ANCS Support

[cyberneel]

This PR Adds support for the Apple Notification Center Service (ANCS). It shows the Title and Subtitles as "Title - Subtitle" and the message is shown in the body of the InfiniTime notification. Accepting and Declining calls also worked.

The only "issue" right now is that you have to ReConnect after the first pair for ANCS discovery to go well. Maybe there is a way in the NimBLE stack to trigger ANCS Discovery after pairing change? Also, sometimes ANCS goes dormant and then works again. I think this could either be iOS throttling or

"ANCS is not guaranteed to always be present. As a result, the NC should look for and subscribe to the Service Changed characteristic of the GATT service in order to monitor for the potential publishing and unpublishing of the ANCS at any time."

[github-actions]

Build size and comparison to main:

Section	Size	Difference
text	381524B	8580B
data	948B	0B
bss	22720B	184B

[liamcharger]

For reference, closes #910

Instructions: since an encrypted connection is required before ANCS is available, you’ll need to disconnect your watch from your companion app after updating, then reconnect. You’ll get a passkey on your watch to enter into the dialog on your iPhone. After bonding, toggle off and on your iPhone’s Bluetooth, then tap InfiniTime in the list of bonded devices. Finally, you’ll get an alert asking you to allow your watch to read notifications. Click allow, and now you should start receiving notifications!

Something to note: as of now, since using ANCS creates a connection through iOS directly instead of through the companion app, the app will not be able to reconnect to InfiniTime without removing the bond, which results in ANCS being disabled until the steps above are repeated. We’re working on fixing this ;)

Update: this is fixed in the latest InfiniLink commit on the rebuild branch

[minacode]

typo

[liamcharger]

Fixed

[mark9064]

Does this implement subscribing to service changes? I think this is probably required given the ANCS can come and go at any time

I think the implementation of this is relatively simple, subscribe to the generic attribute service changed characteristic, and any time an indication is received service discovery should be performed again

[cyberneel]

@mark9064 I didn't explicitly implement the service changed part, but in all my testing the watch was always able to recover from a disconnect and showed new notifications. So maybe there is something in the stack that handles this?