<?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_Tax
 * @copyright   Copyright (c) 2010 Magento Inc. (http://www.magentocommerce.com)
 * @license     http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
 */

/**
 * Calculate items and address amounts including/excluding tax
 */
class Mage_Tax_Model_Sales_Total_Quote_Subtotal extends Mage_Sales_Model_Quote_Address_Total_Abstract
{
    /**
     * Tax calculation model
     *
     * @var Mage_Tax_Model_Calculation
     */
    protected $_calculator = null;

    /**
     * Tax configuration object
     *
     * @var Mage_Tax_Model_Config
     */
    protected $_config = null;
    protected $_helper = null;

    protected $_subtotalInclTax     = 0;
    protected $_baseSubtotalInclTax = 0;
    protected $_subtotal            = 0;
    protected $_baseSubtotal        = 0;

    /**
     * Flag which is initialized when collect method is start.
     * Is used for checking if store tax and customer tax requests are similar
     *
     * @var bool
     */
    protected $_areTaxRequestsSimilar = false;

    /**
     * Request which can be used for tax rate calculation
     *
     * @var Varien_Object
     */
    protected $_storeTaxRequest = null;

    protected $_store;

    protected $_roundingDeltas = array();

    /**
     * Class constructor
     */
    public function __construct()
    {
        $this->setCode('tax_subtotal');
        $this->_helper      = Mage::helper('tax');
        $this->_calculator  = Mage::getSingleton('tax/calculation');
        $this->_config      = Mage::getSingleton('tax/config');
    }

    /**
     * Calculate item price including/excluding tax, row total including/excluding tax
     * and subotal including/excluding tax.
     * Determine discount price if needed
     *
     * @param   Mage_Sales_Model_Quote_Address $address
     * @return  Mage_Tax_Model_Sales_Total_Quote_Subtotal
     */
    public function collect(Mage_Sales_Model_Quote_Address $address)
    {
        $this->_store   = $address->getQuote()->getStore();
        $this->_address = $address;

        $this->_subtotalInclTax     = 0;
        $this->_baseSubtotalInclTax = 0;
        $this->_subtotal            = 0;
        $this->_baseSubtotal        = 0;
        $this->_roundingDeltas      = array();

        $address->setSubtotalInclTax(0);
        $address->setBaseSubtotalInclTax(0);
        $address->setTotalAmount('subtotal', 0);
        $address->setBaseTotalAmount('subtotal', 0);

        $items = $this->_getAddressItems($address);
        if (!$items) {
            return $this;
        }

        $addressRequest = $this->_getAddressTaxRequest($address);
        $storeRequest   = $this->_getStoreTaxRequest($address);
        $this->_calculator->setCustomer($address->getQuote()->getCustomer());
        if ($this->_config->priceIncludesTax($this->_store)) {
            $classIds = array();
            foreach ($items as $item) {
                $classIds[] = $item->getProduct()->getTaxClassId();
                if ($item->getHasChildren()) {
                    foreach ($item->getChildren() as $child) {
                        $classIds[] = $child->getProduct()->getTaxClassId();
                    }
                }
            }
            $classIds = array_unique($classIds);
            $storeRequest->setProductClassId($classIds);
            $addressRequest->setProductClassId($classIds);
            $this->_areTaxRequestsSimilar = $this->_calculator->compareRequests($storeRequest, $addressRequest);
        }

        foreach ($items as $item) {
            if ($item->getParentItemId()) {
                continue;
            }
            if ($item->getHasChildren() && $item->isChildrenCalculated()) {
                foreach ($item->getChildren() as $child) {
                    $this->_processItem($child, $addressRequest);
                }
                $this->_recalculateParent($item);
            } else {
                $this->_processItem($item, $addressRequest);
            }
            $this->_addSubtotalAmount($address, $item);
        }
        $address->setRoundingDeltas($this->_roundingDeltas);
        return $this;
    }

