diff --git a/appinfo/info.xml b/appinfo/info.xml
index 71fadf8cf..bb0096647 100644
--- a/appinfo/info.xml
+++ b/appinfo/info.xml
@@ -47,6 +47,10 @@
 	<background-jobs>
 		<job>OCA\Calendar\BackgroundJob\CleanUpOutdatedBookingsJob</job>
 	</background-jobs>
+	<commands>
+		<command>OCA\Calendar\Command\Import</command>
+		<command>OCA\Calendar\Command\Export</command>
+	</commands>
 	<navigations>
 		<navigation>
 			<id>calendar</id>
diff --git a/lib/Command/Export.php b/lib/Command/Export.php
new file mode 100644
index 000000000..7c77e961b
--- /dev/null
+++ b/lib/Command/Export.php
@@ -0,0 +1,161 @@
+<?php
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\Calendar\Command;
+
+use OCA\Calendar\Service\Export\ExportService;
+use OCP\Calendar\ICalendarExport;
+use OCP\Calendar\IManager;
+use OCP\IUserManager;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class Export extends Command {
+	public function __construct(
+		private IUserManager $userManager,
+		private IManager $calendarManager,
+		private ExportService $exportService,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		$this->setName('calendar:export')
+			 ->setDescription('Export a specific calendar for a user')
+			 ->addArgument('uid', InputArgument::REQUIRED, 'Id of system user')
+			 ->addArgument('cid', InputArgument::REQUIRED, 'Id of calendar')
+			 ->addArgument('format', InputArgument::OPTIONAL, 'Format of output (iCal, jCal, xCal) default to iCal')
+			 ->addArgument('location', InputArgument::OPTIONAL, 'location of where to write the output. defaults to stdout');
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		
+		$userId = $input->getArgument('uid');
+		$calendarId = $input->getArgument('cid');
+		$format = $input->getArgument('format');
+		$location = $input->getArgument('location');
+
+		if (!$this->userManager->userExists($userId)) {
+			throw new \InvalidArgumentException("User <$userId> not found.");
+		}
+		// retrieve calendar and evaluate if export is supported
+		$calendars = $this->calendarManager->getCalendarsForPrincipal('principals/users/' . $userId, [$calendarId]);
+		if ($calendars === []) {
+			throw new \InvalidArgumentException("Calendar <$calendarId> not found.");
+		}
+		$calendar = $calendars[0];
+		/*
+		if ($calendar instanceof ICalendarExport) {
+			throw new \InvalidArgumentException("Calendar <$calendarId> dose support this function");
+		}
+		*/
+		// evaluate if requested format is supported
+		if ($format !== null && !in_array($format, $this->exportService::FORMATS)) {
+			throw new \InvalidArgumentException("Format <$format> is not valid.");
+		} elseif ($format === null) {
+			$format = 'ical';
+		}
+		// evaluate is a valid location was given and is usable otherwise output to stdout
+		if ($location !== null) {
+			$handle = fopen($location, "w");
+			if ($handle === false) {
+				throw new \InvalidArgumentException("Location <$location> is not valid. Can not open location for write operation.");
+			} else {
+
+				fwrite($handle, "BEGIN:VCALENDAR\nVERSION:2.0\nPRODID:-//IDN nextcloud.com//Calendar App//EN\n");
+				
+
+				for ($i=0; $i < 16384; $i++) { 
+					
+				$id = uniqid();
+				fwrite(
+					$handle,
+'BEGIN:VEVENT
+CREATED:20240910T123608Z
+LAST-MODIFIED:20240916T075225Z
+DTSTAMP:20240916T075225Z
+UID:' . $id . PHP_EOL .
