feat: calendar federation write

Signed-off-by: SebastianKrupinski <krupinskis05@gmail.com>

apps/dav/composer/composer/autoload_classmap.php

@@ -77,6 +77,7 @@ return array(
     'OCA\\DAV\\CalDAV\\Federation\\FederatedCalendarFactory' => $baseDir . '/../lib/CalDAV/Federation/FederatedCalendarFactory.php',
     'OCA\\DAV\\CalDAV\\Federation\\FederatedCalendarImpl' => $baseDir . '/../lib/CalDAV/Federation/FederatedCalendarImpl.php',
     'OCA\\DAV\\CalDAV\\Federation\\FederatedCalendarMapper' => $baseDir . '/../lib/CalDAV/Federation/FederatedCalendarMapper.php',
+    'OCA\\DAV\\CalDAV\\Federation\\FederatedCalendarObject' => $baseDir . '/../lib/CalDAV/Federation/FederatedCalendarObject.php',
     'OCA\\DAV\\CalDAV\\Federation\\FederatedCalendarSyncService' => $baseDir . '/../lib/CalDAV/Federation/FederatedCalendarSyncService.php',
     'OCA\\DAV\\CalDAV\\Federation\\FederationSharingService' => $baseDir . '/../lib/CalDAV/Federation/FederationSharingService.php',
     'OCA\\DAV\\CalDAV\\Federation\\Protocol\\CalendarFederationProtocolV1' => $baseDir . '/../lib/CalDAV/Federation/Protocol/CalendarFederationProtocolV1.php',

apps/dav/composer/composer/autoload_static.php

@@ -92,6 +92,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\CalDAV\\Federation\\FederatedCalendarFactory' => __DIR__ . '/..' . '/../lib/CalDAV/Federation/FederatedCalendarFactory.php',
         'OCA\\DAV\\CalDAV\\Federation\\FederatedCalendarImpl' => __DIR__ . '/..' . '/../lib/CalDAV/Federation/FederatedCalendarImpl.php',
         'OCA\\DAV\\CalDAV\\Federation\\FederatedCalendarMapper' => __DIR__ . '/..' . '/../lib/CalDAV/Federation/FederatedCalendarMapper.php',
+        'OCA\\DAV\\CalDAV\\Federation\\FederatedCalendarObject' => __DIR__ . '/..' . '/../lib/CalDAV/Federation/FederatedCalendarObject.php',
         'OCA\\DAV\\CalDAV\\Federation\\FederatedCalendarSyncService' => __DIR__ . '/..' . '/../lib/CalDAV/Federation/FederatedCalendarSyncService.php',
         'OCA\\DAV\\CalDAV\\Federation\\FederationSharingService' => __DIR__ . '/..' . '/../lib/CalDAV/Federation/FederationSharingService.php',
         'OCA\\DAV\\CalDAV\\Federation\\Protocol\\CalendarFederationProtocolV1' => __DIR__ . '/..' . '/../lib/CalDAV/Federation/Protocol/CalendarFederationProtocolV1.php',

apps/dav/lib/CalDAV/CalendarProvider.php

@@ -43,9 +43,9 @@ class CalendarProvider implements ICalendarProvider {
 			});
 		}
 
-		$additionalProperties = $this->getAdditionalPropertiesForCalendars($calendarInfos);
 		$iCalendars = [];
 
+		$additionalProperties = $this->getAdditionalPropertiesForCalendars($calendarInfos);
 		foreach ($calendarInfos as $calendarInfo) {
 			$user = str_replace('principals/users/', '', $calendarInfo['principaluri']);
 			$path = 'calendars/' . $user . '/' . $calendarInfo['uri'];
@@ -60,14 +60,12 @@ class CalendarProvider implements ICalendarProvider {
 			);
 		}
 
-		$additionalFederatedProps = $this->getAdditionalPropertiesForCalendars(
-			$federatedCalendarInfos,
-		);
+		$additionalFederatedProps = $this->getAdditionalPropertiesForCalendars($federatedCalendarInfos);
 		foreach ($federatedCalendarInfos as $calendarInfo) {
 			$user = str_replace('principals/users/', '', $calendarInfo['principaluri']);
 			$path = 'calendars/' . $user . '/' . $calendarInfo['uri'];
 			if (isset($additionalFederatedProps[$path])) {
-				$calendarInfo = array_merge($calendarInfo, $additionalProperties[$path]);
+				$calendarInfo = array_merge($calendarInfo, $additionalFederatedProps[$path]);
 			}
 
 			$iCalendars[] = new FederatedCalendarImpl($calendarInfo, $this->calDavBackend);

apps/dav/lib/CalDAV/Federation/CalendarFederationProvider.php

@@ -104,9 +104,10 @@ class CalendarFederationProvider implements ICloudFederationProvider {
 			);
 		}
 
-		// TODO: implement read-write sharing
+		// convert access to permissions
 		$permissions = match ($access) {
 			DavSharingBackend::ACCESS_READ => Constants::PERMISSION_READ,
+			DavSharingBackend::ACCESS_READ_WRITE => Constants::PERMISSION_READ | Constants::PERMISSION_CREATE | Constants::PERMISSION_UPDATE | Constants::PERMISSION_DELETE,
 			default => throw new ProviderCouldNotAddShareException(
 				"Unsupported access value: $access",
 				'',
@@ -122,20 +123,27 @@ class CalendarFederationProvider implements ICloudFederationProvider {
 		$sharedWithPrincipal = 'principals/users/' . $share->getShareWith();
 
 		// Delete existing incoming federated share first
-		$this->federatedCalendarMapper->deleteByUri($sharedWithPrincipal, $calendarUri);
+		$calendar = $this->federatedCalendarMapper->findByUri($sharedWithPrincipal, $calendarUri);
 
-		$calendar = new FederatedCalendarEntity();
-		$calendar->setPrincipaluri($sharedWithPrincipal);
-		$calendar->setUri($calendarUri);
-		$calendar->setRemoteUrl($calendarUrl);
-		$calendar->setDisplayName($displayName);
-		$calendar->setColor($color);
-		$calendar->setToken($share->getShareSecret());
-		$calendar->setSharedBy($share->getSharedBy());
-		$calendar->setSharedByDisplayName($share->getSharedByDisplayName());
-		$calendar->setPermissions($permissions);
-		$calendar->setComponents($components);
-		$calendar = $this->federatedCalendarMapper->insert($calendar);
+		if ($calendar === null) {
+			$calendar = new FederatedCalendarEntity();
+			$calendar->setPrincipaluri($sharedWithPrincipal);
+			$calendar->setUri($calendarUri);
+			$calendar->setRemoteUrl($calendarUrl);
+			$calendar->setDisplayName($displayName);
+			$calendar->setColor($color);
+			$calendar->setToken($share->getShareSecret());
+			$calendar->setSharedBy($share->getSharedBy());
+			$calendar->setSharedByDisplayName($share->getSharedByDisplayName());
+			$calendar->setPermissions($permissions);
+			$calendar->setComponents($components);
+			$calendar = $this->federatedCalendarMapper->insert($calendar);
+		} else {
+			$calendar->setToken($share->getShareSecret());
+			$calendar->setPermissions($permissions);
+			$calendar->setComponents($components);
+			$this->federatedCalendarMapper->update($calendar);
+		}
 
 		$this->jobList->add(FederatedCalendarSyncJob::class, [
 			FederatedCalendarSyncJob::ARGUMENT_ID => $calendar->getId(),

apps/dav/lib/CalDAV/Federation/FederatedCalendar.php

@@ -10,29 +10,251 @@ declare(strict_types=1);
 namespace OCA\DAV\CalDAV\Federation;
 
 use OCA\DAV\CalDAV\CalDavBackend;
-use OCA\DAV\CalDAV\Calendar;
-use OCP\IConfig;
-use OCP\IL10N;
+use OCP\Constants;
 use Psr\Log\LoggerInterface;
 use Sabre\CalDAV\Backend;
+use Sabre\CalDAV\ICalendar;
+use Sabre\CalDAV\Plugin;
+use Sabre\CalDAV\Xml\Property\SupportedCalendarComponentSet;
+use Sabre\DAV\Exception\MethodNotAllowed;
+use Sabre\DAV\Exception\NotFound;
+use Sabre\DAV\IMultiGet;
+use Sabre\DAV\IProperties;
+use Sabre\DAV\PropPatch;
+
+class FederatedCalendar implements ICalendar, IProperties, IMultiGet {
+
+	private const CALENDAR_TYPE = CalDavBackend::CALENDAR_TYPE_FEDERATED;
+	private const DAV_PROPERTY_CALENDAR_LABEL = '{DAV:}displayname';
+	private const DAV_PROPERTY_CALENDAR_COLOR = '{http://apple.com/ns/ical/}calendar-color';
+
+	private string $principalUri;
+	private int $calendarId;
+	private string $calendarUri;
+	private FederatedCalendarEntity $federationInfo;
 
