Rewrote user and channel collections.

SharpChat/ChannelInfo.cs

@@ -1,7 +1,4 @@
-using System;
+namespace SharpChat {
-using System.Linq;
-
-namespace SharpChat {
     public class ChannelInfo {
         public string Name { get; }
         public string Password { get; set; }
@@ -12,6 +9,9 @@ namespace SharpChat {
         public bool HasPassword
             => !string.IsNullOrWhiteSpace(Password);
 
+        public bool IsPublic
+            => !IsTemporary && Rank < 1 && !HasPassword;
+
         public ChannelInfo(
             string name,
             string? password = null,
@@ -26,22 +26,10 @@ namespace SharpChat {
             OwnerId = ownerId;
         }
 
-        public bool NameEquals(string? name) {
-            return string.Equals(name, Name, StringComparison.InvariantCultureIgnoreCase);
-        }
-
         public bool IsOwner(UserInfo user) {
             return OwnerId > 0
                 && user != null
                 && OwnerId == user.UserId;
         }
-
-        public static bool CheckName(string name) {
-            return !string.IsNullOrWhiteSpace(name) && name.All(CheckNameChar);
-        }
-
-        public static bool CheckNameChar(char c) {
-            return char.IsLetter(c) || char.IsNumber(c) || c == '-' || c == '_';
-        }
     }
 }

SharpChat/ChannelsContext.cs

@@ -0,0 +1,123 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace SharpChat {
+    public class ChannelsContext {
+        private readonly List<ChannelInfo> Channels = new();
+
+        public ChannelInfo? MainChannel { get; private set; }
+        public int TotalCount { get; private set; }
+        public int PublicCount { get; private set; }
+
+        public ChannelInfo[] All => Channels.ToArray();
+
+        public ChannelInfo? Get(
+            string? name,
+            Func<string, string>? sanitise = null
+        ) {
+            if(string.IsNullOrWhiteSpace(name))
+                return null;
+
+            foreach(ChannelInfo info in Channels) {
+                string chanName = info.Name;
+                if(sanitise != null)
+                    chanName = sanitise(chanName);
+                if(!chanName.Equals(name, StringComparison.InvariantCultureIgnoreCase))
+                    continue;
+
+                return info;
+            }
+
+            return null;
+        }
+
+        public ChannelInfo[] GetMany(
+            string[]? names = null,
+            Func<string, string>? sanitiseName = null,
+            int minRank = 0,
+            bool? isPublic = null
+        ) {
+            List<ChannelInfo> chans = new();
+
+            names ??= Array.Empty<string>();
+            for(int i = 0; i < names.Length; ++i)
+                names[i] = names[i].ToLowerInvariant();
+
+            foreach(ChannelInfo info in Channels) {
+                if(info.Rank > minRank)
+                    continue;
+
+                if(isPublic != null && info.IsPublic != isPublic)
+                    continue;
+
+                if(names?.Length > 0) {
+                    string chanName = info.Name;
+                    if(sanitiseName != null)
+                        chanName = sanitiseName(chanName);
+
+                    bool match = false;
+                    foreach(string name in names)
+                        if(match = chanName.Equals(name, StringComparison.InvariantCultureIgnoreCase))
+                            break;
+
+                    if(!match)
+                        continue;
+                }
+
+                chans.Add(info);
+            }
+
+            return chans.ToArray();
+        }
+
+        public void Add(
+            ChannelInfo info,
+            bool forceMain = false,
+            Func<string, string>? sanitiseName = null
+        ) {
+            if(Get(info.Name, sanitiseName) != null)
+                throw new ArgumentException("A channel with this name has already been registered.", nameof(info));
+            if(string.IsNullOrWhiteSpace(info.Name))
+                throw new ArgumentException("Channel names may not be blank.", nameof(info));
+            // todo: there should be more restrictions on channel names
+
+            Channels.Add(info);
+
+            ++TotalCount;
+            if(info.IsPublic)
+                ++PublicCount;
+
+            if(forceMain || MainChannel == null)
+                MainChannel = info;
+        }
+
+        public void Remove(
+            ChannelInfo info,
+            Func<string, string>? sanitiseName = null
+        ) {
+            Remove(info.Name, sanitiseName);
+        }
+
+        public void Remove(
+            string? name,
+            Func<string, string>? sanitise = null
+        ) {
+            if(string.IsNullOrWhiteSpace(name))
+                return;
+
+            ChannelInfo? info = Get(name, sanitise);
+            if(info == null)
+                return;
+
+            Channels.Remove(info);
+
+            --TotalCount;
+            if(info.IsPublic)
+                --PublicCount;
+
+            if(MainChannel == info)
+                MainChannel = Channels.FirstOrDefault(c => !c.IsPublic);
+        }
+    }
+}