    /**
     * Caclulate item price and row total with configured rounding level
     *
     * @param Mage_Sales_Model_Quote_Address $address
     * @param Mage_Sales_Model_Quote_Item_Abstract $item
     * @return Mage_Tax_Model_Sales_Total_Quote_Subtotal
     */
    protected function _processItem($item, $taxRequest)
    {
        switch ($this->_config->getAlgorithm($this->_store)) {
            case Mage_Tax_Model_Calculation::CALC_UNIT_BASE:
                $this->_unitBaseCalculation($item, $taxRequest);
                break;
            case Mage_Tax_Model_Calculation::CALC_ROW_BASE:
                $this->_rowBaseCalculation($item, $taxRequest);
                break;
            case Mage_Tax_Model_Calculation::CALC_TOTAL_BASE:
                $this->_totalBaseCalculation($item, $taxRequest);
                break;
            default:
                break;
        }
        return $this;
    }

    /**
     * Calculate item price and row total including/excluding tax based on unit price rounding level
     *
     * @param Mage_Sales_Model_Quote_Item_Abstract $item
     * @param Varien_Object $request
     * @return Mage_Tax_Model_Sales_Total_Quote_Subtotal
     */
    protected function _unitBaseCalculation($item, $request)
    {
        $rate   = $this->_calculator->getRate($request->setProductClassId($item->getProduct()->getTaxClassId()));
        $qty    = $item->getTotalQty();

        $price          = $taxPrice         = $item->getCalculationPrice();
        $basePrice      = $baseTaxPrice     = $item->getBaseCalculationPrice();
        $subtotal       = $taxSubtotal      = $item->getRowTotal();
        $baseSubtotal   = $baseTaxSubtotal  = $item->getBaseRowTotal();
        $taxOnOrigPrice = !$this->_helper->applyTaxOnCustomPrice($this->_store) && $item->hasCustomPrice();
        if ($taxOnOrigPrice) {
            $origPrice       = $item->getOriginalPrice();
            $baseOrigPrice   = $item->getBaseOriginalPrice();
        }


        $item->setTaxPercent($rate);
        if ($this->_config->priceIncludesTax($this->_store)) {
            if ($this->_areTaxRequestsSimilar) {
                $tax            = $this->_calculator->calcTaxAmount($price, $rate, true);
                $baseTax        = $this->_calculator->calcTaxAmount($basePrice, $rate, true);
                $taxPrice       = $price;
                $baseTaxPrice   = $basePrice;
                $taxSubtotal    = $subtotal;
                $baseTaxSubtotal= $baseSubtotal;
                $price          = $price - $tax;
                $basePrice      = $basePrice - $baseTax;
                $subtotal       = $price * $qty;
                $baseSubtotal   = $basePrice * $qty;
                if ($taxOnOrigPrice) {
                    $taxable        = $origPrice;
                    $baseTaxable    = $baseOrigPrice;
                } else {
                    $taxable        = $taxPrice;
                    $baseTaxable    = $baseTaxPrice;
                }
                $isPriceInclTax = true;
            } else {
                $storeRate      = $this->_calculator->getStoreRate($request, $this->_store);
                $storeTax       = $this->_calculator->calcTaxAmount($price, $storeRate, true);
                $baseStoreTax   = $this->_calculator->calcTaxAmount($basePrice, $storeRate, true);
                $price          = $price - $storeTax;
                $basePrice      = $basePrice - $baseStoreTax;
                $subtotal       = $price * $qty;
                $baseSubtotal   = $basePrice * $qty;

