Create a Chat system which simulates a A.I. chatbot in website

Dear Freelancers, I want to create a simple chat system which consist in the following: Frontend: one landing page with a text box, which you can chat. Backend: The operators must access via backend and reply the users questions in real time. Important: 1. The whole system must give the appearance that it's a machine answering questions and not a human. 2. Admin must be able to create as many operators as needed. 3. All chat users requests must be splitted evenly among the operators. 4. Spell checking. 5. Admin must be able to specify the max number of total users interacting with the operators. 6. All conversations must remain in log. 7. Operators must be able to check IP of chat users. 8. One same IP cant request chat twice or more at the same time. Please let me know your best price and duration of development Thanks