OCA\DAV\CalDAV\Schedule\Plugin

Complexity

Total Complexity

77

Size/Duplication

Total Lines	573
Duplicated Lines	0 %

Importance

Changes

0

18 Methods

Rating	Name	Duplication	Size	Complexity
A	getDTEndFromVEvent()	0	26	4
A	initialize()	0	5	1
A	getAttendeeRSVP()	0	9	4
A	dispatchSchedulingResponses()	0	7	3
C	isAvailableAtTime()	0	128	10
A	isCalendarDeleted()	0	3	2
C	scheduleLocalDelivery()	0	109	15
A	getCurrentAttendee()	0	11	3
A	createCalendar()	0	3	1
A	__construct()	0	3	1
A	getCalendar()	0	2	1
A	getCalendarUserTypeForPrincipal()	0	13	2
D	propFindDefaultCalendarUrl()	0	80	19
A	calendarObjectChange()	0	7	2
A	propFind()	0	17	4
A	stripOffMailTo()	0	6	2
A	getAddressesForPrincipal()	0	8	2
A	setPathOfCalendarObjectChange()	0	2	1

<?php
/**
 * @copyright Copyright (c) 2016, Roeland Jago Douma <roeland@famdouma.nl>
 * @copyright Copyright (c) 2016, Joas Schilling <coding@schilljs.com>
 *
 * @author Christoph Wurst <christoph@winzerhof-wurst.at>
 * @author Daniel Kesselberg <mail@danielkesselberg.de>
 * @author Georg Ehrke <oc.list@georgehrke.com>
 * @author Joas Schilling <coding@schilljs.com>
 * @author Roeland Jago Douma <roeland@famdouma.nl>
 * @author Thomas Citharel <nextcloud@tcit.fr>
 * @author Richard Steinmetz <richard@steinmetz.cloud>
 *
 * @license GNU AGPL version 3 or any later version
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 *
 */
namespace OCA\DAV\CalDAV\Schedule;

use DateTimeZone;
use OCA\DAV\CalDAV\CalDavBackend;
use OCA\DAV\CalDAV\Calendar;
use OCA\DAV\CalDAV\CalendarHome;
use OCP\IConfig;
use Psr\Log\LoggerInterface;
use Sabre\CalDAV\ICalendar;
use Sabre\DAV\INode;
use Sabre\DAV\IProperties;
use Sabre\DAV\PropFind;
use Sabre\DAV\Server;
use Sabre\DAV\Xml\Property\LocalHref;
use Sabre\DAVACL\IPrincipal;
use Sabre\HTTP\RequestInterface;
use Sabre\HTTP\ResponseInterface;
use Sabre\VObject\Component;
use Sabre\VObject\Component\VCalendar;
use Sabre\VObject\Component\VEvent;
use Sabre\VObject\DateTimeParser;
use Sabre\VObject\FreeBusyGenerator;
use Sabre\VObject\ITip;
use Sabre\VObject\Parameter;
use Sabre\VObject\Property;
use Sabre\VObject\Reader;
use function \Sabre\Uri\split;

The function \Sabre\Uri\split was not found. Maybe you did not declare it correctly or list all dependencies?

class Plugin extends \Sabre\CalDAV\Schedule\Plugin {

	/**
	 * @var IConfig
	 */
	private $config;

	/** @var ITip\Message[] */
	private $schedulingResponses = [];

	/** @var string|null */
	private $pathOfCalendarObjectChange = null;

	public const CALENDAR_USER_TYPE = '{' . self::NS_CALDAV . '}calendar-user-type';
	public const SCHEDULE_DEFAULT_CALENDAR_URL = '{' . Plugin::NS_CALDAV . '}schedule-default-calendar-URL';
	private LoggerInterface $logger;

	/**
	 * @param IConfig $config
	 */
	public function __construct(IConfig $config, LoggerInterface $logger) {
		$this->config = $config;
		$this->logger = $logger;
	}

	/**
	 * Initializes the plugin
	 *
	 * @param Server $server
	 * @return void
	 */
	public function initialize(Server $server) {
		parent::initialize($server);
		$server->on('propFind', [$this, 'propFindDefaultCalendarUrl'], 90);
		$server->on('afterWriteContent', [$this, 'dispatchSchedulingResponses']);
		$server->on('afterCreateFile', [$this, 'dispatchSchedulingResponses']);
	}

	/**
	 * Allow manual setting of the object change URL
	 * to support public write
	 *
	 * @param string $path
	 */
	public function setPathOfCalendarObjectChange(string $path): void {
		$this->pathOfCalendarObjectChange = $path;
	}

