Android application for a point-of-sale system that matches the system available on our website.

Requirements and specifications: 1- The application must be compatible with the GS web application through synchronization with the same database, In Google Play, two applications are added, the first application is GS-POS and the second application GS-Restaurants is the same, with some advantages between them. 2-The application should work without needing the internet connection With a limit of the duration of the application to be used without sync and without the internet. 3-The application should support point of sale system Supports screen size 15.6 / 8 / 3.95 inch + screen with an 8 digital customer price display (customer price display - quick printing of the invoice when pressing the payment button - opening the cash drawer at the same time as printing the invoice) NFC card reader and Selling through network connectivity, With the difference between the two applications in the GS-Restaurants need to add a map of the restaurant tables, specify the ordering table, print copies of the invoice for the kitchen and the rest of the restaurant, different design of the printed invoice, and some other additions. 4- The application is controlled through a web application system.(Verify the accuracy of the login data by checking the account status/customer license/subscription expiry date/subscription type/How long the app allows you to use without syncing ) 5- All data is matched between the web application and the Android application through synchronization.(Add/Edit/Delete/Print Reports/Shortcut Settings....etc). 6-Sending system notifications and billing via app notifications and via WhatsApp / email... Taking into account the minor differences between the GS-POS & GS-RESTAURANT applications and everything else the system needs that was not mentioned in this request. Note: The application will be on the seller's device, so it must contain everything the seller needs from the web application system, and application management will be through the web application. Provide the complete source code files.