SharpChat/ChannelsUsersContext.cs

@@ -0,0 +1,257 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace SharpChat {
+    public class ChannelsUsersContext {
+        private readonly Dictionary<string, HashSet<long>> ChannelUsers = new();
+        private readonly Dictionary<long, HashSet<string>> UserChannels = new();
+        private readonly Dictionary<long, string> UserLastChannel = new();
+
+        public string GetUserLastChannel(long userId) {
+            return UserLastChannel.ContainsKey(userId)
+                ? UserLastChannel[userId]
+                : string.Empty;
+        }
+
+        public string GetUserLastChannel(UserInfo userInfo) {
+            return GetUserLastChannel(userInfo.UserId);
+        }
+
+        public void SetUserLastChannel(long userId, string channelName) {
+            channelName = channelName.ToLowerInvariant();
+            if(UserLastChannel.ContainsKey(userId))
+                UserLastChannel[userId] = channelName;
+            else
+                UserLastChannel.Add(userId, channelName);
+        }
+
+        public void SetUserLastChannel(UserInfo userInfo, ChannelInfo channelInfo) {
+            SetUserLastChannel(userInfo.UserId, channelInfo.Name);
+        }
+
+        public void DeleteUserLastChannel(long userId) {
+            if(UserLastChannel.ContainsKey(userId))
+                UserLastChannel.Remove(userId);
+        }
+
+        public void DeleteUserLastChannel(UserInfo userInfo) {
+            DeleteUserLastChannel(userInfo.UserId);
+        }
+
+        public bool IsUserLastChannel(long userId, string channelName) {
+            return !string.IsNullOrWhiteSpace(channelName)
+                && GetUserLastChannel(userId).Equals(channelName, StringComparison.InvariantCultureIgnoreCase);
+        }
+
+        public bool IsUserLastChannel(UserInfo userInfo, ChannelInfo channelInfo) {
+            return IsUserLastChannel(userInfo.UserId, channelInfo.Name);
+        }
+
+        public string[] GetUserChannelNames(long userId) {
+            if(!UserChannels.ContainsKey(userId))
+                return Array.Empty<string>();
+
+            return UserChannels[userId].ToArray();
+        }
+
+        public string[] GetUserChannelNames(UserInfo userInfo) {
+            return GetUserChannelNames(userInfo.UserId);
+        }
+
+        public long[] GetChannelUserIds(string channelName) {
+            channelName = channelName.ToLowerInvariant();
+            if(!ChannelUsers.ContainsKey(channelName))
+                return Array.Empty<long>();
+
+            return ChannelUsers[channelName].ToArray();
+        }
+
+        public long[] GetChannelUserIds(string channelName, Func<string, string> sanitise) {
+            foreach(KeyValuePair<string, HashSet<long>> kvp in ChannelUsers)
+                if(sanitise(kvp.Key).Equals(channelName, StringComparison.InvariantCultureIgnoreCase))
+                    return kvp.Value.ToArray();
+
+            return Array.Empty<long>();
+        }
+
+        public long[] GetChannelUserIds(ChannelInfo channelInfo) {
+            return GetChannelUserIds(channelInfo.Name);
+        }
+
+        public void Join(string channelName, long userId) {
+            channelName = channelName.ToLowerInvariant();
+            if(ChannelUsers.ContainsKey(channelName))
+                ChannelUsers[channelName].Add(userId);
+            else
+                ChannelUsers.Add(channelName, new HashSet<long> { userId });
+
+            if(UserChannels.ContainsKey(userId))
+                UserChannels[userId].Add(channelName);
+            else
+                UserChannels.Add(userId, new HashSet<string> { channelName });
+
+            SetUserLastChannel(userId, channelName);
+        }
+
+        public void Join(ChannelInfo channelInfo, UserInfo userInfo) {
+            Join(channelInfo.Name, userInfo.UserId);
+        }
+
+        public void Leave(string channelName, long userId) {
+            channelName = channelName.ToLowerInvariant();
+            if(ChannelUsers.ContainsKey(channelName)) {
+                if(ChannelUsers[channelName].Count < 2)
+                    ChannelUsers.Remove(channelName);
+                else
+                    ChannelUsers[channelName].Remove(userId);
+            }
+
+            if(UserChannels.ContainsKey(userId)) {
+                if(UserChannels[userId].Count < 2)
+                    UserChannels.Remove(userId);
+                else
+                    UserChannels[userId].Remove(channelName);
+            }
+
+            if(IsUserLastChannel(userId, channelName))
+                DeleteUserLastChannel(userId);
+        }
+
+        public void Leave(ChannelInfo channelInfo, UserInfo userInfo) {
+            Leave(channelInfo.Name, userInfo.UserId);
+        }
+
+        public bool Has(string channelName, long userId) {
+            channelName = channelName.ToLowerInvariant();
+            return ChannelUsers.ContainsKey(channelName)
+                && ChannelUsers[channelName].Contains(userId);
+        }
+
+        public bool Has(ChannelInfo channelInfo, UserInfo userInfo) {
+            return Has(channelInfo.Name, userInfo.UserId);
+        }
+
+        public long[] FilterUsers(string channelName, long[] userIds) {
+            if(userIds.Length < 1)
+                return userIds;
+
+            channelName = channelName.ToLowerInvariant();
+            if(!ChannelUsers.ContainsKey(channelName))
+                return Array.Empty<long>();
+
+            List<long> filtered = new();
+            HashSet<long> channelUserIds = ChannelUsers[channelName];
+            foreach(long userId in userIds)
+                if(channelUserIds.Contains(userId))
+                    filtered.Add(userId);
+
+            return filtered.ToArray();
+        }
+
+        public UserInfo[] FilterUsers(ChannelInfo channelInfo, UserInfo[] userInfos) {
+            if(userInfos.Length < 1)
+                return userInfos;
+
+            long[] filteredIds = FilterUsers(channelInfo.Name, userInfos.Select(u => u.UserId).ToArray());
+            if(filteredIds.Length < 1)
+                return Array.Empty<UserInfo>();
+
+            return userInfos.Where(u => filteredIds.Contains(u.UserId)).ToArray();
+        }
+
+        public bool HasUsers(string channelName, long[] userIds) {
+            return FilterUsers(channelName, userIds).SequenceEqual(userIds);
+        }
+
+        public bool HasUsers(ChannelInfo channelInfo, UserInfo[] userInfos) {
+            return HasUsers(channelInfo.Name, userInfos.Select(u => u.UserId).ToArray());
+        }
+
+        public string[] FilterChannels(long userId, string[] channelNames) {
+            if(channelNames.Length < 1)
+                return channelNames;
+
+            if(!UserChannels.ContainsKey(userId))
+                return Array.Empty<string>();
+
+            List<string> filtered = new();
+            HashSet<string> userChannelNames = UserChannels[userId];
+            foreach(string channelName in userChannelNames)
+                if(userChannelNames.Contains(channelName))
+                    filtered.Add(channelName);
+
+            return filtered.ToArray();
+        }
+
+        public ChannelInfo[] FilterChannels(UserInfo userInfo, ChannelInfo[] channelInfos) {
+            if(channelInfos.Length < 1)
+                return channelInfos;
+
+            string[] filteredNames = FilterChannels(userInfo.UserId, channelInfos.Select(c => c.Name).ToArray());
+            if(filteredNames.Length < 1)
+                return Array.Empty<ChannelInfo>();
+
+            return channelInfos.Where(c => filteredNames.Contains(c.Name.ToLowerInvariant())).ToArray();
+        }
+
+        public bool HasChannels(long userId, string[] channelNames) {
+            if(!UserChannels.ContainsKey(userId))
+                return false;
+
+            HashSet<string> userChannelNames = UserChannels[userId];
+            foreach(string channelName in channelNames)
+                if(!userChannelNames.Contains(channelName.ToLowerInvariant()))
+                    return false;
+
+            return true;
+        }
+
+        public bool HasChannels(UserInfo userInfo, ChannelInfo[] channelInfos) {
+            return HasChannels(userInfo.UserId, channelInfos.Select(c => c.Name).ToArray());
+        }
+
+        public void DeleteUser(long userId) {
+            if(!UserChannels.ContainsKey(userId))
+                return;
+
+            HashSet<string> channelNames = UserChannels[userId];
+            UserChannels.Remove(userId);
+            DeleteUserLastChannel(userId);
+
+            foreach(string channelName in channelNames) {
+                if(!ChannelUsers.ContainsKey(channelName))
+                    continue;
+
+                ChannelUsers[channelName].Remove(userId);
+            }
+        }
+
+        public void DeleteUser(UserInfo userInfo) {
+            DeleteUser(userInfo.UserId);
+        }
+
+        public void DeleteChannel(string channelName) {
+            channelName = channelName.ToLowerInvariant();
+            if(!ChannelUsers.ContainsKey(channelName))
+                return;
+
+            HashSet<long> userIds = ChannelUsers[channelName];
+            ChannelUsers.Remove(channelName);
+
+            foreach(long userId in userIds) {
+                if(!UserChannels.ContainsKey(userId))
+                    continue;
+
+                UserChannels[userId].Remove(channelName);
+
+                if(IsUserLastChannel(userId, channelName))
+                    DeleteUserLastChannel(userId);
+            }
+        }
+
+        public void DeleteChannel(ChannelInfo channelInfo) {
+            DeleteChannel(channelInfo.Name);
+        }
+    }
+}

SharpChat/ChatContext.cs

@@ -9,17 +9,14 @@ using System.Threading;
 
 namespace SharpChat {
     public class ChatContext {
-        public record ChannelUserAssoc(long UserId, string ChannelName);
-
         public readonly SemaphoreSlim ContextAccess = new(1, 1);
 
-        public Dictionary<string, ChannelInfo> Channels { get; } = new();
+        public ChannelsContext Channels { get; } = new();
         public List<ConnectionInfo> Connections { get; } = new();
-        public Dictionary<long, UserInfo> Users { get; } = new();
+        public UsersContext Users { get; } = new();
         public IEventStorage Events { get; }
-        public HashSet<ChannelUserAssoc> ChannelUsers { get; } = new();
+        public ChannelsUsersContext ChannelsUsers { get; } = new();
         public Dictionary<long, RateLimiter> UserRateLimiters { get; } = new();
-        public Dictionary<long, ChannelInfo> UserLastChannel { get; } = new();
 
         public ChatContext(IEventStorage evtStore) {
             Events = evtStore;
@@ -41,7 +38,7 @@ namespace SharpChat {
                     if(targetIds.Length != 2)
                         return;
 
-                    UserInfo[] users = Users.Where(kvp => targetIds.Contains(kvp.Key)).Select(kvp => kvp.Value).ToArray();
+                    UserInfo[] users = Users.GetMany(targetIds);
                     UserInfo? target = users.FirstOrDefault(u => u.UserId != mce.SenderId);
                     if(target == null)
                         return;
@@ -51,12 +48,12 @@ namespace SharpChat {
                             mce.MessageId,
                             DateTimeOffset.Now,
                             mce.SenderId,
-                            mce.SenderId == user.UserId ? $"{target.LegacyName} {mce.MessageText}" : mce.MessageText,
+                            mce.SenderId == user.UserId ? $"{SockChatUtility.GetUserName(target)} {mce.MessageText}" : mce.MessageText,
                             mce.IsAction,
                             true
                         ));
                 } else {
-                    ChannelInfo? channel = Channels.Values.FirstOrDefault(c => c.NameEquals(mce.ChannelName));
+                    ChannelInfo? channel = Channels.Get(mce.ChannelName, SockChatUtility.SanitiseChannelName);
                     if(channel != null)
                         SendTo(channel, new MessageAddPacket(
                             mce.MessageId,
@@ -92,7 +89,7 @@ namespace SharpChat {
             if(removed > 0)
                 Logger.Write($"Removed {removed} nuked connections from the list.");
 
-            foreach(UserInfo user in Users.Values)
+            foreach(UserInfo user in Users.All)
                 if(!Connections.Any(conn => conn.User == user)) {
                     HandleDisconnect(user, UserDisconnectReason.TimeOut);
                     Logger.Write($"Timed out {user} (no more connections).");
@@ -108,28 +105,12 @@ namespace SharpChat {
             }
         }
 
