replace f*cks with hugs

build.gradle.kts

@@ -37,6 +37,9 @@ dependencies {
 
     // Quartz scheduler
     implementation("org.quartz-scheduler:quartz:2.3.2")
+
+    // Webhooks
+    implementation("club.minnced:discord-webhooks:0.8.0")
 
     // Lombok Annotations
     compileOnly("org.projectlombok:lombok:1.18.24")

src/main/java/net/javadiscord/javabot/Bot.java

@@ -142,7 +142,8 @@ private static void addEventListeners(JDA jda) {
 				new HelpChannelListener(),
 				new ShareKnowledgeVoteListener(),
 				new JobChannelVoteListener(),
-				new PingableNameListener()
+				new PingableNameListener(),
+				new HugListener()
 		);
 	}
 }

src/main/java/net/javadiscord/javabot/listener/HugListener.java

@@ -0,0 +1,76 @@
+package net.javadiscord.javabot.listener;
+
+import javax.annotation.Nonnull;
+
+import lombok.extern.slf4j.Slf4j;
+import net.dv8tion.jda.api.entities.ChannelType;
+import net.dv8tion.jda.api.entities.GuildMessageChannel;
+import net.dv8tion.jda.api.entities.Message;
+import net.dv8tion.jda.api.entities.TextChannel;
+import net.dv8tion.jda.api.entities.Webhook;
+import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
+import net.dv8tion.jda.api.hooks.ListenerAdapter;
+import net.javadiscord.javabot.Bot;
+import net.javadiscord.javabot.util.WebhookUtil;
+
+/**
+ * Replaces all occurences of 'fuck' in incoming messages with 'hug'.
+ */
+@Slf4j
+public class HugListener extends ListenerAdapter {
+	@Override
+	public void onMessageReceived(@Nonnull MessageReceivedEvent event) {
+		if (!event.isFromGuild()) {
+			return;
+		}
+		if (Bot.autoMod.hasSuspiciousLink(event.getMessage()) || Bot.autoMod.hasAdvertisingLink(event.getMessage())) {
+			return;
+		}
+		if (!event.getMessage().getMentions().getUsers().isEmpty()) {
+			return;
+		}
+		if (event.isWebhookMessage()) {
+			return;
+		}
+		TextChannel tc = null;
+		if (event.isFromType(ChannelType.TEXT)) {
+			tc = event.getTextChannel();
+		}
+		if (event.isFromThread()) {
+			GuildMessageChannel parentChannel = event.getThreadChannel().getParentMessageChannel();
+			if (parentChannel instanceof TextChannel textChannel) {
+				tc = textChannel;
+			}
+		}
+		if (tc == null) {
+			return;
+		}
+		final TextChannel textChannel = tc;
+		String content = event.getMessage().getContentRaw();
+		String lowerCaseContent = content.toLowerCase();
+		if (lowerCaseContent.contains("fuck")) {
+			long threadId = event.isFromThread() ? event.getThreadChannel().getIdLong() : 0;
+			StringBuilder sb = new StringBuilder(content.length());
+			int index = 0;
+			int indexBkp = index;
+			while ((index = lowerCaseContent.indexOf("fuck", index)) != -1) {
+				sb.append(content.substring(indexBkp, index));
+				sb.append("hug");
+				indexBkp = index++ + 4;
+			}
+
+			sb.append(content.substring(indexBkp, content.length()));
+			WebhookUtil.ensureWebhookExists(textChannel,
+					wh -> sendWebhookMessage(wh, event.getMessage(), sb.toString(), threadId),
+					e -> log.error("Webhook lookup/creation failed", e));
+		}
+	}
+
+	private void sendWebhookMessage(Webhook webhook, Message originalMessage, String newMessageContent, long threadId) {
+		WebhookUtil.mirrorMessageToWebhook(webhook, originalMessage, newMessageContent, threadId)
+				.thenAccept(unused -> originalMessage.delete().queue()).exceptionally(e -> {
+					log.error("replacing the content 'fuck' with 'hug' in an incoming message failed", e);
+					return null;
+				});
+	}
+}

