Add support for rendering message embeds

src/Decho/Converters/StringConverters.cs

@@ -0,0 +1,23 @@
+using Avalonia.Data.Converters;
+
+using System.Globalization;
+
+namespace Decho.Converters;
+
+public static class StringConverters
+{
+    public static readonly IValueConverter IsNotNullOrEmpty = new IsNotNullOrEmptyConverter();
+
+    private sealed class IsNotNullOrEmptyConverter : IValueConverter
+    {
+        public object? Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
+        {
+            return value is string s && !string.IsNullOrEmpty(s);
+        }
+
+        public object? ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
+        {
+            throw new NotSupportedException();
+        }
+    }
+}

src/Decho/Models/MessageModel.cs

@@ -10,7 +10,8 @@ public sealed class MessageModel(
     string channelName,
     string? serverUrl = null,
     List<AttachmentDto>? attachments = null,
-    ReplyRefDto? replyTo = null)
+    ReplyRefDto? replyTo = null,
+    List<EmbedDto>? embeds = null)
 {
     public string Id { get; } = id;
 
@@ -27,4 +28,6 @@ public sealed class MessageModel(
     public List<AttachmentDto> Attachments { get; } = attachments ?? [];
 
     public ReplyRefDto? ReplyTo { get; } = replyTo;
+
+    public List<EmbedDto> Embeds { get; } = embeds ?? [];
 }

src/Decho/Services/ChannelService.cs

@@ -334,6 +334,7 @@ internal sealed class ChannelService : IChannelService
             dto.ChannelName,
             entry.Server.ServerUrl,
             attachments,
-            dto.ReplyTo);
+            dto.ReplyTo,
+            dto.Embeds);
     }
 }

src/Decho/Services/ConnectionService.cs

@@ -1,6 +1,3 @@
-using Avalonia;
-using Avalonia.Controls.ApplicationLifetimes;
-
 using Decho.Models;
 
 using EchoHub.Client.Config;
@@ -9,10 +6,6 @@ using EchoHub.Client.UI.Dialogs;
 using EchoHub.Core.Constants;
 using EchoHub.Core.DTOs;
 
-using MsBox.Avalonia;
-using MsBox.Avalonia.Base;
-using MsBox.Avalonia.Enums;
-
 using System.Collections.ObjectModel;
 using System.Diagnostics;
 
@@ -167,7 +160,8 @@ public sealed class ConnectionService : IConnectionService
             dto.ChannelName,
             entry.Server.ServerUrl,
             attachments,
-            dto.ReplyTo);
+            dto.ReplyTo,
+            dto.Embeds ?? []);
     }
 
     internal ServerConnection? GetConnection(string serverUrl)

src/Decho/Services/IChannelService.cs

@@ -45,4 +45,4 @@ public interface IChannelService
     Task SendUrlAsync(string serverUrl, string channelName, string url, string? size);
 
     Task<List<MessageModel>> GetHistoryAsync(string serverUrl, string channelName, int count = 50, int offset = 0);
-}
+}

src/Decho/ViewModels/MessageViewModel.cs

@@ -54,6 +54,10 @@ public sealed class MessageViewModel(MessageModel model) : ViewModelBase
 
     public bool HasAttachments => Attachments.Count > 0;
 
+    public IReadOnlyList<EmbedDto> Embeds => Model.Embeds;
+
+    public bool HasEmbeds => Embeds.Count > 0;
+
     public bool ShowContent => !string.IsNullOrEmpty(Content);
 
     public string TimeText

src/Decho/Views/MessageItemView.axaml

@@ -2,6 +2,7 @@
 			 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 			 xmlns:vm="using:Decho.ViewModels"
 			 xmlns:dto="using:EchoHub.Core.DTOs"
+			 xmlns:conv="using:Decho.Converters"
 			 x:Class="Decho.Views.MessageItemView"
 			 x:DataType="vm:MessageViewModel">
 	<Grid Margin="5" ColumnDefinitions="Auto, *">
@@ -67,6 +68,35 @@
 					</DataTemplate>
 				</ItemsControl.ItemTemplate>
 			</ItemsControl>
+			<ItemsControl ItemsSource="{Binding Embeds}"
+						  IsVisible="{Binding HasEmbeds}"
+						  Margin="0 4 0 0">
+				<ItemsControl.ItemTemplate>
+					<DataTemplate x:DataType="dto:EmbedDto">
+						<Border BorderThickness="3 0 0 0"
+								BorderBrush="{Binding ThemeColor, TargetNullValue=Gray}"
+								CornerRadius="4"
+								Background="{DynamicResource UiTheme01}"
+								Padding="10"
+								Margin="0 2 0 2">
+							<StackPanel Spacing="2">
+								<TextBlock Text="{Binding SiteName}"
+										   FontSize="11"
+										   Opacity="0.6"
+										   IsVisible="{Binding SiteName, Converter={x:Static conv:StringConverters.IsNotNullOrEmpty}}" />
+								<TextBlock Text="{Binding Title}"
+										   FontWeight="Bold"
+										   TextWrapping="Wrap" />
+								<TextBlock Text="{Binding Description}"
+										   FontSize="12"
+										   Opacity="0.8"
+										   TextWrapping="Wrap"
+										   IsVisible="{Binding Description, Converter={x:Static conv:StringConverters.IsNotNullOrEmpty}}" />
+							</StackPanel>
+						</Border>
+					</DataTemplate>
+				</ItemsControl.ItemTemplate>
+			</ItemsControl>
 		</StackPanel>
 	</Grid>
 </UserControl>

src/Decho/Views/MessageItemView.axaml.cs

@@ -267,7 +267,7 @@ public partial class MessageItemView : UserControl
         }
         catch
         {
-            // Image failed to load — filename is shown as fallback
+            // Image failed to load filename is shown as fallback
         }
     }