import ExecutionEnvironment from "@docusaurus/ExecutionEnvironment";

const MOC_VERSION = "0.7.2"; /* This may be slightly behind the base files we have locally in nix/sources.json */

async function addPackage(name, repo, version, dir) {
  const meta_url = `https://data.jsdelivr.com/v1/package/gh/${repo}@${version}/flat`;
  const base_url = `https://cdn.jsdelivr.net/gh/${repo}@${version}`;
  const response = await fetch(meta_url);
  const json = await response.json();
  const fetchedFiles = [];
  await Promise.all(json.files.map(async f => {
    if (f.name.startsWith(`/${dir}/`) && /\.mo$/.test(f.name)) {
      const content = await (await fetch(base_url + f.name)).text();
      const stripped = name + f.name.slice(dir.length + 1);
      fetchedFiles.push(stripped);
      await Motoko.saveFile(stripped, content);
    }
  }));
  await Motoko.addPackage(name, name + "/");
}

function attachOnRunButton() {
  if (document.getElementsByClassName("run-button").length > 0) {
    const script = document.createElement("script");
    script.async = true;
    script.src = `/moc_interpreter.js`;

    script.addEventListener("load", () => {
      addPackage("base", "dfinity/motoko-base", `moc-${MOC_VERSION}`, "src")
        .then(() => {
          console.log(`moc ${MOC_VERSION} loaded`);
          // Run code
          const btns = document.getElementsByClassName("run-button run");
          for (var i = 0; i < btns.length; i++) {
            btns[i].click();
          }
        });
    });
    document.head.appendChild(script);
  } else {
    console.log("motoko not loaded");
  }
}

if (
  ExecutionEnvironment.canUseDOM &&
  ExecutionEnvironment.canUseEventListeners
) {
  // As soon as the site loads in the browser, register a global event listener
  window.addEventListener("load", () => {
    attachOnRunButton();
  });
}

export function onRouteDidUpdate({ location, previousLocation }) {
  // Don't execute if we are still on the same page; the lifecycle may be fired
  // because the hash changes (e.g. when navigating between headings)
  if (location.pathname !== previousLocation?.pathname) {
    attachOnRunButton();
  }
}