Need help with wiring Starlight headliner

I recently purchased a starlight headliner kit. On the end of the wires they provide a cigarette port attachment. That I don’t want to use. I want in the interior a toggle on and off switch that turns the roof lights on or off. I’m not sure what to purchase or how to wire it. The lights are 12v. I don’t want to get power from the battery directly because that’s a pain. I was thinking make to tap into the headlights power. So when the headlights are on, the switch is activated therefore I can toggle on and off my headliner lights. I’m not really sure what to do any help would be great!