Only update the last_message and last_activity once

Especially when adding multiple system messages we updated the room
data way too often.

Signed-off-by: Joas Schilling <coding@schilljs.com>

6 files changed, 95 insertions, 13 deletions

diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
index 24075635b..a91636635 100644
--- a/lib/AppInfo/Application.php
+++ b/lib/AppInfo/Application.php
@@ -217,6 +217,10 @@ class Application extends App implements IBootstrap {
 
 	protected function registerRoomActivityHooks(IEventDispatcher $dispatcher): void {
 		$listener = function (ChatEvent $event): void {
+			if ($event->shouldSkipLastActivityUpdate()) {
+				return;
+			}
+
 			$room = $event->getRoom();
 			/** @var ITimeFactory $timeFactory */
 			$timeFactory = $this->getContainer()->query(ITimeFactory::class);
diff --git a/lib/Chat/ChatManager.php b/lib/Chat/ChatManager.php
index 315116835..c50cf7005 100644
--- a/lib/Chat/ChatManager.php
+++ b/lib/Chat/ChatManager.php
@@ -118,6 +118,11 @@ class ChatManager {
 	 * @param bool $sendNotifications
 	 * @param string|null $referenceId
 	 * @param int|null $parentId
+	 * @param bool $shouldSkipLastMessageUpdate If multiple messages will be posted
+	 *             (e.g. when adding multiple users to a room) we can skip the last
+	 *             message and last activity update until the last entry was created
+	 *             and then update with those values.
+	 *             This will replace O(n) with 1 database update.
 	 * @return IComment
 	 */
 	public function addSystemMessage(
@@ -128,7 +133,8 @@ class ChatManager {
 		\DateTime $creationDateTime,
 		bool $sendNotifications,
 		?string $referenceId = null,
-		?int $parentId = null
+		?int $parentId = null,
+		bool $shouldSkipLastMessageUpdate = false
 	): IComment {
 		$comment = $this->commentsManager->create($actorType, $actorId, 'chat', (string) $chat->getId());
 		$comment->setMessage($message, self::MAX_CHAT_LENGTH);
@@ -152,14 +158,16 @@ class ChatManager {
 			$comment->setVerb('system');
 		}
 
-		$event = new ChatEvent($chat, $comment);
+		$event = new ChatEvent($chat, $comment, $shouldSkipLastMessageUpdate);
 		$this->dispatcher->dispatch(self::EVENT_BEFORE_SYSTEM_MESSAGE_SEND, $event);
 		try {
 			$this->commentsManager->save($comment);
 
-			// Update last_message
-			$chat->setLastMessage($comment);
-			$this->unreadCountCache->clear($chat->getId() . '-');
+			if (!$shouldSkipLastMessageUpdate) {
+				// Update last_message
+				$chat->setLastMessage($comment);
+				$this->unreadCountCache->clear($chat->getId() . '-');
+			}
 
 			if ($sendNotifications) {
 				$this->notifier->notifyOtherParticipant($chat, $comment, []);
diff --git a/lib/Chat/SystemMessage/Listener.php b/lib/Chat/SystemMessage/Listener.php
index 0ecbd4636..2308b061b 100644
--- a/lib/Chat/SystemMessage/Listener.php
+++ b/lib/Chat/SystemMessage/Listener.php
@@ -43,6 +43,7 @@ use OCA\Talk\Share\RoomShareProvider;
 use OCA\Talk\TalkSession;
 use OCA\Talk\Webinary;
 use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\Comments\IComment;
 use OCP\EventDispatcher\Event;
 use OCP\EventDispatcher\IEventDispatcher;
 use OCP\EventDispatcher\IEventListener;
@@ -263,7 +264,15 @@ class Listener implements IEventListener {
 					|| $listener->getUserId() !== $participant['actorId']
 					// - has joined a listable room on their own
 					|| $participantType === Participant::USER) {
-					$listener->sendSystemMessage($room, 'user_added', ['user' => $participant['actorId']]);
+					$comment = $listener->sendSystemMessage(
+						$room,
+						'user_added',
+						['user' => $participant['actorId']],
+						null,
+						$event->shouldSkipLastMessageUpdate()
+					);
+
+					$event->setLastMessage($comment);
 				}
 			}
 		});
@@ -379,7 +388,7 @@ class Listener implements IEventListener {
 		}
 	}
 
-	protected function sendSystemMessage(Room $room, string $message, array $parameters = [], Participant $participant = null): void {
+	protected function sendSystemMessage(Room $room, string $message, array $parameters = [], Participant $participant = null, bool $shouldSkipLastMessageUpdate = false): IComment {
 		if ($participant instanceof Participant) {
 			$actorType = $participant->getAttendee()->getActorType();
 			$actorId = $participant->getAttendee()->getActorId();
@@ -408,11 +417,13 @@ class Listener implements IEventListener {
 			$referenceId = (string) $referenceId;
 		}
 
-		$this->chatManager->addSystemMessage(
+		return $this->chatManager->addSystemMessage(
 			$room, $actorType, $actorId,
 			json_encode(['message' => $message, 'parameters' => $parameters]),
 			$this->timeFactory->getDateTime(), $message === 'file_shared',
-			$referenceId
+			$referenceId,
+			null,
+			$shouldSkipLastMessageUpdate
 		);
 	}
 
diff --git a/lib/Events/AddParticipantsEvent.php b/lib/Events/AddParticipantsEvent.php
index 5d214bfb2..f05c02354 100644
--- a/lib/Events/AddParticipantsEvent.php
+++ b/lib/Events/AddParticipantsEvent.php
@@ -24,17 +24,25 @@ declare(strict_types=1);
 namespace OCA\Talk\Events;
 
 use OCA\Talk\Room;
+use OCP\Comments\IComment;
 
 class AddParticipantsEvent extends RoomEvent {
 
 	/** @var array */
 	protected $participants;
 
