--
-- ec_reinst_gift_cert_on_order/1
--
create or replace function ec_reinst_gift_cert_on_order(
  integer
) returns int4 as $$

DECLARE
	v_order_id	alias for $1;
BEGIN
        insert into ec_gift_certificate_usage
        (gift_certificate_id, order_id, amount_reinstated, reinstated_date)
        select gift_certificate_id, v_order_id, coalesce(sum(amount_used),0)-coalesce(sum(amount_reinstated),0), now()
        from ec_gift_certificate_usage
        where order_id=v_order_id
        group by gift_certificate_id;

	return 0;
END;$$ language plpgsql;