#include <WiFi.h>
#include <HTTPClient.h>

const char* ssid = "Wokwi-GUEST";        // Replace with your WiFi SSID
const char* password = ""; // Replace with your WiFi Password

String apiKey = "7XJ8I9DKZL4HT2G7";    // ThingSpeak API Key
const String server = "http://api.thingspeak.com/update";
int channelID = 2667740;

const int gasSensorPin = 34;  // Gas sensor pin
const int ledPin = 22;        // LED pin
int threshold = 400;          // Gas level threshold for LED activation

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

  // Set LED pin as output
  pinMode(ledPin, OUTPUT);

  // Connect to WiFi
  WiFi.begin(ssid, password);
  Serial.println("Connecting to WiFi...");
  
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print(".");
  }
  
  Serial.println("");
  Serial.println("Connected to WiFi");
}

void loop() {
  int gasLevel = analogRead(gasSensorPin);  // Read gas sensor value
  Serial.print("Gas Level: ");
  Serial.println(gasLevel);
  
  // Activate LED if gas level exceeds the threshold
  if (gasLevel > threshold) {
    digitalWrite(ledPin, HIGH);
  } else {
    digitalWrite(ledPin, LOW);
  }

  // Send data to ThingSpeak
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;

    // Convert server to String and concatenate the URL components
    String url = server + "?api_key=" + apiKey + "&field1=" + String(gasLevel);
    http.begin(url);

    int httpCode = http.GET();  // Send the request

    if (httpCode > 0) {
      String payload = http.getString();  // Get the response
      Serial.println("Data sent to ThingSpeak: " + payload);
    } else {
      Serial.println("Error in sending data");
    }

    http.end();  // End connection
  }

  delay(15000);  // Wait 15 seconds before sending data again (ThingSpeak limit)
}