angular application with healthshare authentication

I have an angular UI communicating with a iris rest api. Now I need to authenticate (to federated) before accessing the UI, and for a better solution  as the users are using the healthshare clinical viewer 2023, find a way to use the clinical viewer authentication / user to go to the UI.

The angular way would be to do an angular guard and have a function 'am I authenticate to federated', but I never found a function like this and how to get my username.

At the other end, creating a csp page in my csp folder that is either
- a csp including the angular html page outside the csp folder and passing in the header of the csp page,  the $usename
- or renaming my angular index.html page index.csp (not sure how to have the $username there)
Both solutions are more or less working. But I have problems with angular routing, refresh.... Do I need to give up of angular routing and call index.csp?route?

I will appreciate any help and experience.