-class FederatedCalendar extends Calendar {
 	public function __construct(
-		Backend\BackendInterface $caldavBackend,
-		$calendarInfo,
-		IL10N $l10n,
-		IConfig $config,
-		LoggerInterface $logger,
+		private readonly LoggerInterface $logger,
 		private readonly FederatedCalendarMapper $federatedCalendarMapper,
+		private readonly FederatedCalendarSyncService $federatedCalendarService,
+		private readonly Backend\BackendInterface $caldavBackend,
+		$calendarInfo,
 	) {
-		parent::__construct($caldavBackend, $calendarInfo, $l10n, $config, $logger);
+		$this->principalUri = $calendarInfo['principaluri'];
+		$this->calendarId = $calendarInfo['id'];
+		$this->calendarUri = $calendarInfo['uri'];
+		$this->federationInfo = $federatedCalendarMapper->findByUri($this->principalUri, $this->calendarUri);
+	}
+
+	public function getResourceId(): int {
+		return $this->federationInfo->getId();
+	}
+
+	public function getName() {
+		return $this->federationInfo->getUri();
+	}
+
+	public function setName($name) {
+		throw new MethodNotAllowed('Renaming federated calendars is not allowed');
+	}
+
+	protected function getCalendarType(): int {
+		return self::CALENDAR_TYPE;
+	}
+
+	public function getPrincipalURI() {
+		return $this->federationInfo->getPrincipaluri();
+	}
+
+	public function getOwner() {
+		return $this->federationInfo->getSharedByPrincipal();
+	}
+
+	public function getGroup() {
+		return null;
+	}
+
+	public function getACL() {
+
+		$permissions = $this->federationInfo->getPermissions();
+		// default permission
+		$acl = [
+			// read object permission
+			[
+				'privilege' => '{DAV:}read',
+				'principal' => $this->principalUri,
+				'protected' => true,
+			],
+			// read acl permission
+			[
+				'privilege' => '{DAV:}read-acl',
+				'principal' => $this->principalUri,
+				'protected' => true,
+			],
+			// write properties permission (calendar name, color)
+			[
+				'privilege' => '{DAV:}write-properties',
+				'principal' => $this->principalUri,
+				'protected' => true,
+			],
+		];
+		// create permission
+		if ($permissions & Constants::PERMISSION_CREATE) {
+			$acl[] = [
+				'privilege' => '{DAV:}bind',
+				'principal' => $this->principalUri,
+				'protected' => true,
+			];
+		}
+		// update permission
+		if ($permissions & Constants::PERMISSION_UPDATE) {
+			$acl[] = [
+				'privilege' => '{DAV:}write-content',
+				'principal' => $this->principalUri,
+				'protected' => true,
+			];
+		}
+		// delete permission
+		if ($permissions & Constants::PERMISSION_DELETE) {
+			$acl[] = [
+				'privilege' => '{DAV:}unbind',
+				'principal' => $this->principalUri,
+				'protected' => true,
+			];
+		}
+
+		return $acl;
+	}
+
+	public function setACL(array $acl) {
+		throw new MethodNotAllowed('Changing ACLs on federated calendars is not allowed');
+	}
+
+	public function getSupportedPrivilegeSet(): ?array {
+		return null;
+	}
+
+	public function getProperties($properties): array {
+		return [
+			self::DAV_PROPERTY_CALENDAR_LABEL => $this->federationInfo->getDisplayName(),
+			self::DAV_PROPERTY_CALENDAR_COLOR => $this->federationInfo->getColor(),
+			'{' . Plugin::NS_CALDAV . '}supported-calendar-component-set' => new SupportedCalendarComponentSet(explode(',', $this->federationInfo->getComponents())),
+		];
+	}
+
+	public function propPatch(PropPatch $propPatch): void {
+		$mutations = $propPatch->getMutations();
+		if (count($mutations) > 0) {
+			// evaluate if name was changed
+			if (isset($mutations[self::DAV_PROPERTY_CALENDAR_LABEL])) {
+				$this->federationInfo->setDisplayName($mutations[self::DAV_PROPERTY_CALENDAR_LABEL]);
+				$propPatch->setResultCode(self::DAV_PROPERTY_CALENDAR_LABEL, 200);
+			}
+			// evaluate if color was changed
+			if (isset($mutations[self::DAV_PROPERTY_CALENDAR_COLOR])) {
+				$this->federationInfo->setColor($mutations[self::DAV_PROPERTY_CALENDAR_COLOR]);
+				$propPatch->setResultCode(self::DAV_PROPERTY_CALENDAR_COLOR, 200);
+			}
+			$this->federatedCalendarMapper->update($this->federationInfo);
+		}
+	}
+
+
+	public function getChildACL() {
+		return $this->getACL();
+	}
+
+	public function getLastModified() {
+		return $this->federationInfo->getLastSync();
 	}
 
 	public function delete() {
 		$this->federatedCalendarMapper->deleteById($this->getResourceId());
 	}
 
-	protected function getCalendarType(): int {
-		return CalDavBackend::CALENDAR_TYPE_FEDERATED;
+	public function createDirectory($name) {
+		throw new MethodNotAllowed('Creating nested collection is not allowed');
 	}
+
+	public function calendarQuery(array $filters) {
+		$uris = $this->caldavBackend->calendarQuery($this->federationInfo->getId(), $filters, $this->getCalendarType());
+		return $uris;
+	}
+
+	public function getChild($name) {
+		$obj = $this->caldavBackend->getCalendarObject($this->federationInfo->getId(), $name, $this->getCalendarType());
+
+		if (!$obj) {
+			throw new NotFound('Calendar object not found');
+		}
+		$obj['acl'] = $this->getChildACL();
+
+		return new FederatedCalendarObject($this, $obj);
+	}
+
+	public function getChildren() {
+		$objs = $this->caldavBackend->getCalendarObjects($this->federationInfo->getId(), $this->getCalendarType());
+		$children = [];
+		foreach ($objs as $obj) {
+			$obj['acl'] = $this->getChildACL();
+			$children[] = new FederatedCalendarObject($this, $obj);
+		}
+
+		return $children;
+	}
+
+	public function getMultipleChildren(array $paths) {
+		$objs = $this->caldavBackend->getMultipleCalendarObjects($this->federationInfo->getId(), $paths, $this->getCalendarType());
+		$children = [];
+		foreach ($objs as $obj) {
+			$obj['acl'] = $this->getChildACL();
+			$children[] = new FederatedCalendarObject($this, $obj);
+		}
+
+		return $children;
+	}
+
+	public function childExists($name) {
+		$obj = $this->caldavBackend->getCalendarObject($this->federationInfo->getId(), $name, $this->getCalendarType());
+		if (!$obj) {
+			return false;
+		} else {
+			return true;
+		}
+	}
+
+	public function createFile($name, $data = null) {
+		if (is_resource($data)) {
+			$data = stream_get_contents($data);
+		}
+
+		// Create on remote server first
+		$etag = $this->federatedCalendarService->createCalendarObject($this->federationInfo, $name, $data);
+
+		// Then store locally
+		$localEtag = $this->caldavBackend->createCalendarObject($this->federationInfo->getId(), $name, $data, $this->getCalendarType());
+
+		return $localEtag;
+	}
+
+	public function updateFile($name, $data = null) {
+		if (is_resource($data)) {
+			$data = stream_get_contents($data);
+		}
+
+		// Update remote calendar first
+		$etag = $this->federatedCalendarService->updateCalendarObject($this->federationInfo, $name, $data);
+
+		// Then update locally
+		return $this->caldavBackend->updateCalendarObject($this->federationInfo->getId(), $name, $data, $this->getCalendarType());
+	}
+
+	public function deleteFile($name) {
+		// Delete from remote server first
+		$this->federatedCalendarService->deleteCalendarObject($this->federationInfo, $name);
+
+		// Then delete locally
+		return $this->caldavBackend->deleteCalendarObject($this->federationInfo->getId(), $name, $this->getCalendarType());
+	}
+
 }

