24 files changed, 933 insertions, 16 deletions

diff --git a/.drone.yml b/.drone.yml
index d25ce0823..78fc3fea9 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -178,6 +178,43 @@ trigger:
 
 ---
 kind: pipeline
+name: int-sqlite-reaction
+
+steps:
+  - name: integration-reaction
+    image: ghcr.io/nextcloud/continuous-integration-php8.0:latest
+    environment:
+      APP_NAME: spreed
+      CORE_BRANCH: master
+      GUESTS_BRANCH: master
+      DATABASEHOST: sqlite
+    commands:
+      - bash tests/drone-run-integration-tests.sh || exit 0
+      - wget https://raw.githubusercontent.com/nextcloud/travis_ci/master/before_install.sh
+      - bash ./before_install.sh $APP_NAME $CORE_BRANCH $DATABASEHOST
+      - cd ../server
+      - git clone --depth 1 -b "$GUESTS_BRANCH" https://github.com/nextcloud/guests apps/guests
+      - ./occ app:enable $APP_NAME
+      - cd apps/$APP_NAME
+
+      # Run integration tests
+      - cd tests/integration/
+      - bash run.sh features/reaction
+
+services:
+  - name: cache
+    image: ghcr.io/nextcloud/continuous-integration-redis:latest
+
+trigger:
+  branch:
+    - master
+    - stable*
+  event:
+    - pull_request
+    - push
+
+---
+kind: pipeline
 name: int-sqlite-sharing
 
 steps:
@@ -477,6 +514,53 @@ trigger:
 
 ---
 kind: pipeline
+name: int-mysql-reaction
+
+steps:
+  - name: integration-reaction
+    image: ghcr.io/nextcloud/continuous-integration-php8.0:latest
+    environment:
+      APP_NAME: spreed
+      CORE_BRANCH: master
+      GUESTS_BRANCH: master
+      DATABASEHOST: mysql
+    commands:
+      - bash tests/drone-run-integration-tests.sh || exit 0
+      - wget https://raw.githubusercontent.com/nextcloud/travis_ci/master/before_install.sh
+      - bash ./before_install.sh $APP_NAME $CORE_BRANCH $DATABASEHOST
+      - cd ../server
+      - git clone --depth 1 -b "$GUESTS_BRANCH" https://github.com/nextcloud/guests apps/guests
+      - ./occ app:enable $APP_NAME
+      - cd apps/$APP_NAME
+
+      # Run integration tests
+      - cd tests/integration/
+      - bash run.sh features/reaction
+
+services:
+  - name: cache
+    image: ghcr.io/nextcloud/continuous-integration-redis:latest
+  - name: mysql
+    image: ghcr.io/nextcloud/continuous-integration-mariadb-10.4:10.4
+    environment:
+      MYSQL_ROOT_PASSWORD: owncloud
+      MYSQL_USER: oc_autotest
+      MYSQL_PASSWORD: owncloud
+      MYSQL_DATABASE: oc_autotest
+    command: [ "--innodb_large_prefix=true", "--innodb_file_format=barracuda", "--innodb_file_per_table=true" ]
+    tmpfs:
+      - /var/lib/mysql
+
+trigger:
+  branch:
+    - master
+    - stable*
+  event:
+#    - pull_request
+    - push
+
+---
+kind: pipeline
 name: int-mysql-sharing
 
 steps:
@@ -791,6 +875,52 @@ trigger:
 
 ---
 kind: pipeline
+name: int-pgsql-reaction
+
+steps:
+  - name: integration-reaction
+    image: ghcr.io/nextcloud/continuous-integration-php8.0:latest
+    environment:
+      APP_NAME: spreed
+      CORE_BRANCH: master
+      GUESTS_BRANCH: master
+      DATABASEHOST: pgsql
+    commands:
+      - bash tests/drone-run-integration-tests.sh || exit 0
+      - wget https://raw.githubusercontent.com/nextcloud/travis_ci/master/before_install.sh
+      - bash ./before_install.sh $APP_NAME $CORE_BRANCH $DATABASEHOST
+      - cd ../server
+      - git clone --depth 1 -b "$GUESTS_BRANCH" https://github.com/nextcloud/guests apps/guests
+      - ./occ app:enable $APP_NAME
+      - cd apps/$APP_NAME
+
+      # Run integration tests
+      - cd tests/integration/
+      - bash run.sh features/reaction
+
+services:
+  - name: cache
+    image: ghcr.io/nextcloud/continuous-integration-redis:latest
+  - name: pgsql
+    image: ghcr.io/nextcloud/continuous-integration-postgres-13:postgres-13
+    environment:
+      POSTGRES_USER: oc_autotest
+      POSTGRES_DB: oc_autotest_dummy
+      POSTGRES_HOST_AUTH_METHOD: trust
+      POSTGRES_PASSWORD:
+    tmpfs:
+      - /var/lib/postgresql/data
+
+trigger:
+  branch:
+    - master
+    - stable*
+  event:
+#    - pull_request
+    - push
+
+---
+kind: pipeline
 name: int-pgsql-sharing
 
 steps:
diff --git a/appinfo/routes.php b/appinfo/routes.php
index e888b7006..fde29617e 100644
--- a/appinfo/routes.php
+++ b/appinfo/routes.php
@@ -36,6 +36,7 @@ return array_merge_recursive(
 	include(__DIR__ . '/routes/routesMatterbridgeSettingsController.php'),
 	include(__DIR__ . '/routes/routesPageController.php'),
 	include(__DIR__ . '/routes/routesPublicShareAuthController.php'),
+	include(__DIR__ . '/routes/routesReactionController.php'),
 	include(__DIR__ . '/routes/routesRoomController.php'),
 	include(__DIR__ . '/routes/routesSettingsController.php'),
 	include(__DIR__ . '/routes/routesSignalingController.php'),
diff --git a/appinfo/routes/routesReactionController.php b/appinfo/routes/routesReactionController.php
new file mode 100644
index 000000000..375478e3f
--- /dev/null
+++ b/appinfo/routes/routesReactionController.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2021 Vitor Mattos <vitor@php.rio>
+ *
+ * @author Vitor Mattos <vitor@php.rio>
+ *
+ * @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/>.
+ *
+ */
+
+return [
+	'ocs' => [
+		['name' => 'Reaction#react', 'url' => '/api/{apiVersion}/reaction/{token}/{messageId}', 'verb' => 'POST', 'requirements' => [
+			'apiVersion' => 'v1',
+			'token' => '^[a-z0-9]{4,30}$',
+		]],
+		['name' => 'Reaction#delete', 'url' => '/api/{apiVersion}/reaction/{token}/{messageId}', 'verb' => 'DELETE', 'requirements' => [
+			'apiVersion' => 'v1',
+			'token' => '^[a-z0-9]{4,30}$',
+		]],
+		['name' => 'Reaction#getReactions', 'url' => '/api/{apiVersion}/reaction/{token}/{messageId}', 'verb' => 'GET', 'requirements' => [
+			'apiVersion' => 'v1',
+			'token' => '^[a-z0-9]{4,30}$',
+		]],
+	],
+];
diff --git a/docs/capabilities.md b/docs/capabilities.md
index 489ec3416..9ef1de814 100644
--- a/docs/capabilities.md
+++ b/docs/capabilities.md
@@ -89,3 +89,4 @@ title: Capabilities
 
