Wht Parts should i fix?? HELP ASAP PLZ!

So I bought my iphone 5s and it was water damaged when purchased. i pressed the power button the apple logo appeared then the screen turned black and unresponsive. It was still doing the boot then black thing with the hard reboot as well. i then connected to itunes and tried restoring and it went halfway and said error -1. i then changed the battery tried hard reboot put it in rice and still wouldnt turn on. i really want this phone to turn on bc its 64gigs and gold iphone 5s. PLZ HELP!!! which parts should i fix??? plz tell me ASAP