Backend\Core\Engine\DataGridFunctions::getLongDate PHP Method

    public static function getLongDate($timestamp)
    {
        $timestamp = (int) $timestamp;
        // if invalid timestamp return an empty string
        if ($timestamp <= 0) {
            return '';
        }
        // get user setting for long dates
        $format = Authentication::getUser()->getSetting('datetime_format');
        // format the date according the user his settings
        return \SpoonDate::getDate($format, $timestamp, BackendLanguage::getInterfaceLanguage());
    }

    /**
     *
     * Get the mail stats
     *
     * @param $id
     *
     * @return array
     */
    public static function getStatsMail($id)
    {
        $return = (array) BackendModel::getContainer()->get('database')->getRecord('SELECT i.*, UNIX_TIMESTAMP(i.start_time) AS date, COUNT(DISTINCT u.user_id) AS users
														FROM mailengine_stats_mail AS i
															LEFT JOIN mailengine_stats_mail_users AS u ON u.send_id = i.id
														WHERE i.id = ?
														GROUP BY i.id', array((int) $id));
        $returnOpened = (array) BackendModel::getContainer()->get('database')->getRecord('SELECT i.*,  COUNT(DISTINCT o.user_id) AS opened
														FROM mailengine_stats_mail AS i
															LEFT JOIN mailengine_stats_mail_opened AS o ON o.send_id = i.id
														WHERE i.id = ?
														GROUP BY i.id', array((int) $id));
        //--Format date
        $return["date"] = BackendDataGridFunctions::getLongDate($return["date"]);
        $return["percentage"] = BackendTemplateModifiers::formatNumber(round($returnOpened["opened"] / $return['users'] * 100, 0));
        return $return;
    }