 ## 14
 * `chat-unread` - Whether the API to mark a conversation as unread is available
+* `reactions` - Api reactions to chat message
diff --git a/docs/chat.md b/docs/chat.md
index ff03979ef..07c3660b1 100644
--- a/docs/chat.md
+++ b/docs/chat.md
@@ -50,6 +50,7 @@ Base endpoint is: `/ocs/v2.php/apps/spreed/api/v1`
         `message` | string | Message string with placeholders (see [Rich Object String](https://github.com/nextcloud/server/issues/1706))
         `messageParameters` | array | Message parameters for `message` (see [Rich Object String](https://github.com/nextcloud/server/issues/1706))
         `parent` | array | **Optional:** See `Parent data` below
+        `reactions` | array | **Optional:** An array map with relation between reaction emoji and total count of reactions with this emoji
 
 #### Parent data
 
@@ -324,3 +325,4 @@ See [OCP\RichObjectStrings\Definitions](https://github.com/nextcloud/server/blob
 * `matterbridge_config_removed` - {actor} removed the Matterbridge configuration
 * `matterbridge_config_enabled` - {actor} started Matterbridge
 * `matterbridge_config_disabled` - {actor} stopped Matterbridge
+
diff --git a/docs/index.md b/docs/index.md
index 0e19b823f..3e1dec1dc 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -16,6 +16,7 @@
 * [Participant API](participant.md)
 * [Call API](call.md)
 * [Chat API](chat.md)
+* [Reaction API](reaction.md)
 * [Webinar API](webinar.md)
 * [Internal Signaling API](internal-signaling.md)
 * [Standalone Signaling API](https://nextcloud-spreed-signaling.readthedocs.io/en/latest/)
diff --git a/docs/reaction.md b/docs/reaction.md
new file mode 100644
index 000000000..5fc16e9f6
--- /dev/null
+++ b/docs/reaction.md
@@ -0,0 +1,66 @@
+# Reaction API
+
+Base endpoint is: `/ocs/v2.php/apps/spreed/api/v1`
+
+## React to a message
+
+* Required capability: `reactions`
+* Method: `POST`
+* Endpoint: `/reaction/{token}/{messageId}`
+* Data:
+
+    field | type | Description
+    ---|---|---
+    `reaction` | string | the reaction emoji
+
+* Response:
+    - Status code:
+        + `200 OK` Reaction already exists
+        + `201 Created`
+        + `400 Bad Request` In case of no reaction support, message out of reactions context or any other error
+        + `404 Not Found` When the conversation or message to react could not be found for the participant
+        + `409 Conflict` User already did this reaction to this message
+
+## Delete a reaction
+
+* Required capability: `reactions`
+* Method: `DELETE`
+* Endpoint: `/reaction/{token}/{messageId}`
+* Data:
+
+    field | type | Description
+    ---|---|---
+    `reaction` | string | the reaction emoji
+
+* Response:
+    - Status code:
+        + `201 Created`
+        + `400 Bad Request` In case of no reaction support, message out of reactions context or any other error
+        + `404 Not Found` When the conversation or message to react or reaction could not be found for the participant
+
+## Retrieve reactions of a message by type
+
+* Required capability: `reactions`
+* Method: `GET`
+* Endpoint: `/reaction/{token}/{messageId}`
+* Data:
+
+    field | type | Description
+    ---|---|---
+    `reaction` | string | **Optional:** the reaction emoji
+
+* Response:
+    - Status code:
+        + `200 OK`
+        + `400 Bad Request` In case of no reaction support, message out of reactions context or any other error
+        + `404 Not Found` When the conversation or message to react could not be found for the participant
+
+    - Data:
+        Array with data of reactions:
+
+        field | type | Description
+        ---|---|---
+        `actorType` | string | `guests` or `users`
+        `actorId` | string | Actor id of the reacting participant
+        `actorDisplayName` | string | Display name of the reaction author
+        `timestamp` | int | Timestamp in seconds and UTC time zone
diff --git a/lib/Capabilities.php b/lib/Capabilities.php
index c4742a38d..f8426d58f 100644
--- a/lib/Capabilities.php
+++ b/lib/Capabilities.php
@@ -27,6 +27,7 @@ namespace OCA\Talk;
 
 use OCA\Talk\Chat\ChatManager;
 use OCP\Capabilities\IPublicCapability;
+use OCP\Comments\ICommentsManager;
 use OCP\IConfig;
 use OCP\IUser;
 use OCP\IUserSession;
@@ -37,14 +38,18 @@ class Capabilities implements IPublicCapability {
 	protected $serverConfig;
 	/** @var Config */
 	protected $talkConfig;
+	/** @var ICommentsManager */
+	protected $commentsManager;
 	/** @var IUserSession */
 	protected $userSession;
 
 	public function __construct(IConfig $serverConfig,
 								Config $talkConfig,
+								ICommentsManager $commentsManager,
 								IUserSession $userSession) {
 		$this->serverConfig = $serverConfig;
 		$this->talkConfig = $talkConfig;
+		$this->commentsManager = $commentsManager;
 		$this->userSession = $userSession;
 	}
 
@@ -115,6 +120,10 @@ class Capabilities implements IPublicCapability {
 			],
 		];
 
