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

#define LDRPIN 34         // Pin sensor LDR
#define RELAYPIN 16       // Pin Relay

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "broker.hivemq.com";

WiFiClient espClient;
PubSubClient client(espClient);

void setup_wifi() {
  delay(10);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("WiFi connected");
}

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

  if (String(topic) == "esp32/1/dht11") {
    if (message.indexOf("Temperature") >= 0) {
      int tempIndex = message.indexOf("Temperature") + 13;
      int tempEndIndex = message.indexOf("°C");
      String tempString = message.substring(tempIndex, tempEndIndex);
      int temp = tempString.toInt();
      
      if (temp > 30) {
        digitalWrite(RELAYPIN, HIGH);
        client.publish("esp32/2/relay", "ON");  // Notify relay is ON
        Serial.println("Relay ON (Temperature > 30°C)");
      } else {
        digitalWrite(RELAYPIN, LOW);
        client.publish("esp32/2/relay", "OFF"); // Notify relay is OFF
        Serial.println("Relay OFF (Temperature <= 30°C)");
      }
    }
  }
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    if (client.connect("ESP32_B")) {
      Serial.println("connected");
      client.subscribe("esp32/1/dht11");  // Subscribing to sensor data topic
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  pinMode(RELAYPIN, OUTPUT);
  digitalWrite(RELAYPIN, LOW);
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}

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