Building WiFi Login Control

In malls free WiFi is offered to visitors, we need to design a web-page where whenever the user connect to the mall's WiFi he will be directed to it. This page will ask him for a username and a password. When the user enters the right username and password he is forwarded to accept the terms and conditions. After acceptance of terms and conditions, the user will be directed to another page that contain offers where he will have to finish one of those offers to be able to finally access the free internet. Important Notes: 1. Those offers can be watching videos, visiting a shop and when he visit that shop he will be given an access code to enter to the page to proof he went there, buying an item from a shop and then he will be given an access code to enter to the page to proof he bought the item, etc... 2. There must be an admin panel where the administrator will put the offers that the user can finish in order to access the internet. 3. The page must be compatible with laptops, mobile phones, etc...