Implement Quotes Board

application/config.json.template

@@ -175,5 +175,10 @@
         "fallbackChannelPattern": "java-news-and-changes",
         "pollIntervalInMinutes": 10
     },
+    "coolMessagesConfig": {
+        "minimumReactions": 2,
+        "boardChannelPattern": "quotes",
+        "reactionEmoji": "⭐"
+    },
     "memberCountCategoryPattern": "Info"
 }

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

@@ -48,6 +48,7 @@ public final class Config {
     private final RSSFeedsConfig rssFeedsConfig;
     private final String selectRolesChannelPattern;
     private final String memberCountCategoryPattern;
+    private final QuoteBoardConfig coolMessagesConfig;
 
     @SuppressWarnings("ConstructorWithTooManyParameters")
     @JsonCreator(mode = JsonCreator.Mode.PROPERTIES)
@@ -100,7 +101,9 @@ private Config(@JsonProperty(value = "token", required = true) String token,
                     required = true) FeatureBlacklistConfig featureBlacklistConfig,
             @JsonProperty(value = "rssConfig", required = true) RSSFeedsConfig rssFeedsConfig,
             @JsonProperty(value = "selectRolesChannelPattern",
-                    required = true) String selectRolesChannelPattern) {
+                    required = true) String selectRolesChannelPattern,
+            @JsonProperty(value = "coolMessagesConfig",
+                    required = true) QuoteBoardConfig coolMessagesConfig) {
         this.token = Objects.requireNonNull(token);
         this.githubApiKey = Objects.requireNonNull(githubApiKey);
         this.databasePath = Objects.requireNonNull(databasePath);
@@ -135,6 +138,7 @@ private Config(@JsonProperty(value = "token", required = true) String token,
         this.featureBlacklistConfig = Objects.requireNonNull(featureBlacklistConfig);
         this.rssFeedsConfig = Objects.requireNonNull(rssFeedsConfig);
         this.selectRolesChannelPattern = Objects.requireNonNull(selectRolesChannelPattern);
+        this.coolMessagesConfig = Objects.requireNonNull(coolMessagesConfig);
     }
 
     /**
@@ -428,6 +432,15 @@ public String getSelectRolesChannelPattern() {
         return selectRolesChannelPattern;
     }
 
+    /**
+     * The configuration of the cool messages config.
+     *
+     * @return configuration of cool messages config
+     */
+    public QuoteBoardConfig getCoolMessagesConfig() {
+        return coolMessagesConfig;
+    }
+
     /**
      * Gets the pattern matching the category that is used to display the total member count.
      *

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

@@ -0,0 +1,27 @@
+package org.togetherjava.tjbot.config;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonRootName;
+
+import java.util.Objects;
+
+/**
+ * Configuration for the cool messages board feature, see {@link ``QuoteBoardForwarder``}.
+ */
+@JsonRootName("coolMessagesConfig")
+public record QuoteBoardConfig(
+        @JsonProperty(value = "minimumReactions", required = true) int minimumReactions,
+        @JsonProperty(value = "boardChannelPattern", required = true) String boardChannelPattern,
+        @JsonProperty(value = "reactionEmoji", required = true) String reactionEmoji) {
+
+    /**
+     * Creates a QuoteBoardConfig.
+     *
+     * @param minimumReactions the minimum amount of reactions
+     * @param boardChannelPattern the pattern for the board channel
+     * @param reactionEmoji the emoji with which users should react to
+     */
+    public QuoteBoardConfig {
+        Objects.requireNonNull(boardChannelPattern);
+    }
+}

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

@@ -8,6 +8,7 @@
 import org.togetherjava.tjbot.db.Database;
 import org.togetherjava.tjbot.features.basic.MemberCountDisplayRoutine;
 import org.togetherjava.tjbot.features.basic.PingCommand;
+import org.togetherjava.tjbot.features.basic.QuoteBoardForwarder;
 import org.togetherjava.tjbot.features.basic.RoleSelectCommand;
 import org.togetherjava.tjbot.features.basic.SlashCommandEducator;
 import org.togetherjava.tjbot.features.basic.SuggestionsUpDownVoter;
@@ -154,6 +155,7 @@ public static Collection<Feature> createFeatures(JDA jda, Database database, Con
         features.add(new CodeMessageManualDetection(codeMessageHandler));
         features.add(new SlashCommandEducator());
         features.add(new PinnedNotificationRemover(config));
+        features.add(new QuoteBoardForwarder(config));
 
