ecommerce_cart_processor.inc

<?php
/*
* Ecommerce Package Cart Processor Object
*
* This object handles the interactions with the ecommerce cart, either stored in
* $_SESSION (the default), or passed in by the caller
*
* @author Robert Howard <rhoward@squiz.net>
* @author Luke Wright <lwright@squiz.net>
* @author Andrei Railean <arailean@squiz.net>
* @version $Revision: 1.29.2.1 $
* @package MySource_Matrix_Packages
* @subpackage ecommerce
*/


class Ecommerce_Cart_Processor
{

    var $cart = NULL;


    function Ecommerce_Cart_Processor($checkout_id = 0)
    {
        // set, but rely on external objects to initialise
        $this->setCartContainer($_SESSION['sq_cart_contents'][$checkout_id]);

        if (is_null($this->cart)) $this->initialiseCart();

    }//end constructor


    function setCartContainer(&$cart)
    {
        $this->cart =& $cart;

    }//end setCartContainer()


    function initialiseCart()
    {
        $ret_val = 0;

        if (is_null($this->cart)) {
            $this->cart = Array();
            $ret_val = 1;
        }

        return $ret_val;

    }//end initialiseCart()


    function clearCart()
    {
        $this->cart = Array();
        return TRUE;

    }//end clearCart()


    function &getItem($assetid)
    {
        if (!empty($this->cart[$assetid])) {
            return $this->cart[$assetid];
        } else {
            return FALSE;
        }

    }//end getItem()


    function &getCart()
    {
        // remove any invalid cart items
        $this->validateCart();

        return $this->cart;

    }//end getCart()


    function getTotal($taxation_cost=0.0, $taxation_rate=0.0)
    {
        $total = 0.00;
        foreach ($this->cart as $assetid => $details) {
            // -1 == value not known
            if ($details['price'] != -1) {
                // adjust product prices
                $has_tax = array_get_index($details, 'has_tax', FALSE);
                $calculate_tax = array_get_index($details, 'taxable', FALSE);
                if ($calculate_tax) {
                    $item_costs = $this->_calculateItemCosts($details['price'], $taxation_rate, $has_tax);
                    $cost = $item_costs['tax_adjusted_cost'];
                } else {
                    $cost = $details['price'];
                }

                $total += $details['quantity'] * $cost;
            }
        }

        $total += $taxation_cost;
        return $total;

    }//end getTotal()


    function getGrandTotalExDelivery($taxation_rate, $remove_tax, $flat_charges)
    {
        $total_tax = $this->getTotalTax($taxation_rate);
        $flat_charges_total = $this->getFlatChargesTotal($flat_charges);

        if ($remove_tax) {
            $grand_total = ($this->getTotal($total_tax, $taxation_rate) + $flat_charges_total) - $total_tax;
        } else {
            $grand_total = $this->getTotal($total_tax, $taxation_rate) + $flat_charges_total;
        }

        return $grand_total;

    }//end getGrandTotalExDelivery()


    function getFlatChargesTotal($flat_charges)
    {
        $flat_charges_total = 0.0;
        foreach ($flat_charges as $name => $price) {
            $flat_charges_total += $price;
        }

        return $flat_charges_total;

    }//end getFlatChargesTotal()


    function getTotalDeliveryCosts($grand_total)
    {
        $total_delivery_cost = 0.00;
        if (isset($_SESSION['sq_region_specific'])) {
            foreach ($this->cart as $assetid => $details) {
                //if the asset (product) is not a donation, calculate delivery prices per weight metric
                if (!array_get_index($details, 'is_donation', FALSE) && isset($_SESSION['sq_region_specific']['delivery_weight_fee'])) {
                    $delivery_weight_fee = $_SESSION['sq_region_specific']['delivery_weight_fee'];
                    // it will either be a metadata field or an asset attribute that we have to get weight info from
                    if (isset($_SESSION['sq_region_specific']['delivery_weight_fee']['metadata_fieldid'])) {
                        $fieldid = $_SESSION['sq_region_specific']['delivery_weight_fee']['metadata_fieldid'];
                        $mm =& $GLOBALS['SQ_SYSTEM']->getMetadataManager();
                        $weight = (float) $mm->getMetadataValueByAssetid($assetid, $fieldid);
                    } else if (isset($_SESSION['sq_region_specific']['delivery_weight_fee']['attribute_name'])) {
                        $attribute_name = $_SESSION['sq_region_specific']['delivery_weight_fee']['attribute_name'];
                        $asset =& $GLOBALS['SQ_SYSTEM']->am->getAsset($assetid);
                        $weight = (float) $asset->attr($attribute_name);
                    }

                    if (isset($weight) && !empty($weight)) {
                        $product_quantity = array_get_index($details, 'quantity', 0);
                        
