Automatically pin first message in projects forum

application/config.json.template

@@ -6,6 +6,7 @@
     "discordGuildInvite": "https://discord.com/invite/XXFUXzK",
     "modAuditLogChannelPattern": "mod-audit-log",
     "modMailChannelPattern": "modmail",
+    "projectsChannelPattern": "projects"
     "mutedRolePattern": "Muted",
     "heavyModerationRolePattern": "Moderator",
     "softModerationRolePattern": "Moderator|Community Ambassador",

application/src/main/java/org/togetherjava/tjbot/config/Config.java

@@ -23,6 +23,7 @@ public final class Config {
     private final String discordGuildInvite;
     private final String modAuditLogChannelPattern;
     private final String modMailChannelPattern;
+    private final String projectsChannelPattern;
     private final String mutedRolePattern;
     private final String heavyModerationRolePattern;
     private final String softModerationRolePattern;
@@ -58,6 +59,8 @@ private Config(@JsonProperty(value = "token", required = true) String token,
                     required = true) String modAuditLogChannelPattern,
             @JsonProperty(value = "modMailChannelPattern",
                     required = true) String modMailChannelPattern,
+            @JsonProperty(value = "projectsChannelPattern",
+                    required = true) String projectsChannelPattern,
             @JsonProperty(value = "mutedRolePattern", required = true) String mutedRolePattern,
             @JsonProperty(value = "heavyModerationRolePattern",
                     required = true) String heavyModerationRolePattern,
@@ -103,6 +106,7 @@ private Config(@JsonProperty(value = "token", required = true) String token,
         this.discordGuildInvite = Objects.requireNonNull(discordGuildInvite);
         this.modAuditLogChannelPattern = Objects.requireNonNull(modAuditLogChannelPattern);
         this.modMailChannelPattern = Objects.requireNonNull(modMailChannelPattern);
+        this.projectsChannelPattern = Objects.requireNonNull(projectsChannelPattern);
         this.mutedRolePattern = Objects.requireNonNull(mutedRolePattern);
         this.heavyModerationRolePattern = Objects.requireNonNull(heavyModerationRolePattern);
         this.softModerationRolePattern = Objects.requireNonNull(softModerationRolePattern);
@@ -170,6 +174,16 @@ public String getModMailChannelPattern() {
         return modMailChannelPattern;
     }
 
+    /**
+     * Gets the REGEX pattern used to identify the channel that is supposed to contain information
+     * about user projects
+     *
+     * @return the channel name pattern
+     */
+    public String getProjectsChannelPattern() {
+        return projectsChannelPattern;
+    }
+
     /**
      * Gets the token of the Discord bot to connect this application to.
      *

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

@@ -62,6 +62,7 @@
 import org.togetherjava.tjbot.features.moderation.scam.ScamHistoryPurgeRoutine;
 import org.togetherjava.tjbot.features.moderation.scam.ScamHistoryStore;
 import org.togetherjava.tjbot.features.moderation.temp.TemporaryModerationRoutine;
+import org.togetherjava.tjbot.features.projects.ProjectsThreadCreatedListener;
 import org.togetherjava.tjbot.features.reminder.RemindRoutine;
 import org.togetherjava.tjbot.features.reminder.ReminderCommand;
 import org.togetherjava.tjbot.features.system.BotCore;
@@ -157,6 +158,7 @@ public static Collection<Feature> createFeatures(JDA jda, Database database, Con
         features.add(new LeftoverBookmarksListener(bookmarksSystem));
         features.add(new HelpThreadCreatedListener(helpSystemHelper));
         features.add(new HelpThreadLifecycleListener(helpSystemHelper, database));
+        features.add(new ProjectsThreadCreatedListener(config));
 
         // Message context commands
         features.add(new TransferQuestionCommand(config, chatGptService));

application/src/main/java/org/togetherjava/tjbot/features/projects/ProjectsThreadCreatedListener.java

@@ -0,0 +1,60 @@
+package org.togetherjava.tjbot.features.projects;
+
+import com.github.benmanes.caffeine.cache.Cache;
+import com.github.benmanes.caffeine.cache.Caffeine;
+import net.dv8tion.jda.api.entities.channel.Channel;
+import net.dv8tion.jda.api.entities.channel.concrete.ThreadChannel;
+import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
+import net.dv8tion.jda.api.hooks.ListenerAdapter;
+
+import org.togetherjava.tjbot.config.Config;
+import org.togetherjava.tjbot.features.EventReceiver;
+
+import java.time.Instant;
+import java.time.temporal.ChronoUnit;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Listens for new threads being created in the "projects" forum and pins the first message. *
+ * {@link Config#getProjectsChannelPattern()}.
+ */
+public final class ProjectsThreadCreatedListener extends ListenerAdapter implements EventReceiver {
+    private final String configProjectsChannelPattern;
+    private final Cache<Long, Instant> threadIdToCreatedAtCache = Caffeine.newBuilder()
+        .maximumSize(1_000)
+        .expireAfterAccess(2, TimeUnit.of(ChronoUnit.MINUTES))
+        .build();
+
+    public ProjectsThreadCreatedListener(Config config) {
+        configProjectsChannelPattern = config.getProjectsChannelPattern();
+    }
+
+    @Override
+    public void onMessageReceived(MessageReceivedEvent event) {
+        if (event.isFromThread()) {
+            ThreadChannel threadChannel = event.getChannel().asThreadChannel();
+            Channel parentChannel = threadChannel.getParentChannel();
+            boolean isPost = isPostMessage(threadChannel);
+
+            if (parentChannel.getName().equals(configProjectsChannelPattern) && isPost) {
+                handleProjectThread(event);
+            }
+        }
+    }
+
+    private boolean wasThreadAlreadyHandled(long threadChannelId) {
+        Instant now = Instant.now();
+        Instant createdAt = threadIdToCreatedAtCache.get(threadChannelId, any -> now);
+        return createdAt != now;
+    }
+
+    private boolean isPostMessage(ThreadChannel threadChannel) {
+        int messageCount = threadChannel.getMessageCount();
+        return messageCount <= 1 && !wasThreadAlreadyHandled(threadChannel.getIdLong());
+    }
+
+    private void handleProjectThread(MessageReceivedEvent event) {
+        // Pin the first message in the thread
+        event.getMessage().pin().queue();
+    }
+}

application/src/main/java/org/togetherjava/tjbot/features/projects/package-info.java

@@ -0,0 +1,11 @@
+/**
+ * This packages offers all the functionality for the projects channel. The core class is
+ * {@link org.togetherjava.tjbot.features.projects.ProjectsThreadCreatedListener}.
+ */
+@MethodsReturnNonnullByDefault
+@ParametersAreNonnullByDefault
+package org.togetherjava.tjbot.features.projects;
+
+import org.togetherjava.tjbot.annotations.MethodsReturnNonnullByDefault;
+
+import javax.annotation.ParametersAreNonnullByDefault;