Android - Integration with existing calendar and GPS tracking

I have a system developed in php + mysql, which is the daily agenda of my street technicians. I need to develop an android application that uses the same user and password as my calendar technicians. This application should show the day's agenda and agenda of the technician's week. When the technician arrives at the client, he should press a button to start the timing. At the end of the technical visit, my technician must complete a report on the service performed during the visit. You should also fill in the report, in another field, the issues (which will be saved separately from the report). In a field with a list previously entered in the database (imported from my sales system), the technician will describe the parts used in that visit (if necessary). More than one piece may be used. Once completed, the signature of the person in charge of the company will be requested, ending the visit. While this company employee signs on the mobile screen, the app will capture 3 to 5 photos automatically. Once the report is signed, the technician will mark the visit as terminated, with the date and time automatically recorded. Afterwards, the app should send the report (with start, end, report and signature time) and photos to the database (report and link photos to the database and photos to an FTP). Along with this, this app should run GPS tracking in the background. Only users marked as administrators will be able to view the location of technicians. If motion is detected, you should save the location in the database from minute to minute. If stopped, you should not save the location. Although obvious, it is good to make it clear;) The location history recorded in the database should be sent to the Mysql database every hour or when the administrator user makes the request through a button. The administrator user can pull a location history of all technicians, every day of the week. This history should be viewed in the form of a map (google maps), with the route shown on the screen. You can perform searches with date and time filters to know the total distance traveled by the technician. For GPS tracking, a Google API can be used.