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

// -------------------- Sensor Pins --------------------
#define DHTPIN 15
#define DHTTYPE DHT22
#define GAS_PIN 34

#define BUZZER 18
#define FAN 19
#define LED_NORMAL 23
#define LED_ALERT 22

// -------------------- ThingSpeak Settings --------------------
const char* ssid = "Wokwi-GUEST";   // Wokwi default WiFi
const char* password = "";          // No password in Wokwi
String apiKey = "HVEN8GKOI950GIWW";
const char* server = "http://api.thingspeak.com/update";

DHT dht(DHTPIN, DHTTYPE);

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

  dht.begin();
  pinMode(GAS_PIN, INPUT);
  pinMode(BUZZER, OUTPUT);
  pinMode(FAN, OUTPUT);
  pinMode(LED_NORMAL, OUTPUT);
  pinMode(LED_ALERT, OUTPUT);

  // -------------------- WiFi Connection --------------------
  Serial.println("Connecting to WiFi...");
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(300);
    Serial.print(".");
  }

  Serial.println("\nWiFi Connected!");
}

void loop() {
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();
  int gasValue = analogRead(GAS_PIN);

  // -------------------- Serial Monitoring --------------------
  Serial.print("Temperature: "); Serial.print(temperature);
  Serial.print(" °C | Humidity: "); Serial.print(humidity);
  Serial.print("% | Gas Value: "); Serial.println(gasValue);

  // -------------------- Local Action Logic --------------------
  if (temperature > 35 || gasValue > 2000) {
    digitalWrite(BUZZER, HIGH);
    digitalWrite(FAN, HIGH);
    digitalWrite(LED_ALERT, HIGH);
    digitalWrite(LED_NORMAL, LOW);
  } else {
    digitalWrite(BUZZER, LOW);
    digitalWrite(FAN, LOW);
    digitalWrite(LED_ALERT, LOW);
    digitalWrite(LED_NORMAL, HIGH);
  }

  // -------------------- Upload to ThingSpeak --------------------
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;

    String url = String(server) + "?api_key=" + apiKey +
                 "&field1=" + String(temperature) +
                 "&field2=" + String(humidity) +
                 "&field3=" + String(gasValue);

    http.begin(url);
    int httpCode = http.GET();

    if (httpCode > 0) {
      Serial.print("ThingSpeak Response: ");
      Serial.println(httpCode);
    } else {
      Serial.print("Error sending data: ");
      Serial.println(http.errorToString(httpCode).c_str());
    }

    http.end();
  } else {
    Serial.println("WiFi Disconnected! Skipping upload...");
  }

  delay(20000);  // ThingSpeak: minimum 15 sec
}