Add message reply support and new commands

src/Decho/Models/MessageModel.cs

@@ -2,7 +2,15 @@ using EchoHub.Core.DTOs;
 
 namespace Decho.Models;
 
-public sealed class MessageModel(string id, UserModel author, DateTimeOffset sentAt, string content, string channelName, string? serverUrl = null, List<AttachmentDto>? attachments = null)
+public sealed class MessageModel(
+    string id,
+    UserModel author,
+    DateTimeOffset sentAt,
+    string content,
+    string channelName,
+    string? serverUrl = null,
+    List<AttachmentDto>? attachments = null,
+    ReplyRefDto? replyTo = null)
 {
     public string Id { get; } = id;
 
@@ -17,4 +25,6 @@ public sealed class MessageModel(string id, UserModel author, DateTimeOffset sen
     public string? ServerUrl { get; } = serverUrl;
 
     public List<AttachmentDto> Attachments { get; } = attachments ?? [];
+
+    public ReplyRefDto? ReplyTo { get; } = replyTo;
 }

src/Decho/Services/ConnectionService.cs

@@ -52,6 +52,8 @@ public sealed class ConnectionService : IDisposable
 
     public event Action<string, string>? ErrorOccurred;
 
+    public event Action<string, string>? ChannelDeleted;
+
     private readonly Dictionary<string, ServerConnection> _connections = new(StringComparer.OrdinalIgnoreCase);
     internal IReadOnlyDictionary<string, ServerConnection> Connections => _connections;
 
@@ -85,14 +87,14 @@ public sealed class ConnectionService : IDisposable
         ServerRemoved?.Invoke(serverUrl);
     }
 
-    public async Task SendMessageAsync(string serverUrl, string channelName, string content)
+    public async Task SendMessageAsync(string serverUrl, string channelName, string content, Guid? replyToMessageId = null)
     {
         if (!_connections.TryGetValue(serverUrl, out ServerConnection? entry))
         {
             throw new InvalidOperationException("Not connected to server");
         }
 
-        await entry.Manager.SendMessageAsync(channelName, content);
+        await entry.Manager.SendMessageAsync(channelName, content, replyToMessageId);
     }
 
     public async Task SendMessageWithAttachmentsAsync(string serverUrl, string channelName, string content, IReadOnlyList<string> filePaths, string? size = null)
@@ -340,6 +342,58 @@ public sealed class ConnectionService : IDisposable
         return await entry.ApiClient.GetChannelCryptoAsync(channelName);
     }
 
+    // ── Invites / Account ────────────────────────────────────────────────
+
+    public async Task<InviteDto?> CreateInviteAsync(string serverUrl, int? maxUses, int? expiresInHours)
+    {
+        if (!_connections.TryGetValue(serverUrl, out ServerConnection? entry))
+        {
+            return null;
+        }
+
+        return await entry.ApiClient.CreateInviteAsync(maxUses, expiresInHours);
+    }
+
+    public async Task<List<InviteDto>> GetInvitesAsync(string serverUrl)
+    {
+        if (!_connections.TryGetValue(serverUrl, out ServerConnection? entry))
+        {
+            return [];
+        }
+
+        return await entry.ApiClient.GetInvitesAsync();
+    }
+
+    public async Task RevokeInviteAsync(string serverUrl, string code)
+    {
+        if (!_connections.TryGetValue(serverUrl, out ServerConnection? entry))
+        {
+            return;
+        }
+
+        await entry.ApiClient.RevokeInviteAsync(code);
+    }
+
+    public async Task<string> ExportMyDataAsync(string serverUrl)
+    {
+        if (!_connections.TryGetValue(serverUrl, out ServerConnection? entry))
+        {
+            throw new InvalidOperationException("Not connected");
+        }
+
+        return await entry.ApiClient.ExportMyDataAsync();
+    }
+
+    public async Task DeleteMyAccountAsync(string serverUrl, string password)
+    {
+        if (!_connections.TryGetValue(serverUrl, out ServerConnection? entry))
+        {
+            throw new InvalidOperationException("Not connected");
+        }
+
+        await entry.ApiClient.DeleteMyAccountAsync(password);
+    }
+
     public void MarkChannelEncrypted(string serverUrl, string channelName, bool isEncrypted)
     {
         if (!_connections.TryGetValue(serverUrl, out ServerConnection? entry))
@@ -664,7 +718,7 @@ public sealed class ConnectionService : IDisposable
     {
         UserModel author = new UserModel(
             dto.SenderUsername,
-            dto.SenderUsername,
+            dto.SenderDisplayName ?? dto.SenderUsername,
             dto.SenderNicknameColor);
 
