Customer Loyalty/Rewards program

I would like to have a web interface e.g. PHP to build a Customer Loyalty/Rewards (Points) program, Its going to read from an already existing system's database, hence, I'm going to provide an SQL view (MS SQL server 2008) with customer bills with the following fields ( Payment Date, Customer Name, Customer Mobile, Customer ID) The built system should support reading from 3 different Databases because we have 3 different branches, customers will have a unique id between all 3 branches The ID is basically is the national ID which consists of 10 digits. Would like the program to provide an API when given a customer id or a mobile number to return the total number of points as of the current moment. Developer should come up with his idea's on such lolalty program, however some ideas are : 1. there should be a user defined formula with a date range to calculate for each dollar spent, how many points the customer receives 2. Should be able to define special date ranges (special offers) where the points are doubled for example.. 3. Join Date 4. Define Points Expiry period.. 5. Add Customer Categorizes for example : Regular Customer: is any new customer Silver, gold, diamond, Customer : spent more than a certain amount in the previous year 6. Allow the addition of VIP Customers that have a constant special rate with unlimited time period. Developer should come up with his own ideas to improve this system.