Check-out page login form validation issue

	function after_login($success){
		$user = JFactory::getUser();
		$status = true;
		$app = JFactory::getApplication();
		$user_id=$app->getUserState( HIKASHOP_COMPONENT.'.user_id' );
		global $messDisplay;
		if(is_null($messDisplay)) $messDisplay = 0;
		else $messDisplay = 1;
		if(!$this->cart_update && $user->guest && empty($user_id)){
			JPluginHelper::importPlugin('user');
			$register=JRequest::getString('register','');
			$action = JRequest::getString('login_view_action','');
			if($action=='register' || ($action!='login' && !empty($register))){
				$status = $this->_doRegister();
			}else{
				$login=JRequest::getString('login','');
				if($action=='login' || !empty($login)){
					$status = $this->_doLogin();
				}else{
					$name = @$_REQUEST['data']['register']['email'];
					$username = JRequest::getVar('username', '', 'request', 'username');
					if(!empty($name)){
						$status = $this->_doRegister();
					}elseif(!empty($username)){
						$status = $this->_doLogin();
					}elseif(empty($name) && empty($username) && $messDisplay == 0){
						$app->enqueueMessage('PLEASE_FILL_LOGIN_FIELDS');
					}
				}
			}
			if($status){
				if($this->_getStep('address',$this->previous)!==false || $this->_getStep('confirm',(int)$this->previous)===(int)$this->previous){
					$status = false;
				}
				//try to auto select the address. If the address was selected and that the address is on the same step as the login, stay on the same page
				if(!$this->before_address()){
					$status = false;
				}
				//try to auto select the shipping if the shipping view is not on the same step or if the address has been auto selected
				if(!$status || $this->_getStep('shipping', $this->previous) !== false) {
					$this->before_shipping();
				}
				$this->before_login();
			}
		}
		return $status;
	}