Build a chat based doctor-client website

I want a website where 1) We have a list of approved doctors. They log in , create profiles etc. 2) Customers log in and see a default chat frame, this goes out to a scheduling bot. It asks basic questions and tells customers the doctors available (bot can be another human sales rep/ automated) 3) Once customer accepts a doctor, the doctor messages him directly and the two chat via messages and can upload files. 4) The message thread is stored against the customer and the doctor. I was planning to create this in MeteorJS but am open to other suggestions. Please bid by specifically mentioning the technology you will use , the estimated time and a brief architectural design (dbs, controllers/methods etc).