#include <Wire.h>
#include <WiFi.h>
#include <LiquidCrystal_I2C.h>
#include <MQUnifiedsensor.h>
#include "DHTesp.h"
#include <PubSubClient.h>
#include "ThingSpeak.h"  // Include ThingSpeak library

#define Board ("ESP-32")
#define Pin (4)
#define Type ("MQ-2")
#define Voltage_Resolution (3.3)
#define ADC_Bit_Resolution (12)
#define RatioMQ2CleanAir (9.83)

MQUnifiedsensor MQ2(Board, Voltage_Resolution, ADC_Bit_Resolution, Pin, Type);
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Define pins for LEDs and Buzzer
#define GREEN_LED_PIN (14)
#define YELLOW_LED_PIN (12)
#define RED_LED_PIN (13)
#define BUZZER_PIN (2)
const int DHT_PIN = 15;
DHTesp dhtSensor;


void setup() {
  Serial.begin(9600); 

  lcd.init();
  lcd.begin(16, 2);
  lcd.clear();
  lcd.backlight();
  lcd.print("START"); 
  delay(1000);

  // Set LED and buzzer pins as outputs
  pinMode(GREEN_LED_PIN, OUTPUT);
  pinMode(YELLOW_LED_PIN, OUTPUT);
  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(Pin , INPUT);
  dhtSensor.setup(DHT_PIN, DHTesp::DHT22);

  MQ2.setRegressionMethod(1); 
  MQ2.setA(36974);
  MQ2.setB(-3.10);
  MQ2.init();
  /*
    Exponential regression:
    Gas    | a      | b
    H2     | 987.99 | -2.162
    LPG    | 574.25 | -2.222
    
    CO     | 36974  | -3.109

    Alcohol| 3616.1 | -2.675
    Propane| 658.71 | -2.168
  */

  float calcR0 = 0;
  for (int i = 1; i <= 10; i++) {  // Reduced from 10 to 5 iterations
    MQ2.update();
    calcR0 += MQ2.calibrate(RatioMQ2CleanAir);
    delay(100);  // Added small delay to ensure stability
  }
  
  calcR0 /= 10;  // Calculate average
  MQ2.setR0(calcR0);
  Serial.print("R0: ");
  Serial.println(calcR0);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("MQ2 = ");
  lcd.print(calcR0);
  delay(500);
  
  if (isinf(calcR0) || calcR0 == 0) {
    Serial.println("Sensor Calibration Failed");
    while(1);
  }

  MQ2.serialDebug(true);
}

void loop() {
  TempAndHumidity data = dhtSensor.getTempAndHumidity();
  float temperature = data.temperature;
  float humidity = data.humidity;

  lcd.clear();
  lcd.setCursor(0, 0); 
  lcd.print("Temp: ");
  lcd.print(temperature);
  lcd.print(" C");

  lcd.setCursor(0, 1); 
  lcd.print("Humid: ");
  lcd.print(humidity);
  lcd.print(" %");
  delay(2000);

  MQ2.update();
  MQ2.readSensor();
  int valor_gas = analogRead(Pin);
  valor_gas = map(valor_gas, 0, 4095, 0, 100);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("MQ2 = ");
  lcd.print(valor_gas);
  delay(2000);
  
  // Control LEDs based on gas levels
  if (valor_gas <= 70) {
    digitalWrite(GREEN_LED_PIN, HIGH);
    digitalWrite(YELLOW_LED_PIN, LOW);
    digitalWrite(RED_LED_PIN, LOW);
    noTone(BUZZER_PIN);
  } else if (valor_gas > 70 && valor_gas <= 85) {
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(YELLOW_LED_PIN, HIGH);
    digitalWrite(RED_LED_PIN, LOW);
    tone(BUZZER_PIN, 500);
    delay(2000);
    noTone(BUZZER_PIN);
  } else {
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(YELLOW_LED_PIN, LOW);
    digitalWrite(RED_LED_PIN, HIGH);
    tone(BUZZER_PIN, 1000);
  }
  delay(1000);
}