+		if ($this->commentsManager->supportReactions()) {
+			$capabilities['features'][] = 'reactions';
+		}
+
 		if ($user instanceof IUser) {
 			$capabilities['config']['attachments']['folder'] = $this->talkConfig->getAttachmentFolder($user->getUID());
 			$capabilities['config']['chat']['read-privacy'] = $this->talkConfig->getUserReadPrivacy($user->getUID());
diff --git a/lib/Chat/Notifier.php b/lib/Chat/Notifier.php
index 83b45ac4c..e8428ebba 100644
--- a/lib/Chat/Notifier.php
+++ b/lib/Chat/Notifier.php
@@ -200,10 +200,11 @@ class Notifier {
 	 * @param Room $chat
 	 * @param IComment $comment
 	 * @param IComment $replyTo
+	 * @param string $subject
 	 * @return array[] Actor that was replied to
 	 * @psalm-return array<int, array{id: string, type: string}>
 	 */
-	public function notifyReplyToAuthor(Room $chat, IComment $comment, IComment $replyTo): array {
+	public function notifyReplyToAuthor(Room $chat, IComment $comment, IComment $replyTo, string $subject = 'reply'): array {
 		if ($replyTo->getActorType() !== Attendee::ACTOR_USERS) {
 			// No reply notification when the replyTo-author was not a user
 			return [];
@@ -213,7 +214,7 @@ class Notifier {
 			return [];
 		}
 
-		$notification = $this->createNotification($chat, $comment, 'reply');
+		$notification = $this->createNotification($chat, $comment, $subject);
 		$notification->setUser($replyTo->getActorId());
 		$this->notificationManager->notify($notification);
 
@@ -266,6 +267,34 @@ class Notifier {
 		}
 	}
 
+	public function notifyReacted(Room $chat, IComment $comment, IComment $reaction): void {
+		if ($comment->getActorType() !== Attendee::ACTOR_USERS) {
+			return;
+		}
+
+		if ($comment->getActorType() === $reaction->getActorType() && $comment->getActorId() === $reaction->getActorId()) {
+			return;
+		}
+
+		$participant = $chat->getParticipant($comment->getActorId(), false);
+		$notificationLevel = $participant->getAttendee()->getNotificationLevel();
+		if ($notificationLevel === Participant::NOTIFY_DEFAULT) {
+			if ($chat->getType() === Room::TYPE_ONE_TO_ONE) {
+				$notificationLevel = Participant::NOTIFY_ALWAYS;
+			} else {
+				$notificationLevel = $this->getDefaultGroupNotification();
+			}
+		}
+
+		if ($notificationLevel === Participant::NOTIFY_ALWAYS) {
+			$notification = $this->createNotification($chat, $comment, 'reaction', [
+				'reaction' => $reaction->getMessage(),
+			]);
+			$notification->setUser($comment->getActorId());
+			$this->notificationManager->notify($notification);
+		}
+	}
+
 	/**
 	 * Removes all the pending notifications for the room with the given ID.
 	 *
@@ -363,17 +392,18 @@ class Notifier {
 	 * @param Room $chat
 	 * @param IComment $comment
 	 * @param string $subject
+	 * @param array $subjectData
 	 * @return INotification
 	 */
-	private function createNotification(Room $chat, IComment $comment, string $subject): INotification {
+	private function createNotification(Room $chat, IComment $comment, string $subject, array $subjectData = []): INotification {
+		$subjectData['userType'] = $comment->getActorType();
+		$subjectData['userId'] = $comment->getActorId();
+
 		$notification = $this->notificationManager->createNotification();
 		$notification
 			->setApp('spreed')
 			->setObject('chat', $chat->getToken())
-			->setSubject($subject, [
-				'userType' => $comment->getActorType(),
-				'userId' => $comment->getActorId(),
-			])
+			->setSubject($subject, $subjectData)
 			->setMessage($comment->getVerb(), [
 				'commentId' => $comment->getId(),
 			])
diff --git a/lib/Chat/Parser/Listener.php b/lib/Chat/Parser/Listener.php
index 83e26f673..ebb63fe22 100644
--- a/lib/Chat/Parser/Listener.php
+++ b/lib/Chat/Parser/Listener.php
@@ -100,6 +100,18 @@ class Listener {
 		$dispatcher->addListener(MessageParser::EVENT_MESSAGE_PARSE, static function (ChatMessageEvent $event) {
 			$chatMessage = $event->getMessage();
 
