<?php

namespace App\EventListener;

use App\Doctrine\Encryption\EncryptingEntityInterface;
use App\Doctrine\Encryption\EncryptorInterface;
use Doctrine\Common\EventSubscriber;
use Doctrine\ORM\Event\LifecycleEventArgs;
use Doctrine\ORM\Event\PreFlushEventArgs;
use Doctrine\ORM\Events;

/**
 * Doctrine event subscriber to encrypt/decrypt entity properties.
 *
 * Inspired from https://github.com/michaeldegroot/DoctrineEncryptBundle
 *
 * Instead of using an annotation, we programmatically encrypted/decrypted field relations.
 */
class DoctrineEncryptListener implements EventSubscriber
{
    /**
     * @var EncryptorInterface
     */
    private $encryptor;

    public function __construct(EncryptorInterface $encryptor)
    {
        $this->encryptor = $encryptor;
    }

    public function getSubscribedEvents(): array
    {
        return [
            Events::postLoad,
            Events::preFlush,
        ];
    }

    /**
     * After loading an entity, populate the decrypted properties by decrypting the encrypted tracked property.
     *
     * Track the entity so that we also update fields in preFlush.
     */
    public function postLoad(LifecycleEventArgs $args): void
    {
        $entity = $args->getEntity();
        if (!$entity instanceof EncryptingEntityInterface) {
            return;
        }

        $entity->decrypt($this->encryptor);
    }

    /**
     * Encrypt properties of entities that are newly inserted into the database or that have previously been loaded from the database.
     */
    public function preFlush(PreFlushEventArgs $preFlushEventArgs): void
    {
        // encrypt entities that we are about to insert
        $unitOfWork = $preFlushEventArgs->getEntityManager()->getUnitOfWork();
        foreach ($unitOfWork->getScheduledEntityInsertions() as $entity) {
            if ($entity instanceof EncryptingEntityInterface) {
                $entity->encrypt($this->encryptor);
            }
        }
    }
}