#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <ESP32Servo.h>
#include <Keypad.h>

const int trigPin = 2;
const int echoPin = 4;
const int greenLEDPin = 16;
const int redLEDPin = 17;
const int buzzerPin = 18;
const int servoPin = 19;

LiquidCrystal_I2C lcd(0x27, 16, 2);
Servo gateServo;

const byte ROWS = 4;
const byte COLS = 4;
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {34, 35, 32, 33}; // Connect to the row pinouts of the keypad
byte colPins[COLS] = {25, 26, 27, 14}; // Connect to the column pinouts of the keypad

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

String password = "679";
String enteredPassword = "";
unsigned long startTime;
bool carInside = false;
bool carDetected = false;
const float costPerHour = 2.0;

void setup() {
  Serial.begin(115200);
  
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(greenLEDPin, OUTPUT);
  pinMode(redLEDPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  
  gateServo.attach(servoPin);
  gateServo.write(0); // Closed position
  
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Enter Password:");
}

void loop() {
  detectCar();
  
  if (!carDetected) {
    digitalWrite(greenLEDPin, HIGH);
    digitalWrite(redLEDPin, LOW);
    noTone(buzzerPin);
  } else {
    digitalWrite(greenLEDPin, LOW);
    digitalWrite(redLEDPin, HIGH);
    tone(buzzerPin, 1000);
  }
  
  char key = keypad.getKey();
  if (key) {
    if (key == '#') {
      if (enteredPassword == password) {
        if (carInside) {
          lcd.clear();
          lcd.setCursor(0, 0);
          lcd.print("Enter Amount:");
          float amountPaid = getAmountPaid();
          unsigned long endTime = millis();
          unsigned long totalHours = (endTime - startTime) / (1000 * 60 * 60);
          float totalCost = totalHours * costPerHour;
          if (amountPaid >= totalCost) {
            gateServo.write(90); // Open position
            delay(5000); // Keep gate open for 5 seconds
            gateServo.write(0); // Close position
            carInside = false;
            lcd.clear();
            lcd.setCursor(0, 0);
            lcd.print("Enter Password:");
          } else {
            lcd.clear();
            lcd.setCursor(0, 0);
            lcd.print("Insufficient Funds");
            delay(2000);
            lcd.clear();
            lcd.setCursor(0, 0);
            lcd.print("Enter Password:");
          }
        } else {
          gateServo.write(90); // Open position
          delay(5000); // Keep gate open for 5 seconds
          gateServo.write(0); // Close position
          startTime = millis();
          carInside = true;
          lcd.clear();
          lcd.setCursor(0, 0);
          lcd.print("Enter Password:");
        }
      } else {
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Wrong Password");
        delay(2000);
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Enter Password:");
      }
      enteredPassword = "";
    } else {
      enteredPassword += key;
      lcd.setCursor(0, 1);
      lcd.print(enteredPassword);
    }
  }
}

void detectCar() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  long duration = pulseIn(echoPin, HIGH);
  float distance = (duration * 0.034) / 2;
  
  if (distance < 10) {
    carDetected = true;
  } else {
    carDetected = false;
  }
}

float getAmountPaid() {
  String amountStr = "";
  lcd.setCursor(0, 1);
  lcd.print(amountStr);
  while (true) {
    char key = keypad.getKey();
    if (key) {
      if (key == '#') {
        return amountStr.toFloat();
      } else {
        amountStr += key;
        lcd.setCursor(0, 1);
        lcd.print(amountStr);
      }
    }
  }
}