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

// --- Sensor and Actuator Pins ---
#define DHTPIN 15
#define DHTTYPE DHT22
#define PIR_PIN 27
#define LDR_PIN 34
#define LED1_PIN 16
#define LED2_PIN 17
#define BUZZER_PIN 26

// --- DHT Sensor ---
DHT dht(DHTPIN, DHTTYPE);

// --- MQTT Credentials ---
const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqttServer = "broker.hivemq.com";
const char* topicTemperature = "home/sensors/temperature";
const char* topicHumidity = "home/sensors/humidity";
const char* topicLight = "home/sensors/light";
const char* topicMotion = "home/sensors/motion";
const char* topicAlarm = "home/actuators/alarm";
const char* topicBuzzerState = "home/actuators/buzzer"; // New topic for buzzer state

WiFiClient espClient;
PubSubClient client(espClient);

// --- Thresholds ---
#define LUMINOSITY_THRESHOLD 2000

void setup_wifi() {
  delay(10);
  Serial.println("Connecting to WiFi...");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi connected");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    if (client.connect("ESP32Client")) {
      Serial.println("connected");
      client.subscribe(topicAlarm);
      Serial.println("Subscribed to alarm topic");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

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 arrived [");
  Serial.print(topic);
  Serial.print("]: ");
  Serial.println(message);

  if (String(topic) == topicAlarm) {
    if (message == "ON") {
      Serial.println("Alarm triggered via MQTT");
      triggerAlarm();
    } else if (message == "OFF") {
      Serial.println("Alarm deactivated via MQTT");
      digitalWrite(BUZZER_PIN, LOW);
      client.publish(topicBuzzerState, "OFF"); // Publish buzzer state as OFF
    }
  }
}

void setup() {
  Serial.begin(115200);
  Serial.println("Initializing system...");

  // Initialize Sensors
  dht.begin();
  pinMode(PIR_PIN, INPUT);
  pinMode(LED1_PIN, OUTPUT);
  pinMode(LED2_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);

  // Initialize WiFi and MQTT
  setup_wifi();
  client.setServer(mqttServer, 1883);
  client.setCallback(callback);

  Serial.println("System initialized");
}

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

  // --- Read DHT Sensor ---
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();
  if (!isnan(temperature) && !isnan(humidity)) {
    Serial.print("Temperature: ");
    Serial.println(temperature);
    Serial.print("Humidity: ");
    Serial.println(humidity);
    client.publish(topicTemperature, String(temperature).c_str());
    client.publish(topicHumidity, String(humidity).c_str());
  } else {
    Serial.println("Failed to read from DHT sensor");
  }

  // --- Read PIR Sensor ---
  int motionDetected = digitalRead(PIR_PIN);
  if (motionDetected == HIGH) {
    Serial.println("Motion detected!");
    client.publish(topicMotion, "Motion detected");
  } else {
    Serial.println("No motion");
    client.publish(topicMotion, "No motion");
  }

  // --- Read LDR Sensor ---
  int lightLevel = analogRead(LDR_PIN);
  Serial.print("Light level: ");
  Serial.println(lightLevel);
  client.publish(topicLight, String(lightLevel).c_str());

  // --- LED Control ---
  if (lightLevel < LUMINOSITY_THRESHOLD && motionDetected == HIGH) {
    Serial.println("Turning LEDs ON");
    digitalWrite(LED1_PIN, HIGH);
    digitalWrite(LED2_PIN, HIGH);
  } else {
    Serial.println("Turning LEDs OFF");
    digitalWrite(LED1_PIN, LOW);
    digitalWrite(LED2_PIN, LOW);
  }

  delay(2000);
}

void triggerAlarm() {
  Serial.println("Alarm triggered! Activating buzzer...");
  digitalWrite(BUZZER_PIN, HIGH);
  client.publish(topicBuzzerState, "ON"); // Publish buzzer state as ON
  delay(500);
  digitalWrite(BUZZER_PIN, LOW);
  client.publish(topicBuzzerState, "OFF"); // Publish buzzer state as OFF
  Serial.println("Buzzer deactivated");
}