	/**
	 * This method handler is invoked during fetching of properties.
	 *
	 * We use this event to add calendar-auto-schedule-specific properties.
	 *
	 * @param PropFind $propFind
	 * @param INode $node
	 * @return void
	 */
	public function propFind(PropFind $propFind, INode $node) {
		if ($node instanceof IPrincipal) {
			// overwrite Sabre/Dav's implementation
			$propFind->handle(self::CALENDAR_USER_TYPE, function () use ($node) {
				if ($node instanceof IProperties) {
					$props = $node->getProperties([self::CALENDAR_USER_TYPE]);

					if (isset($props[self::CALENDAR_USER_TYPE])) {
						return $props[self::CALENDAR_USER_TYPE];
					}
				}

				return 'INDIVIDUAL';
			});
		}

		parent::propFind($propFind, $node);
	}

	/**
	 * Returns a list of addresses that are associated with a principal.
	 *
	 * @param string $principal
	 * @return array
	 */
	protected function getAddressesForPrincipal($principal) {
		$result = parent::getAddressesForPrincipal($principal);

		if ($result === null) {

The condition $result === null is always false.

			$result = [];
		}

		return $result;
	}

	/**
	 * @param RequestInterface $request
	 * @param ResponseInterface $response
	 * @param VCalendar $vCal
	 * @param mixed $calendarPath
	 * @param mixed $modified
	 * @param mixed $isNew
	 */
	public function calendarObjectChange(RequestInterface $request, ResponseInterface $response, VCalendar $vCal, $calendarPath, &$modified, $isNew) {
		// Save the first path we get as a calendar-object-change request
		if (!$this->pathOfCalendarObjectChange) {
			$this->pathOfCalendarObjectChange = $request->getPath();
		}

		parent::calendarObjectChange($request, $response, $vCal, $calendarPath, $modified, $isNew);
	}

	/**
	 * @inheritDoc
	 */
	public function scheduleLocalDelivery(ITip\Message $iTipMessage):void {
		/** @var VEvent|null $vevent */
		$vevent = $iTipMessage->message->VEVENT ?? null;

		// Strip VALARMs from incoming VEVENT
		if ($vevent && isset($vevent->VALARM)) {
			$vevent->remove('VALARM');
		}

		parent::scheduleLocalDelivery($iTipMessage);
		// We only care when the message was successfully delivered locally
		// Log all possible codes returned from the parent method that mean something went wrong
		// 3.7, 3.8, 5.0, 5.2
		if ($iTipMessage->scheduleStatus !== '1.2;Message delivered locally') {
			$this->logger->debug('Message not delivered locally with status: ' . $iTipMessage->scheduleStatus);
			return;
		}
		// We only care about request. reply and cancel are properly handled
		// by parent::scheduleLocalDelivery already
		if (strcasecmp($iTipMessage->method, 'REQUEST') !== 0) {
			return;
		}

		// If parent::scheduleLocalDelivery set scheduleStatus to 1.2,
		// it means that it was successfully delivered locally.
		// Meaning that the ACL plugin is loaded and that a principal
		// exists for the given recipient id, no need to double check
		/** @var \Sabre\DAVACL\Plugin $aclPlugin */
		$aclPlugin = $this->server->getPlugin('acl');
		$principalUri = $aclPlugin->getPrincipalByUri($iTipMessage->recipient);
		$calendarUserType = $this->getCalendarUserTypeForPrincipal($principalUri);
		if (strcasecmp($calendarUserType, 'ROOM') !== 0 && strcasecmp($calendarUserType, 'RESOURCE') !== 0) {
			$this->logger->debug('Calendar user type is room or resource, not processing further');
			return;
		}

		$attendee = $this->getCurrentAttendee($iTipMessage);
		if (!$attendee) {
			$this->logger->debug('No attendee set for scheduling message');
			return;
		}

		// We only respond when a response was actually requested
		$rsvp = $this->getAttendeeRSVP($attendee);
		if (!$rsvp) {
			$this->logger->debug('No RSVP requested for attendee ' . $attendee->getValue());
			return;
		}

		if (!$vevent) {
			$this->logger->debug('No VEVENT set to process on scheduling message');
			return;
		}

		// We don't support autoresponses for recurrencing events for now
		if (isset($vevent->RRULE) || isset($vevent->RDATE)) {
			$this->logger->debug('VEVENT is a recurring event, autoresponding not supported');
			return;
		}

		$dtstart = $vevent->DTSTART;
		$dtend = $this->getDTEndFromVEvent($vevent);
		$uid = $vevent->UID->getValue();

The method getValue() does not exist on null.