                        if (isset($delivery_weight_fee['max_quantity']) && ($delivery_weight_fee['max_quantity'] < $product_quantity)) {
                            $product_quantity = $delivery_weight_fee['max_quantity'];
                        }
                        
                        $total_delivery_cost += $weight * $delivery_weight_fee['fee'] * $product_quantity;
                    }
                }//end if
            }//end for
        }//end if

        // calculate international delivery fee
        if (isset($_SESSION['sq_region_specific']['international_delivery_fee'])) {
            $total_delivery_cost += $_SESSION['sq_region_specific']['international_delivery_fee'];
        }

        // calculate additional conditional delivery fees
        // based on total of cart contents plus all existing delivery fees
        if (isset($_SESSION['sq_region_specific']['conditions'])) {
            $grand_total_plus_delivery = $grand_total + $total_delivery_cost;
            $conditions = $_SESSION['sq_region_specific']['conditions'];
            foreach ($conditions as $key => $data) {
                // evaluate each condition
                $operator = print_r($data['operator'], TRUE);
                if (eval('$satisfied = $grand_total_plus_delivery'.$operator.'$data[\'comparison_price\']; return $satisfied;')) {
                    if ($data['remove_fees']) {
                        $total_delivery_cost = 0;
                    } else {
                        $total_delivery_cost += $data['additional_cost'];
                    }
                    // evaluate only the first condition satisfied
                    break;
                }
            }
        }

        //cap the delivery fee if the maximum delivery fee is set
        if (isset($_SESSION['sq_region_specific']['max_delivery_fee']) && ($_SESSION['sq_region_specific']['max_delivery_fee'] < $total_delivery_cost)) {
            $total_delivery_cost = $_SESSION['sq_region_specific']['max_delivery_fee'];
        }
        
        return $total_delivery_cost;

    }//end getTotalDeliveryCosts()


    function getTotalTax($taxation_rate=0.0)
    {
        $total_tax = 0.00;
        foreach ($this->cart as $assetid => $details) {
            // -1 == value not known
            if (($details['price'] != -1) && ($details['taxable'])) {
                $has_tax = array_get_index($details, 'has_tax', FALSE);
                $item_costs = $this->_calculateItemCosts($details['price'], $taxation_rate, $has_tax);
                $tax_cost = $item_costs['tax_cost'];

                $total_tax += $details['quantity'] * $tax_cost;
            }
        }

        return $total_tax;

    }//end getTotalTax()


    function _calculateItemCosts($cost, $taxation_rate, $has_tax)
    {
        // deduct tax or add tax depending on whether item currently has tax included in its price
        if ($has_tax) {
            // deduct tax and alter product cost as well to reflect this
            $tax_cost = $cost - ($cost / (1 + $taxation_rate));
            $cost = $cost - $tax_cost;
        } else {
            // add tax
            $tax_cost = $cost * $taxation_rate;
        }
        $item_costs = Array(
                        'tax_adjusted_cost' => $cost,
                        'tax_cost'          => $tax_cost,
                      );

        return $item_costs;

    }// end _calculateItemCosts()


    function getCount()
    {
        if (is_null($this->cart)) return 0;
        $count = 0;
        foreach ($this->cart as $assetid => $details) {
            if (!array_get_index($details, 'is_donation', FALSE)) {
                $count += $details['quantity'];
            }
        }

        return $count;

    }//end getCount()


    function getUniqueCount()
    {
        return count($this->cart);

