/**
  * add birthdate to params list, if it is available
  *
  * @param Mage_Sales_Model_Quote $quote Quote
  * @return array Either empty or with birthdate
  */
 public function convertBirthdate($quote)
 {
     if (is_null($quote->getCustomerDob())) {
         return array();
     }
     return array('GEBURTSDATUM' => Mage::getModel('core/date')->date('d.m.Y', $quote->getCustomerDob()));
 }

 protected function resetQuote(Mage_Sales_Model_Quote $quote)
 {
     if (!$quote->getData('__applied_rules_reset__')) {
         $quote->setAppliedRuleIds('');
         $quote->setData('__applied_rules_reset__', true);
     }
 }

 /**
  * Check whether method is available
  *
  * @param Mage_Sales_Model_Quote|null $quote
  * @return bool
  */
 public function isAvailable($quote = null)
 {
     /* custom code written to round price here as roundPrice function was changed */
     $_grand_price = Mage::app()->getStore()->roundPrice($quote->getGrandTotal());
     $_grand_price = round($_grand_price, 2);
     return parent::isAvailable($quote) && !empty($quote) && $_grand_price == 0;
 }

 protected function setUp()
 {
     parent::setUp();
     $quote = new Mage_Sales_Model_Quote();
     $quote->load('test01', 'reserved_order_id');
     Mage::getSingleton('Mage_Checkout_Model_Session')->setQuoteId($quote->getId());
 }

 /**
  * Add error message if estimation has error
  *
  * @param Mage_Sales_Model_Quote $quote
  * @return $this
  */
 protected function _addErrorMessage($quote)
 {
     if ($quote->getData('estimate_tax_error')) {
         $this->_getErrorsHelper()->addErrorMessage($quote);
     }
     return $this;
 }

 /**
  * Convert the resource model collection to an array
  *
  * @param Mage_Sales_Model_Quote $quote
  *
  * @return array
  */
 public function prepareCollection(Mage_Sales_Model_Quote $quote)
 {
     // Store current state
     $actionType = $this->getActionType();
     $operation = $this->getOperation();
     // Change state
     $this->setActionType(self::ACTION_TYPE_COLLECTION);
     $this->setOperation(self::OPERATION_RETRIEVE);
     $data = [];
     // Get store
     $store = $quote->getStoreId();
     // Get filter
     $filter = $this->getFilter();
     // Prepare methods
     foreach (Mage::helper('payment')->getStoreMethods($store, $quote) as $method) {
         /** @var $method Mage_Payment_Model_Method_Abstract */
         if ($this->_canUseMethod($method, $quote) && $method->isApplicableToQuote($quote, Mage_Payment_Model_Method_Abstract::CHECK_ZERO_TOTAL)) {
             $method->setInfoInstance($quote->getPayment());
             $data[] = $this->prepareMethod($method, $filter);
         }
     }
     // Restore old state
     $this->setActionType($actionType);
     $this->setOperation($operation);
     // Return prepared outbound data
     return $data;
 }

 public function checkQuoteAmount(Mage_Sales_Model_Quote $quote, $amount)
 {
     if (!$quote->getHasError() && $amount >= self::MAXIMUM_AVAILABLE_NUMBER) {
         $quote->setHasError(true);
         $quote->addMessage($this->__('Some items have quantities exceeding allowed quantities. Please select a lower quantity to checkout.'));
     }
     return $this;
 }

 /**
  * extraxcts the according Barclaycard owner* parameter
  *
  * @param Mage_Sales_Model_Quote               $quote
  * @param Mage_Customer_Model_Address_Abstract $billingAddress
  *
  * @return array
  */
 public function getOwnerParams(Mage_Sales_Model_Quote $quote, Mage_Customer_Model_Address_Abstract $billingAddress)
 {
     $ownerParams = array();
     if ($this->getConfig()->canSubmitExtraParameter($quote->getStoreId())) {
         $ownerParams = array('OWNERADDRESS' => str_replace("\n", ' ', $billingAddress->getStreet(1)), 'OWNERTOWN' => $billingAddress->getCity(), 'OWNERZIP' => $billingAddress->getPostcode(), 'OWNERTELNO' => $billingAddress->getTelephone(), 'OWNERCTY' => $billingAddress->getCountry(), 'ECOM_BILLTO_POSTAL_POSTALCODE' => $billingAddress->getPostcode());
     }
     return $ownerParams;
 }

 /**
  * Validates alias for in quote provided addresses
  * @param Mage_Sales_Model_Quote $quote
  * @param Varien_Object $payment
  * @throws Mage_Core_Exception
  */
 protected function validateAlias($quote, $payment)
 {
     $alias = $payment->getAdditionalInformation('alias');
     if (0 < strlen(trim($alias)) && is_numeric($payment->getAdditionalInformation('cvc')) && false === Mage::helper('ops/alias')->isAliasValidForAddresses($quote->getCustomerId(), $alias, $quote->getBillingAddress(), $quote->getShippingAddress(), $quote->getStoreId())) {
         $this->getOnepage()->getCheckout()->setGotoSection('payment');
         Mage::throwException($this->getHelper()->__('Invalid payment information provided!'));
     }
 }

 /**
  * @api
  *
  * To be used in Form_Block, which has to display all wallet types
  *
  * @param Mage_Sales_Model_Quote $quote
  * @return Payone_Core_Model_Config_Payment_Method_Interface
  */
 public function getAllConfigsByQuote(Mage_Sales_Model_Quote $quote)
 {
     if (empty($this->matchingConfigs)) {
         $configStore = $this->getConfigStore($quote->getStoreId());
         $this->matchingConfigs = $configStore->getPayment()->getMethodsForQuote($this->methodType, $quote);
     }
     return $this->matchingConfigs;
 }

