added logging for admin events

thorn/Program.cs

@@ -45,8 +45,10 @@ private static async Task Main()
             {
                 LogLevel = LogSeverity.Info,
                 MessageCacheSize = 50,
+                AlwaysDownloadUsers = true,
                 GatewayIntents = GatewayIntents.MessageContent | GatewayIntents.Guilds | GatewayIntents.GuildMessages |
-                                 GatewayIntents.GuildMessageReactions
+                                 GatewayIntents.GuildMessageReactions | GatewayIntents.GuildMembers |
+                                 GatewayIntents.GuildBans
             };
 
             config.Token = builder.Configuration["token"]!;
@@ -61,6 +63,7 @@ private static async Task Main()
 
         builder.Services.AddHostedService<InteractionHandler>();
         builder.Services.AddHostedService<ReactionHandler>();
+        builder.Services.AddHostedService<AdminLogService>();
 
         builder.Services.AddSingleton<RssJob>();
         builder.Services.AddSingleton<ReminderJob>();

thorn/Services/AdminLogService.cs

@@ -0,0 +1,182 @@
+using System;
+using System.Globalization;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Discord;
+using Discord.Addons.Hosting;
+using Discord.Rest;
+using Discord.WebSocket;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
+
+namespace thorn.Services;
+
+public class AdminLogService(DiscordSocketClient client, IConfiguration config, ILogger<AdminLogService> logger)
+    : DiscordClientService(client, logger)
+{
+    private readonly DiscordSocketClient _client = client;
+
+    private readonly ulong _consoleChannelId = ulong.Parse(
+        config["channels:adminConsole"] ?? throw new Exception("AdminConsole channel is not configured"), NumberStyles.Any);
+
+    private static readonly TimeSpan AuditLookback = TimeSpan.FromSeconds(15);
+
+    protected override Task ExecuteAsync(CancellationToken cancellationToken)
+    {
+        _client.UserLeft += OnUserLeft;
+        _client.UserBanned += OnUserBanned;
+        _client.UserUnbanned += OnUserUnbanned;
+        _client.GuildMemberUpdated += OnGuildMemberUpdated;
+        return Task.CompletedTask;
+    }
+
+    private async Task OnUserLeft(SocketGuild guild, SocketUser user)
+    {
+        // kicks and bans both trigger a UserLeft event; the audit log tells us which one happened
+        if (await GetRecentAuditEntry(guild, ActionType.Ban, user.Id) is not null)
+            return; // a ban is reported separately by OnUserBanned
+
+        var kick = await GetRecentAuditEntry(guild, ActionType.Kick, user.Id);
+        if (kick is not null)
+        {
+            await LogKick(user, kick);
+            return;
+        }
+
+        await LogLeft(user);
+    }
+
+    private async Task LogLeft(SocketUser user)
+    {
+        var embed = BaseEmbed(user)
+            .WithTitle($"Týpek to lývnul (｡>﹏<)")
+            .AddField("Uživatel", $"{user.Mention} ({user})")
+            .AddField("ID", user.Id.ToString())
+            .Build();
+
+        await SendLog(embed);
+    }
+
+    private async Task LogKick(SocketUser user, RestAuditLogEntry entry)
+    {
+        var embed = BaseEmbed(user)
+            .WithTitle("Někdo dostal kopanec, čau! (´•︵•`)")
+            .AddField("Uživatel", $"{user.Mention} ({user})")
+            .AddField("ID", user.Id.ToString())
+            .AddField("Kopanec provedl", entry.User?.Mention ?? "???", inline: true)
+            .AddField("Důvod", string.IsNullOrWhiteSpace(entry.Reason) ? "neuveden" : entry.Reason, inline: true)
+            .Build();
+
+        await SendLog(embed);
+    }
+
+    private async Task OnUserBanned(SocketUser user, SocketGuild guild)
+    {
+        var entry = await GetRecentAuditEntry(guild, ActionType.Ban, user.Id);
+
+        var embed = BaseEmbed(user)
+            .WithTitle("Někdo dostal banán, čau! (ㅠ﹏ㅠ)")
+            .AddField("Uživatel", $"{user.Mention} ({user})")
+            .AddField("ID", user.Id.ToString())
