#include <PubSubClient.h>
#include <WiFi.h>
#include <LiquidCrystal_I2C.h>
// WIFI config
const char* ssid = "Wokwi-GUEST";
const char* password =  "";
WiFiClient wifiClient;
// MQTT client config
const char* mqttServer = "broker.hivemq.com";
const int mqttPort = 1883;
const char* mqttUser = "";
const char* mqttPassword = "";
const char* topic_sub = "fah/Lab/counter";

PubSubClient mqttClient(wifiClient);
// LCD config
LiquidCrystal_I2C lcd(0x27, 16, 2);

void initLCD() {
  lcd.init();
  lcd.backlight();
  lcd.clear();
}
void displayLCD(int col, int row, String msg) {
  lcd.clear();
  lcd.setCursor(col, row);
  lcd.print(msg);
}

void setup_wifi() {
  // Start by connecting to a WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println();
  Serial.print("WiFi connected on ");
  Serial.print("IP address: ");
  Serial.print(WiFi.localIP());
  Serial.print(" MAC address: ");
  Serial.println(WiFi.macAddress());
}

void reconnectMQTT() {
  // Loop until we're reconnected
  char mqttinfo[80];
  char clientId[100] = "\0";
  snprintf (mqttinfo, 75, "Attempting MQTT connection at %s:%d( % s / % s)...", mqttServer, mqttPort, mqttUser, mqttPassword);
  while (!mqttClient.connected()) {
    Serial.println(mqttinfo);
    sprintf(clientId, "ESP32Client-%04X", random(0xffff));
    if (mqttClient.connect(clientId)) {
      Serial.println("...MQTT Broker connected...");
      mqttClient.subscribe(topic_sub);
    } else {
      Serial.print("failed, rc=");
      Serial.print(mqttClient.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void mqttCallback(char* topic, byte* payload, unsigned int length) {
  char payloadMsg[128];
  Serial.print("Message arrived in topic: ");
  Serial.print(topic);
  Serial.print(" Message:");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
    payloadMsg[i] = (char) payload[i];
  }
  payloadMsg[length] = '\0';
  Serial.println();
  Serial.println("-----------------------");
  doProcess(payloadMsg);
}

void doProcess(String rcvMsg) {
  displayLCD(6, 0, rcvMsg);
}

void setup() {
  Serial.begin(115200);
  initLCD();
  setup_wifi();
  // setup MQTT
  mqttClient.setServer(mqttServer, mqttPort);
  mqttClient.setCallback(mqttCallback);
}

void loop() {
  if (!mqttClient.connected()) {
    reconnectMQTT();
  }
  mqttClient.loop();
  delay(50);
}