		$sequence = isset($vevent->SEQUENCE) ? $vevent->SEQUENCE->getValue() : 0;

The method getValue() does not exist on null.

		$recurrenceId = isset($vevent->{'RECURRENCE-ID'}) ? $vevent->{'RECURRENCE-ID'}->serialize() : '';

		$message = <<<EOF
BEGIN:VCALENDAR
PRODID:-//Nextcloud/Nextcloud CalDAV Server//EN
METHOD:REPLY
VERSION:2.0
BEGIN:VEVENT
ATTENDEE;PARTSTAT=%s:%s
ORGANIZER:%s
UID:%s
SEQUENCE:%s
REQUEST-STATUS:2.0;Success
%sEND:VEVENT
END:VCALENDAR
EOF;

		if ($this->isAvailableAtTime($attendee->getValue(), $dtstart->getDateTime(), $dtend->getDateTime(), $uid)) {

The method getDateTime() does not exist on null.

The method getDateTime() does not exist on Sabre\VObject\Property. It seems like you code against a sub-type of Sabre\VObject\Property such as Sabre\VObject\Property\ICalendar\DateTime or Sabre\VObject\Property\VCard\DateAndOrTime.

			$partStat = 'ACCEPTED';
		} else {
			$partStat = 'DECLINED';
		}

		$vObject = Reader::read(vsprintf($message, [
			$partStat,
			$iTipMessage->recipient,
			$iTipMessage->sender,
			$uid,
			$sequence,
			$recurrenceId
		]));

		$responseITipMessage = new ITip\Message();
		$responseITipMessage->uid = $uid;
		$responseITipMessage->component = 'VEVENT';
		$responseITipMessage->method = 'REPLY';
		$responseITipMessage->sequence = $sequence;

It seems like $sequence can also be of type string. However, the property $sequence is declared as type integer. Maybe add an additional type check?

		$responseITipMessage->sender = $iTipMessage->recipient;
		$responseITipMessage->recipient = $iTipMessage->sender;
		$responseITipMessage->message = $vObject;

		// We can't dispatch them now already, because the organizers calendar-object
		// was not yet created. Hence Sabre/DAV won't find a calendar-object, when we
		// send our reply.
		$this->schedulingResponses[] = $responseITipMessage;
	}

	/**
	 * @param string $uri
	 */
	public function dispatchSchedulingResponses(string $uri):void {
		if ($uri !== $this->pathOfCalendarObjectChange) {
			return;
		}

		foreach ($this->schedulingResponses as $schedulingResponse) {
			$this->scheduleLocalDelivery($schedulingResponse);
		}
	}

	/**
	 * Always use the personal calendar as target for scheduled events
	 *
	 * @param PropFind $propFind
	 * @param INode $node
	 * @return void
	 */
	public function propFindDefaultCalendarUrl(PropFind $propFind, INode $node) {
		if ($node instanceof IPrincipal) {
			$propFind->handle(self::SCHEDULE_DEFAULT_CALENDAR_URL, function () use ($node) {
				/** @var \OCA\DAV\CalDAV\Plugin $caldavPlugin */
				$caldavPlugin = $this->server->getPlugin('caldav');
				$principalUrl = $node->getPrincipalUrl();

				$calendarHomePath = $caldavPlugin->getCalendarHomeForPrincipal($principalUrl);
				if (!$calendarHomePath) {
					return null;
				}

				$isResourceOrRoom = strpos($principalUrl, 'principals/calendar-resources') === 0 ||
					strpos($principalUrl, 'principals/calendar-rooms') === 0;

				if (strpos($principalUrl, 'principals/users') === 0) {
					[, $userId] = split($principalUrl);

The call to split() has too few arguments starting with string.