+'SUMMARY:Brainstorming workshop- Collectives - Room A
+STATUS:CONFIRMED
+ORGANIZER;CN=Irina Mikhaylina;SCHEDULE-STATUS=1.1:mailto:irina.mikhaylina@n
+ extcloud.com
+ATTENDEE;RSVP=TRUE;CN=Jonas Meurer;PARTSTAT=NEEDS-ACTION;CUTYPE=INDIVIDUAL;
+ ROLE=REQ-PARTICIPANT;LANGUAGE=en;SCHEDULE-STATUS=1.1:mailto:jonas.meurer@n
+ extcloud.com
+ATTENDEE;RSVP=TRUE;CN=Simon Lindner;PARTSTAT=NEEDS-ACTION;CUTYPE=INDIVIDUAL
+ ;ROLE=REQ-PARTICIPANT;LANGUAGE=en;SCHEDULE-STATUS=1.1:mailto:simon.lindner
+ @nextcloud.com
+ATTENDEE;RSVP=TRUE;CN=Louis Chemineau;PARTSTAT=NEEDS-ACTION;CUTYPE=INDIVIDU
+ AL;ROLE=REQ-PARTICIPANT;LANGUAGE=en;SCHEDULE-STATUS=1.1:mailto:louis.chemi
+ neau@nextcloud.com
+ATTENDEE;RSVP=TRUE;CN=Jenna Stocks;PARTSTAT=NEEDS-ACTION;CUTYPE=INDIVIDUAL;
+ ROLE=REQ-PARTICIPANT;LANGUAGE=en_GB;SCHEDULE-STATUS=1.1:mailto:jenna.stock
+ s@nextcloud.com
+ATTENDEE;RSVP=TRUE;CN=Marcel Hibbe;PARTSTAT=NEEDS-ACTION;CUTYPE=INDIVIDUAL;
+ ROLE=REQ-PARTICIPANT;LANGUAGE=en;SCHEDULE-STATUS=1.1:mailto:marcel.hibbe@n
+ extcloud.com
+ATTENDEE;RSVP=TRUE;CN=Peter Mocanu;PARTSTAT=NEEDS-ACTION;CUTYPE=INDIVIDUAL;
+ ROLE=REQ-PARTICIPANT;LANGUAGE=en;SCHEDULE-STATUS=1.1:mailto:peter.mocanu@n
+ extcloud.com
+ATTENDEE;RSVP=TRUE;CN=Cyprien Edouard;PARTSTAT=NEEDS-ACTION;CUTYPE=INDIVIDU
+ AL;ROLE=REQ-PARTICIPANT;LANGUAGE=en;SCHEDULE-STATUS=1.1:mailto:cyprien.edo
+ uard@nextcloud.com
+ATTENDEE;RSVP=TRUE;CN=Kim Pohlmann;PARTSTAT=NEEDS-ACTION;CUTYPE=INDIVIDUAL;
+ ROLE=REQ-PARTICIPANT;LANGUAGE=de;SCHEDULE-STATUS=1.1:mailto:kim.pohlmann@n
+ extcloud.com
+ATTENDEE;RSVP=TRUE;CN=Tobias Kaminsky;PARTSTAT=ACCEPTED;CUTYPE=INDIVIDUAL;R
+ OLE=REQ-PARTICIPANT;LANGUAGE=en;SCHEDULE-STATUS=1.1:mailto:tobias.kaminsky
+ @nextcloud.com
+DTSTART;TZID=Europe/Berlin:20240919T100000
+DTEND;TZID=Europe/Berlin:20240919T110000
+SEQUENCE:4
+LOCATION:Room A (ground floor)
+DESCRIPTION:Hello dear team\,  \n  \nwe would like to invite you to join ou
+ r upcoming Product Brainstorming Session\, where we will come together in 
+ a group of 10 people to spark creativity and collaborate on potential new 
+ features for Nextcloud apps 💥  Here is the structure of the session:\n\
+ n1. Introduction (5 minutes): We\'ll start with a brief introduction from t
+ he design team\, followed by participants introducing themselves. To make 
+ things fun and relaxed\, we\'ll choose a moderator from the group. We’ll 
+ just ask for volunteers on the spot\, so no one feels pressured or assigne
+ d without their agreement.\n\n2. App Demo (10 minutes): Next\, the develop
+ er of each team will share their screen and give a short demo of the app\,
+  walking everyone through its current features and explaining what it does
+ .\n\n3. Idea Generation (10 minutes): After the demo\, it\'s time for every
+ one to jot down ideas for new features or improvements they\'d like to see.
