Mobile application in Xamarin.Forms: Creating a chat

Chat application in [login to view URL]: The user enters the mobile application with their username and password, then selects an area from a list to start a chat, then the other person (who is the configured person of the area) also enters the application and can also select from a list of people and start a chat, then the user starts the chat with the person in the area. Consider the following: - If the user initiates a chat with an area and the person of the area is not in the application, then a notification should arrive to the cell phone of the person of the area to see that he has a pending chat, then enter the app or select the notification and start the chat with the person. - If the person in the area initiates a chat with a user from the list of users and the person is not in the application then a notification must arrive to the cell phone of the person of the area to see that he has a pending chat, then he enters the app or select the notification and start the chat with the user. - The mobile application must have 3 tabs: tab 1: List of chats already started with users, tab 2: List of users to select and start a chat, tab 3 - Login option and exit the application - Drop-down menu: Options Start, Exit. - All conversation should be recorded in database - All chat will be text only The application must be created with: - [login to view URL] MVVM - Web API with Asp.net Core 3.0 and token. - SQL Server database. - DO NOT USE ENTITYFRAMEWORK, only native SQL data provider