         List<AttachmentDto> attachments = dto.Attachments ?? [];
@@ -676,7 +730,8 @@ public sealed class ConnectionService : IDisposable
             dto.Content,
             dto.ChannelName,
             entry.Server.ServerUrl,
-            attachments);
+            attachments,
+            dto.ReplyTo);
     }
 
     internal ServerConnection? GetConnection(string serverUrl)
@@ -875,6 +930,11 @@ public sealed class ConnectionService : IDisposable
             entry.User.StatusMessage = presence.StatusMessage;
         };
 
+        conn.ChannelDeleted += channelName =>
+        {
+            ChannelDeleted?.Invoke(entry.Server.ServerUrl, channelName);
+        };
+
         conn.ChannelUpdated += channel =>
         {
             ChannelModel? existing = entry.Server.Channels.FirstOrDefault(c =>

src/Decho/ViewModels/MainWindowViewModel.cs

@@ -11,11 +11,13 @@ using EchoHub.Core.Constants;
 using EchoHub.Core.DTOs;
 using EchoHub.Core.Models;
 using EchoHub.Core.Security;
+using EchoHub.Core.Services;
 
 using MsBox.Avalonia;
 using MsBox.Avalonia.Base;
 using MsBox.Avalonia.Enums;
 
+using System.Diagnostics;
 using System.Reactive;
 using System.Reactive.Linq;
 
@@ -33,12 +35,6 @@ public sealed class MainWindowViewModel : ViewModelBase
 
     public ChatViewModel Chat { get; }
 
-    public string StatusText
-    {
-        get;
-        set => this.RaiseAndSetIfChanged(ref field, value);
-    } = "Ready";
-
     public ConnectionService ConnectionService { get; }
 
     public ReactiveCommand<Unit, Unit> AddServerCommand { get; }
@@ -101,8 +97,6 @@ public sealed class MainWindowViewModel : ViewModelBase
 
     private async Task ConnectAndSaveAsync(ConnectDialogResult result)
     {
-        StatusText = "Connecting...";
-
         if (result.IsSavedSession && result.SavedRefreshToken is not null)
         {
             await ConnectionService.ConnectWithSavedTokenAsync(
@@ -195,6 +189,20 @@ public sealed class MainWindowViewModel : ViewModelBase
         return result;
     }
 
+    private void ShowSystemMessage(string text)
+    {
+        Avalonia.Threading.Dispatcher.UIThread.Post(() =>
+        {
+            Chat.Messages.Add(new MessageViewModel(new MessageModel(
+                Guid.NewGuid().ToString("N"),
+                new UserModel("system", "System"),
+                DateTimeOffset.Now,
+                text,
+                Chat.CurrentChannelName,
+                Chat.CurrentServerUrl)));
+        });
+    }
+
     private void WireCommandHandlerEvents()
     {
         _commandHandler.OnSetStatus += async (status, message) =>
@@ -205,7 +213,7 @@ public sealed class MainWindowViewModel : ViewModelBase
                 return;
             }
 
-            await ConnectionService.UpdateStatusAsync(serverUrl, status, message);
+            await ConnectionService.UpdateStatusAsync(serverUrl, status ?? UserStatus.Online, message);
         };
 
         _commandHandler.OnSetTheme += themeName =>
@@ -313,7 +321,7 @@ public sealed class MainWindowViewModel : ViewModelBase
 
