// ---------------- BLYNK TEMPLATE ----------------
#define BLYNK_TEMPLATE_ID "TMPL3IPmjAidu"
#define BLYNK_TEMPLATE_NAME "Gas Leak Sensor"
#define BLYNK_AUTH_TOKEN "UCPDQmwaExijwhIDK_3TgiD8XUeoiBs8"

// ---------------- LIBRARIES ----------------
#include <WiFi.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <BlynkSimpleEsp32.h>

// ---------------- WIFI ----------------
char ssid[] = "SajMu";
char pass[] = "Ga@2006";

// ---------------- LCD ----------------
LiquidCrystal_I2C lcd(0x27, 16, 2);

// ---------------- PINS ----------------
#define GAS_SENSOR 34
#define GREEN_LED 18
#define RED_LED 19
#define BUZZER 23
#define BUTTON 4

// ---------------- VARIABLES ----------------
int threshold = 2000;   // Adjust after testing
bool alarmActive = false;

// ---------------- SETUP ----------------
void setup() {
  Serial.begin(115200);

  pinMode(GREEN_LED, OUTPUT);
  pinMode(RED_LED, OUTPUT);
  pinMode(BUZZER, OUTPUT);
  pinMode(BUTTON, INPUT_PULLUP);

  // LCD setup
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Gas System...");
  delay(2000);
  lcd.clear();

  // Connect WiFi + Blynk
  Blynk.begin(BLYNK_AUTH_TOKEN, ssid, pass);
}

// ---------------- LOOP ----------------
void loop() {
  Blynk.run();

  int gasValue = analogRead(GAS_SENSOR);

  Serial.print("Gas Value: ");
  Serial.println(gasValue);

  // Display gas value
  lcd.setCursor(0, 0);
  lcd.print("Gas: ");
  lcd.print(gasValue);
  lcd.print("   ");

  // GAS DETECTED
  if (gasValue > threshold && !alarmActive) {
    digitalWrite(RED_LED, HIGH);
    digitalWrite(GREEN_LED, LOW);
    digitalWrite(BUZZER, HIGH);
    alarmActive = true;

    lcd.setCursor(0, 1);
    lcd.print("DANGER!       ");

    Serial.println("GAS LEAK!");

    // Send notification
    Blynk.logEvent("gas_alert", "Gas Leak Detected!");
  }

  // SAFE
  else if (gasValue <= threshold) {
    digitalWrite(GREEN_LED, HIGH);
    digitalWrite(RED_LED, LOW);
    digitalWrite(BUZZER, LOW);
    alarmActive = false;

    lcd.setCursor(0, 1);
    lcd.print("SAFE          ");
  }

  // RESET BUTTON
  if (digitalRead(BUTTON) == LOW) {
    digitalWrite(BUZZER, LOW);
    alarmActive = false;

    lcd.setCursor(0, 1);
    lcd.print("RESET DONE    ");

    Serial.println("Reset Pressed");
    delay(500);
  }

  delay(500);
}