    }//end getUniqueCount()


    function addItem($assetid, $quantity=1)
    {
        $asset = $GLOBALS['SQ_SYSTEM']->am->getAsset($assetid);
        if (is_null($asset)) {
            return FALSE;
        }
        
        if (!($asset instanceof Donation) && !($asset instanceof Buyable)) {
            trigger_localised_error('ECOM0005', E_USER_WARNING, $assetid);
            return FALSE;
        }
        
        if ($quantity <= 0) {
            if ($asset instanceof Donation) {
                trigger_localised_error('ECOM0025', E_USER_WARNING);
            } else if ($quantity < 0) { // quantity is less than zero, throw a hissy fit
                trigger_localised_error('ECOM0004', E_USER_WARNING);
            }
            return FALSE;
        }


        if (!isset($this->cart[$assetid])) {
            // ugly, but we need to work around the backwards way Files store names
            if ($asset instanceof File) {
                $name = $asset->attr('title');
            } else {
                $name = $asset->name;
            }

            // only include a price if the object is a product
            // only include taxable boolean if the object is a product
            $taxable = FALSE;
            $has_tax = FALSE;
            $is_donation = FALSE;
            $refund_type = 0;
            $product_code = '';
            $financial_code = '';

            if ($asset instanceof Donation) {
                $price = 1;
                $is_donation = TRUE;
            } else if ($asset instanceof Product) {
                $price = $asset->attr('price');

                $refund_type = $asset->attr('refund_type');
                $product_code = $asset->attr('product_code');
                $financial_code = $asset->attr('financial_code');

                // get the taxable boolean
                $tmp_price_obj = $asset->attr('price_obj');
                if (!empty($tmp_price_obj) ) {
                    if ((!empty($tmp_price_obj->value_has_tax)) && ($tmp_price_obj->value_has_tax == 1)) {
                        $has_tax = TRUE;
                    }
                    if ((!empty($tmp_price_obj->calculate_tax)) && ($tmp_price_obj->calculate_tax == 1)) {
                        $taxable = TRUE;
                    }
                }
            } else {
                $price = -1;
            }

            $this->cart[$assetid] = Array(
                                        'price'             => $price,
                                        'quantity'          => $quantity,
                                        'name'              => $name,
                                        'has_tax'           => $has_tax,
                                        'taxable'           => $taxable,
                                        'is_donation'       => $is_donation,
                                        'refund_type'       => $refund_type,
                                        'product_code'      => $product_code,
                                        'financial_code'    => $financial_code,
                                    );
            $GLOBALS['SQ_SYSTEM']->am->forgetAsset($asset);
            
        } else {
            if ($asset instanceof Donation) {
                $this->cart[$assetid]['quantity'] = $quantity;
            } else {
                $this->cart[$assetid]['quantity'] += $quantity;
            }
        }//end if

        return TRUE;

    }//end addItem()


    function updateItem($assetid, $quantity)
    {
        // item doesn't exist in cart, then silently redirect to addItem()
        if (!isset($this->cart[$assetid])) {
            return $this->addItem($assetid, $quantity);
        }

        // if we are not updating anything, silently return
        if (array_get_index($this->cart[$assetid], 'quantity', 0) == $quantity) {
            return FALSE;
        }

        // Qty < 0, throw an error
        if ($quantity < 0) {
            trigger_localised_error('ECOM0010', E_USER_WARNING);
            return FALSE;
        } else if ($quantity == 0) {
            $this->removeItem($assetid);
        } else if (isset($this->cart[$assetid]['quantity']) && $this->cart[$assetid]['quantity'] == $quantity) {
            // not updating, so fail
            return FALSE;
        } else {
            $this->cart[$assetid]['quantity'] = $quantity;
        }

        return TRUE;

    }//end updateItem()


    function removeItem($assetid, $quantity=NULL)
    {
        // item doesn't exist in cart - if the quantity is zero (or ALL)
        // then silently return, otherwise error
        if (!isset($this->cart[$assetid])) {
            if ($quantity > 0) {
                trigger_localised_error('ECOM0006', E_USER_WARNING);
            }
            return FALSE;
        }

        // after this point we can assume that asset exists in the cart
        // quantity is null, remove everything
        if (is_null($quantity)) {
            $quantity = $this->cart[$assetid]['quantity'];
        }

