import type { NextApiRequest, NextApiResponse } from 'next';
import Cookies from 'cookies';

export default async function handler(req: NextApiRequest, res: NextApiResponse) {
  if (req.method !== 'GET') {
    return res.status(405).json({ message: 'Method not allowed' });
  }

  const { id } = req.query;
  if (!id || typeof id !== 'string') {
    return res.status(400).json({ message: 'Missing or invalid file ID' });
  }

  const cookies = new Cookies(req)
  const token = cookies.get('token');

  const userAgent = req.headers['user-agent'] || '';
  const clientIp =
    (req.headers['x-forwarded-for'] as string)?.split(',')[0] ||
    req.socket.remoteAddress ||
    '';

  try {
    const apiUrl = `${process.env.API_GATEWAY}/attachment/stream/${encodeURIComponent(id)}`;

    const response = await fetch(apiUrl, {
      headers: {
        Authorization: `Bearer ${token}`,
        'X-Client-IP': clientIp === '::1' ? '127.0.0.1' : clientIp,
        'User-Agent': userAgent,
      },
    });

    if (!response.ok || !response.body) {
      return res.status(response.status).json({ message: 'Error fetching file' });
    }

    // Forward headers
    res.setHeader(
      'Content-Disposition',
      response.headers.get('content-disposition') || `attachment; filename="${id}"`
    );
    res.setHeader(
      'Content-Type',
      response.headers.get('content-type') || 'application/octet-stream'
    );

    // Pipe fetch response to Next.js response
    const reader = response.body.getReader();

    const stream = new ReadableStream({
      async pull(controller) {
        const { done, value } = await reader.read();
        if (done) {
          controller.close();
        } else {
          controller.enqueue(value);
        }
      },
    });

    const streamResponse = new Response(stream);
    const body = streamResponse.body;

    if (body) {
      body.pipeTo(new WritableStream({
        write(chunk) {
          res.write(Buffer.from(chunk));
        },
        close() {
          res.end();
        },
      }));
    }
  } catch (err: any) {
    console.error('Download error:', err?.message || err);
    res.status(500).json({ message: 'Error downloading file' });
  }
}