Flip Flop T-> dont work

//SALIDAS
const int Q = 13;
const int Q_ =3;
//ENTRADAS
int button=8;
//VARIABLES AUX
int Q_pr =0;
int Q_nx =0;
int buttonState=0;
int enable=1;// la variable enable se asegura que solo se ejecute el Flip Flop una sola vez;

void setup() {
  // put your setup code here, to run once:
  pinMode(Q, OUTPUT);
  pinMode(Q_, OUTPUT);
  pinMode(button, INPUT);


}

void loop() {
  // put your main code here, to run repeatedly:
  buttonState = digitalRead(button);
  if (buttonState == HIGH && enable==1) {
    Q_nx=fft(1, Q_pr, Q, Q_);
    Q_pr = Q_nx;
    enable =0;
  }
  else if (buttonState == LOW) {
    enable =1;
  }
}

int fft(int T, int Q_pr, int Q, int Q_){
  if (T==1){
    if(Q_pr==1){
      digitalWrite(Q, LOW);
      digitalWrite(Q_, HIGH);
      delay(500);
      return 0;
    }
    if(Q_pr==0){
      digitalWrite(Q, HIGH);
      digitalWrite(Q_, LOW);
      delay(500);
      return 1;
    }
  }
  else if (T==0){
    return Q_pr;
  }
}