                $tax            = $this->_calculator->calcTaxAmount($price, $rate, false);
                $baseTax        = $this->_calculator->calcTaxAmount($basePrice, $rate, false);
                $taxPrice       = $price + $tax;
                $baseTaxPrice   = $basePrice + $baseTax;
                $taxSubtotal    = $taxPrice * $qty;
                $baseTaxSubtotal= $baseTaxPrice * $qty;
                if ($taxOnOrigPrice) {
                    $taxable        = $origPrice - $storeTax;
                    $baseTaxable    = $baseOrigPrice - $baseStoreTax;
                } else {
                    $taxable        = $price;
                    $baseTaxable    = $basePrice;
                }
                $isPriceInclTax = false;
            }
        } else {
            $tax            = $this->_calculator->calcTaxAmount($price, $rate, false);
            $baseTax        = $this->_calculator->calcTaxAmount($basePrice, $rate, false);
            $taxPrice       = $price + $tax;
            $baseTaxPrice   = $basePrice + $baseTax;
            $taxSubtotal    = $taxPrice * $qty;
            $baseTaxSubtotal= $baseTaxPrice * $qty;
            if ($taxOnOrigPrice) {
                $taxable        = $origPrice;
                $baseTaxable    = $baseOrigPrice;
            } else {
                $taxable        = $price;
                $baseTaxable    = $basePrice;
            }
            $isPriceInclTax = false;
        }

        if ($item->hasCustomPrice()) {
            $item->setCustomPrice($price);
            $item->setBaseCustomPrice($basePrice);
        } else {
            $item->setOriginalPrice($price);
        }
        $item->setPrice($basePrice);
        $item->setBasePrice($basePrice);
        $item->setRowTotal($subtotal);
        $item->setBaseRowTotal($baseSubtotal);
        $item->setPriceInclTax($taxPrice);
        $item->setBasePriceInclTax($baseTaxPrice);
        $item->setRowTotalInclTax($taxSubtotal);
        $item->setBaseRowTotalInclTax($baseTaxSubtotal);
        $item->setTaxableAmount($taxable);
        $item->setBaseTaxableAmount($baseTaxable);
        $item->setIsPriceInclTax($isPriceInclTax);
        if ($this->_config->discountTax($this->_store)) {
            $item->setDiscountCalculationPrice($taxPrice);
            $item->setBaseDiscountCalculationPrice($baseTaxPrice);
        }
        return $this;
    }

    /**
     * Calculate item price and row total including/excluding tax based on row total price rounding level
     *
     * @param Mage_Sales_Model_Quote_Item_Abstract $item
     * @param Varien_Object $request
     * @return Mage_Tax_Model_Sales_Total_Quote_Subtotal
     */
    protected function _rowBaseCalculation($item, $request)
    {
        $rate   = $this->_calculator->getRate($request->setProductClassId($item->getProduct()->getTaxClassId()));
        $qty    = $item->getTotalQty();

        $price          = $taxPrice         = $item->getCalculationPrice();
        $basePrice      = $baseTaxPrice     = $item->getBaseCalculationPrice();
        $subtotal       = $taxSubtotal      = $item->getRowTotal();
        $baseSubtotal   = $baseTaxSubtotal  = $item->getBaseRowTotal();
        $taxOnOrigPrice = !$this->_helper->applyTaxOnCustomPrice($this->_store) && $item->hasCustomPrice();
        if ($taxOnOrigPrice) {
            $origSubtotal       = $item->getOriginalPrice() * $qty;
            $baseOrigSubtotal   = $item->getBaseOriginalPrice() * $qty;
        }