apps/dav/lib/CalDAV/Federation/FederatedCalendarEntity.php

@@ -94,8 +94,8 @@ class FederatedCalendarEntity extends Entity {
 			'{' . \Sabre\CalDAV\Plugin::NS_CALENDARSERVER . '}getctag' => $this->getSyncTokenForSabre(),
 			'{' . \Sabre\CalDAV\Plugin::NS_CALDAV . '}supported-calendar-component-set' => $this->getSupportedCalendarComponentSet(),
 			'{' . \OCA\DAV\DAV\Sharing\Plugin::NS_OWNCLOUD . '}owner-principal' => $this->getSharedByPrincipal(),
-			// TODO: implement read-write sharing
-			'{' . \OCA\DAV\DAV\Sharing\Plugin::NS_OWNCLOUD . '}read-only' => 1
+			'{' . \OCA\DAV\DAV\Sharing\Plugin::NS_OWNCLOUD . '}read-only' => ($this->getPermissions() & \OCP\Constants::PERMISSION_UPDATE) === 0 ? 1 : 0,
+			'{' . \OCA\DAV\DAV\Sharing\Plugin::NS_OWNCLOUD . '}permissions' => $this->getPermissions(),
 		];
 	}
 }

apps/dav/lib/CalDAV/Federation/FederatedCalendarFactory.php

@@ -9,34 +9,26 @@ declare(strict_types=1);
 
 namespace OCA\DAV\CalDAV\Federation;
 
-use OCA\DAV\AppInfo\Application;
 use OCA\DAV\CalDAV\CalDavBackend;
-use OCP\IConfig;
-use OCP\IL10N;
-use OCP\L10N\IFactory as IL10NFactory;
 use Psr\Log\LoggerInterface;
 
 class FederatedCalendarFactory {
-	private readonly IL10N $l10n;
 
 	public function __construct(
-		private readonly CalDavBackend $caldavBackend,
-		private readonly IConfig $config,
 		private readonly LoggerInterface $logger,
 		private readonly FederatedCalendarMapper $federatedCalendarMapper,
-		IL10NFactory $l10nFactory,
+		private readonly FederatedCalendarSyncService $federatedCalendarService,
+		private readonly CalDavBackend $caldavBackend,
 	) {
-		$this->l10n = $l10nFactory->get(Application::APP_ID);
 	}
 
 	public function createFederatedCalendar(array $calendarInfo): FederatedCalendar {
 		return new FederatedCalendar(
-			$this->caldavBackend,
-			$calendarInfo,
-			$this->l10n,
-			$this->config,
 			$this->logger,
 			$this->federatedCalendarMapper,
+			$this->federatedCalendarService,
+			$this->caldavBackend,
+			$calendarInfo,
 		);
 	}
 }

apps/dav/lib/CalDAV/Federation/FederatedCalendarImpl.php

@@ -51,8 +51,7 @@ class FederatedCalendarImpl implements ICalendar, ICalendarIsShared, ICalendarIs
 	}
 
 	public function getPermissions(): int {
-		// TODO: implement read-write sharing
-		return Constants::PERMISSION_READ;
+		return $this->calendarInfo['{http://owncloud.org/ns}permissions'] ?? Constants::PERMISSION_READ;
 	}
 
 	public function isDeleted(): bool {
@@ -64,7 +63,8 @@ class FederatedCalendarImpl implements ICalendar, ICalendarIsShared, ICalendarIs
 	}
 
 	public function isWritable(): bool {
-		return false;
+		$permissions = $this->getPermissions();
+		return ($permissions & Constants::PERMISSION_UPDATE) !== 0;
 	}
 
 	public function isEnabled(): bool {

apps/dav/lib/CalDAV/Federation/FederatedCalendarObject.php

@@ -0,0 +1,130 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\DAV\CalDAV\Federation;
+
+use Sabre\CalDAV\ICalendarObject;
+use Sabre\DAV\Exception\MethodNotAllowed;
+use Sabre\DAVACL\IACL;
+
+class FederatedCalendarObject implements ICalendarObject, IACL {
+
+	public function __construct(
+		protected FederatedCalendar $calendarObject,
+		protected $objectData,
+	) {
+	}
+
+	public function getName() {
+		return $this->objectData['uri'];
+	}
+
+	public function setName($name) {
+		throw new \Exception('Not implemented');
+	}
+
+	public function get() {
+		return $this->objectData['calendardata'];
+	}
+
+	public function put($calendarData) {
+
+		$etag = $this->calendarObject->updateFile($this->objectData['uri'], $calendarData);
+		$this->objectData['calendardata'] = $calendarData;
+		$this->objectData['etag'] = $etag;
+
+		return $etag;
+	}
+
+	/**
+	 * Deletes the calendar object.
+	 */
+	public function delete() {
+		$this->calendarObject->deleteFile($this->objectData['uri']);
+	}
+
+	/**
+	 * Returns the mime content-type.
+	 *
+	 * @return string
+	 */
+	public function getContentType() {
+		$mime = 'text/calendar; charset=utf-8';
+		if (isset($this->objectData['component']) && $this->objectData['component']) {
+			$mime .= '; component=' . $this->objectData['component'];
+		}
+
+		return $mime;
+	}
+
+	/**
+	 * Returns an ETag for this object.
+	 *
+	 * The ETag is an arbitrary string, but MUST be surrounded by double-quotes.
+	 *
+	 * @return string
+	 */
+	public function getETag() {
+		if (isset($this->objectData['etag'])) {
+			return $this->objectData['etag'];
+		} else {
+			return '"' . md5($this->get()) . '"';
+		}
+	}
+
+	/**
+	 * Returns the last modification date as a unix timestamp.
+	 *
+	 * @return int
+	 */
+	public function getLastModified() {
+		return $this->objectData['lastmodified'];
+	}
+
+	/**
+	 * Returns the size of this object in bytes.
+	 *
+	 * @return int
+	 */
+	public function getSize() {
+		if (array_key_exists('size', $this->objectData)) {
+			return $this->objectData['size'];
+		} else {
+			return strlen($this->get());
+		}
+	}
+
+	/**
+	 * Returns the owner principal.
+	 *
+	 * This must be a url to a principal, or null if there's no owner
+	 *
+	 * @return string|null
+	 */
+	public function getOwner() {
+		return $this->calendarObject->getPrincipalURI();
+	}
+
+	public function getGroup() {
+		return null;
+	}
+
+	public function getACL() {
+		return $this->calendarObject->getACL();
+	}
+
+	public function setACL(array $acl) {
+		throw new MethodNotAllowed('Changing ACLs on federated events is not allowed');
+	}
+
+	public function getSupportedPrivilegeSet() {
+		return null;
+	}
+
+}

apps/dav/lib/CalDAV/Federation/FederatedCalendarSyncService.php

@@ -9,20 +9,52 @@ declare(strict_types=1);
 
 namespace OCA\DAV\CalDAV\Federation;
 
-use OCA\DAV\CalDAV\SyncService as CalDavSyncService;
+use OCA\DAV\CalDAV\CalDavBackend;
+use OCA\DAV\Service\ASyncService;
+use OCP\AppFramework\Db\TTransactional;
+use OCP\AppFramework\Http;
 use OCP\Federation\ICloudIdManager;
+use OCP\Http\Client\IClientService;
+use OCP\IConfig;
+use OCP\IDBConnection;
 use Psr\Http\Client\ClientExceptionInterface;
 use Psr\Log\LoggerInterface;
 