					$uri = $this->config->getUserValue($userId, 'dav', 'defaultCalendar', CalDavBackend::PERSONAL_CALENDAR_URI);
					$displayName = CalDavBackend::PERSONAL_CALENDAR_NAME;
				} elseif ($isResourceOrRoom) {
					$uri = CalDavBackend::RESOURCE_BOOKING_CALENDAR_URI;
					$displayName = CalDavBackend::RESOURCE_BOOKING_CALENDAR_NAME;
				} else {
					// How did we end up here?
					// TODO - throw exception or just ignore?
					return null;
				}

				/** @var CalendarHome $calendarHome */
				$calendarHome = $this->server->tree->getNodeForPath($calendarHomePath);
				$currentCalendarDeleted = false;
				if (!$calendarHome->childExists($uri) || $currentCalendarDeleted = $this->isCalendarDeleted($calendarHome, $uri)) {
					// If the default calendar doesn't exist
					if ($isResourceOrRoom) {
						// Resources or rooms can't be in the trashbin, so we're fine
						$this->createCalendar($calendarHome, $principalUrl, $uri, $displayName);
					} else {
						// And we're not handling scheduling on resource/room booking
						$userCalendars = [];
						/**
						 * If the default calendar of the user isn't set and the
						 * fallback doesn't match any of the user's calendar
						 * try to find the first "personal" calendar we can write to
						 * instead of creating a new one.
						 * A appropriate personal calendar to receive invites:
						 * - isn't a calendar subscription
						 * - user can write to it (no virtual/3rd-party calendars)
						 * - calendar isn't a share
						 */
						foreach ($calendarHome->getChildren() as $node) {
							if ($node instanceof Calendar && !$node->isSubscription() && $node->canWrite() && !$node->isShared() && !$node->isDeleted()) {
								$userCalendars[] = $node;
							}
						}

						if (count($userCalendars) > 0) {
							// Calendar backend returns calendar by calendarorder property
							$uri = $userCalendars[0]->getName();
						} else {
							// Otherwise if we have really nothing, create a new calendar
							if ($currentCalendarDeleted) {
								// If the calendar exists but is deleted, we need to purge it first
								// This may cause some issues in a non synchronous database setup
								$calendar = $this->getCalendar($calendarHome, $uri);
								if ($calendar instanceof Calendar) {
									$calendar->disableTrashbin();
									$calendar->delete();
								}
							}
							$this->createCalendar($calendarHome, $principalUrl, $uri, $displayName);
						}
					}
				}

				$result = $this->server->getPropertiesForPath($calendarHomePath . '/' . $uri, [], 1);
				if (empty($result)) {
					return null;
				}

				return new LocalHref($result[0]['href']);
			});
		}
	}

	/**
	 * Returns a list of addresses that are associated with a principal.
	 *
	 * @param string $principal
	 * @return string|null
	 */
	protected function getCalendarUserTypeForPrincipal($principal):?string {
		$calendarUserType = '{' . self::NS_CALDAV . '}calendar-user-type';
		$properties = $this->server->getProperties(
			$principal,
			[$calendarUserType]
		);

		// If we can't find this information, we'll stop processing
		if (!isset($properties[$calendarUserType])) {
			return null;
		}

		return $properties[$calendarUserType];
	}

	/**
	 * @param ITip\Message $iTipMessage
	 * @return null|Property
	 */
	private function getCurrentAttendee(ITip\Message $iTipMessage):?Property {
		/** @var VEvent $vevent */
		$vevent = $iTipMessage->message->VEVENT;
		$attendees = $vevent->select('ATTENDEE');
		foreach ($attendees as $attendee) {
			/** @var Property $attendee */
			if (strcasecmp($attendee->getValue(), $iTipMessage->recipient) === 0) {
				return $attendee;
			}
		}
		return null;
	}

	/**
	 * @param Property|null $attendee
	 * @return bool
	 */
	private function getAttendeeRSVP(Property $attendee = null):bool {
		if ($attendee !== null) {
			$rsvp = $attendee->offsetGet('RSVP');
			if (($rsvp instanceof Parameter) && (strcasecmp($rsvp->getValue(), 'TRUE') === 0)) {
				return true;
			}
		}
		// RFC 5545 3.2.17: default RSVP is false
		return false;
	}

	/**
	 * @param VEvent $vevent
	 * @return Property\ICalendar\DateTime
	 */
	private function getDTEndFromVEvent(VEvent $vevent):Property\ICalendar\DateTime {
		if (isset($vevent->DTEND)) {
			return $vevent->DTEND;

The expression return $vevent->DTEND returns the type null which is incompatible with the type-hinted return Sabre\VObject\Property\ICalendar\DateTime.

		}

		if (isset($vevent->DURATION)) {
			$isFloating = $vevent->DTSTART->isFloating();

The method isFloating() does not exist on null.

The method isFloating() does not exist on Sabre\VObject\Property. It seems like you code against a sub-type of Sabre\VObject\Property such as Sabre\VObject\Property\ICalendar\DateTime.