-        public bool IsInChannel(UserInfo? user, ChannelInfo? channel) {
-            return user != null
-                && channel != null
-                && ChannelUsers.Contains(new ChannelUserAssoc(user.UserId, channel.Name));
-        }
-
-        public string[] GetUserChannelNames(UserInfo user) {
-            return ChannelUsers.Where(cu => cu.UserId == user.UserId).Select(cu => cu.ChannelName).ToArray();
-        }
-
         public ChannelInfo[] GetUserChannels(UserInfo user) {
-            string[] names = GetUserChannelNames(user);
+            return Channels.GetMany(ChannelsUsers.GetUserChannelNames(user));
-            return Channels.Values.Where(c => names.Any(n => c.NameEquals(n))).ToArray();
-        }
-
-        public long[] GetChannelUserIds(ChannelInfo channel) {
-            return ChannelUsers.Where(cu => channel.NameEquals(cu.ChannelName)).Select(cu => cu.UserId).ToArray();
         }
 
         public UserInfo[] GetChannelUsers(ChannelInfo channel) {
-            long[] targetIds = GetChannelUserIds(channel);
+            return Users.GetMany(ChannelsUsers.GetChannelUserIds(channel));
-            return Users.Values.Where(u => targetIds.Contains(u.UserId)).ToArray();
         }
 
         public void UpdateUser(
@@ -192,11 +173,11 @@ namespace SharpChat {
 
             if(hasChanged) {
                 if(previousName != null)
-                    SendToUserChannels(user, new UserUpdateNotificationPacket(previousName, user.LegacyNameWithStatus));
+                    SendToUserChannels(user, new UserUpdateNotificationPacket(previousName, SockChatUtility.GetUserNameWithStatus(user)));
 
                 SendToUserChannels(user, new UserUpdatePacket(
                     user.UserId,
-                    user.LegacyNameWithStatus,
+                    SockChatUtility.GetUserNameWithStatus(user),
                     user.Colour,
                     user.Rank,
                     user.Permissions
@@ -222,10 +203,10 @@ namespace SharpChat {
         public void HandleChannelEventLog(string channelName, Action<IServerPacket> handler) {
             foreach(StoredEventInfo msg in Events.GetChannelEventLog(channelName))
                 handler(msg.Type switch {
-                    "user:connect" => new UserConnectLogPacket(msg.Created, msg.Sender?.LegacyName ?? string.Empty),
+                    "user:connect" => new UserConnectLogPacket(msg.Created, msg.Sender == null ? string.Empty : SockChatUtility.GetUserName(msg.Sender)),
                     "user:disconnect" => new UserDisconnectLogPacket(
                         msg.Created,
-                        msg.Sender?.LegacyNameWithStatus ?? string.Empty,
+                        msg.Sender == null ? string.Empty : SockChatUtility.GetUserNameWithStatus(msg.Sender),
                         (UserDisconnectReason)msg.Data.RootElement.GetProperty("reason").GetByte()
                     ),
                     _ => new MessagePopulatePacket(msg),
@@ -233,11 +214,11 @@ namespace SharpChat {
         }
 
         public void HandleJoin(UserInfo user, ChannelInfo chan, ConnectionInfo conn, int maxMsgLength) {
-            if(!IsInChannel(user, chan)) {
+            if(!ChannelsUsers.Has(chan, user)) {
                 SendTo(chan, new UserConnectPacket(
                     DateTimeOffset.Now,
                     user.UserId,
-                    user.LegacyNameWithStatus,
+                    SockChatUtility.GetUserNameWithStatus(user),
                     user.Colour,
                     user.Rank,
                     user.Permissions
@@ -247,7 +228,7 @@ namespace SharpChat {
 
             conn.Send(new AuthSuccessPacket(
                 user.UserId,
-                user.LegacyNameWithStatus,
+                SockChatUtility.GetUserNameWithStatus(user),
                 user.Colour,
                 user.Rank,
                 user.Permissions,
@@ -255,32 +236,42 @@ namespace SharpChat {
                 maxMsgLength
             ));
             conn.Send(new UsersPopulatePacket(GetChannelUsers(chan).Except(new[] { user }).Select(
-                user => new UsersPopulatePacket.ListEntry(user.UserId, user.LegacyNameWithStatus, user.Colour, user.Rank, user.Permissions, true)
+                user => new UsersPopulatePacket.ListEntry(
+                    user.UserId,
+                    SockChatUtility.GetUserNameWithStatus(user),
+                    user.Colour,
+                    user.Rank,
+                    user.Permissions,
+                    true
+                )
             ).OrderByDescending(user => user.Rank).ToArray()));
 
             HandleChannelEventLog(chan.Name, p => conn.Send(p));
 
-            conn.Send(new ChannelsPopulatePacket(Channels.Values.Where(c => c.Rank <= user.Rank).Select(
+            conn.Send(new ChannelsPopulatePacket(Channels.GetMany(isPublic: true, minRank: user.Rank).Select(
                 channel => new ChannelsPopulatePacket.ListEntry(channel.Name, channel.HasPassword, channel.IsTemporary)
             ).ToArray()));
 
-            Users.Add(user.UserId, user);
+            if(Users.Get(userId: user.UserId) == null)
+                Users.Add(user);
 
-            ChannelUsers.Add(new ChannelUserAssoc(user.UserId, chan.Name));
+            ChannelsUsers.Join(chan.Name, user.UserId);
-            UserLastChannel[user.UserId] = chan;
         }
 
         public void HandleDisconnect(UserInfo user, UserDisconnectReason reason = UserDisconnectReason.Leave) {
             UpdateUser(user, status: UserStatus.Offline);
             Users.Remove(user.UserId);
-            UserLastChannel.Remove(user.UserId);
 
             ChannelInfo[] channels = GetUserChannels(user);
+            ChannelsUsers.DeleteUser(user);
 
             foreach(ChannelInfo chan in channels) {
-                ChannelUsers.Remove(new ChannelUserAssoc(user.UserId, chan.Name));
+                SendTo(chan, new UserDisconnectPacket(
-
+                    DateTimeOffset.Now,
-                SendTo(chan, new UserDisconnectPacket(DateTimeOffset.Now, user.UserId, user.LegacyNameWithStatus, reason));
+                    user.UserId,
+                    SockChatUtility.GetUserNameWithStatus(user),
+                    reason
+                ));
                 Events.AddEvent("user:disconnect", user, chan, new { reason = (int)reason }, StoredEventFlags.Log);
 
                 if(chan.IsTemporary && chan.IsOwner(user))
@@ -289,7 +280,7 @@ namespace SharpChat {
         }
 
         public void SwitchChannel(UserInfo user, ChannelInfo chan, string password) {
-            if(UserLastChannel.TryGetValue(user.UserId, out ChannelInfo? ulc) && chan == ulc) {
+            if(ChannelsUsers.IsUserLastChannel(user, chan)) {
                 ForceChannel(user);
                 return;
             }
@@ -312,29 +303,44 @@ namespace SharpChat {
         }
 
         public void ForceChannelSwitch(UserInfo user, ChannelInfo chan) {
-            if(!Channels.ContainsValue(chan))
+            ChannelInfo? oldChan = Channels.Get(ChannelsUsers.GetUserLastChannel(user));
-                return;
 
-            ChannelInfo oldChan = UserLastChannel[user.UserId];
+            if(oldChan != null) {
+                SendTo(oldChan, new UserChannelLeavePacket(user.UserId));
+                Events.AddEvent("chan:leave", user, oldChan, flags: StoredEventFlags.Log);
+            }
 
-            SendTo(oldChan, new UserChannelLeavePacket(user.UserId));
+            SendTo(chan, new UserChannelJoinPacket(
-            Events.AddEvent("chan:leave", user, oldChan, flags: StoredEventFlags.Log);
+                user.UserId,
-            SendTo(chan, new UserChannelJoinPacket(user.UserId, user.LegacyNameWithStatus, user.Colour, user.Rank, user.Permissions));
+                SockChatUtility.GetUserNameWithStatus(user),
-            Events.AddEvent("chan:join", user, oldChan, flags: StoredEventFlags.Log);
+                user.Colour,
+                user.Rank,
+                user.Permissions
+            ));
+
+            if(oldChan != null)
+                Events.AddEvent("chan:join", user, oldChan, flags: StoredEventFlags.Log);
 
             SendTo(user, new ContextClearPacket(ContextClearPacket.ClearMode.MessagesUsers));
             SendTo(user, new UsersPopulatePacket(GetChannelUsers(chan).Except(new[] { user }).Select(
-                user => new UsersPopulatePacket.ListEntry(user.UserId, user.LegacyNameWithStatus, user.Colour, user.Rank, user.Permissions, true)
+                user => new UsersPopulatePacket.ListEntry(
+                    user.UserId,
+                    SockChatUtility.GetUserNameWithStatus(user),
+                    user.Colour,
+                    user.Rank,
+                    user.Permissions,
+                    true
+                )
             ).OrderByDescending(u => u.Rank).ToArray()));
 
             HandleChannelEventLog(chan.Name, p => SendTo(user, p));
             ForceChannel(user, chan);
 
