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

#define BUZZERS_COUNT 4

uint8_t buzzer_pins[BUZZERS_COUNT] = {12, 14, 27, 26};

#define MQTT_SERVER "mqtt-dashboard.com"
#define MQTT_PORT 1883

WiFiClient   wifi_client;
PubSubClient mqtt_client(wifi_client);

#define I2C_ADDR    0x27
#define LCD_COLUMNS 20
#define LCD_LINES   4

LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);

void ring(uint8_t buzzer_idx) {
  tone(buzzer_pins[buzzer_idx], (buzzer_idx + 1) * 330, 5000);

  lcd.setCursor(0, 0);
  lcd.print("Buzer ");
  lcd.print(buzzer_idx + 1);
  lcd.print(" is ringing");

  lcd.setCursor(2, 1);
  lcd.print("Seconds remaining");

  for (int i = 5; i > 0; i--) {
    lcd.setCursor(0, 1);
    lcd.print(i);
    
    delay(1000);
  }

  lcd.clear();
}

void connect_to_mqtt() {
  while (!mqtt_client.connected()) {
    if (mqtt_client.connect("buzzer")) {
      Serial.println("Connected to MQTT Server!");
      mqtt_client.subscribe("bells");
    } else {
      delay(2000);
      Serial.println("Retrying...");
    }
  }
}

void on_callback(const char topic[], byte* payload, unsigned int length) {
  ring(payload[0] - 49);
}

void setup() {
  Serial.begin(19200);

  WiFi.mode(WIFI_STA);
  WiFi.begin("Wokwi-GUEST", "", 6);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }

  Serial.println("Connected to WiFi");

  mqtt_client.setServer(MQTT_SERVER, MQTT_PORT);
  mqtt_client.setCallback(on_callback);

  lcd.init();
  lcd.backlight();

  for (int i = 0; i < BUZZERS_COUNT; i++)
    pinMode(buzzer_pins[i], OUTPUT);

}

void loop() {
  if (!mqtt_client.connected()) {
    connect_to_mqtt();
  }


  mqtt_client.loop();

  delay(100);
}