+            .AddField("Banán dal", entry?.User?.Mention ?? "???", inline: true)
+            .AddField("Důvod", string.IsNullOrWhiteSpace(entry?.Reason) ? "neuveden" : entry.Reason, inline: true)
+            .Build();
+
+        await SendLog(embed);
+    }
+
+    private async Task OnUserUnbanned(SocketUser user, SocketGuild guild)
+    {
+        var entry = await GetRecentAuditEntry(guild, ActionType.Unban, user.Id);
+
+        var embed = BaseEmbed(user)
+            .WithColor(Color.Green)
+            .WithTitle("Někomu odpustili banán, vítej zpět! (ﾉ◕ヮ◕)ﾉ*:・ﾟ✧")
+            .AddField("Uživatel", $"{user.Mention} ({user})")
+            .AddField("ID", user.Id.ToString())
+            .AddField("Banán odebral", entry?.User?.Mention ?? "???", inline: true)
+            .Build();
+
+        await SendLog(embed);
+    }
+
+    private async Task OnGuildMemberUpdated(Cacheable<SocketGuildUser, ulong> before, SocketGuildUser after)
+    {
+        if (!before.HasValue) return;
+        var old = before.Value;
+
+        var added = after.Roles.Except(old.Roles).Where(r => !r.IsEveryone).ToList();
+        var removed = old.Roles.Except(after.Roles).Where(r => !r.IsEveryone).ToList();
+
+        if (added.Count == 0 && removed.Count == 0) return;
+
+        var diff = string.Join("\n",
+            added.OrderByDescending(r => r.Position).Select(r => $"`+` {r.Mention}")
+                .Concat(removed.OrderByDescending(r => r.Position).Select(r => $"`-` {r.Mention}")));
+
+        var entry = await GetRecentAuditEntry(after.Guild, ActionType.MemberRoleUpdated, after.Id);
+
+        var embed = BaseEmbed(after)
+            .WithTitle("Zmšna rolí ^_^")
+            .AddField("Aktuální role", FormatRoles(after.Roles))
+            .AddField("Staré role", FormatRoles(old.Roles))
+            .AddField("Změna", diff)
+            .AddField("Změnu provedl", entry?.User?.Mention ?? "kdosi", inline: true)
+            .Build();
+
+        await SendLog(embed);
+    }
+
+    private static string FormatRoles(System.Collections.Generic.IEnumerable<SocketRole> roles)
+    {
+        var mentions = roles.Where(r => !r.IsEveryone)
+            .OrderByDescending(r => r.Position)
+            .Select(r => r.Mention)
+            .ToList();
+        return mentions.Count > 0 ? string.Join(" ", mentions) : "žádné";
+    }
+
+    private static EmbedBuilder BaseEmbed(SocketUser user) =>
+        new EmbedBuilder()
+            .WithAuthor(user.ToString(), user.GetAvatarUrl() ?? user.GetDefaultAvatarUrl())
+            .WithColor(Color.Red)
+            .WithCurrentTimestamp();
+
+    private async Task<RestAuditLogEntry?> GetRecentAuditEntry(SocketGuild guild, ActionType type, ulong targetId)
+    {
+        await Task.Delay(500); // give Discord a moment to write the audit log
+        try
+        {
+            var logs = await guild.GetAuditLogsAsync(5, actionType: type).FlattenAsync();
+            return logs.FirstOrDefault(e =>
+                GetAuditTargetId(e) == targetId &&
+                DateTimeOffset.UtcNow - e.CreatedAt < AuditLookback);
+        }
+        catch (Exception ex)
+        {
+            Logger.LogWarning(ex, "Failed to read audit logs for {Action}", type);
+            return null;
+        }
+    }
+
+    private static ulong? GetAuditTargetId(RestAuditLogEntry entry) => entry.Data switch
+    {
+        BanAuditLogData ban => ban.Target.Id,
+        UnbanAuditLogData unban => unban.Target.Id,
+        KickAuditLogData kick => kick.Target.Id,
+        MemberRoleAuditLogData roleUpdate => roleUpdate.Target.Id,
+        _ => null
+    };
+
+    private async Task SendLog(Embed embed)
+    {
+        if (_client.GetChannel(_consoleChannelId) is not IMessageChannel channel)
+        {
+            Logger.LogWarning("Console channel {ChannelId} not found, skipping log", _consoleChannelId);
+            return;
+        }
+
+        await channel.SendMessageAsync(embed: embed);
+    }
+}