Merge pull request #3044 from nextcloud/dav-email-reminders

Calendar events email reminders

35 files changed, 5189 insertions, 7 deletions

diff --git a/3rdparty b/3rdparty
-Subproject ef289bc27eae0cdfc3f74f419ace8dda8dd84ef
+Subproject 49ccfbb28661b9ef7743c1725cd257125921592
diff --git a/apps/dav/appinfo/app.php b/apps/dav/appinfo/app.php
index 70d01088be2..dd9e0e9c096 100644
--- a/apps/dav/appinfo/app.php
+++ b/apps/dav/appinfo/app.php
@@ -108,3 +108,6 @@ $calendarManager->register(function() use ($calendarManager, $app) {
 		$app->setupCalendarProvider($calendarManager, $user->getUID());
 	}
 });
+
+$app->registerNotifier();
+$app->registerCalendarReminders();
diff --git a/apps/dav/appinfo/info.xml b/apps/dav/appinfo/info.xml
index dc90ac58188..6b593b97b70 100644
--- a/apps/dav/appinfo/info.xml
+++ b/apps/dav/appinfo/info.xml
@@ -5,7 +5,7 @@
 	<name>WebDAV</name>
 	<summary>WebDAV endpoint</summary>
 	<description>WebDAV endpoint</description>
-	<version>1.11.1</version>
+	<version>1.13.0</version>
 	<licence>agpl</licence>
 	<author>owncloud.org</author>
 	<namespace>DAV</namespace>
@@ -23,6 +23,7 @@
 		<job>OCA\DAV\BackgroundJob\CleanupDirectLinksJob</job>
 		<job>OCA\DAV\BackgroundJob\UpdateCalendarResourcesRoomsBackgroundJob</job>
 		<job>OCA\DAV\BackgroundJob\CleanupInvitationTokenJob</job>
+		<job>OCA\DAV\BackgroundJob\EventReminderJob</job>
 	</background-jobs>
 
 	<repair-steps>
@@ -32,6 +33,7 @@
 			<step>OCA\DAV\Migration\CalDAVRemoveEmptyValue</step>
 			<step>OCA\DAV\Migration\BuildCalendarSearchIndex</step>
 			<step>OCA\DAV\Migration\RefreshWebcalJobRegistrar</step>
+			<step>OCA\DAV\Migration\RegisterBuildReminderIndexBackgroundJob</step>
 			<step>OCA\DAV\Migration\RemoveOrphanEventsAndContacts</step>
 			<step>OCA\DAV\Migration\RemoveClassifiedEventActivity</step>
 		</post-migration>
@@ -45,6 +47,7 @@
 		<command>OCA\DAV\Command\CreateCalendar</command>
 		<command>OCA\DAV\Command\MoveCalendar</command>
 		<command>OCA\DAV\Command\ListCalendars</command>
+		<command>OCA\DAV\Command\SendEventReminders</command>
 		<command>OCA\DAV\Command\SyncBirthdayCalendar</command>
 		<command>OCA\DAV\Command\SyncSystemAddressBook</command>
 		<command>OCA\DAV\Command\RemoveInvalidShares</command>
diff --git a/apps/dav/composer/composer/autoload_classmap.php b/apps/dav/composer/composer/autoload_classmap.php
index 694231eebda..1084430719a 100644
--- a/apps/dav/composer/composer/autoload_classmap.php
+++ b/apps/dav/composer/composer/autoload_classmap.php
@@ -11,8 +11,10 @@ return array(
     'OCA\\DAV\\Avatars\\AvatarHome' => $baseDir . '/../lib/Avatars/AvatarHome.php',
     'OCA\\DAV\\Avatars\\AvatarNode' => $baseDir . '/../lib/Avatars/AvatarNode.php',
     'OCA\\DAV\\Avatars\\RootCollection' => $baseDir . '/../lib/Avatars/RootCollection.php',
+    'OCA\\DAV\\BackgroundJob\\BuildReminderIndexBackgroundJob' => $baseDir . '/../lib/BackgroundJob/BuildReminderIndexBackgroundJob.php',
     'OCA\\DAV\\BackgroundJob\\CleanupDirectLinksJob' => $baseDir . '/../lib/BackgroundJob/CleanupDirectLinksJob.php',
     'OCA\\DAV\\BackgroundJob\\CleanupInvitationTokenJob' => $baseDir . '/../lib/BackgroundJob/CleanupInvitationTokenJob.php',
+    'OCA\\DAV\\BackgroundJob\\EventReminderJob' => $baseDir . '/../lib/BackgroundJob/EventReminderJob.php',
     'OCA\\DAV\\BackgroundJob\\GenerateBirthdayCalendarBackgroundJob' => $baseDir . '/../lib/BackgroundJob/GenerateBirthdayCalendarBackgroundJob.php',
     'OCA\\DAV\\BackgroundJob\\RefreshWebcalJob' => $baseDir . '/../lib/BackgroundJob/RefreshWebcalJob.php',
     'OCA\\DAV\\BackgroundJob\\RegisterRegenerateBirthdayCalendars' => $baseDir . '/../lib/BackgroundJob/RegisterRegenerateBirthdayCalendars.php',
@@ -51,6 +53,17 @@ return array(
     'OCA\\DAV\\CalDAV\\PublicCalendarRoot' => $baseDir . '/../lib/CalDAV/PublicCalendarRoot.php',
     'OCA\\DAV\\CalDAV\\Publishing\\PublishPlugin' => $baseDir . '/../lib/CalDAV/Publishing/PublishPlugin.php',
     'OCA\\DAV\\CalDAV\\Publishing\\Xml\\Publisher' => $baseDir . '/../lib/CalDAV/Publishing/Xml/Publisher.php',
+    'OCA\\DAV\\CalDAV\\Reminder\\Backend' => $baseDir . '/../lib/CalDAV/Reminder/Backend.php',
+    'OCA\\DAV\\CalDAV\\Reminder\\INotificationProvider' => $baseDir . '/../lib/CalDAV/Reminder/INotificationProvider.php',
+    'OCA\\DAV\\CalDAV\\Reminder\\NotificationProviderManager' => $baseDir . '/../lib/CalDAV/Reminder/NotificationProviderManager.php',
+    'OCA\\DAV\\CalDAV\\Reminder\\NotificationProvider\\AbstractProvider' => $baseDir . '/../lib/CalDAV/Reminder/NotificationProvider/AbstractProvider.php',
+    'OCA\\DAV\\CalDAV\\Reminder\\NotificationProvider\\AudioProvider' => $baseDir . '/../lib/CalDAV/Reminder/NotificationProvider/AudioProvider.php',
+    'OCA\\DAV\\CalDAV\\Reminder\\NotificationProvider\\EmailProvider' => $baseDir . '/../lib/CalDAV/Reminder/NotificationProvider/EmailProvider.php',
+    'OCA\\DAV\\CalDAV\\Reminder\\NotificationProvider\\ProviderNotAvailableException' => $baseDir . '/../lib/CalDAV/Reminder/NotificationProvider/ProviderNotAvailableException.php',
+    'OCA\\DAV\\CalDAV\\Reminder\\NotificationProvider\\PushProvider' => $baseDir . '/../lib/CalDAV/Reminder/NotificationProvider/PushProvider.php',
+    'OCA\\DAV\\CalDAV\\Reminder\\NotificationTypeDoesNotExistException' => $baseDir . '/../lib/CalDAV/Reminder/NotificationTypeDoesNotExistException.php',
+    'OCA\\DAV\\CalDAV\\Reminder\\Notifier' => $baseDir . '/../lib/CalDAV/Reminder/Notifier.php',
+    'OCA\\DAV\\CalDAV\\Reminder\\ReminderService' => $baseDir . '/../lib/CalDAV/Reminder/ReminderService.php',
     'OCA\\DAV\\CalDAV\\ResourceBooking\\AbstractPrincipalBackend' => $baseDir . '/../lib/CalDAV/ResourceBooking/AbstractPrincipalBackend.php',
     'OCA\\DAV\\CalDAV\\ResourceBooking\\ResourcePrincipalBackend' => $baseDir . '/../lib/CalDAV/ResourceBooking/ResourcePrincipalBackend.php',
     'OCA\\DAV\\CalDAV\\ResourceBooking\\RoomPrincipalBackend' => $baseDir . '/../lib/CalDAV/ResourceBooking/RoomPrincipalBackend.php',
@@ -86,6 +99,7 @@ return array(
     'OCA\\DAV\\Command\\ListCalendars' => $baseDir . '/../lib/Command/ListCalendars.php',
     'OCA\\DAV\\Command\\MoveCalendar' => $baseDir . '/../lib/Command/MoveCalendar.php',
     'OCA\\DAV\\Command\\RemoveInvalidShares' => $baseDir . '/../lib/Command/RemoveInvalidShares.php',
+    'OCA\\DAV\\Command\\SendEventReminders' => $baseDir . '/../lib/Command/SendEventReminders.php',
     'OCA\\DAV\\Command\\SyncBirthdayCalendar' => $baseDir . '/../lib/Command/SyncBirthdayCalendar.php',
     'OCA\\DAV\\Command\\SyncSystemAddressBook' => $baseDir . '/../lib/Command/SyncSystemAddressBook.php',
     'OCA\\DAV\\Comments\\CommentNode' => $baseDir . '/../lib/Comments/CommentNode.php',
@@ -166,6 +180,7 @@ return array(
     'OCA\\DAV\\Migration\\FixBirthdayCalendarComponent' => $baseDir . '/../lib/Migration/FixBirthdayCalendarComponent.php',
     'OCA\\DAV\\Migration\\RefreshWebcalJobRegistrar' => $baseDir . '/../lib/Migration/RefreshWebcalJobRegistrar.php',
     'OCA\\DAV\\Migration\\RegenerateBirthdayCalendars' => $baseDir . '/../lib/Migration/RegenerateBirthdayCalendars.php',
+    'OCA\\DAV\\Migration\\RegisterBuildReminderIndexBackgroundJob' => $baseDir . '/../lib/Migration/RegisterBuildReminderIndexBackgroundJob.php',
     'OCA\\DAV\\Migration\\RemoveClassifiedEventActivity' => $baseDir . '/../lib/Migration/RemoveClassifiedEventActivity.php',
     'OCA\\DAV\\Migration\\RemoveOrphanEventsAndContacts' => $baseDir . '/../lib/Migration/RemoveOrphanEventsAndContacts.php',
     'OCA\\DAV\\Migration\\Version1004Date20170825134824' => $baseDir . '/../lib/Migration/Version1004Date20170825134824.php',
@@ -184,6 +199,7 @@ return array(
     'OCA\\DAV\\Migration\\Version1008Date20181114084440' => $baseDir . '/../lib/Migration/Version1008Date20181114084440.php',
     'OCA\\DAV\\Migration\\Version1011Date20190725113607' => $baseDir . '/../lib/Migration/Version1011Date20190725113607.php',
     'OCA\\DAV\\Migration\\Version1011Date20190806104428' => $baseDir . '/../lib/Migration/Version1011Date20190806104428.php',
+    'OCA\\DAV\\Migration\\Version1012Date20190808122342' => $baseDir . '/../lib/Migration/Version1012Date20190808122342.php',
     'OCA\\DAV\\Provisioning\\Apple\\AppleProvisioningNode' => $baseDir . '/../lib/Provisioning/Apple/AppleProvisioningNode.php',
     'OCA\\DAV\\Provisioning\\Apple\\AppleProvisioningPlugin' => $baseDir . '/../lib/Provisioning/Apple/AppleProvisioningPlugin.php',
     'OCA\\DAV\\RootCollection' => $baseDir . '/../lib/RootCollection.php',
diff --git a/apps/dav/composer/composer/autoload_static.php b/apps/dav/composer/composer/autoload_static.php
index 6f104916077..b3f5688166a 100644
--- a/apps/dav/composer/composer/autoload_static.php
+++ b/apps/dav/composer/composer/autoload_static.php
@@ -26,8 +26,10 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\Avatars\\AvatarHome' => __DIR__ . '/..' . '/../lib/Avatars/AvatarHome.php',
         'OCA\\DAV\\Avatars\\AvatarNode' => __DIR__ . '/..' . '/../lib/Avatars/AvatarNode.php',
         'OCA\\DAV\\Avatars\\RootCollection' => __DIR__ . '/..' . '/../lib/Avatars/RootCollection.php',
+        'OCA\\DAV\\BackgroundJob\\BuildReminderIndexBackgroundJob' => __DIR__ . '/..' . '/../lib/BackgroundJob/BuildReminderIndexBackgroundJob.php',
         'OCA\\DAV\\BackgroundJob\\CleanupDirectLinksJob' => __DIR__ . '/..' . '/../lib/BackgroundJob/CleanupDirectLinksJob.php',
         'OCA\\DAV\\BackgroundJob\\CleanupInvitationTokenJob' => __DIR__ . '/..' . '/../lib/BackgroundJob/CleanupInvitationTokenJob.php',
+        'OCA\\DAV\\BackgroundJob\\EventReminderJob' => __DIR__ . '/..' . '/../lib/BackgroundJob/EventReminderJob.php',
         'OCA\\DAV\\BackgroundJob\\GenerateBirthdayCalendarBackgroundJob' => __DIR__ . '/..' . '/../lib/BackgroundJob/GenerateBirthdayCalendarBackgroundJob.php',
         'OCA\\DAV\\BackgroundJob\\RefreshWebcalJob' => __DIR__ . '/..' . '/../lib/BackgroundJob/RefreshWebcalJob.php',
         'OCA\\DAV\\BackgroundJob\\RegisterRegenerateBirthdayCalendars' => __DIR__ . '/..' . '/../lib/BackgroundJob/RegisterRegenerateBirthdayCalendars.php',
@@ -66,6 +68,17 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\CalDAV\\PublicCalendarRoot' => __DIR__ . '/..' . '/../lib/CalDAV/PublicCalendarRoot.php',
         'OCA\\DAV\\CalDAV\\Publishing\\PublishPlugin' => __DIR__ . '/..' . '/../lib/CalDAV/Publishing/PublishPlugin.php',
         'OCA\\DAV\\CalDAV\\Publishing\\Xml\\Publisher' => __DIR__ . '/..' . '/../lib/CalDAV/Publishing/Xml/Publisher.php',
+        'OCA\\DAV\\CalDAV\\Reminder\\Backend' => __DIR__ . '/..' . '/../lib/CalDAV/Reminder/Backend.php',
+        'OCA\\DAV\\CalDAV\\Reminder\\INotificationProvider' => __DIR__ . '/..' . '/../lib/CalDAV/Reminder/INotificationProvider.php',
+        'OCA\\DAV\\CalDAV\\Reminder\\NotificationProviderManager' => __DIR__ . '/..' . '/../lib/CalDAV/Reminder/NotificationProviderManager.php',
+        'OCA\\DAV\\CalDAV\\Reminder\\NotificationProvider\\AbstractProvider' => __DIR__ . '/..' . '/../lib/CalDAV/Reminder/NotificationProvider/AbstractProvider.php',
+        'OCA\\DAV\\CalDAV\\Reminder\\NotificationProvider\\AudioProvider' => __DIR__ . '/..' . '/../lib/CalDAV/Reminder/NotificationProvider/AudioProvider.php',
+        'OCA\\DAV\\CalDAV\\Reminder\\NotificationProvider\\EmailProvider' => __DIR__ . '/..' . '/../lib/CalDAV/Reminder/NotificationProvider/EmailProvider.php',
+        'OCA\\DAV\\CalDAV\\Reminder\\NotificationProvider\\ProviderNotAvailableException' => __DIR__ . '/..' . '/../lib/CalDAV/Reminder/NotificationProvider/ProviderNotAvailableException.php',
+        'OCA\\DAV\\CalDAV\\Reminder\\NotificationProvider\\PushProvider' => __DIR__ . '/..' . '/../lib/CalDAV/Reminder/NotificationProvider/PushProvider.php',
+        'OCA\\DAV\\CalDAV\\Reminder\\NotificationTypeDoesNotExistException' => __DIR__ . '/..' . '/../lib/CalDAV/Reminder/NotificationTypeDoesNotExistException.php',
+        'OCA\\DAV\\CalDAV\\Reminder\\Notifier' => __DIR__ . '/..' . '/../lib/CalDAV/Reminder/Notifier.php',
+        'OCA\\DAV\\CalDAV\\Reminder\\ReminderService' => __DIR__ . '/..' . '/../lib/CalDAV/Reminder/ReminderService.php',
         'OCA\\DAV\\CalDAV\\ResourceBooking\\AbstractPrincipalBackend' => __DIR__ . '/..' . '/../lib/CalDAV/ResourceBooking/AbstractPrincipalBackend.php',
         'OCA\\DAV\\CalDAV\\ResourceBooking\\ResourcePrincipalBackend' => __DIR__ . '/..' . '/../lib/CalDAV/ResourceBooking/ResourcePrincipalBackend.php',
         'OCA\\DAV\\CalDAV\\ResourceBooking\\RoomPrincipalBackend' => __DIR__ . '/..' . '/../lib/CalDAV/ResourceBooking/RoomPrincipalBackend.php',
@@ -101,6 +114,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\Command\\ListCalendars' => __DIR__ . '/..' . '/../lib/Command/ListCalendars.php',
         'OCA\\DAV\\Command\\MoveCalendar' => __DIR__ . '/..' . '/../lib/Command/MoveCalendar.php',
         'OCA\\DAV\\Command\\RemoveInvalidShares' => __DIR__ . '/..' . '/../lib/Command/RemoveInvalidShares.php',
+        'OCA\\DAV\\Command\\SendEventReminders' => __DIR__ . '/..' . '/../lib/Command/SendEventReminders.php',
         'OCA\\DAV\\Command\\SyncBirthdayCalendar' => __DIR__ . '/..' . '/../lib/Command/SyncBirthdayCalendar.php',
         'OCA\\DAV\\Command\\SyncSystemAddressBook' => __DIR__ . '/..' . '/../lib/Command/SyncSystemAddressBook.php',
         'OCA\\DAV\\Comments\\CommentNode' => __DIR__ . '/..' . '/../lib/Comments/CommentNode.php',
@@ -181,6 +195,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\Migration\\FixBirthdayCalendarComponent' => __DIR__ . '/..' . '/../lib/Migration/FixBirthdayCalendarComponent.php',
         'OCA\\DAV\\Migration\\RefreshWebcalJobRegistrar' => __DIR__ . '/..' . '/../lib/Migration/RefreshWebcalJobRegistrar.php',
         'OCA\\DAV\\Migration\\RegenerateBirthdayCalendars' => __DIR__ . '/..' . '/../lib/Migration/RegenerateBirthdayCalendars.php',
+        'OCA\\DAV\\Migration\\RegisterBuildReminderIndexBackgroundJob' => __DIR__ . '/..' . '/../lib/Migration/RegisterBuildReminderIndexBackgroundJob.php',
         'OCA\\DAV\\Migration\\RemoveClassifiedEventActivity' => __DIR__ . '/..' . '/../lib/Migration/RemoveClassifiedEventActivity.php',
         'OCA\\DAV\\Migration\\RemoveOrphanEventsAndContacts' => __DIR__ . '/..' . '/../lib/Migration/RemoveOrphanEventsAndContacts.php',
         'OCA\\DAV\\Migration\\Version1004Date20170825134824' => __DIR__ . '/..' . '/../lib/Migration/Version1004Date20170825134824.php',
@@ -199,6 +214,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\Migration\\Version1008Date20181114084440' => __DIR__ . '/..' . '/../lib/Migration/Version1008Date20181114084440.php',
         'OCA\\DAV\\Migration\\Version1011Date20190725113607' => __DIR__ . '/..' . '/../lib/Migration/Version1011Date20190725113607.php',
         'OCA\\DAV\\Migration\\Version1011Date20190806104428' => __DIR__ . '/..' . '/../lib/Migration/Version1011Date20190806104428.php',
+        'OCA\\DAV\\Migration\\Version1012Date20190808122342' => __DIR__ . '/..' . '/../lib/Migration/Version1012Date20190808122342.php',
         'OCA\\DAV\\Provisioning\\Apple\\AppleProvisioningNode' => __DIR__ . '/..' . '/../lib/Provisioning/Apple/AppleProvisioningNode.php',
         'OCA\\DAV\\Provisioning\\Apple\\AppleProvisioningPlugin' => __DIR__ . '/..' . '/../lib/Provisioning/Apple/AppleProvisioningPlugin.php',
         'OCA\\DAV\\RootCollection' => __DIR__ . '/..' . '/../lib/RootCollection.php',
diff --git a/apps/dav/js/settings-admin-caldav.js b/apps/dav/js/settings-admin-caldav.js
index 1a40c208dfe..ad30ba6ad37 100644
--- a/apps/dav/js/settings-admin-caldav.js
+++ b/apps/dav/js/settings-admin-caldav.js
@@ -36,3 +36,9 @@ $('#caldavGenerateBirthdayCalendar').change(function() {
 		$.post(OC.generateUrl('/apps/dav/disableBirthdayCalendar'));
 	}
 });
+
+$('#caldavSendRemindersNotifications').change(function() {
+	var val = $(this)[0].checked;
+
+	OCP.AppConfig.setValue('dav', 'sendEventReminders', val ? 'yes' : 'no');
+});
diff --git a/apps/dav/lib/AppInfo/Application.php b/apps/dav/lib/AppInfo/Application.php
index 41570ee7442..80e9dea8829 100644
--- a/apps/dav/lib/AppInfo/Application.php
+++ b/apps/dav/lib/AppInfo/Application.php
@@ -30,6 +30,13 @@ use OCA\DAV\CalDAV\Activity\Backend;
 use OCA\DAV\CalDAV\Activity\Provider\Event;
 use OCA\DAV\CalDAV\BirthdayService;
 use OCA\DAV\CalDAV\CalendarManager;
+use OCA\DAV\CalDAV\Reminder\Backend as ReminderBackend;
+use OCA\DAV\CalDAV\Reminder\NotificationProvider\AudioProvider;
+use OCA\DAV\CalDAV\Reminder\NotificationProvider\EmailProvider;
+use OCA\DAV\CalDAV\Reminder\NotificationProvider\PushProvider;
+use OCA\DAV\CalDAV\Reminder\NotificationProviderManager;
+use OCA\DAV\CalDAV\Reminder\Notifier;
+use OCA\DAV\CalDAV\Reminder\ReminderService;
 use OCA\DAV\Capabilities;
 use OCA\DAV\CardDAV\ContactsManager;
 use OCA\DAV\CardDAV\PhotoCache;
@@ -43,6 +50,8 @@ use Symfony\Component\EventDispatcher\GenericEvent;
 
 class Application extends App {
 
+	const APP_ID = 'dav';
+
 	/**
 	 * Application constructor.
