Calendar::getChatAction

public function getChatAction(int $chatId): ?int
{
	if (!Loader::includeModule('im'))
	{
		$this->errorCollection->setError(
			new Error(
				Loc::getMessage('TASKS_CC_ERROR_INCLUDE_MODULE_ERROR'),
				self::ERROR_COULD_NOT_LOAD_MODULE
			)
		);

		return null;
	}

	$userId = User::getId();

	if ($chatId > 0)
	{
		$chatData = CIMChat::getChatData(['ID' => $chatId]);
		if ($chatData)
		{
			$userIds = $chatData['userInChat'][$chatId];

			if (!in_array($userId, $userIds))
			{
				$chat = new CIMChat(0);
				$chat->addUser($chatId, $userId);
			}
		}
	}

	return $chatId;
}