/**
 * 下载官方 EasyTier Windows x64 发行包并解压到 resources/easytier/
 * 须复制 exe 同目录下全部 DLL 等依赖，否则 easytier-core 会以 0xC0000135（3221225781）退出。
 * 设置 SKIP_EASYTIER=1 可跳过（CI 无网环境）
 */
import fs from 'fs'
import path from 'path'
import https from 'https'
import { fileURLToPath } from 'url'
import AdmZip from 'adm-zip'

const __dirname = path.dirname(fileURLToPath(import.meta.url))
const root = path.resolve(__dirname, '..')
const resDir = path.join(root, 'resources', 'easytier')
const DEFAULT_URL =
  process.env.EASYTIER_DOWNLOAD_URL ||
  'https://github.com/EasyTier/EasyTier/releases/download/v2.4.5/easytier-windows-x86_64-v2.4.5.zip'
const exeName = 'easytier-core.exe'
const bundleMarker = '.easytier_bundle_ok'

if (process.env.SKIP_EASYTIER === '1') {
  console.log('[easytier] SKIP_EASYTIER=1，跳过下载')
  process.exit(0)
}

function download(url) {
  return new Promise((resolve, reject) => {
    https
      .get(url, (res) => {
        if (res.statusCode >= 300 && res.statusCode < 400 && res.headers.location) {
          download(res.headers.location).then(resolve).catch(reject)
          return
        }
        if (res.statusCode !== 200) {
          reject(new Error(`HTTP ${res.statusCode} ${url}`))
          return
        }
        const chunks = []
        res.on('data', (c) => chunks.push(c))
        res.on('end', () => resolve(Buffer.concat(chunks)))
        res.on('error', reject)
      })
      .on('error', reject)
  })
}

function findExe(dir, name) {
  if (!fs.existsSync(dir)) return null
  for (const f of fs.readdirSync(dir, { withFileTypes: true })) {
    const p = path.join(dir, f.name)
    if (f.isDirectory()) {
      const r = findExe(p, name)
      if (r) return r
    } else if (f.name === name) {
      return p
    }
  }
  return null
}

fs.mkdirSync(resDir, { recursive: true })
const outExe = path.join(resDir, exeName)
const markerPath = path.join(resDir, bundleMarker)
if (fs.existsSync(outExe) && fs.existsSync(markerPath)) {
  console.log('[easytier] 已存在完整包，跳过:', outExe)
  process.exit(0)
}
if (fs.existsSync(outExe) && !fs.existsSync(markerPath)) {
  console.log('[easytier] 检测到旧版仅复制了 exe，将重新下载并解压全部依赖文件…')
}

console.log('[easytier] 下载:', DEFAULT_URL)
const buf = await download(DEFAULT_URL)
const zip = new AdmZip(buf)
const tmp = path.join(resDir, '_extract_tmp')
if (fs.existsSync(tmp)) fs.rmSync(tmp, { recursive: true })
fs.mkdirSync(tmp, { recursive: true })
zip.extractAllTo(tmp, true)
const found = findExe(tmp, exeName)
if (!found) {
  console.error('[easytier] zip 内未找到', exeName)
  process.exit(1)
}
const srcDir = path.dirname(found)
for (const name of fs.readdirSync(srcDir)) {
  const from = path.join(srcDir, name)
  const to = path.join(resDir, name)
  if (!fs.statSync(from).isFile()) continue
  fs.copyFileSync(from, to)
}
fs.rmSync(tmp, { recursive: true })
fs.writeFileSync(
  path.join(resDir, 'NOTICE-EasyTier.txt'),
  [
    'EasyTier 以 LGPL-3.0 授权发布。',
    '源码: https://github.com/EasyTier/EasyTier',
    '本程序随官方 GitHub Release 附带 easytier-core.exe 及同目录依赖，未修改二进制。',
    '',
  ].join('\n'),
  'utf-8',
)
fs.writeFileSync(markerPath, `${new Date().toISOString()}\n`, 'utf-8')
console.log('[easytier] 完成（已复制 zip 内同目录全部文件）:', outExe)