Archive-Link ChatListItem should get some kind of chat changed event when its unread counter should change

[Simon-Laux]

the archive link pseudo chat list item now has an unread count, this unread count should have event for when it needs to be updated. otherwise desktop won't update it, or with a workaround it will update it too often (if it refetches the item on every incoming message event).

I propose that we emit the ChatChanged event for chatid 6 (DC_CHAT_ID_ARCHIVED_LINK), when we have an incoming message in a muted, archived chat. Ideal only if we did not already had an unread message in that chat, as the unread count on the archive link is not the count of messages, but of chats that have unread messages.

[r10s]

maybe MsgsChanged with chatId=DC_CHAT_ID_ARCHIVED_LINK and msgId=0 fits better as this is also the event where usually the other counters are updated.

(ChatChanged is about group name, image memberlist, however, if better fitting in desktop somehow, of course, we can also document that explicitly for the archived-link - or even create an explicit event for the archived-link)

[Simon-Laux]

Do what works best, MsgsChanged event is also fine, I'm working on a pr that adds events specifically for chatlist updates (which I'm planning to migrate desktop to), so as soon as there is logic for emitting any event (with chat id= DC_CHAT_ID_ARCHIVED_LINK) in this case it's sufficient for me, because adding another event using the same data in my new pr is trivial.

[r10s]

[...] or with a workaround it will update it too often (if it refetches the item on every incoming message event).

just stumbled upon that: it could have been smarter even without #3950, however, i also forgot about the the relatively new DC_EVENT_INCOMING_MSG_BUNCH, that would probably also have been "good enough".

however with #3950 things are better than "good enough" :)

imu, however, for a decreasing counter, you still have to listen to DC_EVENT_MSGS_NOTICED, ignoring the chat-id.