#include "WiFi.h"
#include <PubSubClient.h>
#include <ArduinoJson.h>
DynamicJsonDocument doc(1024);
const char* mqttServer = "broker.hivemq.com";
int port = 1883;
char clientId[50];
const char* ssid = "Wokwi-GUEST";
int channel = 6;
const char* password = "";
int ledPin = 19;
WiFiClient espClient;
PubSubClient client(espClient);

void setup()
{
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  Serial.print("Connecting to ");
  Serial.println(ssid);
  pinMode(ledPin, OUTPUT);
  // WiFi.begin(ssid, password, channel);/
  wifiConnect();
  client.setServer(mqttServer, port);
  // pinMode(analogPin, INPUT)
  client.setCallback(callback);

}
void loop()
{
  // put your main code here, to run repeatedly:
  delay(10); // this speeds up the simulation
  if (!client.connected())
  {
    mqttReconnect();
  }
  // else {
  //   client.publish("esp32-pub2", "data received");
  // }
  client.loop();
}
void wifiConnect() {
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
}
void mqttReconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    long r = random(1000);
    sprintf(clientId, "fcs-clientId-%ld", r);
    if (client.connect(clientId)) {
      Serial.print(clientId);
      Serial.println(" connected");
      client.subscribe("ESP32-sub2");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}
void callback(char* topic, byte* message, unsigned int length) {
  Serial.print("Message arrived on topic: ");
  Serial.print(topic);
  Serial.print(". Message: ");
  String stMessage;
  for (int i = 0; i < length; i++) {
    Serial.print((char)message[i]);
    stMessage += (char)message[i];
  }
  if (stMessage == "led_on") {
    digitalWrite(ledPin, HIGH);
  }
  else if (stMessage == "led_off") {
    digitalWrite(ledPin, LOW);
  }
}