 /**
  * returns the quote currency
  *
  * @param $quote
  *
  * @return string - the quotes currency
  */
 public function getQuoteCurrency(Mage_Sales_Model_Quote $quote)
 {
     if ($quote->hasForcedCurrency()) {
         return $quote->getForcedCurrency()->getCode();
     } else {
         return Mage::app()->getStore($quote->getStoreId())->getBaseCurrencyCode();
     }
 }

 /**
  * Check if quote meets the minimun quantity
  * of total items for a specific customer
  *
  * @todo   Change to more meaningful name
  *
  * @param  Mage_Sales_Model_Quote       $quote
  * @param  Mage_Customer_Model_Customer $customer
  * @return int|false
  */
 public function minimunOrderQty(Mage_Sales_Model_Quote $quote, Mage_Customer_Model_Customer $customer)
 {
     $minQtyForCustomer = $this->getConfigValue($customer->getGroupId());
     if ($quote->getItemsQty() < $minQtyForCustomer && $quote->getItemsQty() !== 0) {
         return $minQtyForCustomer;
     }
     return false;
 }

 /**
  * Update Quote Email Address if is guest and current email address assigned doesn't match new email
  *
  * @param Mage_Sales_Model_Quote $quote
  */
 public function updateQuote(Mage_Sales_Model_Quote $quote)
 {
     $queue = Mage::getModel('bronto_emailcapture/queue');
     $currentEmail = $queue->getCurrentEmail();
     if (is_null($quote->getCustomerId()) && $queue->isValidEmail($currentEmail) && $quote->getCustomerEmail() !== $currentEmail) {
         $quote->setCustomerEmail(Mage::getModel('bronto_emailcapture/queue')->getCurrentEmail())->save();
     }
 }

 /**
  * Makes Quote available for Magento Core classes
  *
  * @param Mage_Sales_Model_Quote $quote
  */
 public function populuateQuote(Mage_Sales_Model_Quote &$quote)
 {
     $quote->save();
     $quote = Mage::getModel('sales/quote')->load($quote->getId());
     Mage::getSingleton('checkout/cart')->setQuote($quote);
     Mage::getSingleton('checkout/session')->setQuoteId($quote->getId());
     Mage::getSingleton('checkout/type_onepage')->setQuote($quote);
 }

 /**
  * Check quote amount
  *
  * @param Mage_Sales_Model_Quote $quote
  * @param decimal $amount
  * @return Mage_Sales_Helper_Data
  */
 public function checkQuoteAmount(Mage_Sales_Model_Quote $quote, $amount)
 {
     if (!$quote->getHasError() && $amount >= self::MAXIMUM_AVAILABLE_NUMBER) {
         $quote->setHasError(true);
         $quote->addMessage($this->__('Items maximum quantity or price do not allow checkout.'));
     }
     return $this;
 }

 /**
  * Returns the current customers email adress.
  * @param Mage_Sales_Model_Quote|Mage_Sales_Model_Order $object
  * @return string the customers email adress
  */
 public function getCustomerEmail($object)
 {
     $email = $object->getCustomerEmail();
     if (empty($email)) {
         $email = $object->getBillingAddress()->getEmail();
     }
     return $email;
 }

 /**
  * check if payment method is cc and zero amount authorization is enabled
  *
  * @param Netresearch_OPS_Model_Payment_Abstract $opsPaymentMethod
  *
  * @return bool
  */
 public function isCCAndZeroAmountAuthAllowed(Netresearch_OPS_Model_Payment_Abstract $opsPaymentMethod, Mage_Sales_Model_Quote $quote)
 {
     $result = false;
     $storeId = $quote->getStoreId();
     if ($quote->getBaseGrandTotal() < 0.01 && $opsPaymentMethod instanceof Netresearch_OPS_Model_Payment_Cc && $opsPaymentMethod->isZeroAmountAuthorizationAllowed($storeId) && 0 < $quote->getItemsCount()) {
         $result = true;
     }
     return $result;
 }

 /**
  * Declare quote model object
  *
  * @param   Mage_Sales_Model_Quote $quote
  * @return  Mage_Sales_Model_Quote_Item
  */
 public function setQuote(Mage_Sales_Model_Quote $quote)
 {
     $this->_quote = $quote;
     if ($this->getHasError()) {
         $quote->setHasError(true);
     }
     $quote->addMessage($this->getQuoteMessage(), $this->getQuoteMessageIndex());
     return $this;
 }

 /**
  * @param Mage_Sales_Model_Quote|null $quote
  * @return bool
  */
 public function isAvailable($quote = null)
 {
     $isAvailable = parent::isAvailable();
     $disableZeroTotal = Mage::getStoreConfig('payment/adyen_hpp/disable_zero_total', $quote->getStoreId());
     if (!is_null($quote) && $quote->getGrandTotal() <= 0 && $disableZeroTotal) {
         return false;
     }
     return $isAvailable;
 }

 /**
  * Get QuoteItem that matches Product.
  * 
  * @param Mage_Sales_Model_Quote $quote
  * @param Mage_Catalog_Model_Product $product
  * @return Mage_Sales_Model_Quote_Item | NULL
  */
 protected function _getItemByProduct(Mage_Sales_Model_Quote $quote, Mage_Catalog_Model_Product $product)
 {
     foreach ($quote->getAllItems() as $item) {
         if ($item->getProduct()->getId() == $product->getId()) {
             return $item;
         }
     }
     return Mage::getModel("sales/quote_item")->setProduct($product)->setQuote($quote);
 }