Drupal Commerce

Good afternoon!
Help is needed to write a module or refine the code. There is a website built on commerce kickstart. The site sells digital content, implemented through a commerce file (here is an example of how it works Text hidden) at the moment everything works like this:
- the buyer is registered
- buys goods
- after payment, the file he can download from his profile (there is a tab "files")

It turns out that without registration, the file cannot be obtained. It is necessary that regardless of whether the user is registered or not, after payment he was given a window "Thank you for the purchase" in which the link to download the purchased file was displayed. Ideally, you need that when buying the user enters his email and in addition to the window "Thank you for the purchase"; he also the file and automatic was sold on soap.

If there are other options, I am ready to consider.

Cost and timeline required.