telegram-bot/modules/ChatManagement/Handler/Rules.cs

using System.Threading.Tasks;
using BotFramework.Attributes;
using BotFramework.Enums;
using Kruzya.TelegramBot.Core.Data;
using Kruzya.TelegramBot.Core.Extensions;
using Telegram.Bot;
using Telegram.Bot.Exceptions;

namespace West.TelegramBot.ChatManagement.Handler
{
    class Rules : ManagementHandler
    {
        [Command(InChat.Public, "setrules", CommandParseMode.Both)]
        public async Task HandleSetRules()
        {
            var replyToMessage = Message?.ReplyToMessage;

            if (replyToMessage == null || !await Bot.IsUserAdminAsync(Chat, From)) return;

            var opt = await Db.UserValues.FindOrCreateOption(Chat.Id, "rulesMsgId");
            opt.SetValue(replyToMessage.MessageId);
            Db.Update(opt);
        }

        [Command(InChat.Public, "rules", CommandParseMode.Both)]
        public async Task HandleRules()
        {
            var opt = await Db.UserValues.FindOption(Chat.Id, "rulesMsgId");
            if (opt == null)
            {
                return;
            }

            try
            {
                await Bot.CopyMessageAsync(Chat.Id, Chat.Id, opt.GetValue<int>());
            }
            catch (ApiRequestException)
            {
                Db.UserValues.Remove(opt);
                throw;
            }
        }
        
        public Rules(CoreContext db) : base(db) {}
    }
}