+			if ($chatMessage->getMessageType() !== 'reaction' && $chatMessage->getMessageType() !== 'reaction_deleted') {
+				return;
+			}
+
+			/** @var ReactionParser $parser */
+			$parser = \OC::$server->get(ReactionParser::class);
+			$parser->parseMessage($chatMessage);
+		});
+
+		$dispatcher->addListener(MessageParser::EVENT_MESSAGE_PARSE, static function (ChatMessageEvent $event) {
+			$chatMessage = $event->getMessage();
+
 			if ($chatMessage->getMessageType() !== 'comment_deleted') {
 				return;
 			}
diff --git a/lib/Chat/Parser/ReactionParser.php b/lib/Chat/Parser/ReactionParser.php
new file mode 100644
index 000000000..7e38e0f78
--- /dev/null
+++ b/lib/Chat/Parser/ReactionParser.php
@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2021 Vitor Mattos <vitor@php.rio>
+ *
+ * @author Vitor Mattos <vitor@php.rio>
+ *
+ * @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\Talk\Chat\Parser;
+
+use OCA\Talk\Model\Message;
+use OCP\IL10N;
+
+class ReactionParser {
+	/** @var IL10N|null */
+	private $l;
+	/**
+	 * @param Message $message
+	 * @throws \OutOfBoundsException
+	 */
+	public function parseMessage(Message $message): void {
+		$comment = $message->getComment();
+		if (!in_array($comment->getVerb(), ['reaction', 'reaction_deleted'])) {
+			throw new \OutOfBoundsException('Not a reaction');
+		}
+		$this->l = $message->getL10n();
+		$message->setMessageType('system');
+		if ($comment->getVerb() === 'reaction_deleted') {
+			// This message is necessary to make compatible with old clients
+			$message->setMessage($this->l->t('Message deleted by author'), [], $comment->getVerb());
+		} else {
+			$message->setMessage($message->getMessage(), [], $comment->getVerb());
+		}
+	}
+}
diff --git a/lib/Chat/ReactionManager.php b/lib/Chat/ReactionManager.php
new file mode 100644
index 000000000..4b4576ea4
--- /dev/null
+++ b/lib/Chat/ReactionManager.php
@@ -0,0 +1,153 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2021 Vitor Mattos <vitor@php.rio>
+ *
+ * @author Vitor Mattos <vitor@php.rio>
+ *
+ * @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\Talk\Chat;
+
+use OCA\Talk\Exceptions\ReactionAlreadyExistsException;
+use OCA\Talk\Exceptions\ReactionNotSupportedException;
+use OCA\Talk\Exceptions\ReactionOutOfContextException;
+use OCA\Talk\Participant;
+use OCA\Talk\Room;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\Comments\IComment;
+use OCP\Comments\ICommentsManager;
+use OCP\Comments\NotFoundException;
+use OCP\IL10N;
+
+class ReactionManager {
+	/** @var ICommentsManager|CommentsManager */
+	private $commentsManager;
+	/** @var IL10N */
+	private $l;
+	/** @var MessageParser */
+	private $messageParser;
+	/** @var Notifier */
+	private $notifier;
+	/** @var ITimeFactory */
+	protected $timeFactory;
+
+	public function __construct(CommentsManager $commentsManager,
+								IL10N $l,
+								MessageParser $messageParser,
+								Notifier $notifier,
+								ITimeFactory $timeFactory) {
+		$this->commentsManager = $commentsManager;
+		$this->l = $l;
+		$this->messageParser = $messageParser;
+		$this->notifier = $notifier;
+		$this->timeFactory = $timeFactory;
+	}
+
+	public function addReactionMessage(Room $chat, Participant $participant, IComment $parentMessage, string $reaction): IComment {
+		try {
+			// Check if the user already reacted with the same reaction
+			$comment = $this->commentsManager->getReactionComment(
+				(int) $parentMessage->getId(),
+				$participant->getAttendee()->getActorType(),
+				$participant->getAttendee()->getActorId(),
+				$reaction
+			);
+			throw new ReactionAlreadyExistsException();
+		} catch (NotFoundException $e) {
+		}
+
+		$comment = $this->commentsManager->create(
+			$participant->getAttendee()->getActorType(),
+			$participant->getAttendee()->getActorId(),
+			'chat',
+			(string) $chat->getId()
+		);
+		$comment->setParentId((string) $parentMessage->getId());
+		$comment->setMessage($reaction);
+		$comment->setVerb('reaction');
+		$this->commentsManager->save($comment);
+
+		$this->notifier->notifyReacted($chat, $parentMessage, $comment);
+		return $comment;
+	}
+
+	public function deleteReactionMessage(Participant $participant, int $messageId, string $reaction): IComment {
+		$comment = $this->commentsManager->getReactionComment(
+			$messageId,
+			$participant->getAttendee()->getActorType(),
+			$participant->getAttendee()->getActorId(),
+			$reaction
+		);
+		$comment->setMessage(
+			json_encode([
+				'deleted_by_type' => $participant->getAttendee()->getActorType(),
+				'deleted_by_id' => $participant->getAttendee()->getActorId(),
+				'deleted_on' => $this->timeFactory->getDateTime()->getTimestamp(),
+			])
+		);
+		$comment->setVerb('reaction_deleted');
+		$this->commentsManager->save($comment);
+		return $comment;
+	}
+
+	public function retrieveReactionMessages(Room $chat, Participant $participant, int $messageId, ?string $reaction): array {
+		if ($reaction) {
+			$comments = $this->commentsManager->retrieveAllReactionsWithSpecificReaction($messageId, $reaction);
+		} else {
+			$comments = $this->commentsManager->retrieveAllReactions($messageId);
+		}
+
+		foreach ($comments as $comment) {
+			$message = $this->messageParser->createMessage($chat, $participant, $comment, $this->l);
+			$this->messageParser->parseMessage($message);
+
+			$reactions[$comment->getMessage()][] = [
+				'actorType' => $comment->getActorType(),
+				'actorId' => $comment->getActorId(),
+				'actorDisplayName' => $message->getActorDisplayName(),
+				'timestamp' => $comment->getCreationDateTime()->getTimestamp(),
+			];
+		}
+		return $reactions;
+	}
+
+	/**
+	 * @param Room $chat
+	 * @param string $messageId
+	 * @return IComment
+	 * @throws NotFoundException
+	 * @throws ReactionNotSupportedException
+	 * @throws ReactionOutOfContextException
+	 */
+	public function getCommentToReact(Room $chat, string $messageId): IComment {
+		if (!$this->commentsManager->supportReactions()) {
+			throw new ReactionNotSupportedException();
+		}
+		$comment = $this->commentsManager->get($messageId);
+
+		if ($comment->getObjectType() !== 'chat'
