(() => {
  "use strict";

  const STORAGE_KEY = "cognitive-agent.glass-theme";

  function normalizeTheme(value) {
    return value === "light" ? "light" : value === "dark" ? "dark" : "";
  }

  function themeFromCookie() {
    try {
      return normalizeTheme(document.cookie
        .split(";")
        .map((part) => part.trim())
        .find((part) => part.startsWith(`${STORAGE_KEY}=`))
        ?.slice(STORAGE_KEY.length + 1));
    } catch (_error) {
      return "";
    }
  }

  function resolveInitialTheme() {
    const requested = normalizeTheme(new URLSearchParams(window.location.search).get("theme"));
    if (requested) return requested;
    try {
      const parentTheme = normalizeTheme(window.parent?.document?.documentElement?.dataset?.glassTheme);
      if (parentTheme) return parentTheme;
    } catch (_error) {
      // Standalone and cross-origin rendering continue with local preferences.
    }
    try {
      const stored = normalizeTheme(localStorage.getItem(STORAGE_KEY));
      if (stored) return stored;
    } catch (_error) {
      // Storage may be unavailable in hardened browser contexts.
    }
    return themeFromCookie() || "dark";
  }

  function applyTheme(theme) {
    const normalized = normalizeTheme(theme) || "dark";
    document.documentElement.dataset.glassTheme = normalized;
    document.documentElement.style.colorScheme = normalized;
    document.querySelector("#firmwareWorkbenchThemeColor")
      ?.setAttribute("content", normalized === "dark" ? "#0f1526" : "#f3f6fb");
    return normalized;
  }

  applyTheme(resolveInitialTheme());

  window.addEventListener("storage", (event) => {
    if (event.key === STORAGE_KEY) applyTheme(event.newValue);
  });
  window.addEventListener("message", (event) => {
    if (event.origin !== window.location.origin) return;
    if (window.parent !== window && event.source !== window.parent) return;
    if (event.data?.type !== "cognitive-agent:theme-change") return;
    applyTheme(event.data.theme);
  });

  window.CognitiveAgentFirmwareWorkbenchTheme = Object.freeze({
    apply: applyTheme,
    current: () => document.documentElement.dataset.glassTheme,
  });
})();