feat: guild update event

Catalogger.Backend/Bot/Responders/Guilds/GuildUpdateResponder.cs

@@ -0,0 +1,122 @@
+// Copyright (C) 2021-present sam (starshines.gay)
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published
+// by the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+using Catalogger.Backend.Cache.InMemoryCache;
+using Catalogger.Backend.Database;
+using Catalogger.Backend.Database.Queries;
+using Catalogger.Backend.Extensions;
+using Catalogger.Backend.Services;
+using Remora.Discord.API;
+using Remora.Discord.API.Abstractions.Gateway.Events;
+using Remora.Discord.Extensions.Embeds;
+using Remora.Discord.Gateway.Responders;
+using Remora.Results;
+
+namespace Catalogger.Backend.Bot.Responders.Guilds;
+
+public class GuildUpdateResponder(
+    ILogger logger,
+    DatabaseContext db,
+    GuildCache guildCache,
+    UserCache userCache,
+    WebhookExecutorService webhookExecutor
+) : IResponder<IGuildUpdate>
+{
+    private readonly ILogger _logger = logger.ForContext<GuildUpdateResponder>();
+
+    public async Task<Result> RespondAsync(IGuildUpdate evt, CancellationToken ct = default)
+    {
+        try
+        {
+            if (!guildCache.TryGet(evt.ID, out var oldGuild))
+            {
+                _logger.Warning(
+                    "Guild {GuildId} not found in cache, ignoring event and adding it to cache",
+                    evt.ID
+                );
+                return Result.Success;
+            }
+
+            var embed = new EmbedBuilder()
+                .WithTitle("Server updated")
+                .WithColour(DiscordUtils.Blue)
+                .WithCurrentTimestamp();
+
+            if (evt.Name != oldGuild.Name)
+                embed.AddField("Name", $"**Before:** {oldGuild.Name}\n**After:** {evt.Name}");
+
+            if (!Equals(evt.Icon, oldGuild.Icon))
+            {
+                if (evt.Icon != null)
+                    embed.WithThumbnailUrl(
+                        CDN.GetGuildIconUrl(evt, imageSize: 1024).GetOrThrow().ToString()
+                    );
+
+                if (evt.Icon != null && oldGuild.Icon == null)
+                {
+                    embed.AddField(
+                        "Icon added",
+                        $"[Link]({CDN.GetGuildIconUrl(evt, imageSize: 1024).GetOrThrow()})"
+                    );
+                }
+                else if (evt.Icon != null && oldGuild.Icon != null)
+                {
+                    embed.AddField(
+                        "Icon changed",
+                        $"[Link]({CDN.GetGuildIconUrl(evt, imageSize: 1024).GetOrThrow()})"
+                    );
+                }
+                else
+                {
+                    embed.AddField("Icon removed", "*(old icon no longer available, sorry)*");
+                }
+            }
+
+            if (evt.OwnerID != oldGuild.OwnerID)
+            {
+                embed.AddField(
+                    "Ownership transferred",
+                    $"""
+                    **Before:** {userCache.TryFormatUserAsync(oldGuild.OwnerID)}
+                    **After:** {userCache.TryFormatUserAsync(evt.OwnerID)}
+                    """
+                );
+            }
+
+            if (embed.Fields.Count != 0)
+            {
+                var guildConfig = await db.GetGuildAsync(evt.ID, ct);
+                webhookExecutor.QueueLog(
+                    guildConfig,
+                    LogChannelType.GuildUpdate,
+                    embed.Build().GetOrThrow()
+                );
+            }
+            else
+            {
+                _logger.Debug(
+                    "Guild update event for {GuildId} had nothing we want to log, not sending embed",
+                    evt.ID
+                );
+            }
+
+            return Result.Success;
+        }
+        finally
+        {
+            guildCache.Set(evt);
+        }
+    }
+}

Catalogger.Backend/Extensions/DiscordExtensions.cs

@@ -36,6 +36,7 @@ public static class DiscordExtensions
             : $"{user.Username.Value}#{discriminator:0000}";
     }
 
+    // TODO: replace these avatar URL methods with the built-in CDN.* methods?
     public static string AvatarUrl(this IUser user, int size = 256)
     {
         if (user.Avatar != null)