+			|| $comment->getObjectId() !== (string) $chat->getId()
+			|| $comment->getVerb() !== 'comment') {
+			throw new ReactionOutOfContextException();
+		}
+
+		return $comment;
+	}
+}
diff --git a/lib/Controller/ReactionController.php b/lib/Controller/ReactionController.php
new file mode 100644
index 000000000..a16820ade
--- /dev/null
+++ b/lib/Controller/ReactionController.php
@@ -0,0 +1,130 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2021 Vitor Mattos <vitor@php.rio>
+ *
+ * @author Vitor Mattos <vitor@php.rio>
+ *
+ * @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\Talk\Controller;
+
+use OCA\Talk\Chat\ReactionManager;
+use OCA\Talk\Exceptions\ReactionAlreadyExistsException;
+use OCA\Talk\Exceptions\ReactionNotSupportedException;
+use OCA\Talk\Exceptions\ReactionOutOfContextException;
+use OCP\AppFramework\Http;
+use OCP\AppFramework\Http\DataResponse;
+use OCP\Comments\NotFoundException;
+use OCP\IRequest;
+
+class ReactionController extends AEnvironmentAwareController {
+	/** @var ReactionManager */
+	private $reactionManager;
+
+	public function __construct(string $appName,
+								IRequest $request,
+								ReactionManager $reactionManager) {
+		parent::__construct($appName, $request);
+		$this->reactionManager = $reactionManager;
+	}
+
+	/**
+	 * @NoAdminRequired
+	 * @RequireParticipant
+	 * @RequireReadWriteConversation
+	 * @RequireModeratorOrNoLobby
+	 *
+	 * @param int $messageId for reaction
+	 * @param string $reaction the reaction emoji
+	 * @return DataResponse
+	 */
+	public function react(int $messageId, string $reaction): DataResponse {
+		try {
+			$chat = $this->getRoom();
+			$participant = $this->getParticipant();
+			$parentMessage = $this->reactionManager->getCommentToReact($chat, (string) $messageId);
+			$this->reactionManager->addReactionMessage($chat, $participant, $parentMessage, $reaction);
+		} catch (NotFoundException $e) {
+			return new DataResponse([], Http::STATUS_NOT_FOUND);
+		} catch (ReactionAlreadyExistsException $e) {
+			return new DataResponse([], Http::STATUS_OK);
+		} catch (ReactionNotSupportedException | ReactionOutOfContextException | \Exception $e) {
+			return new DataResponse([], Http::STATUS_BAD_REQUEST);
+		}
+		return new DataResponse([], Http::STATUS_CREATED);
+	}
+
+	/**
+	 * @NoAdminRequired
+	 * @RequireParticipant
+	 * @RequireReadWriteConversation
+	 * @RequireModeratorOrNoLobby
+	 *
+	 * @param int $messageId for reaction
+	 * @param string $reaction the reaction emoji
+	 * @return DataResponse
+	 */
+	public function delete(int $messageId, string $reaction): DataResponse {
+		$participant = $this->getParticipant();
+		try {
+			// Verify that messageId is part of the room
+			$this->reactionManager->getCommentToReact($this->getRoom(), (string) $messageId);
+		} catch (ReactionNotSupportedException | ReactionOutOfContextException | NotFoundException $e) {
+			return new DataResponse([], Http::STATUS_NOT_FOUND);
+		}
+
+		try {
+			$this->reactionManager->deleteReactionMessage(
+				$participant,
+				$messageId,
+				$reaction
+			);
+		} catch (NotFoundException $e) {
+			return new DataResponse([], Http::STATUS_NOT_FOUND);
+		} catch (\Exception $e) {
+			return new DataResponse([], Http::STATUS_BAD_REQUEST);
+		}
+
+		return new DataResponse([], Http::STATUS_OK);
+	}
+
+	/**
+	 * @NoAdminRequired
+	 * @RequireParticipant
+	 * @RequireReadWriteConversation
+	 * @RequireModeratorOrNoLobby
+	 *
+	 * @param int $messageId for reaction
+	 * @param string|null $reaction the reaction emoji
+	 * @return DataResponse
+	 */
+	public function getReactions(int $messageId, ?string $reaction): DataResponse {
+		try {
+			// Verify that messageId is part of the room
+			$this->reactionManager->getCommentToReact($this->getRoom(), (string) $messageId);
+		} catch (ReactionNotSupportedException | ReactionOutOfContextException | NotFoundException $e) {
+			return new DataResponse([], Http::STATUS_NOT_FOUND);
+		}
+
+		$reactions = $this->reactionManager->retrieveReactionMessages($this->getRoom(), $this->getParticipant(), $messageId, $reaction);
+
+		return new DataResponse($reactions, Http::STATUS_OK);
+	}
+}
diff --git a/lib/Exceptions/ReactionAlreadyExistsException.php b/lib/Exceptions/ReactionAlreadyExistsException.php
new file mode 100644
index 000000000..399856d9b
--- /dev/null
+++ b/lib/Exceptions/ReactionAlreadyExistsException.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2021 Vitor Mattos <vitor@php.rio>
+ *
+ * @author Vitor Mattos <vitor@php.rio>
+ *
+ * @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\Talk\Exceptions;
+
+class ReactionAlreadyExistsException extends \OutOfBoundsException {
+}
diff --git a/lib/Exceptions/ReactionNotSupportedException.php b/lib/Exceptions/ReactionNotSupportedException.php
new file mode 100644
index 000000000..478f6a80a
--- /dev/null
+++ b/lib/Exceptions/ReactionNotSupportedException.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2022, Vitor Mattos <vitor@php.rio>
+ *
+ * @author Vitor Mattos <vitor@php.rio>
+ *
+ * @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\Talk\Exceptions;
+
+class ReactionNotSupportedException extends \Exception {
+}
diff --git a/lib/Exceptions/ReactionOutOfContextException.php b/lib/Exceptions/ReactionOutOfContextException.php
new file mode 100644
index 000000000..499dee69b
--- /dev/null
+++ b/lib/Exceptions/ReactionOutOfContextException.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2022, Vitor Mattos <vitor@php.rio>
+ *
+ * @author Vitor Mattos <vitor@php.rio>
+ *
+ * @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\Talk\Exceptions;
+
+class ReactionOutOfContextException extends \Exception {
+}
diff --git a/lib/Manager.php b/lib/Manager.php
index c3bb42004..993ade134 100644
--- a/lib/Manager.php
+++ b/lib/Manager.php
@@ -233,6 +233,7 @@ class Manager {
 			'reference_id' => $row['comment_reference_id'] ?? null,
 			'creation_timestamp' => $row['comment_creation_timestamp'],
 			'latest_child_timestamp' => $row['comment_latest_child_timestamp'],
+			'reactions' => $row['comment_reactions'],
 		]);
 	}
 