			/** @var Property\ICalendar\DateTime $end */
			$end = clone $vevent->DTSTART;
			$endDateTime = $end->getDateTime();
			$endDateTime = $endDateTime->add(DateTimeParser::parse($vevent->DURATION->getValue()));

The method getValue() does not exist on null.

			$end->setDateTime($endDateTime, $isFloating);
			return $end;
		}

		if (!$vevent->DTSTART->hasTime()) {

The method hasTime() does not exist on Sabre\VObject\Property. It seems like you code against a sub-type of Sabre\VObject\Property such as Sabre\VObject\Property\ICalendar\DateTime.

			$isFloating = $vevent->DTSTART->isFloating();
			/** @var Property\ICalendar\DateTime $end */
			$end = clone $vevent->DTSTART;
			$endDateTime = $end->getDateTime();
			$endDateTime = $endDateTime->modify('+1 day');
			$end->setDateTime($endDateTime, $isFloating);
			return $end;
		}

		return clone $vevent->DTSTART;

The expression return clone $vevent->DTSTART returns the type Sabre\VObject\Property which includes types incompatible with the type-hinted return Sabre\VObject\Property\ICalendar\DateTime.

	}

	/**
	 * @param string $email
	 * @param \DateTimeInterface $start
	 * @param \DateTimeInterface $end
	 * @param string $ignoreUID
	 * @return bool
	 */
	private function isAvailableAtTime(string $email, \DateTimeInterface $start, \DateTimeInterface $end, string $ignoreUID):bool {
		// This method is heavily inspired by Sabre\CalDAV\Schedule\Plugin::scheduleLocalDelivery
		// and Sabre\CalDAV\Schedule\Plugin::getFreeBusyForEmail

		$aclPlugin = $this->server->getPlugin('acl');
		$this->server->removeListener('propFind', [$aclPlugin, 'propFind']);

		$result = $aclPlugin->principalSearch(

The method principalSearch() does not exist on Sabre\DAV\ServerPlugin. It seems like you code against a sub-type of Sabre\DAV\ServerPlugin such as Sabre\DAVACL\Plugin.

			['{http://sabredav.org/ns}email-address' => $this->stripOffMailTo($email)],
			[
				'{DAV:}principal-URL',
				'{' . self::NS_CALDAV . '}calendar-home-set',
				'{' . self::NS_CALDAV . '}schedule-inbox-URL',
				'{http://sabredav.org/ns}email-address',

			]
		);
		$this->server->on('propFind', [$aclPlugin, 'propFind'], 20);


		// Grabbing the calendar list
		$objects = [];
		$calendarTimeZone = new DateTimeZone('UTC');

		$homePath = $result[0][200]['{' . self::NS_CALDAV . '}calendar-home-set']->getHref();
		foreach ($this->server->tree->getNodeForPath($homePath)->getChildren() as $node) {

The method getChildren() does not exist on Sabre\DAV\INode. It seems like you code against a sub-type of Sabre\DAV\INode such as Sabre\DAV\ICollection or Sabre\DAV\Collection or Sabre\CalDAV\Principal\User or OCA\DAV\CardDAV\Integration\ExternalAddressBook or OCA\DAV\CalDAV\Trashbin\TrashbinHome or Sabre\CalDAV\Calendar or OCA\DAV\Comments\EntityCollection or Sabre\CardDAV\AddressBook or OCA\DAV\CalDAV\Integration\ExternalCalendar or Sabre\CalDAV\Subscriptions\ISubscription or Sabre\CalDAV\Principal\User or Sabre\CalDAV\SharedCalendar or OCA\DAV\Connector\Sabre\Directory or Sabre\CardDAV\AddressBookHome or Sabre\CalDAV\CalendarHome or Sabre\DAVACL\FS\HomeCollection or OCA\DAV\CalDAV\Trashbin\TrashbinHome or Sabre\CalDAV\ICalendar or Sabre\CalDAV\Schedule\IInbox or Sabre\DAVACL\PrincipalCollection or Sabre\CalDAV\Subscriptions\Subscription or OCA\ContactsInteraction\AddressBook or Sabre\CalDAV\Schedule\IOutbox or Sabre\CalDAV\Notifications\Collection or Sabre\DAVACL\FS\Collection or Sabre\CardDAV\AddressBook or Sabre\CalDAV\Principal\User or Sabre\CalDAV\Principal\User or OCA\DAV\CalDAV\Calendar or OCA\DAV\CardDAV\AddressBook or Sabre\DAV\FSExt\Directory or Sabre\DAV\FS\Directory.

