// frontend/utils/cacheManager.js
// 缓存清理统一封装层
// 详见 docs/superpowers/specs/2026-07-28-cache-cleanup-design.md

import { invalidateAll } from './preloadApi/core'
import sandboxTmpHandler from './handlers/sandboxTmpHandler'
import progressHandler from './handlers/progressHandler'
import othersHandler from './handlers/othersHandler'
import preloadHandler from './handlers/preloadHandler'
import guideHandler from './handlers/guideHandler'
import draftHandler from './handlers/draftHandler'
import { getSandboxTotalSize, getDeviceStorageInfo } from './ioPath'

// ── 黑名单（§3.4.1）──
// 全等匹配
const PROTECTED_EXACT = new Set([
  'access_token', 'user', 'star_id', 'login_mobile', 'cid',
  'deviceFp', 'pending_scan_url', 'gallery_owner_id',
  'needs_welcome', 'has_seen_welcome', 'is_new_user',
  'liked_assets_exhibition',
])
// 前缀匹配
const PROTECTED_PREFIX = [
  'daily_login_completed_',
  'avatar_file_',
  'temp_register_',
]

/**
 * 判断 key 是否在黑名单中
 */
export function isProtectedKey(key) {
  if (typeof key !== 'string') return false
  if (PROTECTED_EXACT.has(key)) return true
  return PROTECTED_PREFIX.some((p) => key.startsWith(p))
}

// ── 大小格式化（§6.2）──
export function formatSize(bytes) {
  if (typeof bytes !== 'number' || bytes < 0) return '—'
  if (bytes < 1024) return '< 1 KB'
  const kb = bytes / 1024
  if (kb < 1024) return `${kb.toFixed(1)} KB`
  const mb = kb / 1024
  if (mb < 1024) return `${mb.toFixed(1)} MB`
  return `${(mb / 1024).toFixed(2)} GB`
}

// ── 内部状态 ──
const handlers = new Map()              // handlerId → handler
const cleanInFlight = new Map()         // `${id}` 或 `${id}#${uid}` → Promise

// ── 内存缓存：避免每次进 cache-cleanup 页都走 4 沙盒根遍历（最坏 ~2s） ──
// 5min TTL：
//   - 默认命中返回缓存（瞬时显示）
//   - 清理动作完成后调 deductFromCache() 局部扣减（不清空），下次返回列表仍命中
//   - invalidateCache() 仅用于特殊场景（如调试 / 用户主动重置）
const CACHE_TTL_MS = 5 * 60 * 1000
let _cachedInfo = null
let _cachedAt = 0

/** 清理缓存：清理动作完成后必须调用，下次 getCacheInfo 必重算 */
export function invalidateCache() {
  _cachedInfo = null
  _cachedAt = 0
}

/**
 * 清理后局部扣减缓存（不重算）：
 *   - 对应 category 的 sizeBytes / keyCount 扣减
 *   - totalBytes / appUsedBytes 同步扣减
 *   - usagePercent / deviceUsagePercent 重新计算
 * 不动 othersBytes（黑名单 + sandboxBytes 不直接减少；5min 内下次进页面会被 force=下拉刷新校正）
 *
 * 关键：必须创建新对象赋给 _cachedInfo，而不是 in-place 修改属性
 *   否则 cache-cleanup.vue 里 `info.value = cached` 检测到引用未变（Object.is 相等），
 *   不会触发 Vue 响应式更新 → 对应 category 的 sizeBytes 显示仍是旧值
 */
function deductFromCache(id, freedBytes, freedKeyCount) {
  if (!_cachedInfo || !Array.isArray(_cachedInfo.categories)) return

  const newCategories = _cachedInfo.categories.map((c) =>
    c.id === id
      ? {
          ...c,
          sizeBytes: Math.max(0, (c.sizeBytes || 0) - freedBytes),
          keyCount: Math.max(0, (c.keyCount || 0) - (freedKeyCount || 0)),
        }
      : c
  )
  const newAppUsedBytes = Math.max(0, (_cachedInfo.appUsedBytes || 0) - freedBytes)

  _cachedInfo = {
    ..._cachedInfo,
    categories: newCategories,
    totalBytes: Math.max(0, (_cachedInfo.totalBytes || 0) - freedBytes),
    appUsedBytes: newAppUsedBytes,
    usagePercent: _cachedInfo.quotaTotalBytes > 0
      ? (newAppUsedBytes / _cachedInfo.quotaTotalBytes) * 100
      : 0,
    deviceUsagePercent: _cachedInfo.deviceTotalBytes > 0
      ? (newAppUsedBytes / _cachedInfo.deviceTotalBytes) * 100
      : 0,
  }
  _cachedAt = Date.now()
}