             List<UserPresenceDto> users = await ConnectionService.GetOnlineUsersAsync(serverUrl, channel);
             string userList = string.Join(", ", users.Select(u => u.DisplayName ?? u.Username));
-            StatusText = $"Online in #{channel}: {userList}";
+            ShowSystemMessage($"Online in #{channel}: {userList}");
         };
 
         _commandHandler.OnSetTopic += async topic =>
@@ -428,6 +436,114 @@ public sealed class MainWindowViewModel : ViewModelBase
 
         _commandHandler.OnHelp += () => Task.CompletedTask;
 
+        _commandHandler.OnSendAction += async text =>
+        {
+            await HandleSendTextAsync(MessageConventions.FormatAction(text));
+        };
+
+        _commandHandler.OnSendBanner += async text =>
+        {
+            string? banner = AsciiBannerService.Render(text);
+            if (banner is null) return;
+            await HandleSendTextAsync(banner);
+        };
+
+        _commandHandler.OnCreateInvite += async (maxUses, expiresInHours) =>
+        {
+            string serverUrl = GetCurrentServerUrl();
+            if (string.IsNullOrEmpty(serverUrl)) return;
+
+            try
+            {
+                InviteDto? invite = await ConnectionService.CreateInviteAsync(serverUrl, maxUses, expiresInHours);
+                if (invite is not null)
+                    ShowSystemMessage($"Invite code: {invite.Code}");
+            }
+            catch (Exception ex)
+            {
+                ShowSystemMessage($"Failed to create invite: {ex.Message}");
+            }
+        };
+
+        _commandHandler.OnListInvites += async () =>
+        {
+            string serverUrl = GetCurrentServerUrl();
+            if (string.IsNullOrEmpty(serverUrl)) return;
+
+            try
+            {
+                List<InviteDto> invites = await ConnectionService.GetInvitesAsync(serverUrl);
+                if (invites.Count == 0)
+                    ShowSystemMessage("No invite codes.");
+                else
+                    ShowSystemMessage(string.Join(" | ", invites.Select(i => $"{i.Code} ({i.UseCount}/{i.MaxUses})")));
+            }
+            catch (Exception ex)
+            {
+                ShowSystemMessage($"Failed to list invites: {ex.Message}");
+            }
+        };
+
+        _commandHandler.OnRevokeInvite += async code =>
+        {
+            string serverUrl = GetCurrentServerUrl();
+            if (string.IsNullOrEmpty(serverUrl)) return;
+
+            try
+            {
+                await ConnectionService.RevokeInviteAsync(serverUrl, code);
+                ShowSystemMessage($"Invite {code} revoked.");
+            }
+            catch (Exception ex)
+            {
+                ShowSystemMessage($"Failed to revoke invite: {ex.Message}");
+            }
+        };
+
+        _commandHandler.OnExportData += async () =>
+        {
+            string serverUrl = GetCurrentServerUrl();
+            if (string.IsNullOrEmpty(serverUrl)) return;
+
+            try
+            {
+                string data = await ConnectionService.ExportMyDataAsync(serverUrl);
+                string fileName = $"echohub-export-{DateTimeOffset.Now:yyyyMMdd-HHmmss}.json";
+                string downloadsPath = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
+                string filePath = Path.Combine(downloadsPath, "Downloads", fileName);
+                await File.WriteAllTextAsync(filePath, data);
+                ShowSystemMessage($"Data exported to {filePath}");
+            }
+            catch (Exception ex)
+            {
+                Debug.WriteLine($"Export failed: {ex.Message}");
+            }
+        };
+
+        _commandHandler.OnDeleteAccount += async () =>
+        {
+            string serverUrl = GetCurrentServerUrl();
+            if (string.IsNullOrEmpty(serverUrl)) return;
+
+            IMsBox<ButtonResult> confirmBox = MessageBoxManager.GetMessageBoxStandard(
+                "Delete Account", "Are you sure you want to permanently delete your account? This cannot be undone.", ButtonEnum.YesNo);
+            ButtonResult confirm = await confirmBox.ShowWindowDialogAsync(_mainWindow);
+            if (confirm != ButtonResult.Yes) return;
+
+            string? pwd = await ShowPromptWindowAsync("Confirm Password", "Enter your password to confirm account deletion:", "Delete");
+            if (string.IsNullOrEmpty(pwd)) return;
+
+            try
+            {
+                await ConnectionService.DeleteMyAccountAsync(serverUrl, pwd);
+                ShowSystemMessage("Account deleted.");
+            }
+            catch (Exception ex)
+            {
+                Debug.WriteLine($"Delete failed: {ex.Message}");
+            }
+        };
+
         _commandHandler.OnSendFile += async (target, size) =>
         {
             string serverUrl = GetCurrentServerUrl();
@@ -451,7 +567,7 @@ public sealed class MainWindowViewModel : ViewModelBase
             }
             catch (Exception ex)
             {
-                StatusText = $"Send failed: {ex.Message}";
+                ShowSystemMessage($"Send failed: {ex.Message}");
             }
         };
 
