Download script modification

I currently has a working download which limit how many movies that a member can download. The script currently allow member to download 10 movies for their first month membership, and it will increase 10 more movies for their 2nd membership and so on, the max number of movies they can download is 40, no matter how long they have been member. All the above figures can be define in the script. But I would like to change it a little bite. I would like to add one more variable to the script called "unlimited download". If I define unlimited download = na, it means it will not affect the current operation of the script. The script will just follow the old way of working. If I define unlimited download = 0, it means they can have unlimited download once they become member. If I define unlimited download = 1 it means user will have unlimited download of movies after their first month membership, they can download 10 movies during their first month memership. If I define unlimited download = 2 it means user will have unlimited download of movies after their 2nd month membership, during their 2nd month, they can download 20 movies (becasue 10 movies for the first month and increase 10 more for the second) and so on.... ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Complete ownership and distribution copyrights to all work purchased. ## Platform linux