-            ChannelUsers.Remove(new ChannelUserAssoc(user.UserId, oldChan.Name));
+            if(oldChan != null)
-            ChannelUsers.Add(new ChannelUserAssoc(user.UserId, chan.Name));
+                ChannelsUsers.Leave(oldChan, user);
-            UserLastChannel[user.UserId] = chan;
+            ChannelsUsers.Join(chan, user);
 
-            if(oldChan.IsTemporary && oldChan.IsOwner(user))
+            if(oldChan != null && oldChan.IsTemporary && oldChan.IsOwner(user))
                 RemoveChannel(oldChan);
         }
 
@@ -346,22 +352,21 @@ namespace SharpChat {
 
         public void SendTo(UserInfo user, IServerPacket packet) {
             foreach(ConnectionInfo conn in Connections)
-                if(conn.IsAlive && conn.User == user)
+                if(conn.IsAuthed && conn.User!.UserId == user.UserId)
                     conn.Send(packet);
         }
 
         public void SendTo(ChannelInfo channel, IServerPacket packet) {
-            // might be faster to grab the users first and then cascade into that SendTo
+            long[] userIds = ChannelsUsers.GetChannelUserIds(channel);
-            IEnumerable<ConnectionInfo> conns = Connections.Where(c => c.IsAuthed && IsInChannel(c.User, channel));
+            foreach(ConnectionInfo conn in Connections)
-            foreach(ConnectionInfo conn in conns)
+                if(conn.IsAuthed && userIds.Contains(conn.User!.UserId))
-                conn.Send(packet);
+                    conn.Send(packet);
         }
 
         public void SendToUserChannels(UserInfo user, IServerPacket packet) {
-            IEnumerable<ChannelInfo> chans = Channels.Values.Where(c => IsInChannel(user, c));
+            ChannelInfo[] chans = GetUserChannels(user);
-            IEnumerable<ConnectionInfo> conns = Connections.Where(conn => conn.IsAuthed && ChannelUsers.Any(cu => cu.UserId == conn.User?.UserId && chans.Any(chan => chan.NameEquals(cu.ChannelName))));
+            foreach(ChannelInfo chan in chans)
-            foreach(ConnectionInfo conn in conns)
+                SendTo(chan, packet);
-                conn.Send(packet);
         }
 
         public IPAddress[] GetRemoteAddresses(UserInfo user) {
@@ -369,10 +374,9 @@ namespace SharpChat {
         }
 
         public void ForceChannel(UserInfo user, ChannelInfo? chan = null) {
-            if(chan == null && !UserLastChannel.TryGetValue(user.UserId, out chan))
+            chan ??= Channels.Get(ChannelsUsers.GetUserLastChannel(user));
-                throw new ArgumentException("no channel???");
+            if(chan != null)
-
+                SendTo(user, new UserChannelForceJoinPacket(chan.Name));
-            SendTo(user, new UserChannelForceJoinPacket(chan.Name));
         }
 
         public void UpdateChannel(
@@ -381,9 +385,6 @@ namespace SharpChat {
             int? minRank = null,
             string? password = null
         ) {
-            if(!Channels.ContainsValue(channel))
-                throw new ArgumentException("Provided channel is not registered with this manager.", nameof(channel));
-
             string prevName = channel.Name;
 
             if(temporary.HasValue)
@@ -396,21 +397,21 @@ namespace SharpChat {
                 channel.Password = password;
 
             // TODO: Users that no longer have access to the channel/gained access to the channel by the rank change should receive delete and create packets respectively
-            foreach(UserInfo user in Users.Values.Where(u => u.Rank >= channel.Rank)) {
+            // the server currently doesn't keep track of what channels a user is already aware of so can't really simulate this yet.
+            foreach(UserInfo user in Users.GetMany(minRank: channel.Rank))
                 SendTo(user, new ChannelUpdatePacket(prevName, channel.Name, channel.HasPassword, channel.IsTemporary));
-            }
         }
 
         public void RemoveChannel(ChannelInfo channel) {
-            if(channel == null || !Channels.Any())
+            if(channel == null || Channels.PublicCount > 1)
                 return;
 
-            ChannelInfo? defaultChannel = Channels.Values.FirstOrDefault();
+            ChannelInfo? defaultChannel = Channels.MainChannel;
             if(defaultChannel == null)
                 return;
 
             // Remove channel from the listing
-            Channels.Remove(channel.Name);
+            Channels.Remove(channel);
 
             // Move all users back to the main channel
             // TODO: Replace this with a kick. SCv2 supports being in 0 channels, SCv1 should force the user back to DefaultChannel.
@@ -418,7 +419,7 @@ namespace SharpChat {
                 SwitchChannel(user, defaultChannel, string.Empty);
 
             // Broadcast deletion of channel
-            foreach(UserInfo user in Users.Values.Where(u => u.Rank >= channel.Rank))
+            foreach(UserInfo user in Users.GetMany(minRank: channel.Rank))
                 SendTo(user, new ChannelDeletePacket(channel.Name));
         }
     }

SharpChat/Commands/ChannelCreateCommand.cs

@@ -33,12 +33,12 @@ namespace SharpChat.Commands {
 
             string createChanName = string.Join('_', ctx.Args.Skip(createChanHasHierarchy ? 1 : 0));
 
-            if(!ChannelInfo.CheckName(createChanName)) {
+            if(!SockChatUtility.CheckChannelName(createChanName)) {
                 ctx.Chat.SendTo(ctx.User, new ChannelNameFormatErrorPacket());
                 return;
             }
 
-            if(ctx.Chat.Channels.Values.Any(c => c.NameEquals(createChanName))) {
+            if(ctx.Chat.Channels.Get(createChanName, SockChatUtility.SanitiseChannelName) != null) {
                 ctx.Chat.SendTo(ctx.User, new ChannelNameInUseErrorPacket(createChanName));
                 return;
             }
@@ -50,8 +50,8 @@ namespace SharpChat.Commands {
                 ownerId: ctx.User.UserId
             );
 
-            ctx.Chat.Channels.Add(createChan.Name, createChan);
+            ctx.Chat.Channels.Add(createChan, sanitiseName: SockChatUtility.SanitiseChannelName);
-            foreach(UserInfo ccu in ctx.Chat.Users.Values.Where(u => u.Rank >= ctx.Channel.Rank))
+            foreach(UserInfo ccu in ctx.Chat.Users.GetMany(minRank: ctx.Channel.Rank))
                 ctx.Chat.SendTo(ccu, new ChannelCreatePacket(
                     ctx.Channel.Name,
                     ctx.Channel.HasPassword,

SharpChat/Commands/ChannelDeleteCommand.cs

@@ -17,7 +17,7 @@ namespace SharpChat.Commands {
             }
 
             string delChanName = string.Join('_', ctx.Args);
-            ChannelInfo? delChan = ctx.Chat.Channels.Values.FirstOrDefault(c => c.NameEquals(delChanName));
+            ChannelInfo? delChan = ctx.Chat.Channels.Get(delChanName, SockChatUtility.SanitiseChannelName);
 
             if(delChan == null) {
                 ctx.Chat.SendTo(ctx.User, new ChannelNotFoundErrorPacket(delChanName));

SharpChat/Commands/ChannelJoinCommand.cs

@@ -9,7 +9,7 @@ namespace SharpChat.Commands {
 
         public void Dispatch(UserCommandContext ctx) {
             string joinChanStr = ctx.Args.FirstOrDefault() ?? string.Empty;
-            ChannelInfo? joinChan = ctx.Chat.Channels.Values.FirstOrDefault(c => c.NameEquals(joinChanStr));
+            ChannelInfo? joinChan = ctx.Chat.Channels.Get(joinChanStr, SockChatUtility.SanitiseChannelName);
 
             if(joinChan == null) {
                 ctx.Chat.SendTo(ctx.User, new ChannelNotFoundErrorPacket(joinChanStr));

SharpChat/Commands/KickBanCommand.cs

@@ -30,13 +30,14 @@ namespace SharpChat.Commands {
             int banReasonIndex = 1;
             UserInfo? banUser = null;
 
-            if(string.IsNullOrEmpty(banUserTarget) || (banUser = ctx.Chat.Users.Values.FirstOrDefault(u => u.NameEquals(banUserTarget))) == null) {
+            (string name, UsersContext.NameTarget target) = SockChatUtility.ExplodeUserName(banUserTarget);
+            if(string.IsNullOrEmpty(name) || (banUser = ctx.Chat.Users.Get(name: name, nameTarget: target)) == null) {
                 ctx.Chat.SendTo(ctx.User, new UserNotFoundErrorPacket(banUserTarget));
                 return;
             }
 
             if(!ctx.User.IsSuper && banUser.Rank >= ctx.User.Rank && banUser != ctx.User) {
-                ctx.Chat.SendTo(ctx.User, new KickBanNotAllowedErrorPacket(banUser.LegacyName));
+                ctx.Chat.SendTo(ctx.User, new KickBanNotAllowedErrorPacket(SockChatUtility.GetUserName(banUser)));
                 return;
             }
 