        // qty == 0, silently return - Qty < 0, throw an error
        if ($quantity <= 0) {
            if ($quantity < 0) {
                trigger_localised_error('ECOM0007', E_USER_WARNING);
            }
            return FALSE;
        }

        if ($quantity > $this->cart[$assetid]['quantity']) {
            trigger_localised_error('ECOM0008', E_USER_WARNING);
            return FALSE;
        } else if ($quantity == $this->cart[$assetid]['quantity']) {
            unset($this->cart[$assetid]);
        } else {
            $this->cart[$assetid]['quantity'] -= $quantity;
        }

        return TRUE;

    }//end removeItem()


    function hashCart()
    {
        // don't grab by reference, because we're sorting and mucking around with the array
        $tmp_cart = $this->cart;
        ksort($tmp_cart);
        $hash = md5(serialize($tmp_cart));

        return $hash;

    }//end hashCart()


    function printReceipt($taxation_name='GST', $taxation_rate=0, $flat_charges=Array(), $remove_tax=FALSE, $currency_symbol='$', $float_precision=2, $refund_info='')
    {
        if (empty($this->cart)) return;

        // ensure the float precision is an int
        $float_precision = (int) $float_precision;
        $price_format = $currency_symbol.'%.'.$float_precision.'f';
        
        $name_length = 0;
        $has_price = FALSE;
        $has_products = FALSE;
        
        // TRUE if any item in cart is non-refundable
        $non_refundable_flag = FALSE;
        
        // formatting preparation
        foreach ($this->cart as $assetid => $details) {
            // determine longest item name

            $tmp_taxable = array_get_index($details, 'taxable', FALSE);
            $product_name = array_get_index($details, 'name', '');
            
            if (!$non_refundable_flag) {
                $refund_type = array_get_index($details, 'refund_type', 'NonRefundable');
                $non_refundable_flag = ($refund_type === 'NonRefundable') ? TRUE : FALSE;
            }
            
            if (strlen($product_name) > $name_length) {
                $name_length = strlen(array_get_index($details, 'name', ''));
            }
            if ($tmp_taxable) {
                if (strlen('Excluded Tax ('.$taxation_name.')') > $name_length) {
                    $name_length = strlen('Excluded Tax ('.$taxation_name.')');
                }
            }

            // determine whether all items have price
            $price = array_get_index($details, 'price', -1);
            if (!$has_price && ($price != -1)) {
                $has_price = TRUE;
            }
            
            // check if there are not only donations
            if (!$has_products && !array_get_index($details, 'is_donation', FALSE) && ($price != -1)) {
                $has_products = TRUE;
            }
        }

        // calculate the longest item name and calculate the number of flat_charges
        $flat_charges_total = 0.0;
        foreach ($flat_charges as $name => $price) {
            if (strlen($name) > $name_length) {
                $name_length = strlen($name);
            }
            $flat_charges_total += $price;
        }

        // standard format for the receipt header and rows
        $row_format = '%-'.$name_length.'s %10s'.($has_price && $has_products ? ' %10s' : '')."\n";

        if ($has_price) {
            if ($has_products) {
                $header = sprintf($row_format, 'Item', 'Quantity', 'Price');
            } else { // there are donations only
                $header = sprintf($row_format, 'Item', 'Amount');
            }
        } else {
            $header = sprintf($row_format, 'Item', 'Quantity');
        }

        $break = '';
        for ($ii = 1; $ii < strlen($header); $ii++) {
            $break .= '-';
        }
        $break .= "\n";

        echo $header;
        echo $break;

        // print each row
        foreach ($this->cart as $assetid => $details) {
            $cost = array_get_index($details, 'price', 0);
            // calculate tax for this item only if we are not removing tax
            $has_tax = array_get_index($details, 'has_tax', FALSE);
            $calculate_tax = array_get_index($details, 'taxable', FALSE);
            if ($calculate_tax) {
                $item_costs = $this->_calculateItemCosts($cost, $taxation_rate, $has_tax);
                $cost = $item_costs['tax_adjusted_cost'];
                $tax_cost = $item_costs['tax_cost'];
            } else {
                $tax_cost = 0;
            }

