const CURRENT_GENEALOGY_KEY = 'jiapu_current_genealogy_id'
const CURRENT_GENEALOGY_INVALIDATED_KEY = 'jiapu_current_genealogy_invalidated'

const normalizeGenealogyId = (genealogyId) => {
  if (typeof genealogyId !== 'string') {
    throw new TypeError('当前家谱 ID 必须是词法字符串')
  }
  if (!genealogyId || genealogyId.trim() !== genealogyId || /[\u0000-\u001f\u007f]/.test(genealogyId)) {
    throw new TypeError('当前家谱 ID 必须是无边界空白的非空字符串')
  }
  return genealogyId
}

const markCurrentGenealogyInvalidated = () => {
  uni.removeStorageSync(CURRENT_GENEALOGY_KEY)
  uni.setStorageSync(CURRENT_GENEALOGY_INVALIDATED_KEY, '1')
}

const readCurrentGenealogyInvalidated = () => {
  const stored = uni.getStorageSync(CURRENT_GENEALOGY_INVALIDATED_KEY)
  if (stored === '' || stored === null || stored === undefined) return false
  if (stored !== '1') uni.setStorageSync(CURRENT_GENEALOGY_INVALIDATED_KEY, '1')
  return true
}

const readCurrentGenealogyId = () => {
  const stored = uni.getStorageSync(CURRENT_GENEALOGY_KEY)
  if (stored === '' || stored === null || stored === undefined) return ''
  try {
    return normalizeGenealogyId(stored)
  } catch {
    // 旧版本或损坏的存储值不应继续流入路由和权限判断。发现异常时只清理
    // 这一唯一键；下一次取得可用家谱列表后再按确定顺序建立新上下文。
    markCurrentGenealogyInvalidated()
    return ''
  }
}

export const genealogyContext = {
  getCurrentGenealogyId: readCurrentGenealogyId,
  setCurrentGenealogyId: (genealogyId) => {
    const normalizedId = normalizeGenealogyId(genealogyId)
    uni.setStorageSync(CURRENT_GENEALOGY_KEY, normalizedId)
    uni.removeStorageSync(CURRENT_GENEALOGY_INVALIDATED_KEY)
    return normalizedId
  },
  invalidateCurrentGenealogyId: () => {
    markCurrentGenealogyInvalidated()
    return ''
  },
  isCurrentGenealogyInvalidated: readCurrentGenealogyInvalidated,
  clearCurrentGenealogyId: () => {
    uni.removeStorageSync(CURRENT_GENEALOGY_KEY)
    uni.removeStorageSync(CURRENT_GENEALOGY_INVALIDATED_KEY)
  },
  reconcileCurrentGenealogyId: (availableIds, preferredId = '') => {
    if (!Array.isArray(availableIds)) {
      throw new TypeError('可用家谱 ID 必须是数组')
    }
    const normalizedIds = availableIds.map(normalizeGenealogyId)
    if (new Set(normalizedIds).size !== normalizedIds.length) {
      throw new TypeError('可用家谱列表包含重复 ID')
    }
    const normalizedPreferredId = preferredId === ''
      ? ''
      : normalizeGenealogyId(preferredId)
    const storedId = readCurrentGenealogyId()
    if (normalizedPreferredId) {
      if (!normalizedIds.includes(normalizedPreferredId)) {
        markCurrentGenealogyInvalidated()
        return ''
      }
      return genealogyContext.setCurrentGenealogyId(normalizedPreferredId)
    }
    if (storedId) {
      if (!normalizedIds.includes(storedId)) {
        markCurrentGenealogyInvalidated()
        return ''
      }
      return genealogyContext.setCurrentGenealogyId(storedId)
    }
    if (readCurrentGenealogyInvalidated()) return ''
    if (!normalizedIds.length) {
      uni.removeStorageSync(CURRENT_GENEALOGY_KEY)
      return ''
    }
    return genealogyContext.setCurrentGenealogyId(normalizedIds[0])
  }
}