+	/** @var bool */
+	protected $skipLastMessageUpdate;
+
+	/** @var IComment|null */
+	protected $lastMessage;
 
 	public function __construct(Room $room,
-								array $participants) {
+								array $participants,
+								bool $skipLastMessageUpdate = false) {
 		parent::__construct($room);
 		$this->participants = $participants;
+		$this->skipLastMessageUpdate = $skipLastMessageUpdate;
 	}
 
 	/**
@@ -43,4 +51,16 @@ class AddParticipantsEvent extends RoomEvent {
 	public function getParticipants(): array {
 		return $this->participants;
 	}
+
+	public function shouldSkipLastMessageUpdate(): bool {
+		return $this->skipLastMessageUpdate;
+	}
+
+	public function setLastMessage(IComment $lastMessage): void {
+		$this->lastMessage = $lastMessage;
+	}
+
+	public function getLastMessage(): ?IComment {
+		return $this->lastMessage;
+	}
 }
diff --git a/lib/Events/ChatEvent.php b/lib/Events/ChatEvent.php
index 2a9e548e2..1f552f7d7 100644
--- a/lib/Events/ChatEvent.php
+++ b/lib/Events/ChatEvent.php
@@ -31,13 +31,33 @@ class ChatEvent extends RoomEvent {
 	/** @var IComment */
 	protected $comment;
 
+	/** @var bool */
+	protected $skipLastActivityUpdate;
 
-	public function __construct(Room $room, IComment $comment) {
+	public function __construct(Room $room,
+								IComment $comment,
+								bool $skipLastActivityUpdate = false) {
 		parent::__construct($room);
 		$this->comment = $comment;
+		$this->skipLastActivityUpdate = $skipLastActivityUpdate;
 	}
 
 	public function getComment(): IComment {
 		return $this->comment;
 	}
+
+	/**
+	 * If multiple messages will be posted (e.g. when adding multiple users to a room)
+	 * we can skip the last message and last activity update until the last entry
+	 * was created and then update with those values.
+	 * This will replace O(n) with 1 database update.
+	 *
+	 * A ChatManager::EVENT_AFTER_MULTIPLE_SYSTEM_MESSAGE_SEND will be triggered
+	 * as a final event when all messages have been created.
+	 *
+	 * @return bool
+	 */
+	public function shouldSkipLastActivityUpdate(): bool {
+		return $this->skipLastActivityUpdate;
+	}
 }
diff --git a/lib/Service/ParticipantService.php b/lib/Service/ParticipantService.php
index 960330cee..c02a4910a 100644
--- a/lib/Service/ParticipantService.php
+++ b/lib/Service/ParticipantService.php
@@ -59,6 +59,7 @@ use OCP\Comments\IComment;
 use OCP\DB\Exception;
 use OCP\DB\QueryBuilder\IQueryBuilder;
 use OCP\EventDispatcher\IEventDispatcher;
+use OCP\ICacheFactory;
 use OCP\IConfig;
 use OCP\IDBConnection;
 use OCP\IGroup;
@@ -94,6 +95,8 @@ class ParticipantService {
 	private $notifications;
 	/** @var ITimeFactory */
 	private $timeFactory;
+	/** @var ICacheFactory */
+	private $cacheFactory;
 
 	public function __construct(IConfig $serverConfig,
 								Config $talkConfig,
@@ -107,7 +110,8 @@ class ParticipantService {
 								IGroupManager $groupManager,
 								MembershipService $membershipService,
 								Notifications $notifications,
-								ITimeFactory $timeFactory) {
+								ITimeFactory $timeFactory,
+								ICacheFactory $cacheFactory) {
 		$this->serverConfig = $serverConfig;
 		$this->talkConfig = $talkConfig;
 		$this->attendeeMapper = $attendeeMapper;
@@ -120,6 +124,7 @@ class ParticipantService {
 		$this->groupManager = $groupManager;
 		$this->membershipService = $membershipService;
 		$this->timeFactory = $timeFactory;
+		$this->cacheFactory = $cacheFactory;
 		$this->notifications = $notifications;
 	}
 
@@ -367,7 +372,7 @@ class ParticipantService {
 		if (empty($participants)) {
 			return;
 		}
-		$event = new AddParticipantsEvent($room, $participants);
+		$event = new AddParticipantsEvent($room, $participants, true);
 		$this->dispatcher->dispatch(Room::EVENT_BEFORE_USERS_ADD, $event);
 
 		$lastMessage = 0;
@@ -426,9 +431,23 @@ class ParticipantService {
 			$this->dispatcher->dispatchTyped($attendeeEvent);
 
 			$this->dispatcher->dispatch(Room::EVENT_AFTER_USERS_ADD, $event);
+
+			$lastMessage = $event->getLastMessage();
+			if ($lastMessage instanceof IComment) {
+				$this->updateRoomLastMessage($room, $lastMessage);
+			}
 		}
 	}
 
+	protected function updateRoomLastMessage(Room $room, IComment $message): void {
+		$room->setLastMessage($message);
+		$room->setLastActivity($message->getCreationDateTime());
+		$lastMessageCache = $this->cacheFactory->createDistributed('talk/lastmsgid');
+		$lastMessageCache->remove($room->getToken());
+		$unreadCountCache = $this->cacheFactory->createDistributed('talk/unreadcount');
+		$unreadCountCache->clear($room->getId() . '-');
+	}
+
 	public function getHighestPermissionAttendee(Room $room): ?Attendee {
 		try {
 			$roomOwners = $this->attendeeMapper->getActorsByParticipantTypes($room->getId(), [Participant::OWNER]);