            $product_quantity = array_get_index($details, 'quantity', 0);

            if ($cost < 0) {
                $cost = '';
            } else {
                $cost = sprintf($price_format, $cost * $product_quantity);
                $tax_cost = sprintf($price_format, $tax_cost * $product_quantity);
            }

            if ($has_price) {
                if ($has_products) {
                    if (array_get_index($details, 'is_donation', FALSE)) {
                        $product_quantity = '';
                    }
                    printf($row_format, array_get_index($details, 'name', ''), $product_quantity, $cost);
                } else {
                    printf($row_format, array_get_index($details, 'name', ''), $cost);
                }
            } else {
                printf($row_format, array_get_index($details, 'name', ''), $product_quantity);
            }
        }//end foreach

        echo $break;

        // change the row format for the totals line
        $row_format = '%'.$name_length.'s %10s'.($has_price && $has_products ? ' %10s' : '')."\n";

        if ($has_price) {
            $total_tax = $this->getTotalTax($taxation_rate);

            $sub_total = $remove_tax ? $this->getTotal($total_tax, $taxation_rate)-$total_tax : $this->getTotal(0, $taxation_rate);
            
            if ($has_products) {
                echo sprintf($row_format, 'Total', $this->getCount(), sprintf($price_format, $sub_total));
            } else {
                echo sprintf($row_format, 'Total', sprintf($price_format, $sub_total));
            }

            if (($total_tax > 0) || ($flat_charges_total > 0.0)) {
                if ($total_tax > 0) {
                    $row_title = $remove_tax ? 'Excluded Tax ('.$taxation_name.')' : 'Total ('.$taxation_name.')';
                    echo sprintf($row_format, $row_title, $this->getCount(), sprintf($price_format, $total_tax));
                }
                echo $break;
                foreach ($flat_charges as $name => $price) {
                    echo sprintf($row_format, $name, '', sprintf($price_format, $price));
                }

                $grand_total_ex_delivery = $this->getGrandTotalExDelivery($taxation_rate, $remove_tax, $flat_charges);

                $total_delivery_cost = $this->getTotalDeliveryCosts($grand_total_ex_delivery);

                if ($total_delivery_cost > 0) {
                    echo sprintf($row_format, 'Delivery Fee', '', sprintf($price_format, $total_delivery_cost));
                }

                // figure out whether to print this last line break
                if (($total_delivery_cost > 0) || ($flat_charges_total > 0)) {
                    echo $break;
                }
                echo sprintf($row_format, 'Grand Total', '', sprintf($price_format, $grand_total_ex_delivery + $total_delivery_cost));
            }
            if (!empty($refund_info) && $non_refundable_flag) {
                echo "\n".$refund_info."\n";
            }
            
        } else {
            echo sprintf($row_format, 'Total', $this->getCount());
        }

        return;

    }//end printReceipt()


    function printCustomisedReceipt(&$contents_bodycopy, &$format_bodycopy, $taxation_name='GST', $taxation_rate=0, $flat_charges=Array(), $remove_tax=FALSE, $currency_symbol='$', $float_precision=2)
    {
        if (empty($this->cart)) return;

        // ensure the float precision is an int
        $float_precision = (int) $float_precision;
        $price_format = $currency_symbol.'%.'.$float_precision.'f';

        $content_keywords = $contents_bodycopy->getKeywords();
        $content_replacements = Array();

        // print each asset in the cart using the receipt type format
        $format_keywords = $format_bodycopy->getKeywords();
        ob_start();
        foreach ($this->cart as $assetid => $details) {
            $asset =& $GLOBALS['SQ_SYSTEM']->am->getAsset($assetid);
            $format_replacements = Array();

            // replace all asset based keywords
            foreach ($format_keywords as $keyword) {
                $format_replacements[$keyword] = $asset->getKeywordReplacement($keyword);
            }

            $product_quantity = array_get_index($details, 'quantity', 0);

            // calculate tax and costs for this item
            $cost = array_get_index($details, 'price', 0);
            // calculate tax for this item only if we are not removing tax
            $has_tax = array_get_index($details, 'has_tax', FALSE);
            $calculate_tax = array_get_index($details, 'taxable', FALSE);
            if ($calculate_tax) {
                $item_costs = $this->_calculateItemCosts($cost, $taxation_rate, $has_tax);
                $cost = $item_costs['tax_adjusted_cost'];
                $tax_cost = $item_costs['tax_cost'];
            } else {
                $tax_cost = 0;
            }

