It's great that you do the library, and for the gui we already have at least two extensible platforms (pigdgin/libpurple and weechat) so you may consider adapti

It's great that you do the library, and for the gui we already have at least two extensible platforms (pigdgin/libpurple and weechat) so you may consider adapting to one of those, it also makes it easy to have one chat client for all needs.