 	 */
@@ -109,8 +118,7 @@ class Application extends App {
 			}
 		});
 
-		// carddav/caldav sync event setup
-		$listener = function($event) {
+		$birthdayListener = function ($event) {
 			if ($event instanceof GenericEvent) {
 				/** @var BirthdayService $b */
 				$b = $this->getContainer()->query(BirthdayService::class);
@@ -122,9 +130,9 @@ class Application extends App {
 			}
 		};
 
-		$dispatcher->addListener('\OCA\DAV\CardDAV\CardDavBackend::createCard', $listener);
-		$dispatcher->addListener('\OCA\DAV\CardDAV\CardDavBackend::updateCard', $listener);
-		$dispatcher->addListener('\OCA\DAV\CardDAV\CardDavBackend::deleteCard', function($event) {
+		$dispatcher->addListener('\OCA\DAV\CardDAV\CardDavBackend::createCard', $birthdayListener);
+		$dispatcher->addListener('\OCA\DAV\CardDAV\CardDavBackend::updateCard', $birthdayListener);
+		$dispatcher->addListener('\OCA\DAV\CardDAV\CardDavBackend::deleteCard', function ($event) {
 			if ($event instanceof GenericEvent) {
 				/** @var BirthdayService $b */
 				$b = $this->getContainer()->query(BirthdayService::class);
@@ -177,6 +185,11 @@ class Application extends App {
 				$event->getArgument('calendarData'),
 				$event->getArgument('shares')
 			);
+
+			$reminderBackend = $this->getContainer()->query(ReminderBackend::class);
+			$reminderBackend->cleanRemindersForCalendar(
+				$event->getArgument('calendarId')
+			);
 		});
 		$dispatcher->addListener('\OCA\DAV\CalDAV\CalDavBackend::updateShares', function(GenericEvent $event) {
 			/** @var Backend $backend */
@@ -187,6 +200,8 @@ class Application extends App {
 				$event->getArgument('add'),
 				$event->getArgument('remove')
 			);
+
+			// Here we should recalculate if reminders should be sent to new or old sharees
 		});
 
 		$dispatcher->addListener('\OCA\DAV\CalDAV\CalDavBackend::publishCalendar', function(GenericEvent $event) {
@@ -214,6 +229,14 @@ class Application extends App {
 				$event->getArgument('shares'),
 				$event->getArgument('objectData')
 			);
+
+			/** @var ReminderService $reminderBackend */
+			$reminderService = $this->getContainer()->query(ReminderService::class);
+
+			$reminderService->onTouchCalendarObject(
+				$eventName,
+				$event->getArgument('objectData')
+			);
 		};
 		$dispatcher->addListener('\OCA\DAV\CalDAV\CalDavBackend::createCalendarObject', $listener);
 		$dispatcher->addListener('\OCA\DAV\CalDAV\CalDavBackend::updateCalendarObject', $listener);
@@ -224,4 +247,23 @@ class Application extends App {
 		return $this->getContainer()->query(SyncService::class);
 	}
 
+	public function registerNotifier():void {
+		$this->getContainer()
+			->getServer()
+			->getNotificationManager()
+			->registerNotifierService(Notifier::class);
+	}
+
+	public function registerCalendarReminders():void {
+		try {
+			/** @var NotificationProviderManager $notificationProviderManager */
+			$notificationProviderManager = $this->getContainer()->query(NotificationProviderManager::class);
+			$notificationProviderManager->registerProvider(AudioProvider::class);
+			$notificationProviderManager->registerProvider(EmailProvider::class);
+			$notificationProviderManager->registerProvider(PushProvider::class);
+		} catch(\Exception $ex) {
+			$this->getContainer()->getServer()->getLogger()->logException($ex);
+		}
+	}
+
 }
diff --git a/apps/dav/lib/BackgroundJob/BuildReminderIndexBackgroundJob.php b/apps/dav/lib/BackgroundJob/BuildReminderIndexBackgroundJob.php
new file mode 100644
index 00000000000..15c52cd8525
--- /dev/null
+++ b/apps/dav/lib/BackgroundJob/BuildReminderIndexBackgroundJob.php
@@ -0,0 +1,134 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright 2019 Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\BackgroundJob;
+
+use OCP\BackgroundJob\QueuedJob;
+use OCA\DAV\CalDAV\Reminder\ReminderService;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\BackgroundJob\IJobList;
+use OCP\IDBConnection;
+use OCP\ILogger;
+
+/**
+ * Class BuildReminderIndexBackgroundJob
+ *
+ * @package OCA\DAV\BackgroundJob
+ */
+class BuildReminderIndexBackgroundJob extends QueuedJob {
+
+	/** @var IDBConnection */
+	private $db;
+
+	/** @var ReminderService */
+	private $reminderService;
+
+	/** @var ILogger */
+	private $logger;
+
+	/** @var IJobList */
+	private $jobList;
+
+	/** @var ITimeFactory */
+	private $timeFactory;
+
+	/**
+	 * BuildReminderIndexBackgroundJob constructor.
+	 *
+	 * @param IDBConnection $db
+	 * @param ReminderService $reminderService
+	 * @param ILogger $logger
+	 * @param IJobList $jobList
+	 * @param ITimeFactory $timeFactory
+	 */
+	public function __construct(IDBConnection $db,
+								ReminderService $reminderService,
+								ILogger $logger,
+								IJobList $jobList,
+								ITimeFactory $timeFactory) {
+		$this->db = $db;
+		$this->reminderService = $reminderService;
+		$this->logger = $logger;
+		$this->jobList = $jobList;
+		$this->timeFactory = $timeFactory;
+	}
+
+	/**
+	 * @param $arguments
+	 */
+	public function run($arguments) {
+		$offset = (int) $arguments['offset'];
+		$stopAt = (int) $arguments['stopAt'];
+
+		$this->logger->info('Building calendar reminder index (' . $offset .'/' . $stopAt . ')');
+
+		$offset = $this->buildIndex($offset, $stopAt);
+
+		if ($offset >= $stopAt) {
+			$this->logger->info('Building calendar reminder index done');
+		} else {
+			$this->jobList->add(self::class, [
+				'offset' => $offset,
+				'stopAt' => $stopAt
+			]);
+			$this->logger->info('Scheduled a new BuildReminderIndexBackgroundJob with offset ' . $offset);
+		}
+	}
+
+	/**
+	 * @param int $offset
+	 * @param int $stopAt
+	 * @return int
+	 */
+	private function buildIndex(int $offset, int $stopAt):int {
+		$startTime = $this->timeFactory->getTime();
+
+		$query = $this->db->getQueryBuilder();
+		$query->select('*')
+			->from('calendarobjects')
+			->where($query->expr()->lte('id', $query->createNamedParameter($stopAt)))
+			->andWhere($query->expr()->gt('id', $query->createNamedParameter($offset)))
+			->orderBy('id', 'ASC');
+
+		$stmt = $query->execute();
+		while($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
+			$offset = $row['id'];
+			if (is_resource($row['calendardata'])) {
+				$row['calendardata'] = stream_get_contents($row['calendardata']);
+			}
+			$row['component'] = $row['componenttype'];
+
+			try {
+				$this->reminderService->onTouchCalendarObject('\OCA\DAV\CalDAV\CalDavBackend::createCalendarObject', $row);
+			} catch(\Exception $ex) {
+				$this->logger->logException($ex);
+			}
+
+			if (($this->timeFactory->getTime() - $startTime) > 15) {
+				return $offset;
+			}
+		}
+
+		return $stopAt;
+	}
+}
\ No newline at end of file
diff --git a/apps/dav/lib/BackgroundJob/EventReminderJob.php b/apps/dav/lib/BackgroundJob/EventReminderJob.php
new file mode 100644
index 00000000000..dfa76ffe168
--- /dev/null
+++ b/apps/dav/lib/BackgroundJob/EventReminderJob.php
@@ -0,0 +1,64 @@
+<?php
+/**
+ * @author Thomas Citharel <tcit@tcit.fr>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+namespace OCA\DAV\BackgroundJob;
+
+use OC\BackgroundJob\TimedJob;
+use OCA\DAV\CalDAV\Reminder\ReminderService;
+use OCP\IConfig;
+
+class EventReminderJob extends TimedJob {
+
+	/** @var ReminderService */
+	private $reminderService;
+
+	/** @var IConfig */
+	private $config;
+
+	/**
+	 * EventReminderJob constructor.
+	 *
+	 * @param ReminderService $reminderService
+	 * @param IConfig $config
+	 */
+	public function __construct(ReminderService $reminderService, IConfig $config) {
+		$this->reminderService = $reminderService;
+		$this->config = $config;
+		/** Run every 5 minutes */
+		$this->setInterval(5);
+	}
+
+	/**
+	 * @param $arg
+	 * @throws \OCA\DAV\CalDAV\Reminder\NotificationProvider\ProviderNotAvailableException
+	 * @throws \OCA\DAV\CalDAV\Reminder\NotificationTypeDoesNotExistException
+	 * @throws \OC\User\NoUserException
+	 */
+	public function run($arg):void {
+		if ($this->config->getAppValue('dav', 'sendEventReminders', 'yes') !== 'yes') {
+			return;
+		}
+
+		if ($this->config->getAppValue('dav', 'sendEventRemindersMode', 'backgroundjob') !== 'backgroundjob') {
+			return;
+		}
+
+		$this->reminderService->processReminders();
+	}
+}
diff --git a/apps/dav/lib/CalDAV/CalDavBackend.php b/apps/dav/lib/CalDAV/CalDavBackend.php
index 91281dc0cb3..62d3909ce39 100644
--- a/apps/dav/lib/CalDAV/CalDavBackend.php
+++ b/apps/dav/lib/CalDAV/CalDavBackend.php
@@ -1135,7 +1135,6 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	 */
 	function updateCalendarObject($calendarId, $objectUri, $calendarData, $calendarType=self::CALENDAR_TYPE_CALENDAR) {
 		$extraData = $this->getDenormalizedData($calendarData);
-
 		$query = $this->db->getQueryBuilder();
 		$query->update('calendarobjects')
 				->set('calendardata', $query->createNamedParameter($calendarData, IQueryBuilder::PARAM_LOB))
diff --git a/apps/dav/lib/CalDAV/Reminder/Backend.php b/apps/dav/lib/CalDAV/Reminder/Backend.php
new file mode 100644
index 00000000000..b3cc013fb3e
--- /dev/null
+++ b/apps/dav/lib/CalDAV/Reminder/Backend.php
@@ -0,0 +1,219 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\Reminder;
+
+use OCP\IDBConnection;
+use OCP\AppFramework\Utility\ITimeFactory;
+
+/**
+ * Class Backend
+ *
+ * @package OCA\DAV\CalDAV\Reminder
+ */
+class Backend {
+
+	/** @var IDBConnection */
+	protected $db;
+
+	/** @var ITimeFactory */
+	private $timeFactory;
+
+	/**
+	 * Backend constructor.
+	 *
+	 * @param IDBConnection $db
+	 * @param ITimeFactory $timeFactory
+	 */
+	public function __construct(IDBConnection $db,
+								ITimeFactory $timeFactory) {
+		$this->db = $db;
+		$this->timeFactory = $timeFactory;
+	}
+
+	/**
+	 * Get all reminders with a notification date before now
+	 *
+	 * @return array
+	 * @throws \Exception
+	 */
+	public function getRemindersToProcess():array {
+		$query = $this->db->getQueryBuilder();
+		$query->select(['cr.*', 'co.calendardata', 'c.displayname', 'c.principaluri'])
+			->from('calendar_reminders', 'cr')
+			->where($query->expr()->lte('cr.notification_date', $query->createNamedParameter($this->timeFactory->getTime())))
+			->leftJoin('cr', 'calendarobjects', 'co', $query->expr()->eq('cr.object_id', 'co.id'))
+			->leftJoin('cr', 'calendars', 'c', $query->expr()->eq('cr.calendar_id', 'c.id'));
+		$stmt = $query->execute();
+
+		return array_map(
+			[$this, 'fixRowTyping'],
+			$stmt->fetchAll()
+		);
+	}
+
+	/**
+	 * Get all scheduled reminders for an event
+	 *
+	 * @param int $objectId
+	 * @return array
+	 */
+	public function getAllScheduledRemindersForEvent(int $objectId):array {
+		$query = $this->db->getQueryBuilder();
+		$query->select('*')
+			->from('calendar_reminders')
+			->where($query->expr()->eq('object_id', $query->createNamedParameter($objectId)));
+		$stmt = $query->execute();
+
+		return array_map(
+			[$this, 'fixRowTyping'],
+			$stmt->fetchAll()
+		);
+	}
+
+	/**
+	 * Insert a new reminder into the database
+	 *
+	 * @param int $calendarId
+	 * @param int $objectId
+	 * @param string $uid
+	 * @param bool $isRecurring
+	 * @param int $recurrenceId
+	 * @param bool $isRecurrenceException
+	 * @param string $eventHash
+	 * @param string $alarmHash
+	 * @param string $type
+	 * @param bool $isRelative
+	 * @param int $notificationDate
+	 * @param bool $isRepeatBased
+	 * @return int The insert id
+	 */
+	public function insertReminder(int $calendarId,
+								   int $objectId,
+								   string $uid,
+								   bool $isRecurring,
+								   int $recurrenceId,
+								   bool $isRecurrenceException,
+								   string $eventHash,
+								   string $alarmHash,
+								   string $type,
+								   bool $isRelative,
+								   int $notificationDate,
+								   bool $isRepeatBased):int {
+		$query = $this->db->getQueryBuilder();
+		$query->insert('calendar_reminders')
+			->values([
+				'calendar_id' => $query->createNamedParameter($calendarId),
+				'object_id' => $query->createNamedParameter($objectId),
+				'uid' => $query->createNamedParameter($uid),
+				'is_recurring' => $query->createNamedParameter($isRecurring ? 1 : 0),
+				'recurrence_id' => $query->createNamedParameter($recurrenceId),
+				'is_recurrence_exception' => $query->createNamedParameter($isRecurrenceException ? 1 : 0),
+				'event_hash' => $query->createNamedParameter($eventHash),
+				'alarm_hash' => $query->createNamedParameter($alarmHash),
+				'type' => $query->createNamedParameter($type),
+				'is_relative' => $query->createNamedParameter($isRelative ? 1 : 0),
+				'notification_date' => $query->createNamedParameter($notificationDate),
+				'is_repeat_based' => $query->createNamedParameter($isRepeatBased ? 1 : 0),
+			])
+			->execute();
+
+		return $query->getLastInsertId();
+	}
+
+	/**
+	 * Sets a new notificationDate on an existing reminder
+	 *
+	 * @param int $reminderId
+	 * @param int $newNotificationDate
+	 */
+	public function updateReminder(int $reminderId,
+								   int $newNotificationDate):void {
+		$query = $this->db->getQueryBuilder();
+		$query->update('calendar_reminders')
+			->set('notification_date', $query->createNamedParameter($newNotificationDate))
+			->where($query->expr()->eq('id', $query->createNamedParameter($reminderId)))
+			->execute();
+	}
+
+	/**
+	 * Remove a reminder by it's id
+	 *
+	 * @param integer $reminderId
+	 * @return void
+	 */
+	public function removeReminder(int $reminderId):void {
+		$query = $this->db->getQueryBuilder();
+
+		$query->delete('calendar_reminders')
+			->where($query->expr()->eq('id', $query->createNamedParameter($reminderId)))
+			->execute();
+	}
+
+	/**
+	 * Cleans reminders in database
+	 *
+	 * @param int $objectId
+	 */
+	public function cleanRemindersForEvent(int $objectId):void {
+		$query = $this->db->getQueryBuilder();
+
+		$query->delete('calendar_reminders')
+			->where($query->expr()->eq('object_id', $query->createNamedParameter($objectId)))
+			->execute();
+	}
+
+	/**
+	 * Remove all reminders for a calendar
+	 *
+	 * @param int $calendarId
+	 * @return void
+	 */
+	public function cleanRemindersForCalendar(int $calendarId):void {
+		$query = $this->db->getQueryBuilder();
+
+		$query->delete('calendar_reminders')
+			->where($query->expr()->eq('calendar_id', $query->createNamedParameter($calendarId)))
+			->execute();
+	}
+
+	/**
+	 * @param array $row
+	 * @return array
+	 */
+	private function fixRowTyping(array $row): array {
+		$row['id'] = (int) $row['id'];
+		$row['calendar_id'] = (int) $row['calendar_id'];
+		$row['object_id'] = (int) $row['object_id'];
+		$row['is_recurring'] = (bool) $row['is_recurring'];
+		$row['recurrence_id'] = (int) $row['recurrence_id'];
+		$row['is_recurrence_exception'] = (bool) $row['is_recurrence_exception'];
+		$row['is_relative'] = (bool) $row['is_relative'];
+		$row['notification_date'] = (int) $row['notification_date'];
+		$row['is_repeat_based'] = (bool) $row['is_repeat_based'];
+
+		return $row;
+	}
+}
diff --git a/apps/dav/lib/CalDAV/Reminder/INotificationProvider.php b/apps/dav/lib/CalDAV/Reminder/INotificationProvider.php
new file mode 100644
index 00000000000..d0e526eb0ee
--- /dev/null
+++ b/apps/dav/lib/CalDAV/Reminder/INotificationProvider.php
@@ -0,0 +1,47 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\Reminder;
+
+use OCP\IUser;
+use Sabre\VObject\Component\VEvent;
+
+/**
+ * Interface INotificationProvider
+ *
+ * @package OCA\DAV\CalDAV\Reminder
+ */
+interface INotificationProvider {
+
+	/**
+	 * Send notification
+	 *
+	 * @param VEvent $vevent
+	 * @param string $calendarDisplayName
+	 * @param IUser[] $users
+	 * @return void
+	 */
+	public function send(VEvent $vevent,
+						 string $calendarDisplayName,
+						 array $users=[]): void;
+}
\ No newline at end of file
diff --git a/apps/dav/lib/CalDAV/Reminder/NotificationProvider/AbstractProvider.php b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/AbstractProvider.php
new file mode 100644
index 00000000000..6e3a8eaddef
--- /dev/null
+++ b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/AbstractProvider.php
@@ -0,0 +1,188 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\Reminder\NotificationProvider;
+
+use OCA\DAV\CalDAV\Reminder\INotificationProvider;
+use OCP\IConfig;
+use OCP\IL10N;
+use OCP\ILogger;
+use OCP\IURLGenerator;
+use OCP\L10N\IFactory as L10NFactory;
+use OCP\IUser;
+use Sabre\VObject\Component\VEvent;
+use Sabre\VObject\DateTimeParser;
+use Sabre\VObject\Property;
+
+/**
+ * Class AbstractProvider
+ *
+ * @package OCA\DAV\CalDAV\Reminder\NotificationProvider
+ */
+abstract class AbstractProvider implements INotificationProvider  {
+
+	/** @var string */
+	public const NOTIFICATION_TYPE = '';
+
+	/** @var ILogger */
+	protected $logger;
+
+	/** @var L10NFactory */
+	private $l10nFactory;
+
+	/** @var IL10N[] */
+	private $l10ns;
+
+	/** @var string */
+	private $fallbackLanguage;
+
+	/** @var IURLGenerator */
+	protected $urlGenerator;
+
+	/** @var IConfig */
+	protected $config;
+
+	/**
+	 * @param ILogger $logger
+	 * @param L10NFactory $l10nFactory
+	 * @param IConfig $config
+	 * @param IUrlGenerator $urlGenerator
+	 */
+	public function __construct(ILogger $logger,
+								L10NFactory $l10nFactory,
+								IURLGenerator $urlGenerator,
+								IConfig $config) {
+		$this->logger = $logger;
+		$this->l10nFactory = $l10nFactory;
+		$this->urlGenerator = $urlGenerator;
+		$this->config = $config;
+	}
+
+	/**
+	 * Send notification
+	 *
+	 * @param VEvent $vevent
+	 * @param string $calendarDisplayName
+	 * @param IUser[] $users
+	 * @return void
+	 */
+	abstract public function send(VEvent $vevent,
+						   string $calendarDisplayName,
+						   array $users=[]): void;
+
+	/**
+	 * @return string
+	 */
+	protected function getFallbackLanguage():string {
+		if ($this->fallbackLanguage) {
+			return $this->fallbackLanguage;
+		}
+
+		$fallbackLanguage = $this->l10nFactory->findLanguage();
+		$this->fallbackLanguage = $fallbackLanguage;
+
+		return $fallbackLanguage;
+	}
+
+	/**
+	 * @param string $lang
+	 * @return bool
+	 */
+	protected function hasL10NForLang(string $lang):bool {
+		return $this->l10nFactory->languageExists('dav', $lang);
+	}
+
+	/**
+	 * @param string $lang
+	 * @return IL10N
+	 */
+	protected function getL10NForLang(string $lang):IL10N {
+		if (isset($this->l10ns[$lang])) {
+			return $this->l10ns[$lang];
+		}
+
+		$l10n = $this->l10nFactory->get('dav', $lang);
+		$this->l10ns[$lang] = $l10n;
+
+		return $l10n;
+	}
+
+	/**
+	 * @param VEvent $vevent
+	 * @return string
+	 */
+	private function getStatusOfEvent(VEvent $vevent):string {
+		if ($vevent->STATUS) {
+			return (string) $vevent->STATUS;
+		}
+
+		// Doesn't say so in the standard,
+		// but we consider events without a status
+		// to be confirmed
+		return 'CONFIRMED';
+	}
+
+	/**
+	 * @param VEvent $vevent
+	 * @return bool
+	 */
+	protected function isEventTentative(VEvent $vevent):bool {
+		return $this->getStatusOfEvent($vevent) === 'TENTATIVE';
+	}
+
+	/**
+	 * @param VEvent $vevent
+	 * @return Property\ICalendar\DateTime
+	 */
+	protected function getDTEndFromEvent(VEvent $vevent):Property\ICalendar\DateTime {
+		if (isset($vevent->DTEND)) {
+			return $vevent->DTEND;
+		}
+
+		if (isset($vevent->DURATION)) {
+			$isFloating = $vevent->DTSTART->isFloating();
+			/** @var Property\ICalendar\DateTime $end */
+			$end = clone $vevent->DTSTART;
+			$endDateTime = $end->getDateTime();
+			$endDateTime = $endDateTime->add(DateTimeParser::parse($vevent->DURATION->getValue()));
+			$end->setDateTime($endDateTime, $isFloating);
+
+			return $end;
+		}
+
+		if (!$vevent->DTSTART->hasTime()) {
+			$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;
+	}
+}
diff --git a/apps/dav/lib/CalDAV/Reminder/NotificationProvider/AudioProvider.php b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/AudioProvider.php
new file mode 100644
index 00000000000..ad4ac342f66
--- /dev/null
+++ b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/AudioProvider.php
@@ -0,0 +1,37 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+namespace OCA\DAV\CalDAV\Reminder\NotificationProvider;
+
+/**
+ * Class AudioProvider
+ *
+ * This class only extends PushProvider at the moment. It does not provide true
+ * audio-alarms yet, but it's better than no alarm at all right now.
+ *
+ * @package OCA\DAV\CalDAV\Reminder\NotificationProvider
+ */
+class AudioProvider extends PushProvider {
+
+	/** @var string */
+	public const NOTIFICATION_TYPE = 'AUDIO';
+}
diff --git a/apps/dav/lib/CalDAV/Reminder/NotificationProvider/EmailProvider.php b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/EmailProvider.php
new file mode 100644
index 00000000000..f5932a87b3e
--- /dev/null
+++ b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/EmailProvider.php
@@ -0,0 +1,503 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\Reminder\NotificationProvider;
+
+use \DateTime;
+use OCP\IConfig;
+use OCP\IL10N;
+use OCP\ILogger;
+use OCP\IURLGenerator;
+use OCP\L10N\IFactory as L10NFactory;
+use OCP\Mail\IEMailTemplate;
+use OCP\Mail\IMailer;
+use OCP\IUser;
+use Sabre\VObject\Component\VEvent;
+use Sabre\VObject;
+use Sabre\VObject\Parameter;
+use Sabre\VObject\Property;
+
+/**
+ * Class EmailProvider
+ *
+ * @package OCA\DAV\CalDAV\Reminder\NotificationProvider
+ */
+class EmailProvider extends AbstractProvider {
+
+	/** @var string */
+	public const NOTIFICATION_TYPE = 'EMAIL';
+
+	/** @var IMailer */
+	private $mailer;
+
+	/**
+	 * @param IConfig $config
+	 * @param IMailer $mailer
+	 * @param ILogger $logger
+	 * @param L10NFactory $l10nFactory
+	 * @param IUrlGenerator $urlGenerator
+	 */
+	public function __construct(IConfig $config,
+								IMailer $mailer,
+								ILogger $logger,
+								L10NFactory $l10nFactory,
+								IURLGenerator $urlGenerator) {
+		parent::__construct($logger, $l10nFactory, $urlGenerator, $config);
+		$this->mailer = $mailer;
+	}
+
+	/**
+	 * Send out notification via email
+	 *
+	 * @param VEvent $vevent
+	 * @param string $calendarDisplayName
+	 * @param array $users
+	 * @throws \Exception
+	 */
+	public function send(VEvent $vevent,
+						 string $calendarDisplayName,
+						 array $users=[]):void {
+		$fallbackLanguage = $this->getFallbackLanguage();
+
+		$emailAddressesOfSharees = $this->getEMailAddressesOfAllUsersWithWriteAccessToCalendar($users);
+		$emailAddressesOfAttendees = $this->getAllEMailAddressesFromEvent($vevent);
+
+		// Quote from php.net:
+		// If the input arrays have the same string keys, then the later value for that key will overwrite the previous one.
