feat: handle CataloggerError results in interaction responder

Catalogger.Backend/Bot/Responders/CustomInteractionResponder.cs

@@ -19,17 +19,21 @@ using Remora.Commands.Services;
 using Remora.Commands.Tokenization;
 using Remora.Commands.Trees;
 using Remora.Discord.API.Abstractions.Gateway.Events;
+using Remora.Discord.API.Abstractions.Objects;
 using Remora.Discord.API.Abstractions.Rest;
+using Remora.Discord.API.Objects;
 using Remora.Discord.Commands.Responders;
 using Remora.Discord.Commands.Services;
 using Remora.Discord.Gateway.Responders;
+using Remora.Rest.Core;
 using Remora.Results;
 using Serilog.Context;
 
 namespace Catalogger.Backend.Bot.Responders;
 
 /// <summary>
-/// Wrapper for Remora.Discord's default interaction responder, that ignores all events if test mode is enabled.
+/// Wrapper for Remora.Discord's default interaction responder, that ignores all events if test mode is enabled,
+/// and handles <see cref="CataloggerError" /> results returned by commands.
 /// </summary>
 public class CustomInteractionResponder(
     Config config,
@@ -87,6 +91,38 @@ public class CustomInteractionResponder(
             true
         );
 
-        return await _inner.RespondAsync(evt, ct);
+        var result = await _inner.RespondAsync(evt, ct);
+        if (result.Error is not CataloggerError cataloggerError)
+            return result;
+
+        return await interactionAPI.CreateInteractionResponseAsync(
+            evt.ID,
+            evt.Token,
+            new InteractionResponse(
+                Type: InteractionCallbackType.ChannelMessageWithSource,
+                Data: new Optional<OneOf.OneOf<
+                    IInteractionMessageCallbackData,
+                    IInteractionAutocompleteCallbackData,
+                    IInteractionModalCallbackData
+                >>(
+                    new InteractionMessageCallbackData(
+                        Embeds: new Optional<IReadOnlyList<IEmbed>>(
+                            [
+                                new Embed(
+                                    Colour: DiscordUtils.Red,
+                                    Title: "Something went wrong",
+                                    Description: $"""
+                                    Something went wrong while running this command.
+                                    > {cataloggerError.Message}
+                                    Please try again later.
+                                    """
+                                ),
+                            ]
+                        )
+                    )
+                )
+            ),
+            ct: ct
+        );
     }
 }