/**
  * @param Mage_Catalog_Model_Resource_Product_Collection $products
  * @return bool
  */
 protected function _process($products)
 {
     $processor = $this->_htmlProcessor;
     $helper = $this->_getHelper();
     foreach ($products as $product) {
         $product->setData('url', $product->getProductUrl());
     }
     $items = $processor->query($helper->getCssSelector('related_product_link'));
     if (count($items) === 0) {
         return false;
     }
     $positions = array();
     foreach ($items as $i => $item) {
         /** @var $item DOMElement */
         $url = $item->getAttribute('href');
         $product = $products->getItemByColumnValue('url', $url);
         if (!$product) {
             continue;
         }
         if ($helper->isEnabledForProduct($product)) {
             $positions[] = $i;
         }
     }
     $processor->replace($helper->getCssSelector('related_product_price'), $this->_getHelper()->prepareReplacement(), $positions);
 }

 /**
  * Callback method for applying price filter.
  * @param Mage_Catalog_Model_Resource_Product_Collection $_collection
  * @param Mage_Adminhtml_Block_Widget_Grid_Column $_column
  */
 public function _filterPrice($_collection, $_column)
 {
     $_field = $_column->getFilterIndex() ? $_column->getFilterIndex() : $_column->getIndex();
     $_condition = $_column->getFilter()->getCondition();
     if (!$_field || !is_array($_condition)) {
         return;
     }
     if (!array_key_exists('type', $_condition) || !is_numeric($_condition['type'])) {
         $_collection->addFieldToFilter($_field, $_condition);
     } else {
         $_storeId = (int) $this->getRequest()->getParam('store', 0);
         $_store = Mage::app()->getStore($_storeId);
         $_joinCondition = array('`e`.`entity_id` = `at_reservation_price`.`entity_id`', '`at_reservation_price`.`store_id` = ' . $_store->getId(), '`at_reservation_price`.`ptype` = ' . $_condition['type']);
         if (array_key_exists('from', $_condition)) {
             $_joinCondition[] = '`at_reservation_price`.`price` >= ' . $_condition['from'];
         }
         if (array_key_exists('to', $_condition)) {
             $_joinCondition[] = '`at_reservation_price`.`price` <= ' . $_condition['to'];
         }
         $_joinCondition[] = '`at_reservation_price`.`date_from` = \'0000-00-00 00:00:00\' OR DATE(`at_reservation_price`.`date_from`) <= DATE(\'' . date('Y-m-d H:i:s', Mage::getModel('core/date')->gmtTimestamp(time())) . '\')';
         $_joinCondition[] = '`at_reservation_price`.`date_to` = \'0000-00-00 00:00:00\' OR DATE(`at_reservation_price`.`date_to`) >= DATE(\'' . date('Y-m-d H:i:s', Mage::getModel('core/date')->gmtTimestamp(time())) . '\')';
         $_collection->getSelect()->joinInner(array('at_reservation_price' => $_collection->getTable('payperrentals/reservationprices')), '(' . implode(') AND (', $_joinCondition) . ')', array('price_type' => 'at_reservation_price.ptype', 'reservation_price' => 'at_reservation_price.price', 'reservation_number' => 'at_reservation_price.numberof'));
         /** TODO Check collection count calculation with group. I think need change join for use distinct */
         $_collection->getSelect()->group('e.entity_id');
     }
 }

 /**
  * Add only is in stock products filter to product collection
  *
  * @param Mage_Catalog_Model_Resource_Product_Collection $collection
  *
  * @return Mage_CatalogInventory_Model_Resource_Stock_Status
  */
 public function addIsInStockFilterToCollection($collection)
 {
     $websiteId = Mage::app()->getStore($collection->getStoreId())->getWebsiteId();
     $joinCondition = $this->_getReadAdapter()->quoteInto('e.entity_id = status_table_mli.product_id' . ' AND status_table_mli.store_id = ?', Mage::app()->getStore()->getId());
     $collection->getSelect()->join(array('status_table_mli' => $this->getTable('demac_multilocationinventory/stock_status_index')), $joinCondition, array())->where('status_table_mli.is_in_stock=1');
     return $this;
 }

