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

// Initialize LCD (address: 0x27, 16 cols, 2 rows)
LiquidCrystal_I2C lcd(0x27, 16, 2);

class BMI {
  private:
    float weight; // in kilograms
    float height; // in meters

  public:
    BMI(float w, float h) : weight(w), height(h) {}

    float calculateBMI() {
      return weight / (height * height);
    }

    void displayBMI(float bmi) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("BMI: ");
      lcd.print(bmi, 2); // Print BMI with 2 decimal places

      lcd.setCursor(0, 1);
      if (bmi < 18.5) {
        lcd.print("Underweight");
      } else if (bmi >= 18.5 && bmi < 24.9) {
        lcd.print("Normal");
      } else if (bmi >= 25 && bmi < 29.9) {
        lcd.print("Overweight");
      } else {
        lcd.print("Obese");
      }
    }
};

// Ultrasonic sensor pins
const int trigPin = 7;
const int echoPin = 6;

void setup() {
  Serial.begin(9600);
  Serial.println("Program started."); // Add this for debugging

  lcd.begin(16, 2); // Initialize LCD with 16 columns and 2 rows
  lcd.backlight();

  // Ultrasonic sensor pin modes
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  lcd.setCursor(0, 0);
  lcd.print("Enter weight (kg)");
}


void loop() {
  if (Serial.available() > 0) {
    float weight = Serial.parseFloat(); // Read weight from serial input
    float height = measureHeight();

    if (weight > 0 && height > 0) {
      BMI userBMI(weight, height);
      float bmi = userBMI.calculateBMI();
      userBMI.displayBMI(bmi);
    }
  }
}

// Function to measure height using ultrasonic sensor
float measureHeight() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  long duration = pulseIn(echoPin, HIGH);
  float distance = duration * 0.034 / 2; // Convert to cm

  // Convert to meters
  return distance / 100.0;
}