#include <WiFi.h>
#include <PubSubClient.h>
#include <MD_MAX72xx.h>

#define HARDWARE_TYPE MD_MAX72XX::FC16_HW
#define MAX_DEVICES 4
#define CLK_PIN   13
#define DATA_PIN  14
#define CS_PIN    15

MD_MAX72XX mx = MD_MAX72XX(HARDWARE_TYPE, CS_PIN, MAX_DEVICES);

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

void setup() {
  mx.begin();
  mx.clear();
  WiFi.begin("Wokwi-GUEST", "");
  client.setServer("test.mosquitto.org", 1883);
  client.setCallback(callback);
}

void callback(char* topic, byte* message, unsigned int length) {
  String messageTemp;

  for (int i = 0; i < length; i++) {
    messageTemp += (char)message[i];
  }

  mx.print(messageTemp);
}

void reconnect() {
  while (!client.connected()) {
    if (client.connect("ESP32Client")) {
      client.subscribe("ThinkIOT/Matrix");
    } else {
      delay(5000);
    }
  }
}

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