src/main/java/net/javadiscord/javabot/util/WebhookUtil.java

@@ -0,0 +1,93 @@
+package net.javadiscord.javabot.util;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Consumer;
+
+import club.minnced.discord.webhook.WebhookClientBuilder;
+import club.minnced.discord.webhook.external.JDAWebhookClient;
+import club.minnced.discord.webhook.send.AllowedMentions;
+import club.minnced.discord.webhook.send.WebhookMessageBuilder;
+import net.dv8tion.jda.api.entities.Message;
+import net.dv8tion.jda.api.entities.TextChannel;
+import net.dv8tion.jda.api.entities.Webhook;
+import net.dv8tion.jda.api.entities.Message.Attachment;
+
+/**
+ * Contains utility methods for dealing with Discord Webhooks.
+ */
+public class WebhookUtil {
+	private WebhookUtil() {
+	}
+
+	/**
+	 * Makes sure that a writable webhook exists in a specific channel. if no
+	 * suitable webhook is found, one is created.
+	 * 
+	 * @param channel the {@link TextChannel} the webhook should exist in
+	 * @param callback an action that is executed once a webhook is
+	 * found/created
+	 */
+	public static void ensureWebhookExists(TextChannel channel, Consumer<? super Webhook> callback) {
+		ensureWebhookExists(channel, callback, err -> {
+		});
+	}
+
+	/**
+	 * Makes sure that a writable webhook exists in a specific channel. if no
+	 * suitable webhook is found, one is created.
+	 * 
+	 * @param channel the {@link TextChannel} the webhook should exist in
+	 * @param callback an action that is executed once a webhook is
+	 * found/created
+	 * @param failureCallback an action that is executed if the webhook
+	 * lookup/creation failed
+	 */
+	public static void ensureWebhookExists(TextChannel channel, Consumer<? super Webhook> callback,
+			Consumer<? super Throwable> failureCallback) {
+
+		channel.retrieveWebhooks().queue(webhooks -> {
+			Optional<Webhook> hook = webhooks.stream()
+					.filter(webhook -> webhook.getChannel().getIdLong() == channel.getIdLong())
+					.filter(wh -> wh.getToken() != null).findAny();
+			if (hook.isPresent()) {
+				callback.accept(hook.get());
+			} else {
+				channel.createWebhook("JavaBot-webhook").queue(callback, failureCallback);
+			}
+		}, failureCallback);
+	}
+
+	/**
+	 * Resends a specific message using a webhook with a custom content.
+	 * 
+	 * @param webhook the webhook used for sending the message
+	 * @param originalMessage the message to copy
+	 * @param newMessageContent the new (custom) content
+	 * @param threadId the thread to send the message in or {@code 0} if the
+	 * message should be sent directly
+	 * @return a {@link CompletableFuture} representing the action of sending
+	 * the message
+	 */
+	public static CompletableFuture<Void> mirrorMessageToWebhook(Webhook webhook, Message originalMessage,
+			String newMessageContent, long threadId) {
+		JDAWebhookClient client = new WebhookClientBuilder(webhook.getIdLong(), webhook.getToken())
+				.setThreadId(threadId).buildJDA();
+		WebhookMessageBuilder message = new WebhookMessageBuilder().setContent(newMessageContent)
+				.setAllowedMentions(AllowedMentions.none())
+				.setAvatarUrl(originalMessage.getMember().getEffectiveAvatarUrl())
+				.setUsername(originalMessage.getMember().getEffectiveName());
+
+		List<Attachment> attachments = originalMessage.getAttachments();
+		@SuppressWarnings("unchecked")
+		CompletableFuture<?>[] futures = new CompletableFuture<?>[attachments.size()];
+		for (int i = 0; i < attachments.size(); i++) {
+			Attachment attachment = attachments.get(i);
+			futures[i] = attachment.getProxy().download().thenAccept(
+					is -> message.addFile((attachment.isSpoiler() ? "SPOILER_" : "") + attachment.getFileName(), is));
+		}
+		return CompletableFuture.allOf(futures).thenAccept(unused -> client.send(message.build()))
+				.whenComplete((result, err) -> client.close());
+	}
+}