need update FLUTTER app (we have the source code)

Hi. we need is a shall app that will give us the functionality that we need from the phone.
There are no screens on your end only functions that we can call.
i can give the source code for our app we need to update it
I will send the function 2 values:
1. the URL for the server with the API
2. The interval that the data needs to be send.
The URL is deferent for each app
Look at this doc.
this are all the functions we need and explanations:

Need to be a global param that can be changed for the root domain (serverUrl)
Need to be a global param for the name of the app (appName)

The global params need to be accessible from inside the app separate from the main code, in a separate file !

stop_transmission()
Close waze and Stop GPS


waze(string address)
Open waze with address that will be send


tel(string phone_number)
Open phone to call with the number that was send


sms(string phone_number, string message)
Send SMS to the number that was send with the message that was send


timeTransmissionInterval(string url, int timeInterval)
Will send GEO coordinates to selected url with date_time
every X seconds (time in seconds = timeInterval)
String dateStr = DateTime.now().toString();
Send a json ('longtitude': lng,'latitude': lat,'happened_at': dateStr, 'user_id': XXX)


logout(string url)
log out from the app and go to the login page.
Default url = “/home/index”


isGpsWorking()
Return true / false if GPS is enabled.
If GPS not in coverage area (no connection) return false


getCoordinates()
Return json GEO coordinates ('longtitude': lng,'latitude': lat) for the current location


saveLogin(string username, string password)
Save the username and password on the user phone


getLoginData()
Return json of username and password


deleteLoginData()
Delete the username and password from the user phone


enableCamera()
Allow to access the camera to take photos
GoBack()
On clicking on back icon on the phone call GoBack function on js