export const THEME_STORAGE_KEY = "confidence-engine-theme";

export function resolveTheme({ savedTheme, systemPrefersDark = false } = {}) {
  if (savedTheme === "light" || savedTheme === "dark") return savedTheme;
  return systemPrefersDark ? "dark" : "light";
}

export function toggleTheme(theme) {
  return theme === "dark" ? "light" : "dark";
}

export function readThemePreference(storage) {
  try {
    return storage?.getItem(THEME_STORAGE_KEY) ?? null;
  } catch {
    return null;
  }
}

export function saveThemePreference(theme, storage) {
  storage?.setItem(THEME_STORAGE_KEY, theme);
}