/**
 * 同步检查缓存：命中且未过期 → 直接返回缓存对象（不走 spinner）
 * 否则返回 null（需要走 getCacheInfo 异步计算）
 */
export function peekCache() {
  if (_cachedInfo && Date.now() - _cachedAt < CACHE_TTL_MS) {
    return _cachedInfo
  }
  return null
}

// ── 注册 API ──
export function registerCategory(handler) {
  if (!handler?.id) throw new Error('[cacheManager] handler.id is required')
  handlers.set(handler.id, handler)
}

function getHandler(id) {
  const h = handlers.get(id)
  if (!h) throw new Error(`[cacheManager] unknown handler: ${id}`)
  return h
}

// ── 公共 API ──

/**
 * 列表页读取（汇总 + 存储配额 + 其他 section 数据）
 * @param {boolean} force 强制重算（跳过 30s 缓存）；下拉刷新/清理后用
 */
export async function getCacheInfo(force = false) {
  // 缓存命中：30s 内且不强制刷新 → 同步返回，避免重复走沙盒遍历
  const now = Date.now()
  if (!force && _cachedInfo && now - _cachedAt < CACHE_TTL_MS) {
    return _cachedInfo
  }
  // 缓存未命中或过期或强制刷新 → 重新计算
  // [并行 1] 所有 handler 的 computeSize
  const categories = await Promise.all(
    Array.from(handlers.values()).map(async (h) => {
      try {
        const info = await h.computeSize()
        return { id: h.id, label: h.label, description: h.description || '', sizeBytes: info?.sizeBytes ?? 0, keyCount: info?.keyCount ?? 0, warning: !!h.warning }
      } catch (e) {
        console.warn(`[cacheManager] computeSize failed: ${h.id}`, e.message)
        return { id: h.id, label: h.label, description: h.description || '', sizeBytes: -1, keyCount: 0, warning: !!h.warning, error: e.message }
      }
    })
  )

  // [串行] 配额 + 黑名单 + 沙盒
  let currentSizeKB = 0, limitSizeKB = 0, sandboxBytes = 0, blacklistBytes = 0
  try {
    const info = uni.getStorageInfoSync()
    currentSizeKB = info.currentSize || 0
    limitSizeKB = info.limitSize || 0
    const allKeys = info.keys || []
    // 黑名单 key 大小
    for (const k of allKeys) {
      if (isProtectedKey(k)) {
        try {
          const v = uni.getStorageSync(k)
          if (v != null) blacklistBytes += JSON.stringify(v).length
        } catch (e) { /* skip */ }
      }
    }
  } catch (e) {
    console.warn('[cacheManager] getStorageInfoSync failed:', e.message)
  }
  try {
    sandboxBytes = await getSandboxTotalSize()
  } catch (e) {
    console.warn('[cacheManager] getSandboxTotalSize failed:', e.message)
  }
  let deviceTotalBytes = 0, deviceFreeBytes = 0
  try {
    const dev = await getDeviceStorageInfo()
    // ioPath.getDeviceStorageInfo 返回的 totalBytes/freeBytes 已是字节（Android: blockSize*blocks, iOS: NSFileSystemSize），不要再 * 1024
    deviceTotalBytes = dev.totalBytes || 0
    deviceFreeBytes = dev.freeBytes || 0
  } catch (e) {
    console.warn('[cacheManager] getDeviceStorageInfo failed:', e.message)
  }

  const totalBytes = categories.reduce((sum, c) => sum + (c.sizeBytes > 0 ? c.sizeBytes : 0), 0)
  const appUsedBytes = currentSizeKB * 1024 + sandboxBytes
  const quotaTotalBytes = limitSizeKB * 1024
  const raw = quotaTotalBytes - appUsedBytes
  const quotaAvailableBytes = Math.max(0, raw)
  const quotaExceeded = raw < 0
  const usagePercent = quotaTotalBytes > 0 ? (appUsedBytes / quotaTotalBytes) * 100 : 0
  // 设备级数据已在 try 块里取好（ioPath 返回的就是字节，不再 * 1024）
  const deviceUsagePercent = deviceTotalBytes > 0
    ? (appUsedBytes / deviceTotalBytes) * 100
    : 0

  const result = {
    totalBytes, appUsedBytes, quotaTotalBytes, quotaAvailableBytes, quotaExceeded, usagePercent,
    deviceTotalBytes, deviceFreeBytes, deviceUsagePercent,
    othersBytes: blacklistBytes + sandboxBytes,
    categories,
  }
  // 写入缓存（即便部分字段失败/降级也缓存，避免反复重算；清理动作会主动 invalidate）
  _cachedInfo = result
  _cachedAt = Date.now()
  return result
}

