(() => {
  const rendererUrl = new URL(
    "../assets/vendor/mathjax/tex-mml-chtml.js",
    document.currentScript.src
  );
  const assetRoot = new URL(".", rendererUrl).href.replace(/\/$/, "");
  let loading;
  let revision = 0;
  let rendering = Promise.resolve();

  function loadMathJax() {
    if (loading) {
      return loading;
    }

    window.MathJax = {
      loader: {
        paths: {
          mathjax: assetRoot,
          sre: `${assetRoot}/sre/mathmaps`
        }
      },
      tex: {
        inlineMath: [["\\(", "\\)"]],
        displayMath: [["\\[", "\\]"]],
        processEscapes: true,
        processEnvironments: true
      },
      options: {
        ignoreHtmlClass: ".*|",
        processHtmlClass: "arithmatex"
      },
      chtml: {
        fontURL: `${assetRoot}/output/chtml/fonts/woff-v2`
      },
      startup: {
        typeset: false
      }
    };

    loading = new Promise((resolve, reject) => {
      const script = document.createElement("script");
      script.src = rendererUrl.href;
      script.async = true;
      script.onload = () => {
        window.MathJax.startup.promise.then(() => resolve(window.MathJax), reject);
      };
      script.onerror = () => {
        loading = undefined;
        script.remove();
        reject(new Error(`Failed to load MathJax from ${rendererUrl.href}`));
      };
      document.head.append(script);
    });
    return loading;
  }

  document$.subscribe(() => {
    const currentRevision = ++revision;

    // Serialize rendering and discard navigation events superseded during loading.
    rendering = rendering.then(async () => {
      if (currentRevision !== revision) {
        return;
      }
      const content = document.querySelector(".md-content");
      if (!content || !content.querySelector(".arithmatex")) {
        if (loading) {
          const mathjax = await loading;
          mathjax.typesetClear();
        }
        return;
      }

      const mathjax = await loadMathJax();
      if (currentRevision !== revision) {
        return;
      }
      mathjax.startup.output.clearCache();
      mathjax.typesetClear();
      mathjax.texReset();
      await mathjax.typesetPromise([content]);
    }).catch(error => {
      console.error("Jupiter Notes: unable to render mathematics.", error);
    });
  });
})();