#define BLYNK_TEMPLATE_ID "TMPL3YrO8hPSx"
#define BLYNK_TEMPLATE_NAME "Gas Detector"
#define BLYNK_AUTH_TOKEN "D3JMx-k-lBgpD2kdENfNnAzdJ_qQKl2_"

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

#define GAS_SENSOR 34   // potentiometer connected to GPIO34

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

bool warningActive = false;   // tracks if warning notification already sent

void setup()
{
  Serial.begin(115200);

  pinMode(GAS_SENSOR, INPUT);

  Serial.println("Connecting to Blynk...");
  Blynk.begin(BLYNK_AUTH_TOKEN, ssid, pass);
}

void loop()
{
  Blynk.run();

  int sensorValue = analogRead(GAS_SENSOR);

  // ESP32 ADC range (0–4095) → convert to 0–1023
  int gasValue = map(sensorValue, 0, 4095, 0, 1023);

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

  // send value to Blynk gauge
  Blynk.virtualWrite(V0, gasValue);

  // SAFE ZONE
  if (gasValue < 170)
  {
    Blynk.virtualWrite(V1, "SAFE");
    Blynk.virtualWrite(V2, 0);

    warningActive = false;   // reset alert
  }

  // WARNING ZONE
  else if (gasValue >= 170 && gasValue <= 550)
  {
    Blynk.virtualWrite(V1, "WARNING");
    Blynk.virtualWrite(V2, 1);

    // send notification only once when entering warning zone
    if (!warningActive)
    {
      Blynk.logEvent("gas_leakage_alert");
      warningActive = true;
    }
  }

  // DANGER ZONE
  else if (gasValue > 550)
  {
    Blynk.virtualWrite(V1, "DANGER");
    Blynk.virtualWrite(V2, 1);
  }

  delay(2000);
}