// frontend/utils/handlers/preloadHandler.js
// preload 缓存 handler（简单型，但跨用户清理 + invalidateAll）
// 跨用户：删除所有 preload:xxx:* 不依赖 currentUid
// 内存清理：由 cacheManager.cleanCategory 触发 invalidateAll

const PREFIX = 'preload:'

function listAllPreloadKeys() {
  try {
    const info = uni.getStorageInfoSync()
    return (info.keys || []).filter((k) => k.startsWith(PREFIX))
  } catch (e) { return [] }
}

export default {
  id: 'preload',
  label: '预加载数据缓存',
  description: '列表页提前拉取的数据',
  warning: false,
  async computeSize() {
    const keys = listAllPreloadKeys()
    let bytes = 0
    for (const k of keys) {
      try { const v = uni.getStorageSync(k); if (v != null) bytes += JSON.stringify(v).length } catch (e) {}
    }
    return { sizeBytes: bytes, keyCount: keys.length }
  },
  async clean() {
    const keys = listAllPreloadKeys()
    let freed = 0
    let count = 0
    for (const k of keys) {
      let valueBytes = 0
      try {
        const v = uni.getStorageSync(k)
        if (v != null) valueBytes = JSON.stringify(v).length
      } catch (e) {
        console.warn('[preloadHandler] read failed:', k, e.message)
        continue
      }
      try {
        uni.removeStorageSync(k)
        freed += valueBytes
        count++
      } catch (e) {
        console.warn('[preloadHandler] remove failed:', k, e.message)
      }
    }
    return { freedBytes: freed, keyCount: count }
  },
}