@@ -509,7 +625,7 @@ public sealed class MainWindowViewModel : ViewModelBase
                 {
                     if (profile is null)
                     {
-                        StatusText = "User not found";
+                        Debug.WriteLine("User not found");
                         return;
                     }
 
@@ -522,10 +638,7 @@ public sealed class MainWindowViewModel : ViewModelBase
             }
             catch (Exception ex)
             {
-                Avalonia.Threading.Dispatcher.UIThread.Post(() =>
-                {
-                    StatusText = $"Failed to load profile: {ex.Message}";
-                });
+                Debug.WriteLine($"Failed to load profile: {ex.Message}");
             }
         };
 
@@ -534,7 +647,7 @@ public sealed class MainWindowViewModel : ViewModelBase
             ClientConfig config = ConfigManager.Load();
             string servers = string.Join("\n", config.SavedServers.Select(s =>
                 $"{s.Name} ({s.Url}) - {s.Username ?? "?"}"));
-            StatusText = servers;
+            ShowSystemMessage(servers);
             return Task.CompletedTask;
         };
     }
@@ -570,7 +683,7 @@ public sealed class MainWindowViewModel : ViewModelBase
                 defaultChannel ??= serverVm.Channels.FirstOrDefault();
                 serverVm.SelectedChannel = defaultChannel;
 
-                StatusText = $"Connected to {server.Name}";
+                ShowSystemMessage($"Connected to {server.Name}");
             });
         };
 
@@ -582,7 +695,7 @@ public sealed class MainWindowViewModel : ViewModelBase
                 if (Sidebar.Servers.Count == 0)
                 {
                     Chat.ClearMessages();
-                    StatusText = "Ready";
+                    Debug.WriteLine("Ready");
                 }
             });
         };
@@ -602,7 +715,7 @@ public sealed class MainWindowViewModel : ViewModelBase
 
                     if (!server.IsConnected)
                     {
-                        StatusText = $"Disconnected from {server.Name}";
+                        ShowSystemMessage($"Disconnected from {server.Name}");
                     }
                 }
             });
@@ -611,8 +724,11 @@ public sealed class MainWindowViewModel : ViewModelBase
         ConnectionService.MessageReceived += (serverUrl, message) =>
         {
             string? username = ConnectionService.GetCurrentUsername(serverUrl);
-            bool isMention = !string.IsNullOrEmpty(username)
-                && message.Content.Contains($"@{username}", StringComparison.OrdinalIgnoreCase);
+            bool isReplyToMe = !string.IsNullOrEmpty(username)
+                && string.Equals(message.ReplyTo?.SenderUsername, username, StringComparison.OrdinalIgnoreCase);
+            bool isMention = isReplyToMe
+                || (!string.IsNullOrEmpty(username)
+                    && message.Content.Contains($"@{username}", StringComparison.OrdinalIgnoreCase));
 