@@ -66,7 +67,7 @@ namespace SharpChat.Commands {
                 MisuzuBanInfo? fbi = await Misuzu.CheckBanAsync(userId, userIp);
 
                 if(fbi != null && fbi.IsBanned && !fbi.HasExpired) {
-                    ctx.Chat.SendTo(ctx.User, new KickBanNotAllowedErrorPacket(banUser.LegacyName));
+                    ctx.Chat.SendTo(ctx.User, new KickBanNotAllowedErrorPacket(SockChatUtility.GetUserName(banUser)));
                     return;
                 }
 

SharpChat/Commands/MessageWhisperCommand.cs

@@ -17,7 +17,8 @@ namespace SharpChat.Commands {
             }
 
             string whisperUserStr = ctx.Args.FirstOrDefault() ?? string.Empty;
-            UserInfo? whisperUser = ctx.Chat.Users.Values.FirstOrDefault(u => u.NameEquals(whisperUserStr));
+            (string name, UsersContext.NameTarget target) = SockChatUtility.ExplodeUserName(whisperUserStr);
+            UserInfo? whisperUser = ctx.Chat.Users.Get(name: name, nameTarget: target);
 
             if(whisperUser == null) {
                 ctx.Chat.SendTo(ctx.User, new UserNotFoundErrorPacket(whisperUserStr));

SharpChat/Commands/PardonAddressCommand.cs

@@ -1,6 +1,5 @@
 using SharpChat.Misuzu;
 using SharpChat.Packet;
-using System;
 using System.Linq;
 using System.Net;
 using System.Threading.Tasks;

SharpChat/Commands/PardonUserCommand.cs

@@ -1,6 +1,5 @@
 using SharpChat.Misuzu;
 using SharpChat.Packet;
-using System;
 using System.Linq;
 using System.Threading.Tasks;
 
@@ -31,10 +30,11 @@ namespace SharpChat.Commands {
                 return;
             }
 
-            UserInfo? unbanUser = ctx.Chat.Users.Values.FirstOrDefault(u => u.NameEquals(unbanUserTarget));
+            (string name, UsersContext.NameTarget target) = SockChatUtility.ExplodeUserName(unbanUserTarget);
+            UserInfo? unbanUser = ctx.Chat.Users.Get(name: name, nameTarget: target);
             if(unbanUser == null && long.TryParse(unbanUserTarget, out long unbanUserId)) {
                 unbanUserTargetIsName = false;
-                unbanUser = ctx.Chat.Users.Values.FirstOrDefault(u => u.UserId == unbanUserId);
+                unbanUser = ctx.Chat.Users.Get(unbanUserId);
             }
 
             if(unbanUser != null)

SharpChat/Commands/UserAFKCommand.cs

@@ -1,5 +1,4 @@
-using SharpChat.Packet;
+using System.Linq;
-using System.Linq;
 
 namespace SharpChat.Commands {
     public class UserAFKCommand : IUserCommand {

SharpChat/Commands/UserNickCommand.cs

@@ -19,7 +19,7 @@ namespace SharpChat.Commands {
             int offset = 0;
 
             if(setOthersNick && long.TryParse(ctx.Args.FirstOrDefault(), out long targetUserId) && targetUserId > 0) {
-                targetUser = ctx.Chat.Users.Values.FirstOrDefault(u => u.UserId == targetUserId);
+                targetUser = ctx.Chat.Users.Get(targetUserId);
                 ++offset;
             }
 
@@ -42,7 +42,7 @@ namespace SharpChat.Commands {
             else if(string.IsNullOrEmpty(nickStr))
                 nickStr = string.Empty;
 
-            if(!string.IsNullOrWhiteSpace(nickStr) && ctx.Chat.Users.Values.Any(u => u.NameEquals(nickStr))) {
+            if(!string.IsNullOrWhiteSpace(nickStr) && ctx.Chat.Users.Get(name: nickStr, nameTarget: UsersContext.NameTarget.UserAndNickName) != null) {
                 ctx.Chat.SendTo(ctx.User, new UserNameInUseErrorPacket(nickStr));
                 return;
             }

SharpChat/Commands/WhoCommand.cs

@@ -12,13 +12,13 @@ namespace SharpChat.Commands {
 
             if(string.IsNullOrEmpty(channelName)) {
                 ctx.Chat.SendTo(ctx.User, new WhoServerResponsePacket(
-                    ctx.Chat.Users.Values.Select(u => u.LegacyName).ToArray(),
+                    ctx.Chat.Users.All.Select(u => SockChatUtility.GetUserNameWithStatus(u)).ToArray(),
-                    ctx.User.LegacyName
+                    SockChatUtility.GetUserName(ctx.User)
                 ));
                 return;
             }
 
-            ChannelInfo? channel = ctx.Chat.Channels.Values.FirstOrDefault(c => c.NameEquals(channelName));
+            ChannelInfo? channel = ctx.Chat.Channels.Get(channelName, SockChatUtility.SanitiseChannelName);
 
             if(channel == null) {
                 ctx.Chat.SendTo(ctx.User, new ChannelNotFoundErrorPacket(channelName));
@@ -32,8 +32,8 @@ namespace SharpChat.Commands {
 
             ctx.Chat.SendTo(ctx.User, new WhoChannelResponsePacket(
                 channel.Name,
-                ctx.Chat.GetChannelUsers(channel).Select(user => user.LegacyName).ToArray(),
+                ctx.Chat.GetChannelUsers(channel).Select(user => SockChatUtility.GetUserNameWithStatus(user)).ToArray(),
-                ctx.User.LegacyName
+                SockChatUtility.GetUserNameWithStatus(ctx.User)
             ));
         }
     }

SharpChat/Commands/WhoisCommand.cs

@@ -18,7 +18,8 @@ namespace SharpChat.Commands {
             string ipUserStr = ctx.Args.FirstOrDefault() ?? string.Empty;
             UserInfo? ipUser;
 
-            if(string.IsNullOrWhiteSpace(ipUserStr) || (ipUser = ctx.Chat.Users.Values.FirstOrDefault(u => u.NameEquals(ipUserStr))) == null) {
+            (string name, UsersContext.NameTarget target) = SockChatUtility.ExplodeUserName(ipUserStr);
+            if(string.IsNullOrWhiteSpace(name) || (ipUser = ctx.Chat.Users.Get(name: name, nameTarget: target)) == null) {
                 ctx.Chat.SendTo(ctx.User, new UserNotFoundErrorPacket(ipUserStr));
                 return;
             }

SharpChat/Config/IConfig.cs

@@ -1,8 +1,4 @@
 using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace SharpChat.Config {
     public interface IConfig : IDisposable {

SharpChat/Events/IChatEvent.cs

@@ -1,10 +1,4 @@
-using System;
+namespace SharpChat.Events {
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace SharpChat.Events {
     public interface IChatEvent {
     }
 }

SharpChat/Misuzu/MisuzuAuthInfo.cs

@@ -1,5 +1,4 @@
-using System;
+using System.Text.Json.Serialization;
-using System.Text.Json.Serialization;
 
 namespace SharpChat.Misuzu {
     public class MisuzuAuthInfo {

SharpChat/Packet/AuthSuccessPacket.cs

@@ -1,6 +1,4 @@
-using System;
+namespace SharpChat.Packet {
-
-namespace SharpChat.Packet {
     public class AuthSuccessPacket : ServerPacket {
         private readonly long UserId;
         private readonly string UserName;
@@ -41,7 +39,7 @@ namespace SharpChat.Packet {
                 UserPerms.HasFlag(UserPermissions.CreateChannel) ? (
                     UserPerms.HasFlag(UserPermissions.SetChannelPermanent) ? 2 : 1
                 ) : 0,
-                ChannelName,
+                SockChatUtility.SanitiseChannelName(ChannelName),
                 MaxMessageLength
             );
         }

SharpChat/Packet/ChannelCreatePacket.cs

@@ -1,6 +1,4 @@
-using System;
+namespace SharpChat.Packet {
-
-namespace SharpChat.Packet {
     public class ChannelCreatePacket : ServerPacket {
         private readonly string ChannelName;
         private readonly bool ChannelHasPassword;
@@ -19,7 +17,7 @@ namespace SharpChat.Packet {
         public override string Pack() {
             return string.Format(
                 "4\t0\t{0}\t{1}\t{2}",
-                ChannelName,
+                SockChatUtility.SanitiseChannelName(ChannelName),
                 ChannelHasPassword ? 1 : 0,
                 ChannelIsTemporary ? 1 : 0
             );

