<?php
/* This macro will be parsed as PHP code (see http://www.php.net)

The calculateshipping function is called every time a shipping calculation request is made by Shopify.

The function must return an array of available shipping options, otherwise no shipping options will be returned to your customers.
*/
function calculateshipping($DATA) {

	/* do not edit above this line */

	$_RATES = array();

	//rate for each vendor (all prices in cents)
	$config = array(
		'VendorA' => array('rate'=>1000, 'sub'=>500),
		'VendorB' => array('rate'=>999, 'sub'=>500),
		'VendorC' => array('rate'=>1099, 'sub'=>500),
	);
	
	$defaultrate = 500;

	$rate = 0;
	//go through cart and group by type
	foreach ($DATA['items'] as $item) {
		if (isset($config[$item['vendor']])) {
			if ($item['quantity'] > 1) {
				$rate += $config[$item['vendor']]['rate'] + $config[$item['vendor']]['sub']*($item['quantity']-1);
			} else {
				$rate += $config[$item['vendor']]['rate'];
			}
		} else {
			//default rate
			$rate += $defaultrate*$item['quantity'];
		}
	}

	//round up nearest cent
	$rate = ceil($rate);

	$_RATES[] = array(
		"service_name" => "Standard Shipping",
		"service_code" => "STANDARD",
		"total_price" => $rate, //in cents
		"currency" => "USD",
	);

	return $_RATES;

	/* do not edit below this line */

}