Send Automated Email W/ Coupon Code After Customer Purchases X

Hi,

We are trying to setup a promotion where if a customer purchases X they will receive an automated email with a coupon code (Single Use) for Y. I know you can pass coupon codes through an email marketing campaign, but is there a way to do this automated when a customer fulfills a requirement?

I thought about doing it through the saved search email function, but I wouldn't have a way of passing a single use coupon code. Thoughts?

Thank you.