feat(discord): download attachments from forwarded messages (#17049)

Co-authored-by: Shadow <shadow@openclaw.ai>

src/discord/monitor/message-utils.ts

@@ -156,6 +156,46 @@ export async function resolveMediaList(
   return out;
 }
 
+export async function resolveForwardedMediaList(
+  message: Message,
+  maxBytes: number,
+): Promise<DiscordMediaInfo[]> {
+  const snapshots = resolveDiscordMessageSnapshots(message);
+  if (snapshots.length === 0) {
+    return [];
+  }
+  const out: DiscordMediaInfo[] = [];
+  for (const snapshot of snapshots) {
+    const attachments = snapshot.message?.attachments;
+    if (!attachments || attachments.length === 0) {
+      continue;
+    }
+    for (const attachment of attachments) {
+      try {
+        const fetched = await fetchRemoteMedia({
+          url: attachment.url,
+          filePathHint: attachment.filename ?? attachment.url,
+        });
+        const saved = await saveMediaBuffer(
+          fetched.buffer,
+          fetched.contentType ?? attachment.content_type,
+          "inbound",
+          maxBytes,
+        );
+        out.push({
+          path: saved.path,
+          contentType: saved.contentType,
+          placeholder: inferPlaceholder(attachment),
+        });
+      } catch (err) {
+        const id = attachment.id ?? attachment.url;
+        logVerbose(`discord: failed to download forwarded attachment ${id}: ${String(err)}`);
+      }
+    }
+  }
+  return out;
+}
+
 function inferPlaceholder(attachment: APIAttachment): string {
   const mime = attachment.content_type ?? "";
   if (mime.startsWith("image/")) {