/**
  * Process the payment
  **/
 function process_payment($order_id)
 {
     if (!$this->check_pass) {
         $this->posted_payment_type = null != WC_iPay88::get_post('ipay88_payment_type') ? WC_iPay88::get_post('ipay88_payment_type') : '0';
         $this->check_payment_fields($this->posted_payment_type);
     }
     if (!WC_Compat_iPay88::wc_notice_count('error')) {
         $order = new WC_Order($order_id);
         return array('result' => 'success', 'redirect' => add_query_arg('ptype', $this->posted_payment_type, $order->get_checkout_payment_url(true)));
     }
 }