         // Event receivers
         features.add(new RejoinModerationRoleListener(actionsStore, config));

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

@@ -3,6 +3,7 @@
 import net.dv8tion.jda.api.events.message.MessageDeleteEvent;
 import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
 import net.dv8tion.jda.api.events.message.MessageUpdateEvent;
+import net.dv8tion.jda.api.events.message.react.MessageReactionAddEvent;
 
 import java.util.regex.Pattern;
 
@@ -56,4 +57,13 @@ public interface MessageReceiver extends Feature {
      *        message that was deleted
      */
     void onMessageDeleted(MessageDeleteEvent event);
+
+    /**
+     * Triggered by the core system whenever a new reaction was added to a message in a text channel
+     * of a guild the bot has been added to.
+     *
+     * @param event the event that triggered this, containing information about the corresponding
+     *        reaction that was added
+     */
+    void onMessageReactionAdd(MessageReactionAddEvent event);
 }

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

@@ -3,6 +3,7 @@
 import net.dv8tion.jda.api.events.message.MessageDeleteEvent;
 import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
 import net.dv8tion.jda.api.events.message.MessageUpdateEvent;
+import net.dv8tion.jda.api.events.message.react.MessageReactionAddEvent;
 
 import java.util.regex.Pattern;
 
@@ -57,4 +58,10 @@ public void onMessageUpdated(MessageUpdateEvent event) {
     public void onMessageDeleted(MessageDeleteEvent event) {
         // Adapter does not react by default, subclasses may change this behavior
     }
+
+    @SuppressWarnings("NoopMethodInAbstractClass")
+    @Override
+    public void onMessageReactionAdd(MessageReactionAddEvent event) {
+        // Adapter does not react by default, subclasses may change this behavior
+    }
 }

application/src/main/java/org/togetherjava/tjbot/features/basic/QuoteBoardForwarder.java

