cache.js

// 查询结果缓存 - 服务端内存缓存，用于二次查找和分页
const cache = new Map()

// 缓存过期时间（毫秒），默认30分钟
const CACHE_TTL = 30 * 60 * 1000

// 定时清理过期缓存
setInterval(() => {
  const now = Date.now()
  for (const [key, value] of cache) {
    if (now - value.createdAt > CACHE_TTL) {
      cache.delete(key)
    }
  }
}, 60 * 1000)

// 存储查询结果
export function setCache(queryId, data) {
  cache.set(queryId, {
    data,
    columns: Object.keys(data[0] || {}),
    createdAt: Date.now(),
    totalCount: data.length,
  })
}

// 获取缓存的查询结果
export function getCache(queryId) {
  const entry = cache.get(queryId)
  if (!entry) return null
  if (Date.now() - entry.createdAt > CACHE_TTL) {
    cache.delete(queryId)
    return null
  }
  return entry
}

// 在缓存中二次查找
export function searchInCache(queryId, keyword) {
  const entry = getCache(queryId)
  if (!entry) return null

  if (!keyword || keyword.trim() === '') {
    return entry
  }

  const lowerKeyword = keyword.toLowerCase()
  const filtered = entry.data.filter(row =>
    entry.columns.some(col => {
      const val = row[col]
      if (val === null || val === undefined) return false
      return String(val).toLowerCase().includes(lowerKeyword)
    })
  )

  return {
    ...entry,
    data: filtered,
    totalCount: filtered.length,
  }
}

// 删除缓存
export function deleteCache(queryId) {
  cache.delete(queryId)
}

// 清理所有缓存
export function clearAllCache() {
  cache.clear()
}