            // replace all ecommerce specific keywords
            if (array_get_index($details, 'is_donation', FALSE)) {
                $format_replacements['item_quantity_added'] = '';
                $format_replacements['item_price_incl_tax'] = sprintf($price_format, $product_quantity);
            } else {
                $format_replacements['item_quantity_added'] = $product_quantity;
                $format_replacements['item_price_incl_tax'] = sprintf($price_format, $cost);
            }

            $format_replacements['item_tax'] = sprintf($price_format, $tax_cost);

            $format_replacements['total_item_price'] = sprintf($price_format, $cost * $product_quantity);
            $format_replacements['total_item_tax'] = sprintf($price_format, $tax_cost * $product_quantity);

            $format_bodycopy->setKeywordReplacements($format_replacements);
            $format_bodycopy->printBody();
        }
        
        // receipt contents bodycopy keyword replacements
        $content_replacements['receipt_listing'] = ob_get_clean();

        $total_tax = $this->getTotalTax($taxation_rate);
        $content_replacements['total_tax'] = $remove_tax ? sprintf($price_format, 0) : sprintf($price_format, $total_tax);
        $content_replacements['tax_name'] = $taxation_name;

        ob_start();
        $flat_charges_total = 0.0;
        echo '<table>';
        foreach ($flat_charges as $name => $price) {
            echo '<tr><td>'.$name.':</td><td>'.sprintf($price_format, $price).'</td></tr>';
            $flat_charges_total += $price;
        }
        echo '</table>';
        $content_replacements['flat_fees_table'] = ob_get_clean();
        $content_replacements['flat_fees_total'] = sprintf($price_format, $flat_charges_total);

        $sub_total = $remove_tax ? $this->getTotal($total_tax, $taxation_rate)-$total_tax : $this->getTotal(0, $taxation_rate);
        $content_replacements['sub_total'] = sprintf($price_format, $sub_total);

        $grand_total_ex_delivery = $this->getGrandTotalExDelivery($taxation_rate, $remove_tax, $flat_charges);
        $total_delivery_cost = $this->getTotalDeliveryCosts($grand_total_ex_delivery);
        $content_replacements['delivery_total'] = sprintf($price_format, $total_delivery_cost);
        $content_replacements['grand_total'] = sprintf($price_format, $grand_total_ex_delivery + $total_delivery_cost);

        $contents_bodycopy->setKeywordReplacements($content_replacements);

        ob_start();
        $contents_bodycopy->printBody();
        $customised_receipt = ob_get_clean();

        return $customised_receipt;

    }//end printCustomisedReceipt()


    function getCartXml($taxation_name='GST', $taxation_rate=0, $flat_charges=Array(), $remove_tax=FALSE, $currency_symbol='$', $float_precision=2)
    {
        if (empty($this->cart)) return '';

        // ensure the float precision is an int
        $float_precision = (int) $float_precision;
        $price_format = '%.'.$float_precision.'f';

        //get Metadata Manager
        $mm =& $GLOBALS['SQ_SYSTEM']->getMetadataManager();
        
        $products_str = '';
        foreach ($this->cart as $assetid => $details) {
            $quantity = array_get_index($details, 'quantity', 0);

            // calculate tax and costs for this item
            $cost = array_get_index($details, 'price', 0);
            if (array_get_index($details, 'taxable', FALSE)) {
                $item_costs = $this->_calculateItemCosts($cost, $taxation_rate, array_get_index($details, 'has_tax', FALSE));
                $cost = $item_costs['tax_adjusted_cost'];
                $tax_cost = $item_costs['tax_cost'];
            } else {
                $tax_cost = 0;
            }

            //information of product is different if it is a donation
            if (array_get_index($details, 'is_donation', FALSE)) {
                $donation = 'yes';
                $cost = $quantity;
                $quantity = 1;
            } else {
                $donation = 'no';
            }

            $item_price = sprintf($price_format, $cost);
            $item_price_incl_tax = sprintf($price_format, $cost + $tax_cost);
            $total_item_price = sprintf($price_format, $cost * $quantity);
            $total_item_price_incl_tax = sprintf($price_format, ($cost + $tax_cost) * $quantity);
            $total_item_tax = sprintf($price_format, $tax_cost * $quantity);

