Initial split of the modules

NadekoBot.Core/Modules/Administration/Common/Ratelimiter.cs

@@ -0,0 +1,59 @@
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Discord.WebSocket;
+using NadekoBot.Modules.Administration.Services;
+
+namespace NadekoBot.Modules.Administration.Common
+{
+    public class Ratelimiter
+    {
+        private readonly SlowmodeService _svc;
+
+        public class RatelimitedUser
+        {
+            public ulong UserId { get; set; }
+            public int MessageCount { get; set; } = 0;
+        }
+
+        public ulong ChannelId { get; set; }
+        public int MaxMessages { get; set; }
+        public int PerSeconds { get; set; }
+
+        public Ratelimiter(SlowmodeService svc)
+        {
+            _svc = svc;
+        }
+
+        public CancellationTokenSource CancelSource { get; set; } = new CancellationTokenSource();
+
+        public ConcurrentDictionary<ulong, RatelimitedUser> Users { get; set; } = new ConcurrentDictionary<ulong, RatelimitedUser>();
+
+        public bool CheckUserRatelimit(ulong id, ulong guildId, SocketGuildUser optUser)
+        {
+            if ((_svc.IgnoredUsers.TryGetValue(guildId, out HashSet<ulong> ignoreUsers) && ignoreUsers.Contains(id)) ||
+                (optUser != null && _svc.IgnoredRoles.TryGetValue(guildId, out HashSet<ulong> ignoreRoles) && optUser.Roles.Any(x => ignoreRoles.Contains(x.Id))))
+                return false;
+
+            var usr = Users.GetOrAdd(id, (key) => new RatelimitedUser() { UserId = id });
+            if (usr.MessageCount >= MaxMessages)
+            {
+                return true;
+            }
+            usr.MessageCount++;
+            var _ = Task.Run(async () =>
+            {
+                try
+                {
+                    await Task.Delay(PerSeconds * 1000, CancelSource.Token);
+                }
+                catch (OperationCanceledException) { }
+                usr.MessageCount--;
+            });
+            return false;
+        }
+    }
+}