+		// => if there are duplicate email addresses, it will always take the system value
+		$emailAddresses = array_merge(
+			$emailAddressesOfAttendees,
+			$emailAddressesOfSharees
+		);
+
+		$sortedByLanguage = $this->sortEMailAddressesByLanguage($emailAddresses, $fallbackLanguage);
+		$organizer = $this->getOrganizerEMailAndNameFromEvent($vevent);
+
+		foreach($sortedByLanguage as $lang => $emailAddresses) {
+			if (!$this->hasL10NForLang($lang)) {
+				$lang = $fallbackLanguage;
+			}
+			$l10n = $this->getL10NForLang($lang);
+			$fromEMail = \OCP\Util::getDefaultEmailAddress('reminders-noreply');
+
+			$template = $this->mailer->createEMailTemplate('dav.calendarReminder');
+			$template->addHeader();
+			$this->addSubjectAndHeading($template, $l10n, $vevent);
+			$this->addBulletList($template, $l10n, $calendarDisplayName, $vevent);
+			$template->addFooter();
+
+			foreach ($emailAddresses as $emailAddress) {
+				$message = $this->mailer->createMessage();
+				$message->setFrom([$fromEMail]);
+				if ($organizer) {
+					$message->setReplyTo($organizer);
+				}
+				$message->setTo([$emailAddress]);
+				$message->useTemplate($template);
+
+				try {
+					$failed = $this->mailer->send($message);
+					if ($failed) {
+						$this->logger->error('Unable to deliver message to {failed}', ['app' => 'dav', 'failed' => implode(', ', $failed)]);
+					}
+				} catch (\Exception $ex) {
+					$this->logger->logException($ex, ['app' => 'dav']);
+				}
+			}
+		}
+	}
+
+	/**
+	 * @param IEMailTemplate $template
+	 * @param IL10N $l10n
+	 * @param VEvent $vevent
+	 */
+	private function addSubjectAndHeading(IEMailTemplate $template, IL10N $l10n, VEvent $vevent):void {
+		$template->setSubject('Notification: ' . $this->getTitleFromVEvent($vevent, $l10n));
+		$template->addHeading($this->getTitleFromVEvent($vevent, $l10n));
+	}
+
+	/**
+	 * @param IEMailTemplate $template
+	 * @param IL10N $l10n
+	 * @param string $calendarDisplayName
+	 * @param array $eventData
+	 */
+	private function addBulletList(IEMailTemplate $template,
+								   IL10N $l10n,
+								   string $calendarDisplayName,
+								   VEvent $vevent):void {
+		$template->addBodyListItem($calendarDisplayName, $l10n->t('Calendar:'),
+			$this->getAbsoluteImagePath('actions/info.svg'));
+
+		$template->addBodyListItem($this->generateDateString($l10n, $vevent), $l10n->t('Date:'),
+			$this->getAbsoluteImagePath('places/calendar.svg'));
+
+		if (isset($vevent->LOCATION)) {
+			$template->addBodyListItem((string) $vevent->LOCATION, $l10n->t('Where:'),
+				$this->getAbsoluteImagePath('actions/address.svg'));
+		}
+		if (isset($vevent->DESCRIPTION)) {
+			$template->addBodyListItem((string) $vevent->DESCRIPTION, $l10n->t('Description:'),
+				$this->getAbsoluteImagePath('actions/more.svg'));
+		}
+	}
+
+	/**
+	 * @param string $path
+	 * @return string
+	 */
+	private function getAbsoluteImagePath(string $path):string {
+		return $this->urlGenerator->getAbsoluteURL(
+			$this->urlGenerator->imagePath('core', $path)
+		);
+	}
+
+	/**
+	 * @param VEvent $vevent
+	 * @return array|null
+	 */
+	private function getOrganizerEMailAndNameFromEvent(VEvent $vevent):?array {
+		if (!$vevent->ORGANIZER) {
+			return null;
+		}
+
+		$organizer = $vevent->ORGANIZER;
+		if (strcasecmp($organizer->getValue(), 'mailto:') !== 0) {
+			return null;
+		}
+
+		$organizerEMail = substr($organizer->getValue(), 7);
+
+		$name = $organizer->offsetGet('CN');
+		if ($name instanceof Parameter) {
+			return [$organizerEMail => $name];
+		}
+
+		return [$organizerEMail];
+	}
+
+	/**
+	 * @param array $emails
+	 * @param string $defaultLanguage
+	 * @return array
+	 */
+	private function sortEMailAddressesByLanguage(array $emails,
+												  string $defaultLanguage):array {
+		$sortedByLanguage = [];
+
+		foreach($emails as $emailAddress => $parameters) {
+			if (isset($parameters['LANG'])) {
+				$lang = $parameters['LANG'];
+			} else {
+				$lang = $defaultLanguage;
+			}
+
+			if (!isset($sortedByLanguage[$lang])) {
+				$sortedByLanguage[$lang] = [];
+			}
+
+			$sortedByLanguage[$lang][] = $emailAddress;
+		}
+
+		return $sortedByLanguage;
+	}
+
+	/**
+	 * @param VEvent $vevent
+	 * @return array
+	 */
+	private function getAllEMailAddressesFromEvent(VEvent $vevent):array {
+		$emailAddresses = [];
+
+		if (isset($vevent->ATTENDEE)) {
+			foreach ($vevent->ATTENDEE as $attendee) {
+				if (!($attendee instanceof VObject\Property)) {
+					continue;
+				}
+
+				$cuType = $this->getCUTypeOfAttendee($attendee);
+				if (\in_array($cuType, ['RESOURCE', 'ROOM', 'UNKNOWN'])) {
+					// Don't send emails to things
+					continue;
+				}
+
+				$partstat = $this->getPartstatOfAttendee($attendee);
+				if ($partstat === 'DECLINED') {
+					// Don't send out emails to people who declined
+					continue;
+				}
+				if ($partstat === 'DELEGATED') {
+					$delegates = $attendee->offsetGet('DELEGATED-TO');
+					if (!($delegates instanceof VObject\Parameter)) {
+						continue;
+					}
+
+					$emailAddressesOfDelegates = $delegates->getParts();
+					foreach($emailAddressesOfDelegates as $addressesOfDelegate) {
+						if (strcasecmp($addressesOfDelegate, 'mailto:') === 0) {
+							$emailAddresses[substr($addressesOfDelegate, 7)] = [];
+						}
+					}
+
+					continue;
+				}
+
+				$emailAddressOfAttendee = $this->getEMailAddressOfAttendee($attendee);
+				if ($emailAddressOfAttendee !== null) {
+					$properties = [];
+
+					$langProp = $attendee->offsetGet('LANG');
+					if ($langProp instanceof VObject\Parameter) {
+						$properties['LANG'] = $langProp->getValue();
+					}
+
+					$emailAddresses[$emailAddressOfAttendee] = $properties;
+				}
+			}
+		}
+
+		if (isset($vevent->ORGANIZER) && $this->hasAttendeeMailURI($vevent->ORGANIZER)) {
+			$emailAddresses[$this->getEMailAddressOfAttendee($vevent->ORGANIZER)] = [];
+		}
+
+		return $emailAddresses;
+	}
+
+
+
+	/**
+	 * @param VObject\Property $attendee
+	 * @return string
+	 */
+	private function getCUTypeOfAttendee(VObject\Property $attendee):string {
+		$cuType = $attendee->offsetGet('CUTYPE');
+		if ($cuType instanceof VObject\Parameter) {
+			return strtoupper($cuType->getValue());
+		}
+
+		return 'INDIVIDUAL';
+	}
+
+	/**
+	 * @param VObject\Property $attendee
+	 * @return string
+	 */
+	private function getPartstatOfAttendee(VObject\Property $attendee):string {
+		$partstat = $attendee->offsetGet('PARTSTAT');
+		if ($partstat instanceof VObject\Parameter) {
+			return strtoupper($partstat->getValue());
+		}
+
+		return 'NEEDS-ACTION';
+	}
+
+	/**
+	 * @param VObject\Property $attendee
+	 * @return bool
+	 */
+	private function hasAttendeeMailURI(VObject\Property $attendee):bool {
+		return stripos($attendee->getValue(), 'mailto:') === 0;
+	}
+
+	/**
+	 * @param VObject\Property $attendee
+	 * @return string|null
+	 */
+	private function getEMailAddressOfAttendee(VObject\Property $attendee):?string {
+		if (!$this->hasAttendeeMailURI($attendee)) {
+			return null;
+		}
+
+		return substr($attendee->getValue(), 7);
+	}
+
+	/**
+	 * @param array $users
+	 * @return array
+	 */
+	private function getEMailAddressesOfAllUsersWithWriteAccessToCalendar(array $users):array {
+		$emailAddresses = [];
+
+		foreach($users as $user) {
+			$emailAddress = $user->getEMailAddress();
+			if ($emailAddress) {
+				$lang = $this->getLangForUser($user);
+				if ($lang) {
+					$emailAddresses[$emailAddress] = [
+						'LANG' => $lang,
+					];
+				} else {
+					$emailAddresses[$emailAddress] = [];
+				}
+			}
+		}
+
+		return $emailAddresses;
+	}
+
+	/**
+	 * @param IUser $user
+	 * @return string
+	 */
+	private function getLangForUser(IUser $user): ?string {
+		return $this->config->getUserValue($user->getUID(), 'core', 'lang', null);
+	}
+
+	/**
+	 * @param IL10N $l10n
+	 * @param VEvent $vevent
+	 * @return string
+	 * @throws \Exception
+	 */
+	private function generateDateString(IL10N $l10n, VEvent $vevent):string {
+		$isAllDay = $vevent->DTSTART instanceof Property\ICalendar\Date;
+
+		/** @var Property\ICalendar\Date | Property\ICalendar\DateTime $dtstart */
+		/** @var Property\ICalendar\Date | Property\ICalendar\DateTime $dtend */
+		/** @var \DateTimeImmutable $dtstartDt */
+		$dtstartDt = $vevent->DTSTART->getDateTime();
+		/** @var \DateTimeImmutable $dtendDt */
+		$dtendDt = $this->getDTEndFromEvent($vevent)->getDateTime();
+
+		$diff = $dtstartDt->diff($dtendDt);
+
+		/** @phan-suppress-next-line PhanUndeclaredClassMethod */
+		$dtstartDt = new \DateTime($dtstartDt->format(\DateTime::ATOM));
+		/** @phan-suppress-next-line PhanUndeclaredClassMethod */
+		$dtendDt = new \DateTime($dtendDt->format(\DateTime::ATOM));
+
+		if ($isAllDay) {
+			// One day event
+			if ($diff->days === 1) {
+				return $this->getDateString($l10n, $dtstartDt);
+			}
+
+			return implode(' - ', [
+				$this->getDateString($l10n, $dtstartDt),
+				$this->getDateString($l10n, $dtendDt),
+			]);
+		}
+
+		$startTimezone = $endTimezone = null;
+		if (!$vevent->DTSTART->isFloating()) {
+			/** @phan-suppress-next-line PhanUndeclaredClassMethod */
+			$startTimezone = $vevent->DTSTART->getDateTime()->getTimezone()->getName();
+			/** @phan-suppress-next-line PhanUndeclaredClassMethod */
+			$endTimezone = $this->getDTEndFromEvent($vevent)->getDateTime()->getTimezone()->getName();
+		}
+
+		$localeStart = implode(', ', [
+			$this->getWeekDayName($l10n, $dtstartDt),
+			$this->getDateTimeString($l10n, $dtstartDt)
+		]);
+
+		// always show full date with timezone if timezones are different
+		if ($startTimezone !== $endTimezone) {
+			$localeEnd = implode(', ', [
+				$this->getWeekDayName($l10n, $dtendDt),
+				$this->getDateTimeString($l10n, $dtendDt)
+			]);
+
+			return $localeStart
+				. ' (' . $startTimezone . ') '
+				. ' - '
+				. $localeEnd
+				. ' (' . $endTimezone . ')';
+		}
+
+		// Show only the time if the day is the same
+		$localeEnd = $this->isDayEqual($dtstartDt, $dtendDt)
+			? $this->getTimeString($l10n, $dtendDt)
+			: implode(', ', [
+				$this->getWeekDayName($l10n, $dtendDt),
+				$this->getDateTimeString($l10n, $dtendDt)
+			]);
+
+		return $localeStart
+			. ' - '
+			. $localeEnd
+			. ' (' . $startTimezone . ')';
+	}
+
+	/**
+	 * @param DateTime $dtStart
+	 * @param DateTime $dtEnd
+	 * @return bool
+	 */
+	private function isDayEqual(DateTime $dtStart,
+								DateTime $dtEnd):bool {
+		return $dtStart->format('Y-m-d') === $dtEnd->format('Y-m-d');
+	}
+
+	/**
+	 * @param IL10N $l10n
+	 * @param DateTime $dt
+	 * @return string
+	 */
+	private function getWeekDayName(IL10N $l10n, DateTime $dt):string {
+		return $l10n->l('weekdayName', $dt, ['width' => 'abbreviated']);
+	}
+
+	/**
+	 * @param IL10N $l10n
+	 * @param DateTime $dt
+	 * @return string
+	 */
+	private function getDateString(IL10N $l10n, DateTime $dt):string {
+		return $l10n->l('date', $dt, ['width' => 'medium']);
+	}
+
+	/**
+	 * @param IL10N $l10n
+	 * @param DateTime $dt
+	 * @return string
+	 */
+	private function getDateTimeString(IL10N $l10n, DateTime $dt):string {
+		return $l10n->l('datetime', $dt, ['width' => 'medium|short']);
+	}
+
+	/**
+	 * @param IL10N $l10n
+	 * @param DateTime $dt
+	 * @return string
+	 */
+	private function getTimeString(IL10N $l10n, DateTime $dt):string {
+		return $l10n->l('time', $dt, ['width' => 'short']);
+	}
+
+	/**
+	 * @param VEvent $vevent
+	 * @param IL10N $l10n
+	 * @return string
+	 */
+	private function getTitleFromVEvent(VEvent $vevent, IL10N $l10n):string {
+		if (isset($vevent->SUMMARY)) {
+			return (string)$vevent->SUMMARY;
+		}
+
+		return $l10n->t('Untitled event');
+	}
+}
diff --git a/apps/dav/lib/CalDAV/Reminder/NotificationProvider/ProviderNotAvailableException.php b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/ProviderNotAvailableException.php
new file mode 100644
index 00000000000..bfa6db95852
--- /dev/null
+++ b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/ProviderNotAvailableException.php
@@ -0,0 +1,39 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2018 Thomas Citharel <tcit@tcit.fr>
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ *
+ * @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\Reminder\NotificationProvider;
+
+class ProviderNotAvailableException extends \Exception {
+
+	/**
+	 * ProviderNotAvailableException constructor.
+	 *
+	 * @since 16.0.0
+	 *
+	 * @param string $type ReminderType
+	 */
+	public function __construct(string $type) {
+		parent::__construct("No notification provider for type $type available");
+	}
+
+}
diff --git a/apps/dav/lib/CalDAV/Reminder/NotificationProvider/PushProvider.php b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/PushProvider.php
new file mode 100644
index 00000000000..3872b67e596
--- /dev/null
+++ b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/PushProvider.php
@@ -0,0 +1,139 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\Reminder\NotificationProvider;
+
+use OCA\DAV\AppInfo\Application;
+use OCP\IConfig;
+use OCP\ILogger;
+use OCP\IURLGenerator;
+use OCP\L10N\IFactory as L10NFactory;
+use OCP\Notification\IManager;
+use OCP\IUser;
+use OCP\Notification\INotification;
+use OCP\AppFramework\Utility\ITimeFactory;
+use Sabre\VObject\Component\VEvent;
+use Sabre\VObject\Property;
+
+/**
+ * Class PushProvider
+ *
+ * @package OCA\DAV\CalDAV\Reminder\NotificationProvider
+ */
+class PushProvider extends AbstractProvider {
+
+	/** @var string */
+	public const NOTIFICATION_TYPE = 'DISPLAY';
+
+	/** @var IManager */
+	private $manager;
+
+	/** @var ITimeFactory */
+	private $timeFactory;
+
+	/**
+	 * @param IConfig $config
+	 * @param IManager $manager
+	 * @param ILogger $logger
+	 * @param L10NFactory $l10nFactory
+	 * @param IUrlGenerator $urlGenerator
+	 * @param ITimeFactory $timeFactory
+	 */
+	public function __construct(IConfig $config,
+								IManager $manager,
+								ILogger $logger,
+								L10NFactory $l10nFactory,
+								IURLGenerator $urlGenerator,
+								ITimeFactory $timeFactory) {
+		parent::__construct($logger, $l10nFactory, $urlGenerator, $config);
+		$this->manager = $manager;
+		$this->timeFactory = $timeFactory;
+	}
+
+	/**
+	 * Send push notification to all users.
+	 *
+	 * @param VEvent $vevent
+	 * @param string $calendarDisplayName
+	 * @param IUser[] $users
+	 * @throws \Exception
+	 */
+	public function send(VEvent $vevent,
+						 string $calendarDisplayName=null,
+						 array $users=[]):void {
+		$eventDetails = $this->extractEventDetails($vevent);
+		$eventDetails['calendar_displayname'] = $calendarDisplayName;
+
+		foreach($users as $user) {
+			/** @var INotification $notification */
+			$notification = $this->manager->createNotification();
+			$notification->setApp(Application::APP_ID)
+				->setUser($user->getUID())
+				->setDateTime($this->timeFactory->getDateTime())
+				->setObject(Application::APP_ID, (string) $vevent->UID)
+				->setSubject('calendar_reminder', [
+					'title' => $eventDetails['title'],
+					'start_atom' => $eventDetails['start_atom']
+				])
+				->setMessage('calendar_reminder', $eventDetails);
+
+			$this->manager->notify($notification);
+		}
+	}
+
+	/**
+	 * @var VEvent $vevent
+	 * @return array
+	 * @throws \Exception
+	 */
+	protected function extractEventDetails(VEvent $vevent):array {
+		/** @var Property\ICalendar\DateTime $start */
+		$start = $vevent->DTSTART;
+		$end = $this->getDTEndFromEvent($vevent);
+
+		return [
+			'title' => isset($vevent->SUMMARY)
+				? ((string) $vevent->SUMMARY)
+				: null,
+			'description' => isset($vevent->DESCRIPTION)
+				? ((string) $vevent->DESCRIPTION)
+				: null,
+			'location' => isset($vevent->LOCATION)
+				? ((string) $vevent->LOCATION)
+				: null,
+			'all_day' => $start instanceof Property\ICalendar\Date,
+			/** @phan-suppress-next-line PhanUndeclaredClassMethod */
+			'start_atom' => $start->getDateTime()->format(\DateTime::ATOM),
+			'start_is_floating' => $start->isFloating(),
+			/** @phan-suppress-next-line PhanUndeclaredClassMethod */
+			'start_timezone' => $start->getDateTime()->getTimezone()->getName(),
+			/** @phan-suppress-next-line PhanUndeclaredClassMethod */
+			'end_atom' => $end->getDateTime()->format(\DateTime::ATOM),
+			'end_is_floating' => $end->isFloating(),
+			/** @phan-suppress-next-line PhanUndeclaredClassMethod */
+			'end_timezone' => $end->getDateTime()->getTimezone()->getName(),
+		];
+	}
+}
diff --git a/apps/dav/lib/CalDAV/Reminder/NotificationProviderManager.php b/apps/dav/lib/CalDAV/Reminder/NotificationProviderManager.php
new file mode 100644
index 00000000000..c9bcf2dd064
--- /dev/null
+++ b/apps/dav/lib/CalDAV/Reminder/NotificationProviderManager.php
@@ -0,0 +1,81 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+namespace OCA\DAV\CalDAV\Reminder;
+
+/**
+ * Class NotificationProviderManager
+ *
+ * @package OCA\DAV\CalDAV\Reminder
+ */
+class NotificationProviderManager {
+
+	/** @var INotificationProvider[] */
+	private $providers = [];
+
+	/**
+	 * Checks whether a provider for a given ACTION exists
+	 *
+	 * @param string $type
+	 * @return bool
+	 */
+	public function hasProvider(string $type):bool {
+		return (\in_array($type, ReminderService::REMINDER_TYPES, true)
+			&& isset($this->providers[$type]));
+	}
+
+	/**
+	 * Get provider for a given ACTION
+	 *
+	 * @param string $type
+	 * @return INotificationProvider
+	 * @throws NotificationProvider\ProviderNotAvailableException
+	 * @throws NotificationTypeDoesNotExistException
+	 */
+	public function getProvider(string $type):INotificationProvider {
+		if (in_array($type, ReminderService::REMINDER_TYPES, true)) {
+			if (isset($this->providers[$type])) {
+				return $this->providers[$type];
+			}
+			throw new NotificationProvider\ProviderNotAvailableException($type);
+		}
+		throw new NotificationTypeDoesNotExistException($type);
+	}
+
+	/**
+	 * Registers a new provider
+	 *
+	 * @param string $providerClassName
+	 * @throws \OCP\AppFramework\QueryException
+	 */
+	public function registerProvider(string $providerClassName):void {
+		$provider = \OC::$server->query($providerClassName);
+
+		if (!$provider instanceof INotificationProvider) {
+			throw new \InvalidArgumentException('Invalid notification provider registered');
+		}
+
+		$this->providers[$provider::NOTIFICATION_TYPE] = $provider;
+	}
+}
diff --git a/apps/dav/lib/CalDAV/Reminder/NotificationTypeDoesNotExistException.php b/apps/dav/lib/CalDAV/Reminder/NotificationTypeDoesNotExistException.php
new file mode 100644
index 00000000000..c060089785a
--- /dev/null
+++ b/apps/dav/lib/CalDAV/Reminder/NotificationTypeDoesNotExistException.php
@@ -0,0 +1,40 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ *
+ * @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\Reminder;
+
+class NotificationTypeDoesNotExistException extends \Exception {
+
+	/**
+	 * NotificationTypeDoesNotExistException constructor.
