export const THEME_STORAGE_KEY = 'dyolink-theme';

export type ThemeMode = 'light' | 'dark';

export function getStoredTheme(): ThemeMode {
  if (typeof window === 'undefined') return 'dark';
  try {
    const v = localStorage.getItem(THEME_STORAGE_KEY);
    if (v === 'light' || v === 'dark') return v;
  } catch {
    /* ignore */
  }
  return 'dark';
}

export function applyTheme(mode: ThemeMode) {
  if (typeof document === 'undefined') return;
  document.documentElement.setAttribute('data-theme', mode);
  try {
    localStorage.setItem(THEME_STORAGE_KEY, mode);
  } catch {
    /* ignore */
  }
}

export function toggleTheme(): ThemeMode {
  const next: ThemeMode = getStoredTheme() === 'dark' ? 'light' : 'dark';
  applyTheme(next);
  return next;
}