<?php
/**
 * Magento
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Open Software License (OSL 3.0)
 * that is bundled with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://opensource.org/licenses/osl-3.0.php
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@magentocommerce.com so we can send you a copy immediately.
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade Magento to newer
 * versions in the future. If you wish to customize Magento for your
 * needs please refer to http://www.magentocommerce.com for more information.
 *
 * @category    Mage
 * @package     Mage_Checkout
 * @copyright   Copyright (c) 2012 Magento Inc. (http://www.magentocommerce.com)
 * @license     http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
 */

/**
 * Cart crosssell list
 *
 * @category   Mage
 * @package    Mage_Checkout
 * @author      Magento Core Team <core@magentocommerce.com>
 */
class Mage_Checkout_Block_Cart_Crosssell extends Mage_Catalog_Block_Product_Abstract
{
    /**
     * Items quantity will be capped to this value
     *
     * @var int
     */
    protected $_maxItemCount = 4;

    /**
     * Get crosssell items
     *
     * @return array
     */
    public function getItems()
    {
        $items = $this->getData('items');
        if (is_null($items)) {
            $items = array();
            $ninProductIds = $this->_getCartProductIds();
            if ($ninProductIds) {
                $lastAdded = (int) $this->_getLastAddedProductId();
                if ($lastAdded) {
                    $collection = $this->_getCollection()
                        ->addProductFilter($lastAdded);
                    if (!empty($ninProductIds)) {
                        $collection->addExcludeProductFilter($ninProductIds);
                    }
                    $collection->setPositionOrder()->load();

                    foreach ($collection as $item) {
                        $ninProductIds[] = $item->getId();
                        $items[] = $item;
                    }
                }

                if (count($items) < $this->_maxItemCount) {
                    $filterProductIds = array_merge($this->_getCartProductIds(), $this->_getCartProductIdsRel());
                    $collection = $this->_getCollection()
                        ->addProductFilter($filterProductIds)
                        ->addExcludeProductFilter($ninProductIds)
                        ->setPageSize($this->_maxItemCount-count($items))
                        ->setGroupBy()
                        ->setPositionOrder()
                        ->load();
                    foreach ($collection as $item) {
                        $items[] = $item;
                    }
                }
                
            }

            $this->setData('items', $items);
        }
        return $items;
    }

    /**
     * Count items
     *
     * @return int
     */
    public function getItemCount()
    {
        return count($this->getItems());
    }

    /**
     * Get ids of products that are in cart
     *
     * @return array
     */
    protected function _getCartProductIds()
    {
        $ids = $this->getData('_cart_product_ids');
        if (is_null($ids)) {
            $ids = array();
            foreach ($this->getQuote()->getAllItems() as $item) {
                if ($product = $item->getProduct()) {
                    $ids[] = $product->getId();
                }
            }
            $this->setData('_cart_product_ids', $ids);
        }
        return $ids;
    }

    /**
     * Retrieve Array of product ids which have special relation with products in Cart
     * For example simple product as part of Grouped product
     *
     * @return array
     */
    protected function _getCartProductIdsRel()
    {
        $productIds = array();
        foreach ($this->getQuote()->getAllItems() as $quoteItem) {
            $productTypeOpt = $quoteItem->getOptionByCode('product_type');
            if ($productTypeOpt instanceof Mage_Sales_Model_Quote_Item_Option
                && $productTypeOpt->getValue() == Mage_Catalog_Model_Product_Type_Grouped::TYPE_CODE
                && $productTypeOpt->getProductId()
            ) {
                $productIds[] = $productTypeOpt->getProductId();
            }
        }

        return $productIds;
    }

    /**
     * Get last product ID that was added to cart and remove this information from session
     *
     * @return int
     */
    protected function _getLastAddedProductId()
    {
        return Mage::getSingleton('checkout/session')->getLastAddedProductId(true);
    }

    /**
     * Get quote instance
     *
     * @return Mage_Sales_Model_Quote
     */
    public function getQuote()
    {
        return Mage::getSingleton('checkout/session')->getQuote();
    }

    /**
     * Get crosssell products collection
     *
     * @return Mage_Catalog_Model_Resource_Eav_Mysql4_Product_Link_Product_Collection
     */
    protected function _getCollection()
    {
        $collection = Mage::getModel('catalog/product_link')->useCrossSellLinks()
            ->getProductCollection()
            ->setStoreId(Mage::app()->getStore()->getId())
            ->addStoreFilter()
            ->setPageSize($this->_maxItemCount);
        $this->_addProductAttributesAndPrices($collection);

        Mage::getSingleton('catalog/product_status')->addSaleableFilterToCollection($collection);
        Mage::getSingleton('catalog/product_visibility')->addVisibleInCatalogFilterToCollection($collection);
        Mage::getSingleton('cataloginventory/stock')->addInStockFilterToCollection($collection);

        return $collection;
    }
}
