Add file preview

Uses https://discordbot.matyrobbrt.com/fpreview

Author: Matyrobbrt

src/commander/java/com/mcmoddev/mmdbot/commander/TheCommander.java

@@ -47,6 +47,7 @@
 import com.mcmoddev.mmdbot.commander.docs.ConfigBasedElementLoader;
 import com.mcmoddev.mmdbot.commander.docs.DocsCommand;
 import com.mcmoddev.mmdbot.commander.docs.NormalDocsSender;
+import com.mcmoddev.mmdbot.commander.eventlistener.FilePreviewListener;
 import com.mcmoddev.mmdbot.commander.eventlistener.ReferencingListener;
 import com.mcmoddev.mmdbot.commander.eventlistener.ThreadListener;
 import com.mcmoddev.mmdbot.commander.migrate.QuotesMigrator;
@@ -442,7 +443,7 @@ record SlashCommandRegistration(Object fieldValue, RegisterSlashCommand annotati
         }
 
         EventListeners.MISC_LISTENER.addListeners(new ThreadListener(),
-            new ThreadChannelCreatorEvents(this::getGeneralConfig));
+            new ThreadChannelCreatorEvents(this::getGeneralConfig), new FilePreviewListener());
 
         COLLECT_TASKS_LISTENER.register(Events.MISC_BUS);
         CurseForgeCommand.RG_TASK_SCHEDULER_LISTENER.register(Events.MISC_BUS);

src/commander/java/com/mcmoddev/mmdbot/commander/eventlistener/FilePreviewListener.java

@@ -0,0 +1,107 @@
+/*
+ * MMDBot - https://github.com/MinecraftModDevelopment/MMDBot
+ * Copyright (C) 2016-2022 <MMD - MinecraftModDevelopment>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * Specifically version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
+ * USA
+ * https://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
+ */
+package com.mcmoddev.mmdbot.commander.eventlistener;
+
+import net.dv8tion.jda.api.MessageBuilder;
+import net.dv8tion.jda.api.events.GenericEvent;
+import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
+import net.dv8tion.jda.api.hooks.EventListener;
+import net.dv8tion.jda.api.interactions.components.ActionRow;
+import net.dv8tion.jda.api.interactions.components.Component;
+import net.dv8tion.jda.api.interactions.components.buttons.Button;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class FilePreviewListener implements EventListener {
+    public FilePreviewListener() {}
+
+    public static final List<String> BLACKLISTED_EXTENSIONS = List.of(
+        "png", "jpeg", "jpg", "jpe", "jif", "jfif", "jfi", "jp2",
+        "tiff", "tif", "mp4", "avi", "mp3", "wav", "gif", "webp", "psd", "bpm"
+    );
+
+    public static final String URL = "https://discordbot.matyrobbrt.com/fpreview?url=";
+
+    @Override
+    public void onEvent(@NotNull final GenericEvent gE) {
+        if (!(gE instanceof MessageReceivedEvent event)) return;
+        final var attachments = event.getMessage().getAttachments();
+        if (attachments.isEmpty()) return;
+        final var messageBuilder = new MessageBuilder()
+            .append("Paste version of ");
+        final var rows = new ArrayList<List<Button>>();
+        for (var i = 0; i < attachments.size(); i++) {
+            final var attach = attachments.get(i);
+            if (!BLACKLISTED_EXTENSIONS.contains(attach.getFileExtension())) {
+                final var url = URL + attach.getUrl();
+                messageBuilder
+                    .append('`')
+                    .append(attach.getFileName())
+                    .append('`');
+
+                if (i != attachments.size() - 1) {
+                    messageBuilder.append(", ");
+                } else {
+                    messageBuilder.append(' ');
+                }
+                addButton(rows, Button.link(url, trimIfTooLong("View " + attach.getFileName())));
+            }
+        }
+        if (!rows.isEmpty()) {
+            messageBuilder.append("from ")
+                .append(event.getAuthor().getAsMention());
+            event.getMessage().reply(messageBuilder.build())
+                .setActionRows(rows.stream().map(ActionRow::of).toList())
+                .mentionRepliedUser(false)
+                .allowedMentions(List.of())
+                .queue();
+        }
+    }
+
+    private static String trimIfTooLong(String str) {
+        if (str.length() > Button.LABEL_MAX_LENGTH - 3) {
+            return str.substring(0, Button.LABEL_MAX_LENGTH - 3) + "...";
+        } else {
+            return str;
+        }
+    }
+
+    private static void addButton(List<List<Button>> list, Button button) {
+        if (list.isEmpty()) {
+            final var nL = new ArrayList<Button>();
+            nL.add(button);
+            list.add(nL);
+        } else {
+            final var lastList = list.get(list.size() - 1);
+            if (lastList.size() >= Component.Type.BUTTON.getMaxPerRow()) {
+                final var newList = new ArrayList<Button>();
+                newList.add(button);
+                if (list.size() < 5) {
+                    list.add(newList);
+                }
+            } else {
+                lastList.add(button);
+            }
+        }
+    }
+}