+	 *
+	 * @since 16.0.0
+	 *
+	 * @param string $type ReminderType
+	 */
+	public function __construct(string $type) {
+		parent::__construct("Type $type is not an accepted type of notification");
+	}
+
+}
diff --git a/apps/dav/lib/CalDAV/Reminder/Notifier.php b/apps/dav/lib/CalDAV/Reminder/Notifier.php
new file mode 100644
index 00000000000..2c5f05f62ab
--- /dev/null
+++ b/apps/dav/lib/CalDAV/Reminder/Notifier.php
@@ -0,0 +1,316 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCA\DAV\CalDAV\Reminder;
+
+use \DateTime;
+use OCA\DAV\AppInfo\Application;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\IL10N;
+use OCP\L10N\IFactory;
+use OCP\Notification\INotification;
+use OCP\Notification\INotifier;
+use OCP\IURLGenerator;
+
+/**
+ * Class Notifier
+ *
+ * @package OCA\DAV\CalDAV\Reminder
+ */
+class Notifier implements INotifier {
+
+	/** @var IFactory */
+	private $l10nFactory;
+
+	/** @var IURLGenerator */
+	private $urlGenerator;
+
+	/** @var IL10N */
+	private $l10n;
+
+	/** @var ITimeFactory */
+	private $timeFactory;
+
+	/**
+	 * Notifier constructor.
+	 *
+	 * @param IFactory $factory
+	 * @param IURLGenerator $urlGenerator
+	 * @param ITimeFactory $timeFactory
+	 */
+	public function __construct(IFactory $factory,
+								IURLGenerator $urlGenerator,
+								ITimeFactory $timeFactory) {
+		$this->l10nFactory = $factory;
+		$this->urlGenerator = $urlGenerator;
+		$this->timeFactory = $timeFactory;
+	}
+
+	/**
+	 * Identifier of the notifier, only use [a-z0-9_]
+	 *
+	 * @return string
+	 * @since 17.0.0
+	 */
+	public function getID():string {
+		return Application::APP_ID;
+	}
+
+	/**
+	 * Human readable name describing the notifier
+	 *
+	 * @return string
+	 * @since 17.0.0
+	 */
+	public function getName():string {
+		return $this->l10nFactory->get('dav')->t('Calendar');
+	}
+
+	/**
+	 * Prepare sending the notification
+	 *
+	 * @param INotification $notification
+	 * @param string $languageCode The code of the language that should be used to prepare the notification
+	 * @return INotification
+	 * @throws \Exception
+	 */
+	public function prepare(INotification $notification,
+							string $languageCode):INotification {
+		if ($notification->getApp() !== Application::APP_ID) {
+			throw new \InvalidArgumentException('Notification not from this app');
+		}
+
+		// Read the language from the notification
+		$this->l10n = $this->l10nFactory->get('dav', $languageCode);
+
+		// Handle notifier subjects
+		switch($notification->getSubject()) {
+			case 'calendar_reminder':
+				return $this->prepareReminderNotification($notification);
+
+			default:
+				throw new \InvalidArgumentException('Unknown subject');
+
+		}
+	}
+
+	/**
+	 * @param INotification $notification
+	 * @return INotification
+	 */
+	private function prepareReminderNotification(INotification $notification):INotification {
+		$imagePath = $this->urlGenerator->imagePath('core', 'places/calendar.svg');
+		$iconUrl = $this->urlGenerator->getAbsoluteURL($imagePath);
+		$notification->setIcon($iconUrl);
+
+		$this->prepareNotificationSubject($notification);
+		$this->prepareNotificationMessage($notification);
+
+		return $notification;
+	}
+
+	/**
+	 * Sets the notification subject based on the parameters set in PushProvider
+	 *
+	 * @param INotification $notification
+	 */
+	private function prepareNotificationSubject(INotification $notification): void {
+		$parameters = $notification->getSubjectParameters();
+
+		$startTime = \DateTime::createFromFormat(\DateTime::ATOM, $parameters['start_atom']);
+		$now = $this->timeFactory->getDateTime();
+		$title = $this->getTitleFromParameters($parameters);
+
+		$diff = $startTime->diff($now);
+		if ($diff === false) {
+			return;
+		}
+
+		$components = [];
+		if ($diff->y) {
+			$components[] = $this->l10n->n('%n year', '%n years', $diff->y);
+		}
+		if ($diff->m) {
+			$components[] = $this->l10n->n('%n month', '%n months', $diff->m);
+		}
+		if ($diff->d) {
+			$components[] = $this->l10n->n('%n day', '%n days', $diff->d);
+		}
+		if ($diff->h) {
+			$components[] = $this->l10n->n('%n hour', '%n hours', $diff->h);
+		}
+		if ($diff->i) {
+			$components[] = $this->l10n->n('%n minute', '%n minutes', $diff->i);
+		}
+
+		// Limiting to the first three components to prevent
+		// the string from getting too long
+		$firstThreeComponents = array_slice($components, 0, 2);
+		$diffLabel = implode(', ', $firstThreeComponents);
+
+		if ($diff->invert) {
+			$title = $this->l10n->t('%s (in %s)', [$title, $diffLabel]);
+		} else {
+			$title = $this->l10n->t('%s (%s ago)', [$title, $diffLabel]);
+		}
+
+		$notification->setParsedSubject($title);
+	}
+
+	/**
+	 * Sets the notification message based on the parameters set in PushProvider
+	 *
+	 * @param INotification $notification
+	 */
+	private function prepareNotificationMessage(INotification $notification): void {
+		$parameters = $notification->getMessageParameters();
+
+		$description = [
+			$this->l10n->t('Calendar: %s', $parameters['calendar_displayname']),
+			$this->l10n->t('Date: %s', $this->generateDateString($parameters)),
+		];
+		if ($parameters['description']) {
+			$description[] = $this->l10n->t('Description: %s', $parameters['description']);
+		}
+		if ($parameters['location']) {
+			$description[] = $this->l10n->t('Where: %s', $parameters['location']);
+		}
+
+		$message = implode("\r\n", $description);
+		$notification->setParsedMessage($message);
+	}
+
+	/**
+	 * @param array $parameters
+	 * @return string
+	 */
+	private function getTitleFromParameters(array $parameters):string {
+		return $parameters['title'] ?? $this->l10n->t('Untitled event');
+	}
+
+	/**
+	 * @param array $parameters
+	 * @return string
+	 * @throws \Exception
+	 */
+	private function generateDateString(array $parameters):string {
+		$startDateTime = DateTime::createFromFormat(\DateTime::ATOM, $parameters['start_atom']);
+		$endDateTime = DateTime::createFromFormat(\DateTime::ATOM, $parameters['end_atom']);
+		$isAllDay = $parameters['all_day'];
+		$diff = $startDateTime->diff($endDateTime);
+
+		if ($isAllDay) {
+			// One day event
+			if ($diff->days === 1) {
+				return $this->getDateString($startDateTime);
+			}
+
+			return implode(' - ', [
+				$this->getDateString($startDateTime),
+				$this->getDateString($endDateTime),
+			]);
+		}
+
+		$startTimezone = $endTimezone = null;
+		if (!$parameters['start_is_floating']) {
+			$startTimezone = $parameters['start_timezone'];
+			$endTimezone = $parameters['end_timezone'];
+		}
+
+		$localeStart = implode(', ', [
+			$this->getWeekDayName($startDateTime),
+			$this->getDateTimeString($startDateTime)
+		]);
+
+		// always show full date with timezone if timezones are different
+		if ($startTimezone !== $endTimezone) {
+			$localeEnd = implode(', ', [
+				$this->getWeekDayName($endDateTime),
+				$this->getDateTimeString($endDateTime)
+			]);
+
+			return $localeStart
+				. ' (' . $startTimezone . ') '
+				. ' - '
+				. $localeEnd
+				. ' (' . $endTimezone . ')';
+		}
+
+		// Show only the time if the day is the same
+		$localeEnd = $this->isDayEqual($startDateTime, $endDateTime)
+			? $this->getTimeString($endDateTime)
+			: implode(', ', [
+				$this->getWeekDayName($endDateTime),
+				$this->getDateTimeString($endDateTime)
+			]);
+
+		return $localeStart
+			. ' - '
+			. $localeEnd
+			. ' (' . $startTimezone . ')';
+	}
+
+	/**
+	 * @param DateTime $dtStart
+	 * @param DateTime $dtEnd
+	 * @return bool
+	 */
+	private function isDayEqual(DateTime $dtStart,
+								DateTime $dtEnd):bool {
+		return $dtStart->format('Y-m-d') === $dtEnd->format('Y-m-d');
+	}
+
+	/**
+	 * @param DateTime $dt
+	 * @return string
+	 */
+	private function getWeekDayName(DateTime $dt):string {
+		return $this->l10n->l('weekdayName', $dt, ['width' => 'abbreviated']);
+	}
+
+	/**
+	 * @param DateTime $dt
+	 * @return string
+	 */
+	private function getDateString(DateTime $dt):string {
+		return $this->l10n->l('date', $dt, ['width' => 'medium']);
+	}
+
+	/**
+	 * @param DateTime $dt
+	 * @return string
+	 */
+	private function getDateTimeString(DateTime $dt):string {
+		return $this->l10n->l('datetime', $dt, ['width' => 'medium|short']);
+	}
+
+	/**
+	 * @param DateTime $dt
+	 * @return string
+	 */
+	private function getTimeString(DateTime $dt):string {
+		return $this->l10n->l('time', $dt, ['width' => 'short']);
+	}
+}
diff --git a/apps/dav/lib/CalDAV/Reminder/ReminderService.php b/apps/dav/lib/CalDAV/Reminder/ReminderService.php
new file mode 100644
index 00000000000..f36ddd157cc
--- /dev/null
+++ b/apps/dav/lib/CalDAV/Reminder/ReminderService.php
@@ -0,0 +1,761 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+namespace OCA\DAV\CalDAV\Reminder;
+
+use \DateTimeImmutable;
+use OCA\DAV\CalDAV\CalDavBackend;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\IGroup;
+use OCP\IGroupManager;
+use OCP\IUser;
+use OCP\IUserManager;
+use Sabre\VObject;
+use Sabre\VObject\Component\VAlarm;
+use Sabre\VObject\Component\VEvent;
+use Sabre\VObject\ParseException;
+use Sabre\VObject\Recur\EventIterator;
+use Sabre\VObject\Recur\NoInstancesException;
+
+class ReminderService {
+
+	/** @var Backend */
+	private $backend;
+
+	/** @var NotificationProviderManager */
+	private $notificationProviderManager;
+
+	/** @var IUserManager */
+	private $userManager;
+
+	/** @var IGroupManager */
+	private $groupManager;
+
+	/** @var CalDavBackend */
+	private $caldavBackend;
+
+	/** @var ITimeFactory */
+	private $timeFactory;
+
+	public const REMINDER_TYPE_EMAIL = 'EMAIL';
+	public const REMINDER_TYPE_DISPLAY = 'DISPLAY';
+	public const REMINDER_TYPE_AUDIO = 'AUDIO';
+
+	/**
+	 * @var String[]
+	 *
+	 * Official RFC5545 reminder types
+	 */
+	public const REMINDER_TYPES = [
+		self::REMINDER_TYPE_EMAIL,
+		self::REMINDER_TYPE_DISPLAY,
+		self::REMINDER_TYPE_AUDIO
+	];
+
+	/**
+	 * ReminderService constructor.
+	 *
+	 * @param Backend $backend
+	 * @param NotificationProviderManager $notificationProviderManager
+	 * @param IUserManager $userManager
+	 * @param IGroupManager $groupManager
+	 * @param CalDavBackend $caldavBackend
+	 * @param ITimeFactory $timeFactory
+	 */
+	public function __construct(Backend $backend,
+								NotificationProviderManager $notificationProviderManager,
+								IUserManager $userManager,
+								IGroupManager $groupManager,
+								CalDavBackend $caldavBackend,
+								ITimeFactory $timeFactory) {
+		$this->backend = $backend;
+		$this->notificationProviderManager = $notificationProviderManager;
+		$this->userManager = $userManager;
+		$this->groupManager = $groupManager;
+		$this->caldavBackend = $caldavBackend;
+		$this->timeFactory = $timeFactory;
+	}
+
+	/**
+	 * Process reminders to activate
+	 *
+	 * @throws NotificationProvider\ProviderNotAvailableException
+	 * @throws NotificationTypeDoesNotExistException
+	 */
+	public function processReminders():void {
+		$reminders = $this->backend->getRemindersToProcess();
+
+		foreach($reminders as $reminder) {
+			$vcalendar = $this->parseCalendarData($reminder['calendardata']);
+			if (!$vcalendar) {
+				$this->backend->removeReminder($reminder['id']);
+				continue;
+			}
+
+			$vevent = $this->getVEventByRecurrenceId($vcalendar, $reminder['recurrence_id'], $reminder['is_recurrence_exception']);
+			if (!$vevent) {
+				$this->backend->removeReminder($reminder['id']);
+				continue;
+			}
+
+			if ($this->wasEventCancelled($vevent)) {
+				$this->deleteOrProcessNext($reminder, $vevent);
+				continue;
+			}
+
+			if (!$this->notificationProviderManager->hasProvider($reminder['type'])) {
+				$this->deleteOrProcessNext($reminder, $vevent);
+				continue;
+			}
+
+			$users = $this->getAllUsersWithWriteAccessToCalendar($reminder['calendar_id']);
+			$user = $this->getUserFromPrincipalURI($reminder['principaluri']);
+			if ($user) {
+				$users[] = $user;
+			}
+
+			$notificationProvider = $this->notificationProviderManager->getProvider($reminder['type']);
+			$notificationProvider->send($vevent, $reminder['displayname'], $users);
+
+			$this->deleteOrProcessNext($reminder, $vevent);
+		}
+	}
+
+	/**
+	 * @param string $action
+	 * @param array $objectData
+	 * @throws VObject\InvalidDataException
+	 */
+	public function onTouchCalendarObject(string $action,
+										  array $objectData):void {
+		// We only support VEvents for now
+		if (strcasecmp($objectData['component'], 'vevent') !== 0) {
+			return;
+		}
+
+		switch($action) {
+			case '\OCA\DAV\CalDAV\CalDavBackend::createCalendarObject':
+				$this->onCalendarObjectCreate($objectData);
+				break;
+
+			case '\OCA\DAV\CalDAV\CalDavBackend::updateCalendarObject':
+				$this->onCalendarObjectEdit($objectData);
+				break;
+
+			case '\OCA\DAV\CalDAV\CalDavBackend::deleteCalendarObject':
+				$this->onCalendarObjectDelete($objectData);
+				break;
+
+			default:
+				break;
+		}
+	}
+
+	/**
+	 * @param array $objectData
+	 */
+	private function onCalendarObjectCreate(array $objectData):void {
+		/** @var VObject\Component\VCalendar $vcalendar */
+		$vcalendar = $this->parseCalendarData($objectData['calendardata']);
+		if (!$vcalendar) {
+			return;
+		}
+
+		$vevents = $this->getAllVEventsFromVCalendar($vcalendar);
+		if (count($vevents) === 0) {
+			return;
+		}
+
+		$uid = (string) $vevents[0]->UID;
+		$recurrenceExceptions = $this->getRecurrenceExceptionFromListOfVEvents($vevents);
+		$masterItem = $this->getMasterItemFromListOfVEvents($vevents);
+		$now = $this->timeFactory->getDateTime();
+		$isRecurring = $masterItem ? $this->isRecurring($masterItem) : false;
+
+		foreach($recurrenceExceptions as $recurrenceException) {
+			$eventHash = $this->getEventHash($recurrenceException);
+
+			foreach($recurrenceException->VALARM as $valarm) {
+				/** @var VAlarm $valarm */
+				$alarmHash = $this->getAlarmHash($valarm);
+				$triggerTime = $valarm->getEffectiveTriggerTime();
+				$diff = $now->diff($triggerTime);
+				if ($diff->invert === 1) {
+					continue;
+				}
+
+				$alarms = $this->getRemindersForVAlarm($valarm, $objectData,
+					$eventHash, $alarmHash, true, true);
+				$this->writeRemindersToDatabase($alarms);
+			}
+		}
+
+		if ($masterItem) {
+			$processedAlarms = [];
+			$masterAlarms = [];
+			$masterHash = $this->getEventHash($masterItem);
+
+			foreach($masterItem->VALARM as $valarm) {
+				$masterAlarms[] = $this->getAlarmHash($valarm);
+			}
+
+			try {
+				$iterator = new EventIterator($vevents, $uid);
+			} catch (NoInstancesException $e) {
+				// This event is recurring, but it doesn't have a single
+				// instance. We are skipping this event from the output
+				// entirely.
+				return;
+			}
+
+			while($iterator->valid() && count($processedAlarms) < count($masterAlarms)) {
+				$event = $iterator->getEventObject();
+
+				// Recurrence-exceptions are handled separately, so just ignore them here
+				if (\in_array($event, $recurrenceExceptions, true)) {
+					$iterator->next();
+					continue;
+				}
+
+				foreach($event->VALARM as $valarm) {
+					/** @var VAlarm $valarm */
+					$alarmHash = $this->getAlarmHash($valarm);
+					if (\in_array($alarmHash, $processedAlarms, true)) {
+						continue;
+					}
+
+					if (!\in_array((string) $valarm->ACTION, self::REMINDER_TYPES, true)) {
+						// Action allows x-name, we don't insert reminders
+						// into the database if they are not standard
+						$processedAlarms[] = $alarmHash;
+						continue;
+					}
+
+					$triggerTime = $valarm->getEffectiveTriggerTime();
+
+					// If effective trigger time is in the past
+					// just skip and generate for next event
+					$diff = $now->diff($triggerTime);
+					if ($diff->invert === 1) {
+						// If an absolute alarm is in the past,
+						// just add it to processedAlarms, so
+						// we don't extend till eternity
+						if (!$this->isAlarmRelative($valarm)) {
+							$processedAlarms[] = $alarmHash;
+						}
+
+						continue;
+					}
+
+					$alarms = $this->getRemindersForVAlarm($valarm, $objectData, $masterHash, $alarmHash, $isRecurring, false);
+					$this->writeRemindersToDatabase($alarms);
+					$processedAlarms[] = $alarmHash;
+				}
+
+				$iterator->next();
+			}
+		}
+	}
+
+	/**
+	 * @param array $objectData
+	 */
+	private function onCalendarObjectEdit(array $objectData):void {
+		// TODO - this can be vastly improved
+		//  - get cached reminders
+		//  - ...
+
+		$this->onCalendarObjectDelete($objectData);
+		$this->onCalendarObjectCreate($objectData);
+	}
+
+	/**
+	 * @param array $objectData
+	 */
+	private function onCalendarObjectDelete(array $objectData):void {
+		$this->backend->cleanRemindersForEvent((int) $objectData['id']);
+	}
+
+	/**
+	 * @param VAlarm $valarm
+	 * @param array $objectData
+	 * @param string|null $eventHash
+	 * @param string|null $alarmHash
+	 * @param bool $isRecurring
+	 * @param bool $isRecurrenceException
+	 * @return array
+	 */
+	private function getRemindersForVAlarm(VAlarm $valarm,
+										   array $objectData,
+										   string $eventHash=null,
+										   string $alarmHash=null,
+										   bool $isRecurring=false,
+										   bool $isRecurrenceException=false):array {
+		if ($eventHash === null) {
+			$eventHash = $this->getEventHash($valarm->parent);
+		}
+		if ($alarmHash === null) {
+			$alarmHash = $this->getAlarmHash($valarm);
+		}
+
+		$recurrenceId = $this->getEffectiveRecurrenceIdOfVEvent($valarm->parent);
+		$isRelative = $this->isAlarmRelative($valarm);
+		/** @var DateTimeImmutable $notificationDate */
+		$notificationDate = $valarm->getEffectiveTriggerTime();
+		$clonedNotificationDate = new \DateTime('now', $notificationDate->getTimezone());
+		$clonedNotificationDate->setTimestamp($notificationDate->getTimestamp());
+
+		$alarms = [];
+
+		$alarms[] = [
+			'calendar_id' => $objectData['calendarid'],
+			'object_id' => $objectData['id'],
+			'uid' => (string) $valarm->parent->UID,
+			'is_recurring' => $isRecurring,
+			'recurrence_id' => $recurrenceId,
+			'is_recurrence_exception' => $isRecurrenceException,
+			'event_hash' => $eventHash,
+			'alarm_hash' => $alarmHash,
+			'type' => (string) $valarm->ACTION,
+			'is_relative' => $isRelative,
+			'notification_date' => $notificationDate->getTimestamp(),
+			'is_repeat_based' => false,
+		];
+
+		$repeat = isset($valarm->REPEAT) ? (int) $valarm->REPEAT->getValue() : 0;
+		for($i = 0; $i < $repeat; $i++) {
+			if ($valarm->DURATION === null) {
+				continue;
+			}
+
+			$clonedNotificationDate->add($valarm->DURATION->getDateInterval());
+			$alarms[] = [
+				'calendar_id' => $objectData['calendarid'],
+				'object_id' => $objectData['id'],
+				'uid' => (string) $valarm->parent->UID,
+				'is_recurring' => $isRecurring,
+				'recurrence_id' => $recurrenceId,
+				'is_recurrence_exception' => $isRecurrenceException,
+				'event_hash' => $eventHash,
+				'alarm_hash' => $alarmHash,
+				'type' => (string) $valarm->ACTION,
+				'is_relative' => $isRelative,
+				'notification_date' => $clonedNotificationDate->getTimestamp(),
+				'is_repeat_based' => true,
+			];
+		}
+
+		return $alarms;
+	}
+
+	/**
+	 * @param array $reminders
+	 */
+	private function writeRemindersToDatabase(array $reminders): void {
+		foreach($reminders as $reminder) {
+			$this->backend->insertReminder(
+				(int) $reminder['calendar_id'],
+				(int) $reminder['object_id'],
+				$reminder['uid'],
+				$reminder['is_recurring'],
+				(int) $reminder['recurrence_id'],
+				$reminder['is_recurrence_exception'],
+				$reminder['event_hash'],
+				$reminder['alarm_hash'],
+				$reminder['type'],
+				$reminder['is_relative'],
+				(int) $reminder['notification_date'],
+				$reminder['is_repeat_based']
+			);
+		}
+	}
+
+	/**
+	 * @param array $reminder
+	 * @param VEvent $vevent
+	 */
+	private function deleteOrProcessNext(array $reminder,
+										 VObject\Component\VEvent $vevent):void {
+		if ($reminder['is_repeat_based'] ||
+			!$reminder['is_recurring'] ||
+			!$reminder['is_relative'] ||
+			$reminder['is_recurrence_exception']) {
+
+			$this->backend->removeReminder($reminder['id']);
+			return;
+		}
+
+		$vevents = $this->getAllVEventsFromVCalendar($vevent->parent);
+		$recurrenceExceptions = $this->getRecurrenceExceptionFromListOfVEvents($vevents);
+		$now = $this->timeFactory->getDateTime();
+
+		try {
+			$iterator = new EventIterator($vevents, $reminder['uid']);
+		} catch (NoInstancesException $e) {
+			// This event is recurring, but it doesn't have a single
+			// instance. We are skipping this event from the output
+			// entirely.
