99 Infiniti I30 car is hard to crank what could this be?

hi i have a 99 infiniti i30 and lately its been acting like it doesnt wanna crank. ill turn the key but nothing happens its doesnt make a sound or nothing. sometimes i have to sit there for a minute turning the key then it will eventually crank. most of the time it does it when its really hot outside, but when its cool like early in the morning or late at night it cranks right up. recently i was driving then i came to a stop and the car cut off. i tried cranking it over and over and every time it would crank then cut right back off. then i pushed it in the shade and it crunk right up. what could this be