@@ -1185,5 +1186,6 @@ class Manager {
 		}
 		$query->selectAlias('c.creation_timestamp', 'comment_creation_timestamp');
 		$query->selectAlias('c.latest_child_timestamp', 'comment_latest_child_timestamp');
+		$query->selectAlias('c.reactions', 'comment_reactions');
 	}
 }
diff --git a/lib/Model/Message.php b/lib/Model/Message.php
index 30f1fa6d9..118adad72 100644
--- a/lib/Model/Message.php
+++ b/lib/Model/Message.php
@@ -163,6 +163,7 @@ class Message {
 		return $this->getMessageType() !== 'system' &&
 			$this->getMessageType() !== 'command' &&
 			$this->getMessageType() !== 'comment_deleted' &&
+			$this->getMessageType() !== 'reaction' &&
 			\in_array($this->getActorType(), [Attendee::ACTOR_USERS, Attendee::ACTOR_GUESTS]);
 	}
 
@@ -180,6 +181,7 @@ class Message {
 			'messageType' => $this->getMessageType(),
 			'isReplyable' => $this->isReplyable(),
 			'referenceId' => (string) $this->getComment()->getReferenceId(),
+			'reactions' => $this->getComment()->getReactions(),
 		];
 
 		if ($this->getMessageType() === 'comment_deleted') {
diff --git a/lib/Notification/Notifier.php b/lib/Notification/Notifier.php
index e1100880f..529df5198 100644
--- a/lib/Notification/Notifier.php
+++ b/lib/Notification/Notifier.php
@@ -260,7 +260,7 @@ class Notifier implements INotifier {
 			}
 			return $this->parseCall($notification, $room, $l);
 		}
-		if ($subject === 'reply' || $subject === 'mention' || $subject === 'chat') {
+		if ($subject === 'reply' || $subject === 'mention' || $subject === 'chat' || $subject === 'reaction') {
 			return $this->parseChatMessage($notification, $room, $participant, $l);
 		}
 
@@ -456,6 +456,27 @@ class Notifier implements INotifier {
 					$subject = $l->t('A guest replied to your message in conversation {call}');
 				}
 			}
+		} elseif ($notification->getSubject() === 'reaction') {
+			$richSubjectParameters['reaction'] = [
+				'type' => 'highlight',
+				'id' => $subjectParameters['reaction'],
+				'name' => $subjectParameters['reaction'],
+			];
+
+			if ($room->getType() === Room::TYPE_ONE_TO_ONE) {
+				$subject = $l->t('{user} reacted with {reaction} to your private message');
+			} elseif ($richSubjectUser) {
+				$subject = $l->t('{user} reacted with {reaction} to your message in conversation {call}');
+			} elseif (!$isGuest) {
+				$subject = $l->t('A deleted user reacted with {reaction} to your message in conversation {call}');
+			} else {
+				try {
+					$richSubjectParameters['guest'] = $this->getGuestParameter($room, $comment->getActorId());
+					$subject = $l->t('{guest} (guest) reacted with {reaction} to your message in conversation {call}');
+				} catch (ParticipantNotFoundException $e) {
+					$subject = $l->t('A guest reacted with {reaction} to your message in conversation {call}');
+				}
+			}
 		} elseif ($room->getType() === Room::TYPE_ONE_TO_ONE) {
 			$subject = $l->t('{user} mentioned you in a private conversation');
 		} elseif ($richSubjectUser) {
diff --git a/mkdocs.yml b/mkdocs.yml
index 28860dae3..d83858d64 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -26,6 +26,7 @@ nav:
       - 'Participants management': 'participant.md'
       - 'Call management': 'call.md'
       - 'Chat management': 'chat.md'
+      - 'Reaction management': 'reaction.md'
       - 'Webinar management': 'webinar.md'
       - 'Settings': 'settings.md'
       - 'Integration by other apps': 'integration.md'
diff --git a/tests/integration/features/bootstrap/FeatureContext.php b/tests/integration/features/bootstrap/FeatureContext.php
index 58814dd15..3bdca6641 100644
--- a/tests/integration/features/bootstrap/FeatureContext.php
+++ b/tests/integration/features/bootstrap/FeatureContext.php
@@ -447,8 +447,8 @@ class FeatureContext implements Context, SnippetAcceptingContext {
 				return $attendee;
 			}, $result);
 
-			usort($expected, [$this, 'sortAttendees']);
-			usort($result, [$this, 'sortAttendees']);
+			usort($expected, [self::class, 'sortAttendees']);
+			usort($result, [self::class, 'sortAttendees']);
 
 			Assert::assertEquals($expected, $result);
 		} else {
@@ -477,7 +477,7 @@ class FeatureContext implements Context, SnippetAcceptingContext {
 		}
 	}
 
-	protected function sortAttendees(array $a1, array $a2): int {
+	protected static function sortAttendees(array $a1, array $a2): int {
 		if (array_key_exists('participantType', $a1) && array_key_exists('participantType', $a2) && $a1['participantType'] !== $a2['participantType']) {
 			return $a1['participantType'] <=> $a2['participantType'];
 		}
@@ -1559,6 +1559,7 @@ class FeatureContext implements Context, SnippetAcceptingContext {
 		}
 		$includeParents = in_array('parentMessage', $formData->getRow(0), true);
 		$includeReferenceId = in_array('referenceId', $formData->getRow(0), true);
+		$includeReactions = in_array('reactions', $formData->getRow(0), true);
 
 		$count = count($formData->getHash());
 		Assert::assertCount($count, $messages, 'Message count does not match');
@@ -1567,7 +1568,7 @@ class FeatureContext implements Context, SnippetAcceptingContext {
 				$messages[$i]['messageParameters'] = 'IGNORE';
 			}
 		}
-		Assert::assertEquals($formData->getHash(), array_map(function ($message) use ($includeParents, $includeReferenceId) {
+		Assert::assertEquals($formData->getHash(), array_map(function ($message) use ($includeParents, $includeReferenceId, $includeReactions) {
 			$data = [
 				'room' => self::$tokenToIdentifier[$message['token']],
 				'actorType' => $message['actorType'],
@@ -1584,6 +1585,9 @@ class FeatureContext implements Context, SnippetAcceptingContext {
 			if ($includeReferenceId) {
 				$data['referenceId'] = $message['referenceId'];
 			}
+			if ($includeReactions) {
+				$data['reactions'] = json_encode($message['reactions'], JSON_UNESCAPED_UNICODE);
+			}
 			return $data;
 		}, $messages));
 	}
@@ -2079,6 +2083,57 @@ class FeatureContext implements Context, SnippetAcceptingContext {
 		$this->setCurrentUser($currentUser);
 	}
 
