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

#define LDR 34
const float GAMMA = 0.7;
const float RL10 = 50;

const char *ssid = "Wokwi-GUEST";
const char *password = "";

#define TOKEN "kqjup0kvfjnfnz2gqdjp" // Access Token
const char *mqtt_server = "thingsboard.cloud";

WiFiClient wifiClient;
PubSubClient client(wifiClient);

int status = WL_IDLE_STATUS;

void setup() {
  Serial.begin(9600);
  delay(10);

  pinMode(LDR, INPUT);
  
  Serial.print("Connect to: ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);
  
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print("....");
  }
  
  Serial.print("\nIP Address: ");
  Serial.println(WiFi.localIP());
  
  Serial.print("Connected to: ");
  Serial.println(ssid);
  
  client.setServer(mqtt_server, 1883);
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  
  getData();
  delay(5000);
}

void getData() {
  int analogValue = analogRead(LDR);
  float voltage = (analogValue / 4095.0) * 3.3;
  float resistance = 2000 * voltage / (3.3 - voltage);
  float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));

  Serial.print("Lux: ");
  Serial.println(lux);

  String payload = "{";
  payload += "\"IntensitasCahaya\":";
  payload += lux;
  payload += "}";

  char attributes[100];
  payload.toCharArray(attributes, 100);

  client.publish("v1/devices/me/telemetry", attributes);
  client.publish("v1/devices/me/attributes", attributes);

  Serial.println(attributes);
}

void reconnect() {
  while (!client.connected()) {
    status = WiFi.status();
    
    if (status != WL_CONNECTED) {
      while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
      }
      Serial.println("\nConnected to WiFi");
    }

    Serial.print("Connecting to MQTT...");
    if (client.connect("ESP32Client", TOKEN, NULL)) {
      Serial.println(" [DONE]");
    } else {
      Serial.print("[FAILED] [rc = ");
      Serial.print(client.state());
      Serial.println(" : retrying in 5 seconds]");
      delay(5000);
    }
  }
}