SharpChat/Packet/ChannelCreateResponsePacket.cs

@@ -11,7 +11,12 @@ namespace SharpChat.Packet {
         }
 
         public override string Pack() {
-            return string.Format("2\t{0}\t-1\t0\fcrchan\f{1}\t{2}\t10010", Timestamp, ChannelName, SequenceId);
+            return string.Format(
+                "2\t{0}\t-1\t0\fcrchan\f{1}\t{2}\t10010",
+                Timestamp,
+                SockChatUtility.SanitiseChannelName(ChannelName),
+                SequenceId
+            );
         }
     }
 }

SharpChat/Packet/ChannelDeleteNotAllowedErrorPacket.cs

@@ -11,7 +11,12 @@ namespace SharpChat.Packet {
         }
 
         public override string Pack() {
-            return string.Format("2\t{0}\t-1\t1\fndchan\f{1}\t{2}\t10010", Timestamp, ChannelName, SequenceId);
+            return string.Format(
+                "2\t{0}\t-1\t1\fndchan\f{1}\t{2}\t10010",
+                Timestamp,
+                SockChatUtility.SanitiseChannelName(ChannelName),
+                SequenceId
+            );
         }
     }
 }

SharpChat/Packet/ChannelDeletePacket.cs

@@ -1,6 +1,4 @@
-using System;
+namespace SharpChat.Packet {
-
-namespace SharpChat.Packet {
     public class ChannelDeletePacket : ServerPacket {
         private readonly string ChannelName;
 
@@ -9,7 +7,10 @@ namespace SharpChat.Packet {
         }
 
         public override string Pack() {
-            return string.Format("4\t2\t{0}", ChannelName);
+            return string.Format(
+                "4\t2\t{0}",
+                SockChatUtility.SanitiseChannelName(ChannelName)
+            );
         }
     }
 }

SharpChat/Packet/ChannelDeleteResponsePacket.cs

@@ -11,7 +11,12 @@ namespace SharpChat.Packet {
         }
 
         public override string Pack() {
-            return string.Format("2\t{0}\t-1\t0\fdelchan\f{1}\t{2}\t10010", Timestamp, ChannelName, SequenceId);
+            return string.Format(
+                "2\t{0}\t-1\t0\fdelchan\f{1}\t{2}\t10010",
+                Timestamp,
+                SockChatUtility.SanitiseChannelName(ChannelName),
+                SequenceId
+            );
         }
     }
 }

SharpChat/Packet/ChannelNameInUseErrorPacket.cs

@@ -11,7 +11,12 @@ namespace SharpChat.Packet {
         }
 
         public override string Pack() {
-            return string.Format("2\t{0}\t-1\t1\fnischan\f{1}\t{2}\t10010", Timestamp, ChannelName, SequenceId);
+            return string.Format(
+                "2\t{0}\t-1\t1\fnischan\f{1}\t{2}\t10010",
+                Timestamp,
+                SockChatUtility.SanitiseChannelName(ChannelName),
+                SequenceId
+            );
         }
     }
 }

SharpChat/Packet/ChannelNotFoundErrorPacket.cs

@@ -11,7 +11,12 @@ namespace SharpChat.Packet {
         }
 
         public override string Pack() {
-            return string.Format("2\t{0}\t-1\t1\fnochan\f{1}\t{2}\t10010", Timestamp, ChannelName, SequenceId);
+            return string.Format(
+                "2\t{0}\t-1\t1\fnochan\f{1}\t{2}\t10010",
+                Timestamp,
+                SockChatUtility.SanitiseChannelName(ChannelName),
+                SequenceId
+            );
         }
     }
 }

SharpChat/Packet/ChannelPasswordWrongErrorPacket.cs

@@ -11,7 +11,12 @@ namespace SharpChat.Packet {
         }
 
         public override string Pack() {
-            return string.Format("2\t{0}\t-1\t1\fipwchan\f{1}\t{2}\t10010", Timestamp, ChannelName, SequenceId);
+            return string.Format(
+                "2\t{0}\t-1\t1\fipwchan\f{1}\t{2}\t10010",
+                Timestamp,
+                SockChatUtility.SanitiseChannelName(ChannelName),
+                SequenceId
+            );
         }
     }
 }

SharpChat/Packet/ChannelRankTooLowErrorPacket.cs

@@ -11,7 +11,12 @@ namespace SharpChat.Packet {
         }
 
         public override string Pack() {
-            return string.Format("2\t{0}\t-1\t1\fipchan\f{1}\t{2}\t10010", Timestamp, ChannelName, SequenceId);
+            return string.Format(
+                "2\t{0}\t-1\t1\fipchan\f{1}\t{2}\t10010",
+                Timestamp,
+                SockChatUtility.SanitiseChannelName(ChannelName),
+                SequenceId
+            );
         }
     }
 }

SharpChat/Packet/ChannelUpdatePacket.cs

@@ -1,6 +1,4 @@
-using System;
+namespace SharpChat.Packet {
-
-namespace SharpChat.Packet {
     public class ChannelUpdatePacket : ServerPacket {
         private readonly string ChannelNamePrevious;
         private readonly string ChannelNameNew;
@@ -22,8 +20,8 @@ namespace SharpChat.Packet {
         public override string Pack() {
             return string.Format(
                 "4\t1\t{0}\t{1}\t{2}\t{3}",
-                ChannelNamePrevious,
+                SockChatUtility.SanitiseChannelName(ChannelNamePrevious),
-                ChannelNameNew,
+                SockChatUtility.SanitiseChannelName(ChannelNameNew),
                 ChannelHasPassword ? 1 : 0,
                 ChannelIsTemporary ? 1 : 0
             );

SharpChat/Packet/ChannelsPopulatePacket.cs

@@ -1,5 +1,4 @@
-using System;
+using System.Text;
-using System.Text;
 
 namespace SharpChat.Packet {
     public class ChannelsPopulatePacket : ServerPacket {
@@ -19,7 +18,7 @@ namespace SharpChat.Packet {
             foreach(ListEntry entry in Entries)
                 sb.AppendFormat(
                     "\t{0}\t{1}\t{2}",
-                    entry.Name,
+                    SockChatUtility.SanitiseChannelName(entry.Name),
                     entry.HasPassword ? 1 : 0,
                     entry.IsTemporary ? 1 : 0
                 );

SharpChat/Packet/CommandNotAllowedErrorPacket.cs

@@ -11,7 +11,12 @@ namespace SharpChat.Packet {
         }
 
         public override string Pack() {
-            return string.Format("2\t{0}\t-1\t1\fcmdna\f/{1}\t{2}\t10010", Timestamp, CommandName, SequenceId);
+            return string.Format(
+                "2\t{0}\t-1\t1\fcmdna\f/{1}\t{2}\t10010",
+                Timestamp,
+                CommandName,
+                SequenceId
+            );
         }
     }
 }

SharpChat/Packet/MOTDPacket.cs

@@ -13,7 +13,7 @@ namespace SharpChat.Packet {
         public override string Pack() {
             return string.Format(
                 "7\t1\t{0}\t-1\tChatBot\tinherit\t\t0\fsay\f{1}\twelcome\t0\t10010",
-                Timestamp, Utility.Sanitise(Body)
+                Timestamp, SockChatUtility.SanitiseMessageBody(Body)
             );
         }
     }

SharpChat/Packet/MessageAddPacket.cs

@@ -24,7 +24,7 @@ namespace SharpChat.Packet {
         }
 
         public override string Pack() {
-            string body = Utility.Sanitise(Body);
+            string body = SockChatUtility.SanitiseMessageBody(Body);
             if(IsAction)
                 body = string.Format("<i>{0}</i>", body);
 

SharpChat/Packet/MessageBroadcastPacket.cs

@@ -14,7 +14,7 @@ namespace SharpChat.Packet {
             return string.Format(
                 "2\t{0}\t-1\t0\fsay\f{1}\t{2}\t10010",
                 Timestamp,
-                Utility.Sanitise(Body),
+                SockChatUtility.SanitiseMessageBody(Body),
                 SequenceId
             );
         }

