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

LiquidCrystal_I2C lcd(0x27, 16, 2); // set the LCD address to 0x27 for a 16 chars and 2 line display
int calibratingGlucoseLevel = 700000;
#define mq7_a0    A0
#define mq135_a1  A1
#define mq2_a2    A2
#define mq5_a3    A3

int coLevel = 0;
int mq135_Level = 0;
int mq2_Level = 0;
int mq5_Level = 0;

const int pushButtonPin = 8;

//----------------------------------------------------------------------------------------------------
//    MQ7
// Calibration resistance value (Ro)
const float Ro = 10.0;

// Coefficients for the non-linear relation
const float coefficientA = 84.771349776;
const float coefficientB = -0.6505447222;

const char* co_results[] = {"No Diabetes", "Diabetes Type 1", "Diabetes Type 2"};

float baselineRsRo = 1.0; // Initialize baseline Rs/Ro to a known value

// Calculate Rs/ro ratio and PPM using baselineRsRo
float voltage;
float Rs_ro_ratio;
float PPM;

void calculatePPM_MQ7() {
  // Calculate Rs/ro ratio and PPM using baselineRsRo
  voltage = (coLevel / 1023.0) * 5.0;
  Rs_ro_ratio = (5.0 - voltage) / voltage * (Ro / baselineRsRo);
  PPM = coefficientA * pow(Rs_ro_ratio, coefficientB);
}
//----------------------------------------------------------------------------------------------------
//----------------------------------------------------------------------------------------------------
//    MQ135
// Calibration resistance value (Ro) for MQ-135 sensor
const float mq135Ro = 10.0;

// Coefficients for the non-linear relation for MQ-135 sensor (acetone)
const float mq135CoefficientA = 57.8082622183;
const float mq135CoefficientB = -0.2569841436;

const char* acetone_results[] = {"Healthy", "T2DM"};

float mq135BaselineRsRo = 1.0; // Initialize baseline Rs/Ro for MQ-135 sensor
float mq135PPM;
int healthResult;

float MQ135calculatePPM(int rawValue, float Ro, float coefficientA, float coefficientB) {
  float voltage = (rawValue / 1023.0) * 5.0;
  float Rs_ro_ratio = (5.0 - voltage) / voltage * (Ro / mq135BaselineRsRo);
  return coefficientA * pow(Rs_ro_ratio, coefficientB);
}

int determineHealth(float mq135PPM) {
  if (mq135PPM >= 10.73 && mq135PPM <= 57.13) {
    return 0; // Healthy
  } else if (mq135PPM >= 78.0 && mq135PPM <= 444.0) {
    return 1; // T2DM
  }
  return -1; // Invalid result
}
//----------------------------------------------------------------------------------------------------
//----------------------------------------------------------------------------------------------------
//    MQ2
// Calibration resistance value (Ro) for MQ-2 sensor
const float mq2Ro = 10.0;

// Coefficients for the non-linear relation for MQ-2 sensor (ethylene)
const float mq2CoefficientA = 2233.153446891;
const float mq2CoefficientB = -2.757374515;

const char* diabetes_results[] = {"Healthy", "Diabetes Type 2"};

float mq2BaselineRsRo = 1.0; // Initialize baseline Rs/Ro for MQ-2 sensor

float mq2PPM;
int diabetesResult;

float MQ2calculatePPM(int rawValue, float Ro, float coefficientA, float coefficientB) {
  float voltage = (rawValue / 1023.0) * 5.0;
  float Rs_ro_ratio = (5.0 - voltage) / voltage * (Ro / mq2BaselineRsRo);
  return coefficientA * pow(Rs_ro_ratio, coefficientB);
}

int detectDiabetes(float mq2PPM) {
  if (mq2PPM < 10.73) {
    return 0; // Healthy
  } else if (mq2PPM >= 10.73 && mq2PPM <= 57.13) {
    return 0; // Healthy
  } else if (mq2PPM >= 78 && mq2PPM <= 444) {
    return 1; // Diabetes Type 2
  } else {
    return 1; // Diabetes Type 2
  }
}
//----------------------------------------------------------------------------------------------------
//----------------------------------------------------------------------------------------------------
//    MQ5
// Calibration resistance value (Ro) for MQ-5 sensor
const float mq5Ro = 10.0;

// Coefficients for the non-linear relation for MQ-5 sensor
const float mq5CoefficientA = 4122.204007;
const float mq5CoefficientB = -3.539510656;

// Correlation equation parameters
const float correlationCoefficient = 0.9098882772;
const float correlationIntercept = 12.6462318032;

const char* MQ5diabetes_results[] = {"Healthy", "Diabetes Type 1"};

float mq5BaselineRsRo = 1.0; // Initialize baseline Rs/Ro for MQ-5 sensor
float mq5PPM;
float plasmaGlucose;
int MQ5diabetesResult;

float MQ5calculatePPM(int rawValue, float Ro, float coefficientA, float coefficientB) {
  float voltage = (rawValue / 1023.0) * 5.0;
  Serial.println(voltage);
  float Rs_ro_ratio = (5.0 - voltage) / voltage * (Ro / mq5BaselineRsRo);
  Serial.println(Rs_ro_ratio);
  return coefficientA * pow(Rs_ro_ratio, coefficientB);
}

float calculatePlasmaGlucose(float mq5PPM) {
  // Calculate plasma glucose using the correlation equation
  float predictedGlucose = correlationCoefficient * mq5PPM + correlationIntercept;
  return predictedGlucose;
}

