@Service
public class Telebot {
    private final String API_KEY = "####################:####################################";
    private final Long GROUP_ID = -############;
    private TelegramBot bot;

    private final Map<String, BiConsumer<Long, String>> handlers = new ConcurrentHashMap<>();


    @PostConstruct
    private void postConstruct() {
        log.info("Staring telegram bot ...");

        //assign handlers
        handlers.put("/help", this::help);
        handlers.put("/echo", this::echo);
        handlers.put("/ping", this::ping);


        bot = new TelegramBot.Builder(API_KEY).build();

        bot.setUpdatesListener(updates -> {

            // process updates
            for (Update update : updates) {

                try {


                    Long chatId = update.message().chat().id();
                    String text = update.message().text();

                    if (isEmpty(trimAllWhitespace(text))) {
                        continue;
                    }

                    String[] commandArray = text.split("[ @]");
                    if (commandArray.length > 0) {

                        String command = commandArray[0];

                        if (handlers.containsKey(command)) {
                            String body = trimWhitespace(text.substring(command.length(), text.length()));

                            handlers.get(command).accept(chatId, body);
                        }
                    }

                }
                catch (Exception e) {
                    log.error("bot receive/handle message error: ", e);
                }
            }

            // return id of last processed update or confirm them all
            return UpdatesListener.CONFIRMED_UPDATES_ALL;
        });

    }

    // TELEGRAM BOT HANDLERS ===========================================



    private void help(Long chatId, String text) {

        String resp =
            "/help - this help" +
                "\n" + "/echo [text] - echo [text]" +
                "\n" + "/ping - echo-reply";

        SendResponse response = bot.execute(new SendMessage(chatId, resp));

    }

    private void echo(Long chatId, String text) {

        SendResponse response = bot.execute(new SendMessage(chatId, text));

    }

    private void ping(Long chatId, String text) {

        SendResponse response = bot.execute(new SendMessage(chatId, "pong"));
    }
}