SharpChat/Packet/MessagePopulatePacket.cs

@@ -1,5 +1,4 @@
 using SharpChat.EventStorage;
-using System;
 using System.Text;
 
 namespace SharpChat.Packet {
@@ -32,7 +31,7 @@ namespace SharpChat.Packet {
                         sb.AppendFormat(
                             "{0}\t{1}\t{2}\t{3} {4} {5} {6} {7}",
                             Event.Sender?.UserId,
-                            Event.Sender?.LegacyNameWithStatus,
+                            Event.Sender == null ? string.Empty : SockChatUtility.GetUserNameWithStatus(Event.Sender),
                             Event.Sender?.Colour,
                             Event.Sender?.Rank,
                             Event.Sender?.Permissions.HasFlag(UserPermissions.KickUser) == true ? 1 : 0,
@@ -49,7 +48,7 @@ namespace SharpChat.Packet {
                     if(isBroadcast)
                         sb.Append("0\fsay\f");
 
-                    string body = Utility.Sanitise(Event.Data.RootElement.GetProperty("text").GetString());
+                    string body = SockChatUtility.SanitiseMessageBody(Event.Data.RootElement.GetProperty("text").GetString());
                     if(isAction)
                         body = string.Format("<i>{0}</i>", body);
 
@@ -57,11 +56,19 @@ namespace SharpChat.Packet {
                     break;
 
                 case "chan:join":
-                    sb.AppendFormat("{0}\t0\fjchan\f{1}", V1_CHATBOT, Event.Sender?.LegacyName);
+                    sb.AppendFormat(
+                        "{0}\t0\fjchan\f{1}",
+                        V1_CHATBOT,
+                        Event.Sender == null ? string.Empty : SockChatUtility.GetUserName(Event.Sender)
+                    );
                     break;
 
                 case "chan:leave":
-                    sb.AppendFormat("{0}\t0\flchan\f{1}", V1_CHATBOT, Event.Sender?.LegacyName);
+                    sb.AppendFormat(
+                        "{0}\t0\flchan\f{1}",
+                        V1_CHATBOT,
+                        Event.Sender == null ? string.Empty : SockChatUtility.GetUserName(Event.Sender)
+                    );
                     break;
             }
 

SharpChat/Packet/UserChannelForceJoinPacket.cs

@@ -1,6 +1,4 @@
-using System;
+namespace SharpChat.Packet {
-
-namespace SharpChat.Packet {
     public class UserChannelForceJoinPacket : ServerPacket {
         private readonly string ChannelName;
 
@@ -9,7 +7,10 @@ namespace SharpChat.Packet {
         }
 
         public override string Pack() {
-            return string.Format("5\t2\t{0}", ChannelName);
+            return string.Format(
+                "5\t2\t{0}",
+                SockChatUtility.SanitiseChannelName(ChannelName)
+            );
         }
     }
 }

SharpChat/Packet/UserChannelJoinPacket.cs

@@ -1,6 +1,4 @@
-using System;
+namespace SharpChat.Packet {
-
-namespace SharpChat.Packet {
     public class UserChannelJoinPacket : ServerPacket {
         private readonly long UserId;
         private readonly string UserName;

SharpChat/Packet/UserUpdatePacket.cs

@@ -1,6 +1,4 @@
-using System;
+namespace SharpChat.Packet {
-
-namespace SharpChat.Packet {
     public class UserUpdatePacket : ServerPacket {
         private readonly long UserId;
         private readonly string UserName;

SharpChat/Packet/UsersPopulatePacket.cs

@@ -1,5 +1,4 @@
-using System;
+using System.Text;
-using System.Text;
 
 namespace SharpChat.Packet {
     public class UsersPopulatePacket : ServerPacket {

SharpChat/Packet/WhoChannelNotFoundErrorPacket.cs

@@ -11,7 +11,12 @@ namespace SharpChat.Packet {
         }
 
         public override string Pack() {
-            return string.Format("2\t{0}\t-1\t1\fwhoerr\f{1}\t{2}\t10010", Timestamp, ChannelName, SequenceId);
+            return string.Format(
+                "2\t{0}\t-1\t1\fwhoerr\f{1}\t{2}\t10010",
+                Timestamp,
+                SockChatUtility.SanitiseChannelName(ChannelName),
+                SequenceId
+            );
         }
     }
 }

SharpChat/Packet/WhoChannelResponsePacket.cs

@@ -18,7 +18,11 @@ namespace SharpChat.Packet {
         public override string Pack() {
             StringBuilder sb = new();
 
-            sb.AppendFormat("2\t{0}\t-1\t0\fwhochan\f{1}\f", Timestamp, ChannelName);
+            sb.AppendFormat(
+                "2\t{0}\t-1\t0\fwhochan\f{1}\f",
+                Timestamp,
+                SockChatUtility.SanitiseChannelName(ChannelName)
+            );
 
             foreach(string userName in Users) {
                 sb.Append(@"<a href=""javascript:void(0);"" onclick=""UI.InsertChatText(this.innerHTML);""");

SharpChat/PacketHandlerContext.cs

@@ -1,6 +1,4 @@
-using System;
+namespace SharpChat {
-
-namespace SharpChat {
     public class PacketHandlerContext {
         public string Text { get; }
         public ChatContext Chat { get; }

SharpChat/PacketHandlers/AuthHandler.cs

@@ -16,12 +16,12 @@ namespace SharpChat.PacketHandlers {
 
         public AuthHandler(
             MisuzuClient msz,
-            ChannelInfo defaultChannel,
+            ChannelInfo? defaultChannel,
             CachedValue<int> maxMsgLength,
             CachedValue<int> maxConns
         ) {
             Misuzu = msz;
-            DefaultChannel = defaultChannel;
+            DefaultChannel = defaultChannel ?? throw new ArgumentNullException(nameof(defaultChannel));
             MaxMessageLength = maxMsgLength;
             MaxConnections = maxConns;
         }
@@ -114,7 +114,7 @@ namespace SharpChat.PacketHandlers {
 
                 await ctx.Chat.ContextAccess.WaitAsync();
                 try {
-                    UserInfo? user = ctx.Chat.Users.Values.FirstOrDefault(u => u.UserId == fai.UserId);
+                    UserInfo? user = ctx.Chat.Users.Get(fai.UserId);
 
                     if(user == null)
                         user = new UserInfo(

SharpChat/PacketHandlers/PingHandler.cs

@@ -31,7 +31,7 @@ namespace SharpChat.PacketHandlers {
             ctx.Chat.ContextAccess.Wait();
             try {
                 if(LastBump < DateTimeOffset.UtcNow - BumpInterval) {
-                    (string, string)[] bumpList = ctx.Chat.Users.Values
+                    (string, string)[] bumpList = ctx.Chat.Users.All
                         .Where(u => u.Status == UserStatus.Online && ctx.Chat.Connections.Any(c => c.User == u))
                         .Select(u => (u.UserId.ToString(), ctx.Chat.GetRemoteAddresses(u).FirstOrDefault()?.ToString() ?? string.Empty))
                         .ToArray();

SharpChat/PacketHandlers/SendMessageHandler.cs

@@ -1,14 +1,10 @@
-using SharpChat.Commands;
+using SharpChat.Config;
-using SharpChat.Config;
 using SharpChat.Events;
-using SharpChat.EventStorage;
-using SharpChat.Packet;
 using System;
 using System.Collections.Generic;
 using System.Linq;
 
-namespace SharpChat.PacketHandlers
+namespace SharpChat.PacketHandlers {
-{
     public class SendMessageHandler : IPacketHandler {
         private readonly CachedValue<int> MaxMessageLength;
 
@@ -47,8 +43,10 @@ namespace SharpChat.PacketHandlers
 
             ctx.Chat.ContextAccess.Wait();
             try {
-                if(!ctx.Chat.UserLastChannel.TryGetValue(user.UserId, out ChannelInfo? channel)
+                ChannelInfo? channelInfo = ctx.Chat.Channels.Get(
-                    || !ctx.Chat.IsInChannel(user, channel))
+                    ctx.Chat.ChannelsUsers.GetUserLastChannel(user)
+                );
+                if(channelInfo == null)
                     return;
 
                 if(user.Status != UserStatus.Online)
@@ -65,7 +63,7 @@ namespace SharpChat.PacketHandlers
 #endif
 
                 if(messageText.StartsWith("/")) {
-                    UserCommandContext context = new(messageText, ctx.Chat, user, ctx.Connection, channel);
+                    UserCommandContext context = new(messageText, ctx.Chat, user, ctx.Connection, channelInfo);
 
                     IUserCommand? command = null;
 
@@ -83,7 +81,7 @@ namespace SharpChat.PacketHandlers
 
                 ctx.Chat.DispatchEvent(new MessageCreateEvent(
                     SharpId.Next(),
-                    channel,
+                    channelInfo,
                     user,
                     DateTimeOffset.Now,
                     messageText,

SharpChat/SockChatServer.cs

@@ -36,8 +36,6 @@ namespace SharpChat {
 
         private bool IsShuttingDown = false;
 