        $item->setTaxPercent($rate);
        if ($this->_config->priceIncludesTax($this->_store)) {
            if ($this->_areTaxRequestsSimilar) {
                $rowTax         = $this->_calculator->calcTaxAmount($subtotal, $rate, true);
                $baseRowTax     = $this->_calculator->calcTaxAmount($baseSubtotal, $rate, true);
                $taxPrice       = $price;
                $baseTaxPrice   = $basePrice;
                $taxSubtotal    = $subtotal;
                $baseTaxSubtotal= $baseSubtotal;
                $subtotal       = $subtotal - $rowTax;
                $baseSubtotal   = $baseSubtotal - $baseRowTax;
                $price          = $this->_calculator->round($subtotal/$qty);
                $basePrice      = $this->_calculator->round($baseSubtotal/$qty);
                if ($taxOnOrigPrice) {
                    $taxable        = $origSubtotal;
                    $baseTaxable    = $baseOrigSubtotal;
                } else {
                    $taxable        = $taxSubtotal;
                    $baseTaxable    = $baseTaxSubtotal;
                }
                $isPriceInclTax = true;
            } else {
                $storeRate      = $this->_calculator->getStoreRate($request, $this->_store);
                $storeTax       = $this->_calculator->calcTaxAmount($subtotal, $storeRate, true, false);
                $baseStoreTax   = $this->_calculator->calcTaxAmount($baseSubtotal, $storeRate, true, false);
                $subtotal       = $this->_calculator->round($subtotal - $storeTax);
                $baseSubtotal   = $this->_calculator->round($baseSubtotal - $baseStoreTax);
                $price          = $this->_calculator->round($subtotal/$qty);
                $basePrice      = $this->_calculator->round($baseSubtotal/$qty);

                $rowTax         = $this->_calculator->calcTaxAmount($subtotal, $rate, false);
                $baseRowTax     = $this->_calculator->calcTaxAmount($baseSubtotal, $rate, false);
                $taxSubtotal    = $subtotal + $rowTax;
                $baseTaxSubtotal= $baseSubtotal + $baseRowTax;
                $taxPrice       = $this->_calculator->round($taxSubtotal/$qty);
                $baseTaxPrice   = $this->_calculator->round($baseTaxSubtotal/$qty);
                if ($taxOnOrigPrice) {
                    $taxable        = $this->_calculator->round($origSubtotal - $storeTax);
                    $baseTaxable    = $this->_calculator->round($baseOrigSubtotal - $baseStoreTax);
                } else {
                    $taxable        = $subtotal;
                    $baseTaxable    = $baseSubtotal;
                }
                $isPriceInclTax = false;
            }
        } else {
            $rowTax     = $this->_calculator->calcTaxAmount($subtotal, $rate, false);
            $baseRowTax = $this->_calculator->calcTaxAmount($baseSubtotal, $rate, false);
            $taxSubtotal    = $subtotal + $rowTax;
            $baseTaxSubtotal= $baseSubtotal + $baseRowTax;
            $taxPrice       = $this->_calculator->round($taxSubtotal/$qty);
            $baseTaxPrice   = $this->_calculator->round($baseTaxSubtotal/$qty);
            if ($taxOnOrigPrice) {
                $taxable        = $origSubtotal;
                $baseTaxable    = $baseOrigSubtotal;
            } else {
                $taxable        = $subtotal;
                $baseTaxable    = $baseSubtotal;
            }
            $isPriceInclTax = false;
        }

        if ($item->hasCustomPrice()) {
            $item->setCustomPrice($price);
            $item->setBaseCustomPrice($basePrice);
        } else {
            $item->setOriginalPrice($price);
        }
        $item->setPrice($basePrice);
        $item->setBasePrice($basePrice);
        $item->setRowTotal($subtotal);
        $item->setBaseRowTotal($baseSubtotal);
        $item->setPriceInclTax($taxPrice);
        $item->setBasePriceInclTax($baseTaxPrice);
        $item->setRowTotalInclTax($taxSubtotal);
        $item->setBaseRowTotalInclTax($baseTaxSubtotal);
        $item->setTaxableAmount($taxable);
        $item->setBaseTaxableAmount($baseTaxable);
        $item->setIsPriceInclTax($isPriceInclTax);
        if ($this->_config->discountTax($this->_store)) {
            $item->setDiscountCalculationPrice($taxSubtotal/$qty);
            $item->setBaseDiscountCalculationPrice($baseTaxSubtotal/$qty);
        } elseif ($isPriceInclTax) {
            $item->setDiscountCalculationPrice($subtotal/$qty);
            $item->setBaseDiscountCalculationPrice($baseSubtotal/$qty);
        }

        return $this;
    }

    /**
     * Calculate item price and row total including/excluding tax based on total price rounding level
     *
     * @param Mage_Sales_Model_Quote_Item_Abstract $item
     * @param Varien_Object $request
     * @return Mage_Tax_Model_Sales_Total_Quote_Subtotal
     */
    protected function _totalBaseCalculation($item, $request)
    {
        $calc   = $this->_calculator;
        $rate   = $calc->getRate($request->setProductClassId($item->getProduct()->getTaxClassId()));
        $qty    = $item->getTotalQty();