int MQ5detectDiabetes(float plasmaGlucose) {
  // Diabetes detection logic using plasma glucose value
  // If Plasma Glucose is less than 140: Healthy
  // If Plasma Glucose is greater than or equal to 140: Diabetes Type 1
  if (plasmaGlucose < 140.0) {
    return 0; // Healthy
  } else {
    return 1; // Diabetes Type 1
  }
}
//----------------------------------------------------------------------------------------------------
void setup() {
  Serial.begin(9600);
  pinMode(mq7_a0, INPUT);
  pinMode(pushButtonPin, INPUT_PULLUP); // Set the push button pin as input with pull-up
  lcd.init();
  lcd.init();
  lcd.backlight();
  //lcd.print("Welcome!");
  //lcd.setCursor(0, 1);
  //lcd.print("Press the button");
}

void loop() {
  coLevel     = analogRead(mq7_a0);
  mq135_Level = analogRead(mq135_a1);
  mq2_Level   = analogRead(mq2_a2);
  mq5_Level   = analogRead(mq5_a3);
  Serial.print(coLevel);
  Serial.print("\t");
  Serial.print(mq135_Level);
  Serial.print("\t");
  Serial.print(mq2_Level);
  Serial.print("\t");
  Serial.print(mq5_Level);
  Serial.print("\n");
  calculatePPM_MQ7();
  // Calculate acetone PPM using MQ-135 sensor's equation
  mq135PPM = MQ135calculatePPM(mq135_Level, mq135Ro, mq135CoefficientA, mq135CoefficientB);
  // Calculate ethylene PPM using MQ-2 sensor's equation
  mq2PPM   = MQ2calculatePPM(mq2_Level, mq2Ro, mq2CoefficientA, mq2CoefficientB);
  // Calculate PPM using MQ-5 sensor's equation
  mq5PPM   = MQ5calculatePPM(mq5_Level, mq5Ro, mq5CoefficientA, mq5CoefficientB);
  mq5PPM = mq5PPM * calibratingGlucoseLevel;
  // Calculate plasma glucose using the correlation equation
  plasmaGlucose = calculatePlasmaGlucose(mq5PPM);
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("S1:");
  lcd.print(PPM, 1);//MQ7
  lcd.setCursor(8, 0);
  lcd.print("S2:");
  lcd.print(mq135PPM, 2);//MQ135
  lcd.setCursor(0, 1);
  lcd.print("S3:");
  lcd.print(mq2PPM, 1);//MQ2
  lcd.setCursor(8, 1);
  lcd.print("S4:");
  lcd.print(plasmaGlucose, 1); //mq5PPM plasmaGlucose, 1);//MQ5
  delay(100);
  int buttonState = digitalRead(pushButtonPin);
  if (buttonState == LOW) {
    buttonPressReading();
  }
}//end of LOOP


void buttonPressReading() {
  lcd.clear();
  lcd.setCursor(0, 1);
  calculatePPM_MQ7();
  mq135PPM = MQ135calculatePPM(mq135_Level, mq135Ro, mq135CoefficientA, mq135CoefficientB);
  // Determine health condition based on acetone PPM
  healthResult = determineHealth(mq135PPM);
  // Calculate ethylene PPM using MQ-2 sensor's equation
  mq2PPM = MQ2calculatePPM(mq2_Level, mq2Ro, mq2CoefficientA, mq2CoefficientB);
  diabetesResult = detectDiabetes(mq2PPM);
  // Calculate PPM using MQ-5 sensor's equation
  mq5PPM = MQ5calculatePPM(mq5_Level, mq5Ro, mq5CoefficientA, mq5CoefficientB);
  mq5PPM = mq5PPM * calibratingGlucoseLevel;
  // Calculate plasma glucose using the correlation equation
  plasmaGlucose = calculatePlasmaGlucose(mq5PPM);
  // Detect diabetes type 1 or healthy
  MQ5diabetesResult = MQ5detectDiabetes(plasmaGlucose);

  displayResult(PPM);


  delay(1000);

  lcd.clear();
  lcd.print("Welcome!");
  lcd.setCursor(0, 1);
  lcd.print("Press the button");
  while (digitalRead(pushButtonPin) == LOW) {
  }
}

void displayResult(float ppm) {
  int result = -1;

  if (ppm >= 3.3 && ppm < 4.7) {
    result = 1;
  } else if (ppm <= 5.4 && ppm >= 4.8) {
    result = 2;
  } else {
    result = 0;
  }

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("S1:");
  lcd.print(PPM, 1);//MQ7
  lcd.print(" ppm");
  lcd.setCursor(0, 1);
  lcd.print(co_results[result]);
  delay(5000);
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("S2:");
  lcd.print(mq135PPM, 2);//MQ135
  lcd.print(" ppm");
  lcd.setCursor(0, 1);
  lcd.print(acetone_results[healthResult]);
  delay(5000);
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("S3:");
  lcd.print(mq2PPM, 1);//MQ2
  lcd.print(" ppm");
  lcd.setCursor(0, 1);
  lcd.print(diabetes_results[diabetesResult]);
  delay(5000);
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("S4:");
  lcd.print(plasmaGlucose, 1);//MQ5
  lcd.print(" mg/dL");
  lcd.setCursor(0, 1);
  lcd.print(MQ5diabetes_results[MQ5diabetesResult]);
  delay(5000);
  if (co_results[result] == "No Diabetes" && acetone_results[healthResult] == "Healthy" && diabetes_results[diabetesResult] == "Healthy" && MQ5diabetes_results[MQ5diabetesResult] == "Healthy") {
    //Write OK
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("You are Healthy");
    delay(10000);
  }
  else {
    //Write See Doctor
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Please See your");
    lcd.setCursor(0, 1);
    lcd.print("   Doctor");
    delay(10000);
  }
}