Rule screen should draw placeholder for invalid missing things

[dhylands]

I had to reboot my WifiAccess Point and my Sonos speakers got different IP addresses.

Which means I could no longer control them. So I had to remove and re-add each speaker.

This in turn invalidated all the rules which referenced the speaker.

When I went to edit the rules, the old speaker things were completely gone, so I needed to remember which speakers were used as inputs (so I could tell if they were currently playing or not) and which ones were used as outputs.

It would be better if the invalid thing were still visible somehow to act a reminder of what was invalid.

[mrstegeman]

@freaktechnik Tangentially related... are the Sonos speakers assigned IDs based on their IP addresses?

[dhylands]

The ID is the IP address.

[freaktechnik]

Yup, see https://github.com/freaktechnik/sonos-adapter/issues/5

[hobinjk]

The rules engine keeps enough information around to draw a barebones UI element. I could also allow it to store/create invalid rules. It should be relatively straightforward