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

const int trigPin = 5;
const int echoPin = 18;
const float gama = 0.7;
const float rl10 = 50;
const int LED = 21;
//define sound speed in cm/uS
#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701
#define ldrPin 33

// WiFi
const char *ssid = "Wokwi-GUEST"; // Enter your Wi-Fi name
const char *password = "";  // Enter Wi-Fi password

// MQTT Broker
const char *mqtt_broker = "thingsboard.cloud";
const char *topic = "v1/devices/me/telemetry";
const int mqtt_port = 1883;
const char *access_Token = "LzJXkHkdpdKLiwZ2BQwP";

WiFiClient espClient;
PubSubClient client(espClient);


long duration;
float distanceCm;
float distanceInch;

void setup() {
  Serial.begin(115200); 
  pinMode(trigPin, OUTPUT); 
  pinMode(echoPin, INPUT);
  pinMode(21, OUTPUT);

  WiFi.begin(ssid, password);
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.println("Connecting to WiFi..");
    }
    Serial.println("Connected to the Wi-Fi network");
    //connecting to a mqtt broker
    client.setServer(mqtt_broker, mqtt_port);
    client.setCallback(callback);
    while (!client.connected()) {
        String client_id = "esp32-client-";
        client_id += String(WiFi.macAddress());
        Serial.printf("The client %s connects to the public MQTT broker\n", client_id.c_str());
        if (client.connect(client_id.c_str(), access_Token, NULL)) {
            Serial.println("Public EMQX MQTT broker connected");
        } else {
            Serial.print("failed with state ");
            Serial.print(client.state());
            delay(2000);
        }
    }

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

   client.loop();
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  
  // Calculate the distance
  distanceCm = duration * SOUND_SPEED/2;
  
  // Convert to inches
  distanceInch = distanceCm * CM_TO_INCH;
  
  // Prints the distance in the Serial Monitor
  int nilaiLDR = analogRead(ldrPin);
  nilaiLDR = map(nilaiLDR, 4095, 0, 1024, 0); //mengubah nilai pembacaan sensor LDR dari nilai ADC arduino menjadi nilai ADC ESP32
  float voltase = nilaiLDR / 1024.*5;
  float resistansi = 2000 * voltase / (1-voltase/5);
  float kecerahan = pow(rl10*1e3*pow(10,gama)/resistansi,(1/gama));
   kecerahan = map(kecerahan, 85168, 0, 500, 0);

  Serial.print("Kecerahan = ");
  Serial.println(kecerahan);
  Serial.print("Distance (cm): ");
  Serial.println(distanceCm);
  Serial.print("Distance (inch): ");
  Serial.println(distanceInch);

  String payload = "{\"kecerahan\": " ;
  payload += String(kecerahan);
  payload += ", \"distance\": ";
  payload += String(distanceCm);
  payload += "}";
  delay(1000);

  if (kecerahan >= 300 && distanceCm <= 30)
  {
    digitalWrite(21, HIGH);
  }
  else
  {
    digitalWrite(21, LOW);
  }

  client.publish(topic, payload.c_str());
  delay(50);
}