Implement automatic spam detection and banning feature

.github/config.json

@@ -74,6 +74,14 @@
             "sessionToken": "",
             "leaderBoardJsonUrl": "",
             "userMap": {}
+        },
+        "autoban": {
+            "enabled": true,
+            "dryRun": true,
+            "deleteThreshold": 40,
+            "banThreshold": 60,
+            "banDurationHours": 24,
+            "timeWindowDuration": "PT5M"
         }
     },
 
@@ -90,7 +98,8 @@
         "votesChannelId": "893179191556706384",
         "botSpamChannelId": "893179191556706387",
         "hauptwoisTextChannelId": "893179191825162371",
-        "roleAssignerChannelId": "893179190881452115"
+        "roleAssignerChannelId": "893179190881452115",
+        "spamLogChannelId": "1513948506266538275"
     },
 
     "voiceChannel": {

.github/workflows/CI.yaml

@@ -126,13 +126,13 @@ jobs:
           DISCORD_CLIENT_ID: ${{ secrets.CI_CLIENT_ID }}
           PR_ID: ${{ github.event.number }}
         run: |
-          envsubst < .github/config.json > config.json
+          envsubst < .github/config.json > config-ephemeral.json
 
       - name: Read config.json
         id: config
         uses: juliangruber/read-file-action@v1
         with:
-          path: ./config.json
+          path: ./config-ephemeral.json
 
       - name: Build args
         id: args

config.template.json

@@ -78,6 +78,20 @@
             "sessionToken": "",
             "leaderBoardJsonUrl": "",
             "userMap": {}
+        },
+        "autoban": {
+            // Set to true to enable automatic spam detection and banning
+            "enabled": false,
+            // Set to false to actually delete messages and ban users. While true, spam is only detected and logged.
+            "dryRun": true,
+            // Score at which a suspicious message is silently deleted (no ban)
+            "deleteThreshold": 40,
+            // Score at which the user is deleted + banned for banDurationHours
+            "banThreshold": 60,
+            // Duration of the automatic ban in hours
+            "banDurationHours": 24,
+            // ISO8601 duration used as the time window to detect the same message across multiple channels
+            "timeWindowDuration": "PT5M"
         }
     },
 
@@ -94,7 +108,9 @@
         "votesChannelId": "893179191556706384",
         "botSpamChannelId": "893179191556706387",
         "hauptwoisTextChannelId": "893179191825162371",
-        "roleAssignerChannelId": "893179190881452115"
+        "roleAssignerChannelId": "893179190881452115",
+        // Channel ID of a mod-only channel for spam audit logs. Leave empty to disable.
+        "spamLogChannelId": ""
     },
 
     "voiceChannel": {

src/app.ts

@@ -24,6 +24,7 @@ import {
 } from "#/handler/commandHandler.ts";
 import * as guildMemberHandler from "#/handler/guildMemberHandler.ts";
 import deleteThreadMessagesHandler from "#/handler/messageCreate/deleteThreadMessagesHandler.ts";
+import spamDetectionHandler from "#/handler/messageCreate/spamDetectionHandler.ts";
 import { handlePresenceUpdate } from "#/handler/presenceHandler.ts";
 import { createBotContext, type BotContext } from "#/context.ts";
 import { ehreReactionHandler } from "#/commands/ehre.ts";
@@ -135,22 +136,27 @@ login().then(
         client.user.setActivity(config.activity);
 
         try {
+            log.debug("Creating bot context...");
             botContext = await createBotContext(client);
 
+            log.debug("Bot context created, loading commands...");
             await loadCommands(botContext);
 
+            log.debug("Commands loaded, scheduling cron jobs...");
             await cronService.schedule(botContext);
 
             // When the application is ready, slash commands should be registered
+            log.debug("Registering application commands as guild commands...");
             await registerAllApplicationCommandsAsGuildCommands(botContext);
         } catch (err) {
-            sentry.captureException(err);
             log.error(err, "Error in `ready` handler");
+            sentry.captureException(err);
             process.exit(1);
         }
 
         log.info("Registering main event handlers...");
 
