#include <ESP32Servo.h>

#define TRIG_PIN 23
#define ECHO_PIN 22
#define SERVO_PIN 26
#define DISTANCE_THRESHOLD 40

Servo servo;

float duration_us, distance_cm;
int door_position = 0; // 0 - closed, 1 - opened
int can_open = 1; // True/False
int can_close = 0; // True/False

void setup() {

  Serial.begin(9600);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  servo.attach(SERVO_PIN);
  servo.write(90);

  // put your setup code here, to run once:
  //Serial.begin(115200);
  //Serial.println("Hello, ESP32!");
}

void loop() {

  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  
  duration_us = pulseIn(ECHO_PIN, HIGH);
  distance_cm = 0.017 * duration_us;

  if (distance_cm != 0.00 && distance_cm < DISTANCE_THRESHOLD && can_open == 1 && door_position == 0) {
    servo.write(0); // to open
    door_position = 1;
    can_open = 0;
  }

  if (distance_cm > DISTANCE_THRESHOLD && door_position == 1) {
    can_close = 1;
  }

  if (can_close == 1 && door_position == 1 && distance_cm < DISTANCE_THRESHOLD) {
    delay(1000);
    servo.write(90); // to close
    door_position = 0;
    can_open = 1;
    can_close = 0;
    delay(3000);
  }
  
  // //servo.write(90);
  //if else {
  //  is_open = 0;
    //servo.write(0);
  //}

  Serial.print(door_position);
  Serial.print(can_open);
  Serial.print(can_close);
  
  Serial.print("distance: ");
  Serial.print(distance_cm);
  Serial.print(" cm \n");

  delay(500);
}