feature: Show reason push is not enabled, if that is the case

[gdt]

I recently installed the NC app "DAV Push", enabled it, and then tried to set up push to DAVx5 on my phone. I got it working after what felt like more fiddling than I should have had to do, but this discussion is about an enhancement that would have eased setup.

When in an account and seeing the list of calendars, one can tap a calendar. If DAVx5 has successfully registered for push, it shows an entry "Push support" and e.g. "Subscribed (9/16/24 15:37)". If it should be doing push but has not successfully registered, the entry is omitted.

For people trying to set up push, or who formerly had it working and suffering a failure/config error, it's hard to diagnose (without adb, but the logcat in debug zip didn't help).

The feature request is:

• Always show the "Push support" entry
• In the logic that tries to set up push, set a string based on the first failure in the chain, which e.g. could be one of
  • No UnifiedPush provider configured
  • Server responded [description] when queried about push support, perhaps translated into "server replied that push app is not installed" or "server denied permission for push" or whatever.
  • Failed to get push information from UP provider
  • Failed to set push information at server
  • (perhaps) After asking for a test push message, did not receive it.

I know other programs handle push differently, but I have seen an overall test flow that asks the server to send a push message and the user to click on an acknowledge button in the notification that's displayed when it arrives. Here, there's no user notification, so the e2e test could pass if the DAVx5 receives the test push message.

I realize parts of this might be a lot of work, but I am guessing that just writing a string at each "nope, not doing push on this calendar" point, and then not suppressing the entry is fairly easy. While people who might not care about push will see it, my guess is that people only look at this screen when having trouble.

Looking more, I see that on a disabled calendar, the entry reads "Server advertises Push support".

So it might be that what's needed is just "Server does not advertise Push support" in that case, and perhaps various error cases.

I can see suppressing the entry entirely if in global settings UP provider is not set. But I'd lean to including it and saying 'No UP provider configured."

For contacts, a "Push support for contacts is not implemented." would also help.