-class FederatedCalendarSyncService {
+class FederatedCalendarSyncService extends ASyncService {
+	use TTransactional;
+
 	private const SYNC_TOKEN_PREFIX = 'http://sabre.io/ns/sync/';
 
 	public function __construct(
+		IClientService $clientService,
+		IConfig $config,
 		private readonly FederatedCalendarMapper $federatedCalendarMapper,
 		private readonly LoggerInterface $logger,
-		private readonly CalDavSyncService $syncService,
+		private readonly CalDavBackend $backend,
+		private readonly IDBConnection $dbConnection,
 		private readonly ICloudIdManager $cloudIdManager,
 	) {
+		parent::__construct($clientService, $config);
+	}
+
+	/**
+	 * Extract and encode credentials from a federated calendar entity.
+	 *
+	 * @return array{username: string, remoteUrl: string, token: string}
+	 */
+	private function getCredentials(FederatedCalendarEntity $calendar): array {
+		[,, $sharedWith] = explode('/', $calendar->getPrincipaluri());
+		$calDavUser = $this->cloudIdManager->getCloudId($sharedWith, null)->getId();
+
+		// Need to encode the cloud id as it might contain a colon which is not allowed in basic
+		// auth according to RFC 7617
+		$calDavUser = base64_encode($calDavUser);
+
+		return [
+			'username' => $calDavUser,
+			'remoteUrl' => $calendar->getRemoteUrl(),
+			'token' => $calendar->getToken(),
+		];
 	}
 
 	/**
@@ -31,29 +63,77 @@ class FederatedCalendarSyncService {
 	 * @throws ClientExceptionInterface If syncing the calendar fails.
 	 */
 	public function syncOne(FederatedCalendarEntity $calendar): int {
-		[,, $sharedWith] = explode('/', $calendar->getPrincipaluri());
-		$calDavUser = $this->cloudIdManager->getCloudId($sharedWith, null)->getId();
-		$remoteUrl = $calendar->getRemoteUrl();
+		$credentials = $this->getCredentials($calendar);
 		$syncToken = $calendar->getSyncTokenForSabre();
 
-		// Need to encode the cloud id as it might contain a colon which is not allowed in basic
-		// auth according to RFC 7617
-		$calDavUser = base64_encode($calDavUser);
+		try {
+			$response = $this->requestSyncReport(
+				$credentials['remoteUrl'],
+				$credentials['username'],
+				$credentials['token'],
+				$syncToken,
+			);
+		} catch (ClientExceptionInterface $ex) {
+			if ($ex->getCode() === Http::STATUS_UNAUTHORIZED) {
+				// Remote server revoked access to the calendar => remove it
+				$this->federatedCalendarMapper->delete($calendar);
+				$this->logger->error("Authorization failed, remove federated calendar: {$credentials['remoteUrl']}", [
+					'app' => 'dav',
+				]);
+				throw $ex;
+			}
+			$this->logger->error('Client exception:', ['app' => 'dav', 'exception' => $ex]);
+			throw $ex;
+		}
 
-		$syncResponse = $this->syncService->syncRemoteCalendar(
-			$remoteUrl,
-			$calDavUser,
-			$calendar->getToken(),
-			$syncToken,
-			$calendar,
-		);
+		// Process changes from remote
+		$downloadedEvents = 0;
+		foreach ($response['response'] as $resource => $status) {
+			$objectUri = basename($resource);
+			if (isset($status[200])) {
+				// Object created or updated
+				$absoluteUrl = $this->prepareUri($credentials['remoteUrl'], $resource);
+				$calendarData = $this->download($absoluteUrl, $credentials['username'], $credentials['token']);
+				$this->atomic(function () use ($calendar, $objectUri, $calendarData): void {
+					$existingObject = $this->backend->getCalendarObject(
+						$calendar->getId(),
+						$objectUri,
+						CalDavBackend::CALENDAR_TYPE_FEDERATED
+					);
+					if (!$existingObject) {
+						$this->backend->createCalendarObject(
+							$calendar->getId(),
+							$objectUri,
+							$calendarData,
+							CalDavBackend::CALENDAR_TYPE_FEDERATED
+						);
+					} else {
+						$this->backend->updateCalendarObject(
+							$calendar->getId(),
+							$objectUri,
+							$calendarData,
+							CalDavBackend::CALENDAR_TYPE_FEDERATED
+						);
+					}
+				}, $this->dbConnection);
+				$downloadedEvents++;
+			} else {
+				// Object deleted
+				$this->backend->deleteCalendarObject(
+					$calendar->getId(),
+					$objectUri,
+					CalDavBackend::CALENDAR_TYPE_FEDERATED,
+					true
+				);
+			}
+		}
 
-		$newSyncToken = $syncResponse->getSyncToken();
+		$newSyncToken = $response['token'];
 
 		// Check sync token format and extract the actual sync token integer
 		$matches = [];
 		if (!preg_match('/^http:\/\/sabre\.io\/ns\/sync\/([0-9]+)$/', $newSyncToken, $matches)) {
-			$this->logger->error("Failed to sync federated calendar at $remoteUrl: New sync token has unexpected format: $newSyncToken", [
+			$this->logger->error("Failed to sync federated calendar at {$credentials['remoteUrl']}: New sync token has unexpected format: $newSyncToken", [
 				'calendar' => $calendar->toCalendarInfo(),
 				'newSyncToken' => $newSyncToken,
 			]);
@@ -67,10 +147,58 @@ class FederatedCalendarSyncService {
 				$newSyncToken,
 			);
 		} else {
-			$this->logger->debug("Sync Token for $remoteUrl unchanged from previous sync");
+			$this->logger->debug("Sync Token for {$credentials['remoteUrl']} unchanged from previous sync");
 			$this->federatedCalendarMapper->updateSyncTime($calendar->getId());
 		}
 
-		return $syncResponse->getDownloadedEvents();
+		return $downloadedEvents;
+	}
+
+	/**
+	 * Create a calendar object on the remote server.
+	 *
+	 * @throws ClientExceptionInterface If the remote request fails.
+	 */
+	public function createCalendarObject(FederatedCalendarEntity $calendar, string $name, string $data): string {
+		$credentials = $this->getCredentials($calendar);
+		$objectUrl = $this->prepareUri($credentials['remoteUrl'], $name);
+
+		return $this->requestPut(
+			$objectUrl,
+			$credentials['username'],
+			$credentials['token'],
+			$data,
+			'text/calendar; charset=utf-8'
+		);
+	}
+
+	/**
+	 * Update a calendar object on the remote server.
+	 *
+	 * @throws ClientExceptionInterface If the remote request fails.
+	 */
+	public function updateCalendarObject(FederatedCalendarEntity $calendar, string $name, string $data): string {
+		$credentials = $this->getCredentials($calendar);
+		$objectUrl = $this->prepareUri($credentials['remoteUrl'], $name);
+
+		return $this->requestPut(
+			$objectUrl,
+			$credentials['username'],
+			$credentials['token'],
+			$data,
+			'text/calendar; charset=utf-8'
+		);
+	}
+
+	/**
+	 * Delete a calendar object on the remote server.
+	 *
+	 * @throws ClientExceptionInterface If the remote request fails.
+	 */
+	public function deleteCalendarObject(FederatedCalendarEntity $calendar, string $name): void {
+		$credentials = $this->getCredentials($calendar);
+		$objectUrl = $this->prepareUri($credentials['remoteUrl'], $name);
+
+		$this->requestDelete($objectUrl, $credentials['username'], $credentials['token']);
 	}
 }

apps/dav/lib/CalDAV/Schedule/Plugin.php

@@ -12,6 +12,7 @@ use OCA\DAV\CalDAV\Calendar;
 use OCA\DAV\CalDAV\CalendarHome;
 use OCA\DAV\CalDAV\CalendarObject;
 use OCA\DAV\CalDAV\DefaultCalendarValidator;
+use OCA\DAV\CalDAV\Federation\FederatedCalendar;
 use OCA\DAV\CalDAV\TipBroker;
 use OCP\IConfig;
 use Psr\Log\LoggerInterface;
@@ -172,8 +173,15 @@ class Plugin extends \Sabre\CalDAV\Schedule\Plugin {
 				return;
 			}
 