        $price          = $taxPrice         = $item->getCalculationPrice();
        $basePrice      = $baseTaxPrice     = $item->getBaseCalculationPrice();
        $subtotal       = $taxSubtotal      = $item->getRowTotal();
        $baseSubtotal   = $baseTaxSubtotal  = $item->getBaseRowTotal();
        $taxOnOrigPrice = !$this->_helper->applyTaxOnCustomPrice($this->_store) && $item->hasCustomPrice();
        if ($taxOnOrigPrice) {
            $origSubtotal       = $item->getOriginalPrice() * $qty;
            $baseOrigSubtotal   = $item->getBaseOriginalPrice() * $qty;
        }
        $item->setTaxPercent($rate);
        if ($this->_config->priceIncludesTax($this->_store)) {
            if ($this->_areTaxRequestsSimilar) {
                $rowTax         = $this->_deltaRound($calc->calcTaxAmount($subtotal, $rate, true, false), $rate, true);
                $baseRowTax     = $this->_deltaRound($calc->calcTaxAmount($baseSubtotal, $rate, true, false), $rate, true, 'base');
                $taxPrice       = $price;
                $baseTaxPrice   = $basePrice;
                $taxSubtotal    = $subtotal;
                $baseTaxSubtotal= $baseSubtotal;
                $subtotal       = $subtotal - $rowTax;
                $baseSubtotal   = $baseSubtotal - $baseRowTax;
                $price          = $calc->round($subtotal/$qty);
                $basePrice      = $calc->round($baseSubtotal/$qty);
                if ($taxOnOrigPrice) {
                    $taxable        = $origSubtotal;
                    $baseTaxable    = $baseOrigSubtotal;
                } else {
                    $taxable        = $taxSubtotal;
                    $baseTaxable    = $baseTaxSubtotal;
                }
                $isPriceInclTax = true;
            } else {
                $storeRate      = $calc->getStoreRate($request, $this->_store);
                $storeTax       = $calc->calcTaxAmount($subtotal, $storeRate, true, false);
                $baseStoreTax   = $calc->calcTaxAmount($baseSubtotal, $storeRate, true, false);
                $subtotal       = $calc->round($subtotal - $storeTax);
                $baseSubtotal   = $calc->round($baseSubtotal - $baseStoreTax);
                $price          = $calc->round($subtotal/$qty);
                $basePrice      = $calc->round($baseSubtotal/$qty);

                $rowTax         = $this->_deltaRound($calc->calcTaxAmount($subtotal, $rate, false, false), $rate, true);
                $baseRowTax     = $this->_deltaRound($calc->calcTaxAmount($baseSubtotal, $rate, false, false), $rate, true, 'base');
                $taxSubtotal    = $subtotal + $rowTax;
                $baseTaxSubtotal= $baseSubtotal + $baseRowTax;
                $taxPrice       = $calc->round($taxSubtotal/$qty);
                $baseTaxPrice   = $calc->round($baseTaxSubtotal/$qty);
                if ($taxOnOrigPrice) {
                    $taxable        = $calc->round($origSubtotal - $storeTax);
                    $baseTaxable    = $calc->round($baseOrigSubtotal - $baseStoreTax);
                } else {
                    $taxable        = $subtotal;
                    $baseTaxable    = $baseSubtotal;
                }
                $isPriceInclTax = false;
            }
        } else {
            $rowTax         = $this->_deltaRound($calc->calcTaxAmount($subtotal, $rate, false, false), $rate, true);
            $baseRowTax     = $this->_deltaRound($calc->calcTaxAmount($baseSubtotal, $rate, false, false), $rate, true, 'base');
            $taxSubtotal    = $subtotal + $rowTax;
            $baseTaxSubtotal= $baseSubtotal + $baseRowTax;
            $taxPrice       = $calc->round($taxSubtotal/$qty);
            $baseTaxPrice   = $calc->round($baseTaxSubtotal/$qty);
            if ($taxOnOrigPrice) {
                $taxable        = $origSubtotal;
                $baseTaxable    = $baseOrigSubtotal;
            } else {
                $taxable        = $subtotal;
                $baseTaxable    = $baseSubtotal;
            }
            $isPriceInclTax = false;
        }

