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

const char* mqtt_server = "broker.hivemq.com";
const char* MQTT_ID = "f9f4c324-1184-4d0f-a33d-4a561f980ced";

int status = WL_IDLE_STATUS;
int Port = 1883;
int buzzer = 21;
const uint8_t ROWS = 4;
const uint8_t COLS = 4;

char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
uint8_t colPins[COLS] = { 16, 4, 2, 15 };
uint8_t rowPins[ROWS] = { 19, 18, 5, 17 };

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

WiFiClient wifiClient;
PubSubClient client(wifiClient);

String pass = "";

void setup() {
  Serial.begin(115200);
  pinMode(buzzer, OUTPUT);
  WIFIConnect();
  client.setServer(mqtt_server, Port);
  client.setCallback(callback);
}

void loop() {
  delay(10);
  if (!client.connected()) {
    MQTT_Reconnect();
  }
  client.loop();
  char key = keypad.getKey();
  if (key != NO_KEY) {
    if (key != '#') {
      pass = pass + key;
    } else {
      gui(pass);
      Serial.print(pass);
      pass = "";
    }
  }
}

void WIFIConnect() {
  Serial.println("Connecting to SSID: Wokwi-GUEST");
  WiFi.begin("Wokwi-GUEST", "");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.print("WiFi connected");
  Serial.print(", IP address: ");
  Serial.println(WiFi.localIP());
}

void MQTT_Reconnect() {
  while (!client.connected()) {
    if (client.connect(MQTT_ID)) {
      Serial.println("MQTT connected");
      client.subscribe("key");
    } 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.println("Message arrived on topic: " + String(topic));
  String stMessage;

  for (int i = 0; i < length; i++) {
    stMessage += (char)message[i];
  }
  Serial.println("Message: " + stMessage);

  if (stMessage == "on") {
    digitalWrite(buzzer, HIGH);
    delay(200);
    digitalWrite(buzzer, LOW);
  } else if (stMessage == "off") {
    for (int i = 0; i < 3; i++) {
      digitalWrite(buzzer, HIGH);
      delay(200);
      digitalWrite(buzzer, LOW);
    }
  }
}

void gui(String a) {
  client.publish("key", a.c_str());
}