#include <Keypad.h>
#include <LiquidCrystal_I2C.h>
#include <WiFi.h>
#include <PubSubClient.h>

#define ROW_NUM     4 // four rows
#define COLUMN_NUM  4 // four columns

char keys[ROW_NUM][COLUMN_NUM] = {
  {'1','2','3', 'A'},
  {'4','5','6', 'B'},
  {'7','8','9', 'C'},
  {'*','0','#', 'D'}
};

byte pin_rows[ROW_NUM]      = {12, 14, 27, 26}; // GPIO19, GPIO18, GPIO5, GPIO17 connect to the row pins
byte pin_column[COLUMN_NUM] = {25, 33, 32, 35};   // GPIO16, GPIO4, GPIO0, GPIO2 connect to the column pins

Keypad keypad = Keypad(makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM);
LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27, 16 column and 2 rows

int cursorColumn = 0;
String inputString = "";

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqttServer = "test.mosquitto.org";
const int mqttPort = 1883;
const char* mqttTopic = "password_topic";

WiFiClient espClient;
PubSubClient client(espClient);

void setup() {
  lcd.init(); // initialize the lcd
  lcd.backlight();

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to WiFi");

  client.setServer(mqttServer, mqttPort);
  client.setCallback(callback);

  while (!client.connected()) {
    Serial.println("Connecting to MQTT...");
    if (client.connect("password_client")) {
      Serial.println("Connected to MQTT");
    } else {
      Serial.print("Failed with state ");
      Serial.print(client.state());
      delay(2000);
    }
  }
}

void loop() {
  char key = keypad.getKey();

  if (key) {
    if (key == '*') {
      // Delete the previously typed characters
      if (inputString.length() > 0) {
        inputString.remove(inputString.length() - 1);
        cursorColumn--;
        lcd.setCursor(cursorColumn, 0);
        lcd.print(" ");
        lcd.setCursor(cursorColumn, 0);
      }
    } else if (key == '#') {
      // Check the entered password
      if (inputString == "4699") {
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Correct password");
        delay(2000);
        lcd.clear();
        publishMessage("Correct password");
      } else {
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Wrong password");
        delay(2000);
        lcd.clear();
        publishMessage("Wrong password");
      }

      inputString = "";
      cursorColumn = 0;
    } else {
      lcd.setCursor(cursorColumn, 0); // move cursor to (cursorColumn, 0)
      lcd.print(key);                 // print key at (cursorColumn, 0)
      inputString += key;
      cursorColumn++;                 // move cursor to next position

      if (cursorColumn == 16) {        // if reaching limit, clear LCD
        lcd.clear();
        cursorColumn = 0;
      }
    }
  }

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

void callback(char* topic, byte* payload, unsigned int length) {
  // Handle incoming MQTT messages, if needed
}

void reconnect() {
  while (!client.connected()) {
    Serial.println("Connecting to MQTT...");
    if (client.connect("password_client")) {
      Serial.println("Connected to MQTT");
      client.subscribe(mqttTopic);
    } else {
      Serial.print("Failed with state ");
      Serial.print(client.state());
      delay(2000);
    }
  }
}

void publishMessage(const char* message) {
  if (client.connected()) {
    client.publish(mqttTopic, message);
  }
}