// Low-level stream probe.
// Icecast/SHOUTcast servers commonly answer with `ICY 200 OK` instead of
// `HTTP/1.1 200 OK`, which Node's built-in fetch refuses to parse. We open
// a raw TCP/TLS socket, send a minimal HTTP/1.0 GET, and inspect the first
// status line ourselves.

import net from 'node:net';
import tls from 'node:tls';

const TIMEOUT = 8000;
const UA = 'Mozilla/5.0 OnlineRadioExplorer/0.1';

export function probeStream(rawUrl) {
    return new Promise((resolve) => {
        let url;
        try { url = new URL(rawUrl); } catch { return resolve('err-badurl'); }

        const isTls = url.protocol === 'https:';
        const port = Number(url.port) || (isTls ? 443 : 80);
        const path = (url.pathname || '/') + (url.search || '');
        const host = url.hostname;

        const opts = { host, port, servername: host };
        const connect = isTls ? tls.connect : net.connect;
        const sock = connect(opts);

        let settled = false;
        const finish = (status) => {
            if (settled) return;
            settled = true;
            try { sock.destroy(); } catch { }
            resolve(status);
        };

        sock.setTimeout(TIMEOUT);
        sock.on('timeout', () => finish('err-timeout'));
        sock.on('error', () => finish('err-fetch'));

        sock.on('connect', () => {
            const req =
                `GET ${path} HTTP/1.0\r\n` +
                `Host: ${host}\r\n` +
                `User-Agent: ${UA}\r\n` +
                `Icy-MetaData: 1\r\n` +
                `Accept: */*\r\n` +
                `Connection: close\r\n\r\n`;
            sock.write(req);
        });

        let buf = '';
        sock.on('data', (chunk) => {
            buf += chunk.toString('latin1');
            const eol = buf.indexOf('\n');
            if (eol < 0) return;
            const statusLine = buf.slice(0, eol).trim();
            // Accept: HTTP/1.x 2xx, ICY 2xx, SOURCE 2xx
            const m = statusLine.match(/^(?:HTTP\/\d\.\d|ICY|SOURCE)\s+(\d{3})/i);
            if (!m) return finish(`bad-${statusLine.slice(0, 16)}`);
            const code = Number(m[1]);
            if (code >= 200 && code < 400) finish('up');
            else finish(`http-${code}`);
        });

        sock.on('end', () => {
            if (!settled) finish(buf ? 'err-empty' : 'err-fetch');
        });
    });
}