#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <HX711.h>
#include <Servo.h>

LiquidCrystal_I2C lcd(0x3F, 16, 2);  // Address may vary; use an I2C scanner to find the correct address.
HX711 scale;

Servo barrierServo;

const int pirStartPin = 2;    // PIR motion sensor for starting
const int pirStopPin = 3;     // PIR motion sensor for stopping
const int servoPin = 9;       // Servo control pin
const int ledPin = 13;        // Built-in LED for status indication

const int LOADCELL_DOUT_PIN = 11;  // Pin for HX711 data output
const int LOADCELL_SCK_PIN = 12;   // Pin for HX711 serial clock

const long minimumWeight = 1000;  // Minimum weight in grams (1kg)
const long maximumWeight = 5000;  // Maximum weight in grams (5kg)

bool barrierOpen = false;

void setup() {
  pinMode(pirStartPin, INPUT);
  pinMode(pirStopPin, INPUT);
  pinMode(ledPin, OUTPUT);

  lcd.init();
  lcd.backlight();  // Keep the backlight on initially

  // Add contrast adjustment instructions
  Serial.println("Adjust the LCD contrast manually using the potentiometer on the LCD module.");
  Serial.println("Turn the potentiometer until the text is clearly visible.");

  scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);
  scale.set_scale();  // Set this to your own calibration factor.

  barrierServo.attach(servoPin);
  closeBarrier();

  Serial.begin(9600);
}

void loop() {
  bool carDetected = false;

  if (digitalRead(pirStartPin) == HIGH) {
    carDetected = true;
    openBarrier();
  }

  if (digitalRead(pirStopPin) == HIGH) {
    carDetected = false;
    closeBarrier();
  }

  // Read the potentiometer value to control LCD backlight
  int potValue = analogRead(A0);  // Read the potentiometer value
  int backlightValue = map(potValue, 0, 1023, 0, 255);  // Map it to LCD backlight range (0-255)
  lcd.setBacklight(backlightValue);  // Set the LCD backlight based on potentiometer value

  if (carDetected) {
    long weight = getWeight();
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Weight: ");
    lcd.print(weight);
    lcd.print("g");

    if (weight > maximumWeight) {
      lcd.setCursor(0, 2);
      lcd.print("Turn back or");
      lcd.setCursor(0, 3);
      lcd.print("Reduce weight");
      closeBarrier();
    }
  } else {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Weightbridge");
  }
}

void openBarrier() {
  barrierServo.write(0);  // Open the barrier
  barrierOpen = true;
  digitalWrite(ledPin, HIGH);
}

void closeBarrier() {
  barrierServo.write(90);  // Close the barrier
  barrierOpen = false;
  digitalWrite(ledPin, LOW);
}

long getWeight() {
  return scale.get_units(10);  // Read the weight from the load cell
}