/**
 * 详情页读取（分组详情；简单 handler 返回 null）
 */
export async function getCategoryBreakdown(id) {
  const h = getHandler(id)
  if (typeof h.computeBreakdown !== 'function') return null
  try {
    return await h.computeBreakdown()
  } catch (e) {
    console.warn(`[cacheManager] computeBreakdown failed: ${id}`, e.message)
    return []
  }
}

/**
 * 简单页清理（无分组维度）
 */
export function cleanCategory(id) {
  return _runWithInFlight(`${id}`, async () => {
    const h = getHandler(id)
    if (typeof h.clean !== 'function') {
      throw new Error(`[cacheManager] handler ${id} has no clean() (use cleanCategoryGroup)`)
    }
    try {
      const result = await h.clean()
      // preload 清理同步清内存（§3.4.4）
      if (id === 'preload') {
        try { invalidateAll() } catch (e) { console.warn('[cacheManager] invalidateAll failed:', e.message) }
      }
      // 局部扣减缓存（不清空）：返回列表页时 cache-cleanup 还能命中缓存，瞬时显示新数据
      const { freedBytes = 0, keyCount = 0 } = result || {}
      deductFromCache(id, freedBytes, keyCount)
      return result
    } catch (e) {
      console.warn(`[cacheManager] clean failed: ${id}`, e.message)
      throw e
    }
  })
}

/**
 * 分组页清理（按 uid 维度）
 * @param {string} id
 * @param {object} opts
 * @param {string|null} opts.uid  'self' = 当前用户，null = 其他用户聚合，其他 = 具体 uid 字符串
 */
export function cleanCategoryGroup(id, opts = {}) {
  const uidKey = opts.uid === undefined ? 'self' : String(opts.uid)
  return _runWithInFlight(`${id}#${uidKey}`, async () => {
    const h = getHandler(id)
    if (typeof h.cleanGroup !== 'function') {
      throw new Error(`[cacheManager] handler ${id} has no cleanGroup() (use cleanCategory)`)
    }
    try {
      const result = await h.cleanGroup({ uid: opts.uid === undefined ? 'self' : opts.uid })
      if (id === 'preload') {
        try { invalidateAll() } catch (e) { console.warn('[cacheManager] invalidateAll failed:', e.message) }
      }
      // 局部扣减缓存（不清空）
      const { freedBytes = 0, keyCount = 0 } = result || {}
      deductFromCache(id, freedBytes, keyCount)
      return result
    } catch (e) {
      console.warn(`[cacheManager] cleanGroup failed: ${id}`, e.message)
      throw e
    }
  })
}

/**
 * 编程式清理所有（UI 不调用；登出流程/测试用）
 * 对每个 handler 调用其支持的清理方法：
 *   - 优先 clean()（简单型）
 *   - 否则调 cleanGroup({ uid: 'self' })（仅清当前用户的分组数据，符合"登出前清自己"的语义）
 */
export async function cleanAll() {
  const results = []
  for (const h of handlers.values()) {
    try {
      let r
      if (typeof h.clean === 'function') {
        r = await h.clean()
      } else if (typeof h.cleanGroup === 'function') {
        r = await h.cleanGroup({ uid: 'self' })
      } else {
        continue
      }
      results.push({ id: h.id, ...r, error: null })
    } catch (e) {
      console.warn(`[cacheManager] cleanAll failed for ${h.id}:`, e.message)
      results.push({ id: h.id, freedBytes: 0, keyCount: 0, error: e.message })
    }
  }
  try { invalidateAll() } catch (e) { console.warn('[cacheManager] cleanAll invalidateAll failed:', e.message) }
  return { freedBytes: results.reduce((s, r) => s + (r.freedBytes || 0), 0), perCategory: results }
}

// NOTE: 必须非 async —— async 会把返回的 Promise 再包一层，破坏
// `p1 === p2` 同一性断言（参见 plan §Task 12 Step 2 自测）。
// 这里需要直接返回存储在 cleanInFlight 中的 Promise 引用本身。
function _runWithInFlight(key, fn) {
  if (cleanInFlight.has(key)) return cleanInFlight.get(key)
  const p = (async () => {
    try { return await fn() } finally { cleanInFlight.delete(key) }
  })()
  cleanInFlight.set(key, p)
  return p
}

// ── Handler 注册（模块加载时执行；新增 handler 在此追加 registerCategory 调用）──
registerCategory(sandboxTmpHandler)
registerCategory(progressHandler)
registerCategory(othersHandler)
registerCategory(preloadHandler)
registerCategory(guideHandler)
registerCategory(draftHandler)