             Avalonia.Threading.Dispatcher.UIThread.Post(() =>
             {
@@ -653,14 +769,31 @@ public sealed class MainWindowViewModel : ViewModelBase
             }
         };
 
-        ConnectionService.ErrorOccurred += (serverUrl, error) =>
+        ConnectionService.ChannelDeleted += (serverUrl, channelName) =>
         {
             Avalonia.Threading.Dispatcher.UIThread.Post(() =>
             {
-                StatusText = $"Error: {error}";
+                ServerViewModel? serverVm = Sidebar.GetServer(serverUrl);
+                if (serverVm is null) return;
+
+                ChannelViewModel? channelVm = serverVm.Channels
+                    .FirstOrDefault(c => string.Equals(c.Name, channelName, StringComparison.OrdinalIgnoreCase));
+                if (channelVm is not null)
+                    serverVm.Channels.Remove(channelVm);
+
+                if (string.Equals(channelName, Chat.CurrentChannelName, StringComparison.OrdinalIgnoreCase)
+                    && string.Equals(serverUrl, Chat.CurrentServerUrl, StringComparison.OrdinalIgnoreCase))
+                {
+                    Chat.ClearMessages();
+                }
             });
         };
 
+        ConnectionService.ErrorOccurred += (serverUrl, error) =>
+        {
+            Debug.WriteLine($"Error: {error}");
+        };
+
         ConnectionService.ChannelAdded += (serverUrl, channel) =>
         {
             Avalonia.Threading.Dispatcher.UIThread.Post(() =>
@@ -674,6 +807,25 @@ public sealed class MainWindowViewModel : ViewModelBase
         };
     }
 
+    private async Task HandleSendTextAsync(string text)
+    {
+        string serverUrl = GetCurrentServerUrl();
+        string channelName = Chat.CurrentChannelName;
+        if (string.IsNullOrEmpty(serverUrl) || string.IsNullOrEmpty(channelName))
+        {
+            return;
+        }
+
+        try
+        {
+            await ConnectionService.SendMessageAsync(serverUrl, channelName, text);
+        }
+        catch (Exception ex)
+        {
+            Debug.WriteLine($"Send failed: {ex.Message}");
+        }
+    }
+
     private async Task RefreshOnlineUsersAsync(string serverUrl, string channelName)
     {
         try
@@ -695,18 +847,12 @@ public sealed class MainWindowViewModel : ViewModelBase
         CommandResult result = await _commandHandler.HandleAsync(commandText);
         if (result.Message is not null)
         {
-            Chat.Messages.Add(new MessageViewModel(new MessageModel(
-                Guid.NewGuid().ToString("N"),
-                new UserModel("system", "System"),
-                DateTimeOffset.Now,
-                result.Message,
-                Chat.CurrentChannelName,
-                Chat.CurrentServerUrl)));
+            ShowSystemMessage(result.Message);
         }
         return result.Message;
     }
 
-    private void HandleSendRequested(string serverUrl, string text, IReadOnlyList<string> filePaths)
+    private void HandleSendRequested(string serverUrl, string text, IReadOnlyList<string> filePaths, Guid? replyToMessageId)
     {
         if (string.IsNullOrEmpty(Chat.CurrentChannelName))
         {
@@ -720,13 +866,10 @@ public sealed class MainWindowViewModel : ViewModelBase
                 try
                 {
                     await ConnectionService.SendMessageWithAttachmentsAsync(serverUrl, Chat.CurrentChannelName, text, filePaths);
-                    Avalonia.Threading.Dispatcher.UIThread.Post(() =>
-                        StatusText = "Message sent");
                 }
                 catch (Exception ex)
                 {
-                    Avalonia.Threading.Dispatcher.UIThread.Post(() =>
-                        StatusText = $"Send failed: {ex.Message}");
+                    Debug.WriteLine($"Send failed: {ex.Message}");
                 }
             });
             return;
@@ -742,14 +885,11 @@ public sealed class MainWindowViewModel : ViewModelBase
         {
             try
             {
-                await ConnectionService.SendMessageAsync(serverUrl, Chat.CurrentChannelName, text);
+                await ConnectionService.SendMessageAsync(serverUrl, Chat.CurrentChannelName, text, replyToMessageId);
             }
             catch (Exception ex)
             {
-                Avalonia.Threading.Dispatcher.UIThread.Post(() =>
-                {
-                    StatusText = $"Send failed: {ex.Message}";
-                });
+                Debug.WriteLine($"Send failed: {ex.Message}");
             }
         });
     }
@@ -770,14 +910,12 @@ public sealed class MainWindowViewModel : ViewModelBase
 