+        client.on("messageCreate", m => spamDetectionHandler(m, botContext));
         client.on("messageCreate", m => messageCommandHandler(m, botContext));
         client.on("messageCreate", m => deleteThreadMessagesHandler(m, botContext));
         client.on("guildMemberAdd", m => guildMemberHandler.added(botContext, m));

src/context.ts

@@ -18,6 +18,7 @@ import { SpotifyApi } from "@spotify/web-api-ts-sdk";
 
 import type { UserMapEntry } from "#/commands/aoc.ts";
 import { readConfig } from "#/service/config.ts";
+import log from "#log";
 
 /**
  * Object that's passed to every executed command to make it easier to access common channels without repeatedly retrieving stuff via IDs.
@@ -84,6 +85,14 @@ export interface BotContext {
             leaderBoardJsonUrl: string;
             userMap: Record<Snowflake, UserMapEntry>;
         };
+        autoban: {
+            enabled: boolean;
+            dryRun: boolean;
+            deleteThreshold: number;
+            banThreshold: number;
+            banDurationHours: number;
+            timeWindowDuration: Temporal.Duration;
+        };
     };
 
     roles: {
@@ -120,6 +129,7 @@ export interface BotContext {
         botSpam: TextChannel;
         hauptwoisText: TextChannel;
         roleAssigner: TextChannel;
+        spamLog: TextChannel | null;
     };
 
     voiceChannels: {
@@ -228,8 +238,10 @@ function ensureEmoji(guild: Guild, emojiId: Snowflake, fallbackName: string): Gu
 // #endregion
 
 export async function createBotContext(client: Client<true>): Promise<BotContext> {
+    log.debug("createBotContext: reading config...");
     const config = await readConfig();
 
+    log.debug("createBotContext: config read, resolving guild...");
     const guild = client.guilds.cache.get(config.guildGuildId);
     if (!guild) {
         throw new Error(`Cannot find configured guild "${config.guildGuildId}"`);
@@ -240,7 +252,9 @@ export async function createBotContext(client: Client<true>): Promise<BotContext
     const voiceChannel = config.voiceChannel;
 
     const soundsPath = path.resolve("data/sounds");
+    log.debug({ soundsPath }, "createBotContext: creating sounds directory...");
     await fs.mkdir(soundsPath, { recursive: true });
+    log.debug("createBotContext: sounds directory ready, building context object...");
 
     return {
         client,
@@ -319,6 +333,16 @@ export async function createBotContext(client: Client<true>): Promise<BotContext
                 leaderBoardJsonUrl: config.command.aoc.leaderBoardJsonUrl,
                 userMap: config.command.aoc.userMap,
             },
+            autoban: {
+                enabled: config.command.autoban?.enabled ?? false,
+                dryRun: config.command.autoban?.dryRun ?? true,
+                deleteThreshold: config.command.autoban?.deleteThreshold ?? 40,
+                banThreshold: config.command.autoban?.banThreshold ?? 60,
+                banDurationHours: config.command.autoban?.banDurationHours ?? 24,
+                timeWindowDuration: Temporal.Duration.from(
+                    config.command.autoban?.timeWindowDuration ?? "PT5M",
+                ),
+            },
         },
 
         deleteThreadMessagesInChannelIds: new Set(config.deleteThreadMessagesInChannelIds),
@@ -351,6 +375,9 @@ export async function createBotContext(client: Client<true>): Promise<BotContext
             botSpam: ensureTextChannel(guild, textChannel.botSpamChannelId),
             hauptwoisText: ensureTextChannel(guild, textChannel.hauptwoisTextChannelId),
             roleAssigner: ensureTextChannel(guild, textChannel.roleAssignerChannelId),
+            spamLog: textChannel.spamLogChannelId
+                ? ensureTextChannel(guild, textChannel.spamLogChannelId)
+                : null,
         },
 
         voiceChannels: {