Developing a mobile application is required

The services of a mobile application developer are required. You need to develop a mobile application that functionally duplicates the existing online store. Classic. Make it a small user account - login by name and phone number, where he could track his orders and statuses of their execution. The application, of course, will work directly with the store database, offline, use the stored data. Implement the ability to send messages to users of the application. These will be Novelty of goods, Promotions, Congratulations for the holiday, etc. It is also a feedback form where users can ask questions and get answers. In the process, you may have to make small improvements to the store itself to make it friends with the application. OpenCart store. I don’t know the prices and specifics of these works, so I am waiting for your suggestions. Payment by default.
It is desirable to get source materials together with the work done, so that later it is possible to make small changes and finishes on your own. In theory, at least that possibility