export const prerender = false;

import type { APIRoute } from 'astro';
import { ImapFlow } from 'imapflow';
import { simpleParser } from 'mailparser';
import { getAccount } from '../../../lib/mail-accounts';

export const GET: APIRoute = async ({ url }) => {
  const id = url.searchParams.get('account');
  const uid = url.searchParams.get('uid');
  const index = parseInt(url.searchParams.get('index') || '0');
  const folder = url.searchParams.get('folder') || 'INBOX';

  const acct = id ? getAccount(id) : undefined;
  if (!acct || !uid) return json({ error: 'Bad request' }, 400);

  const client = new ImapFlow({
    host: acct.imap.host, port: acct.imap.port, secure: true,
    auth: { user: acct.imap.user, pass: acct.imap.password },
    logger: false,
  });

  try {
    await client.connect();
    const lock = await client.getMailboxLock(folder);
    try {
      const msg = await client.fetchOne(uid, { source: true }, { uid: true });
      if (!msg?.source) return json({ error: 'Message not found' }, 404);

      const parsed = await simpleParser(msg.source);
      const att = parsed.attachments?.[index];
      if (!att) return json({ error: 'Attachment not found' }, 404);

      return new Response(att.content, {
        headers: {
          'Content-Type': att.contentType || 'application/octet-stream',
          'Content-Disposition': `attachment; filename*=UTF-8''${encodeURIComponent(att.filename || 'download')}`,
          'Content-Length': String(att.content.length),
        },
      });
    } finally {
      lock.release();
    }
  } catch (e: any) {
    return json({ error: e.message }, 500);
  } finally {
    await client.logout().catch(() => {});
  }
};

function json(data: object, status = 200) {
  return new Response(JSON.stringify(data), { status, headers: { 'Content-Type': 'application/json' } });
}