Reddit 4-second motor

/*
  Reddit - 4 second motor - v1.0
  19 November 2019

*/

int led1 = 2;
int led2 = 3;
int led3 = 4;
int motorPin = 9;

int motor_state = 0;
long motor_run_time = 4000; // This is the time in milliseconds that you want the motor to run for.
unsigned long motor_run_begin_time = 0;
unsigned long motor_run_current_time = 0;


void setup() {
  Serial.begin(9600);
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(motorPin, OUTPUT);
  delay(5000);
  digitalWrite(led1, HIGH);
  digitalWrite(motorPin, HIGH);
  motor_run_begin_time = millis();
  Serial.println("Motor timer starting.");
  Serial.println("Exiting setup()");
}


void loop() {
  switch (motor_state) {
    case 0:
      check_motor_timer();
      break;
    case 1:
      turn_motor_off();
      break;
    case 2:
      // Nothing is in here!
      // If you wanted something to happen after the motor shut off,
      //   you could put the trigger for that in here.
      break;
  }
}


void check_motor_timer() {
  motor_run_current_time = millis();
  if (motor_run_current_time >= (motor_run_begin_time + motor_run_time)) {
    motor_state = 1;
  }
}


void turn_motor_off() {
  Serial.println("Motor shutting off.");
  digitalWrite(motorPin, LOW);
  motor_state = 2;
}


// ~~~~~~~~~ end ~~~~~~~~~~