+  You can come up with up to 5 ideas and stick them on a whiteboard for us 
+ all to review.\n\n4. Discussion (25 minutes): The moderator will then go t
+ hrough each idea on the board. The person who wrote it will explain their 
+ thought process\, and then we’ll open the floor for feedback. Everyone c
+ an share whether they agree\, disagree\, or offer praise and suggestions.\
+ n\n5. Prioritization (10 minutes): We’ll pick the most important ideas b
+ ased on our discussion.\n\nThroughout the session\, the moderator will kee
+ p track of time and ensure we don’t spend too long on any one idea 🤓 
+ \n\nIf you have any questions\, feel free to reach out with me!\n\nKind re
+ gards\nIrina
+X-MOZ-GENERATION:1
+END:VEVENT
+'
+				);
+			}
+			fwrite($handle, "END:VCALENDAR\n");
+				/*
+				foreach ($this->exportService->export($calendar, $format) as $chunk) {
+					fwrite($handle, $chunk);
+				}
+				*/
+				fclose($handle);
+			}
+		} else {
+			foreach ($this->exportService->export($calendar, $format) as $chunk) {
+				$output->writeln($chunk);
+			}
+		}
+
+		return self::SUCCESS;
+	}
+}
diff --git a/lib/Command/Import.php b/lib/Command/Import.php
new file mode 100644
index 000000000..4786623fd
--- /dev/null
+++ b/lib/Command/Import.php
@@ -0,0 +1,102 @@
+<?php
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\Calendar\Command;
+
+use OCA\Calendar\Service\Import\ImportService;
+use OCP\Calendar\CalendarImportSettings;
+use OCP\Calendar\ICalendarImport;
+use OCP\Calendar\IManager;
+use OCP\IUserManager;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class Import extends Command {
+	public function __construct(
+		private IUserManager $userManager,
+		private IManager $calendarManager,
+		private ImportService $importService,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		$this->setName('calendar:import')
+			 ->setDescription('Import a file or stream')
+			 ->addArgument('uid', InputArgument::REQUIRED, 'Id of system user')
+			 ->addArgument('cid', InputArgument::REQUIRED, 'Id of calendar')
+			 ->addArgument('format', InputArgument::OPTIONAL, 'Format of output (iCal, jCal, xCal) default to iCal')
+			 ->addArgument('location', InputArgument::OPTIONAL, 'location of where to write the output. defaults to stdin');
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		
+		$userId = $input->getArgument('uid');
+		$calendarId = $input->getArgument('cid');
+		$format = $input->getArgument('format');
+		$location = $input->getArgument('location');
+
+		if (!$this->userManager->userExists($userId)) {
+			throw new \InvalidArgumentException("User <$userId> not found.");
+		}
+		// retrieve calendar and evaluate if import is supported and writeable
+		$calendars = $this->calendarManager->getCalendarsForPrincipal('principals/users/' . $userId, [$calendarId]);
+		if ($calendars === []) {
+			throw new \InvalidArgumentException("Calendar <$calendarId> not found.");
+		}
+		$calendar = $calendars[0];
+		if ($calendar instanceof ICalendarImport) {
+			//throw new \InvalidArgumentException("Calendar <$calendarId> dose support this function");
+		}
+		if (!$calendar->isWritable()) {
+			throw new \InvalidArgumentException("Calendar <$calendarId> is not writeable");
+		}
+		if ($calendar->isDeleted()) {
+			throw new \InvalidArgumentException("Calendar <$calendarId> is deleted");
+		}
+		// construct settings object
+		$settings = new CalendarImportSettings();
+		// evaluate if provided format is supported
+		if ($format !== null && !in_array($format, $this->importService::FORMATS)) {
+			throw new \InvalidArgumentException("Format <$format> is not valid.");
+		} elseif ($format === null) {
+			$settings->format = 'ical';
