Chat::getAction

public function getAction(int $entityId, int $entityTypeId) : ?array
{
	if (!\Bitrix\Main\Loader::includeModule('im'))
	{
		$this->addError(new Error('im module not installed'));

		return null;
	}

	if (!CCrmOwnerType::IsDefined($entityTypeId) || $entityId < 0)
	{
		$this->addError(ErrorCode::getEntityTypeNotSupportedError());

		return null;
	}

	$userPermissions = Container::getInstance()->getUserPermissions();
	if (!$userPermissions->checkReadPermissions($entityTypeId, $entityId))
	{
		$this->addError(ErrorCode::getAccessDeniedError());

		return null;
	}

	$userId = Container::getInstance()->getContext()->getUserId();
	$entityTypeName = CCrmOwnerType::ResolveName($entityTypeId);

	$chatID = Im\Chat::joinChat([
		'ENTITY_TYPE' => $entityTypeName,
		'ENTITY_ID' => $entityId,
		'USER_ID' => $userId,
	]);

	if ($chatID === false)
	{
		$this->addError(new Error(Loc::getMessage('CRM_CONTROLLER_TIMELINE_CHAT_ERROR_AT_JOIN_CHAT')));

		return null;
	}

	return ['chatId' => $chatID];
}