// Radar's one script (spec §17.3): when the event stream says something

// changed, fetch this page again and replace <main>. Pages work without it.

(function () {

  var main = document.querySelector("main[data-live]");

  if (!main || !window.EventSource) return;

  var timer = null;

  function refresh() {

    fetch(location.href, { credentials: "same-origin" }).then(function (r) { return r.ok ? r.text() : null; }).then(function (html) {

      if (!html) return;

      var next = new DOMParser().parseFromString(html, "text/html").querySelector("main");

      var active = document.activeElement;

      if (next && !(active && (active.tagName === "TEXTAREA" || active.tagName === "INPUT") && active.value)) main.innerHTML = next.innerHTML;

    });

  }

  var es = new EventSource("/radar/events");

  es.onmessage = function () { clearTimeout(timer); timer = setTimeout(refresh, 300); };

})();