 /**
  * Make collection not to load products that are in specified quote
  *
  * @param Mage_Catalog_Model_Resource_Product_Collection $collection
  * @param int $quoteId
  * @return Mage_Checkout_Model_Resource_Cart
  */
 public function addExcludeProductFilter($collection, $quoteId)
 {
     $adapter = $this->_getReadAdapter();
     $exclusionSelect = $adapter->select()->from($this->getTable('sales/quote_item'), array('product_id'))->where('quote_id = ?', $quoteId);
     $condition = $adapter->prepareSqlCondition('e.entity_id', array('nin' => $exclusionSelect));
     $collection->getSelect()->where($condition);
     return $this;
 }

 /**
  * Add join for catalog in stock field to product collection
  *
  * @param Mage_Catalog_Model_Resource_Product_Collection $productCollection
  * @return Mage_CatalogInventory_Model_Resource_Stock_Item
  */
 public function addCatalogInventoryToProductCollection($productCollection)
 {
     $adapter = $this->_getReadAdapter();
     $isManageStock = (int) Mage::getStoreConfig(Mage_CatalogInventory_Model_Stock_Item::XML_PATH_MANAGE_STOCK);
     $stockExpr = $adapter->getCheckSql('cisi.use_config_manage_stock = 1', $isManageStock, 'cisi.manage_stock');
     $stockExpr = $adapter->getCheckSql("({$stockExpr} = 1)", 'cisi.is_in_stock', '1');
     $productCollection->joinTable(array('cisi' => 'cataloginventory/stock_item'), 'product_id=entity_id', array('is_saleable' => new Zend_Db_Expr($stockExpr), 'inventory_in_stock' => 'is_in_stock'), null, 'left');
     return $this;
 }

 public function addMinimalPrices(Mage_Catalog_Model_Resource_Product_Collection $collection)
 {
     $minimalPrices = $this->_getResource()->getMinimalPrices($collection->getLoadedIds());
     foreach ($minimalPrices as $row) {
         $item = $collection->getItemById($row['entity_id']);
         if ($item) {
             $item->setData('minimal_price', $row['value']);
             $item->setData('minimal_tax_class_id', $row['tax_class_id']);
         }
     }
 }

 /**
  * Add tax class id attribute to select and join price rules data if needed
  *
  * @return Mage_Catalog_Model_Resource_Product_Collection
  */
 protected function _beforeLoad()
 {
     if (isset($this->_productLimitationFilters['category_id']) && is_array($this->_productLimitationFilters['category_id'])) {
         $this->getSelect()->group('e.entity_id');
     }
     return parent::_beforeLoad();
 }

 /**
  * @param Mage_Catalog_Model_Resource_Product_Collection $collection
  * @param string $currDir
  *
  * @return $this
  */
 public function apply($collection, $currDir)
 {
     if (!$this->isEnabled()) {
         return $this;
     }
     $alias = 'price_index';
     if (preg_match('/`([a-z0-9\\_]+)`\\.`final_price`/', $collection->getSelect()->__toString(), $m)) {
         $alias = $m[1];
     }
     $price = Mage::getStoreConfig('amsorting/general/profit_price');
     $attribute = Mage::getStoreConfig('amsorting/general/product_attribute');
     $collection->joinAttribute('cost', Mage_Catalog_Model_Product::ENTITY . '/' . $attribute, 'entity_id', null, 'left', Mage::app()->getStore()->getId());
     $collection->getSelect()->columns(array('profit' => "(`{$alias}`.`{$price}` - IF(`at_cost`.`value` IS NULL, 0, `at_cost`.`value`))"));
     $collection->getSelect()->order("profit {$currDir}");
     return $this;
 }

 /**
  * @param Mage_Catalog_Model_Resource_Product_Collection $productCollection
  * @return mixed
  */
 public function sort(Mage_Catalog_Model_Resource_Product_Collection $productCollection)
 {
     //Pass a small validation
     if (!$this->_getHelper()->isCategorySortingEnable() || $productCollection->getFlag(self::MARKETO_SORTED)) {
         return $productCollection;
     }
     $categoriesList = $this->_getPesonalizeCalculator()->getScoreCategoryParams(HooshMarketing_Marketo_Model_Personalize_Calculator::CATEGORY_ID_AND_SCORE);
     //get List of categories with key -> Category_id and value - Score
     if (!count($categoriesList)) {
         //if we havn`t score categories do nothing
         return $productCollection;
     }
     uasort($categoriesList, function ($f, $s) {
         return $f > $s ? 1 : -1;
         //sort by descending
     });
     //Sort categories in order to show top scored categories first
     $categoriesList = array_keys($categoriesList);
     // get only category ids
     try {
         $productCategoryTable = $this->_getCoreResource()->getTableName("catalog_category_product");
         $productCollection->getSelect()->joinLeft(array("marketo_category_table" => $productCategoryTable), "marketo_category_table.product_id = e.entity_id", array("top_category_id" => "marketo_category_table.category_id"))->group("entity_id")->order("FIELD(top_category_id, " . implode(',', $categoriesList) . ") DESC");
         //order by top
         $productCollection->setFlag(self::MARKETO_SORTED, true);
         //to set order only one time
     } catch (Exception $e) {
         Mage::logException($e);
     }
     return $productCollection;
 }

