feat: enhance IRC support with display name handling, private channel tracking, and connection identification

src/EchoHub.Client/UI/Chat/ChatMessageManager.cs

@@ -381,6 +381,9 @@ public sealed class ChatMessageManager
     private List<ChatLine> FormatMessage(MessageDto message)
     {
         var time = FormatTime(message.SentAt);
+        // Show the display name, but keep color + click identity keyed to the username
+        // so they stay consistent with the user list and profile lookups.
+        var senderName = message.SenderDisplayName ?? message.SenderUsername;
         var senderColor = HexColorHelper.ParseHexColor(message.SenderNicknameColor)
             ?? NickColorHelper.GetAttribute(message.SenderUsername);
 
@@ -394,7 +397,7 @@ public sealed class ChatMessageManager
             var displayContent = EmojiHelper.ReplaceEmoji(message.Content);
             var contentLines = displayContent.Split('\n');
 
-            var header = HeaderSegments(time, message.SenderUsername, senderColor);
+            var header = HeaderSegments(time, senderName, senderColor);
             header.AddRange(ChatColors.SplitMentions(contentLines[0].TrimEnd('\r')));
             lines.Add(new ChatLine(header));
 
@@ -413,7 +416,7 @@ public sealed class ChatMessageManager
                 1 => $"[{attachments[0].Kind.ToString().ToLowerInvariant()}]",
                 _ => $"[{attachments.Count} attachments]",
             };
-            var header = HeaderSegments(time, message.SenderUsername, senderColor);
+            var header = HeaderSegments(time, senderName, senderColor);
             header.Add(new(summary, null));
             lines.Add(new ChatLine(header));
         }

src/EchoHub.Client/UI/ListSources/ChannelListSource.cs

@@ -18,6 +18,7 @@ public class ChannelListSource : IListDataSource
     private readonly Dictionary<string, int> _unreadCounts = [];
     private readonly HashSet<string> _protectedChannels = [];
     private readonly HashSet<string> _mentionChannels = [];
+    private readonly HashSet<string> _privateChannels = [];
     private string _activeChannel = string.Empty;
 
     public event NotifyCollectionChangedEventHandler? CollectionChanged;
@@ -32,7 +33,8 @@ public class ChannelListSource : IListDataSource
     private static readonly Attribute MentionAttr = new(new Color(230, 140, 60), Color.None);
 
     public void Update(List<string> channels, Dictionary<string, int> unread, string activeChannel,
-        IReadOnlySet<string>? protectedChannels = null, IReadOnlySet<string>? mentionChannels = null)
+        IReadOnlySet<string>? protectedChannels = null, IReadOnlySet<string>? mentionChannels = null,
+        IReadOnlySet<string>? privateChannels = null)
     {
         _channelNames.Clear();
         _channelNames.AddRange(channels);
@@ -45,6 +47,9 @@ public class ChannelListSource : IListDataSource
         _mentionChannels.Clear();
         if (mentionChannels is not null)
             _mentionChannels.UnionWith(mentionChannels);
+        _privateChannels.Clear();
+        if (privateChannels is not null)
+            _privateChannels.UnionWith(privateChannels);
         _activeChannel = activeChannel;
         MaxItemLength = channels.Count > 0 ? channels.Max(c => c.Length + 6) : 0;
         if (!SuspendCollectionChangedEvent)
@@ -67,8 +72,12 @@ public class ChannelListSource : IListDataSource
         var normalAttr = listView.GetAttributeForRole(VisualRole.Normal);
         var focusAttr = listView.GetAttributeForRole(VisualRole.Focus);
         var prefix = isActive ? "> " : "  ";
-        // Trailing * marks password-protected (+k) channels
-        var channelText = _protectedChannels.Contains(name) ? $"#{name}*" : $"#{name}";
+        // Trailing * marks password-protected (+k) channels; ~ marks private (unlisted) ones
+        var channelText = $"#{name}";
+        if (_protectedChannels.Contains(name))
+            channelText += "*";
+        if (_privateChannels.Contains(name))
+            channelText += "~";
         var badge = hasUnread ? $" ({unread})" : "";
 
         // Resolve Transparent backgrounds to the view's actual background

src/EchoHub.Client/UI/MainWindow.cs

@@ -1317,8 +1317,11 @@ public sealed partial class MainWindow : Runnable
     /// </summary>
     private void RefreshChannelList()
     {
+        var privateChannels = _channelNames
+            .Where(n => _channelPublic.TryGetValue(n, out var isPublic) && !isPublic)
+            .ToHashSet();
         _channelListSource.Update(_channelNames, _messageManager.GetUnreadCounts(), _messageManager.CurrentChannel,
-            _channelProtected, _messageManager.MentionChannels);
+            _channelProtected, _messageManager.MentionChannels, privateChannels);
         _channelList.Source = _channelListSource;
 
