/**
 * 全局数据状态（模块级 reactive 单例，多页面共享）
 * - packages：包列表（已排序：预警置顶 → 正常 → 忽略）
 * - thresholds：全局阈值 + 单包例外
 * - logs：操作日志
 */
import { reactive, computed } from 'vue'
import api from '../api'

const state = reactive({
  packages: [],
  threshold: { versionThreshold: 15, sizeThreshold: 500, exceptions: [] },
  logs: [],
  loading: false,
  scannedAt: null,
  storageDir: localStorage.getItem('vcm-storage-dir') || '',
  // 后端目录扫描总字节（所有文件，与 du 同口径；null 表示未知/演示模式）
  totalBytes: null,
  // 扫描进度（异步扫描期间实时更新，用于遮罩展示）
  scanProgress: { packages: 0, bytes: 0 },
})

// —— 派生统计 ——
const stats = computed(() => {
  const valid = state.packages.filter(p => p.status !== 'broken')
  // 总占用统计全部物理缓存（含元数据异常的包，其大小按实际 .tgz 计算）
  const totalSize = state.packages.reduce((s, p) => s + p.size, 0)
  const warnCount = valid.filter(p => p.status === 'warn').length
  const cleanable = valid.filter(p => p.status === 'warn').reduce((s, p) => s + p.size, 0)
  const maxPkg = [...valid].sort((a, b) => b.size - a.size)[0] || null
  const oldestPkg = [...valid].sort((a, b) => (a.lastUpdated || '').localeCompare(b.lastUpdated || ''))[0] || null
  // 今日更新包数：最近更新时间等于今天的包数量
  const d = new Date()
  const todayStr = `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, '0')}-${String(d.getDate()).padStart(2, '0')}`
  const todayUpdated = valid.filter(p => (p.lastUpdated || '') === todayStr).length
  // 真实环境无访问统计（visits 全 0）时，Top20 降级为「缓存占用 Top 20」
  const hasVisits = valid.some(p => (p.visits || 0) > 0)
  const top30 = [...valid]
    .sort((a, b) => (hasVisits ? (b.visits || 0) - (a.visits || 0) : b.size - a.size))
    .slice(0, 20)
  const maxVisit = Math.max(...top30.map(p => p.visits || 0), 1)
  const maxSize = Math.max(...top30.map(p => p.size), 1)
  return {
    pkgCount: valid.length,
    totalVersions: state.packages.reduce((s, p) => s + (p.versions || 0), 0),
    totalSize,
    // 总占用优先用后端「目录所有文件字节和」（与 du 一致），否则回退到包大小之和
    totalSizeText: state.totalBytes != null ? fmtBytes(state.totalBytes) : fmtSize(totalSize),
    warnCount,
    cleanable,
    cleanableText: fmtSize(cleanable),
    todayUpdated,
    maxPkg,
    oldestPkg,
    top30: top30.map(p => ({
      ...p,
      heat: hasVisits
        ? Math.round(((p.visits || 0) / maxVisit) * 100)
        : Math.round((p.size / maxSize) * 100),
    })),
    top30By: hasVisits ? 'visits' : 'size',
  }
})

function fmtSize(mb) {
  if (mb >= 1024) return `${(mb / 1024).toFixed(1)} GB`
  return `${mb.toFixed(1)} MB`
}

/** 字节 → 可读文本 */
function fmtBytes(b) {
  const mb = b / 1024 / 1024
  if (mb >= 1024) return `${(mb / 1024).toFixed(1)} GB`
  return `${mb.toFixed(1)} MB`
}

const fmtSizeFn = fmtSize

async function refreshPackages(keyword = '') {
  const { packages, scannedAt, scanning, scanPackages, scanBytes, totalBytes } = await api.getPackages(keyword)
  state.packages = packages || []
  if (scannedAt) state.scannedAt = scannedAt
  if (scanPackages !== undefined) state.scanProgress.packages = scanPackages
  if (scanBytes !== undefined) state.scanProgress.bytes = scanBytes
  if (totalBytes !== undefined && totalBytes !== null) state.totalBytes = totalBytes
  return { scanning: !!scanning }
}

/** 轮询后端扫描进度，直到扫描完成 */
async function pollScanProgress() {
  for (;;) {
    await new Promise(r => setTimeout(r, 800))
    let p
    try {
      p = await api.getScanProgress()
    } catch {
      break // 接口异常时退出，避免遮罩永久拦截点击
    }
    state.scanProgress.packages = p.packages || 0
    state.scanProgress.bytes = p.bytes || 0
    if (!p.scanning) break
  }
}

/** 刷新数据：若后端仍在扫描则先轮询进度，扫完再拉取真实数据 */
async function doRefresh() {
  const first = await refreshPackages()
  if (first.scanning) {
    await pollScanProgress()
    await refreshPackages() // 扫描完成后重新拉取完整数据
  }
  await Promise.all([refreshThresholds(), refreshLogs()])
}

/** 手动重新扫描缓存目录（异步，遮罩实时显示进度） */
async function scanNow() {
  state.loading = true
  try {
    const res = await api.scanNow()
    if (!res.ok) return res
    await doRefresh()
    return res
  } finally {
    state.loading = false
  }
}

async function refreshThresholds() {
  const t = await api.getThresholds()
  state.threshold.versionThreshold = t.versionThreshold
  state.threshold.sizeThreshold = t.sizeThreshold
  state.threshold.exceptions = t.exceptions || []
}

async function refreshLogs() {
  state.logs = await api.getLogs()
}

async function refreshAll() {
  state.loading = true
  try {
    await doRefresh()
  } finally {
    state.loading = false
  }
}

async function saveThresholds(payload) {
  const ok = await api.saveThresholds(payload)
  if (ok) {
    await refreshThresholds()
    await refreshPackages()
  }
  return ok
}

async function ignorePkg(name) {
  await api.ignore(name)
  await refreshPackages()
}

async function unignorePkg(name) {
  await api.unignore(name)
  await refreshPackages()
}

async function cleanPkg(name, keep) {
  const res = await api.clean(name, keep)
  if (res.ok) {
    await Promise.all([refreshPackages(), refreshLogs()])
  }
  return res
}

async function deleteVersion(name, version) {
  const res = await api.deleteVersion(name, version)
  if (res.ok) {
    await Promise.all([refreshPackages(), refreshLogs()])
  }
  return res
}

export function useStore() {
  return {
    state,
    stats,
    fmtSize: fmtSizeFn,
    refreshAll,
    refreshPackages,
    refreshThresholds,
    refreshLogs,
    scanNow,
    saveThresholds,
    ignorePkg,
    unignorePkg,
    cleanPkg,
    deleteVersion,
  }
}