-			/** @var Calendar $calendarNode */
+			/** @var Calendar&ICalendar $calendarNode */
 			$calendarNode = $this->server->tree->getNodeForPath($calendarPath);
+
+			// abort if calendar is federated
+			if ($calendarNode instanceof FederatedCalendar) {
+				$this->logger->debug('Not processing scheduling for federated calendar at path: ' . $calendarPath);
+				return;
+			}
+
 			// extract addresses for owner
 			$addresses = $this->getAddressesForPrincipal($calendarNode->getOwner());
 			// determine if request is from a sharee

apps/dav/lib/Service/ASyncService.php

@@ -191,4 +191,70 @@ abstract class ASyncService {
 			rtrim($responseUri, '/'),
 		);
 	}
+
+	/**
+	 * Push data to the remote server via HTTP PUT.
+	 * Used for creating or updating CalDAV/CardDAV objects.
+	 *
+	 * @param string $url The absolute URL to PUT to
+	 * @param string $username The username for authentication
+	 * @param string $token The authentication token/password
+	 * @param string $data The data to upload
+	 * @param string $contentType The Content-Type header (e.g., 'text/calendar' or 'text/vcard')
+	 *
+	 * @return string The ETag returned by the server
+	 */
+	protected function requestPut(
+		string $url,
+		string $username,
+		string $token,
+		string $data,
+		string $contentType = 'text/calendar; charset=utf-8',
+	): string {
+		$client = $this->getClient();
+
+		$options = [
+			'auth' => [$username, $token],
+			'body' => $data,
+			'headers' => [
+				'Content-Type' => $contentType,
+			],
+			'verify' => !$this->config->getSystemValue(
+				'sharing.federation.allowSelfSignedCertificates',
+				false,
+			),
+		];
+
+		$response = $client->put($url, $options);
+
+		// Extract and return the ETag from the response
+		$etag = $response->getHeader('ETag');
+		return is_array($etag) ? $etag[0] : (string)$etag;
+	}
+
+	/**
+	 * Delete a resource from the remote server via HTTP DELETE.
+	 * Used for deleting CalDAV/CardDAV objects.
+	 *
+	 * @param string $url The absolute URL to DELETE
+	 * @param string $username The username for authentication
+	 * @param string $token The authentication token/password
+	 */
+	protected function requestDelete(
+		string $url,
+		string $username,
+		string $token,
+	): void {
+		$client = $this->getClient();
+
+		$options = [
+			'auth' => [$username, $token],
+			'verify' => !$this->config->getSystemValue(
+				'sharing.federation.allowSelfSignedCertificates',
+				false,
+			),
+		];
+
+		$client->delete($url, $options);
+	}
 }

apps/dav/tests/unit/CalDAV/Federation/CalendarFederationProviderTest.php

@@ -92,11 +92,12 @@ class CalendarFederationProviderTest extends TestCase {
 			->willReturn(true);
 
 		$this->federatedCalendarMapper->expects(self::once())
-			->method('deleteByUri')
+			->method('findByUri')
 			->with(
 				'principals/users/sharee1',
 				'ae4b8ab904076fff2b955ea21b1a0d92',
-			);
+			)
+			->willReturn(null);
 
 		$this->federatedCalendarMapper->expects(self::once())
 			->method('insert')
@@ -123,6 +124,68 @@ class CalendarFederationProviderTest extends TestCase {
 		$this->assertEquals(10, $this->calendarFederationProvider->shareReceived($share));
 	}
 
+	public function testShareReceivedWithExistingCalendar(): void {
+		$share = $this->createMock(ICloudFederationShare::class);
+		$share->method('getShareType')
+			->willReturn('user');
+		$share->method('getProtocol')
+			->willReturn([
+				'version' => 'v1',
+				'url' => 'https://nextcloud.remote/remote.php/dav/remote-calendars/abcdef123/cal1_shared_by_user1',
+				'displayName' => 'Calendar 1',
+				'color' => '#ff0000',
+				'access' => 3,
+				'components' => 'VEVENT,VTODO',
+			]);
+		$share->method('getShareWith')
+			->willReturn('sharee1');
+		$share->method('getShareSecret')
+			->willReturn('new-token');
+		$share->method('getSharedBy')
+			->willReturn('user1@nextcloud.remote');
+		$share->method('getSharedByDisplayName')
+			->willReturn('User 1');
+
+		$this->calendarFederationConfig->expects(self::once())
+			->method('isFederationEnabled')
+			->willReturn(true);
+
+		$existingCalendar = new FederatedCalendarEntity();
+		$existingCalendar->setId(10);
+		$existingCalendar->setPrincipaluri('principals/users/sharee1');
+		$existingCalendar->setUri('ae4b8ab904076fff2b955ea21b1a0d92');
+		$existingCalendar->setRemoteUrl('https://nextcloud.remote/remote.php/dav/remote-calendars/abcdef123/cal1_shared_by_user1');
+		$existingCalendar->setToken('old-token');
+		$existingCalendar->setPermissions(1);
+		$existingCalendar->setComponents('VEVENT');
+
+		$this->federatedCalendarMapper->expects(self::once())
+			->method('findByUri')
+			->with(
+				'principals/users/sharee1',
+				'ae4b8ab904076fff2b955ea21b1a0d92',
+			)
+			->willReturn($existingCalendar);
+
+		$this->federatedCalendarMapper->expects(self::never())
+			->method('insert');
+
+		$this->federatedCalendarMapper->expects(self::once())
+			->method('update')
+			->willReturnCallback(function (FederatedCalendarEntity $calendar) {
+				$this->assertEquals('new-token', $calendar->getToken());
+				$this->assertEquals(1, $calendar->getPermissions());
+				$this->assertEquals('VEVENT,VTODO', $calendar->getComponents());
+				return $calendar;
+			});
+
+		$this->jobList->expects(self::once())
+			->method('add')
+			->with(FederatedCalendarSyncJob::class, ['id' => 10]);
+
+		$this->assertEquals(10, $this->calendarFederationProvider->shareReceived($share));
+	}
+
 	public function testShareReceivedWithInvalidProtocolVersion(): void {
 		$share = $this->createMock(ICloudFederationShare::class);
 		$share->method('getShareType')
@@ -270,7 +333,7 @@ class CalendarFederationProviderTest extends TestCase {
 		$this->calendarFederationProvider->shareReceived($share);
 	}
 
-	public function testShareReceivedWithUnsupportedAccess(): void {
+	public function testShareReceivedWithReadWriteAccess(): void {
 		$share = $this->createMock(ICloudFederationShare::class);
 		$share->method('getShareType')
 			->willReturn('user');
@@ -296,6 +359,65 @@ class CalendarFederationProviderTest extends TestCase {
 			->method('isFederationEnabled')
 			->willReturn(true);
 
+		$this->federatedCalendarMapper->expects(self::once())
+			->method('findByUri')
+			->with(
+				'principals/users/sharee1',
+				'ae4b8ab904076fff2b955ea21b1a0d92',
+			)
+			->willReturn(null);
+
+		$this->federatedCalendarMapper->expects(self::once())
+			->method('insert')
+			->willReturnCallback(function (FederatedCalendarEntity $calendar) {
+				$this->assertEquals('principals/users/sharee1', $calendar->getPrincipaluri());
+				$this->assertEquals('ae4b8ab904076fff2b955ea21b1a0d92', $calendar->getUri());
+				$this->assertEquals('https://nextcloud.remote/remote.php/dav/remote-calendars/abcdef123/cal1_shared_by_user1', $calendar->getRemoteUrl());
+				$this->assertEquals('Calendar 1', $calendar->getDisplayName());
+				$this->assertEquals('#ff0000', $calendar->getColor());
+				$this->assertEquals('token', $calendar->getToken());
+				$this->assertEquals('user1@nextcloud.remote', $calendar->getSharedBy());
+				$this->assertEquals('User 1', $calendar->getSharedByDisplayName());
+				$this->assertEquals(15, $calendar->getPermissions()); // READ | CREATE | UPDATE | DELETE
+				$this->assertEquals('VEVENT,VTODO', $calendar->getComponents());
+
+				$calendar->setId(10);
+				return $calendar;
+			});
+
+		$this->jobList->expects(self::once())
+			->method('add')
+			->with(FederatedCalendarSyncJob::class, ['id' => 10]);
+
+		$this->assertEquals(10, $this->calendarFederationProvider->shareReceived($share));
+	}
+
+	public function testShareReceivedWithUnsupportedAccess(): void {
+		$share = $this->createMock(ICloudFederationShare::class);
+		$share->method('getShareType')
+			->willReturn('user');
+		$share->method('getProtocol')
+			->willReturn([
+				'version' => 'v1',
+				'url' => 'https://nextcloud.remote/remote.php/dav/remote-calendars/abcdef123/cal1_shared_by_user1',
+				'displayName' => 'Calendar 1',
+				'color' => '#ff0000',
+				'access' => 999, // Invalid access value
+				'components' => 'VEVENT,VTODO',
+			]);
+		$share->method('getShareWith')
+			->willReturn('sharee1');
+		$share->method('getShareSecret')
+			->willReturn('token');
+		$share->method('getSharedBy')
+			->willReturn('user1@nextcloud.remote');
+		$share->method('getSharedByDisplayName')
+			->willReturn('User 1');
+
+		$this->calendarFederationConfig->expects(self::once())
+			->method('isFederationEnabled')
+			->willReturn(true);
+
 		$this->federatedCalendarMapper->expects(self::never())
 			->method('insert');
 		$this->jobList->expects(self::never())

apps/dav/tests/unit/CalDAV/Federation/FederatedCalendarSyncServiceTest.php

@@ -9,13 +9,17 @@ declare(strict_types=1);
 
 namespace OCA\DAV\Tests\unit\CalDAV\Federation;
 