+		}
+		// evaluate if a valid location was given and is usable otherwise default to stdin
+		if ($location !== null) {
+			$input = fopen($location, "r");
+			if ($input === false) {
+				throw new \InvalidArgumentException("Location <$location> is not valid. Can not open location for read operation.");
+			} else {
+				try {
+					$this->importService->import($input, $calendar, $settings);
+				} finally {
+					fclose($input);
+				}
+			}
+		} else {
+			$input = fopen('php://stdin', 'r');
+			if ($input === false) {
+				throw new \InvalidArgumentException("Can not open stdin for read operation.");
+			} else {
+				try {
+					$temp = tmpfile();
+					while (!feof($input)) {
+						fwrite($temp, fread($input, 8192));
+					}
+					fseek($temp, 0);
+					$this->importService->import($temp, $calendar, $settings);
+				} finally {
+					fclose($input);
+					fclose($temp);
+				}
+			}
+		}
+
+		return self::SUCCESS;
+	}
+}
diff --git a/lib/Controller/ExportController.php b/lib/Controller/ExportController.php
new file mode 100644
index 000000000..6d4f67916
--- /dev/null
+++ b/lib/Controller/ExportController.php
@@ -0,0 +1,90 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\Calendar\Controller;
+
+use OCA\Calendar\AppInfo\Application;
+use OCA\Calendar\Service\Export\ExportService;
+use OCP\AppFramework\Controller;
+use OCP\AppFramework\Http;
+use OCP\AppFramework\Http\Attribute\ApiRoute;
+use OCP\AppFramework\Http\Attribute\NoAdminRequired;
+use OCP\AppFramework\Http\Attribute\UserRateLimit;
+use OCP\AppFramework\Http\DataResponse;
+use OCP\AppFramework\Http\StreamGeneratorResponse;
+use OCP\Calendar\ICalendarExport;
+use OCP\Calendar\IManager;
+use OCP\IGroupManager;
+use OCP\IRequest;
+use OCP\IUserManager;
+use OCP\IUserSession;
+
+class ExportController extends Controller {
+
+	public function __construct(
+		IRequest $request,
+		private IUserSession $userSession,
+		private IUserManager $userManager,
+		private IGroupManager $groupManager,
+		private IManager $calendarManager,
+		private ExportService $exportService
+	) {
+		parent::__construct(Application::APP_ID, $request);
+	}
+	
+	#[ApiRoute(verb: 'GET', url: '/export', root: '/calendar')]
+	#[ApiRoute(verb: 'POST', url: '/export', root: '/calendar')]
+	#[UserRateLimit(limit: 1, period: 60)]
+	#[NoAdminRequired]
+	public function index(string $id, ?string $fmt = null, ?string $user = null) {
+		
+		$userId = $user;
+		$calendarId = $id;
+		$format = $fmt;
+		// evaluate if user is logged in and has permissions
+		if (!$this->userSession->isLoggedIn()) {
+			return new DataResponse([], Http::STATUS_UNAUTHORIZED);
+		}
+		if ($userId !== null) {
+			if (!$this->groupManager->isAdmin($this->userSession->getUser()->getUID()) &&
+				$this->userSession->getUser()->getUID() !== $userId) {
+				return new DataResponse([], Http::STATUS_UNAUTHORIZED);
+			}
+			if (!$this->userManager->userExists($userId)) {
+				return new DataResponse(['error' => 'user not found'], Http::STATUS_BAD_REQUEST);
+			}
+		} else {
+			$userId = $this->userSession->getUser()->getUID();
+		}
+		// retrieve calendar and evaluate if export is supported
+		$calendars = $this->calendarManager->getCalendarsForPrincipal('principals/users/' . $userId, [$calendarId]);
+		if ($calendars === []) {
+			return new DataResponse(['error' => 'calendar not found'], Http::STATUS_BAD_REQUEST);
+		}
+		$calendar = $calendars[0];
+		/*
+		if ($calendar instanceof ICalendarExport) {
+			return new DataResponse(['error' => 'calendar export not supported'], Http::STATUS_BAD_REQUEST);
+		}
+		*/
+		// evaluate if requested format is supported and convert to output content type