+			return;
+		}
+
+		while($iterator->valid()) {
+			$event = $iterator->getEventObject();
+
+			// Recurrence-exceptions are handled separately, so just ignore them here
+			if (\in_array($event, $recurrenceExceptions, true)) {
+				$iterator->next();
+				continue;
+			}
+
+			$recurrenceId = $this->getEffectiveRecurrenceIdOfVEvent($event);
+			if ($reminder['recurrence_id'] >= $recurrenceId) {
+				$iterator->next();
+				continue;
+			}
+
+			foreach($event->VALARM as $valarm) {
+				/** @var VAlarm $valarm */
+				$alarmHash = $this->getAlarmHash($valarm);
+				if ($alarmHash !== $reminder['alarm_hash']) {
+					continue;
+				}
+
+				$triggerTime = $valarm->getEffectiveTriggerTime();
+
+				// If effective trigger time is in the past
+				// just skip and generate for next event
+				$diff = $now->diff($triggerTime);
+				if ($diff->invert === 1) {
+					continue;
+				}
+
+				$this->backend->removeReminder($reminder['id']);
+				$alarms = $this->getRemindersForVAlarm($valarm, [
+					'calendarid' => $reminder['calendar_id'],
+					'id' => $reminder['object_id'],
+				], $reminder['event_hash'], $alarmHash, true, false);
+				$this->writeRemindersToDatabase($alarms);
+
+				// Abort generating reminders after creating one successfully
+				return;
+			}
+
+			$iterator->next();
+		}
+
+		$this->backend->removeReminder($reminder['id']);
+	}
+
+	/**
+	 * @param int $calendarId
+	 * @return IUser[]
+	 */
+	private function getAllUsersWithWriteAccessToCalendar(int $calendarId):array {
+		$shares = $this->caldavBackend->getShares($calendarId);
+
+		$users = [];
+		$userIds = [];
+		$groups = [];
+		foreach ($shares as $share) {
+			// Only consider writable shares
+			if ($share['readOnly']) {
+				continue;
+			}
+
+			$principal = explode('/', $share['{http://owncloud.org/ns}principal']);
+			if ($principal[1] === 'users') {
+				$user = $this->userManager->get($principal[2]);
+				if ($user) {
+					$users[] = $user;
+					$userIds[] = $principal[2];
+				}
+			} else if ($principal[1] === 'groups') {
+				$groups[] = $principal[2];
+			}
+		}
+
+		foreach ($groups as $gid) {
+			$group = $this->groupManager->get($gid);
+			if ($group instanceof IGroup) {
+				foreach ($group->getUsers() as $user) {
+					if (!\in_array($user->getUID(), $userIds, true)) {
+						$users[] = $user;
+						$userIds[] = $user->getUID();
+					}
+				}
+			}
+		}
+
+		return $users;
+	}
+
+	/**
+	 * Gets a hash of the event.
+	 * If the hash changes, we have to update all relative alarms.
+	 *
+	 * @param VEvent $vevent
+	 * @return string
+	 */
+	private function getEventHash(VEvent $vevent):string {
+		$properties = [
+			(string) $vevent->DTSTART->serialize(),
+		];
+
+		if ($vevent->DTEND) {
+			$properties[] = (string) $vevent->DTEND->serialize();
+		}
+		if ($vevent->DURATION) {
+			$properties[] = (string) $vevent->DURATION->serialize();
+		}
+		if ($vevent->{'RECURRENCE-ID'}) {
+			$properties[] = (string) $vevent->{'RECURRENCE-ID'}->serialize();
+		}
+		if ($vevent->RRULE) {
+			$properties[] = (string) $vevent->RRULE->serialize();
+		}
+		if ($vevent->EXDATE) {
+			$properties[] = (string) $vevent->EXDATE->serialize();
+		}
+		if ($vevent->RDATE) {
+			$properties[] = (string) $vevent->RDATE->serialize();
+		}
+
+		return md5(implode('::', $properties));
+	}
+
+	/**
+	 * Gets a hash of the alarm.
+	 * If the hash changes, we have to update oc_dav_reminders.
+	 *
+	 * @param VAlarm $valarm
+	 * @return string
+	 */
+	private function getAlarmHash(VAlarm $valarm):string {
+		$properties = [
+			(string) $valarm->ACTION->serialize(),
+			(string) $valarm->TRIGGER->serialize(),
+		];
+
+		if ($valarm->DURATION) {
+			$properties[] = (string) $valarm->DURATION->serialize();
+		}
+		if ($valarm->REPEAT) {
+			$properties[] = (string) $valarm->REPEAT->serialize();
+		}
+
+		return md5(implode('::', $properties));
+	}
+
+	/**
+	 * @param VObject\Component\VCalendar $vcalendar
+	 * @param int $recurrenceId
+	 * @param bool $isRecurrenceException
+	 * @return VEvent|null
+	 */
+	private function getVEventByRecurrenceId(VObject\Component\VCalendar $vcalendar,
+											 int $recurrenceId,
+											 bool $isRecurrenceException):?VEvent {
+		$vevents = $this->getAllVEventsFromVCalendar($vcalendar);
+		if (count($vevents) === 0) {
+			return null;
+		}
+
+		$uid = (string) $vevents[0]->UID;
+		$recurrenceExceptions = $this->getRecurrenceExceptionFromListOfVEvents($vevents);
+		$masterItem = $this->getMasterItemFromListOfVEvents($vevents);
+
+		// Handle recurrence-exceptions first, because recurrence-expansion is expensive
+		if ($isRecurrenceException) {
+			foreach($recurrenceExceptions as $recurrenceException) {
+				if ($this->getEffectiveRecurrenceIdOfVEvent($recurrenceException) === $recurrenceId) {
+					return $recurrenceException;
+				}
+			}
+
+			return null;
+		}
+
+		if ($masterItem) {
+			try {
+				$iterator = new EventIterator($vevents, $uid);
+			} catch (NoInstancesException $e) {
+				// This event is recurring, but it doesn't have a single
+				// instance. We are skipping this event from the output
+				// entirely.
+				return null;
+			}
+
+			while ($iterator->valid()) {
+				$event = $iterator->getEventObject();
+
+				// Recurrence-exceptions are handled separately, so just ignore them here
+				if (\in_array($event, $recurrenceExceptions, true)) {
+					$iterator->next();
+					continue;
+				}
+
+				if ($this->getEffectiveRecurrenceIdOfVEvent($event) === $recurrenceId) {
+					return $event;
+				}
+
+				$iterator->next();
+			}
+		}
+
+		return null;
+	}
+
+	/**
+	 * @param VEvent $vevent
+	 * @return string
+	 */
+	private function getStatusOfEvent(VEvent $vevent):string {
+		if ($vevent->STATUS) {
+			return (string) $vevent->STATUS;
+		}
+
+		// Doesn't say so in the standard,
+		// but we consider events without a status
+		// to be confirmed
+		return 'CONFIRMED';
+	}
+
+	/**
+	 * @param VObject\Component\VEvent $vevent
+	 * @return bool
+	 */
+	private function wasEventCancelled(VObject\Component\VEvent $vevent):bool {
+		return $this->getStatusOfEvent($vevent) === 'CANCELLED';
+	}
+
+	/**
+	 * @param string $calendarData
+	 * @return VObject\Component\VCalendar|null
+	 */
+	private function parseCalendarData(string $calendarData):?VObject\Component\VCalendar {
+		try {
+			return VObject\Reader::read($calendarData,
+				VObject\Reader::OPTION_FORGIVING);
+		} catch(ParseException $ex) {
+			return null;
+		}
+	}
+
+	/**
+	 * @param string $principalUri
+	 * @return IUser|null
+	 */
+	private function getUserFromPrincipalURI(string $principalUri):?IUser {
+		if (!$principalUri) {
+			return null;
+		}
+
+		if (stripos($principalUri, 'principals/users/') !== 0) {
+			return null;
+		}
+
+		$userId = substr($principalUri, 17);
+		return $this->userManager->get($userId);
+	}
+
+	/**
+	 * @param VObject\Component\VCalendar $vcalendar
+	 * @return VObject\Component\VEvent[]
+	 */
+	private function getAllVEventsFromVCalendar(VObject\Component\VCalendar $vcalendar):array {
+		$vevents = [];
+
+		foreach($vcalendar->children() as $child) {
+			if (!($child instanceof VObject\Component)) {
+				continue;
+			}
+
+			if ($child->name !== 'VEVENT') {
+				continue;
+			}
+
+			$vevents[] = $child;
+		}
+
+		return $vevents;
+	}
+
+	/**
+	 * @param array $vevents
+	 * @return VObject\Component\VEvent[]
+	 */
+	private function getRecurrenceExceptionFromListOfVEvents(array $vevents):array {
+		return array_values(array_filter($vevents, function(VEvent $vevent) {
+			return $vevent->{'RECURRENCE-ID'} !== null;
+		}));
+	}
+
+	/**
+	 * @param array $vevents
+	 * @return VEvent|null
+	 */
+	private function getMasterItemFromListOfVEvents(array $vevents):?VEvent {
+		$elements = array_values(array_filter($vevents, function(VEvent $vevent) {
+			return $vevent->{'RECURRENCE-ID'} === null;
+		}));
+
+		if (count($elements) === 0) {
+			return null;
+		}
+		if (count($elements) > 1) {
+			throw new \TypeError('Multiple master objects');
+		}
+
+		return $elements[0];
+	}
+
+	/**
+	 * @param VAlarm $valarm
+	 * @return bool
+	 */
+	private function isAlarmRelative(VAlarm $valarm):bool {
+		$trigger = $valarm->TRIGGER;
+		return $trigger instanceof VObject\Property\ICalendar\Duration;
+	}
+
+	/**
+	 * @param VEvent $vevent
+	 * @return int
+	 */
+	private function getEffectiveRecurrenceIdOfVEvent(VEvent $vevent):int {
+		if (isset($vevent->{'RECURRENCE-ID'})) {
+			return $vevent->{'RECURRENCE-ID'}->getDateTime()->getTimestamp();
+		}
+
+		return $vevent->DTSTART->getDateTime()->getTimestamp();
+	}
+
+	/**
+	 * @param VEvent $vevent
+	 * @return bool
+	 */
+	private function isRecurring(VEvent $vevent):bool {
+		return isset($vevent->RRULE) || isset($vevent->RDATE);
+	}
+}
diff --git a/apps/dav/lib/Command/SendEventReminders.php b/apps/dav/lib/Command/SendEventReminders.php
new file mode 100644
index 00000000000..93477cb0f72
--- /dev/null
+++ b/apps/dav/lib/Command/SendEventReminders.php
@@ -0,0 +1,82 @@
+<?php
+/**
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+namespace OCA\DAV\Command;
+
+use OCA\DAV\CalDAV\Reminder\ReminderService;
+use OCP\IConfig;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+/**
+ * Class SendEventReminders
+ *
+ * @package OCA\DAV\Command
+ */
+class SendEventReminders extends Command {
+
+	/** @var ReminderService */
+	protected $reminderService;
+
+	/** @var IConfig */
+	protected $config;
+
+	/**
+	 * @param ReminderService $reminderService
+	 * @param IConfig $config
+	 */
+	public function __construct(ReminderService $reminderService,
+								IConfig $config) {
+		parent::__construct();
+		$this->reminderService = $reminderService;
+		$this->config = $config;
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	protected function configure():void {
+		$this
+			->setName('dav:send-event-reminders')
+			->setDescription('Sends event reminders');
+	}
+
+	/**
+	 * @param InputInterface $input
+	 * @param OutputInterface $output
+	 */
+	protected function execute(InputInterface $input, OutputInterface $output):void {
+		if ($this->config->getAppValue('dav', 'sendEventReminders', 'yes') !== 'yes') {
+			$output->writeln('<error>Sending event reminders disabled!</error>');
+			$output->writeln('<info>Please run "php occ config:app:set dav sendEventReminders --value yes"');
+			return;
+		}
+
+		if ($this->config->getAppValue('dav', 'sendEventRemindersMode', 'backgroundjob') !== 'occ') {
+			$output->writeln('<error>Sending event reminders mode set to background-job!</error>');
+			$output->writeln('<info>Please run "php occ config:app:set dav sendEventRemindersMode --value occ"');
+			return;
+		}
+
+		$this->reminderService->processReminders();
+	}
+}
diff --git a/apps/dav/lib/Migration/RegisterBuildReminderIndexBackgroundJob.php b/apps/dav/lib/Migration/RegisterBuildReminderIndexBackgroundJob.php
new file mode 100644
index 00000000000..c7a1cf63ab9
--- /dev/null
+++ b/apps/dav/lib/Migration/RegisterBuildReminderIndexBackgroundJob.php
@@ -0,0 +1,96 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright 2019 Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\Migration;
+
+use OCA\DAV\BackgroundJob\BuildReminderIndexBackgroundJob;
+use OCP\BackgroundJob\IJobList;
+use OCP\IConfig;
+use OCP\IDBConnection;
+use OCP\Migration\IOutput;
+use OCP\Migration\IRepairStep;
+
+/**
+ * Class RegisterBuildReminderIndexBackgroundJob
+ *
+ * @package OCA\DAV\Migration
+ */
+class RegisterBuildReminderIndexBackgroundJob implements IRepairStep {
+
+	/** @var IDBConnection */
+	private $db;
+
+	/** @var IJobList */
+	private $jobList;
+
+	/** @var IConfig */
+	private $config;
+
+	/** @var string */
+	private const CONFIG_KEY = 'buildCalendarReminderIndex';
+
+	/**
+	 * @param IDBConnection $db
+	 * @param IJobList $jobList
+	 * @param IConfig $config
+	 */
+	public function __construct(IDBConnection $db,
+								IJobList $jobList,
+								IConfig $config) {
+		$this->db = $db;
+		$this->jobList = $jobList;
+		$this->config = $config;
+	}
+
+	/**
+	 * @return string
+	 */
+	public function getName() {
+		return 'Registering building of calendar reminder index as background job';
+	}
+
+	/**
+	 * @param IOutput $output
+	 */
+	public function run(IOutput $output) {
+		// only run once
+		if ($this->config->getAppValue('dav', self::CONFIG_KEY) === 'yes') {
+			$output->info('Repair step already executed');
+			return;
+		}
+
+		$query = $this->db->getQueryBuilder();
+		$query->select($query->createFunction('MAX(' . $query->getColumnName('id') . ')'))
+			->from('calendarobjects');
+		$maxId = (int)$query->execute()->fetchColumn();
+
+		$output->info('Add background job');
+		$this->jobList->add(BuildReminderIndexBackgroundJob::class, [
+			'offset' => 0,
+			'stopAt' => $maxId
+		]);
+
+		// if all were done, no need to redo the repair during next upgrade
+		$this->config->setAppValue('dav', self::CONFIG_KEY, 'yes');
+	}
+}
\ No newline at end of file
diff --git a/apps/dav/lib/Migration/Version1012Date20190808122342.php b/apps/dav/lib/Migration/Version1012Date20190808122342.php
new file mode 100644
index 00000000000..4aa768e705d
--- /dev/null
+++ b/apps/dav/lib/Migration/Version1012Date20190808122342.php
@@ -0,0 +1,116 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright 2019, Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\Migration;
+
+use Doctrine\DBAL\Types\Type;
+use OCP\DB\ISchemaWrapper;
+use OCP\Migration\SimpleMigrationStep;
+use OCP\Migration\IOutput;
+
+/**
+ * Auto-generated migration step: Please modify to your needs!
+ */
+class Version1012Date20190808122342 extends SimpleMigrationStep {
+
+	/**
+	 * @param IOutput $output
+	 * @param \Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 * @return null|ISchemaWrapper
+	 * @since 13.0.0
+	 */
+	public function changeSchema(IOutput $output,
+								 \Closure $schemaClosure,
+								 array $options):?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		if (!$schema->hasTable('calendar_reminders')) {
+			$table = $schema->createTable('calendar_reminders');
+
+			$table->addColumn('id', Type::BIGINT, [
+				'autoincrement' => true,
+				'notnull' => true,
+				'length' => 11,
+				'unsigned' => true,
+			]);
+			$table->addColumn('calendar_id', Type::BIGINT, [
+				'notnull' => true,
+				'length' => 11,
+			]);
+			$table->addColumn('object_id', Type::BIGINT, [
+				'notnull' => true,
+				'length' => 11,
+			]);
+			$table->addColumn('is_recurring', Type::SMALLINT, [
+				'notnull' => true,
+				'length' => 1,
+			]);
+			$table->addColumn('uid', Type::STRING, [
+				'notnull' => true,
+				'length' => 255,
+			]);
+			$table->addColumn('recurrence_id', Type::BIGINT, [
+				'notnull' => false,
+				'length' => 11,
+				'unsigned' => true,
+			]);
+			$table->addColumn('is_recurrence_exception', Type::SMALLINT, [
+				'notnull' => true,
+				'length' => 1,
+			]);
+			$table->addColumn('event_hash', Type::STRING, [
+				'notnull' => true,
+				'length' => 255,
+			]);
+			$table->addColumn('alarm_hash', Type::STRING, [
+				'notnull' => true,
+				'length' => 255,
+			]);
+			$table->addColumn('type', Type::STRING, [
+				'notnull' => true,
+				'length' => 255,
+			]);
+			$table->addColumn('is_relative', Type::SMALLINT, [
+				'notnull' => true,
+				'length' => 1,
+			]);
+			$table->addColumn('notification_date', Type::BIGINT, [
+				'notnull' => true,
+				'length' => 11,
+				'unsigned' => true,
+			]);
+			$table->addColumn('is_repeat_based', Type::SMALLINT, [
+				'notnull' => true,
+				'length' => 1,
+			]);
+
+			$table->setPrimaryKey(['id']);
+			$table->addIndex(['object_id'], 'calendar_reminder_objid');
+			$table->addIndex(['uid', 'recurrence_id'], 'calendar_reminder_uidrec');
+
+			return $schema;
+		}
+	}
+}
diff --git a/apps/dav/lib/Settings/CalDAVSettings.php b/apps/dav/lib/Settings/CalDAVSettings.php
index f38143b5b4e..958c463b1d3 100644
--- a/apps/dav/lib/Settings/CalDAVSettings.php
+++ b/apps/dav/lib/Settings/CalDAVSettings.php
@@ -48,6 +48,7 @@ class CalDAVSettings implements ISettings {
 		$parameters = [
 			'send_invitations' => $this->config->getAppValue('dav', 'sendInvitations', 'yes'),
 			'generate_birthday_calendar' => $this->config->getAppValue('dav', 'generateBirthdayCalendar', 'yes'),
+			'send_reminders_notifications' => $this->config->getAppValue('dav', 'sendEventReminders', 'yes'),
 		];
 
 		return new TemplateResponse('dav', 'settings-admin-caldav', $parameters);
diff --git a/apps/dav/templates/settings-admin-caldav.php b/apps/dav/templates/settings-admin-caldav.php
index 87b159923d2..ba55a884702 100644
--- a/apps/dav/templates/settings-admin-caldav.php
+++ b/apps/dav/templates/settings-admin-caldav.php
@@ -72,4 +72,25 @@ script('dav', [
 		<em><?php p($l->t('Birthday calendars will be generated by a background job.')); ?></em><br>
 		<em><?php p($l->t('Hence they will not be available immediately after enabling but will show up after some time.')); ?></em>
 	</p>
+	<p>
+		<input type="checkbox" name="caldav_send_reminders_notifications" id="caldavSendRemindersNotifications" class="checkbox"
+			<?php ($_['send_reminders_notifications'] === 'yes') ? print_unescaped('checked="checked"') : null ?>/>
+		<label for="caldavSendRemindersNotifications"><?php p($l->t('Send notifications for events')); ?></label>
+		<br>
+		<em>
+			<?php print_unescaped(str_replace(
+				[
+					'{emailopen}',
+					'{linkclose}',
+				],
+				[
+					'<a href="../admin#mail_general_settings">',
+					'</a>',
+				],
+				$l->t('Please make sure to properly set up {emailopen}the email server{linkclose}.')
