/src/AppBundle/Service/OAuth/FacebookService.php

<?php

namespace AppBundle\Service\OAuth;

use AppBundle\Entity\User;
use Doctrine\ORM\EntityManager;
use Facebook\Exceptions\FacebookSDKException;
use Facebook\Facebook;
use Facebook\GraphNodes\GraphUser;
use OAuth2\OAuth2;
use OAuth2\OAuth2ServerException;

/**
 * Class FacebookService.
 */
class FacebookService
{
    /**
     * @var EntityManager
     */
    private $em;

    /**
     * @var Facebook
     */
    private $facebook;

    /**
     * @param string $accessToken
     *
     * @throws OAuth2ServerException
     * @throws FacebookSDKException
     *
     * @return \Facebook\GraphNodes\GraphUser
     */
    public function getUserProfile($accessToken)
    {
        try {
            $response = $this->getFacebook()->get('/me?fields=id,name,first_name,last_name', $accessToken);
        } catch (\Exception $e) {
            throw new OAuth2ServerException(OAuth2::HTTP_UNAUTHORIZED, OAuth2::ERROR_INVALID_REQUEST, sprintf('Error Graph API (%s)', $e->getMessage()));
        }

        return $response->getGraphUser();
    }

    /**
     * @param string $facebookId
     *
     * @return User|null
     */
    public function getUserFromGraph($facebookId)
    {
        $user = $this->getEm()->getRepository(User::class)->findOneBy(['facebookId' => $facebookId]);

        return $user;
    }

    /**
     * @param GraphUser $graphUser
     * @param string    $userEmail
     *
     * @return User
     */
    public function createUserFromGraph(GraphUser $graphUser, $userEmail)
    {
        $user = new User();
        $user->setFacebookId($graphUser->getId());
        $user->setProvider(User::PROVIDER_FACEBOOK);
        $user->setPlainPassword(uniqid(md5($graphUser->getId())));
        $user->setRoles(['ROLE_USER']);
        $user->setFirstName($graphUser->getFirstName());
        $user->setLastName($graphUser->getLastName());
        $user->setEmail($userEmail);
        $user->setEnabled(true);

        return $user;
    }

    /**
     * @return EntityManager
     */
    public function getEm(): EntityManager
    {
        return $this->em;
    }

    /**
     * @param EntityManager $em
     */
    public function setEm(EntityManager $em)
    {
        $this->em = $em;
    }

    /**
     * @return Facebook
     */
    public function getFacebook(): Facebook
    {
        return $this->facebook;
    }

    /**
     * @param Facebook $facebook
     */
    public function setFacebook(Facebook $facebook)
    {
        $this->facebook = $facebook;
    }
}