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

const THEME_MODE_STORAGE_KEY = 'mumulingsi_theme_mode';
const LEGACY_THEME_MODE_STORAGE_KEY = 'xinmi_theme_mode';

const isThemeMode = (value: string | null): value is ThemeMode => {
  return value === 'light' || value === 'dark' || value === 'system';
};

export const getStoredThemeMode = (): ThemeMode => {
  try {
    let value = localStorage.getItem(THEME_MODE_STORAGE_KEY);
    if (!value) {
      value = localStorage.getItem(LEGACY_THEME_MODE_STORAGE_KEY);
      if (isThemeMode(value)) {
        localStorage.setItem(THEME_MODE_STORAGE_KEY, value);
        try {
          localStorage.removeItem(LEGACY_THEME_MODE_STORAGE_KEY);
        } catch {
          // ignore
        }
      }
    }
    if (isThemeMode(value)) {
      return value;
    }
  } catch (error) {
    console.warn('读取主题模式失败:', error);
  }

  return 'system';
};

export const setStoredThemeMode = (mode: ThemeMode): void => {
  try {
    localStorage.setItem(THEME_MODE_STORAGE_KEY, mode);
  } catch (error) {
    console.warn('保存主题模式失败:', error);
  }
};

export const getThemeModeStorageKey = (): string => THEME_MODE_STORAGE_KEY;