+			)); ?>
+		</em>
+		<br>
+		<em><?php p($l->t('Notifications will be send through background jobs, so these need to happen often enough.')); ?></em>
+	</p>
 </form>
diff --git a/apps/dav/tests/unit/BackgroundJob/EventReminderJobTest.php b/apps/dav/tests/unit/BackgroundJob/EventReminderJobTest.php
new file mode 100644
index 00000000000..c3b4b7e54c2
--- /dev/null
+++ b/apps/dav/tests/unit/BackgroundJob/EventReminderJobTest.php
@@ -0,0 +1,93 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright 2018, Thomas Citharel <tcit@tcit.fr>
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ *
+ * @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\Tests\unit\BackgroundJob;
+
+use OCA\DAV\BackgroundJob\EventReminderJob;
+use OCA\DAV\CalDAV\Reminder\ReminderService;
+use OCP\IConfig;
+use Test\TestCase;
+
+class EventReminderJobTest extends TestCase {
+
+	/** @var ReminderService|\PHPUnit\Framework\MockObject\MockObject */
+	private $reminderService;
+
+	/** @var IConfig|\PHPUnit\Framework\MockObject\MockObject */
+	private $config;
+
+	/** @var EventReminderJob|\PHPUnit\Framework\MockObject\MockObject */
+	private $backgroundJob;
+
+	protected function setUp() {
+		parent::setUp();
+
+		$this->reminderService = $this->createMock(ReminderService::class);
+		$this->config = $this->createMock(IConfig::class);
+
+		$this->backgroundJob = new EventReminderJob($this->reminderService, $this->config);
+	}
+
+	public function data(): array
+	{
+		return [
+			[true, true, true],
+			[true, false, false],
+			[false, true, false],
+			[false, false, false],
+		];
+	}
+
+	/**
+	 * @dataProvider data
+	 *
+	 * @param bool $sendEventReminders
+	 * @param bool $sendEventRemindersMode
+	 * @param bool $expectCall
+	 */
+	public function testRun(bool $sendEventReminders, bool $sendEventRemindersMode, bool $expectCall): void {
+		$this->config->expects($this->at(0))
+			->method('getAppValue')
+			->with('dav', 'sendEventReminders', 'yes')
+			->willReturn($sendEventReminders ? 'yes' : 'no');
+
+		if ($sendEventReminders) {
+			$this->config->expects($this->at(1))
+				->method('getAppValue')
+				->with('dav', 'sendEventRemindersMode', 'backgroundjob')
+				->willReturn($sendEventRemindersMode ? 'backgroundjob' : 'cron');
+
+		}
+
+		if ($expectCall) {
+			$this->reminderService->expects($this->once())
+				->method('processReminders');
+		} else {
+			$this->reminderService->expects($this->never())
+				->method('processReminders');
+		}
+
+		$this->backgroundJob->run([]);
+	}
+}
diff --git a/apps/dav/tests/unit/CalDAV/Reminder/BackendTest.php b/apps/dav/tests/unit/CalDAV/Reminder/BackendTest.php
new file mode 100644
index 00000000000..71453ac73a3
--- /dev/null
+++ b/apps/dav/tests/unit/CalDAV/Reminder/BackendTest.php
@@ -0,0 +1,397 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+namespace OCA\DAV\Tests\unit\CalDAV\Reminder;
+
+use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCA\DAV\CalDAV\Reminder\Backend as ReminderBackend;
+use Test\TestCase;
+
+class BackendTest extends TestCase {
+
+	/**
+	 * Reminder Backend
+	 *
+	 * @var ReminderBackend|\PHPUnit\Framework\MockObject\MockObject
+	 */
+	private $reminderBackend;
+
+	/** @var ITimeFactory|\PHPUnit\Framework\MockObject\MockObject */
+	private $timeFactory;
+
+	public function setUp() {
+		parent::setUp();
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$query->delete('calendar_reminders')->execute();
+		$query->delete('calendarobjects')->execute();
+		$query->delete('calendars')->execute();
+
+		$this->timeFactory = $this->createMock(ITimeFactory::class);
+		$this->reminderBackend = new ReminderBackend(self::$realDatabase, $this->timeFactory);
+
+		$this->createRemindersTestSet();
+	}
+
+	protected function tearDown() {
+		$query = self::$realDatabase->getQueryBuilder();
+		$query->delete('calendar_reminders')->execute();
+		$query->delete('calendarobjects')->execute();
+		$query->delete('calendars')->execute();
+	}
+
+
+	public function testCleanRemindersForEvent(): void {
+		$query = self::$realDatabase->getQueryBuilder();
+		$rows = $query->select('*')
+			->from('calendar_reminders')
+			->execute()
+			->fetchAll();
+
+		$this->assertCount(4, $rows);
+
+		$this->reminderBackend->cleanRemindersForEvent(1);
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$rows = $query->select('*')
+			->from('calendar_reminders')
+			->execute()
+			->fetchAll();
+
+		$this->assertCount(2, $rows);
+	}
+
+	public function testCleanRemindersForCalendar(): void {
+		$query = self::$realDatabase->getQueryBuilder();
+		$rows = $query->select('*')
+			->from('calendar_reminders')
+			->execute()
+			->fetchAll();
+
+		$this->assertCount(4, $rows);
+
+		$this->reminderBackend->cleanRemindersForCalendar(1);
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$rows = $query->select('*')
+			->from('calendar_reminders')
+			->execute()
+			->fetchAll();
+
+		$this->assertCount(1, $rows);
+	}
+
+	public function testRemoveReminder(): void {
+		$query = self::$realDatabase->getQueryBuilder();
+		$rows = $query->select('*')
+			->from('calendar_reminders')
+			->execute()
+			->fetchAll();
+
+		$this->assertCount(4, $rows);
+
+		$this->reminderBackend->removeReminder((int) $rows[3]['id']);
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$rows = $query->select('*')
+			->from('calendar_reminders')
+			->execute()
+			->fetchAll();
+
+		$this->assertCount(3, $rows);
+	}
+
+	public function testGetRemindersToProcess(): void {
+		$this->timeFactory->expects($this->exactly(1))
+			->method('getTime')
+			->with()
+			->willReturn(123457);
+
+		$rows = $this->reminderBackend->getRemindersToProcess();
+
+		$this->assertCount(2, $rows);
+		unset($rows[0]['id']);
+		unset($rows[1]['id']);
+
+		$this->assertEquals($rows[0], [
+			'calendar_id' => 1,
+			'object_id' => 1,
+			'uid' => 'asd',
+			'is_recurring' => false,
+			'recurrence_id' => 123458,
+			'is_recurrence_exception' => false,
+			'event_hash' => 'asd123',
+			'alarm_hash' => 'asd567',
+			'type' => 'EMAIL',
+			'is_relative' => true,
+			'notification_date' => 123456,
+			'is_repeat_based' => false,
+			'calendardata' => 'Calendar data 123',
+			'displayname' => 'Displayname 123',
+			'principaluri' => 'principals/users/user001',
+		]);
+		$this->assertEquals($rows[1], [
+			'calendar_id' => 1,
+			'object_id' => 1,
+			'uid' => 'asd',
+			'is_recurring' => false,
+			'recurrence_id' => 123458,
+			'is_recurrence_exception' => false,
+			'event_hash' => 'asd123',
+			'alarm_hash' => 'asd567',
+			'type' => 'AUDIO',
+			'is_relative' => true,
+			'notification_date' => 123456,
+			'is_repeat_based' => false,
+			'calendardata' => 'Calendar data 123',
+			'displayname' => 'Displayname 123',
+			'principaluri' => 'principals/users/user001',
+		]);
+	}
+
+	public function testGetAllScheduledRemindersForEvent(): void {
+		$rows = $this->reminderBackend->getAllScheduledRemindersForEvent(1);
+
+		$this->assertCount(2, $rows);
+		unset($rows[0]['id']);
+		unset($rows[1]['id']);
+
+		$this->assertEquals($rows[0], [
+			'calendar_id' => 1,
+			'object_id' => 1,
+			'uid' => 'asd',
+			'is_recurring' => false,
+			'recurrence_id' => 123458,
+			'is_recurrence_exception' => false,
+			'event_hash' => 'asd123',
+			'alarm_hash' => 'asd567',
+			'type' => 'EMAIL',
+			'is_relative' => true,
+			'notification_date' => 123456,
+			'is_repeat_based' => false,
+		]);
+		$this->assertEquals($rows[1], [
+			'calendar_id' => 1,
+			'object_id' => 1,
+			'uid' => 'asd',
+			'is_recurring' => false,
+			'recurrence_id' => 123458,
+			'is_recurrence_exception' => false,
+			'event_hash' => 'asd123',
+			'alarm_hash' => 'asd567',
+			'type' => 'AUDIO',
+			'is_relative' => true,
+			'notification_date' => 123456,
+			'is_repeat_based' => false,
+		]);
+	}
+
+	public function testInsertReminder(): void {
+		$query = self::$realDatabase->getQueryBuilder();
+		$rows = $query->select('*')
+			->from('calendar_reminders')
+			->execute()
+			->fetchAll();
+
+		$this->assertCount(4, $rows);
+
+		$this->reminderBackend->insertReminder(42, 1337, 'uid99', true, 12345678,
+			true, 'hash99', 'hash42', 'AUDIO', false, 12345670, false);
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$rows = $query->select('*')
+			->from('calendar_reminders')
+			->execute()
+			->fetchAll();
+
+		$this->assertCount(5, $rows);
+
+		unset($rows[4]['id']);
+
+		$this->assertEquals($rows[4], [
+			'calendar_id' => '42',
+			'object_id' => '1337',
+			'is_recurring' => '1',
+			'uid' => 'uid99',
+			'recurrence_id' => '12345678',
+			'is_recurrence_exception' => '1',
+			'event_hash' => 'hash99',
+			'alarm_hash' => 'hash42',
+			'type' => 'AUDIO',
+			'is_relative' => '0',
+			'notification_date' => '12345670',
+			'is_repeat_based' => '0',
+		]);
+	}
+
+	public function testUpdateReminder() {
+		$query = self::$realDatabase->getQueryBuilder();
+		$rows = $query->select('*')
+			->from('calendar_reminders')
+			->execute()
+			->fetchAll();
+
+		$this->assertCount(4, $rows);
+
+		$this->assertEquals($rows[3]['notification_date'], 123600);
+
+		$reminderId = (int)  $rows[3]['id'];
+		$newNotificationDate = 123700;
+
+		$this->reminderBackend->updateReminder($reminderId, $newNotificationDate);
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$row = $query->select('notification_date')
+			->from('calendar_reminders')
+			->where($query->expr()->eq('id', $query->createNamedParameter($reminderId)))
+			->execute()
+			->fetch();
+
+		$this->assertEquals((int) $row['notification_date'], 123700);
+	}
+
+
+	private function createRemindersTestSet(): void {
+		$query = self::$realDatabase->getQueryBuilder();
+		$query->insert('calendars')
+			->values([
+				'id' => $query->createNamedParameter(1),
+				'principaluri' => $query->createNamedParameter('principals/users/user001'),
+				'displayname' => $query->createNamedParameter('Displayname 123'),
+			])
+			->execute();
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$query->insert('calendars')
+			->values([
+				'id' => $query->createNamedParameter(99),
+				'principaluri' => $query->createNamedParameter('principals/users/user002'),
+				'displayname' => $query->createNamedParameter('Displayname 99'),
+			])
+			->execute();
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$query->insert('calendarobjects')
+			->values([
+				'id' => $query->createNamedParameter(1),
+				'calendardata' => $query->createNamedParameter('Calendar data 123'),
+				'calendarid' => $query->createNamedParameter(1),
+				'size' => $query->createNamedParameter(42),
+			])
+			->execute();
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$query->insert('calendarobjects')
+			->values([
+				'id' => $query->createNamedParameter(2),
+				'calendardata' => $query->createNamedParameter('Calendar data 456'),
+				'calendarid' => $query->createNamedParameter(1),
+				'size' => $query->createNamedParameter(42),
+			])
+			->execute();
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$query->insert('calendarobjects')
+			->values([
+				'id' => $query->createNamedParameter(10),
+				'calendardata' => $query->createNamedParameter('Calendar data 789'),
+				'calendarid' => $query->createNamedParameter(99),
+				'size' => $query->createNamedParameter(42),
+			])
+			->execute();
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$query->insert('calendar_reminders')
+			->values([
+				'calendar_id' => $query->createNamedParameter(1),
+				'object_id' => $query->createNamedParameter(1),
+				'uid' => $query->createNamedParameter('asd'),
+				'is_recurring' => $query->createNamedParameter(0),
+				'recurrence_id' => $query->createNamedParameter(123458),
+				'is_recurrence_exception' => $query->createNamedParameter(0),
+				'event_hash' => $query->createNamedParameter('asd123'),
+				'alarm_hash' => $query->createNamedParameter('asd567'),
+				'type' => $query->createNamedParameter('EMAIL'),
+				'is_relative' => $query->createNamedParameter(1),
+				'notification_date' => $query->createNamedParameter(123456),
+				'is_repeat_based' => $query->createNamedParameter(0),
+			])
+			->execute();
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$query->insert('calendar_reminders')
+			->values([
+				'calendar_id' => $query->createNamedParameter(1),
+				'object_id' => $query->createNamedParameter(1),
+				'uid' => $query->createNamedParameter('asd'),
+				'is_recurring' => $query->createNamedParameter(0),
+				'recurrence_id' => $query->createNamedParameter(123458),
+				'is_recurrence_exception' => $query->createNamedParameter(0),
+				'event_hash' => $query->createNamedParameter('asd123'),
+				'alarm_hash' => $query->createNamedParameter('asd567'),
+				'type' => $query->createNamedParameter('AUDIO'),
+				'is_relative' => $query->createNamedParameter(1),
+				'notification_date' => $query->createNamedParameter(123456),
+				'is_repeat_based' => $query->createNamedParameter(0),
+			])
+			->execute();
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$query->insert('calendar_reminders')
+			->values([
+				'calendar_id' => $query->createNamedParameter(1),
+				'object_id' => $query->createNamedParameter(2),
+				'uid' => $query->createNamedParameter('asd'),
+				'is_recurring' => $query->createNamedParameter(0),
+				'recurrence_id' => $query->createNamedParameter(123900),
+				'is_recurrence_exception' => $query->createNamedParameter(0),
+				'event_hash' => $query->createNamedParameter('asd123'),
+				'alarm_hash' => $query->createNamedParameter('asd567'),
+				'type' => $query->createNamedParameter('EMAIL'),
+				'is_relative' => $query->createNamedParameter(1),
+				'notification_date' => $query->createNamedParameter(123499),
+				'is_repeat_based' => $query->createNamedParameter(0),
+			])
+			->execute();
+
+		$query = self::$realDatabase->getQueryBuilder();
+		$query->insert('calendar_reminders')
+			->values([
+				'calendar_id' => $query->createNamedParameter(99),
+				'object_id' => $query->createNamedParameter(10),
+				'uid' => $query->createNamedParameter('asd'),
+				'is_recurring' => $query->createNamedParameter(0),
+				'recurrence_id' => $query->createNamedParameter(123900),
+				'is_recurrence_exception' => $query->createNamedParameter(0),
+				'event_hash' => $query->createNamedParameter('asd123'),
+				'alarm_hash' => $query->createNamedParameter('asd567'),
+				'type' => $query->createNamedParameter('DISPLAY'),
+				'is_relative' => $query->createNamedParameter(1),
+				'notification_date' => $query->createNamedParameter(123600),
+				'is_repeat_based' => $query->createNamedParameter(0),
+			])
+			->execute();
+	}
+}
diff --git a/apps/dav/tests/unit/CalDAV/Reminder/NotificationProvider/AbstractNotificationProviderTest.php b/apps/dav/tests/unit/CalDAV/Reminder/NotificationProvider/AbstractNotificationProviderTest.php
new file mode 100644
index 00000000000..5a8d328ef81
--- /dev/null
+++ b/apps/dav/tests/unit/CalDAV/Reminder/NotificationProvider/AbstractNotificationProviderTest.php
@@ -0,0 +1,89 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+namespace OCA\DAV\Tests\unit\CalDAV\Reminder\NotificationProvider;
+
+use OCA\DAV\CalDAV\Reminder\NotificationProvider\AbstractProvider;
+use OCP\IConfig;
+use OCP\IL10N;
+use OCP\ILogger;
+use OCP\IURLGenerator;
+use OCP\L10N\IFactory as L10NFactory;
+use OCP\IUser;
+use Test\TestCase;
+use Sabre\VObject\Component\VCalendar;
+
+abstract class AbstractNotificationProviderTest extends TestCase {
+
+	/** @var ILogger|\PHPUnit\Framework\MockObject\MockObject */
+	protected $logger;
+
+	/** @var L10NFactory|\PHPUnit\Framework\MockObject\MockObject */
+	protected $l10nFactory;
+
+	/** @var IL10N|\PHPUnit\Framework\MockObject\MockObject */
+	protected $l10n;
+
+	/** @var IURLGenerator|\PHPUnit\Framework\MockObject\MockObject */
+	protected $urlGenerator;
+
+	/** @var IConfig|\PHPUnit\Framework\MockObject\MockObject */
+	protected $config;
+
+	/** @var AbstractProvider|\PHPUnit\Framework\MockObject\MockObject */
+	protected $provider;
+
+	/**
+	 * @var VCalendar
+	 */
+	protected $vcalendar;
+
+	/**
+	 * @var string
+	 */
+	protected $calendarDisplayName;
+
+	/**
+	 * @var IUser|\PHPUnit\Framework\MockObject\MockObject
+	 */
+	protected $user;
+
+	public function setUp() {
+		parent::setUp();
+
+		$this->logger = $this->createMock(ILogger::class);
+		$this->l10nFactory = $this->createMock(L10NFactory::class);
+		$this->l10n = $this->createMock(IL10N::class);
+		$this->urlGenerator = $this->createMock(IURLGenerator::class);
+		$this->config = $this->createMock(IConfig::class);
+
+		$this->vcalendar = new VCalendar();
+		$this->vcalendar->add('VEVENT', [
+			'SUMMARY' => 'Fellowship meeting',
+			'DTSTART' => new \DateTime('2017-01-01 00:00:00+00:00'), // 1483228800,
+			'UID' => 'uid1234',
+		]);
+		$this->calendarDisplayName = 'Personal';
+
+		$this->user = $this->createMock(IUser::class);
+	}
+}
diff --git a/apps/dav/tests/unit/CalDAV/Reminder/NotificationProvider/AudioProviderTest.php b/apps/dav/tests/unit/CalDAV/Reminder/NotificationProvider/AudioProviderTest.php
new file mode 100644
index 00000000000..9938b2f732c
--- /dev/null
+++ b/apps/dav/tests/unit/CalDAV/Reminder/NotificationProvider/AudioProviderTest.php
@@ -0,0 +1,33 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+namespace OCA\DAV\Tests\unit\CalDAV\Reminder\NotificationProvider;
+
+use OCA\DAV\CalDAV\Reminder\NotificationProvider\AudioProvider;
+
+class AudioProviderTest extends PushProviderTest {
+
+	public function testNotificationType():void {
+		$this->assertEquals(AudioProvider::NOTIFICATION_TYPE, 'AUDIO');
+	}
+
+}
\ No newline at end of file
diff --git a/apps/dav/tests/unit/CalDAV/Reminder/NotificationProvider/EmailProviderTest.php b/apps/dav/tests/unit/CalDAV/Reminder/NotificationProvider/EmailProviderTest.php
new file mode 100644
index 00000000000..9bf2957e9f0
--- /dev/null
+++ b/apps/dav/tests/unit/CalDAV/Reminder/NotificationProvider/EmailProviderTest.php
@@ -0,0 +1,546 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+namespace OCA\DAV\Tests\unit\CalDAV\Reminder\NotificationProvider;
+
+use OCA\DAV\CalDAV\Reminder\NotificationProvider\EmailProvider;
+use OCP\IConfig;
+use OCP\IL10N;
+use OCP\ILogger;
+use OCP\IURLGenerator;
+use OCP\L10N\IFactory as L10NFactory;
+use OCP\IUser;
+use OCP\Mail\IEMailTemplate;
+use OCP\Mail\IMailer;
+use OCP\Mail\IAttachment;
+use OCP\Mail\IMessage;
+use Sabre\VObject\Component\VCalendar;
+use Test\TestCase;
+
+class EmailProviderTest extends AbstractNotificationProviderTest {
+
+	const USER_EMAIL = 'frodo@hobb.it';
+
+	/** @var ILogger|\PHPUnit\Framework\MockObject\MockObject */
+	protected $logger;
+
+	/** @var L10NFactory|\PHPUnit\Framework\MockObject\MockObject */
+	protected $l10nFactory;
+
+	/** @var IL10N|\PHPUnit\Framework\MockObject\MockObject */
+	protected $l10n;
+
+	/** @var IURLGenerator|\PHPUnit\Framework\MockObject\MockObject */
+	protected $urlGenerator;
+
+	/** @var IConfig|\PHPUnit\Framework\MockObject\MockObject */
+	protected $config;
+
+	/** @var IMailer|\PHPUnit\Framework\MockObject\MockObject */
+	private $mailer;
+
+	public function setUp() {
+		parent::setUp();
+
+		$this->mailer = $this->createMock(IMailer::class);
+
+		$this->provider = new EmailProvider(
+			$this->config,
+			$this->mailer,
+			$this->logger,
+			$this->l10nFactory,
+			$this->urlGenerator
+		);
+	}
+
+	public function testSendWithoutAttendees():void {
+		$user1 = $this->createMock(IUser::class);
+		$user1->method('getUID')
+			->willReturn('uid1');
+		$user1->method('getEMailAddress')
+			->willReturn('uid1@example.com');
+		$user2 = $this->createMock(IUser::class);
+		$user2->method('getUID')
+			->willReturn('uid2');
+		$user2->method('getEMailAddress')
+			->willReturn('uid2@example.com');
+		$user3 = $this->createMock(IUser::class);
+		$user3->method('getUID')
+			->willReturn('uid3');
+		$user3->method('getEMailAddress')
+			->willReturn('uid3@example.com');
+		$user4 = $this->createMock(IUser::class);
+		$user4->method('getUID')
+			->willReturn('uid4');
+		$user4->method('getEMailAddress')
+			->willReturn(null);
+
+		$users = [$user1, $user2, $user3, $user4];
+
+		$this->config->expects($this->at(0))
+			->method('getUserValue')
+			->with('uid1', 'core', 'lang', null)
+			->willReturn(null);
+		$this->config->expects($this->at(1))
+			->method('getUserValue')
+			->with('uid2', 'core', 'lang', null)
+			->willReturn('de');
+		$this->config->expects($this->at(2))
+			->method('getUserValue')
+			->with('uid3', 'core', 'lang', null)
+			->willReturn('de');
+
+		$enL10N = $this->createMock(IL10N::class);
+		$enL10N->method('t')
+			->will($this->returnArgument(0));
+		$enL10N->method('l')
+			->will($this->returnArgument(0));
+
+		$deL10N = $this->createMock(IL10N::class);
+		$deL10N->method('t')
+			->will($this->returnArgument(0));
+		$deL10N->method('l')
+			->will($this->returnArgument(0));
+
+		$this->l10nFactory->expects($this->at(0))
+			->method('findLanguage')
+			->with()
+			->willReturn('en');
+
+		$this->l10nFactory->expects($this->at(1))
+			->method('languageExists')
+			->with('dav', 'en')
+			->willReturn(true);
+
+		$this->l10nFactory->expects($this->at(2))
+			->method('get')
+			->with('dav', 'en')
+			->willReturn($enL10N);
+
+		$this->l10nFactory->expects($this->at(3))
+			->method('languageExists')
+			->with('dav', 'de')
+			->willReturn(true);
+
+		$this->l10nFactory->expects($this->at(4))
+			->method('get')
+			->with('dav', 'de')
+			->willReturn($deL10N);
+
+		$template1 = $this->getTemplateMock();
+		$message11 = $this->getMessageMock('uid1@example.com', $template1);
+		$template2 = $this->getTemplateMock();
+		$message21 = $this->getMessageMock('uid2@example.com', $template2);
+		$message22 = $this->getMessageMock('uid3@example.com', $template2);
+
+		$this->mailer->expects($this->at(0))
+			->method('createEMailTemplate')
+			->with('dav.calendarReminder')
+			->willReturn($template1);
+
+		$this->mailer->expects($this->at(1))
+			->method('createMessage')
+			->with()
+			->willReturn($message11);
+		$this->mailer->expects($this->at(2))
+			->method('send')
+			->with($message11)
+			->willReturn([]);
+
+		$this->mailer->expects($this->at(3))
+			->method('createEMailTemplate')
+			->with('dav.calendarReminder')
+			->willReturn($template2);
+
+		$this->mailer->expects($this->at(4))
+			->method('createMessage')
+			->with()
+			->willReturn($message21);
+		$this->mailer->expects($this->at(5))
+			->method('send')
+			->with($message21)
+			->willReturn([]);
+		$this->mailer->expects($this->at(6))
+			->method('createMessage')
+			->with()
+			->willReturn($message22);
+		$this->mailer->expects($this->at(7))
+			->method('send')
+			->with($message22)
+			->willReturn([]);
+
+		$this->setupURLGeneratorMock(2);
+
+		$vcalendar = $this->getNoAttendeeVCalendar();
+		$this->provider->send($vcalendar->VEVENT, $this->calendarDisplayName, $users);
+	}
+
+	public function testSendWithAttendees(): void {
+		$user1 = $this->createMock(IUser::class);
+		$user1->method('getUID')
+			->willReturn('uid1');
+		$user1->method('getEMailAddress')
+			->willReturn('uid1@example.com');
+		$user2 = $this->createMock(IUser::class);
+		$user2->method('getUID')
+			->willReturn('uid2');
+		$user2->method('getEMailAddress')
+			->willReturn('uid2@example.com');
+		$user3 = $this->createMock(IUser::class);
+		$user3->method('getUID')
+			->willReturn('uid3');
+		$user3->method('getEMailAddress')
+			->willReturn('uid3@example.com');
+		$user4 = $this->createMock(IUser::class);
+		$user4->method('getUID')
+			->willReturn('uid4');
+		$user4->method('getEMailAddress')
+			->willReturn(null);
+
+		$users = [$user1, $user2, $user3, $user4];
+
+		$this->config->expects($this->at(0))
+			->method('getUserValue')
+			->with('uid1', 'core', 'lang', null)
+			->willReturn(null);
+		$this->config->expects($this->at(1))
+			->method('getUserValue')
+			->with('uid2', 'core', 'lang', null)
+			->willReturn('de');
+		$this->config->expects($this->at(2))
+			->method('getUserValue')
+			->with('uid3', 'core', 'lang', null)
+			->willReturn('de');
+
+		$enL10N = $this->createMock(IL10N::class);
+		$enL10N->method('t')
+			->will($this->returnArgument(0));
+		$enL10N->method('l')
+			->will($this->returnArgument(0));
