const Nav = (() => {
  "use strict";
  const TABS = [["stream", "Stream"], ["agents", "Agents"], ["artifacts", "Artifacts"]];
  const SUBS = {stream: [["inbox", "Inbox"], ["rules", "Regeln"]]};
  const VIEWS = [["orbit", "Orbit"], ["chord", "Chord"], ["swimlane", "Swimlane"], ["tree", "Tree"], ["3d", "3D"]];
  const OLD = {graph: ["agents", "orbit"], tree: ["artifacts", "tree"]};
  const known = (view) => VIEWS.some(([id]) => id === view);

  function tabOf(screen) {
    return Object.keys(SUBS).find((tab) => SUBS[tab].some(([id]) => id === screen)) || screen;
  }

  function hashOf(screen, view) {
    return tabOf(screen) === screen ? (view ? `#${screen}/${view}` : `#${screen}`) : `#${tabOf(screen)}/${screen}`;
  }

  function route(hash) {
    const [head, sub] = decodeURIComponent(String(hash).replace(/^#/, "")).split("/");
    if (Object.hasOwn(OLD, head)) {
      const [screen, fallback] = OLD[head];
      const view = known(sub) ? sub : fallback;
      return {screen, view, redirect: hashOf(screen, view)};
    }
    if (Object.hasOwn(SUBS, head) && SUBS[head].some(([id]) => id === sub)) {
      return {screen: sub, view: null, redirect: null};
    }
    if (TABS.some(([id]) => id === head) && head !== "stream") {
      return {screen: head, view: known(sub) ? sub : null, redirect: null};
    }
    return {screen: "stream", view: null, redirect: null};
  }

  return {TABS, SUBS, VIEWS, route, hashOf, tabOf};
})();
if (typeof module === "object" && module.exports) {
  module.exports = Nav;
}