#include <WiFi.h>
#include <PubSubClient.h>
#include <LiquidCrystal_I2C.h>
#include <DHTesp.h>

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "test.mosquitto.org";
const char* mqtt_topic = "Ridwan";

#define MSG_BUFFER_SIZE (50)

WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;
char msg[MSG_BUFFER_SIZE];
int value = 0;

LiquidCrystal_I2C lcd(0x27, 16, 2); // Initialize LCD

const int DHT_PIN = 15;
DHTesp dht;
const int ldrPin = 34;  // LDR connected to analog pin 34 on ESP32
const int relayPin = 13;  // Relay control pin
const float GAMMA = 0.7;
const float RL10 = 50;
const int luxThreshold = 500;  // Lux threshold for turning on the relay
volatile byte relayState = LOW;

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(".");
  }
  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]);
  }
  Serial.println();
}

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.publish(mqtt_topic, "D3 - TT"); // Publish on connect
      client.subscribe(mqtt_topic);
    } else {
      Serial.print("failed, rc = ");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  dht.setup(DHT_PIN, DHTesp::DHT22);  // Initialize DHT sensor
  client.setCallback(callback);
  lcd.init();
  lcd.backlight();
  pinMode(relayPin, OUTPUT);
  relayState = LOW;
  digitalWrite(relayPin, LOW);
}

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

  unsigned long now = millis();
  if (now - lastMsg > 2000) {
    lastMsg = now;
    int analogValue = analogRead(ldrPin);
    float voltage = analogValue * (3.3 / 4095.0);
    float resistance = (10000.0 * voltage) / (3.3 - voltage);
    float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1.0 / GAMMA));

    float temperature = dht.getTemperature();
    float humidity = dht.getHumidity();

    if (!isnan(lux) && !isinf(lux) && !isnan(temperature) && !isnan(humidity)) {
      snprintf(msg, MSG_BUFFER_SIZE, "Lux: %.2f, Temp: %.2f C, Humidity: %.2f %%", lux, temperature, humidity);
      Serial.print("Publish message: ");
      Serial.println(msg);
      client.publish(mqtt_topic, msg);

      lcd.setCursor(0, 0);
      lcd.print("Lux: ");
      lcd.print(lux);

      lcd.setCursor(0, 1);
      lcd.print("Temp: ");
      lcd.print(temperature);
      lcd.print("C  Humidity: ");
      lcd.print(humidity);
      lcd.print("%");

      if (lux > luxThreshold) {
        digitalWrite(relayPin, LOW);
        relayState = LOW;
      } else {
        digitalWrite(relayPin, HIGH);
        relayState = HIGH;
      }

      delay(2000);
      lcd.clear();
    } else {
      lcd.setCursor(0, 0);
      lcd.clear();
      lcd.println("Invalid Readings");
    }

    delay(1000);
  }
}