Phone state sensor

[ludeeus]

I'm not sure if this has been requested in the past, I could not find any discussions about it going by the titles at least.

The Android app exposes a phone state sensor to show which state the phone function/app is in, that sensor account for 50% of my current automations and it would be great if this was exposed with the iOS app as well.
Docs: https://companion.home-assistant.io/docs/core/sensors#phone-state-sensor

[bgoncal]

I remember I researched this a while back but wasn't possible to do it reliably in background without turning our app a "phone app", I'll leave 2 links here for when I have more time to look into it (or if someone else wants to jump in):

https://developer.apple.com/documentation/CallKit
https://developer.apple.com/documentation/coretelephony/ctcallcenter#//apple_ref/occ/cl/CTCallCenter