Short circuiting electrical system - '79 323

I was replacing a dead battery and I must have got the polarity wrong because when attching the negative terminal sparks went flying and I definitely fizzled some of the wiring to my front headlights. That was the only visually noticable connection but I'm just wondering how much of my electrical system is hosed? Would the damage have been extensive?

It's not turning over at present

Thanks for any help

Ashley