Precondition: The user has not yet authenticated against Keycloak.
Main success scenario:
The user enters their login credentials and Keycloak successfully authenticates them.
Alternatively, they go to a permalink for their user or map, where no login is needed.
Alternative scenario:
The user enters incorrect login credentials.
In this case, the app displays an error message to the user indicating that the login failed.
Error scenario:
There is an error in the app's authentication process.
In this case, the app displays an error message to the user and tells them to try again.
Postcondition:
The user is authenticated and has access to the PermaplanT app.
The user is authenticated and has access to Nextcloud.
Non-functional Constraints:
The login process must be secure to protect the user's personal information.
The app must clearly communicate to the user whether the login was successful or not.