class AccountProxy

class AccountProxy implements AccountProxyInterface {
    use DependencySerializationTrait;
    
    /**
     * The instantiated account.
     *
     * @var \Drupal\Core\Session\AccountInterface
     */
    protected $account;
    
    /**
     * Account id.
     *
     * @var int
     */
    protected $id = 0;
    
    /**
     * Event dispatcher.
     *
     * @var \Symfony\Contracts\EventDispatcher\EventDispatcherInterface
     */
    protected $eventDispatcher;
    
    /**
     * AccountProxy constructor.
     *
     * @param \Symfony\Contracts\EventDispatcher\EventDispatcherInterface $eventDispatcher
     *   Event dispatcher.
     */
    public function __construct(EventDispatcherInterface $eventDispatcher) {
        $this->eventDispatcher = $eventDispatcher;
    }
    
    /**
     * {@inheritdoc}
     */
    public function setAccount(AccountInterface $account) {
        // If the passed account is already proxied, use the actual account instead
        // to prevent loops.
        if ($account instanceof static) {
            $account = $account->getAccount();
        }
        $this->account = $account;
        $this->id = $account->id();
        $this->eventDispatcher
            ->dispatch(new AccountSetEvent($account), AccountEvents::SET_USER);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getAccount() {
        if (!isset($this->account)) {
            if ($this->id) {
                // After the container is rebuilt, DrupalKernel sets the initial
                // account to the id of the logged in user. This is necessary in order
                // to refresh the user account reference here.
                $this->setAccount($this->loadUserEntity($this->id));
            }
            else {
                $this->account = new AnonymousUserSession();
            }
        }
        return $this->account;
    }
    
    /**
     * {@inheritdoc}
     */
    public function id() {
        return $this->id;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getRoles($exclude_locked_roles = FALSE) {
        return $this->getAccount()
            ->getRoles($exclude_locked_roles);
    }
    
    /**
     * {@inheritdoc}
     */
    public function hasPermission($permission) {
        return $this->getAccount()
            ->hasPermission($permission);
    }
    
    /**
     * {@inheritdoc}
     */
    public function isAuthenticated() {
        return $this->getAccount()
            ->isAuthenticated();
    }
    
    /**
     * {@inheritdoc}
     */
    public function isAnonymous() {
        return $this->getAccount()
            ->isAnonymous();
    }
    
    /**
     * {@inheritdoc}
     */
    public function getPreferredLangcode($fallback_to_default = TRUE) {
        return $this->getAccount()
            ->getPreferredLangcode($fallback_to_default);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getPreferredAdminLangcode($fallback_to_default = TRUE) {
        return $this->getAccount()
            ->getPreferredAdminLangcode($fallback_to_default);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getAccountName() {
        return $this->getAccount()
            ->getAccountName();
    }
    
    /**
     * {@inheritdoc}
     */
    public function getDisplayName() {
        return $this->getAccount()
            ->getDisplayName();
    }
    
    /**
     * {@inheritdoc}
     */
    public function getEmail() {
        return $this->getAccount()
            ->getEmail();
    }
    
    /**
     * {@inheritdoc}
     */
    public function getTimeZone() {
        return $this->getAccount()
            ->getTimeZone();
    }
    
    /**
     * {@inheritdoc}
     */
    public function getLastAccessedTime() {
        return $this->getAccount()
            ->getLastAccessedTime();
    }
    
    /**
     * {@inheritdoc}
     */
    public function setInitialAccountId($account_id) {
        if (isset($this->account)) {
            throw new \LogicException('AccountProxyInterface::setInitialAccountId() cannot be called after an account was set on the AccountProxy');
        }
        $this->id = $account_id;
    }
    
    /**
     * Load a user entity.
     *
     * The entity type manager requires additional initialization code and cache
     * clearing after the list of modules is changed. Therefore it is necessary to
     * retrieve it as late as possible.
     *
     * Because of serialization issues it is currently not possible to inject the
     * container into the AccountProxy. Thus it is necessary to retrieve the
     * entity type manager statically.
     *
     * @see https://www.drupal.org/node/2430447
     *
     * @param int $account_id
     *   The id of an account to load.
     *
     * @return \Drupal\Core\Session\AccountInterface|null
     *   An account or NULL if none is found.
     */
    protected function loadUserEntity($account_id) {
        return \Drupal::entityTypeManager()->getStorage('user')
            ->load($account_id);
    }

}