Daily Calorie Intake, how many should I be getting?

I'm 18, male, 168lbs.
Rugby player, but the season has now finished, so only exercise I do is dumbbell workouts throughout week, and one 30 min run a week.

Have used this app to lose weight, however I'm now at a comfortable level and wish to start working out and gaining muscle-mass. However I don't know what my daily calorie intake should now be? Should I be at a caloric surplus? Can anyone help me calculate a rough figure using the details above possibly?

Thanks in advance.