Find next upcomming date in report (calendar or list) with workflow

Find next upcomming date in report (calendar or list) with workflow

I have a web store in which I want to force the delivery date of the order to be the next upcomming date of another form (a form that states the available dates for deliveries). Any type of script like "getthenextdate" exist in Deluge ?

Also, is it possible in a date field to limit the entry for the next 2 weeks ? Say if I sell perishable product that might not be available in 3 weeks. I suppose I could make a script, but the customer would know only when submitting the form. I'd rather limit while tring to enter the field itself.

Sylvain