Replacing gfci and switch lost with wiring
OK.  So the zoom-in and brightening makes clear what is happening. Imagine there is a physical partition between left and right sides of the box.  

On the left side

Goes the GFCI.   Since you don't care about protecting any devices downline of here, this is super easy:  Leave the "For Wizards Only" warning tape on the LOAD terminals, and everything goes to LINE.  Almost all GFCI devices allow you to screw-to-clamp 2 wires under each screw.  

On the right side

This is a simple 1-way (as the Brits call it) switch.  2 black wires and you're done.  

You're welcome to use a 3-way switch, just make sure you put one of the wires on "common" (the black screw).