 /**
  * Apply filter by category id
  *
  * @param Mage_Catalog_Model_Resource_Product_Collection $collection
  */
 protected function _applyCategoryFilter(Mage_Catalog_Model_Resource_Product_Collection $collection)
 {
     $categoryId = $this->getRequest()->getParam('category_id');
     if ($categoryId) {
         $category = $this->_getCategoryById($categoryId);
         if (!$category->getId()) {
             $this->_critical('Category not found.', Mage_Api2_Model_Server::HTTP_BAD_REQUEST);
         }
         $collection->addCategoryFilter($category);
     }
 }

 /**
  * @param Mage_Catalog_Model_Resource_Product_Collection $collection
  * @param string $currDir
  *
  * @return $this
  */
 public function apply($collection, $currDir)
 {
     if (!$this->isEnabled()) {
         return $this;
     }
     $sorters = $this->getSorters();
     if (Mage::getStoreConfig('amsorting/general/use_index')) {
         foreach ($sorters as $sorter) {
             $collection->joinField($sorter->getCode(), $sorter->getIndexTable(), $sorter->getCode(), 'id=entity_id', array('store_id' => Mage::app()->getStore()->getId()), 'left');
         }
     } else {
         $select = $collection->getSelect();
         $col = $select->getPart('columns');
         foreach ($sorters as $sorter) {
             $col[] = array('', $sorter->getColumnSelect(), $sorter->getCode());
         }
         $select->setPart('columns', $col);
     }
     $collection->getSelect()->order(new Zend_Db_Expr('(' . $sorters['dividend']->getCode() . '/' . $sorters['divider']->getCode() . ') ' . $currDir));
     return $this;
 }

 /**
  * Get link collection
  *
  * @return Mage_Catalog_Model_Resource_Product_Collection|null
  */
 public function getLinkCollection()
 {
     if (is_null($this->_linkCollection)) {
         $this->_linkCollection = $this->_getTargetLinkCollection();
         if ($this->_linkCollection) {
             // Perform rotation mode
             $select = $this->_linkCollection->getSelect();
             $rotationMode = $this->getTargetRuleHelper()->getRotationMode($this->getProductListType());
             if ($rotationMode == Enterprise_TargetRule_Model_Rule::ROTATION_SHUFFLE) {
                 Mage::getResourceSingleton('enterprise_targetrule/index')->orderRand($select);
             } else {
                 $select->order('link_attribute_position_int.value ASC');
             }
         }
     }
     return $this->_linkCollection;
 }

 /**
  * Add all attributes and apply pricing logic to products collection
  * to get correct values in different products lists.
  * E.g. crosssells, upsells, new products, recently viewed
  *
  * @param Mage_Catalog_Model_Resource_Product_Collection $collection
  * @return Mage_Catalog_Model_Resource_Product_Collection
  */
 protected function _addProductAttributesAndPrices(Mage_Catalog_Model_Resource_Product_Collection $collection)
 {
     $test = Mage::getSingleton('catalog/config')->getProductAttributes();
     return $collection->addMinimalPrice()->addFinalPrice()->addTaxPercents()->addAttributeToSelect(Mage::getSingleton('catalog/config')->getProductAttributes())->addUrlRewrite();
 }

