Frontend: Allow specifying multiple lights for a light card

[balloob]

The request

_This could work for other places in Lovelace too, especially entity rows would be great for this, but let's start small!_

I would like to be able to have a light card control multiple lights. The light card should work as a virtual group that is frontend only. If any light is on: show light card as on. Don't try to mangle the colors, just normal yellow. If all cards are off, show icon as off. If any light is on, tapping it will turn all off.

The alternatives

Group in YAML.

Additional information

[iantrich]

Additional alternative is the actual light group.

You'll also have to contend with what to show for more-info

[balloob]

MVP will be no more info.

[SeanPM5]

Perhaps my idea in #4242 (which wasn't possible due to missing backend info) could be implemented in a different way here. If the card contains more than one entity (and the user hasn't specified an icon override yet), change the icon to mdi:lightbulb-multiple. Would make it a little more clear that it's controlling multiple lights.

[iantrich]

How should we display brightness? Should one light be the master for current value? It is not guaranteed that they will all have the same value let alone even support brightness

[bramkragten]

The same as Light group I guess?
It seems to use the mean.
https://github.com/home-assistant/home-assistant/blob/30249d14282eec04356da8a335f5478a66d0dfa5/homeassistant/components/group/light.py#L332

[balloob]

For implementation, implement a getInfo function that normalizes the info from 1 or multiple bulbs into an object that contains brightness, color etc.

[balloob]

We use light groups instead.

[iantrich]

@balloob anyone working on light group helpers like inputs?

[balloob]

Not yet.