         try
         {
-            StatusText = "Creating channel...";
-
             ChannelDto? channel = await ConnectionService.CreateChannelAsync(
                 server.ServerUrl, dialog.ResultName!, dialog.ResultTopic, dialog.ResultIsPublic, dialog.ResultPassword);
 
             if (channel is null)
             {
-                StatusText = "Failed to create channel";
+                ShowSystemMessage("Failed to create channel");
                 return;
             }
 
@@ -804,7 +942,7 @@ public sealed class MainWindowViewModel : ViewModelBase
                         channelVm.AddMessage(msg);
                     }
 
-                    StatusText = $"Created #{channel.Name}";
+                    ShowSystemMessage($"Created #{channel.Name}");
                 });
             }
         }
@@ -826,7 +964,7 @@ public sealed class MainWindowViewModel : ViewModelBase
         string channelName = Chat.CurrentChannelName;
         if (string.IsNullOrEmpty(channelName) || !string.Equals(Chat.CurrentServerUrl, server.ServerUrl, StringComparison.OrdinalIgnoreCase))
         {
-            StatusText = "No channel selected on this server";
+            Debug.WriteLine("No channel selected on this server");
             return;
         }
 
@@ -864,7 +1002,7 @@ public sealed class MainWindowViewModel : ViewModelBase
                     ?? server.Channels.FirstOrDefault();
                 server.SelectedChannel = defaultChannel;
 
-                StatusText = $"Deleted #{channelName}";
+                ShowSystemMessage($"Deleted #{channelName}");
             });
         }
         catch (Exception ex)
@@ -1008,7 +1146,7 @@ public sealed class MainWindowViewModel : ViewModelBase
                             channel.IsLocked = false;
                             Chat.Composer.IsConnected = isServerConnected;
 
-                            if (channel.Messages.Count == 0)
+                            if (!channel.Messages.Any(m => m.AuthorName != "System"))
                             {
                                 foreach (MessageModel msg in joinResult.History)
                                 {
@@ -1109,7 +1247,7 @@ public sealed class MainWindowViewModel : ViewModelBase
         catch (Exception ex)
         {
             serverVm.IsConnecting = false;
-            StatusText = $"Auto-connect failed for {saved.Name}: {ex.Message}";
+            Debug.WriteLine($"Auto-connect failed for {saved.Name}: {ex.Message}");
         }
     }
 
@@ -1147,7 +1285,7 @@ public sealed class MainWindowViewModel : ViewModelBase
         }
         catch (Exception ex)
         {
-            StatusText = $"Disconnect error: {ex.Message}";
+            Debug.WriteLine($"Disconnect error: {ex.Message}");
         }
     }
 
@@ -1159,7 +1297,7 @@ public sealed class MainWindowViewModel : ViewModelBase
         }
         catch (Exception ex)
         {
-            StatusText = $"Remove error: {ex.Message}";
+            Debug.WriteLine($"Remove error: {ex.Message}");
         }
     }
 

src/Decho/ViewModels/MessageComposerViewModel.cs

@@ -10,7 +10,7 @@ namespace Decho.ViewModels;
 
 public sealed class MessageComposerViewModel : ViewModelBase
 {
-    public event Action<string, string, IReadOnlyList<string>>? SendRequested;
+    public event Action<string, string, IReadOnlyList<string>, Guid?>? SendRequested;
 
     public event Func<string, Task<string?>>? CommandRequested;
 