        if ($item->hasCustomPrice()) {
            $item->setCustomPrice($price);
            $item->setBaseCustomPrice($basePrice);
        } else {
            $item->setOriginalPrice($price);
        }
        $item->setPrice($basePrice);
        $item->setBasePrice($basePrice);
        $item->setRowTotal($subtotal);
        $item->setBaseRowTotal($baseSubtotal);
        $item->setPriceInclTax($taxPrice);
        $item->setBasePriceInclTax($baseTaxPrice);
        $item->setRowTotalInclTax($taxSubtotal);
        $item->setBaseRowTotalInclTax($baseTaxSubtotal);
        $item->setTaxableAmount($taxable);
        $item->setBaseTaxableAmount($baseTaxable);
        $item->setIsPriceInclTax($isPriceInclTax);
        if ($this->_config->discountTax($this->_store)) {
            $item->setDiscountCalculationPrice($taxSubtotal/$qty);
            $item->setBaseDiscountCalculationPrice($baseTaxSubtotal/$qty);
        } elseif ($isPriceInclTax) {
            $item->setDiscountCalculationPrice($subtotal/$qty);
            $item->setBaseDiscountCalculationPrice($baseSubtotal/$qty);
        }
        return $this;
    }

    /**
     * Round price based on previous rounding operation delta
     *
     * @param float $price
     * @param string $rate
     * @param bool $direction
     * @param string $type
     * @return float
     */
    protected function _deltaRound($price, $rate, $direction, $type='regular')
    {
        if ($price) {
            $rate   = (string) $rate;
            $type   = $type.$direction;
            $delta  = isset($this->_roundingDeltas[$type][$rate]) ? $this->_roundingDeltas[$type][$rate] : 0;
            $price  += $delta;
            $this->_roundingDeltas[$type][$rate] = $price - $this->_calculator->round($price);
            $price = $this->_calculator->round($price);
        }
        return $price;
    }

    /**
     * Recalculate row information for item based on children calculation
     *
     * @param   Mage_Sales_Model_Quote_Item_Abstract $item
     * @return  Mage_Tax_Model_Sales_Total_Quote_Subtotal
     */
    protected function _recalculateParent(Mage_Sales_Model_Quote_Item_Abstract $item)
    {
        $price       = 0;
        $basePrice   = 0;
        $rowTotal    = 0;
        $baseRowTotal= 0;
        $priceInclTax       = 0;
        $basePriceInclTax   = 0;
        $rowTotalInclTax    = 0;
        $baseRowTotalInclTax= 0;
        foreach ($item->getChildren() as $child) {
            $price              += $child->getOriginalPrice();
            $basePrice          += $child->getBaseOriginalPrice();
            $rowTotal           += $child->getRowTotal();
            $baseRowTotal       += $child->getBaseRowTotal();
            $priceInclTax       += $child->getPriceInclTax();
            $basePriceInclTax   += $child->getBasePriceInclTax();
            $rowTotalInclTax    += $child->getRowTotalInclTax();
            $baseRowTotalInclTax+= $child->getBaseRowTotalInclTax();
        }
        $item->setOriginalPrice($price);
        $item->setPrice($basePrice);
        $item->setRowTotal($rowTotal);
        $item->setBaseRowTotal($baseRowTotal);
        $item->setPriceInclTax($priceInclTax);
        $item->setBasePriceInclTax($basePriceInclTax);
        $item->setRowTotalInclTax($rowTotalInclTax);
        $item->setBaseRowTotalInclTax($baseRowTotalInclTax);
        return $this;
    }