-        private ChannelInfo DefaultChannel { get; set; }
-
         public SockChatServer(HttpClient httpClient, MisuzuClient msz, IEventStorage evtStore, IConfig config) {
             Logger.Write("Initialising Sock Chat server...");
 
@@ -67,15 +65,13 @@ namespace SharpChat {
                         rank: channelCfg.SafeReadValue("minRank", 0)
                     );
 
-                    Context.Channels.Add(channelInfo.Name, channelInfo);
+                    Context.Channels.Add(channelInfo);
-                    DefaultChannel ??= channelInfo;
                 }
 
-            DefaultChannel ??= new ChannelInfo("Default");
+            if(Context.Channels.PublicCount < 1)
-            if(Context.Channels.Count < 1)
+                Context.Channels.Add(new ChannelInfo("Default"));
-                Context.Channels.Add(DefaultChannel.Name, DefaultChannel);
 
-            GuestHandlers.Add(new AuthHandler(Misuzu, DefaultChannel, MaxMessageLength, MaxConnections));
+            GuestHandlers.Add(new AuthHandler(Misuzu, Context.Channels.MainChannel, MaxMessageLength, MaxConnections));
 
             AuthedHandlers.AddRange(new IPacketHandler[] {
                 new PingHandler(Misuzu),

SharpChat/SockChatUtility.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Text.RegularExpressions;
+
+namespace SharpChat {
+    public static class SockChatUtility {
+        private static readonly Regex ChannelName = new(@"[^A-Za-z0-9\-_]", RegexOptions.CultureInvariant | RegexOptions.Compiled);
+
+        public static string SanitiseMessageBody(string? body) {
+            if(string.IsNullOrEmpty(body))
+                return string.Empty;
+
+            return body.Replace("<", "&lt;").Replace(">", "&gt;").Replace("\n", " <br/> ").Replace("\t", "    ");
+        }
+
+        public static string SanitiseChannelName(string name) {
+            return ChannelName.Replace(name.Replace(" ", "_"), "-");
+        }
+
+        public static bool CheckChannelName(string name) {
+            return name.Length < 1 || ChannelName.IsMatch(name);
+        }
+
+        public static string GetUserName(UserInfo info) {
+            return string.IsNullOrWhiteSpace(info.NickName) ? info.UserName : $"~{info.NickName}";
+        }
+
+        public static string GetUserNameWithStatus(UserInfo info) {
+            string name = GetUserName(info);
+
+            if(info.Status == UserStatus.Away)
+                name = string.Format(
+                    "&lt;{0}&gt;_{1}",
+                    info.StatusText[..Math.Min(info.StatusText.Length, 5)].ToUpperInvariant(),
+                    name
+                );
+
+            return name;
+        }
+
+        public static (string, UsersContext.NameTarget) ExplodeUserName(string name) {
+            UsersContext.NameTarget target = UsersContext.NameTarget.UserName;
+
+            if(name.StartsWith("<")) {
+                int gt = name.IndexOf(">_");
+                if(gt > 0) {
+                    gt += 2;
+                    name = name[gt..];
+                }
+            } else if(name.StartsWith("&lt;")) {
+                int gt = name.IndexOf("&gt;_");
+                if(gt > 0) {
+                    gt += 5;
+                    name = name[gt..];
+                }
+            }
+
+            if(name.StartsWith("~")) {
+                target = UsersContext.NameTarget.NickName;
+                name = name[1..];
+            }
+
+            return (name, target);
+        }
+    }
+}

SharpChat/UserInfo.cs

@@ -1,7 +1,4 @@
-using System;
+namespace SharpChat {
-using System.Text;
-
-namespace SharpChat {
     public class UserInfo {
         public const int DEFAULT_SIZE = 30;
         public const int DEFAULT_MINIMUM_DELAY = 10000;
@@ -17,21 +14,6 @@ namespace SharpChat {
         public UserStatus Status { get; set; }
         public string StatusText { get; set; }
 
-        public string LegacyName => string.IsNullOrWhiteSpace(NickName) ? UserName : $"~{NickName}";
-
-        public string LegacyNameWithStatus {
-            get {
-                StringBuilder sb = new();
-
-                if(Status == UserStatus.Away)
-                    sb.AppendFormat("<{0}>_", StatusText[..Math.Min(StatusText.Length, 5)].ToUpperInvariant());
-
-                sb.Append(LegacyName);
-
-                return sb.ToString();
-            }
-        }
-
         public UserInfo(
             long userId,
             string userName,
@@ -54,13 +36,6 @@ namespace SharpChat {
             IsSuper = isSuper;
         }
 
-        public bool NameEquals(string? name) {
-            return string.Equals(name, UserName, StringComparison.InvariantCultureIgnoreCase)
-                || string.Equals(name, NickName, StringComparison.InvariantCultureIgnoreCase)
-                || string.Equals(name, LegacyName, StringComparison.InvariantCultureIgnoreCase)
-                || string.Equals(name, LegacyNameWithStatus, StringComparison.InvariantCultureIgnoreCase);
-        }
-
         public static string GetDMChannelName(UserInfo user1, UserInfo user2) {
             return user1.UserId < user2.UserId
                 ? $"@{user1.UserId}-{user2.UserId}"

SharpChat/UsersContext.cs

@@ -0,0 +1,112 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace SharpChat {
+    public class UsersContext {
+        [Flags]
+        public enum NameTarget {
+            None = 0,
+            UserName = 1,
+            NickName = 2,
+            UserAndNickName = UserName | NickName,
+        }
+
+        private readonly List<UserInfo> Users = new();
+
+        public int TotalCount { get; private set; }
+
+        public UserInfo[] All => Users.ToArray();
+
+        public UserInfo? Get(
+            long? userId = null,
+            string? name = null,
+            NameTarget nameTarget = NameTarget.UserName
+        ) {
+            foreach(UserInfo info in Users) {
+                if(userId != null && info.UserId != userId)
+                    continue;
+                if(name != null) {
+                    // this could probably all fit in a single if condition, but it'd be massive and disgusting
+                    // and require more thinking power than my goldfish brain can muster
+                    bool match = false;
+                    if(nameTarget.HasFlag(NameTarget.UserName) && info.UserName.Equals(name, StringComparison.InvariantCultureIgnoreCase))
+                        match = true;
+                    else if(nameTarget.HasFlag(NameTarget.NickName) && info.NickName.Equals(name, StringComparison.InvariantCultureIgnoreCase))
+                        match = true;
+                    if(!match)
+                        continue;
+                }
+
+                return info;
+            }
+
+            return null;
+        }
+
+        public UserInfo[] GetMany(
+            long[]? userIds = null,
+            string[]? names = null,
+            NameTarget namesTarget = NameTarget.UserName,
+            int? minRank = null
+        ) {
+            List<UserInfo> users = new();
+
+            foreach(UserInfo info in Users) {
+                if(minRank != null && info.Rank < minRank)
+                    continue;
+
+                if(userIds != null && !userIds.Contains(info.UserId))
+                    continue;
+
+                if(names?.Length > 0) {
+                    bool match = false;
+                    foreach(string name in names) {
+                        if(namesTarget.HasFlag(NameTarget.UserName) && info.UserName.Equals(name, StringComparison.InvariantCultureIgnoreCase))
+                            match = true;
+                        else if(namesTarget.HasFlag(NameTarget.NickName) && info.NickName.Equals(name, StringComparison.InvariantCultureIgnoreCase))
+                            match = true;
+                    }
+
+                    if(!match)
+                        continue;
+                }
+
+                users.Add(info);
+            }
+
+            return users.ToArray();
+        }
+
+        public void Add(UserInfo info) {
+            if(Get(info.UserId, info.UserName) != null)
+                throw new ArgumentException("A user with that id and/or name has already been registred.", nameof(info));
+
+            Users.Add(info);
+            ++TotalCount;
+        }
+
+        public void Remove(UserInfo info) {
+            if(!Users.Contains(info)) {
+                Remove(info.UserId);
+                return;
+            }
+
+            Users.Remove(info);
+            --TotalCount;
+        }
+
+        public void Remove(
+            long? userId = null,
+            string? name = null,
+            NameTarget nameTarget = NameTarget.UserName
+        ) {
+            UserInfo? info = Get(userId, name, nameTarget);
+            if(info == null)
+                return;
+
+            Users.Remove(info);
+            --TotalCount;
+        }
+    }
+}

SharpChat/Utility.cs

@@ -1,10 +0,0 @@
-namespace SharpChat {
-    public static class Utility {
-        public static string Sanitise(string? body) {
-            if(string.IsNullOrEmpty(body))
-                return string.Empty;
-
-            return body.Replace("<", "&lt;").Replace(">", "&gt;").Replace("\n", " <br/> ").Replace("\t", "    ");
-        }
-    }
-}