+		if ($format !== null && !in_array($format, $this->exportService::FORMATS)) {
+			return new DataResponse(['error' => 'format invalid'], Http::STATUS_BAD_REQUEST);
+		} elseif ($format === null) {
+			$format = 'ical';
+		}
+		$contentType = match (strtolower($format)) {
+			'jcal' => 'application/calendar+json; charset=UTF-8',
+			'xcal' => 'application/calendar+xml; charset=UTF-8',
+			default => 'text/calendar; charset=UTF-8'
+		};
+
+		return new StreamGeneratorResponse($this->exportService->export($calendar, $format), $contentType);
+
+	}
+}
diff --git a/lib/Service/Export/ExportService.php b/lib/Service/Export/ExportService.php
new file mode 100644
index 000000000..473b81459
--- /dev/null
+++ b/lib/Service/Export/ExportService.php
@@ -0,0 +1,103 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2020 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\Calendar\Service\Export;
+
+use Generator;
+use OCP\Calendar\CalendarExportRange;
+use OCP\Calendar\ICalendar;
+use OCP\Calendar\ICalendarExport;
+use Sabre\VObject\Component;
+use Sabre\VObject\Writer;
+
+class ExportService {
+	
+	public const FORMATS = ['ical', 'jcal', 'xcal'];
+
+	public function __construct() {}
+
+	/**
+	 * Retrieves calendar object, converts each object to appropriate format and streams output
+	 */
+	public function export(ICalendar&ICalendarExport $calendar, string $format, ?CalendarExportRange $range = null): Generator {
+
+		yield $this->exportStart($format);
+
+		// iterate through each returned vCalendar entry
+		// extract each vObject type, convert to appropriate format and output
+		// extract any vTimezones objects and save them but do not output
+		$timezones = [];
+		foreach ($calendar->export($range) as $entry) {
+			$consecutive = false;
+			foreach ($entry->getComponents() as $vComponent) {
+				if ($vComponent->name !== 'VTIMEZONE') {
+					yield $this->exportObject($vComponent, $format, $consecutive);
+					$consecutive = true;
+				}
+				if ($vComponent->name === 'VTIMEZONE') {
+					if (isset($vComponent->TZID) && !isset($timezones[$vComponent->TZID->getValue()])) {
+						$timezones[$vComponent->TZID->getValue()] = clone $vComponent;
+					}
+				}
+			}
+		}
+		// iterate through each vTimezone entry, convert to appropriate format and output
+		foreach ($timezones as $vComponent) {
+			yield $this->exportObject($vComponent, $format, $consecutive);
+			$consecutive = true;
+		}
+
+		yield $this->exportFinish($format);
+
+	}
+
+	/**
+	 * Generates appropriate output start based on selected format
+	 */
+	private function exportStart(string $format): string {
+		return match ($format) {
+			'jcal' => '["vcalendar",[["version",{},"text","2.0"],["prodid",{},"text","-\/\/IDN nextcloud.com\/\/Calendar App\/\/EN"]],[',
+			'xcal' => '<?xml version="1.0" encoding="UTF-8"?><icalendar xmlns="urn:ietf:params:xml:ns:icalendar-2.0"><vcalendar><properties><version><text>2.0</text></version><prodid><text>-//IDN nextcloud.com//Calendar App//EN</text></prodid></properties><components>',
+			default => "BEGIN:VCALENDAR\nVERSION:2.0\nPRODID:-//IDN nextcloud.com//Calendar App//EN\n"
+		};
+	}
+
+	/**
+	 * Generates appropriate output end based on selected format
+	 */
+	private function exportFinish(string $format): string {
+		return match ($format) {
+			'jcal' => ']]',
+			'xcal' => '</components></vcalendar></icalendar>',
+			default => "END:VCALENDAR\n"
+		};
+	}
+
+	/**
+	 * Generates appropriate output content for a component based on selected format
+	 */
+	private function exportObject(Component $vobject, string $format, bool $consecutive): string {
+		return match ($format) {
+			'jcal' => $consecutive ? ',' . Writer::writeJson($vobject) : Writer::writeJson($vobject),