    /**
     * Get request for fetching store tax rate
     *
     * @param   Mage_Sales_Model_Quote_Address $address
     * @return  Varien_Object
     */
    protected function _getStoreTaxRequest($address)
    {
        if (is_null($this->_storeTaxRequest)) {
            $this->_storeTaxRequest = $this->_calculator->getRateOriginRequest($address->getQuote()->getStore());
        }
        return $this->_storeTaxRequest;
    }

    /**
     * Get request for fetching address tax rate
     *
     * @param   Mage_Sales_Model_Quote_Address $address
     * @return  Varien_Object
     */
    protected function _getAddressTaxRequest($address)
    {
        $addressTaxRequest = $this->_calculator->getRateRequest(
            $address,
            $address->getQuote()->getBillingAddress(),
            $address->getQuote()->getCustomerTaxClassId(),
            $address->_store
        );
        return $addressTaxRequest;
    }

    /**
     * Add row total item amount to subtotal
     *
     * @param   Mage_Sales_Model_Quote_Address $address
     * @param   Mage_Sales_Model_Quote_Item_Abstract $item
     * @return  Mage_Tax_Model_Sales_Total_Quote_Subtotal
     */
    protected function _addSubtotalAmount(Mage_Sales_Model_Quote_Address $address, $item)
    {
        $address->setTotalAmount('subtotal', $address->getTotalAmount('subtotal')+$item->getRowTotal());
        $address->setBaseTotalAmount('subtotal', $address->getBaseTotalAmount('subtotal')+$item->getBaseRowTotal());
        $address->setSubtotalInclTax($address->getSubtotalInclTax()+$item->getRowTotalInclTax());
        $address->setBaseSubtotalInclTax($address->getBaseSubtotalInclTax()+$item->getBaseRowTotalInclTax());
        return $this;
    }














    /**
     * Unset item prices/totals with price include tax.
     * Operation is necessary for reset item state in case if configuration was changed
     *
     * @deprecated after 1.4.1
     * @param   Mage_Sales_Model_Quote_Item_Abstract $item
     * @return  Mage_Tax_Model_Sales_Total_Quote_Subtotal
     */
    protected function _resetItemPriceInclTax(Mage_Sales_Model_Quote_Item_Abstract $item)
    {
        $item->setPriceInclTax(null);
        $item->setBasePriceInclTax(null);
        $item->setRowTotalInclTax(null);
        $item->setBaseRowTotalInclTax(null);
        return $this;
    }

    /**
     *
     * @deprecated after 1.4.0.1
     * @param   Mage_Sales_Model_Quote_Address $address
     * @return  Mage_Tax_Model_Sales_Total_Quote_Subtotal
     */
    protected function _processShippingAmount($address)
    {
        return $this;
    }

    /**
     * Recollect item price and row total using after taxes subtract.
     * Declare item price including tax attributes
     * @deprecated after 1.4.1
     * @param   Mage_Sales_Model_Quote_Item_Abstract $item
     * @return  Mage_Tax_Model_Sales_Total_Quote_Subtotal
     */
    protected function _recollectItem($address, Mage_Sales_Model_Quote_Item_Abstract $item)
    {
        $store   = $address->getQuote()->getStore();
        $request = $this->_getStoreTaxRequest($address);
        $request->setProductClassId($item->getProduct()->getTaxClassId());
        $rate   = $this->_calculator->getRate($request);
        $qty    = $item->getTotalQty();

