#include <ESP32Servo.h>
#include <Stepper.h>

#define SL 12
#define SR 13
#define PTN 2
#define BTN 15
#define STEP 16
#define DIR 4
#define ECO 14
#define TRG 27
Servo servoL;
Servo servoR;
int speed = 100;
const int stepsPerRevolution = 200;
Stepper myStepper(stepsPerRevolution, DIR, STEP);

void setup() {
  // put your setup code here, to run once:
  pinMode(SR, OUTPUT);
  pinMode(SL, OUTPUT);
  pinMode(STEP, OUTPUT);
  pinMode(TRG, OUTPUT);
  pinMode(ECO, INPUT);
  pinMode(DIR, OUTPUT);
  pinMode(PTN, INPUT);
  pinMode(BTN, INPUT_PULLUP);
  servoR.attach(SR);
  servoL.attach(SL);
  myStepper.setSpeed(speed);
  Serial.begin(115200);
  Serial.print(speed);
  Serial.println(" km/hr.");
}

void loop() {

  int potenValue = analogRead(PTN);
  int degree = map(potenValue, 0, 4095, 0 , 180);
  servoL.write(degree);
  servoR.write(degree);

  digitalWrite(TRG, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRG, LOW);
  int duration = pulseIn(ECO, HIGH);
  int distance = duration / 58;
  if (distance < 30 && speed > 0) {

    for (speed; speed > 0; speed--) {
      myStepper.setSpeed(speed);
      myStepper.step(2);
      Serial.print(speed);
      Serial.println(" km/hr.");
    }
    Serial.print(speed);
    Serial.println(" km/hr.");  
  } else if(distance >= 30) {
    if(speed < 100) {
      for (speed = 1; speed <= 100; speed++) {
        myStepper.setSpeed(speed);
        myStepper.step(2);
        Serial.print(speed);
        Serial.println(" km/hr.");            
      }
    }
  }
  if (speed > 0) {
    myStepper.step(10);
  }      
   
  int buttonValue = digitalRead(BTN); 
  if (buttonValue == 0) {
    Serial.print(0);
    Serial.println(" km/hr.");
    while (digitalRead(BTN)== 0) {}
    for (int s = 1; s <= speed; s++) {
      myStepper.setSpeed(s);
      myStepper.step(1);
      Serial.print(s);
      Serial.println(" km/hr.");
    }
  }  
}