#define BLYNK_TEMPLATE_ID "TMPL3d_EQhRys"
#define BLYNK_TEMPLATE_NAME "SMART HOME AUTOMATION AND GAS LEAK DETECTION"
#define BLYNK_AUTH_TOKEN "UDSwyJp1cEOz7Ijh92nR3p7i-av372Kx"


#include <MQUnifiedsensor.h>
#include <WiFi.h>
#include <BlynkSimpleEsp32.h>
#include <LiquidCrystal_I2C.h>


#define BLYNK_PRINT Serial

char auth[] = BLYNK_AUTH_TOKEN;
char ssid[] = "Wokwi-GUEST";
char pass[] = "";

#define         Board                   ("Arduino UNO")
#define         MQ2_Pin                 (A0)  
#define         Type                    ("MQ-2") 
#define         Voltage_Resolution      (5)
#define         ADC_Bit_Resolution      (10) 
#define         RatioMQ2CleanAir        (9.83) 

MQUnifiedsensor MQ2(Board, Voltage_Resolution, ADC_Bit_Resolution, MQ2_Pin, Type);

LiquidCrystal_I2C lcd(0x27, 20, 4);

#define button1_pin 13
#define button2_pin 12
#define button3_pin 14
#define button4_pin 27

#define relay1_pin 5
#define relay2_pin 18
#define relay3_pin 19
#define relay4_pin 23

int relay1_state = 0;
int relay2_state = 0;
int relay3_state = 0;
int relay4_state = 0;

#define button1_vpin    V1
#define button2_vpin    V2
#define button3_vpin    V3 
#define button4_vpin    V4

const int buzzer_pin = 25;

BlynkTimer timer;

BLYNK_CONNECTED() {
  Blynk.syncVirtual(button1_vpin);
  Blynk.syncVirtual(button2_vpin);
  Blynk.syncVirtual(button3_vpin);
  Blynk.syncVirtual(button4_vpin);
}

BLYNK_WRITE(button1_vpin) {
  relay1_state = param.asInt();
  digitalWrite(relay1_pin, relay1_state);
}

BLYNK_WRITE(button2_vpin) {
  relay2_state = param.asInt();
  digitalWrite(relay2_pin, relay2_state);
}

BLYNK_WRITE(button3_vpin) {
  relay3_state = param.asInt();
  digitalWrite(relay3_pin, relay3_state);
}

BLYNK_WRITE(button4_vpin) {
  relay4_state = param.asInt();
  digitalWrite(relay4_pin, relay4_state);
}

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

  MQ2.setRegressionMethod(1); 
  MQ2.setA(574.25); MQ2.setB(-2.222); 
  pinMode(MQ2_Pin, INPUT);
  pinMode(buzzer_pin, OUTPUT);
  
  MQ2.init(); 

  lcd.init();
  lcd.backlight();
  
  Serial.print("Calibrating please wait.");
  float calcR0 = 0;
  for(int i = 1; i<=10; i ++) {
    MQ2.update(); 
    calcR0 += MQ2.calibrate(RatioMQ2CleanAir);
    Serial.print(".");
  }
  MQ2.setR0(calcR0/10);
  Serial.println("  done!.");
  
  if(isinf(calcR0)) {
    Serial.println("Warning: Connection issue, R0 is infinite (Open circuit detected). Please check your wiring and supply");
    while(1);
  }
  if(calcR0 == 0) {
    Serial.println("Warning: Connection issue found, R0 is zero (Analog pin shorts to ground). Please check your wiring and supply");
    while(1);
  }

  MQ2.serialDebug(true);

  pinMode(button1_pin, INPUT_PULLUP);
  pinMode(button2_pin, INPUT_PULLUP);
  pinMode(button3_pin, INPUT_PULLUP);
  pinMode(button4_pin, INPUT_PULLUP);

  pinMode(relay1_pin, OUTPUT);
  pinMode(relay2_pin, OUTPUT);
  pinMode(relay3_pin, OUTPUT);
  pinMode(relay4_pin, OUTPUT);

  digitalWrite(relay1_pin, HIGH);
  digitalWrite(relay2_pin, HIGH);
  digitalWrite(relay3_pin, HIGH);
  digitalWrite(relay4_pin, HIGH);

  Blynk.begin(auth, ssid, pass);
}

void loop() {
  MQ2.update(); 
  MQ2.readSensor(); 

  Serial.print("Gas : ");
  Serial.println(MQ2.readSensor());

  Blynk.virtualWrite(V5, MQ2.readSensor()); // Virtual Pin V5 for gas sensor data

  lcd.setCursor(0, 0);
  lcd.print("Gas : ");
  lcd.println(MQ2.readSensor());

  if(MQ2.readSensor() > 700) {
    tone(buzzer_pin, 1000); 
    delay(2000);        
    noTone(buzzer_pin);     
    delay(100); 
    lcd.setCursor(0, 1);
    lcd.println("GAS LEAKAGE");
    lcd.setCursor(0, 2);
    lcd.println("DETECTED");
  } else {
    noTone(buzzer_pin);
    lcd.setCursor(0, 1);
    lcd.println("NO LEAKAGE");
    lcd.setCursor(0, 2);
    lcd.println("        ");
  }

  Blynk.run();
  timer.run();
  listen_push_buttons();
}

void listen_push_buttons() {
  if(digitalRead(button1_pin) == LOW) {
    delay(100);
    control_relay(1);
    Blynk.virtualWrite(button1_vpin, relay1_state); 
  } else if (digitalRead(button2_pin) == LOW) {
    delay(100);
    control_relay(2);
    Blynk.virtualWrite(button2_vpin, relay2_state); 
  } else if (digitalRead(button3_pin) == LOW) {
    delay(100);
    control_relay(3);
    Blynk.virtualWrite(button3_vpin, relay3_state); 
  } else if (digitalRead(button4_pin) == LOW) {
    delay(100);
    control_relay(4);
    Blynk.virtualWrite(button4_vpin, relay4_state); 
  }
}

void control_relay(int relay) {
  if(relay == 1) {
    relay1_state = !relay1_state;
    digitalWrite(relay1_pin, relay1_state);
    Serial.print("Relay1 State = ");
    Serial.println(relay1_state);
    delay(50);
  } else if(relay == 2) {
    relay2_state = !relay2_state;
    digitalWrite(relay2_pin, relay2_state);
    delay(50);
  } else if(relay == 3) {
    relay3_state = !relay3_state;
    digitalWrite(relay3_pin, relay3_state);
    delay(50);
  } else if(relay == 4) {
    relay4_state = !relay4_state;
    digitalWrite(relay4_pin, relay4_state);
    delay(50);
  }
}