/**
* Construct a cart key based on the billing schedule of a subscription product.
*
* Subscriptions groups products by billing schedule when calculating cart totals, so that shipping and other "per order" amounts
* can be calculated for each group of items for each renewal. This method constructs a cart key based on the billing schedule
* to allow products on the same billing schedule to be grouped together - free trials and synchronisation is accounted for by
* using the first renewal date (if any) for the susbcription.
*
* @since 2.0
*/
public static function get_recurring_cart_key($cart_item, $renewal_time = '')
{
$cart_key = '';
$product = $cart_item['data'];
$product_id = !empty($product->variation_id) ? $product->variation_id : $product->id;
$renewal_time = !empty($renewal_time) ? $renewal_time : WC_Subscriptions_Product::get_first_renewal_payment_time($product_id);
$interval = WC_Subscriptions_Product::get_interval($product);
$period = WC_Subscriptions_Product::get_period($product);
$length = WC_Subscriptions_Product::get_length($product);
$trial_period = WC_Subscriptions_Product::get_trial_period($product);
$trial_length = WC_Subscriptions_Product::get_trial_length($product);
if ($renewal_time > 0) {
$cart_key .= date('Y_m_d_', $renewal_time);
}
// First start with the billing interval and period
switch ($interval) {
case 1:
if ('day' == $period) {
$cart_key .= 'daily';
// always gotta be one exception
} else {
$cart_key .= sprintf('%sly', $period);
}
break;
case 2:
$cart_key .= sprintf('every_2nd_%s', $period);
break;
case 3:
$cart_key .= sprintf('every_3rd_%s', $period);
// or sometimes two exceptions it would seem
break;
default:
$cart_key .= sprintf('every_%dth_%s', $interval, $period);
break;
}
if ($length > 0) {
$cart_key .= '_for_';
$cart_key .= sprintf('%d_%s', $length, $period);
if ($length > 1) {
$cart_key .= 's';
}
}
if ($trial_length > 0) {
$cart_key .= sprintf('_after_a_%d_%s_trial', $trial_length, $trial_period);
}
return apply_filters('woocommerce_subscriptions_recurring_cart_key', $cart_key, $cart_item);
}