+use OCA\DAV\CalDAV\CalDavBackend;
 use OCA\DAV\CalDAV\Federation\FederatedCalendarEntity;
 use OCA\DAV\CalDAV\Federation\FederatedCalendarMapper;
 use OCA\DAV\CalDAV\Federation\FederatedCalendarSyncService;
-use OCA\DAV\CalDAV\SyncService as CalDavSyncService;
-use OCA\DAV\CalDAV\SyncServiceResult;
 use OCP\Federation\ICloudId;
 use OCP\Federation\ICloudIdManager;
+use OCP\Http\Client\IClient;
+use OCP\Http\Client\IClientService;
+use OCP\Http\Client\IResponse;
+use OCP\IConfig;
+use OCP\IDBConnection;
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\MockObject\MockObject;
 use Psr\Log\LoggerInterface;
@@ -26,21 +30,30 @@ class FederatedCalendarSyncServiceTest extends TestCase {
 
 	private FederatedCalendarMapper&MockObject $federatedCalendarMapper;
 	private LoggerInterface&MockObject $logger;
-	private CalDavSyncService&MockObject $calDavSyncService;
+	private CalDavBackend&MockObject $backend;
+	private IDBConnection&MockObject $dbConnection;
 	private ICloudIdManager&MockObject $cloudIdManager;
+	private IClientService&MockObject $clientService;
+	private IConfig&MockObject $config;
 
 	protected function setUp(): void {
 		parent::setUp();
 
 		$this->federatedCalendarMapper = $this->createMock(FederatedCalendarMapper::class);
 		$this->logger = $this->createMock(LoggerInterface::class);
-		$this->calDavSyncService = $this->createMock(CalDavSyncService::class);
+		$this->backend = $this->createMock(CalDavBackend::class);
+		$this->dbConnection = $this->createMock(IDBConnection::class);
 		$this->cloudIdManager = $this->createMock(ICloudIdManager::class);
+		$this->clientService = $this->createMock(IClientService::class);
+		$this->config = $this->createMock(IConfig::class);
 
 		$this->federatedCalendarSyncService = new FederatedCalendarSyncService(
+			$this->clientService,
+			$this->config,
 			$this->federatedCalendarMapper,
 			$this->logger,
-			$this->calDavSyncService,
+			$this->backend,
+			$this->dbConnection,
 			$this->cloudIdManager,
 		);
 	}
@@ -61,16 +74,24 @@ class FederatedCalendarSyncServiceTest extends TestCase {
 			->with('user1')
 			->willReturn($cloudId);
 
-		$this->calDavSyncService->expects(self::once())
-			->method('syncRemoteCalendar')
-			->with(
-				'https://remote.tld/remote.php/dav/remote-calendars/abcdef123/cal1_shared_by_user2',
-				'dXNlcjFAbmV4dGNsb3VkLnRlc3Rpbmc=',
-				'token',
-				'http://sabre.io/ns/sync/100',
-				$calendar,
-			)
-			->willReturn(new SyncServiceResult('http://sabre.io/ns/sync/101', 10));
+		// Mock HTTP client for sync report
+		$client = $this->createMock(IClient::class);
+		$response = $this->createMock(IResponse::class);
+		$response->method('getBody')
+			->willReturn('<?xml version="1.0"?><d:multistatus xmlns:d="DAV:"><d:sync-token>http://sabre.io/ns/sync/101</d:sync-token></d:multistatus>');
+
+		$client->expects(self::once())
+			->method('request')
+			->with('REPORT', 'https://remote.tld/remote.php/dav/remote-calendars/abcdef123/cal1_shared_by_user2', self::anything())
+			->willReturn($response);
+
+		$this->clientService->method('newClient')
+			->willReturn($client);
+
+		$this->config->method('getSystemValueInt')
+			->willReturn(30);
+		$this->config->method('getSystemValue')
+			->willReturn(false);
 
 		$this->federatedCalendarMapper->expects(self::once())
 			->method('updateSyncTokenAndTime')
@@ -78,7 +99,7 @@ class FederatedCalendarSyncServiceTest extends TestCase {
 		$this->federatedCalendarMapper->expects(self::never())
 			->method('updateSyncTime');
 
-		$this->assertEquals(10, $this->federatedCalendarSyncService->syncOne($calendar));
+		$this->assertEquals(0, $this->federatedCalendarSyncService->syncOne($calendar));
 	}
 
 	public function testSyncOneUnchanged(): void {
@@ -97,16 +118,24 @@ class FederatedCalendarSyncServiceTest extends TestCase {
 			->with('user1')
 			->willReturn($cloudId);
 
-		$this->calDavSyncService->expects(self::once())
-			->method('syncRemoteCalendar')
-			->with(
-				'https://remote.tld/remote.php/dav/remote-calendars/abcdef123/cal1_shared_by_user2',
-				'dXNlcjFAbmV4dGNsb3VkLnRlc3Rpbmc=',
-				'token',
-				'http://sabre.io/ns/sync/100',
-				$calendar,
-			)
-			->willReturn(new SyncServiceResult('http://sabre.io/ns/sync/100', 0));
+		// Mock HTTP client for sync report
+		$client = $this->createMock(IClient::class);
+		$response = $this->createMock(IResponse::class);
+		$response->method('getBody')
+			->willReturn('<?xml version="1.0"?><d:multistatus xmlns:d="DAV:"><d:sync-token>http://sabre.io/ns/sync/100</d:sync-token></d:multistatus>');
+
+		$client->expects(self::once())
+			->method('request')
+			->with('REPORT', 'https://remote.tld/remote.php/dav/remote-calendars/abcdef123/cal1_shared_by_user2', self::anything())
+			->willReturn($response);
+
+		$this->clientService->method('newClient')
+			->willReturn($client);
+
+		$this->config->method('getSystemValueInt')
+			->willReturn(30);
+		$this->config->method('getSystemValue')
+			->willReturn(false);
 
 		$this->federatedCalendarMapper->expects(self::never())
 			->method('updateSyncTokenAndTime');
@@ -143,16 +172,24 @@ class FederatedCalendarSyncServiceTest extends TestCase {
 			->with('user1')
 			->willReturn($cloudId);
 
-		$this->calDavSyncService->expects(self::once())
-			->method('syncRemoteCalendar')
-			->with(
-				'https://remote.tld/remote.php/dav/remote-calendars/abcdef123/cal1_shared_by_user2',
-				'dXNlcjFAbmV4dGNsb3VkLnRlc3Rpbmc=',
-				'token',
-				'http://sabre.io/ns/sync/100',
-				$calendar,
-			)
-			->willReturn(new SyncServiceResult($syncToken, 10));
+		// Mock HTTP client for sync report with unexpected token format
+		$client = $this->createMock(IClient::class);
+		$response = $this->createMock(IResponse::class);
+		$response->method('getBody')
+			->willReturn('<?xml version="1.0"?><d:multistatus xmlns:d="DAV:"><d:sync-token>' . $syncToken . '</d:sync-token></d:multistatus>');
+
+		$client->expects(self::once())
+			->method('request')
+			->with('REPORT', 'https://remote.tld/remote.php/dav/remote-calendars/abcdef123/cal1_shared_by_user2', self::anything())
+			->willReturn($response);
+
+		$this->clientService->method('newClient')
+			->willReturn($client);
+
+		$this->config->method('getSystemValueInt')
+			->willReturn(30);
+		$this->config->method('getSystemValue')
+			->willReturn(false);
 
