const STORAGE_KEYS = {
  APP_STATE: 'font2svg:app-state',
  FAVORITES: 'font2svg:favorites',
}

function getStorage(key, fallbackValue) {
  try {
    const value = wx.getStorageSync(key)
    if (value === '' || value === undefined || value === null) {
      return fallbackValue
    }
    return value
  } catch (error) {
    console.warn('读取本地存储失败:', key, error)
    return fallbackValue
  }
}

function setStorage(key, value) {
  try {
    wx.setStorageSync(key, value)
  } catch (error) {
    console.warn('写入本地存储失败:', key, error)
  }
}

function loadAppState() {
  return getStorage(STORAGE_KEYS.APP_STATE, {})
}

function saveAppState(partialState) {
  const current = loadAppState()
  const next = {
    ...current,
    ...partialState,
    updatedAt: Date.now(),
  }
  setStorage(STORAGE_KEYS.APP_STATE, next)
  return next
}

function loadFavorites() {
  return getStorage(STORAGE_KEYS.FAVORITES, [])
}

function saveFavorites(favorites) {
  const unique = Array.from(new Set(favorites))
  setStorage(STORAGE_KEYS.FAVORITES, unique)
  return unique
}

module.exports = {
  STORAGE_KEYS,
  getStorage,
  setStorage,
  loadAppState,
  saveAppState,
  loadFavorites,
  saveFavorites,
}