How to control 12v dc motor (peristaltic pump) using function

General
4

So i have make the simple one, and this is the arduino code

int ml;
int nyala;
int input;
int dc_pin = D1;

void setup() {
  pinMode(dc_pin, OUTPUT);
  Serial.begin(115200);
}
  
void loop() {
  input = Serial.parseInt();
  ml = input/10;
  nyala = ml * 500;

  if(nyala == 500){
    digitalWrite(dc_pin, LOW);
  delay(500);
  MotorStop();
  }
  else if(nyala == 1000){
    digitalWrite(dc_pin, LOW);
  delay(1000);
  MotorStop();
  }
  else if(nyala == 2000){
    digitalWrite(dc_pin, LOW);
  delay(2000);
  MotorStop();
  }
}

void MotorStop(){
  digitalWrite(dc_pin, LOW);
  digitalWrite(dc_pin, LOW);
}

The ml is the formula to calculate how many liquid must use following the input.
And nyala is how long the peristaltic pump have to turn on.