class ContactPageAccess

class ContactPageAccess implements AccessInterface {
    
    /**
     * The contact settings config object.
     *
     * @var \Drupal\Core\Config\ConfigFactoryInterface
     */
    protected $configFactory;
    
    /**
     * The user data service.
     *
     * @var \Drupal\user\UserDataInterface
     */
    protected $userData;
    
    /**
     * Constructs a ContactPageAccess instance.
     *
     * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
     *   The config factory.
     * @param \Drupal\user\UserDataInterface $user_data
     *   The user data service.
     */
    public function __construct(ConfigFactoryInterface $config_factory, UserDataInterface $user_data) {
        $this->configFactory = $config_factory;
        $this->userData = $user_data;
    }
    
    /**
     * Checks access to the given user's contact page.
     *
     * @param \Drupal\user\UserInterface $user
     *   The user being contacted.
     * @param \Drupal\Core\Session\AccountInterface $account
     *   The currently logged in account.
     *
     * @return \Drupal\Core\Access\AccessResultInterface
     *   The access result.
     */
    public function access(UserInterface $user, AccountInterface $account) {
        $contact_account = $user;
        // Anonymous users cannot have contact forms.
        if ($contact_account->isAnonymous()) {
            return AccessResult::forbidden();
        }
        // Users may not contact themselves by default, hence this requires user
        // granularity for caching.
        $access = AccessResult::neutral()->cachePerUser();
        if ($account->id() == $contact_account->id()) {
            return $access;
        }
        // User administrators should always have access to personal contact forms.
        $permission_access = AccessResult::allowedIfHasPermission($account, 'administer users');
        if ($permission_access->isAllowed()) {
            return $access->orIf($permission_access);
        }
        // If requested user has been blocked, do not allow users to contact them.
        $access->addCacheableDependency($contact_account);
        if ($contact_account->isBlocked()) {
            return $access;
        }
        // Forbid access if the requested user has disabled their contact form.
        $account_data = $this->userData
            ->get('contact', $contact_account->id(), 'enabled');
        if (isset($account_data) && !$account_data) {
            return $access;
        }
        // If the requested user did not save a preference yet, deny access if the
        // configured default is disabled.
        $contact_settings = $this->configFactory
            ->get('contact.settings');
        $access->addCacheableDependency($contact_settings);
        if (!isset($account_data) && !$contact_settings->get('user_default_enabled')) {
            return $access;
        }
        return $access->orIf(AccessResult::allowedIfHasPermission($account, 'access user contact forms'));
    }

}