+
+		$deL10N = $this->createMock(IL10N::class);
+		$deL10N->method('t')
+			->will($this->returnArgument(0));
+		$deL10N->method('l')
+			->will($this->returnArgument(0));
+
+		$this->l10nFactory->expects($this->at(0))
+			->method('findLanguage')
+			->with()
+			->willReturn('en');
+
+		$this->l10nFactory->expects($this->at(1))
+			->method('languageExists')
+			->with('dav', 'de')
+			->willReturn(true);
+
+		$this->l10nFactory->expects($this->at(2))
+			->method('get')
+			->with('dav', 'de')
+			->willReturn($enL10N);
+
+		$this->l10nFactory->expects($this->at(3))
+			->method('languageExists')
+			->with('dav', 'en')
+			->willReturn(true);
+
+		$this->l10nFactory->expects($this->at(4))
+			->method('get')
+			->with('dav', 'en')
+			->willReturn($deL10N);
+
+		$template1 = $this->getTemplateMock();
+		$message11 = $this->getMessageMock('foo1@example.org', $template1);
+		$message12 = $this->getMessageMock('uid2@example.com', $template1);
+		$message13 = $this->getMessageMock('uid3@example.com', $template1);
+		$template2 = $this->getTemplateMock();
+		$message21 = $this->getMessageMock('foo3@example.org', $template2);
+		$message22 = $this->getMessageMock('foo4@example.org', $template2);
+		$message23 = $this->getMessageMock('uid1@example.com', $template2);
+
+		$this->mailer->expects($this->at(0))
+			->method('createEMailTemplate')
+			->with('dav.calendarReminder')
+			->willReturn($template1);
+
+		$this->mailer->expects($this->at(1))
+			->method('createMessage')
+			->with()
+			->willReturn($message11);
+		$this->mailer->expects($this->at(2))
+			->method('send')
+			->with($message11)
+			->willReturn([]);
+		$this->mailer->expects($this->at(3))
+			->method('createMessage')
+			->with()
+			->willReturn($message12);
+		$this->mailer->expects($this->at(4))
+			->method('send')
+			->with($message12)
+			->willReturn([]);
+		$this->mailer->expects($this->at(5))
+			->method('createMessage')
+			->with()
+			->willReturn($message13);
+		$this->mailer->expects($this->at(6))
+			->method('send')
+			->with($message13)
+			->willReturn([]);
+
+		$this->mailer->expects($this->at(7))
+			->method('createEMailTemplate')
+			->with('dav.calendarReminder')
+			->willReturn($template2);
+
+		$this->mailer->expects($this->at(8))
+			->method('createMessage')
+			->with()
+			->willReturn($message21);
+		$this->mailer->expects($this->at(9))
+			->method('send')
+			->with($message21)
+			->willReturn([]);
+		$this->mailer->expects($this->at(10))
+			->method('createMessage')
+			->with()
+			->willReturn($message22);
+		$this->mailer->expects($this->at(11))
+			->method('send')
+			->with($message22)
+			->willReturn([]);
+		$this->mailer->expects($this->at(12))
+			->method('createMessage')
+			->with()
+			->willReturn($message23);
+		$this->mailer->expects($this->at(13))
+			->method('send')
+			->with($message23)
+			->willReturn([]);
+
+		$this->setupURLGeneratorMock(2);
+
+		$vcalendar = $this->getAttendeeVCalendar();
+		$this->provider->send($vcalendar->VEVENT, $this->calendarDisplayName, $users);
+	}
+
+	/**
+	 * @return IEMailTemplate
+	 */
+	private function getTemplateMock():IEMailTemplate {
+		$template = $this->createMock(IEMailTemplate::class);
+
+		$template->expects($this->at(0))
+			->method('addHeader')
+			->with()
+			->willReturn($template);
+
+		$template->expects($this->at(1))
+			->method('setSubject')
+			->with()
+			->willReturn($template);
+
+		$template->expects($this->at(2))
+			->method('addHeading')
+			->with()
+			->willReturn($template);
+
+		$template->expects($this->at(3))
+			->method('addBodyListItem')
+			->with()
+			->willReturn($template);
+
+		$template->expects($this->at(4))
+			->method('addBodyListItem')
+			->with()
+			->willReturn($template);
+
+		$template->expects($this->at(5))
+			->method('addBodyListItem')
+			->with()
+			->willReturn($template);
+
+		$template->expects($this->at(6))
+			->method('addBodyListItem')
+			->with()
+			->willReturn($template);
+
+		$template->expects($this->at(7))
+			->method('addFooter')
+			->with()
+			->willReturn($template);
+
+		return $template;
+	}
+
+	/**
+	 * @param array $toMail
+	 * @param IEMailTemplate $templateMock
+	 * @param array $replyTo
+	 * @return IMessage
+	 */
+	private function getMessageMock(string $toMail, IEMailTemplate $templateMock, array $replyTo=null):IMessage {
+		$message = $this->createMock(IMessage::class);
+		$i = 0;
+
+		$message->expects($this->at($i++))
+			->method('setFrom')
+			->with([\OCP\Util::getDefaultEmailAddress('reminders-noreply')])
+			->willReturn($message);
+
+		if ($replyTo) {
+			$message->expects($this->at($i++))
+				->method('setReplyTo')
+				->with($replyTo)
+				->willReturn($message);
+		}
+
+		$message->expects($this->at($i++))
+			->method('setTo')
+			->with([$toMail])
+			->willReturn($message);
+
+		$message->expects($this->at($i++))
+			->method('useTemplate')
+			->with($templateMock)
+			->willReturn($message);
+
+		return $message;
+	}
+
+	private function getNoAttendeeVCalendar():VCalendar {
+		$vcalendar = new VCalendar();
+		$vcalendar->add('VEVENT', [
+			'SUMMARY' => 'Fellowship meeting',
+			'DTSTART' => new \DateTime('2017-01-01 00:00:00+00:00'), // 1483228800,
+			'UID' => 'uid1234',
+			'LOCATION' => 'Location 123',
+			'DESCRIPTION' => 'DESCRIPTION 456',
+		]);
+
+		return $vcalendar;
+	}
+
+	private function getAttendeeVCalendar():VCalendar {
+		$vcalendar = new VCalendar();
+		$vcalendar->add('VEVENT', [
+			'SUMMARY' => 'Fellowship meeting',
+			'DTSTART' => new \DateTime('2017-01-01 00:00:00+00:00'), // 1483228800,
+			'UID' => 'uid1234',
+			'LOCATION' => 'Location 123',
+			'DESCRIPTION' => 'DESCRIPTION 456',
+		]);
+
+		$vcalendar->VEVENT->add(
+			'ATTENDEE',
+			'mailto:foo1@example.org',
+			[
+				'LANG' => 'de',
+				'PARTSTAT' => 'NEEDS-ACTION',
+			]
+		);
+
+		$vcalendar->VEVENT->add(
+			'ATTENDEE',
+			'mailto:foo2@example.org',
+			[
+				'LANG' => 'de',
+				'PARTSTAT' => 'DECLINED',
+			]
+		);
+
+		$vcalendar->VEVENT->add(
+			'ATTENDEE',
+			'mailto:foo3@example.org',
+			[
+				'LANG' => 'en',
+				'PARTSTAT' => 'CONFIRMED',
+			]
+		);
+
+		$vcalendar->VEVENT->add(
+			'ATTENDEE',
+			'mailto:foo4@example.org'
+		);
+
+		$vcalendar->VEVENT->add(
+			'ATTENDEE',
+			'tomail:foo5@example.org'
+		);
+
+		return $vcalendar;
+	}
+
+	private function setupURLGeneratorMock(int $times=1):void {
+		for ($i = 0; $i < $times; $i++) {
+			$this->urlGenerator
+				->expects($this->at(8 * $i))
+				->method('imagePath')
+				->with('core', 'actions/info.svg')
+				->willReturn('imagePath1');
+
+			$this->urlGenerator
+				->expects($this->at(8 * $i + 1))
+				->method('getAbsoluteURL')
+				->with('imagePath1')
+				->willReturn('AbsURL1');
+
+			$this->urlGenerator
+				->expects($this->at(8 * $i + 2))
+				->method('imagePath')
+				->with('core', 'places/calendar.svg')
+				->willReturn('imagePath2');
+
+			$this->urlGenerator
+				->expects($this->at(8 * $i + 3))
+				->method('getAbsoluteURL')
+				->with('imagePath2')
+				->willReturn('AbsURL2');
+
+			$this->urlGenerator
+				->expects($this->at(8 * $i + 4))
+				->method('imagePath')
+				->with('core', 'actions/address.svg')
+				->willReturn('imagePath3');
+
+			$this->urlGenerator
+				->expects($this->at(8 * $i + 5))
+				->method('getAbsoluteURL')
+				->with('imagePath3')
+				->willReturn('AbsURL3');
+
+			$this->urlGenerator
+				->expects($this->at(8 * $i + 6))
+				->method('imagePath')
+				->with('core', 'actions/more.svg')
+				->willReturn('imagePath4');
+
+			$this->urlGenerator
+				->expects($this->at(8 * $i + 7))
+				->method('getAbsoluteURL')
+				->with('imagePath4')
+				->willReturn('AbsURL4');
+		}
+	}
+}
diff --git a/apps/dav/tests/unit/CalDAV/Reminder/NotificationProvider/PushProviderTest.php b/apps/dav/tests/unit/CalDAV/Reminder/NotificationProvider/PushProviderTest.php
new file mode 100644
index 00000000000..bbf71837b08
--- /dev/null
+++ b/apps/dav/tests/unit/CalDAV/Reminder/NotificationProvider/PushProviderTest.php
@@ -0,0 +1,186 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+namespace OCA\DAV\Tests\unit\CalDAV\Reminder\NotificationProvider;
+
+use OCA\DAV\AppInfo\Application;
+use OCA\DAV\CalDAV\Reminder\NotificationProvider\PushProvider;
+use OCP\IConfig;
+use OCP\IL10N;
+use OCP\ILogger;
+use OCP\IURLGenerator;
+use OCP\L10N\IFactory as L10NFactory;
+use OCP\IUser;
+use OCP\Notification\IManager;
+use OCP\Notification\INotification;
+use OCP\AppFramework\Utility\ITimeFactory;
+use Test\TestCase;
+
+class PushProviderTest extends AbstractNotificationProviderTest {
+
+    /** @var ILogger|\PHPUnit\Framework\MockObject\MockObject */
+    protected $logger;
+
+    /** @var L10NFactory|\PHPUnit\Framework\MockObject\MockObject */
+    protected $l10nFactory;
+
+    /** @var IL10N|\PHPUnit\Framework\MockObject\MockObject */
+    protected $l10n;
+
+    /** @var IURLGenerator|\PHPUnit\Framework\MockObject\MockObject */
+    protected $urlGenerator;
+
+    /** @var IConfig|\PHPUnit\Framework\MockObject\MockObject */
+    protected $config;
+
+    /** @var IManager|\PHPUnit\Framework\MockObject\MockObject */
+    private $manager;
+
+    /** @var ITimeFactory|\PHPUnit\Framework\MockObject\MockObject */
+    private $timeFactory;
+
+    public function setUp() {
+        parent::setUp();
+
+        $this->manager = $this->createMock(IManager::class);
+        $this->timeFactory = $this->createMock(ITimeFactory::class);
+
+        $this->provider = new PushProvider(
+            $this->config,
+            $this->manager,
+            $this->logger,
+            $this->l10nFactory,
+            $this->urlGenerator,
+            $this->timeFactory
+        );
+    }
+
+    public function testNotificationType():void  {
+    	$this->assertEquals(PushProvider::NOTIFICATION_TYPE, 'DISPLAY');
+	}
+
+    public function testSend(): void {
+    	$user1 = $this->createMock(IUser::class);
+    	$user1->method('getUID')
+			->willReturn('uid1');
+    	$user2 = $this->createMock(IUser::class);
+		$user2->method('getUID')
+			->willReturn('uid2');
+    	$user3 = $this->createMock(IUser::class);
+		$user3->method('getUID')
+			->willReturn('uid3');
+
+		$users = [$user1, $user2, $user3];
+
+		$dateTime = new \DateTime('@946684800');
+		$this->timeFactory->method('getDateTime')
+			->with()
+			->willReturn($dateTime);
+
+		$notification1 = $this->createNotificationMock('uid1', $dateTime);
+		$notification2 = $this->createNotificationMock('uid2', $dateTime);
+		$notification3 = $this->createNotificationMock('uid3', $dateTime);
+
+		$this->manager->expects($this->at(0))
+			->method('createNotification')
+			->with()
+			->willReturn($notification1);
+		$this->manager->expects($this->at(2))
+			->method('createNotification')
+			->with()
+			->willReturn($notification2);
+		$this->manager->expects($this->at(4))
+			->method('createNotification')
+			->with()
+			->willReturn($notification3);
+
+		$this->manager->expects($this->at(1))
+			->method('notify')
+			->with($notification1);
+		$this->manager->expects($this->at(3))
+			->method('notify')
+			->with($notification2);
+		$this->manager->expects($this->at(5))
+			->method('notify')
+			->with($notification3);
+
+		$this->provider->send($this->vcalendar->VEVENT, $this->calendarDisplayName, $users);
+    }
+
+	/**
+	 * @param string $uid
+	 * @param \DateTime $dt
+	 */
+    private function createNotificationMock(string $uid, \DateTime $dt):INotification {
+		$notification = $this->createMock(INotification::class);
+		$notification
+			->expects($this->once())
+			->method('setApp')
+			->with('dav')
+			->willReturn($notification);
+
+		$notification->expects($this->once())
+			->method('setUser')
+			->with($uid)
+			->willReturn($notification);
+
+		$notification->expects($this->once())
+			->method('setDateTime')
+			->with($dt)
+			->willReturn($notification);
+
+		$notification->expects($this->once())
+			->method('setObject')
+			->with('dav', 'uid1234')
+			->willReturn($notification);
+
+		$notification->expects($this->once())
+			->method('setSubject')
+			->with('calendar_reminder', [
+				'title' => 'Fellowship meeting',
+				'start_atom' => '2017-01-01T00:00:00+00:00',
+			])
+			->willReturn($notification);
+
+		$notification
+			->expects($this->once())
+			->method('setMessage')
+			->with('calendar_reminder', [
+				'title' => 'Fellowship meeting',
+				'start_atom' => '2017-01-01T00:00:00+00:00',
+				'description' => null,
+				'location' => null,
+				'all_day' => false,
+				'start_is_floating' => false,
+				'start_timezone' => 'UTC',
+				'end_atom' => '2017-01-01T00:00:00+00:00',
+				'end_is_floating' => false,
+				'end_timezone' => 'UTC',
+				'calendar_displayname' => 'Personal',
+			])
+			->willReturn($notification);
+
+		return $notification;
+	}
+}
diff --git a/apps/dav/tests/unit/CalDAV/Reminder/NotificationProviderManagerTest.php b/apps/dav/tests/unit/CalDAV/Reminder/NotificationProviderManagerTest.php
new file mode 100644
index 00000000000..b4c62eacd7a
--- /dev/null
+++ b/apps/dav/tests/unit/CalDAV/Reminder/NotificationProviderManagerTest.php
@@ -0,0 +1,94 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+namespace OCA\DAV\Tests\unit\CalDAV\Reminder;
+
+use OCA\DAV\CalDAV\Reminder\NotificationProvider\EmailProvider;
+use OCA\DAV\CalDAV\Reminder\NotificationProvider\ProviderNotAvailableException;
+use OCA\DAV\CalDAV\Reminder\NotificationProvider\PushProvider;
+use OCA\DAV\CalDAV\Reminder\NotificationProviderManager;
+use OCA\DAV\CalDAV\Reminder\NotificationTypeDoesNotExistException;
+use OCA\DAV\Capabilities;
+use Test\TestCase;
+
+class NotificationProviderManagerTest extends TestCase {
+
+	/** @var NotificationProviderManager|\PHPUnit\Framework\MockObject\MockObject */
+	private $providerManager;
+
+	/**
+	 * @throws \OCP\AppFramework\QueryException
+	 */
+	public function setUp() {
+		parent::setUp();
+
+		$this->providerManager = new NotificationProviderManager();
+		$this->providerManager->registerProvider(EmailProvider::class);
+	}
+
+	/**
+	 * @expectedException OCA\DAV\CalDAV\Reminder\NotificationTypeDoesNotExistException
+	 * @expectedExceptionMessage Type NOT EXISTENT is not an accepted type of notification
+	 * @throws ProviderNotAvailableException
+	 * @throws NotificationTypeDoesNotExistException
+	 */
+	public function testGetProviderForUnknownType(): void{
+		$this->providerManager->getProvider('NOT EXISTENT');
+	}
+
+	/**
+	 * @expectedException OCA\DAV\CalDAV\Reminder\NotificationProvider\ProviderNotAvailableException
+	 * @expectedExceptionMessage No notification provider for type AUDIO available
+	 * @throws NotificationTypeDoesNotExistException
+	 * @throws ProviderNotAvailableException
+	 */
+	public function testGetProviderForUnRegisteredType(): void{
+		$this->providerManager->getProvider('AUDIO');
+	}
+
+	public function testGetProvider(): void{
+		$provider = $this->providerManager->getProvider('EMAIL');
+		$this->assertInstanceOf(EmailProvider::class, $provider);
+	}
+
+	public function testRegisterProvider(): void{
+		$this->providerManager->registerProvider(PushProvider::class);
+		$provider = $this->providerManager->getProvider('DISPLAY');
+		$this->assertInstanceOf(PushProvider::class, $provider);
+	}
+
+	/**
+	 * @expectedExceptionMessage Invalid notification provider registered
+	 * @expectedException \InvalidArgumentException
+	 * @throws \OCP\AppFramework\QueryException
+	 */
+	public function testRegisterBadProvider(): void{
+		$this->providerManager->registerProvider(Capabilities::class);
+	}
+
+	public function testHasProvider(): void {
+		$this->assertTrue($this->providerManager->hasProvider('EMAIL'));
+		$this->assertFalse($this->providerManager->hasProvider('EMAIL123'));
+	}
+}
diff --git a/apps/dav/tests/unit/CalDAV/Reminder/NotifierTest.php b/apps/dav/tests/unit/CalDAV/Reminder/NotifierTest.php
new file mode 100644
index 00000000000..8d38617ad2a
--- /dev/null
+++ b/apps/dav/tests/unit/CalDAV/Reminder/NotifierTest.php
@@ -0,0 +1,220 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ * @copyright Copyright (c) 2019, Georg Ehrke
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCA\DAV\Tests\unit\CalDAV\Reminder;
+
+use OCA\DAV\AppInfo\Application;
+use OCA\DAV\CalDAV\Reminder\Notifier;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\IL10N;
+use OCP\IURLGenerator;
+use OCP\L10N\IFactory;
+use OCP\Notification\INotification;
+use Test\TestCase;
+
+class NotifierTest extends TestCase {
+	/** @var Notifier */
+	protected $notifier;
+
+	/** @var IFactory|\PHPUnit\Framework\MockObject\MockObject */
+	protected $factory;
+
+	/** @var IURLGenerator|\PHPUnit\Framework\MockObject\MockObject */
+	protected $urlGenerator;
+
+	/** @var IL10N|\PHPUnit\Framework\MockObject\MockObject */
+	protected $l10n;
+
+	/** @var ITimeFactory|\PHPUnit\Framework\MockObject\MockObject */
+	protected $timeFactory;
+
+	protected function setUp() {
+		parent::setUp();
+
+		$this->urlGenerator = $this->createMock(IURLGenerator::class);
+		$this->l10n = $this->createMock(IL10N::class);
+		$this->l10n->expects($this->any())
+			->method('t')
+			->willReturnCallback(function($string, $args) {
+				return vsprintf($string, $args);
+			});
+		$this->l10n->expects($this->any())
+			->method('l')
+			->willReturnCallback(function($string, $args) {
+				/** \DateTime $args */
+				return $args->format(\DateTime::ATOM);
+			});
+		$this->l10n->expects($this->any())
+			->method('n')
+			->willReturnCallback(function($textSingular, $textPlural, $count, $args) {
+				$text = $count === 1 ? $textSingular : $textPlural;
+				$text = str_replace('%n', (string)$count, $text);
+				return vsprintf($text, $args);
+			});
+		$this->factory = $this->createMock(IFactory::class);
+		$this->factory->expects($this->any())
+			->method('get')
+			->willReturn($this->l10n);
+
+		$this->timeFactory = $this->createMock(ITimeFactory::class);
+		$this->timeFactory
+			->method('getDateTime')
+			->willReturn(\DateTime::createFromFormat(\DateTime::ATOM, '2005-08-15T14:00:00+02:00'));
+
+		$this->notifier = new Notifier(
+			$this->factory,
+			$this->urlGenerator,
+			$this->timeFactory
+		);
+	}
+
+	public function testGetId():void {
+		$this->assertEquals($this->notifier->getID(), 'dav');
+	}
+
+	public function testGetName():void {
+		$this->assertEquals($this->notifier->getName(), 'Calendar');
+	}
+
+	/**
+	 * @expectedException \InvalidArgumentException
+	 * @expectedExceptionMessage Notification not from this app
+	 */
+	public function testPrepareWrongApp(): void
+	{
+		/** @var INotification|\PHPUnit\Framework\MockObject\MockObject $notification */
+		$notification = $this->createMock(INotification::class);
+
+		$notification->expects($this->once())
+			->method('getApp')
+			->willReturn('notifications');
+		$notification->expects($this->never())
+			->method('getSubject');
+
+		$this->notifier->prepare($notification, 'en');
+	}
+
+	/**
+	 * @expectedException \InvalidArgumentException
+	 * @expectedExceptionMessage Unknown subject
+	 */
+	public function testPrepareWrongSubject() {
+		/** @var INotification|\PHPUnit\Framework\MockObject\MockObject $notification */
+		$notification = $this->createMock(INotification::class);
+
+		$notification->expects($this->once())
+			->method('getApp')
+			->willReturn(Application::APP_ID);
+		$notification->expects($this->once())
+			->method('getSubject')
+			->willReturn('wrong subject');
+
+		$this->notifier->prepare($notification, 'en');
+	}
+
+	public function dataPrepare(): array
+	{
+		return [
+			[
+				'calendar_reminder',
+				[
+					'title' => 'Title of this event',
+					'start_atom' => '2005-08-15T15:52:01+02:00'
+				],
+				'Title of this event (in 1 hour, 52 minutes)',
+				[
+					'title' => 'Title of this event',
+					'description' => null,
+					'location' => 'NC Headquarters',
+					'all_day' => false,
+					'start_atom' => '2005-08-15T15:52:01+02:00',
+					'start_is_floating' => false,
+					'start_timezone' => 'Europe/Berlin',
+					'end_atom' => '2005-08-15T17:52:01+02:00',
+					'end_is_floating' => false,
+					'end_timezone' => 'Europe/Berlin',
+					'calendar_displayname' => 'Personal',
+				],
+				"Calendar: Personal\r\nDate: 2005-08-15T15:52:01+02:00, 2005-08-15T15:52:01+02:00 - 2005-08-15T17:52:01+02:00 (Europe/Berlin)\r\nWhere: NC Headquarters"
+			],
+		];
+	}
+
+	/**
+	 * @dataProvider dataPrepare
+	 *
+	 * @param string $subjectType
+	 * @param array $subjectParams
+	 * @param string $subject
+	 * @param array $messageParams
+	 * @param string $message
+	 * @throws \Exception
+	 */
+	public function testPrepare(string $subjectType, array $subjectParams, string $subject, array $messageParams, string $message): void
+	{
+		/** @var INotification|\PHPUnit\Framework\MockObject\MockObject $notification */
+		$notification = $this->createMock(INotification::class);
+
+		$notification->expects($this->once())
+			->method('getApp')
+			->willReturn(Application::APP_ID);
+		$notification->expects($this->once())
+			->method('getSubject')
+			->willReturn($subjectType);
+		$notification->expects($this->once())
+			->method('getSubjectParameters')
+			->willReturn($subjectParams);
+		$notification->expects($this->once())
+			->method('getMessageParameters')
+			->willReturn($messageParams);
+
+		$notification->expects($this->once())
+			->method('setParsedSubject')
+			->with($subject)
+			->willReturnSelf();
+
+		$notification->expects($this->once())
+			->method('setParsedMessage')
+			->with($message)
+			->willReturnSelf();
+
+		$this->urlGenerator->expects($this->once())
+			->method('imagePath')
+			->with('core', 'places/calendar.svg')
+			->willReturn('icon-url');
+		$this->urlGenerator->expects($this->once())
+			->method('getAbsoluteURL')
+			->with('icon-url')
+			->willReturn('absolute-icon-url');
+		$notification->expects($this->once())
+			->method('setIcon')
+			->with('absolute-icon-url')
+			->willReturnSelf();
+
+		$return = $this->notifier->prepare($notification, 'en');
+
+		$this->assertEquals($notification, $return);
+	}
+}
diff --git a/apps/dav/tests/unit/CalDAV/Reminder/ReminderServiceTest.php b/apps/dav/tests/unit/CalDAV/Reminder/ReminderServiceTest.php
new file mode 100644
index 00000000000..a9acca66a81
--- /dev/null
+++ b/apps/dav/tests/unit/CalDAV/Reminder/ReminderServiceTest.php
@@ -0,0 +1,555 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Thomas Citharel
+ *
+ * @author Thomas Citharel <tcit@tcit.fr>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+namespace OCA\DAV\Tests\unit\CalDAV\Reminder;
+
+use OCA\DAV\CalDAV\CalDavBackend;
+use OCA\DAV\CalDAV\Reminder\AbstractNotificationProvider;
+use OCA\DAV\CalDAV\Reminder\Backend;
+use OCA\DAV\CalDAV\Reminder\INotificationProvider;
+use OCA\DAV\CalDAV\Reminder\NotificationProviderManager;
+use OCA\DAV\CalDAV\Reminder\NotificationProvider\EmailProvider;
+use OCA\DAV\CalDAV\Reminder\NotificationProvider\PushProvider;
+use OCA\DAV\CalDAV\Reminder\ReminderService;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\IGroup;
+use OCP\IGroupManager;
+use OCP\IUser;
+use OCP\IUserManager;
+use OCP\IUserSession;
+use Test\TestCase;
+
+class ReminderServiceTest extends TestCase {
+
+    /** @var Backend|\PHPUnit\Framework\MockObject\MockObject */
+    private $backend;
+
+    /** @var NotificationProviderManager|\PHPUnit\Framework\MockObject\MockObject */
+    private $notificationProviderManager;
+
+	/** @var IUserManager|\PHPUnit\Framework\MockObject\MockObject */
+	private $userManager;
+
+	/** @var IGroupManager|\PHPUnit\Framework\MockObject\MockObject*/
+	private $groupManager;
+
+	/** @var IUserSession|\PHPUnit\Framework\MockObject\MockObject */
+	private $userSession;
+
+	/** @var CalDavBackend|\PHPUnit\Framework\MockObject\MockObject */
+	private $caldavBackend;
+
+	/** @var ITimeFactory|\PHPUnit\Framework\MockObject\MockObject  */
+	private $timeFactory;
+
+	/** @var ReminderService */
+	private $reminderService;
+
+	public const CALENDAR_DATA = <<<EOD
+BEGIN:VCALENDAR
+PRODID:-//Nextcloud calendar v1.6.4
+BEGIN:VEVENT
+CREATED:20160602T133732
+DTSTAMP:20160602T133732
+LAST-MODIFIED:20160602T133732
+UID:wej2z68l9h
+SUMMARY:Test Event
+LOCATION:Somewhere ...
