1990 Mazda RX7 Car was idiling rough no will not start

Have mazda rx7 and the other day it started idiling rough jumping from 1000rpm to about 2000rpm up and down no stop. During this time it all so made my convertible top not motor up or down or the ac fan not to blow like the car was shutting only certain things off. It did this then I shut car off then restarted and it continued then all of a sudden the idiling smoothed out and the electrical started working all again. Now this afternoon the next day car will not even attempt to start just clicks once with electrical drown down then nothing. I tested battery and is fully charged but car will just do nothing but all eletrical is still operating.