@@ -0,0 +1,121 @@
+package org.togetherjava.tjbot.features.basic;
+
+import net.dv8tion.jda.api.JDA;
+import net.dv8tion.jda.api.entities.Message;
+import net.dv8tion.jda.api.entities.MessageReaction;
+import net.dv8tion.jda.api.entities.channel.concrete.TextChannel;
+import net.dv8tion.jda.api.entities.emoji.Emoji;
+import net.dv8tion.jda.api.events.message.react.MessageReactionAddEvent;
+import net.dv8tion.jda.api.requests.RestAction;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import org.togetherjava.tjbot.config.Config;
+import org.togetherjava.tjbot.config.QuoteBoardConfig;
+import org.togetherjava.tjbot.features.MessageReceiverAdapter;
+
+import java.util.Optional;
+import java.util.function.Predicate;
+import java.util.regex.Pattern;
+
+/**
+ * Listens for reaction-add events and turns popular messages into “quotes”.
+ * <p>
+ * When someone reacts to a message with the configured emoji, the listener counts how many users
+ * have used that same emoji. If the total meets or exceeds the minimum threshold and the bot has
+ * not processed the message before, it copies (forwards) the message to the first text channel
+ * whose name matches the configured quote-board pattern, then reacts to the original message itself
+ * to mark it as handled (and to not let people spam react a message and give a way to the bot to
+ * know that a message has been quoted before).
+ * <p>
+ * Key points: - Trigger emoji, minimum vote count and quote-board channel pattern are supplied via
+ * {@code QuoteBoardConfig}.
+ */
+public final class QuoteBoardForwarder extends MessageReceiverAdapter {
+
+    private static final Logger logger = LoggerFactory.getLogger(QuoteBoardForwarder.class);
+    private final Emoji triggerReaction;
+    private final Predicate<String> isQuoteBoardChannelName;
+    private final QuoteBoardConfig config;
+
+    /**
+     * Constructs a new instance of QuoteBoardForwarder.
+     *
+     * @param config the configuration containing settings specific to the cool messages board,
+     *        including the reaction emoji and the pattern to match board channel names
+     */
+    public QuoteBoardForwarder(Config config) {
+        this.config = config.getCoolMessagesConfig();
+        this.triggerReaction = Emoji.fromUnicode(this.config.reactionEmoji());
+
+        isQuoteBoardChannelName =
+                Pattern.compile(this.config.boardChannelPattern()).asMatchPredicate();
+    }
+
+    @Override
+    public void onMessageReactionAdd(MessageReactionAddEvent event) {
+        final MessageReaction messageReaction = event.getReaction();
+        boolean isCoolEmoji = messageReaction.getEmoji().equals(triggerReaction);
+        long guildId = event.getGuild().getIdLong();
+
+        if (hasAlreadyForwardedMessage(event.getJDA(), messageReaction)) {
+            return;
+        }
+
+        final int reactionsCount = (int) messageReaction.retrieveUsers().stream().count();
+        if (isCoolEmoji && reactionsCount >= config.minimumReactions()) {
+            Optional<TextChannel> boardChannel = findQuoteBoardChannel(event.getJDA(), guildId);
+
+            if (boardChannel.isEmpty()) {
+                logger.warn(
+                        "Could not find board channel with pattern '{}' in server with ID '{}'. Skipping reaction handling...",
+                        this.config.boardChannelPattern(), guildId);
+                return;
+            }
+
+            event.retrieveMessage()
+                .queue(message -> markAsProcessed(message).flatMap(v -> message
+                    .forwardTo(boardChannel.orElseThrow())).queue(), e -> logger.warn(
+                            "Unknown error while attempting to retrieve and forward message for quote-board, message is ignored.",
+                            e));
+        }
+    }
+
+    private RestAction<Void> markAsProcessed(Message message) {
+        return message.addReaction(triggerReaction);
+    }
+
+    /**
+     * Gets the board text channel where the quotes go to, wrapped in an optional.
+     *
+     * @param jda the JDA
+     * @param guildId the guild ID
+     * @return the board text channel
+     */
+    private Optional<TextChannel> findQuoteBoardChannel(JDA jda, long guildId) {
+        return jda.getGuildById(guildId)
+            .getTextChannelCache()
+            .stream()
+            .filter(channel -> isQuoteBoardChannelName.test(channel.getName()))
+            .findAny();
+    }
+
+    /**
+     * Inserts a message to the specified text channel
+     *
+     * @return a {@link MessageCreateAction} of the call to make
+     */
+
+    /**
+     * Checks a {@link MessageReaction} to see if the bot has reacted to it.
+     */
+    private boolean hasAlreadyForwardedMessage(JDA jda, MessageReaction messageReaction) {
+        if (!triggerReaction.equals(messageReaction.getEmoji())) {
+            return false;
+        }
+
+        return messageReaction.retrieveUsers()
+            .parallelStream()
+            .anyMatch(user -> jda.getSelfUser().getIdLong() == user.getIdLong());
+    }
+}

application/src/main/java/org/togetherjava/tjbot/features/system/BotCore.java

@@ -13,6 +13,7 @@
 import net.dv8tion.jda.api.events.message.MessageDeleteEvent;
 import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
 import net.dv8tion.jda.api.events.message.MessageUpdateEvent;
+import net.dv8tion.jda.api.events.message.react.MessageReactionAddEvent;
 import net.dv8tion.jda.api.hooks.ListenerAdapter;
 import net.dv8tion.jda.api.interactions.callbacks.IReplyCallback;
 import net.dv8tion.jda.api.interactions.components.ComponentInteraction;
@@ -238,6 +239,14 @@ public void onMessageDelete(final MessageDeleteEvent event) {
         }
     }
 
+    @Override
+    public void onMessageReactionAdd(final MessageReactionAddEvent event) {
+        if (event.isFromGuild()) {
+            getMessageReceiversSubscribedTo(event.getChannel())
+                .forEach(messageReceiver -> messageReceiver.onMessageReactionAdd(event));
+        }
+    }
+
     private Stream<MessageReceiver> getMessageReceiversSubscribedTo(Channel channel) {
         String channelName = channel.getName();
         return channelNameToMessageReceiver.entrySet()