Two white, two black, two ground, and red wire in ceiling box connected to switch
From your photo, it's clear the electrician left you a handy little gift -- those third white and bare wires are pre-installed pigtails.  With the power to the circuit off of course, simply strip the white pigtail and the unstripped black wire and hook up your receptacle (free black wire to brass screw, white pigtail wire to silver screw, bare pigtail to green screw).