import type { VercelRequest, VercelResponse } from '@vercel/node';

const TRAFFIC_DROPBOX_URL = "https://www.dropbox.com/scl/fi/9cenju8djxav9z6q5if6m/Traffic-Weekly.xlsx?rlkey=r2oaixmnvzq6nnjuus0uowa6l&st=r7knws3r&dl=1";

export default async function handler(req: VercelRequest, res: VercelResponse) {
    // CORS headers
    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Access-Control-Allow-Methods', 'GET, OPTIONS');
    res.setHeader('Access-Control-Allow-Headers', 'Content-Type');

    if (req.method === 'OPTIONS') {
        return res.status(200).end();
    }

    try {
        console.log('[fetch-traffic] Fetching Traffic from Dropbox...');
        const response = await fetch(TRAFFIC_DROPBOX_URL);

        if (!response.ok) {
            throw new Error(`Dropbox responded with ${response.status}`);
        }

        const buffer = await response.arrayBuffer();
        console.log('[fetch-traffic] Successfully fetched Traffic Excel, size:', buffer.byteLength);

        res.setHeader('Content-Type', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
        res.status(200).send(Buffer.from(buffer));
    } catch (error: any) {
        console.error('[fetch-traffic] Error:', error);
        res.status(500).json({ error: error.message });
    }
}
