Battery Hooked Up Wrong

Alright i had told my friend to hook up my batt to a charger he had hooked up the charger wrong and put positive to negative ect… now it will not start and not even enuff power to get lights… does anyone know if this could mess with anything but my batt? if so what should i look for b4 wasting money

Check ur main fuses under the hood. How long was batt. Charged?

Remove the battery and try charging it properly. Is the charger still operable? Same question, how long was it left to charge?