         // Restore selection to current channel
@@ -1394,6 +1397,10 @@ public sealed partial class MainWindow : Runnable
             var text = roleTag.Length > 0
                 ? $"{statusIcon} {roleTag} {name}"
                 : $"{statusIcon} {name}";
+            // Users connected only via the IRC gateway get a tag — they lack client features
+            // (encryption, attachments, profiles), which is useful context in conversation.
+            if (u.IsIrc)
+                text += " [irc]";
             // Fall back to the deterministic per-nick palette so user-list colors
             // match the same user's messages in chat.
             var nameColor = HexColorHelper.ParseHexColor(u.NicknameColor)

src/EchoHub.Core/Constants/HubConstants.cs

@@ -4,6 +4,12 @@ public static class HubConstants
 {
     public const string ChatHubPath = "/hubs/chat";
     public const string DefaultChannel = "general";
+
+    /// <summary>
+    /// Connection-id prefix for IRC gateway connections. The presence tracker uses it to
+    /// tell IRC-only users apart from native (SignalR) clients.
+    /// </summary>
+    public const string IrcConnectionIdPrefix = "irc-";
     public const int DefaultHistoryCount = 100;
     public const int MaxMessageLength = 2000;
     public const int MaxImageSizeBytes = 10 * 1024 * 1024; // 10 MB

src/EchoHub.Core/DTOs/ChatDtos.cs

@@ -10,7 +10,8 @@ public record MessageDto(
     string ChannelName,
     DateTimeOffset SentAt,
     List<AttachmentDto>? Attachments = null,
-    List<EmbedDto>? Embeds = null);
+    List<EmbedDto>? Embeds = null,
+    string? SenderDisplayName = null);
 
 /// <summary>
 /// A file attached to a message. <see cref="AsciiPreview"/> holds the color-tag art for

src/EchoHub.Core/DTOs/ProfileDtos.cs

@@ -30,6 +30,7 @@ public record UserPresenceDto(
     string? NicknameColor,
     UserStatus Status,
     string? StatusMessage,
-    ServerRole Role);
+    ServerRole Role,
+    bool IsIrc = false);
 
 public record AvatarUploadResponse(string AvatarAscii);

src/EchoHub.Server.Irc/IrcClientConnection.cs

@@ -1,5 +1,6 @@
 using System.Net.Sockets;
 using System.Text;
+using EchoHub.Core.Constants;
 
 namespace EchoHub.Server.Irc;
 
@@ -14,7 +15,7 @@ public sealed class IrcClientConnection : IAsyncDisposable
     private readonly SemaphoreSlim _writeLock = new(1, 1);
 
     // Connection identity
-    public string ConnectionId { get; } = $"irc-{Guid.NewGuid()}";
+    public string ConnectionId { get; } = $"{HubConstants.IrcConnectionIdPrefix}{Guid.NewGuid()}";
 
     // Registration state
     public string? Nickname { get; set; }

src/EchoHub.Server/Controllers/ChannelsController.cs

@@ -308,7 +308,8 @@ public class ChannelsController : ControllerBase
             sender?.NicknameColor,
             channelName,
             message.SentAt,
-            attachmentDtos);
+            attachmentDtos,
+            SenderDisplayName: sender?.DisplayName);
 
         await _chatService.BroadcastMessageAsync(channelName, messageDto);
 
@@ -444,7 +445,8 @@ public class ChannelsController : ControllerBase
             sender?.NicknameColor,
             channelName,
             message.SentAt,
-            [new AttachmentDto(AttachmentKind.Image, attachmentUrl, fileName, imageBytes.Length, _encryption.Encrypt(preview))]);
+            [new AttachmentDto(AttachmentKind.Image, attachmentUrl, fileName, imageBytes.Length, _encryption.Encrypt(preview))],
+            SenderDisplayName: sender?.DisplayName);
 
         await _chatService.BroadcastMessageAsync(channelName, messageDto);
 

src/EchoHub.Server/Services/ChatService.cs

@@ -121,7 +121,8 @@ public class ChatService : IChatService
                 {
                     presence = new UserPresenceDto(
                         user.Username, user.DisplayName, user.NicknameColor,
-                        user.Status, user.StatusMessage, user.Role);
+                        user.Status, user.StatusMessage, user.Role,
+                        _presenceTracker.IsIrcOnly(user.Username));
                 }
             }
             catch (Exception ex)
@@ -236,7 +237,8 @@ public class ChatService : IChatService
             sender?.NicknameColor,
             channelName,
             message.SentAt,
-            Embeds: embeds);
+            Embeds: embeds,
+            SenderDisplayName: sender?.DisplayName);
 
         await BroadcastToAllAsync(b => b.SendMessageToChannelAsync(channelName, messageDto));
 
