<?php

namespace App\State;

use ApiPlatform\Metadata\Operation;
use ApiPlatform\State\ProcessorInterface;
use App\Entity\Forum;
use Doctrine\ORM\EntityManagerInterface;
use Symfony\Component\DependencyInjection\Attribute\Autowire;

class ForumPositionProcessor implements ProcessorInterface
{
    public function __construct(
        private EntityManagerInterface $entityManager,
        #[Autowire(service: 'api_platform.doctrine.orm.state.persist_processor')]
        private ProcessorInterface $persistProcessor
    ) {
    }

    public function process(mixed $data, Operation $operation, array $uriVariables = [], array $context = []): mixed
    {
        if (!$data instanceof Forum) {
            return $this->persistProcessor->process($data, $operation, $uriVariables, $context);
        }

        $previous = $context['previous_data'] ?? null;
        $parentChanged = $previous instanceof Forum && $previous->getParent()?->getId() !== $data->getParent()?->getId();

        if ($data->getPosition() === 0 || $parentChanged) {
            $qb = $this->entityManager->createQueryBuilder();
            $qb->select('COALESCE(MAX(f.position), 0)')
                ->from(Forum::class, 'f');

            if ($data->getParent()) {
                $qb->andWhere('f.parent = :parent')
                    ->setParameter('parent', $data->getParent());
            } else {
                $qb->andWhere('f.parent IS NULL');
            }

            $maxPosition = (int) $qb->getQuery()->getSingleScalarResult();
            $data->setPosition($maxPosition + 1);
        }

        return $this->persistProcessor->process($data, $operation, $uriVariables, $context);
    }
}