Codeignitor Point of sale system required.

Hello Freelancers, I would like to develop web based Point of sale system with Codeignitor which will be fully customization. 1. Multiple stores can be maintained. 2. Items can be specified to be sold across all the stores as well item can be specified to be sold for particular store. 3. Item can be grouped and can be sold in group as well as individually . 4. Discount Policy. 4.1 : Discount can be specified for particular item or on whole Bill 4.2 : Discount can be specified for customer also when we enter new customer. 4.3 : Same Customer can have different discount rate on different store. 5. Tax can be specified on Bill's being generated and each store can have it's own Tax Configuration. 6. When we create new customer should have option to specified that user is eligible for taxable bill or normal. 7. Configuration to Employee : admin can specify which module can be accessible by employee. And have many other Features which will be discussed with selected Freelancer.