 		$this->federatedCalendarMapper->expects(self::never())
 			->method('updateSyncTokenAndTime');

apps/dav/tests/unit/CalDAV/Federation/FederatedCalendarTest.php

@@ -0,0 +1,408 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\DAV\Tests\unit\CalDAV\Federation;
+
+use OCA\DAV\CalDAV\Federation\FederatedCalendar;
+use OCA\DAV\CalDAV\Federation\FederatedCalendarEntity;
+use OCA\DAV\CalDAV\Federation\FederatedCalendarMapper;
+use OCA\DAV\CalDAV\Federation\FederatedCalendarObject;
+use OCA\DAV\CalDAV\Federation\FederatedCalendarSyncService;
+use OCP\Constants;
+use PHPUnit\Framework\MockObject\MockObject;
+use Psr\Log\LoggerInterface;
+use Sabre\CalDAV\Backend\BackendInterface;
+use Sabre\DAV\Exception\MethodNotAllowed;
+use Sabre\DAV\Exception\NotFound;
+use Sabre\DAV\PropPatch;
+use Test\TestCase;
+
+class FederatedCalendarTest extends TestCase {
+	private FederatedCalendar $federatedCalendar;
+
+	private LoggerInterface&MockObject $logger;
+	private FederatedCalendarMapper&MockObject $federatedCalendarMapper;
+	private FederatedCalendarSyncService&MockObject $federatedCalendarService;
+	private BackendInterface&MockObject $caldavBackend;
+	private FederatedCalendarEntity $federationInfo;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->logger = $this->createMock(LoggerInterface::class);
+		$this->federatedCalendarMapper = $this->createMock(FederatedCalendarMapper::class);
+		$this->federatedCalendarService = $this->createMock(FederatedCalendarSyncService::class);
+		$this->caldavBackend = $this->createMock(BackendInterface::class);
+
+		$this->federationInfo = new FederatedCalendarEntity();
+		$this->federationInfo->setId(10);
+		$this->federationInfo->setPrincipaluri('principals/users/user1');
+		$this->federationInfo->setUri('calendar-uri');
+		$this->federationInfo->setDisplayName('Federated Calendar');
+		$this->federationInfo->setColor('#ff0000');
+		$this->federationInfo->setSharedBy('user2@nextcloud.remote');
+		$this->federationInfo->setSharedByDisplayName('User 2');
+		$this->federationInfo->setPermissions(Constants::PERMISSION_READ);
+		$this->federationInfo->setLastSync(1234567890);
+
+		$this->federatedCalendarMapper->method('findByUri')
+			->with('principals/users/user1', 'calendar-uri')
+			->willReturn($this->federationInfo);
+
+		$calendarInfo = [
+			'principaluri' => 'principals/users/user1',
+			'id' => 10,
+			'uri' => 'calendar-uri',
+		];
+
+		$this->federatedCalendar = new FederatedCalendar(
+			$this->logger,
+			$this->federatedCalendarMapper,
+			$this->federatedCalendarService,
+			$this->caldavBackend,
+			$calendarInfo,
+		);
+	}
+
+	public function testGetResourceId(): void {
+		$this->assertEquals(10, $this->federatedCalendar->getResourceId());
+	}
+
+	public function testGetName(): void {
+		$this->assertEquals('calendar-uri', $this->federatedCalendar->getName());
+	}
+
+	public function testSetName(): void {
+		$this->expectException(MethodNotAllowed::class);
+		$this->expectExceptionMessage('Renaming federated calendars is not allowed');
+		$this->federatedCalendar->setName('new-name');
+	}
+
+	public function testGetPrincipalURI(): void {
+		$this->assertEquals('principals/users/user1', $this->federatedCalendar->getPrincipalURI());
+	}
+
+	public function testGetOwner(): void {
+		$expected = 'principals/remote-users/' . base64_encode('user2@nextcloud.remote');
+		$this->assertEquals($expected, $this->federatedCalendar->getOwner());
+	}
+
+	public function testGetGroup(): void {
+		$this->assertNull($this->federatedCalendar->getGroup());
+	}
+
+	public function testGetACLWithReadOnlyPermissions(): void {
+		$this->federationInfo->setPermissions(Constants::PERMISSION_READ);
+
+		$acl = $this->federatedCalendar->getACL();
+
+		$this->assertCount(3, $acl);
+		// Check basic read permissions
+		$this->assertEquals('{DAV:}read', $acl[0]['privilege']);
+		$this->assertTrue($acl[0]['protected']);
+		$this->assertEquals('{DAV:}read-acl', $acl[1]['privilege']);
+		$this->assertTrue($acl[1]['protected']);
+		$this->assertEquals('{DAV:}write-properties', $acl[2]['privilege']);
+		$this->assertTrue($acl[2]['protected']);
+	}
+
+	public function testGetACLWithCreatePermission(): void {
+		$this->federationInfo->setPermissions(Constants::PERMISSION_READ | Constants::PERMISSION_CREATE);
+
+		$acl = $this->federatedCalendar->getACL();
+
+		$this->assertCount(4, $acl);
+		// Check that create permission is added
+		$privileges = array_column($acl, 'privilege');
+		$this->assertContains('{DAV:}bind', $privileges);
+	}
+
+	public function testGetACLWithUpdatePermission(): void {
+		$this->federationInfo->setPermissions(Constants::PERMISSION_READ | Constants::PERMISSION_UPDATE);
+
+		$acl = $this->federatedCalendar->getACL();
+
+		$this->assertCount(4, $acl);
+		// Check that update permission is added (write-content, not write-properties which is already in base ACL)
+		$privileges = array_column($acl, 'privilege');
+		$this->assertContains('{DAV:}write-content', $privileges);
+	}
+
+	public function testGetACLWithDeletePermission(): void {
+		$this->federationInfo->setPermissions(Constants::PERMISSION_READ | Constants::PERMISSION_DELETE);
+
+		$acl = $this->federatedCalendar->getACL();
+
+		$this->assertCount(4, $acl);
+		// Check that delete permission is added
+		$privileges = array_column($acl, 'privilege');
+		$this->assertContains('{DAV:}unbind', $privileges);
+	}
+
+	public function testGetACLWithAllPermissions(): void {
+		$this->federationInfo->setPermissions(
+			Constants::PERMISSION_READ
+			| Constants::PERMISSION_CREATE
+			| Constants::PERMISSION_UPDATE
+			| Constants::PERMISSION_DELETE
+		);
+
+		$acl = $this->federatedCalendar->getACL();
+
+		$this->assertCount(6, $acl);
+		$privileges = array_column($acl, 'privilege');
+		$this->assertContains('{DAV:}read', $privileges);
+		$this->assertContains('{DAV:}bind', $privileges);
+		$this->assertContains('{DAV:}write-content', $privileges);
+		$this->assertContains('{DAV:}write-properties', $privileges);
+		$this->assertContains('{DAV:}unbind', $privileges);
+	}
+
+	public function testSetACL(): void {
+		$this->expectException(MethodNotAllowed::class);
+		$this->expectExceptionMessage('Changing ACLs on federated calendars is not allowed');
+		$this->federatedCalendar->setACL([]);
+	}
+
+	public function testGetSupportedPrivilegeSet(): void {
+		$this->assertNull($this->federatedCalendar->getSupportedPrivilegeSet());
+	}
+
+	public function testGetProperties(): void {
+		$properties = $this->federatedCalendar->getProperties([
+			'{DAV:}displayname',
+			'{http://apple.com/ns/ical/}calendar-color',
+		]);
+
+		$this->assertEquals('Federated Calendar', $properties['{DAV:}displayname']);
+		$this->assertEquals('#ff0000', $properties['{http://apple.com/ns/ical/}calendar-color']);
+	}
+
+	public function testPropPatchWithDisplayName(): void {
+		$propPatch = $this->createMock(PropPatch::class);
+		$propPatch->method('getMutations')
+			->willReturn([
+				'{DAV:}displayname' => 'New Calendar Name',
+			]);
+