 /**
  * Add low stock filter to product collection
  *
  * @param Mage_Catalog_Model_Resource_Product_Collection $collection
  * @param array $fields
  * @return Mage_CatalogInventory_Model_Resource_Stock
  */
 public function addLowStockFilter(Mage_Catalog_Model_Resource_Product_Collection $collection, $fields)
 {
     $this->_initConfig();
     $adapter = $collection->getSelect()->getAdapter();
     $qtyIf = $adapter->getCheckSql('invtr.use_config_notify_stock_qty', $this->_configNotifyStockQty, 'invtr.notify_stock_qty');
     $conditions = array(array($adapter->prepareSqlCondition('invtr.use_config_manage_stock', 1), $adapter->prepareSqlCondition($this->_isConfigManageStock, 1), $adapter->prepareSqlCondition('invtr.qty', array('lt' => $qtyIf))), array($adapter->prepareSqlCondition('invtr.use_config_manage_stock', 0), $adapter->prepareSqlCondition('invtr.manage_stock', 1)));
     $where = array();
     foreach ($conditions as $k => $part) {
         $where[$k] = join(' ' . Zend_Db_Select::SQL_AND . ' ', $part);
     }
     $where = $adapter->prepareSqlCondition('invtr.low_stock_date', array('notnull' => true)) . ' ' . Zend_Db_Select::SQL_AND . ' ((' . join(') ' . Zend_Db_Select::SQL_OR . ' (', $where) . '))';
     $collection->joinTable(array('invtr' => 'cataloginventory/stock_item'), 'product_id = entity_id', $fields, $where);
     return $this;
 }

 /**
  * Handles collection filtering by ids retrieves from search engine.
  * Will also stores faceted data and total records.
  *
  * @return Mage_Catalog_Model_Resource_Product_Collection
  */
 protected function _beforeLoad()
 {
     $this->_prepareQuery();
     $ids = array();
     if (!empty($this->_facets)) {
         $this->getSearchEngineQuery()->resetFacets();
     }
     $result = $this->getSearchEngineQuery()->search();
     $ids = isset($result['ids']) ? $result['ids'] : array();
     if (isset($result['facets'])) {
         $this->_facets = array_merge($this->_facets, $result['facets']);
     }
     $this->_totalRecords = isset($result['total_count']) ? $result['total_count'] : null;
     $this->_isSpellChecked = $this->getSearchEngineQuery()->isSpellchecked();
     if (empty($ids)) {
         $ids = array(0);
         // Fix for no result
     }
     $this->addIdFilter($ids);
     $this->_searchedEntityIds = $ids;
     $this->_pageSize = false;
     return parent::_beforeLoad();
 }

 /**
  * @dataProvider setOrderDataProvider
  */
 public function testSetOrder($order, $expectedOrder)
 {
     $this->_collection->setOrder($order);
     $this->_collection->load();
     // perform real SQL query
     $selectOrder = $this->_collection->getSelect()->getPart(Zend_Db_Select::ORDER);
     foreach ($expectedOrder as $field) {
         $orderBy = array_shift($selectOrder);
         $this->assertArrayHasKey(0, $orderBy);
         $this->assertTrue(false !== strpos($orderBy[0], $field), 'Ordering by same column more than once is restricted by multiple RDBMS requirements.');
     }
 }

 /**
  * Added exception handling to addItem, otherwise in some cases will throw an exception
  * 
  * @param \Varien_Object $object
  */
 public function addItem(\Varien_Object $object)
 {
     try {
         return parent::addItem($object);
     } catch (Exception $e) {
     }
 }

 public function addAttributeToSort($attribute, $dir = self::SORT_ORDER_ASC)
 {
     if ($attribute == 'best') {
         $this->getSelect()->order("t2.position " . $dir);
         return $this;
     }
     return parent::addAttributeToSort($attribute, $dir);
 }

 /**
  * Add attribute to sort
  *
  * @param string $attribute
  * @param string $dir
  * @return Mage_Reports_Model_Resource_Review_Product_Collection
  */
 public function addAttributeToSort($attribute, $dir = self::SORT_ORDER_ASC)
 {
     if (in_array($attribute, array('review_cnt', 'last_created', 'avg_rating', 'avg_rating_approved'))) {
         $this->getSelect()->order($attribute . ' ' . $dir);
         return $this;
     }
     return parent::addAttributeToSort($attribute, $dir);
 }

 /**
  * Set Order field
  *
  * @param string $attribute
  * @param string $dir
  * @return Mage_CatalogSearch_Model_Resource_Fulltext_Collection
  */
 public function setOrder($attribute, $dir = 'desc')
 {
     if ($attribute == 'relevance') {
         //$this->getSelect()->order("relevance {$dir}");
     } else {
         parent::setOrder($attribute, $dir);
     }
     return $this;
 }