aMember (site.php): change access period based on purchased quantity

site.php

<?php

/**
 * Change access period based on purchased quantity
 */

Am_Di::getInstance()->hook->add(Am_Event::ACCESS_BEFORE_INSERT, function(Am_Event $e) {
    $access = $e->getAccess();
    if ($access->invoice_item_id && $access->expire_date != Am_Period::MAX_SQL_DATE) {
        $item = $e->getDi()->invoiceItemTable->load($access->invoice_item_id);
        $p = new Am_Period($item->first_period);
        for ($i=1; $i<$item->qty; $i++) {
            $access->expire_date = $p->addTo($access->expire_date);
        }
    }
});