Feature: Implement /rewrite command for message improvement using Cha…

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

@@ -41,6 +41,7 @@
 import org.togetherjava.tjbot.features.mathcommands.wolframalpha.WolframAlphaCommand;
 import org.togetherjava.tjbot.features.mediaonly.MediaOnlyChannelListener;
 import org.togetherjava.tjbot.features.messages.MessageCommand;
+import org.togetherjava.tjbot.features.messages.RewriteMsgCommand;
 import org.togetherjava.tjbot.features.moderation.BanCommand;
 import org.togetherjava.tjbot.features.moderation.KickCommand;
 import org.togetherjava.tjbot.features.moderation.ModerationActionsStore;
@@ -207,6 +208,7 @@ public static Collection<Feature> createFeatures(JDA jda, Database database, Con
         features.add(new ChatGptCommand(chatGptService, helpSystemHelper));
         features.add(new JShellCommand(jshellEval));
         features.add(new MessageCommand());
+        features.add(new RewriteMsgCommand(chatGptService));
 
         FeatureBlacklist<Class<?>> blacklist = blacklistConfig.normal();
         return blacklist.filterStream(features.stream(), Object::getClass).toList();

application/src/main/java/org/togetherjava/tjbot/features/messages/RewriteMsgCommand.java

@@ -0,0 +1,153 @@
+package org.togetherjava.tjbot.features.messages;
+
+import net.dv8tion.jda.api.events.interaction.command.SlashCommandInteractionEvent;
+import net.dv8tion.jda.api.interactions.commands.OptionMapping;
+import net.dv8tion.jda.api.interactions.commands.OptionType;
+import net.dv8tion.jda.api.interactions.commands.build.OptionData;
+import org.jetbrains.annotations.Nullable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import org.togetherjava.tjbot.features.CommandVisibility;
+import org.togetherjava.tjbot.features.SlashCommandAdapter;
+import org.togetherjava.tjbot.features.chatgpt.ChatGptModel;
+import org.togetherjava.tjbot.features.chatgpt.ChatGptService;
+
+import java.util.Arrays;
+import java.util.Objects;
+import java.util.Optional;
+
+/**
+ * The implemented command is {@code /rewrite-msg}, which allows users to have their message
+ * rewritten in a clearer, more professional, or better structured form using ChatGPT AI.
+ * <p>
+ * The rewritten message is shown as an ephemeral message visible only to the user who triggered the
+ * command, making it perfect for getting quick writing improvements without cluttering the channel.
+ * <p>
+ * Users can optionally specify a tone/style for the rewrite. If not provided, defaults to CLEAR.
+ */
+public final class RewriteMsgCommand extends SlashCommandAdapter {
+    private static final Logger logger = LoggerFactory.getLogger(RewriteMsgCommand.class);
+    public static final String COMMAND_NAME = "rewrite-msg";
+    private static final String MESSAGE_OPTION = "message";
+    private static final String TONE_OPTION = "tone";
+    private static final int MAX_MESSAGE_LENGTH = 500;
+    private static final int MIN_MESSAGE_LENGTH = 3;
+    private static final ChatGptModel CHAT_GPT_MODEL = ChatGptModel.HIGH_QUALITY;
+
+    private final ChatGptService chatGptService;
+
+    private static String buildResponse(String userMessage, String rewrittenMessage, MsgTone tone) {
+        final String toneLabel = tone.displayName;
+
+        return """
+                **Rewritten message (%s)**
+
+                **Original:**
+                %s
+
+                **Rewritten:**
+                %s""".formatted(toneLabel, userMessage, rewrittenMessage);
+    }
+
+    private static String buildChatGptPrompt(String userMessage, MsgTone tone) {
+        return """
+                Please rewrite the following message to make it clearer, more professional, \
+                and better structured. Maintain the original meaning while improving the quality \
+                of the writing. Do NOT use em-dashes (—). %s
+
+                If the message is already well-written, provide minor improvements.
+
+                Original message:
+                %s""".formatted(tone.description, userMessage);
+    }
+
+    /**
+     * Creates the slash command definition and configures available options for rewriting messages.
+     *
+     * @param chatGptService service for interacting with ChatGPT
+     */
+    public RewriteMsgCommand(ChatGptService chatGptService) {
+        super(COMMAND_NAME, "Let AI rephrase and improve your message", CommandVisibility.GUILD);
+
+        this.chatGptService = chatGptService;
+
+        final OptionData messageOption =
+                new OptionData(OptionType.STRING, MESSAGE_OPTION, "The message you want to rewrite",
+                        true)
+                    .setMinLength(MIN_MESSAGE_LENGTH)
+                    .setMaxLength(MAX_MESSAGE_LENGTH);
+
+        final OptionData toneOption = new OptionData(OptionType.STRING, TONE_OPTION,
+                "The tone/style for the rewritten message (default: " + MsgTone.CLEAR.displayName
+                        + ")",
+                false);
+
+        Arrays.stream(MsgTone.values())
+            .forEach(tone -> toneOption.addChoice(tone.displayName, tone.name()));
+
+        getData().addOptions(messageOption, toneOption);
+    }
+
+    @Override
+    public void onSlashCommand(SlashCommandInteractionEvent event) {
+        final String userMessage =
+                Objects.requireNonNull(event.getOption(MESSAGE_OPTION)).getAsString();
+
+        final MsgTone tone = parseTone(event.getOption(TONE_OPTION), event.getUser().getId());
+
+        event.deferReply(true).queue();
+
+        final Optional<String> rewrittenMessage = this.rewrite(userMessage, tone);
+
+        if (rewrittenMessage.isEmpty()) {
+            logger.debug("Failed to obtain a response for /rewrite-msg, original message: '{}'",
+                    userMessage);
+            event.getHook()
+                .editOriginal(
+                        "An error occurred while processing your request. Please try again later.")
+                .queue();
+            return;
+        }
+
+        final String response = buildResponse(userMessage, rewrittenMessage.orElseThrow(), tone);
+
+        event.getHook().editOriginal(response).queue();
+    }
+
+    private MsgTone parseTone(@Nullable OptionMapping toneOption, String userId)
+            throws IllegalArgumentException {
+        if (toneOption == null) {
+            logger.debug("Tone option not provided for user: {}, using default CLEAR", userId);
+            return MsgTone.CLEAR;
+        }
+
+        final String toneValue = toneOption.getAsString();
+        final MsgTone tone = MsgTone.valueOf(toneValue);
+
+        logger.debug("Parsed tone '{}' for user: {}", tone.displayName, userId);
+
+        return tone;
+    }
+
+    private Optional<String> rewrite(String userMessage, MsgTone tone) {
+        final String rewritePrompt = buildChatGptPrompt(userMessage, tone);
+
+        return chatGptService.ask(rewritePrompt, tone.displayName, CHAT_GPT_MODEL);
+    }
+
+    private enum MsgTone {
+        CLEAR("Clear", "Make it clear and easy to understand."),
+        PRO("Pro", "Use a professional and polished tone."),
+        DETAILED("Detailed", "Expand with more detail and explanation."),
+        TECHNICAL("Technical", "Use technical and specialized language where appropriate.");
+
+        private final String displayName;
+        private final String description;
+
+        MsgTone(String displayName, String description) {
+            this.displayName = displayName;
+            this.description = description;
+        }
+    }
+}