#include <WiFi.h>
#include <DHT.h>
#include <ThingSpeak.h>

#define DHTPIN 4         // DHT22 connected to GPIO4
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

const char* ssid = "Wokwi-GUEST";
const char* password = "";

WiFiClient client;
unsigned long myChannelNumber = 3099053;      
const char * myWriteAPIKey = "XOGEJAJP5AOKQT8W";    

void setup() {
  Serial.begin(100);
  dht.begin();

  Serial.print("Connecting to WiFi");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi connected!");

  ThingSpeak.begin(client);
}

void loop() {
  float h = dht.readHumidity();
  float t = dht.readTemperature();
  int gasValue = analogRead(34); // MQ135 connected to GPIO34

  if (isnan(h) || isnan(t)) {
    Serial.println("Failed to read from DHT22 sensor!");
    delay(2000);
    return;
  }

  Serial.print("Temp: "); Serial.println(t);
  Serial.print("Humidity: "); Serial.println(h);
  Serial.print("Gas Value: "); Serial.println(gasValue);

  ThingSpeak.setField(1, t);
  ThingSpeak.setField(2, h);
  ThingSpeak.setField(3, gasValue);

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

  delay(15000); // Must wait 15 sec for ThingSpeak
}