Contract until summer 2020 at the moment I think so next summer he'd still be at optimum sale value.
However, I suspect he'll sign a new deal. So much is going right for him here at the moment but I still don't see any of the big six coming in for him so his best bet is to engineer the best deal possible at AFCB.
These things often take time and maybe even longer this time since his role not just in the team but in the PL as a whole has changed significantly this last 12 months. He's now recognised as a genuine regular threat to all teams and he'll want a contract that reflects that.
He'll want to be among the top earners at the club and, if I'm honest, I'd say he deserves to be. Whether he gets it or not is another matter.
Depending on how negotiations go, expect him to sign at some point in the next six weeks.