@@ -48,6 +48,27 @@ public sealed class MessageComposerViewModel : ViewModelBase
 
     public AutocompleteController Autocomplete { get; }
 
+    public MessageViewModel? ReplyTarget
+    {
+        get => field;
+        set
+        {
+            this.RaiseAndSetIfChanged(ref field, value);
+            this.RaisePropertyChanged(nameof(HasReplyTarget));
+            ReplySummary = value is not null
+                ? $"\u21A9 Replying to {value.AuthorName}: {value.Content[..Math.Min(value.Content.Length, 80)]}"
+                : string.Empty;
+        }
+    }
+
+    public bool HasReplyTarget => ReplyTarget is not null;
+
+    public string ReplySummary
+    {
+        get;
+        private set => this.RaiseAndSetIfChanged(ref field, value);
+    } = string.Empty;
+
     public MessageComposerViewModel()
     {
         AutocompleteProvider mentionProvider = new(
@@ -153,6 +174,11 @@ public sealed class MessageComposerViewModel : ViewModelBase
         Autocomplete.Reset();
     }
 
+    public void ClearReplyTarget()
+    {
+        ReplyTarget = null;
+    }
+
     private void UpdateStagedSummary()
     {
         this.RaisePropertyChanged(nameof(HasStagedFiles));
@@ -181,6 +207,9 @@ public sealed class MessageComposerViewModel : ViewModelBase
         StagedFiles.Clear();
         UpdateStagedSummary();
 
-        SendRequested?.Invoke(ServerUrl, text, filePaths);
+        Guid? replyToId = ReplyTarget is not null && Guid.TryParse(ReplyTarget.Model.Id, out Guid rid) ? rid : null;
+        ClearReplyTarget();
+
+        SendRequested?.Invoke(ServerUrl, text, filePaths, replyToId);
     }
 }

src/Decho/ViewModels/MessageViewModel.cs

@@ -36,6 +36,16 @@ public sealed class MessageViewModel(MessageModel model) : ViewModelBase
 
     public string Content => Model.Content;
 
+    public bool IsAction => Model.Content.StartsWith("/me ", StringComparison.Ordinal);
+
+    public string ActionText => IsAction ? Model.Content[4..] : Model.Content;
+
+    public string DisplayContent => IsAction ? $"* {AuthorName} {ActionText}" : Model.Content;
+
+    public ReplyRefDto? ReplyTo => Model.ReplyTo;
+
+    public bool HasReply => ReplyTo is not null;
+
     public string? ServerUrl => Model.ServerUrl;
 
     public Dictionary<string, Bitmap> ImageCache { get; } = [];

src/Decho/Views/MessageComposerView.axaml

@@ -5,7 +5,7 @@
              xmlns:i="https://github.com/projektanker/icons.avalonia"
              x:Class="Decho.Views.MessageComposerView"
              x:DataType="vm:MessageComposerViewModel">
-    <Grid RowDefinitions="Auto,*">
+    <Grid RowDefinitions="Auto,Auto,*">
         <Border IsVisible="{Binding HasStagedFiles}"
                 Background="{DynamicResource UiTheme02}"
                 CornerRadius="4"
@@ -48,7 +48,26 @@
                 </ItemsControl>
             </DockPanel>
         </Border>
-        <Grid Grid.Row="1">
+        <Border Grid.Row="1"
+                IsVisible="{Binding HasReplyTarget}"
+                Background="{DynamicResource UiTheme02}"
+                CornerRadius="4"
+                Padding="6"
+                Margin="0 0 0 4">
+            <DockPanel>
+                <Button DockPanel.Dock="Right"
+                        Content="x"
+                        FontSize="11"
+                        Padding="4 0"
+                        Cursor="Hand"
+                        Click="OnCancelReplyClick" />
+                <TextBlock VerticalAlignment="Center"
+                           FontSize="12"
+                           Opacity="0.6"
+                           Text="{Binding ReplySummary}" />
+            </DockPanel>
+        </Border>
+        <Grid Grid.Row="2">
             <Grid.ColumnDefinitions>
                 <ColumnDefinition Width="*" />
                 <ColumnDefinition Width="Auto" />

src/Decho/Views/MessageComposerView.axaml.cs

@@ -169,6 +169,12 @@ public partial class MessageComposerView : UserControl
         vm?.ClearStagedFiles();
     }
 
