let requestURL = $request.url;

if(requestURL.indexOf('/Videos/') != -1 && (requestURL.indexOf('/stream/') != -1 || requestURL.indexOf('/Subtitles/') != -1) ){
  let query = getQueryVariable(requestURL);
  if (typeof(query['filename']) == "undefined" || query['filename'] == "") {
    $done({});
  }
  $response.headers['Content-Disposition'] = 'attachment;filename=' + decodeURI(query['filename']);
  $done({
    status: 200,
    headers: $response.headers
  });
}else {
  $done({});
}

function getQueryVariable(url) {
  let index = url.lastIndexOf('?');
  let query = url.substring(index + 1, url.length);
  let vars = query.split("&");
  let querys = new Object();
  for (let i = 0; i < vars.length; i++) {
    let pair = vars[i].split("=");
    querys[pair[0]] = pair[1]
  }
  if (Object.keys(querys).length == 0) {
    return null;
  } else {
    return querys;
  }
}