+			'xcal' => $this->exportObjectXml($vobject),
+			default => Writer::write($vobject)
+		};
+	}
+	
+	/**
+	 * Generates appropriate output content for a component for xml format
+	 */
+	private function exportObjectXml(Component $vobject): string {
+		$writer = new \Sabre\Xml\Writer();
+        $writer->openMemory();
+        $writer->setIndent(false);
+        $vobject->xmlSerialize($writer);
+        return $writer->outputMemory();
+	}
+
+}
diff --git a/lib/Service/Import/ImportService.php b/lib/Service/Import/ImportService.php
new file mode 100644
index 000000000..0f1c70f5a
--- /dev/null
+++ b/lib/Service/Import/ImportService.php
@@ -0,0 +1,247 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2020 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\Calendar\Service\Import;
+
+use Exception;
+use OCP\Calendar\CalendarImportSettings;
+use OCP\Calendar\ICalendar;
+use OCP\Calendar\ICalendarImport;
+use Sabre\VObject\Component\VCalendar;
+use Sabre\VObject\Node;
+use Sabre\VObject\Reader;
+
+class ImportService {
+	
+	public const FORMATS = ['ical', 'jcal', 'xcal'];
+
+	public function __construct() {}
+
+	/**
+	 * Retrieves calendar object, converts each object to appropriate format and streams output
+	 */
+	public function import($stream, ICalendar $calendar, CalendarImportSettings $settings): void {
+
+		$time_start = microtime(true);
+
+		echo "\nMemory usage: " . memory_get_usage()/1048576;
+		
+		//Reader::read($stream);
+
+		switch ($settings->format) {
+			case 'ical':
+				$this->importICal($stream, $calendar, $settings);
+				break;
+			case 'jcal':
+				$this->importICal($stream, $calendar, $settings);
+				break;
+			case 'xcal':
+				$this->importICal($stream, $calendar, $settings);
+				break;
+		}
+
+		$time_end = microtime(true);
+
+		$execution_time = ($time_end - $time_start);
+
+		echo "\nProcessing time: " . $execution_time;
+		echo "\n";
+
+	}
+
+	private function importICal($stream, ICalendar $calendar, CalendarImportSettings $settings): void {
+
+		$outcome = [];
+		$structure = $this->analyzeICal($stream);
+
+		$vStart = "BEGIN:VCALENDAR" . PHP_EOL;
+		$vEnd = PHP_EOL . "END:VCALENDAR";
+
+		// calendar properties
+		foreach ($structure['VCALENDAR'] as $entry) {
+			$vStart .= $entry;
+			if (!substr($entry, -1) === "\n" || !substr($entry, -2) === "\r\n") {
+				$vStart .= PHP_EOL;
+			}
+		}
+
+		// calendar time zones
+		$timezones = [];
+		foreach ($structure['VTIMEZONE'] as $tid => $collection) {
+			$instance = $collection[0];
+			$vData = $this->extractICalData($stream, $instance[2], $instance[3]);
+			$vObject = Reader::read($vStart . $vData . $vEnd);
+			$timezones[$tid] = clone $vObject->VTIMEZONE;
+		}
+
+		// calendar components
+		$components = [];
+		foreach ($structure['VEVENT'] as $cid => $collection) {
+			// extract and unserialize components
+			$vData = "";
+			foreach ($collection as $instance) {
+				$vData .= $this->extractICalData($stream, $instance[2], $instance[3]);
+			}
+			/** @var VCalendar $vObject */
+			$vObject = Reader::read($vStart . $vData . $vEnd);
+			// extract all timezones from properties for all instances
+			$vObjectTZ = [];
+			foreach ($vObject->getComponents() as $vComponent) {
+				if ($vComponent->name !== 'VTIMEZONE') {
+					foreach (['DTSTART', 'DTEND', 'DUE', 'RDATE', 'EXDATE'] as $property) {
+						if (isset($vComponent->$property?->parameters['TZID'])) {
+							$tid = $vComponent->$property->parameters['TZID']->getValue();
+							if (isset($timezones[$tid]) && !isset($vObjectTZ[$tid])) {
+								$vObjectTZ[$tid] = clone $timezones[$tid];
+							}
+						}
+					}
+				}
+			}