        $price          = $taxPrice         = $item->getCalculationPrice();
        $basePrice      = $baseTaxPrice     = $item->getBaseCalculationPrice();
        $subtotal       = $taxSubtotal      = $item->getRowTotal();
        $baseSubtotal   = $baseTaxSubtotal  = $item->getBaseRowTotal();

        if ($this->_config->discountTax($store)) {
            $item->setDiscountCalculationPrice($price);
            $item->setBaseDiscountCalculationPrice($basePrice);
        }

        /**
         * Use original price for tax calculation
         */
        if ($item->hasCustomPrice() && !$this->_helper->applyTaxOnCustomPrice($store)) {
            $taxPrice         = $item->getOriginalPrice();
            $baseTaxPrice     = $item->getBaseOriginalPrice();
            $taxSubtotal      = $taxPrice*$qty;
            $baseTaxSubtotal  = $baseTaxPrice*$qty;
        }

        if ($this->_areTaxRequestsSimilar) {
            $item->setRowTotalInclTax($subtotal);
            $item->setBaseRowTotalInclTax($baseSubtotal);
            $item->setPriceInclTax($price);
            $item->setBasePriceInclTax($basePrice);

            $item->setTaxCalcPrice($taxPrice);
            $item->setBaseTaxCalcPrice($baseTaxPrice);
            $item->setTaxCalcRowTotal($taxSubtotal);
            $item->setBaseTaxCalcRowTotal($baseTaxSubtotal);
        }

        $this->_subtotalInclTax     += $subtotal;
        $this->_baseSubtotalInclTax += $baseSubtotal;

        if ($this->_config->getAlgorithm($store) == Mage_Tax_Model_Calculation::CALC_UNIT_BASE) {
            $taxAmount      = $this->_calculator->calcTaxAmount($taxPrice, $rate, true);
            $baseTaxAmount  = $this->_calculator->calcTaxAmount($baseTaxPrice, $rate, true);
            $unitPrice      = $this->_calculator->round($price-$taxAmount);
            $baseUnitPrice  = $this->_calculator->round($basePrice-$baseTaxAmount);
            $subtotal       = $this->_calculator->round($unitPrice*$qty);
            $baseSubtotal   = $this->_calculator->round($baseUnitPrice*$qty);
        } else {
            $taxAmount      = $this->_calculator->calcTaxAmount($taxSubtotal, $rate, true, false);
            $baseTaxAmount  = $this->_calculator->calcTaxAmount($baseTaxSubtotal, $rate, true, false);
            $unitPrice      = ($subtotal-$taxAmount)/$qty;
            $baseUnitPrice  = ($baseSubtotal-$baseTaxAmount)/$qty;
            $subtotal       = $this->_calculator->round(($subtotal-$taxAmount));
            $baseSubtotal   = $this->_calculator->round(($baseSubtotal-$baseTaxAmount));
        }

        if ($item->hasCustomPrice()) {
            $item->setCustomPrice($unitPrice);
            $item->setBaseCustomPrice($baseUnitPrice);
        }
        $item->setPrice($baseUnitPrice);
        $item->setOriginalPrice($unitPrice);
        $item->setBasePrice($baseUnitPrice);
        $item->setRowTotal($subtotal);
        $item->setBaseRowTotal($baseSubtotal);
        return $this;
    }

    /**
     * Check if we need subtract store tax amount from item prices
     *
     * @deprecated after 1.4.1
     * @param Mage_Sales_Model_Quote_Address $address
     * @return bool
     */
    protected function _needSubtractTax($address)
    {
        $store = $address->getQuote()->getStore();
        if ($this->_config->priceIncludesTax($store) || $this->_config->getNeedUsePriceExcludeTax()) {
            return true;
        }
        return false;
    }

    /**
     * @deprecated after 1.4.0.1
     *
     * @param Mage_Sales_Model_Quote_Address $address
     * @return bool
     */
    protected function _needSubtractShippingTax($address)
    {
        $store = $address->getQuote()->getStore();
        if ($this->_config->shippingPriceIncludesTax($store) || $this->_config->getNeedUseShippingExcludeTax()) {
            return true;
        }
        return false;
    }
}