const int TRIG_PIN    = 19;
const int ECHO_PIN    = 21;
const int TRIG2_PIN   = 26;
const int ECHO2_PIN   = 27;
const int TRIG3_PIN   = 5;
const int ECHO3_PIN   = 4;
const int BUZZER_PIN  = 2;
// const int DISTANCE_THRESHOLD = 200; // no usage in this cod 
int activeSensor = 0;
/*
const float SPEED_OF_SOUND = 343.0; // Speed of sound in m/s
// arduino isn't calculator 
float distanceToCm(float duration) {
  // Calculate distance in centimeters
  return (duration * SPEED_OF_SOUND) / 20000.0;
}*/
float readUltrasonicSensor(int trigPin, int echoPin) {
  long duration;
  float dist;
  // Trigger ultrasonic sensor
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  //distance = distanceToCm(duration); // remove
  dist=duration/57 ; // 57 is getting this offer for me cm directly 
  return dist;
}
void beep(int times) {
  for (int i = 0; i < times; i++) {
    digitalWrite(BUZZER_PIN, HIGH);
    delay(200);
    digitalWrite(BUZZER_PIN, LOW);
    delay(200);
  }
}

void setup() {
  Serial.begin(9600);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(TRIG2_PIN, OUTPUT);
  pinMode(ECHO2_PIN, INPUT);
  pinMode(TRIG3_PIN, OUTPUT);
  pinMode(ECHO3_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
}

void loop() {
  // change the name of distance in float func to be dist only 
  float distance;
  // Read ultrasonic sensor 1
  distance = readUltrasonicSensor(TRIG_PIN, ECHO_PIN);
  if (distance <= 70 && activeSensor == 0) {
    Serial.print("dist0: ");
    Serial.println(distance);
    beep(2);
    activeSensor = 1;
  }

  // Read ultrasonic sensor 2
  distance = readUltrasonicSensor(TRIG2_PIN, ECHO2_PIN);
  if (distance <= 50 && activeSensor == 1) {
    Serial.print("dist1: ");
    Serial.println(distance);
    beep(4);
    activeSensor = 2;
  }

  // Read ultrasonic sensor 3
  distance = readUltrasonicSensor(TRIG3_PIN, ECHO3_PIN);
  if (distance <= 50 && activeSensor == 2) {
    Serial.print("dist2: ");
    Serial.println(distance);
    beep(6);
    activeSensor = 0; // Reset the active sensor to 0
  }
  delay(1000);
}