PushService::getRecipient

private function getRecipient(ReactionItem $reaction): array
{
	$userIds = [];
	$relations = Chat::getInstance($reaction->getChatId())->getRelations();

	foreach ($relations as $relation)
	{
		if ($relation->getStartId() <= $reaction->getMessageId())
		{
			$userIds[] = $relation->getUserId();
		}
	}

	return $userIds;
}