#include <Servo.h>
#include <LiquidCrystal.h>

Servo myServo;

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

const int trigPin1 = 9;
const int echoPin1 = 10;
const int trigPin2 = 7;
const int echoPin2 = 8;
const int trigPin3 = 6;
const int echoPin3 = A0;

const int redLED = A1;
const int greenLED = A2;

long duration1, distance1;
long duration2, distance2;
long duration3, distance3;

int maxCapacity = 3;
int currentCapacity = 0;

void setup() {

  myServo.attach(13);
  myServo.write(0);  

 
  lcd.begin(16, 2);

 
  pinMode(trigPin1, OUTPUT);
  pinMode(echoPin1, INPUT);
  pinMode(trigPin2, OUTPUT);
  pinMode(echoPin2, INPUT);
  pinMode(trigPin3, OUTPUT);
  pinMode(echoPin3, INPUT);

 
  pinMode(redLED, OUTPUT);
  pinMode(greenLED, OUTPUT);

 
  lcd.print("Parking System");
  delay(2000);
  lcd.clear();
  lcd.print("2347131");
  delay(2000);
  lcd.clear();
}

void loop() {

  distance1 = readDistance(trigPin1, echoPin1);
  distance2 = readDistance(trigPin2, echoPin2);
  distance3 = readDistance(trigPin3, echoPin3);


  if (distance1 < 20 && currentCapacity < maxCapacity) {
    currentCapacity++;
    myServo.write(90);  
    delay(2000);
    myServo.write(0);  
    lcd.clear();
    lcd.print("Car Entered");
    delay(1000);
  }

 
  if (distance2 < 20 && currentCapacity > 0) {
    currentCapacity--;
    myServo.write(90); 
    delay(2000);
    myServo.write(0);  
    lcd.clear();
    lcd.print("Car Left");
    delay(1000);
  }

  // Update LED status
  if (currentCapacity == maxCapacity) {
    digitalWrite(redLED, HIGH);
    digitalWrite(greenLED, LOW);
    lcd.clear();
    lcd.print("Parking Full");
  } else {
    digitalWrite(redLED, LOW);
    digitalWrite(greenLED, HIGH);
    lcd.clear();
    lcd.print("Slots: ");
    lcd.print(maxCapacity - currentCapacity);
  }

  delay(500);
}

long readDistance(int trigPin, int echoPin) {

  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

 
  long duration = pulseIn(echoPin, HIGH);

  
  long distance = (duration / 2) / 29.1;
  return distance;
}