+	/**
+	 * @Given /^user "([^"]*)" (delete react|react) with "([^"]*)" on message "([^"]*)" to room "([^"]*)" with (\d+)(?: \((v1)\))?$/
+	 */
+	public function userReactWithOnMessageToRoomWith(string $user, string $action, string $reaction, string $message, string $identifier, int $statusCode, string $apiVersion = 'v1'): void {
+		$token = self::$identifierToToken[$identifier];
+		$messageId = self::$messages[$message];
+		$this->setCurrentUser($user);
+		$verb = $action === 'react' ? 'POST' : 'DELETE';
+		$this->sendRequest($verb, '/apps/spreed/api/' . $apiVersion . '/reaction/' . $token . '/' . $messageId, [
+			'reaction' => $reaction
+		]);
+		$this->assertStatusCode($this->response, $statusCode);
+	}
+
+	/**
+	 * @Given /^user "([^"]*)" retrieve reactions "([^"]*)" of message "([^"]*)" in room "([^"]*)" with (\d+)(?: \((v1)\))?$/
+	 */
+	public function userRetrieveReactionsOfMessageInRoomWith(string $user, string $reaction, string $message, string $identifier, int $statusCode, string $apiVersion = 'v1', TableNode $formData): void {
+		$token = self::$identifierToToken[$identifier];
+		$messageId = self::$messages[$message];
+		$this->setCurrentUser($user);
+		$reaction = $reaction !== 'all' ? '?reaction=' . $reaction : '';
+		$this->sendRequest('GET', '/apps/spreed/api/' . $apiVersion . '/reaction/' . $token . '/' . $messageId . $reaction);
+		$this->assertStatusCode($this->response, $statusCode);
+		$this->assertReactionList($formData);
+	}
+
+	private function assertReactionList(TableNode $formData): void {
+		$expected = [];
+		foreach ($formData->getHash() as $row) {
+			$reaction = $row['reaction'];
+			unset($row['reaction']);
+			$expected[$reaction][] = $row;
+		}
+
+		$result = $this->getDataFromResponse($this->response);
+		$result = array_map(static function ($reaction, $list) use ($expected): array {
+			$list = array_map(function ($reaction) {
+				unset($reaction['timestamp']);
+				return $reaction;
+			}, $list);
+			Assert::assertCount(count($list), $expected[$reaction], 'Reaction count by type does not match');
+
+			usort($expected[$reaction], [self::class, 'sortAttendees']);
+			usort($list, [self::class, 'sortAttendees']);
+			Assert::assertEquals($expected[$reaction], $list, 'Reaction list by type does not match');
+			return $list;
+		}, array_keys($result), array_values($result));
+		Assert::assertCount(count($expected), $result, 'Reaction count does not match');
+	}
+
 	/*
 	 * Requests
 	 */
diff --git a/tests/integration/features/reaction/react.feature b/tests/integration/features/reaction/react.feature
new file mode 100644
index 000000000..e95805816
--- /dev/null
+++ b/tests/integration/features/reaction/react.feature
@@ -0,0 +1,68 @@
+Feature: reaction/react
+  Background:
+    Given user "participant1" exists
+    Given user "participant2" exists
+
+  Scenario: React to message with success
+    Given user "participant1" creates room "room" (v4)
+      | roomType | 3 |
+      | roomName | room |
+    And user "participant1" adds user "participant2" to room "room" with 200 (v4)
+    And user "participant1" sends message "Message 1" to room "room" with 201
+    And user "participant2" react with "👍" on message "Message 1" to room "room" with 201
+    Then user "participant1" sees the following messages in room "room" with 200
+      | room | actorType | actorId      | actorDisplayName         | message   | messageParameters | reactions |
+      | room | users     | participant1 | participant1-displayname | Message 1 | []                | {"👍":1}  |
+    And user "participant1" react with "👍" on message "Message 1" to room "room" with 201
+    Then user "participant1" sees the following messages in room "room" with 200
+      | room | actorType | actorId      | actorDisplayName         | message   | messageParameters | reactions |
+      | room | users     | participant1 | participant1-displayname | Message 1 | []                | {"👍":2}  |
+
+  Scenario: React two times to same message with the same reaction
+    Given user "participant1" creates room "room" (v4)
+      | roomType | 3 |
+      | roomName | room |
+    And user "participant1" adds user "participant2" to room "room" with 200 (v4)
+    And user "participant1" sends message "Message 1" to room "room" with 201
+    And user "participant2" react with "👍" on message "Message 1" to room "room" with 201
+    And user "participant2" react with "👍" on message "Message 1" to room "room" with 200
+    Then user "participant1" sees the following messages in room "room" with 200
+      | room | actorType | actorId      | actorDisplayName         | message   | messageParameters | reactions |
+      | room | users     | participant1 | participant1-displayname | Message 1 | []                | {"👍":1}  |
+
+  Scenario: Delete reaction to message with success
+    Given user "participant1" creates room "room" (v4)
+      | roomType | 3 |
+      | roomName | room |
+    And user "participant1" adds user "participant2" to room "room" with 200 (v4)
+    And user "participant1" sends message "Message 1" to room "room" with 201
+    And user "participant2" react with "👍" on message "Message 1" to room "room" with 201
+    Then user "participant1" sees the following messages in room "room" with 200
+      | room | actorType | actorId      | actorDisplayName         | message   | messageParameters | reactions |
+      | room | users     | participant1 | participant1-displayname | Message 1 | []                | {"👍":1}  |
+    And user "participant2" delete react with "👍" on message "Message 1" to room "room" with 200
+    Then user "participant1" sees the following messages in room "room" with 200
+      | room | actorType | actorId      | actorDisplayName         | message   | messageParameters | reactions |
+      | room | users     | participant1 | participant1-displayname | Message 1 | []                | []        |
+
+  Scenario: Retrieve reactions of a message
+    Given user "participant1" creates room "room" (v4)
+      | roomType | 3 |
+      | roomName | room |
+    And user "participant1" adds user "participant2" to room "room" with 200 (v4)
+    And user "participant1" sends message "Message 1" to room "room" with 201
+    And user "participant1" react with "👍" on message "Message 1" to room "room" with 201
+    And user "participant2" react with "👍" on message "Message 1" to room "room" with 201
+    Then user "participant1" retrieve reactions "👍" of message "Message 1" in room "room" with 200
+      | actorType | actorId      | actorDisplayName         | reaction |
+      | users     | participant1 | participant1-displayname | 👍       |
+      | users     | participant2 | participant2-displayname | 👍       |
+    And user "participant2" react with "👎" on message "Message 1" to room "room" with 201
+    And user "participant1" retrieve reactions "👎" of message "Message 1" in room "room" with 200
+      | actorType | actorId      | actorDisplayName         | reaction |
+      | users     | participant2 | participant2-displayname | 👎       |
+    And user "participant1" retrieve reactions "all" of message "Message 1" in room "room" with 200
+      | actorType | actorId      | actorDisplayName         | reaction |
+      | users     | participant1 | participant1-displayname | 👍       |
+      | users     | participant2 | participant2-displayname | 👎       |
+      | users     | participant2 | participant2-displayname | 👍       |
diff --git a/tests/php/CapabilitiesTest.php b/tests/php/CapabilitiesTest.php
index 7edc4f080..a247a18bc 100644
--- a/tests/php/CapabilitiesTest.php
+++ b/tests/php/CapabilitiesTest.php
@@ -26,6 +26,7 @@ declare(strict_types=1);
 namespace OCA\Talk\Tests\Unit;
 