+		$this->federatedCalendarMapper->expects(self::once())
+			->method('update')
+			->willReturnCallback(function (FederatedCalendarEntity $entity) {
+				$this->assertEquals('New Calendar Name', $entity->getDisplayName());
+				return $entity;
+			});
+
+		$propPatch->expects(self::once())
+			->method('setResultCode')
+			->with('{DAV:}displayname', 200);
+
+		$this->federatedCalendar->propPatch($propPatch);
+	}
+
+	public function testPropPatchWithColor(): void {
+		$propPatch = $this->createMock(PropPatch::class);
+		$propPatch->method('getMutations')
+			->willReturn([
+				'{http://apple.com/ns/ical/}calendar-color' => '#00ff00',
+			]);
+
+		$this->federatedCalendarMapper->expects(self::once())
+			->method('update')
+			->willReturnCallback(function (FederatedCalendarEntity $entity) {
+				$this->assertEquals('#00ff00', $entity->getColor());
+				return $entity;
+			});
+
+		$propPatch->expects(self::once())
+			->method('setResultCode')
+			->with('{http://apple.com/ns/ical/}calendar-color', 200);
+
+		$this->federatedCalendar->propPatch($propPatch);
+	}
+
+	public function testPropPatchWithNoMutations(): void {
+		$propPatch = $this->createMock(PropPatch::class);
+		$propPatch->method('getMutations')
+			->willReturn([]);
+
+		$this->federatedCalendarMapper->expects(self::never())
+			->method('update');
+
+		$propPatch->expects(self::never())
+			->method('handle');
+
+		$this->federatedCalendar->propPatch($propPatch);
+	}
+
+	public function testGetChildACL(): void {
+		$this->assertEquals($this->federatedCalendar->getACL(), $this->federatedCalendar->getChildACL());
+	}
+
+	public function testGetLastModified(): void {
+		$this->assertEquals(1234567890, $this->federatedCalendar->getLastModified());
+	}
+
+	public function testDelete(): void {
+		$this->federatedCalendarMapper->expects(self::once())
+			->method('deleteById')
+			->with(10);
+
+		$this->federatedCalendar->delete();
+	}
+
+	public function testCreateDirectory(): void {
+		$this->expectException(MethodNotAllowed::class);
+		$this->expectExceptionMessage('Creating nested collection is not allowed');
+		$this->federatedCalendar->createDirectory('test');
+	}
+
+	public function testCalendarQuery(): void {
+		$filters = ['comp-filter' => ['name' => 'VEVENT']];
+		$expectedUris = ['event1.ics', 'event2.ics'];
+
+		$this->caldavBackend->expects(self::once())
+			->method('calendarQuery')
+			->with(10, $filters, 2) // 2 is CALENDAR_TYPE_FEDERATED
+			->willReturn($expectedUris);
+
+		$result = $this->federatedCalendar->calendarQuery($filters);
+		$this->assertEquals($expectedUris, $result);
+	}
+
+	public function testGetChild(): void {
+		$objectData = [
+			'id' => 1,
+			'uri' => 'event1.ics',
+			'calendardata' => 'BEGIN:VCALENDAR...',
+		];
+
+		$this->caldavBackend->expects(self::once())
+			->method('getCalendarObject')
+			->with(10, 'event1.ics', 2) // 2 is CALENDAR_TYPE_FEDERATED
+			->willReturn($objectData);
+
+		$child = $this->federatedCalendar->getChild('event1.ics');
+		$this->assertInstanceOf(FederatedCalendarObject::class, $child);
+	}
+
+	public function testGetChildNotFound(): void {
+		$this->caldavBackend->expects(self::once())
+			->method('getCalendarObject')
+			->with(10, 'nonexistent.ics', 2)
+			->willReturn(null);
+
+		$this->expectException(NotFound::class);
+		$this->federatedCalendar->getChild('nonexistent.ics');
+	}
+
+	public function testGetChildren(): void {
+		$objects = [
+			['id' => 1, 'uri' => 'event1.ics', 'calendardata' => 'BEGIN:VCALENDAR...'],
+			['id' => 2, 'uri' => 'event2.ics', 'calendardata' => 'BEGIN:VCALENDAR...'],
+		];
+
+		$this->caldavBackend->expects(self::once())
+			->method('getCalendarObjects')
+			->with(10, 2) // 2 is CALENDAR_TYPE_FEDERATED
+			->willReturn($objects);
+
+		$children = $this->federatedCalendar->getChildren();
+		$this->assertCount(2, $children);
+		$this->assertInstanceOf(FederatedCalendarObject::class, $children[0]);
+		$this->assertInstanceOf(FederatedCalendarObject::class, $children[1]);
+	}
+
+	public function testGetMultipleChildren(): void {
+		$paths = ['event1.ics', 'event2.ics'];
+		$objects = [
+			['id' => 1, 'uri' => 'event1.ics', 'calendardata' => 'BEGIN:VCALENDAR...'],
+			['id' => 2, 'uri' => 'event2.ics', 'calendardata' => 'BEGIN:VCALENDAR...'],
+		];
+
+		$this->caldavBackend->expects(self::once())
+			->method('getMultipleCalendarObjects')
+			->with(10, $paths, 2) // 2 is CALENDAR_TYPE_FEDERATED
+			->willReturn($objects);
+
+		$children = $this->federatedCalendar->getMultipleChildren($paths);
+		$this->assertCount(2, $children);
+		$this->assertInstanceOf(FederatedCalendarObject::class, $children[0]);
+		$this->assertInstanceOf(FederatedCalendarObject::class, $children[1]);
+	}
+
+	public function testChildExists(): void {
+		$this->caldavBackend->expects(self::once())
+			->method('getCalendarObject')
+			->with(10, 'event1.ics', 2)
+			->willReturn(['id' => 1, 'uri' => 'event1.ics']);
+
+		$result = $this->federatedCalendar->childExists('event1.ics');
+		$this->assertTrue($result);
+	}
+
+	public function testChildNotExists(): void {
+		$this->caldavBackend->expects(self::once())
+			->method('getCalendarObject')
+			->with(10, 'nonexistent.ics', 2)
+			->willReturn(null);
+
+		$result = $this->federatedCalendar->childExists('nonexistent.ics');
+		$this->assertFalse($result);
+	}
+
+	public function testCreateFile(): void {
+		$calendarData = 'BEGIN:VCALENDAR...END:VCALENDAR';
+		$remoteEtag = '"remote-etag-123"';
+		$localEtag = '"local-etag-456"';
+
+		$this->federatedCalendarService->expects(self::once())
+			->method('createCalendarObject')
+			->with($this->federationInfo, 'event1.ics', $calendarData)
+			->willReturn($remoteEtag);
+
+		$this->caldavBackend->expects(self::once())
+			->method('createCalendarObject')
+			->with(10, 'event1.ics', $calendarData, 2)
+			->willReturn($localEtag);
+
+		$result = $this->federatedCalendar->createFile('event1.ics', $calendarData);
+		$this->assertEquals($localEtag, $result);
+	}
+
+	public function testUpdateFile(): void {
+		$calendarData = 'BEGIN:VCALENDAR...UPDATED...END:VCALENDAR';
+		$remoteEtag = '"remote-etag-updated"';
+		$localEtag = '"local-etag-updated"';
+
+		$this->federatedCalendarService->expects(self::once())
+			->method('updateCalendarObject')
+			->with($this->federationInfo, 'event1.ics', $calendarData)
+			->willReturn($remoteEtag);
+
+		$this->caldavBackend->expects(self::once())
+			->method('updateCalendarObject')
+			->with(10, 'event1.ics', $calendarData, 2)
+			->willReturn($localEtag);
+
+		$result = $this->federatedCalendar->updateFile('event1.ics', $calendarData);
+		$this->assertEquals($localEtag, $result);
+	}
+
+	public function testDeleteFile(): void {
+		$this->federatedCalendarService->expects(self::once())
+			->method('deleteCalendarObject')
+			->with($this->federationInfo, 'event1.ics');
+
+		$this->caldavBackend->expects(self::once())
+			->method('deleteCalendarObject')
+			->with(10, 'event1.ics', 2);
+
+		$this->federatedCalendar->deleteFile('event1.ics');
+	}
+}