// Static assets + HTTP Range for /video/* (Safari/iOS will not play video without 206 responses)
export default {
  async fetch(req, env) {
    const url = new URL(req.url);
    const range = req.headers.get('Range');
    if (!url.pathname.startsWith('/video/') || !range) return env.ASSETS.fetch(req);

    const full = await env.ASSETS.fetch(new Request(url, { method: 'GET' }));
    if (!full.ok) return full;
    const buf = await full.arrayBuffer(), size = buf.byteLength;
    const m = /^bytes=(\d*)-(\d*)$/.exec(range.trim());
    let start, end;
    if (m && m[1] !== '') { start = +m[1]; end = m[2] !== '' ? Math.min(+m[2], size - 1) : size - 1; }
    else if (m && m[2] !== '') { start = Math.max(0, size - +m[2]); end = size - 1; }
    if (!m || start > end || start >= size)
      return new Response(null, { status: 416, headers: { 'Content-Range': `bytes */${size}` } });

    const h = new Headers(full.headers);
    h.set('Content-Range', `bytes ${start}-${end}/${size}`);
    h.set('Content-Length', String(end - start + 1));
    h.set('Accept-Ranges', 'bytes');
    return new Response(req.method === 'HEAD' ? null : buf.slice(start, end + 1), { status: 206, headers: h });
  },
};