TgBots/Program.cs

using System;
using System.Data;
using System.Threading;
using System.Threading.Tasks;
using Telegram.Bot;
using Telegram.Bot.Types;
using Telegram.Bot.Types.Enums;
using Dapper;
using Npgsql;

class Program
{
    private static string botToken = "7814259349:AAEasTnDpX5s5PrQcR5ihI9pOsmp2Ocv-m0"; // Укажите токен вашего бота
    private static string connectionString = "Host=127.0.0.1;Port=5432;Database=telegram_bot;Username=postgres;Password=postgres";

    private static readonly TelegramBotClient botClient = new TelegramBotClient(botToken);

    static async Task Main(string[] args)
    {
        Console.WriteLine("Bot is running...");

        // Управление токеном завершения
        var cts = new CancellationTokenSource();
        Console.CancelKeyPress += (_, _) => cts.Cancel();

        botClient.StartReceiving(UpdateHandler, ErrorHandler, cancellationToken: cts.Token);

        Console.WriteLine("Press Ctrl+C to exit...");
        await Task.Delay(Timeout.Infinite, cts.Token);
    }

    private static async Task UpdateHandler(ITelegramBotClient bot, Update update, CancellationToken cancellationToken)
    {
        Console.WriteLine("Received an message");

        if (update.Type == UpdateType.Message && update.Message?.Text != null)
        {
            var message = update.Message;

            if (message.Text.StartsWith("/help"))
            {
                await bot.SendTextMessageAsync(message.Chat.Id, "Уйди. Попробуйте /reg", cancellationToken: cancellationToken);
            }
            else if (message.Text.StartsWith("/reg"))
            {
                await RegisterUser(message, cancellationToken);
            }
            else
            {
                await bot.SendTextMessageAsync(message.Chat.Id, "Неизвестная команда. Попробуйте /reg", cancellationToken: cancellationToken);
            }
        }
    }

    private static async Task RegisterUser(Message message, CancellationToken cancellationToken)
    {
        try
        {
            using (IDbConnection db = new NpgsqlConnection(connectionString))
            {
                string query = "INSERT INTO users (chat_id, user_id, user_name) VALUES (@ChatId, @UserId, @UserName) ON CONFLICT (user_id) DO NOTHING";

                var parameters = new
                {
                    ChatId = message.Chat.Id,
                    UserId = message.From.Id,
                    UserName = message.From.FirstName
                };

                int rowsAffected = await db.ExecuteAsync(query, parameters);

                if (rowsAffected > 0)
                {
                    await botClient.SendTextMessageAsync(message.Chat.Id, "Вы успешно зарегистрированы!", cancellationToken: cancellationToken);
                }
                else
                {
                    await botClient.SendTextMessageAsync(message.Chat.Id, "Вы уже зарегистрированы.", cancellationToken: cancellationToken);
                }
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error: {ex.Message}");
            await botClient.SendTextMessageAsync(message.Chat.Id, "Произошла ошибка при регистрации. Попробуйте позже.", cancellationToken: cancellationToken);
        }
    }

    private static Task ErrorHandler(ITelegramBotClient bot, Exception exception, CancellationToken cancellationToken)
    {
        Console.WriteLine($"Error: {exception.Message}");
        return Task.CompletedTask;
    }
}