export(): string
 		$filecontents[] = 'DTSTART' . ($this->allday ? ';VALUE=DATE' : (!in_array($this->tz, RRule::UTC_SYNONYMS) ? ';TZID=' . $this->tz : '')) . ':' . $this->start->format('Ymd' . ($this->allday ? '' : '\\THis' . (in_array($this->tz, RRule::UTC_SYNONYMS) ? '\\Z' : '')));
 		$filecontents[] = 'DURATION:' . (string) $this->duration;
 
+		if ($this->getParentEvent() instanceof Holiday) {
+			$filecontents[] = 'CATEGORIES:Holidays';
+			$filecontents[] = 'TRANSP:TRANSPARENT';
+		} elseif ($this->getParentEvent() instanceof Birthday) {
+			$filecontents[] = 'TRANSP:TRANSPARENT';
+		} else {
+			$filecontents[] = 'TRANSP:OPAQUE';
+		}
+
 		$filecontents[] = 'END:VEVENT';
 
 		foreach ($filecontents as $line_num => $line) {

Sources/Calendar/RecurrenceIterator.php

@@ -1255,7 +1255,7 @@ private function expand(\DateTime $current, ?string $break_after = null): \Gener
 
 						foreach ($this->rrule->{$prop} as $value) {
 							if ($value != $current_value) {
-								$temp = \DateTime::createFromFormat('Y z H:i:s e', $temp->format('Y ') . ($value - 1) . $temp->format(' H:i:s e'));
+								$temp = \DateTime::createFromFormat('Y z H:i:s e', $temp->format('Y ') . ($value > 0 ? $value - 1 : $value + ((bool) $temp->format('L') && $value >= -306 ? 366 : 365)) . $temp->format(' H:i:s e'));
 
 								yield $temp;