+			// add time zones to object
+			foreach ($vObjectTZ as $zone) {
+				$vObject->add($zone);
+			}
+			// validate object
+			if ($settings->validate !== 0) {
+				$issues = $this->validateComponent($vObject, true, 3);
+			} else {
+				$issues = [];
+			}
+			if ($settings->validate === 1 && $issues !== []) {
+				$outcome[$cid] = $issues;
+				continue;
+			}
+			if ($settings->validate === 2 && $issues !== []) {
+				throw new Exception('Error importing calendar object <' . $cid . '> ' . $issues[0]);
+			}
+			// add objects to collection until max batch size is reached
+			if ($settings->bulk > count($components)) {
+				$components[] = $vObject;
+			}
+			// save collection to storage if max batch size is reached
+			if ($settings->bulk <= count($components)) {
+				$calendar->import($settings, ...$components);
+				$components = [];
+			}
+		}
+
+		// save collection to storage if max bulk was not reached
+		if (count($components) > 0) {
+			$calendar->import($settings, ...$components);
+			$components = [];
+		}
+
+	}
+
+	private function validateComponent(VCalendar $vObject, bool $repair, int $level): array {
+		// validate component(S)
+		$issues = $vObject->validate(Node::PROFILE_CALDAV);
+		// attempt to repair
+		if ($repair && count($issues) > 0) {
+			$issues = $vObject->validate(Node::REPAIR);
+		}
+		// filter out messages based on level
+		$result = [];
+		foreach ($issues as $key => $issue) {
+			if (isset($issue['level']) && $issue['level'] >= $level) {
+				$result[] = $issue['message'];
+			}
+		}
+
+		return $result;
+	}
+
+	private function analyzeICal($stream): array {
+
+		$tags = ['VEVENT', 'VTODO', 'VJOURNAL', 'VTIMEZONE'];
+
+		$components = ['VCALENDAR' => [], 'VEVENT' => [], 'VTODO' => [], 'VJOURNAL' => [], 'VTIMEZONE' => []];
+		$componentStart = null;
+		$componentEnd = null;
+		$componentId = null;
+		$componentType = null;
+
+		fseek($stream, 0);
+		while(!feof($stream)) {
+			$data = fgets($stream);
+
+			if ($data === false || empty(trim($data))) {
+				continue;
+			}
+			
+			if (ctype_space($data[0]) === false) {
+			
+				if (str_starts_with($data, 'BEGIN:')) {
+					$type = trim(substr($data, 6));
+					if (in_array($type, $tags)) {
+						$componentStart = ftell($stream) - strlen($data);
+						$componentType = $type;
+					}
+					unset($type);
+				}
+				
+				if (str_starts_with($data, 'END:')) {
+					$type = trim(substr($data, 4));
+					if ($componentType === $type) {
+						$componentEnd = ftell($stream);
+					}
+					unset($type);
+				}
+
+				if ($componentStart !== null && str_starts_with($data, 'UID:')) {
+					$componentId = trim(substr($data, 5));
+				}
+
+				if ($componentStart !== null && str_starts_with($data, 'TZID:')) {
+					$componentId = trim(substr($data, 5));
+				}
+				
+			}
+
+			if ($componentStart === null) {
+				if (!str_starts_with($data, 'BEGIN:VCALENDAR') && !str_starts_with($data, 'END:VCALENDAR')) {
+					$components['VCALENDAR'][] = $data;
+				}
+			}
+
+			if ($componentEnd !== null) {
+				if ($componentId !== null) {
+					$components[$componentType][$componentId][] = [
+						$componentType,
+						$componentId,
+						$componentStart,
+						$componentEnd	
+					];
+				} else {
+					$components[$componentType][] = [
+						$componentType,
+						$componentId,
+						$componentStart,
+						$componentEnd	
+					];
+				}
+				$componentId = null;
+				$componentType = null;
+				$componentStart = null;
+				$componentEnd = null;
+			}
+			
+		}
+		
+		return $components;
+	}
+
+	private function extractICalData($stream, int $start, $end): string {
+	
+		fseek($stream, $start);
+		return fread($stream, $end - $start);
+
+	}
+
+}