telegram-bot/modules/ChatQuotes/Handler/Quote.cs

using BotFramework;
using BotFramework.Attributes;
using BotFramework.Enums;
using Telegram.Bot;
using Telegram.Bot.Types;

namespace West.TelegramBot.ChatQuotes.Handler;

public class Quote : BotEventHandler
{
    private readonly QuoteGeneratorService _quoteGenerator;

    public Quote(QuoteGeneratorService quoteGenerator)
    {
        _quoteGenerator = quoteGenerator;
    }

    [InChat(InChat.Public)]
    [Command("q", CommandParseMode.Both)]
    public async Task HandleQuote()
    {
        var msg = RawUpdate.Message;
        var replyToMessage = msg?.ReplyToMessage;
        if (msg == null || replyToMessage == null)
        {
            return;
        }

        var quoteImage = await _quoteGenerator.GenerateQuoteImage(replyToMessage);
        if (quoteImage == null)
        {
            return;
        }

        await Bot.SendStickerAsync(Chat.Id, new InputFile(quoteImage), 
            replyToMessageId: msg.MessageId);
    }
}