            //get metadata of the product/donation asset
            $metadata_values = $mm->getMetadataFieldValues($assetid);
            $metadata_values_str = '';
            foreach ($metadata_values as $name => $value) {
                $metadata_values_str .= <<<HEREDOC

                    <field>
                        <name><![CDATA[$name]]></name>
                        <value><![CDATA[$value]]></value>
                    </field>
HEREDOC;
            }
            
            $metadata_str = '';
            if ($metadata_values_str != '') {
                $metadata_str = <<<HEREDOC

                <metadata>$metadata_values_str
                </metadata>
HEREDOC;
            }
            
            $products_str .= <<<HEREDOC

            <product>
                <id>$assetid</id>
                <name><![CDATA[{$details['name']}]]></name>
                <is_donation>$donation</is_donation>
                <quantity>$quantity</quantity>
                <item_price>$item_price</item_price>
                <total_item_price>$total_item_price</total_item_price>
                <item_price_incl_tax>$item_price_incl_tax</item_price_incl_tax>
                <total_item_price_incl_tax>$total_item_price_incl_tax</total_item_price_incl_tax>
                <item_tax>$tax_cost</item_tax>
                <total_item_tax>$total_item_tax</total_item_tax>$metadata_str
            </product>
HEREDOC;
        }
        
        //get total tax
        $total_tax = $this->getTotalTax($taxation_rate);
        $total_tax = $remove_tax ? sprintf('-'.$price_format, $total_tax) : sprintf($price_format, $total_tax);
        
        //get flat charges string
        $flat_charge_values_str = '';
        $flat_charges_total = 0.0;
        foreach ($flat_charges as $name => $price) {
            $flat_charge_values_str .= <<<HEREDOC

            <flat_charge>
                <name><![CDATA[$name]]></name>
                <price>$price</price>
            </flat_charge>
HEREDOC;
            $flat_charges_total += $price;
        }
        
        $flat_charges_str = '';
        if ($flat_charge_values_str != ''){
            $flat_charges_str = <<<HEREDOC

        <flat_charges>$flat_charge_values_str
        </flat_charges>
HEREDOC;
            
        }
        
        $flat_fees_total = sprintf($price_format, $flat_charges_total);

        $sub_total = sprintf($price_format, $this->getTotal(0, $taxation_rate));

        $grand_total_ex_delivery = $this->getGrandTotalExDelivery($taxation_rate, $remove_tax, $flat_charges);
        $delivery_total = $this->getTotalDeliveryCosts($grand_total_ex_delivery);
        
        $grand_total = sprintf($price_format, $grand_total_ex_delivery + $delivery_total);
        $grand_total_ex_delivery = sprintf($price_format, $grand_total_ex_delivery);
        $delivery_total = sprintf($price_format, $delivery_total);
        
        $cart_xml = <<<HEREDOC
    <cart>
        <currency_symbol><![CDATA[$currency_symbol]]></currency_symbol>
        <sub_total>$sub_total</sub_total>
        <taxation_name><![CDATA[$taxation_name]]></taxation_name>
        <total_tax>$total_tax</total_tax>
        <flat_fees_total>$flat_fees_total</flat_fees_total>
        <delivery_total>$delivery_total</delivery_total>
        <grand_total_ex_delivery>$grand_total_ex_delivery</grand_total_ex_delivery>
        <grand_total>$grand_total</grand_total>
        <products>$products_str
        </products>$flat_charges_str
    </cart>
HEREDOC;
        
        return $cart_xml;

    }//end getCartXml()
    
    
    function validateCart()
    {
        if (empty($this->cart)) return;

        $asset_ids = array_keys($this->cart);
        $result = $GLOBALS['SQ_SYSTEM']->am->assetExists($asset_ids);

        // the array of existing assetids
        if (is_array($result)) {

            foreach ($asset_ids as $id) {
                if (!is_int(array_search($id, $result))) {
                    $this->removeItem($id);
                }
            }

        // false, one item doesn't exist.
        } else if (is_bool($result) && !$result) {
            $this->removeItem($id);
        }

    }//end validateCart()


}//end class


?>