I'm trying to implement chat for my webapp with following features:
- When user logs in he should see a number of unread messages (which is both offline messages and "unseen", I will explain "unseen" in next step).
- When user is anywhere in the app but on chat window he should be notified that he has a new message. Message should be marked "unseen" and must be added to the count of unread messages.
The first point is quite easily achieved using XEP-0013: Flexible Offline Message Retrieval. So I can retrieve offline messages and when I'm sure user has seen them - I remove them from unread list. But the problem is: how do I achieve same thing for "unseen" messages?
In short what I need is: any message should be marked as offline, unless user sees it and it's removed from the list by explicit request.
Can I achieve that with XMPP and how do I do that?
Thanks in advance.