			if (!$node instanceof ICalendar) {
				continue;
			}

			// Getting the list of object uris within the time-range
			$urls = $node->calendarQuery([
				'name' => 'VCALENDAR',
				'comp-filters' => [
					[
						'name' => 'VEVENT',
						'is-not-defined' => false,
						'time-range' => [
							'start' => $start,
							'end' => $end,
						],
						'comp-filters' => [],
						'prop-filters' => [],
					],
					[
						'name' => 'VEVENT',
						'is-not-defined' => false,
						'time-range' => null,
						'comp-filters' => [],
						'prop-filters' => [
							[
								'name' => 'UID',
								'is-not-defined' => false,
								'time-range' => null,
								'text-match' => [
									'value' => $ignoreUID,
									'negate-condition' => true,
									'collation' => 'i;octet',
								],
								'param-filters' => [],
							],
						]
					],
				],
				'prop-filters' => [],
				'is-not-defined' => false,
				'time-range' => null,
			]);

			foreach ($urls as $url) {
				$objects[] = $node->getChild($url)->get();

The method get() does not exist on Sabre\DAV\INode. It seems like you code against a sub-type of Sabre\DAV\INode such as Sabre\DAV\IFile or Sabre\DAV\File or OCA\DAV\Connector\Sabre\File or OCA\ContactsInteraction\Card or Sabre\DAVACL\FS\File or Sabre\CardDAV\Card or Sabre\CalDAV\CalendarObject or Sabre\CalDAV\Notifications\Node or OCA\DAV\CalDAV\Trashbin\DeletedCalendarObject or Sabre\DAV\FSExt\File or Sabre\DAV\FS\File.

			}
		}

		$inboxProps = $this->server->getProperties(
			$result[0][200]['{' . self::NS_CALDAV . '}schedule-inbox-URL']->getHref(),
			['{' . self::NS_CALDAV . '}calendar-availability']
		);

		$vcalendar = new VCalendar();
		$vcalendar->METHOD = 'REPLY';

		$generator = new FreeBusyGenerator();
		$generator->setObjects($objects);
		$generator->setTimeRange($start, $end);
		$generator->setBaseObject($vcalendar);
		$generator->setTimeZone($calendarTimeZone);

		if (isset($inboxProps['{' . self::NS_CALDAV . '}calendar-availability'])) {
			$generator->setVAvailability(
				Reader::read(
					$inboxProps['{' . self::NS_CALDAV . '}calendar-availability']
				)
			);
		}

		$result = $generator->getResult();
		if (!isset($result->VFREEBUSY)) {
			return false;
		}

		/** @var Component $freeBusyComponent */
		$freeBusyComponent = $result->VFREEBUSY;
		$freeBusyProperties = $freeBusyComponent->select('FREEBUSY');
		// If there is no Free-busy property at all, the time-range is empty and available
		if (count($freeBusyProperties) === 0) {
			return true;
		}

		// If more than one Free-Busy property was returned, it means that an event
		// starts or ends inside this time-range, so it's not available and we return false
		if (count($freeBusyProperties) > 1) {
			return false;
		}

		/** @var Property $freeBusyProperty */
		$freeBusyProperty = $freeBusyProperties[0];
		if (!$freeBusyProperty->offsetExists('FBTYPE')) {
			// If there is no FBTYPE, it means it's busy
			return false;
		}

		$fbTypeParameter = $freeBusyProperty->offsetGet('FBTYPE');
		if (!($fbTypeParameter instanceof Parameter)) {
			return false;
		}

		return (strcasecmp($fbTypeParameter->getValue(), 'FREE') === 0);
	}

	/**
	 * @param string $email
	 * @return string
	 */
	private function stripOffMailTo(string $email): string {
		if (stripos($email, 'mailto:') === 0) {
			return substr($email, 7);
		}

		return $email;
	}

	private function getCalendar(CalendarHome $calendarHome, string $uri): INode {
		return $calendarHome->getChild($uri);
	}

	private function isCalendarDeleted(CalendarHome $calendarHome, string $uri): bool {
		$calendar = $this->getCalendar($calendarHome, $uri);
		return $calendar instanceof Calendar && $calendar->isDeleted();
	}

	private function createCalendar(CalendarHome $calendarHome, string $principalUri, string $uri, string $displayName): void {
		$calendarHome->getCalDAVBackend()->createCalendar($principalUri, $uri, [
			'{DAV:}displayname' => $displayName,
		]);
	}
}