+    private void OnCancelReplyClick(object? sender, RoutedEventArgs e)
+    {
+        MessageComposerViewModel? vm = this.GetDataContext<MessageComposerViewModel>();
+        vm?.ClearReplyTarget();
+    }
+
     private void OnDragOver(object? sender, DragEventArgs e)
     {
 #pragma warning disable CS0618

src/Decho/Views/MessageItemView.axaml

@@ -23,7 +23,21 @@
 						   Text="{Binding TimeText}"
 						   FontSize="10"
 						   Margin="5 0 0 0" />
+				<TextBlock VerticalAlignment="Top"
+						   Text="↩"
+						   FontSize="10"
+						   Margin="5 0 0 0"
+						   Opacity="0.3"
+						   Cursor="Hand"
+						   PointerPressed="OnReplyPointerPressed" />
 			</StackPanel>
+			<TextBlock x:Name="ReplyQuote"
+					   VerticalAlignment="Top"
+					   TextWrapping="Wrap"
+					   FontSize="11"
+					   Opacity="0.5"
+					   IsVisible="{Binding HasReply}"
+					   PointerPressed="OnReplyQuotePointerPressed" />
 			<TextBlock x:Name="MessageContent"
 					   VerticalAlignment="Top"
 					   TextWrapping="Wrap"

src/Decho/Views/MessageItemView.axaml.cs

@@ -59,7 +59,13 @@ public partial class MessageItemView : UserControl
         if (DataContext is MessageViewModel msg)
         {
             _loadedMessageId = msg.Model.Id;
-            BuildMessageInlines(msg.Content);
+            BuildMessageInlines(msg.DisplayContent);
+
+            TextBlock? replyQuote = ReplyQuote;
+            if (replyQuote is not null && msg.ReplyTo is { } reply)
+            {
+                replyQuote.Text = $"\u2514 {reply.SenderUsername}: {reply.Content}";
+            }
         }
     }
 
@@ -385,4 +391,40 @@ public partial class MessageItemView : UserControl
         ImageViewerWindow viewer = new ImageViewerWindow(bitmap, att.FileName, downloadAsync);
         await viewer.ShowDialog(parent);
     }
+
+    private void OnReplyPointerPressed(object? sender, Avalonia.Input.PointerPressedEventArgs e)
+    {
+        if (DataContext is not MessageViewModel msg)
+            return;
+
+        MainWindowViewModel? mainVm = this.GetMainWindowViewModel();
+        if (mainVm is null)
+            return;
+
+        mainVm.Chat.Composer.ReplyTarget = msg;
+    }
+
+    private void OnReplyQuotePointerPressed(object? sender, Avalonia.Input.PointerPressedEventArgs e)
+    {
+        if (DataContext is not MessageViewModel msg || msg.ReplyTo is null)
+            return;
+
+        MainWindowViewModel? mainVm = this.GetMainWindowViewModel();
+        if (mainVm is null)
+            return;
+
+        string serverUrl = ResolveServerUrl();
+        ServerViewModel? serverVm = mainVm.Sidebar.GetServer(serverUrl);
+        if (serverVm is null)
+            return;
+
+        ChannelViewModel? channel = serverVm.Channels.FirstOrDefault(c =>
+            string.Equals(c.Name, msg.Model.ChannelName, StringComparison.OrdinalIgnoreCase));
+        if (channel is null)
+            return;
+
+        // Switch to the channel containing the original message
+        if (!string.Equals(channel.Name, mainVm.Chat.CurrentChannelName, StringComparison.OrdinalIgnoreCase))
+            mainVm.Sidebar.SelectedChannel = channel;
+    }
 }