+DESCRIPTION:maybe ....
+DTSTART;TZID=Europe/Berlin;VALUE=DATE:20160609
+DTEND;TZID=Europe/Berlin;VALUE=DATE:20160610
+BEGIN:VALARM
+ACTION:EMAIL
+TRIGGER:-PT15M
+END:VALARM
+BEGIN:VALARM
+ACTION:DISPLAY
+TRIGGER;VALUE=DATE-TIME:20160608T000000Z
+END:VALARM
+END:VEVENT
+END:VCALENDAR
+EOD;
+
+	public const CALENDAR_DATA_REPEAT = <<<EOD
+BEGIN:VCALENDAR
+PRODID:-//Nextcloud calendar v1.6.4
+BEGIN:VEVENT
+CREATED:20160602T133732
+DTSTAMP:20160602T133732
+LAST-MODIFIED:20160602T133732
+UID:wej2z68l9h
+SUMMARY:Test Event
+LOCATION:Somewhere ...
+DESCRIPTION:maybe ....
+DTSTART;TZID=Europe/Berlin;VALUE=DATE:20160609
+DTEND;TZID=Europe/Berlin;VALUE=DATE:20160610
+BEGIN:VALARM
+ACTION:EMAIL
+TRIGGER:-PT15M
+REPEAT:4
+DURATION:PT2M
+END:VALARM
+END:VEVENT
+END:VCALENDAR
+EOD;
+
+	public const CALENDAR_DATA_RECURRING = <<<EOD
+BEGIN:VCALENDAR
+PRODID:-//Nextcloud calendar v1.6.4
+BEGIN:VEVENT
+CREATED:20160602T133732
+DTSTAMP:20160602T133732
+LAST-MODIFIED:20160602T133732
+UID:wej2z68l9h
+SUMMARY:Test Event
+LOCATION:Somewhere ...
+DESCRIPTION:maybe ....
+DTSTART;TZID=Europe/Berlin;VALUE=DATE:20160609
+DTEND;TZID=Europe/Berlin;VALUE=DATE:20160610
+RRULE:FREQ=WEEKLY
+BEGIN:VALARM
+ACTION:EMAIL
+TRIGGER:-PT15M
+END:VALARM
+BEGIN:VALARM
+ACTION:EMAIL
+TRIGGER:-P8D
+END:VALARM
+END:VEVENT
+END:VCALENDAR
+EOD;
+
+	public const CALENDAR_DATA_RECURRING_REPEAT = <<<EOD
+BEGIN:VCALENDAR
+PRODID:-//Nextcloud calendar v1.6.4
+BEGIN:VEVENT
+CREATED:20160602T133732
+DTSTAMP:20160602T133732
+LAST-MODIFIED:20160602T133732
+UID:wej2z68l9h
+SUMMARY:Test Event
+LOCATION:Somewhere ...
+DESCRIPTION:maybe ....
+DTSTART;TZID=Europe/Berlin;VALUE=DATE:20160609
+DTEND;TZID=Europe/Berlin;VALUE=DATE:20160610
+RRULE:FREQ=WEEKLY
+BEGIN:VALARM
+ACTION:EMAIL
+TRIGGER:-PT15M
+REPEAT:4
+DURATION:PT2M
+END:VALARM
+BEGIN:VALARM
+ACTION:EMAIL
+TRIGGER:-P8D
+END:VALARM
+END:VEVENT
+END:VCALENDAR
+EOD;
+
+    public function setUp() {
+		parent::setUp();
+
+        $this->backend = $this->createMock(Backend::class);
+        $this->notificationProviderManager = $this->createMock(NotificationProviderManager::class);
+        $this->userManager = $this->createMock(IUserManager::class);
+		$this->groupManager = $this->createMock(IGroupManager::class);
+		$this->caldavBackend = $this->createMock(CalDavBackend::class);
+		$this->timeFactory = $this->createMock(ITimeFactory::class);
+
+		$this->caldavBackend->method('getShares')->willReturn([]);
+
+		$this->reminderService = new ReminderService($this->backend,
+			$this->notificationProviderManager,
+			$this->userManager,
+			$this->groupManager,
+			$this->caldavBackend,
+			$this->timeFactory);
+    }
+
+	public function testOnCalendarObjectDelete():void {
+    	$this->backend->expects($this->once())
+			->method('cleanRemindersForEvent')
+			->with(44);
+
+    	$action = '\OCA\DAV\CalDAV\CalDavBackend::deleteCalendarObject';
+		$objectData = [
+			'id' => '44',
+			'component' => 'vevent',
+		];
+
+		$this->reminderService->onTouchCalendarObject($action, $objectData);
+	}
+
+	public function testOnCalendarObjectCreateSingleEntry():void {
+		$action = '\OCA\DAV\CalDAV\CalDavBackend::createCalendarObject';
+    	$objectData = [
+    		'calendardata' => self::CALENDAR_DATA,
+			'id' => '42',
+			'calendarid' => '1337',
+			'component' => 'vevent',
+		];
+
+    	$this->backend->expects($this->exactly(2))
+			->method('insertReminder')
+			->withConsecutive(
+				[1337, 42, 'wej2z68l9h', false, 1465430400, false, '5c70531aab15c92b52518ae10a2f78a4', 'de919af7429d3b5c11e8b9d289b411a6', 'EMAIL', true, 1465429500, false],
+				[1337, 42, 'wej2z68l9h', false, 1465430400, false, '5c70531aab15c92b52518ae10a2f78a4', '35b3eae8e792aa2209f0b4e1a302f105', 'DISPLAY', false, 1465344000, false]
+			)
+			->willReturn(1);
+
+    	$this->timeFactory->expects($this->once())
+			->method('getDateTime')
+			->with()
+			->willReturn(\DateTime::createFromFormat(\DateTime::ATOM, '2016-06-08T00:00:00+00:00'));
+
+    	$this->reminderService->onTouchCalendarObject($action, $objectData);
+	}
+
+	public function testOnCalendarObjectCreateSingleEntryWithRepeat(): void {
+		$action = '\OCA\DAV\CalDAV\CalDavBackend::createCalendarObject';
+		$objectData = [
+			'calendardata' => self::CALENDAR_DATA_REPEAT,
+			'id' => '42',
+			'calendarid' => '1337',
+			'component' => 'vevent',
+		];
+
+		$this->backend->expects($this->exactly(5))
+			->method('insertReminder')
+			->withConsecutive(
+				[1337, 42, 'wej2z68l9h', false, 1465430400, false, '5c70531aab15c92b52518ae10a2f78a4', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1465429500, false],
+				[1337, 42, 'wej2z68l9h', false, 1465430400, false, '5c70531aab15c92b52518ae10a2f78a4', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1465429620, true],
+				[1337, 42, 'wej2z68l9h', false, 1465430400, false, '5c70531aab15c92b52518ae10a2f78a4', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1465429740, true],
+				[1337, 42, 'wej2z68l9h', false, 1465430400, false, '5c70531aab15c92b52518ae10a2f78a4', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1465429860, true],
+				[1337, 42, 'wej2z68l9h', false, 1465430400, false, '5c70531aab15c92b52518ae10a2f78a4', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1465429980, true]
+			)
+			->willReturn(1);
+
+		$this->timeFactory->expects($this->once())
+			->method('getDateTime')
+			->with()
+			->willReturn(\DateTime::createFromFormat(\DateTime::ATOM, '2016-06-08T00:00:00+00:00'));
+
+		$this->reminderService->onTouchCalendarObject($action, $objectData);
+	}
+
+	public function testOnCalendarObjectCreateRecurringEntry(): void {
+		$action = '\OCA\DAV\CalDAV\CalDavBackend::createCalendarObject';
+		$objectData = [
+			'calendardata' => self::CALENDAR_DATA_RECURRING,
+			'id' => '42',
+			'calendarid' => '1337',
+			'component' => 'vevent',
+		];
+
+		$this->backend->expects($this->exactly(2))
+			->method('insertReminder')
+			->withConsecutive(
+				[1337, 42, 'wej2z68l9h', true, 1467244800, false, 'fbdb2726bc0f7dfacac1d881c1453e20', 'de919af7429d3b5c11e8b9d289b411a6', 'EMAIL', true, 1467243900, false],
+				[1337, 42, 'wej2z68l9h', true, 1467849600, false, 'fbdb2726bc0f7dfacac1d881c1453e20', '8996992118817f9f311ac5cc56d1cc97', 'EMAIL', true, 1467158400, false]
+			)
+			->willReturn(1);
+
+		$this->timeFactory->expects($this->once())
+			->method('getDateTime')
+			->with()
+			->willReturn(\DateTime::createFromFormat(\DateTime::ATOM, '2016-06-29T00:00:00+00:00'));
+
+		$this->reminderService->onTouchCalendarObject($action, $objectData);
+	}
+
+	public function testOnCalendarObjectCreateRecurringEntryWithRepeat():void {
+		$action = '\OCA\DAV\CalDAV\CalDavBackend::createCalendarObject';
+		$objectData = [
+			'calendardata' => self::CALENDAR_DATA_RECURRING_REPEAT,
+			'id' => '42',
+			'calendarid' => '1337',
+			'component' => 'vevent',
+		];
+
+		$this->backend->expects($this->exactly(6))
+			->method('insertReminder')
+			->withConsecutive(
+				[1337, 42, 'wej2z68l9h', true, 1467244800, false, 'fbdb2726bc0f7dfacac1d881c1453e20', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1467243900, false],
+				[1337, 42, 'wej2z68l9h', true, 1467244800, false, 'fbdb2726bc0f7dfacac1d881c1453e20', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1467244020, true],
+				[1337, 42, 'wej2z68l9h', true, 1467244800, false, 'fbdb2726bc0f7dfacac1d881c1453e20', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1467244140, true],
+				[1337, 42, 'wej2z68l9h', true, 1467244800, false, 'fbdb2726bc0f7dfacac1d881c1453e20', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1467244260, true],
+				[1337, 42, 'wej2z68l9h', true, 1467244800, false, 'fbdb2726bc0f7dfacac1d881c1453e20', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1467244380, true],
+				[1337, 42, 'wej2z68l9h', true, 1467849600, false, 'fbdb2726bc0f7dfacac1d881c1453e20', '8996992118817f9f311ac5cc56d1cc97', 'EMAIL', true, 1467158400, false]
+			)
+			->willReturn(1);
+
+		$this->timeFactory->expects($this->once())
+			->method('getDateTime')
+			->with()
+			->willReturn(\DateTime::createFromFormat(\DateTime::ATOM, '2016-06-29T00:00:00+00:00'));
+
+		$this->reminderService->onTouchCalendarObject($action, $objectData);
+	}
+
+	public function testProcessReminders():void {
+		$this->backend->expects($this->at(0))
+			->method('getRemindersToProcess')
+			->with()
+			->willReturn([
+				[
+					'id' => 1,
+					'calendar_id' => 1337,
+					'object_id' => 42,
+					'uid' => 'wej2z68l9h',
+					'is_recurring' => false,
+					'recurrence_id' => 1465430400,
+					'is_recurrence_exception' => false,
+					'event_hash' => '5c70531aab15c92b52518ae10a2f78a4',
+					'alarm_hash' => 'de919af7429d3b5c11e8b9d289b411a6',
+					'type' => 'EMAIL',
+					'is_relative' => true,
+					'notification_date' => 1465429500,
+					'is_repeat_based' => false,
+					'calendardata' => self::CALENDAR_DATA,
+					'displayname' => 'Displayname 123',
+					'principaluri' => 'principals/users/user001',
+				],
+				[
+					'id' => 2,
+					'calendar_id' => 1337,
+					'object_id' => 42,
+					'uid' => 'wej2z68l9h',
+					'is_recurring' => false,
+					'recurrence_id' => 1465430400,
+					'is_recurrence_exception' => false,
+					'event_hash' => '5c70531aab15c92b52518ae10a2f78a4',
+					'alarm_hash' => 'ecacbf07d413c3c78d1ac7ad8c469602',
+					'type' => 'EMAIL',
+					'is_relative' => true,
+					'notification_date' => 1465429740,
+					'is_repeat_based' => true,
+					'calendardata' => self::CALENDAR_DATA_REPEAT,
+					'displayname' => 'Displayname 123',
+					'principaluri' => 'principals/users/user001',
+				],
+				[
+					'id' => 3,
+					'calendar_id' => 1337,
+					'object_id' => 42,
+					'uid' => 'wej2z68l9h',
+					'is_recurring' => false,
+					'recurrence_id' => 1465430400,
+					'is_recurrence_exception' => false,
+					'event_hash' => '5c70531aab15c92b52518ae10a2f78a4',
+					'alarm_hash' => '35b3eae8e792aa2209f0b4e1a302f105',
+					'type' => 'DISPLAY',
+					'is_relative' => false,
+					'notification_date' => 1465344000,
+					'is_repeat_based' => false,
+					'calendardata' =>  self::CALENDAR_DATA,
+					'displayname' => 'Displayname 123',
+					'principaluri' => 'principals/users/user001',
+				],
+				[
+					'id' => 4,
+					'calendar_id' => 1337,
+					'object_id' => 42,
+					'uid' => 'wej2z68l9h',
+					'is_recurring' => true,
+					'recurrence_id' => 1467244800,
+					'is_recurrence_exception' => false,
+					'event_hash' => 'fbdb2726bc0f7dfacac1d881c1453e20',
+					'alarm_hash' => 'ecacbf07d413c3c78d1ac7ad8c469602',
+					'type' => 'EMAIL',
+					'is_relative' => true,
+					'notification_date' => 1467243900,
+					'is_repeat_based' => false,
+					'calendardata' => self::CALENDAR_DATA_RECURRING_REPEAT,
+					'displayname' => 'Displayname 123',
+					'principaluri' => 'principals/users/user001',
+				],
+				[
+					'id' => 5,
+					'calendar_id' => 1337,
+					'object_id' => 42,
+					'uid' => 'wej2z68l9h',
+					'is_recurring' => true,
+					'recurrence_id' => 1467849600,
+					'is_recurrence_exception' => false,
+					'event_hash' => 'fbdb2726bc0f7dfacac1d881c1453e20',
+					'alarm_hash' => '8996992118817f9f311ac5cc56d1cc97',
+					'type' => 'EMAIL',
+					'is_relative' => true,
+					'notification_date' => 1467158400,
+					'is_repeat_based' => false,
+					'calendardata' => self::CALENDAR_DATA_RECURRING,
+					'displayname' => 'Displayname 123',
+					'principaluri' => 'principals/users/user001',
+				]
+			]);
+
+		$this->notificationProviderManager->expects($this->at(0))
+			->method('hasProvider')
+			->with('EMAIL')
+			->willReturn(true);
+
+		$provider1 = $this->createMock(INotificationProvider::class);
+		$this->notificationProviderManager->expects($this->at(1))
+			->method('getProvider')
+			->with('EMAIL')
+			->willReturn($provider1);
+
+		$this->notificationProviderManager->expects($this->at(2))
+			->method('hasProvider')
+			->with('EMAIL')
+			->willReturn(true);
+
+		$provider2 = $this->createMock(INotificationProvider::class);
+		$this->notificationProviderManager->expects($this->at(3))
+			->method('getProvider')
+			->with('EMAIL')
+			->willReturn($provider2);
+
+		$this->notificationProviderManager->expects($this->at(4))
+			->method('hasProvider')
+			->with('DISPLAY')
+			->willReturn(true);
+
+		$provider3 = $this->createMock(INotificationProvider::class);
+		$this->notificationProviderManager->expects($this->at(5))
+			->method('getProvider')
+			->with('DISPLAY')
+			->willReturn($provider3);
+
+		$this->notificationProviderManager->expects($this->at(6))
+			->method('hasProvider')
+			->with('EMAIL')
+			->willReturn(true);
+
+		$provider4 = $this->createMock(INotificationProvider::class);
+		$this->notificationProviderManager->expects($this->at(7))
+			->method('getProvider')
+			->with('EMAIL')
+			->willReturn($provider4);
+
+		$this->notificationProviderManager->expects($this->at(8))
+			->method('hasProvider')
+			->with('EMAIL')
+			->willReturn(true);
+
+		$provider5 = $this->createMock(INotificationProvider::class);
+		$this->notificationProviderManager->expects($this->at(9))
+			->method('getProvider')
+			->with('EMAIL')
+			->willReturn($provider5);
+
+		$user = $this->createMock(IUser::class);
+		$this->userManager->expects($this->exactly(5))
+			->method('get')
+			->with('user001')
+			->willReturn($user);
+
+		$provider1->expects($this->once())
+			->method('send')
+			->with($this->callback(function($vevent) {
+				if ($vevent->DTSTART->getDateTime()->format(\DateTime::ATOM) !== '2016-06-09T00:00:00+00:00') {
+					return false;
+				}
+				return true;
+			}, 'Displayname 123', $user));
+		$provider2->expects($this->once())
+			->method('send')
+			->with($this->callback(function($vevent) {
+				if ($vevent->DTSTART->getDateTime()->format(\DateTime::ATOM) !== '2016-06-09T00:00:00+00:00') {
+					return false;
+				}
+				return true;
+			}, 'Displayname 123', $user));
+		$provider3->expects($this->once())
+			->method('send')
+			->with($this->callback(function($vevent) {
+				if ($vevent->DTSTART->getDateTime()->format(\DateTime::ATOM) !== '2016-06-09T00:00:00+00:00') {
+					return false;
+				}
+				return true;
+			}, 'Displayname 123', $user));
+		$provider4->expects($this->once())
+			->method('send')
+			->with($this->callback(function($vevent) {
+				if ($vevent->DTSTART->getDateTime()->format(\DateTime::ATOM) !== '2016-06-30T00:00:00+00:00') {
+					return false;
+				}
+				return true;
+			}, 'Displayname 123', $user));
+		$provider5->expects($this->once())
+			->method('send')
+			->with($this->callback(function($vevent) {
+				if ($vevent->DTSTART->getDateTime()->format(\DateTime::ATOM) !== '2016-07-07T00:00:00+00:00') {
+					return false;
+				}
+				return true;
+			}, 'Displayname 123', $user));
+
+		$this->backend->expects($this->at(1))
+			->method('removeReminder')
+			->with(1);
+		$this->backend->expects($this->at(2))
+			->method('removeReminder')
+			->with(2);
+		$this->backend->expects($this->at(3))
+			->method('removeReminder')
+			->with(3);
+		$this->backend->expects($this->at(4))
+			->method('removeReminder')
+			->with(4);
+		$this->backend->expects($this->at(5))
+			->method('insertReminder')
+			->with(1337, 42, 'wej2z68l9h', true, 1467849600, false, 'fbdb2726bc0f7dfacac1d881c1453e20', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1467848700, false)
+			->willReturn(99);
+
+		$this->backend->expects($this->at(6))
+			->method('insertReminder')
+			->with(1337, 42, 'wej2z68l9h', true, 1467849600, false, 'fbdb2726bc0f7dfacac1d881c1453e20', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1467848820, true)
+			->willReturn(99);
+		$this->backend->expects($this->at(7))
+			->method('insertReminder')
+			->with(1337, 42, 'wej2z68l9h', true, 1467849600, false, 'fbdb2726bc0f7dfacac1d881c1453e20', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1467848940, true)
+			->willReturn(99);
+		$this->backend->expects($this->at(8))
+			->method('insertReminder')
+			->with(1337, 42, 'wej2z68l9h', true, 1467849600, false, 'fbdb2726bc0f7dfacac1d881c1453e20', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1467849060, true)
+			->willReturn(99);
+		$this->backend->expects($this->at(9))
+			->method('insertReminder')
+			->with(1337, 42, 'wej2z68l9h', true, 1467849600, false, 'fbdb2726bc0f7dfacac1d881c1453e20', 'ecacbf07d413c3c78d1ac7ad8c469602', 'EMAIL', true, 1467849180, true)
+			->willReturn(99);
+		$this->backend->expects($this->at(10))
+			->method('removeReminder')
+			->with(5);
+		$this->backend->expects($this->at(11))
+			->method('insertReminder')
+			->with(1337, 42, 'wej2z68l9h', true, 1468454400, false, 'fbdb2726bc0f7dfacac1d881c1453e20', '8996992118817f9f311ac5cc56d1cc97', 'EMAIL', true, 1467763200, false)
+			->willReturn(99);
+
+		$this->timeFactory->method('getDateTime')
+			->willReturn(\DateTime::createFromFormat(\DateTime::ATOM, '2016-06-08T00:00:00+00:00'));
+
+		$this->reminderService->processReminders();
+	}
+}