import crypto from 'node:crypto';

export const DOCX_MIME_TYPE = 'application/vnd.openxmlformats-officedocument.wordprocessingml.document';

export async function registerChatDocxArtifactForConversation({
  registry,
  user,
  bundle,
  requestBody = {},
  filename,
  buffer,
  now = Date.now(),
}) {
  if (!registry || !user?.id || !filename || !Buffer.isBuffer(buffer)) return null;
  const sessionId = String(requestBody.session_id ?? requestBody.sessionId ?? '').trim();
  const messageId = String(requestBody.message_id ?? requestBody.messageId ?? '').trim();
  if (!sessionId || !messageId) return null;
  const selectedLinkIndex = Number(requestBody.selected_link_index ?? requestBody.selectedLinkIndex ?? 0);
  const hash = crypto
    .createHash('sha256')
    .update(`${user.id}:${sessionId}:${messageId}:${selectedLinkIndex}:${filename}`)
    .digest('hex')
    .slice(0, 16);
  const artifactId = `ca_docx_${hash}`;
  const relativePath = `artifacts/${artifactId}/${filename}`;
  const { packageRecord, writeResult } = await registry.putObjectForSession({
    userId: user.id,
    sessionId,
    title: bundle?.source?.session?.name ?? null,
    relativePath,
    body: buffer,
  });
  const canonicalUrl =
    `/api/mindspace/v1/conversation-packages/${encodeURIComponent(sessionId)}` +
    `/artifacts/${encodeURIComponent(artifactId)}/download`;
  const artifact = await registry.recordArtifact({
    id: artifactId,
    packageId: packageRecord.id,
    artifactKind: 'docx',
    messageId,
    displayName: filename,
    mimeType: DOCX_MIME_TYPE,
    sizeBytes: buffer.length,
    storageKey: writeResult.key,
    canonicalUrl,
    sortOrder: now,
    now,
  });
  await registry.writeManifestForSession({
    userId: user.id,
    sessionId,
  });
  return artifact;
}