// Hides the react root element.
// If fade is true, it will fade out the root element before removing it completely.
// If fade is false, it will remove the root element immediately without any animations.
function removeReactRoot(fade = true) {
  const root = document.getElementById("root");
  if (!root) {
    console.warn("No Root element found.");
    return;
  }

  if (fade) {
    root.style.transition = "opacity 0.3s ease";
    root.style.opacity = 0;
    setTimeout(() => root.style.display = "none", 300);
  } else {
    root.style.display = "none";
  }
}

// Show Flutter immediately with standard fluter_bootstrap.js.
// This is how flutter boots up for a pure flutter web app.
// We use this to skip the React landing page and boot Flutter directly.
// This is useful for apps that don't need a React landing page.
// e.g. logged in, or routing to a page under Flutter control like /login, or /pricing, etc.
function bootFlutterNow() {
  console.log("Booting Flutter immediately...");

  // 1. First thing we do is remove the React root element so it doesn't render and overlay Flutter's canvas.
  removeReactRoot(false);

  // 2. Inject flutter_bootstrap.js script to load Flutter.
  // Note that we don't need to show flutter container here as flutter_bootstrap.js will show it automatically,
  // rendering flutter-container div useless.
  const script = document.createElement("script");
  // Use new URL with document.baseURI to respect <base> tag for subdirectory deployments
  script.src = new URL("flutter_bootstrap.js", document.baseURI).href;
  script.defer = true;
  document.body.appendChild(script);
}

/// Starts loading Flutter in the background, when the landing page is shown.
/// Adds a click handler to the "Get Started" button to show Flutter when clicked.
function backgroundLoadFlutter() {

  console.log("Starting background load of Flutter...");
  // Skip if already initialized
  if (window.__flutterLoaderInit) return;
  window.__flutterLoaderInit = true;

  // 1. Preload Flutter on page load.
  window.addEventListener("load", () => {
    console.log("Loading Flutter engine...");
    _flutter.loader.loadEntrypoint({
      // Use new URL with document.baseURI to respect <base> tag for subdirectory deployments
      entrypointUrl: new URL("main.dart.js", document.baseURI).href,
      onEntrypointLoaded: async (initializer) => {
        console.log("Flutter entrypoint loaded, initializing engine...");
        const appRunner = await initializer.initializeEngine({
          hostElement: document.getElementById("flutter_host"),
        });

        // Expose to window object for React bridge
        window.__flutterAppRunner = appRunner;
        window.__flutterAppLoaded = true;

        console.log("Flutter engine initialized successfully");
        console.log("✅ Set window.__flutterAppRunner:", !!window.__flutterAppRunner);
        console.log("✅ Set window.__flutterAppLoaded:", window.__flutterAppLoaded);
      }
    });
  });

  // Normal click handler for Get Started
  async function onClickHandler() {
    if (window.__flutterAppLoaded) {
      // Show the Flutter container
      const f = document.getElementById("flutter-container");
      f.style.display = "block";

      // Remove react root element to prevent React from rendering over Flutter.
      removeReactRoot();

      // Start Flutter app if not already running
      if (!window.__flutterAppRunning) {
        await window.__flutterAppRunner.runApp();
        window.__flutterAppRunning = true;
      }
    } else {
      console.warn("Flutter app not loaded yet, waiting...");
      setTimeout(onClickHandler, 100);
    }
  }

  // Note: Button click handlers are managed by React via switchToFlutterApp()
  // No need to attach button listeners here
};

function isUserLoggedIn() {
  // ✅ Check if user is already logged in via localStorage.
  // If user data is found, skip the landing page and load Flutter directly.
  // Load landing page otherwise.
  const userData = localStorage.getItem("user");
  if (!userData) return false;

  try {
    let parsedUser = JSON.parse(userData);
    if (typeof parsedUser === "string") {
      parsedUser = JSON.parse(parsedUser); // double parse if needed
    }
    return parsedUser && parsedUser.uid;
  } catch (err) {
    console.warn("Error parsing localStorage user", err);
    return false;
  }
}

// List of routes that React should handle
const reactRoutes = ["/about", "/contact", "/terms", "/privacy", "/view"];

// ✅ If current route is not root or any of the above React routes, let flutter render immediately.
if (window.location.pathname == "/") {
  if (isUserLoggedIn()) {
    console.log("User is logged in, booting Flutter immediately...");
    bootFlutterNow();
  } else {
    console.log("User is not logged in, showing landing page...");
    backgroundLoadFlutter();
  }
  // The route is root or one of the React routes, so we show the landing page.
} else if (!reactRoutes.includes(window.location.pathname)) {
  // Non-root path detected, but not a React route. So it is likely a Flutter route.
  console.log(`Non-root path detected (${window.location.pathname}) → skipping landing page`);
  bootFlutterNow();
} else {
  console.log("Showing landing page for React routes...");
  backgroundLoadFlutter();
}