Dynamic Coupon Codes after Facebooking or Tweeting

so here's what i want to do. Right now i have an OScommerce site. This is what I want to have happen. Upon completing an order, a customer is given the chance to get 5% off their next order if they tweet or facebook our site...when they do it, they are sent to a page that generated a coupon code JUST FOR THEM....i dont want this to be where anyone can enter it. It also needs to be a 1 time only thing, where once a customer uses the coupon code, they can no longer use it again. However they can get another 5% off coupon code after completing another order, again, if they tweet or facebook a message of my choosing (i want to be able to manually edit this somewhere in my admin section). i also want to be able to email blast my entire client list (only of customers who have purchased in the past) with this opportunity as well 1 time to launch it.