#include <WiFi.h> // For ESP32 (use <ESP8266WiFi.h> if using ESP8266)
#include <ThingSpeak.h> // ThingSpeak library

// --- Pin Configuration ---
const int gasSensorPin = 34; // Analog pin connected to MQ sensor

// --- WiFi Configuration ---
const char* WIFI_NAME = "Wokwi-GUEST"; // Your Wi-Fi SSID
const char* WIFI_PASSWORD = ""; // Your Wi-Fi password

// --- ThingSpeak Configuration ---
unsigned long myChannelNumber =  3102966; // Replace with your ThingSpeak Channel ID
const char* myWriteAPIKey = "O51XD4FIEEZNA67O"; // Replace with your Write API Key

WiFiClient client;

int sensorValue;

void setup() {
  Serial.begin(9600);
  delay(100);
  Serial.println("Gas Sensor with ThingSpeak");
  
  // --- Connect to Wi-Fi ---
  WiFi.begin(WIFI_NAME, WIFI_PASSWORD);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi Connected!");
  
  // --- Initialize ThingSpeak ---
  ThingSpeak.begin(client);

  delay(2000); // Warm-up time for MQ sensor
}

void loop() {
  // --- Read gas sensor value ---
  sensorValue = analogRead(gasSensorPin);
  Serial.print("Sensor Value: ");
  Serial.print(sensorValue);

  String gasType;

  // --- Identify gas type based on threshold ---
  if (sensorValue < 200) {
    gasType = "Clean Air";
  } 
  else if (sensorValue >= 200 && sensorValue < 400) {
    gasType = "LPG/Propane";
  } 
  else if (sensorValue >= 400 && sensorValue < 600) {
    gasType = "Carbon Monoxide";
  } 
  else if (sensorValue >= 600) {
    gasType = "Smoke/Alcohol";
  }

  Serial.print(" - ");
  Serial.println(gasType);

  // --- Send data to ThingSpeak ---
  ThingSpeak.setField(1, sensorValue); // Field 1 → raw sensor value
  //ThingSpeak.setField(2, gasType); // Field 2 → detected gas type (as text)

  int status = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);
  
  if (status == 200) {
    Serial.println("Data sent successfully to ThingSpeak!");
  } else {
    Serial.println("Error sending data to ThingSpeak. HTTP error code: " + String(status));
  }

  delay(20000); // ThingSpeak accepts updates every 15 seconds (20s safe)
}