#include "WiFi.h"
#include <PubSubClient.h> 
#define LDR_PIN 34

// LDR Characteristics
const float GAMMA = 0.7;
const float RL10 = 50;


const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* server = "broker.mqttdashboard.com";
//char server[]="broker.netpie.io";

//char ClientID[]="971d5116-cc78-4491-a6fb-8899110e5885";
//char token[]="2n8yn1d8czPHge5Kx5FQ2sCqgqxxZ8Ka";
//char secret[]="7y~TYr0F~f-#IB80A82ba$K)f_di~~*o";


WiFiClient espClient;
PubSubClient client(espClient);
long lastMsg = 0;
char msg[50];
int value = 0;

void setup_wifi() {

  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  randomSeed(micros());
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("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() { // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Create a random client ID
    String clientId = "ESP8266Client-61070283";
    clientId += String(random(0xffff), HEX);
    // Attempt to connect
    if (client.connect(clientId.c_str())) {
      Serial.println("connected");
      // publish 
      //client.publish("@msg/project1", "hello world - 61070283");
      
      //client.subscribe("@msg/project1");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  pinMode(LDR_PIN, INPUT);
  setup_wifi();
  client.setServer(server, 1883);
  client.setCallback(callback);
}

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

  //convert to lux
  int analogValue = analogRead(LDR_PIN);
  float voltage = analogValue / 4095. * 5;
  float resistance = 2000 * voltage / (1 - voltage / 5);
  float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));
  int luxint = lux;

  //publish
  String val_str = String(luxint);
  char val_char[10];
  val_str.toCharArray(val_char, 10);

  client.publish("project1", val_char);
  Serial.print("Publish message at project1: ");
  Serial.println(val_char);

  delay(2000);
  
}