fix: allow forwarded messages with media in media-only channels

application/src/main/java/org/togetherjava/tjbot/features/mediaonly/MediaOnlyChannelListener.java

@@ -13,6 +13,7 @@
 import org.togetherjava.tjbot.features.MessageReceiverAdapter;
 
 import java.awt.Color;
+import java.util.List;
 import java.util.concurrent.TimeUnit;
 import java.util.regex.Pattern;
 
@@ -51,9 +52,39 @@ public void onMessageReceived(MessageReceivedEvent event) {
         }
     }
 
+    /**
+     * Checks whether the given message has no media attached.
+     * <p>
+     * A message is considered to have media if it contains attachments, embeds, or a URL in its
+     * text content. For forwarded messages, the snapshots are also checked for media.
+     *
+     * @param message the message to check
+     * @return {@code true} if the message has no media, {@code false} otherwise
+     */
     private boolean messageHasNoMediaAttached(Message message) {
-        return message.getAttachments().isEmpty() && message.getEmbeds().isEmpty()
-                && !message.getContentRaw().contains("http");
+        if (hasMedia(message.getAttachments(), message.getEmbeds(), message.getContentRaw())) {
+            return false;
+        }
+
+        return message.getMessageSnapshots()
+            .stream()
+            .noneMatch(snapshot -> hasMedia(snapshot.getAttachments(), snapshot.getEmbeds(),
+                    snapshot.getContentRaw()));
+    }
+
+    /**
+     * Checks whether the given content contains any media.
+     * <p>
+     * Media is considered present if there are attachments, embeds, or a URL (identified by
+     * {@code "http"}) in the text content.
+     *
+     * @param attachments the attachments of the message or snapshot
+     * @param embeds the embeds of the message or snapshot
+     * @param content the raw text content of the message or snapshot
+     */
+    private boolean hasMedia(List<Message.Attachment> attachments, List<MessageEmbed> embeds,
+            String content) {
+        return !attachments.isEmpty() || !embeds.isEmpty() || content.contains("http");
     }
 
     private MessageCreateData createNotificationMessage(Message message) {

application/src/test/java/org/togetherjava/tjbot/features/mediaonly/MediaOnlyChannelListenerTest.java

@@ -4,6 +4,7 @@
 import net.dv8tion.jda.api.entities.Message;
 import net.dv8tion.jda.api.entities.MessageEmbed;
 import net.dv8tion.jda.api.entities.channel.ChannelType;
+import net.dv8tion.jda.api.entities.messages.MessageSnapshot;
 import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
 import net.dv8tion.jda.api.utils.messages.MessageCreateBuilder;
 import net.dv8tion.jda.api.utils.messages.MessageCreateData;
@@ -112,4 +113,48 @@ private MessageReceivedEvent sendMessage(MessageCreateData message,
         mediaOnlyChannelListener.onMessageReceived(event);
         return event;
     }
+
+
+    @Test
+    void keepsForwardedMessageWithAttachment() {
+        // GIVEN a forwarded message that contains an attachment inside the snapshot
+        MessageCreateData message = new MessageCreateBuilder().setContent("any").build();
+
+        MessageSnapshot snapshot = mock(MessageSnapshot.class);
+        when(snapshot.getAttachments()).thenReturn(List.of(mock(Message.Attachment.class)));
+        when(snapshot.getEmbeds()).thenReturn(List.of());
+        when(snapshot.getContentRaw()).thenReturn("");
+
+        // WHEN sending the forwarded message
+        MessageReceivedEvent event = sendMessageWithSnapshots(message, List.of(snapshot));
+
+        // THEN it does not get deleted
+        verify(event.getMessage(), never()).delete();
+    }
+
+    @Test
+    void deletesForwardedMessageWithoutMedia() {
+        // GIVEN a forwarded message that contains no media inside the snapshot
+        MessageCreateData message = new MessageCreateBuilder().setContent("any").build();
+
+        MessageSnapshot snapshot = mock(MessageSnapshot.class);
+        when(snapshot.getAttachments()).thenReturn(List.of());
+        when(snapshot.getEmbeds()).thenReturn(List.of());
+        when(snapshot.getContentRaw()).thenReturn("just some text, no media");
+
+        // WHEN sending the forwarded message
+        MessageReceivedEvent event = sendMessageWithSnapshots(message, List.of(snapshot));
+
+        // THEN it gets deleted
+        verify(event.getMessage()).delete();
+    }
+
+    private MessageReceivedEvent sendMessageWithSnapshots(MessageCreateData message,
+            List<MessageSnapshot> snapshots) {
+        MessageReceivedEvent event =
+                jdaTester.createMessageReceiveEvent(message, List.of(), ChannelType.TEXT);
+        when(event.getMessage().getMessageSnapshots()).thenReturn(snapshots);
+        mediaOnlyChannelListener.onMessageReceived(event);
+        return event;
+    }
 }