@@ -279,7 +281,8 @@ public class ChatService : IChatService
             user.NicknameColor,
             status,
             statusMessage,
-            user.Role);
+            user.Role,
+            _presenceTracker.IsIrcOnly(user.Username));
 
         var channels = _presenceTracker.GetChannelsForUser(username);
         await BroadcastToAllAsync(b => b.SendUserStatusChangedAsync(channels, presence));
@@ -295,16 +298,20 @@ public class ChatService : IChatService
         using var scope = _scopeFactory.CreateScope();
         var db = scope.ServiceProvider.GetRequiredService<EchoHubDbContext>();
 
-        return await db.Users
+        var users = await db.Users
             .Where(u => onlineUsernames.Contains(u.Username) && u.Status != UserStatus.Invisible)
-            .Select(u => new UserPresenceDto(
+            .ToListAsync();
+
+        // IsIrcOnly comes from the in-memory tracker, so map outside the EF query
+        return users.Select(u => new UserPresenceDto(
                 u.Username,
                 u.DisplayName,
                 u.NicknameColor,
                 u.Status,
                 u.StatusMessage,
-                u.Role))
-            .ToListAsync();
+                u.Role,
+                _presenceTracker.IsIrcOnly(u.Username)))
+            .ToList();
     }
 
     public Task BroadcastMessageAsync(string channelName, MessageDto message)
@@ -380,7 +387,7 @@ public class ChatService : IChatService
             .Join(db.Users,
                 m => m.SenderUserId,
                 u => u.Id,
-                (m, u) => new { m, u.NicknameColor })
+                (m, u) => new { m, u.NicknameColor, u.DisplayName })
             .ToListAsync();
 
         raw.Reverse();
@@ -448,7 +455,8 @@ public class ChatService : IChatService
                 channelName,
                 x.m.SentAt,
                 attachments,
-                embeds));
+                embeds,
+                x.DisplayName));
         }
 
         // Lazily delete the pruned messages (+ their attachment rows) as they're encountered.

src/EchoHub.Server/Services/PresenceTracker.cs

@@ -1,4 +1,5 @@
 using System.Collections.Concurrent;
+using EchoHub.Core.Constants;
 
 namespace EchoHub.Server.Services;
 
@@ -174,6 +175,20 @@ public class PresenceTracker
         return _userConnections.TryGetValue(username, out var connections) && connections.Count > 0;
     }
 
+    /// <summary>
+    /// True when the user is online exclusively through the IRC gateway. A user who also has a
+    /// native client connected has full features, so they don't count as IRC-only.
+    /// </summary>
+    public bool IsIrcOnly(string username)
+    {
+        lock (_lock)
+        {
+            return _userConnections.TryGetValue(username, out var connections)
+                && connections.Count > 0
+                && connections.All(c => c.StartsWith(HubConstants.IrcConnectionIdPrefix, StringComparison.Ordinal));
+        }
+    }
+
     public int GetOnlineUserCount()
     {
         return _userConnections.Count;

src/EchoHub.Tests/PresenceTrackerTests.cs

@@ -1,3 +1,4 @@
+using EchoHub.Core.Constants;
 using EchoHub.Server.Services;
 using Xunit;
 
@@ -65,4 +66,48 @@ public class PresenceTrackerTests
         Assert.Contains("general", channels);
         Assert.Contains("random", channels);
     }
+
+    [Fact]
+    public void IsIrcOnly_AllConnectionsIrc_ReturnsTrue()
+    {
+        var tracker = new PresenceTracker();
+        tracker.UserConnected($"{HubConstants.IrcConnectionIdPrefix}conn1", Guid.NewGuid(), "alice");
+        Assert.True(tracker.IsIrcOnly("alice"));
+    }
+
+    [Fact]
+    public void IsIrcOnly_NativeConnection_ReturnsFalse()
+    {
+        var tracker = new PresenceTracker();
+        tracker.UserConnected("conn1", Guid.NewGuid(), "alice");
+        Assert.False(tracker.IsIrcOnly("alice"));
+    }
+
+    [Fact]
+    public void IsIrcOnly_MixedConnections_ReturnsFalse()
+    {
+        var tracker = new PresenceTracker();
+        var userId = Guid.NewGuid();
+        tracker.UserConnected($"{HubConstants.IrcConnectionIdPrefix}conn1", userId, "alice");
+        tracker.UserConnected("conn2", userId, "alice");
+        Assert.False(tracker.IsIrcOnly("alice"));
+    }
+
+    [Fact]
+    public void IsIrcOnly_OfflineUser_ReturnsFalse()
+    {
+        var tracker = new PresenceTracker();
+        Assert.False(tracker.IsIrcOnly("nobody"));
+    }
+
+    [Fact]
+    public void IsIrcOnly_NativeConnectionDisconnects_BecomesTrue()
+    {
+        var tracker = new PresenceTracker();
+        var userId = Guid.NewGuid();
+        tracker.UserConnected($"{HubConstants.IrcConnectionIdPrefix}conn1", userId, "alice");
+        tracker.UserConnected("conn2", userId, "alice");
+        tracker.UserDisconnected("conn2");
+        Assert.True(tracker.IsIrcOnly("alice"));
+    }
 }