public function print_login() {
        $url = $this->dropbox->get_login_url();
        if ($this->options['ajax']) {
            $ret = array();
            $btn = new \stdClass();
            $btn->type = 'popup';
            $btn->url = $url->out(false);
            $ret['login'] = array($btn);
            return $ret;
        } else {
            echo html_writer::link($url, get_string('login', 'repository'), array('target' => '_blank'));
        }
    }