Advice on how to create/fulfill orders

-- HikaShop version -- : 2.6.4
-- Joomla version -- : 3.6.4

I sell customized stil files. What I want is for a customer to select the product they are interested in. They then select the configuration options. Generating the download file for them to purchase can take some time, so the finished product cannot be put in their cart right away. So I think the best way to proceed is to send them an email when their product is ready. The question is, how best to accomplish this? As a first step I created a configuration file which is written to a file which a cron task processes and creates the output file. But this leaves me with a finished file and no way to stuff it in the user's cart because the file was created 'offline'. What strikes me as the best solution would be for the offline process to put the customized file in the customer's cart and send them an email that their order is now ready for download, but there's no obvious way to do that.
So I'm just looking for some advice on what you think would be the best way to try and accomplish this task... or is this too complex for Hikashop?

figured out an easy way to do it. sorry to trouble you.