/**
 * Proxies Hail Recon API calls from the browser.
 * Solves CORS and keeps credentials server-side.
 *
 * Usage: GET /api/hail-proxy?endpoint=ImpactDatesForLatLong&Lat=33.055&Long=-96.752&Months=12
 *        POST /api/hail-proxy?endpoint=AddressMonitoringImport2g  (body = JSON payload)
 */

const BASE_URL = 'https://maps.interactivehailmaps.com/ExternalApi';

const ALLOWED_ENDPOINTS = new Set([
    'ImpactDatesForLatLong',
    'ImpactDatesForAddressMarker',
    'AddressMonitoringImport2g',
]);

export default async function handler(req, res) {
    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
    res.setHeader('Access-Control-Allow-Headers', 'Content-Type');

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

    const { endpoint, ...params } = req.query;

    if (!endpoint || !ALLOWED_ENDPOINTS.has(endpoint)) {
        return res.status(400).json({ error: 'Invalid or missing endpoint' });
    }

    const accessKey    = process.env.HAIL_RECON_ACCESS_KEY;
    const accessSecret = process.env.HAIL_RECON_ACCESS_SECRET;

    if (!accessKey || !accessSecret) {
        return res.status(500).json({ error: 'Hail Recon credentials not configured' });
    }

    const credentials = Buffer.from(`${accessKey}:${accessSecret}`).toString('base64');
    const authHeader  = `Basic ${credentials}`;

    try {
        let response;

        if (req.method === 'POST') {
            response = await fetch(`${BASE_URL}/${endpoint}`, {
                method: 'POST',
                headers: {
                    'Authorization': authHeader,
                    'Content-Type': 'application/json',
                },
                body: JSON.stringify(req.body),
            });
        } else {
            const qs = new URLSearchParams(params).toString();
            const url = `${BASE_URL}/${endpoint}${qs ? `?${qs}` : ''}`;
            response = await fetch(url, {
                headers: { 'Authorization': authHeader },
            });
        }

        const contentType = response.headers.get('content-type') || '';
        const data = contentType.includes('application/json')
            ? await response.json()
            : await response.text();

        return res.status(response.status).json(data);
    } catch (err) {
        return res.status(502).json({ error: 'Failed to reach Hail Recon API', detail: err.message });
    }
}