Neos: Adjust Reference Selector Starting Point

StartingPointAspect.php

<?php
namespace Your\Vendor\Aop\Aspect;

/*
 *  (c) 2018 punkt.de GmbH - Karlsruhe, Germany - http://punkt.de
 *  All rights reserved.
 */

use Neos\ContentRepository\Domain\Model\NodeInterface;
use Neos\ContentRepository\Domain\Model\NodeType;
use Neos\ContentRepository\Domain\Service\NodeTypeManager;
use Neos\Flow\Annotations as Flow;
use Neos\Flow\Aop\JoinPointInterface;
use Neos\Flow\ObjectManagement\Exception\UnknownObjectException;

/**
 * @Flow\Aspect
 */
class CompanyStartingPointAspect
{
    
    /**
     * @Flow\Inject
     * @var NodeTypeManager
     */
    protected $nodeTypeManager;

    /**
     * @param JoinPointInterface $joinPoint
     * @throws CompanyInformationRetrievalException
     * @throws QueryBuildingException
     * @throws UnknownObjectException
     * @Flow\Around("method(Neos\Neos\Controller\Service\NodesController->indexAction($searchTerm, $nodeIdentifiers, $workspaceName, $dimensions, $nodeTypes, $contextNode))")
     */
    public function setAutomaticStartingPoint(JoinPointInterface $joinPoint)
    {
        $isCategoryNodeType = false;
        foreach ($joinPoint->getMethodArgument('nodeTypes') as $nodeTypeName) {
            $isCategoryNodeType = $this->nodeTypeManager->getNodeType($nodeTypeName)->isOfType('YourVendor.Base:Mixin.Category') || $isCategoryNodeType;
        }

        if($isCategoryNodeType === true) {

            $contextNode = // YOUR CALCULATION HERE;

            $joinPoint->setMethodArgument('contextNode', $contextNode);
        }

        $joinPoint->getAdviceChain()->proceed($joinPoint);
    }
}