telegram-bot/modules/UrlLimitations/MessageHandler.cs

using System;
using System.Linq;
using System.Threading.Tasks;
using BotFramework;
using BotFramework.Attributes;
using BotFramework.Setup;
using Kruzya.TelegramBot.Core.Cache;
using Kruzya.TelegramBot.Core.Extensions;
using Microsoft.Extensions.Logging;
using Telegram.Bot.Types;
using Telegram.Bot.Types.Enums;

namespace Kruzya.TelegramBot.UrlLimitations
{
    public class MessageHandler : BotEventHandler
    {
        protected ILogger Logger;
        protected MemoryCache<ChatMember, UInt16> ChatMembersCache;

        public MessageHandler(ILogger<MessageHandler> logger, MemoryCache<ChatMember, UInt16> chatMembersCache)
        {
            Logger = logger;
            ChatMembersCache = chatMembersCache;
        }

        [TextMessage(InChat.Public)]
        public async Task OnMessageReceived()
        {
            Logger.LogDebug($"Message received from {From.Id} in {Chat.Id}");

            UInt16 messageCount;
            var chatMember = ChatMember.From(Chat.Id, From.Id);
            if (!ChatMembersCache.TryGetValue(chatMember, out messageCount))
            {
                return;
            }

            if (messageCount > 10)
            {
                ChatMembersCache.SetValue(chatMember, 0, 0);
                return;
            }

            messageCount++;
            ChatMembersCache.SetValue(chatMember, messageCount);
            var message = RawUpdate.Message;
            if (message.Entities.Count(e => e.Type == MessageEntityType.Url || e.Type == MessageEntityType.TextLink) >
                0)
            {
                var targetChat = new ChatId(Chat.Id);
                await Bot.KickChatMemberAsync(new ChatId(Chat.Id), From.Id, DateTime.Now.AddDays(1));
                await Bot.DeleteMessageAsync(targetChat, message.MessageId);
                await Bot.SendTextMessageAsync(targetChat,
                    $"Member {From.ToHtml()} has been banned.\n<b>Reason</b>: <pre>Spam suspicion</pre>", ParseMode.Html);
            }
        }
    }
}