Fix member leave event listener not being able to find a thread

application/src/main/java/org/togetherjava/tjbot/commands/Features.java

@@ -106,7 +106,7 @@ public static Collection<Feature> createFeatures(JDA jda, Database database, Con
 
         // Event receivers
         features.add(new RejoinModerationRoleListener(actionsStore, config));
-        features.add(new OnGuildLeaveCloseThreadListener(database));
+        features.add(new GuildLeaveCloseThreadListener(config));
         features.add(new LeftoverBookmarksListener(bookmarksSystem));
         features.add(new HelpThreadCreatedListener(helpSystemHelper));
 

application/src/main/java/org/togetherjava/tjbot/commands/help/GuildLeaveCloseThreadListener.java

@@ -0,0 +1,42 @@
+package org.togetherjava.tjbot.commands.help;
+
+import net.dv8tion.jda.api.EmbedBuilder;
+import net.dv8tion.jda.api.entities.MessageEmbed;
+import net.dv8tion.jda.api.events.guild.member.GuildMemberRemoveEvent;
+import net.dv8tion.jda.api.hooks.ListenerAdapter;
+
+import org.togetherjava.tjbot.commands.EventReceiver;
+import org.togetherjava.tjbot.config.Config;
+
+/**
+ * Remove all thread channels associated to a user when they leave the guild.
+ */
+public final class GuildLeaveCloseThreadListener extends ListenerAdapter implements EventReceiver {
+    private final String helpForumPattern;
+
+    /**
+     * Creates a new instance.
+     *
+     * @param config the config to get help forum channel pattern from
+     */
+    public GuildLeaveCloseThreadListener(Config config) {
+        this.helpForumPattern = config.getHelpSystem().getHelpForumPattern();
+    }
+
+    @Override
+    public void onGuildMemberRemove(GuildMemberRemoveEvent event) {
+        MessageEmbed embed = new EmbedBuilder().setTitle("OP left")
+            .setDescription("Closing thread...")
+            .setColor(HelpSystemHelper.AMBIENT_COLOR)
+            .build();
+
+        event.getGuild()
+            .retrieveActiveThreads()
+            .queue(threads -> threads.stream()
+                .filter(thread -> thread.getOwnerIdLong() == event.getUser().getIdLong())
+                .filter(thread -> thread.getParentChannel().getName().matches(helpForumPattern))
+                .forEach(thread -> thread.sendMessageEmbeds(embed)
+                    .flatMap(any -> thread.getManager().setArchived(true))
+                    .queue()));
+    }
+}