#include <WiFi.h>
#include <PubSubClient.h>
#include <DHTesp.h>

const int DHT_PIN = 14;
DHTesp dht;
const char* ssid = "Wokwi-GUEST"; // wifi ssid
const char* password = "";
const char* mqtt_server = "broker.emqx.io";
const char* server = "api.thingspeak.com";
const char* channelID = "2359759";
const char* writeAPIKey = "DCSQSHJ7WBEWHP82";

WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;
float temp = 0;
float hum = 0;

void setup_wifi() {
  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  randomSeed(micros());

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    String clientId = "ESP32Client-";
    clientId += String(random(0xffff), HEX);
    if (client.connect(clientId.c_str())) {
      Serial.println("Connected");
      client.subscribe("/ThinkIOT/Subscribe");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

void setup() {
  pinMode(2, OUTPUT);
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
  dht.setup(DHT_PIN, DHTesp::DHT22);
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  unsigned long now = millis();
  if (now - lastMsg > 2000) {
    lastMsg = now;
    TempAndHumidity data = dht.getTempAndHumidity();

    String tempStr = String(data.temperature, 2);
    String humStr = String(data.humidity, 1);

    // Publish temperature and humidity to MQTT topics
    client.publish("/Thinkitive/temp", tempStr.c_str());
    client.publish("/Thinkitive/hum", humStr.c_str());

    // Publish to ThingSpeak via MQTT
    String topic = "channels/" + String(channelID) + "/publish/" + String(writeAPIKey);
    String payload = "field1=" + tempStr + "&field2=" + humStr;
    client.publish(topic.c_str(), payload.c_str());

    Serial.print("Temperature: ");
    Serial.println(tempStr);
    Serial.print("Humidity: ");
    Serial.println(humStr);
  }
}