NadekoBot/NadekoBot.Core/Modules/Gambling/Common/CurrencyEvents/SneakyEvent.cs

using Discord;
using Discord.Commands;
using Discord.WebSocket;
using NadekoBot.Common;
using NadekoBot.Common.Collections;
using NadekoBot.Core.Services;
using System;
using System.Linq;
using System.Threading.Tasks;

namespace NadekoBot.Modules.Gambling.Common.CurrencyEvents
{
    public class SneakyEvent : CurrencyEvent
    {
        public event Action OnEnded;
        public string Code { get; private set; } = string.Empty;
        private readonly ConcurrentHashSet<ulong> _sneakyGameAwardedUsers = new ConcurrentHashSet<ulong>();

        private readonly char[] _sneakyGameStatusChars = Enumerable.Range(48, 10)
            .Concat(Enumerable.Range(65, 26))
            .Concat(Enumerable.Range(97, 26))
            .Select(x => (char)x)
            .ToArray();

        private readonly CurrencyService _cs;
        private readonly DiscordSocketClient _client;
        private readonly IBotConfigProvider _bc;
        private readonly int _length;

        public SneakyEvent(CurrencyService cs, DiscordSocketClient client,
            IBotConfigProvider bc, int len)
        {
            _cs = cs;
            _client = client;
            _bc = bc;
            _length = len;
        }

        public override async Task Start(IUserMessage msg, ICommandContext channel)
        {
            GenerateCode();

            //start the event
            _client.MessageReceived += SneakyGameMessageReceivedEventHandler;
            await _client.SetGameAsync($"type {Code} for " + _bc.BotConfig.CurrencyPluralName)
                .ConfigureAwait(false);
            await Task.Delay(_length * 1000).ConfigureAwait(false);
            await Stop().ConfigureAwait(false);
        }

        private void GenerateCode()
        {
            var rng = new NadekoRandom();

            for (var i = 0; i < 5; i++)
            {
                Code += _sneakyGameStatusChars[rng.Next(0, _sneakyGameStatusChars.Length)];
            }
        }

        public override async Task Stop()
        {
            try
            {
                _client.MessageReceived -= SneakyGameMessageReceivedEventHandler;
                Code = string.Empty;
                _sneakyGameAwardedUsers.Clear();
                await _client.SetGameAsync(null).ConfigureAwait(false);
            }
            catch { }
            finally
            {

                OnEnded?.Invoke();
            }
        }

        private Task SneakyGameMessageReceivedEventHandler(SocketMessage arg)
        {
            if (arg.Content == Code &&
                _sneakyGameAwardedUsers.Add(arg.Author.Id))
            {
                var _ = Task.Run(async () =>
                {
                    await _cs.AddAsync(arg.Author, "Sneaky Game Event", 100, false)
                        .ConfigureAwait(false);

                    try { await arg.DeleteAsync(new RequestOptions() { RetryMode = RetryMode.AlwaysFail }).ConfigureAwait(false); }
                    catch
                    {
                        // ignored
                    }
                });
            }

            return Task.CompletedTask;
        }
    }
}