Discount Coupon System with Variable Discount for Multiple Items

Discount Coupon System with Variable Discount for Multiple Items We need someone who can write an Oscommerce script to implement a discount coupon system which can be set to be valid only for some or specific product. For example, we can generate a coupon code for discount of 30% on 1 product which is in the product database. If customer try to use this coupon code for other products, the system will not give any discount. The specifications needed: From Admin panel side: Need to have options for: -Creating coupon code with on/off button, we can disable/enable coupon code anytime -We can have the title of discount coupon. -Option for percentage price discount or manual deduction (i.e. 10% off, or -$50 off) -Option to apply coupon for all products, specific category, or specific product only. -If specific product: I.e. coupon code will only be valid for only 1 product only, which we can choose from product database. -if specific category: i.e. 10% discount on 1 product category, which we can choose from product database. -Option for expiry date (i.e. coupon only valid until 31/12/2008 etc.) -Option to set how many times the coupon can be used (i.e. coupon will be rendered invalid after it has been used for 20 times) -Multiple coupon tracker to check simple statistic for each coupon (i.e. Coupon 1 has been used 10 times, Coupon 2 has been used 2 time, etc) From customer side (during checkout process): -At checkout customer has option to enter coupon, and will display the deduction amount and the total amount as usual. After checkout is finalized, the coupon code used should be also stored in database so when we check their order, we know which coupon code was used before shipping their order. Note: There are many oscommerce scripts out there which has relation to coupon discount idea, although none of them has option to apply coupon only for 1 specific product/category. This would be a good place to start.