/* 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();

	$restrictedItems = getcollection(123456789); //enter your collectionid (to get the collectionid, goto your Shopify admin > products > collections > click on the collection > read the numbers off the end of the URL)
	$freeShippingThreshold = 150; //this is before discounts

	$containsRestricted = false;
	$t = 0;
	foreach ($DATA['items'] as $item) {
		if (in_array($item['product_id'],$restrictedItems)) $containsRestricted = true;
		$t += $item['quantity']*$item['price']/100;
	}

	if (!$containsRestricted && $t > $freeShippingThreshold) {
		$_RATES[] = array(
			"service_name" => "Free Shipping", //this is what the customer will see
			"service_code" => "Free Shipping", //can be anything you like
			"total_price" => 0, //in cents
			"currency" => "USD",
		);
	}

	return $_RATES;

	/* do not edit below this line */

}