 use OCA\Talk\Capabilities;
+use OCA\Talk\Chat\CommentsManager;
 use OCA\Talk\Config;
 use OCA\Talk\Participant;
 use OCP\Capabilities\IPublicCapability;
@@ -41,6 +42,8 @@ class CapabilitiesTest extends TestCase {
 	protected $serverConfig;
 	/** @var Config|MockObject */
 	protected $talkConfig;
+	/** @var CommentsManager|MockObject */
+	protected $commentsManager;
 	/** @var IUserSession|MockObject */
 	protected $userSession;
 	/** @var array */
@@ -50,7 +53,11 @@ class CapabilitiesTest extends TestCase {
 		parent::setUp();
 		$this->serverConfig = $this->createMock(IConfig::class);
 		$this->talkConfig = $this->createMock(Config::class);
+		$this->commentsManager = $this->createMock(CommentsManager::class);
 		$this->userSession = $this->createMock(IUserSession::class);
+		$this->commentsManager->expects($this->any())
+			->method('supportReactions')
+			->willReturn(true);
 
 		$this->baseFeatures = [
 			'audio',
@@ -96,6 +103,7 @@ class CapabilitiesTest extends TestCase {
 			'direct-mention-flag',
 			'notification-calls',
 			'conversation-permissions',
+			'reactions',
 		];
 	}
 
@@ -103,6 +111,7 @@ class CapabilitiesTest extends TestCase {
 		$capabilities = new Capabilities(
 			$this->serverConfig,
 			$this->talkConfig,
+			$this->commentsManager,
 			$this->userSession
 		);
 
@@ -160,6 +169,7 @@ class CapabilitiesTest extends TestCase {
 		$capabilities = new Capabilities(
 			$this->serverConfig,
 			$this->talkConfig,
+			$this->commentsManager,
 			$this->userSession
 		);
 
@@ -246,6 +256,7 @@ class CapabilitiesTest extends TestCase {
 		$capabilities = new Capabilities(
 			$this->serverConfig,
 			$this->talkConfig,
+			$this->commentsManager,
 			$this->userSession
 		);
 
diff --git a/tests/php/Chat/NotifierTest.php b/tests/php/Chat/NotifierTest.php
index f3fc6df01..2d09b9cb9 100644
--- a/tests/php/Chat/NotifierTest.php
+++ b/tests/php/Chat/NotifierTest.php
@@ -129,20 +129,24 @@ class NotifierTest extends TestCase {
 	/**
 	 * @return Room|MockObject
 	 */
-	private function getRoom() {
+	private function getRoom($settings = []) {
 		/** @var Room|MockObject */
 		$room = $this->createMock(Room::class);
 
 		$room->expects($this->any())
 			->method('getParticipant')
-			->willReturnCallback(function (string $actorId) use ($room): Participant {
+			->willReturnCallback(function (string $actorId) use ($room, $settings): Participant {
 				if ($actorId === 'userNotInOneToOneChat') {
 					throw new ParticipantNotFoundException();
 				}
-				$attendee = Attendee::fromRow([
+				$attendeeRow = [
 					'actor_type' => 'user',
 					'actor_id' => $actorId,
-				]);
+				];
+				if (isset($settings['attendee'][$actorId])) {
+					$attendeeRow = array_merge($attendeeRow, $settings['attendee'][$actorId]);
+				}
+				$attendee = Attendee::fromRow($attendeeRow);
 				return new Participant($room, $attendee, null);
 			});
 
@@ -374,6 +378,44 @@ class NotifierTest extends TestCase {
 	}
 
 	/**
+	 * @dataProvider dataNotifyReacted
+	 */
+	public function testNotifyReacted(int $notify, int $notifyType, int $roomType, string $authorId): void {
+		$this->notificationManager->expects($this->exactly($notify))
+			->method('notify');
+
+		$room = $this->getRoom([
+			'attendee' => [
+				'testUser' => [
+					'notificationLevel' => $notifyType,
+				]
+			]
+		]);
+		$room->method('getType')
+			->willReturn($roomType);
+		$comment = $this->newComment('108', 'users', 'testUser', new \DateTime('@' . 1000000016), 'message');
+		$reaction = $this->newComment('108', 'users', $authorId, new \DateTime('@' . 1000000016), 'message');
+
+		$notifier = $this->getNotifier([]);
+		$notifier->notifyReacted($room, $comment, $reaction);
+	}
+
+	public function dataNotifyReacted(): array {
+		return [
+			'author react to own message' =>
+				[0, Participant::NOTIFY_MENTION, Room::TYPE_GROUP, 'testUser'],
+			'notify never' =>
+				[0, Participant::NOTIFY_NEVER, Room::TYPE_GROUP, 'testUser2'],
+			'notify default, not one to one' =>
+				[0, Participant::NOTIFY_DEFAULT, Room::TYPE_GROUP, 'testUser2'],
+			'notify default, one to one' =>
+				[1, Participant::NOTIFY_DEFAULT, Room::TYPE_ONE_TO_ONE, 'testUser2'],
+			'notify always' =>
+				[1, Participant::NOTIFY_ALWAYS, Room::TYPE_GROUP, 'testUser2'],
+		];
+	}
+
+	/**
 	 * @dataProvider dataGetMentionedUsers
 	 */
 	public function testGetMentionedUsers(string $message, array $expectedReturn): void {