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

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

#define mqtt_server "thingsboard.cloud"
#define mqtt_port 1883
#define mqtt_username "123"
#define mqtt_Password "12"
#define mqtt_deviceId "thimuthu"

#define LED_PIN 12 

WiFiClient wifi_client;
PubSubClient MQTT;

bool LED_Status = false;

void RPC_callback(char* topic, byte* payload, unsigned int length) {
  Serial.println("Msg Received");
  Serial.print("topic -");
  Serial.println(topic);

  Serial.print("payload -");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();

  int len = 0;
  while (topic[len] != 0) {
    len++;
  }
  int req_no;
  for (int i = 0; i < len; i++) {
    if (topic[len - 1 - i] == 0x2F) {
      req_no = atoi(topic + len - i);
      break;
    }
  }

  DynamicJsonDocument doc(1024);
  deserializeJson(doc, payload);

  String method = doc["method"];
  Serial.println(method);
  String reply;

  if (method == "getState") {
    reply = LED_Status ? "true" : "false";
  } else if (method == "setState") {
    String LEDvalue = doc["params"];
    if (LEDvalue == "true") {
      Serial.println("Led turn on");
      digitalWrite(LED_PIN, HIGH);
      LED_Status = true;
    } else {
      Serial.println("Led turn off");
      digitalWrite(LED_PIN, LOW);
      LED_Status = false;
    }
    reply = "true";
  } else {
    reply = "123456";
  }

  String PUB_topic = "v1/devices/me/rpc/response/" + String(req_no);
  MQTT.publish(PUB_topic.c_str(), reply.c_str());
}

void setup() {
  Serial.begin(115200);
  Serial.println("hello");
  pinMode(LED_PIN, OUTPUT);

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());

  MQTT.setClient(wifi_client);
  MQTT.setServer(mqtt_server, mqtt_port);

  if (MQTT.connect(mqtt_deviceId, mqtt_username, mqtt_Password)) {
    Serial.println("MQTT connected");
  }
  MQTT.setCallback(RPC_callback);
  if (MQTT.subscribe("v1/devices/me/rpc/request/+")) {
    Serial.println("Subscribed successfully");
  }
}

void loop() {
  MQTT.loop();
  
  // Blink LED every second
  if (LED_Status) {
    digitalWrite(LED_PIN, HIGH);
    delay(500);
    digitalWrite(LED_PIN, LOW);
    delay(500);
  }
}