async function unpack(packager: PlatformPackager<any>, out: string, platform: string, options: InternalElectronDownloadOptions) {
  let dist: string | null | undefined = packager.config.electronDist
  if (dist != null) {
    const zipFile = `electron-v${options.version}-${platform}-${options.arch}.zip`
    const resolvedDist = path.resolve(packager.projectDir, dist)
    if ((await statOrNull(path.join(resolvedDist, zipFile))) != null) {
      options.cache = resolvedDist
      dist = null
    }
  }

  if (dist == null) {
    const zipPath = (await BluebirdPromise.all<any>([
      packager.info.electronDownloader(options),
      emptyDir(out)
    ]))[0]

    if (process.platform === "darwin" || isEnvTrue(process.env.USE_UNZIP)) {
      // on mac unzip faster than 7za (1.1 sec vs 1.6 see)
      await exec("unzip", ["-oqq", "-d", out, zipPath])
    }
    else {
      await spawn(path7za, debug7zArgs("x").concat(zipPath, "-aoa", `-o${out}`))
      if (platform === "linux") {
        // https://github.com/electron-userland/electron-builder/issues/786
        // fix dir permissions — opposite to extract-zip, 7za creates dir with no-access for other users, but dir must be readable for non-root users
        await BluebirdPromise.all([
          chmod(path.join(out, "locales"), "0755"),
          chmod(path.join(out, "resources"), "0755")
        ])
      }
    }
  }
  else {
    const source = packager.getElectronSrcDir(dist)
    const destination = packager.getElectronDestinationDir(out)
    log.info({source, destination}, "copying Electron")
    await emptyDir(out)
    await copyDir(source, destination, {
      isUseHardLink: DO_NOT_USE_HARD_LINKS,
    })
  }
}

export async function tar(compression: CompressionLevel | any | any, format: string, outFile: string, dirToArchive: string, isMacApp: boolean, tempDirManager: TmpDir): Promise<void> {
  const tarFile = await tempDirManager.getTempFile({suffix: ".tar"})
  const tarArgs = debug7zArgs("a")
  tarArgs.push(tarFile)
  tarArgs.push(path.basename(dirToArchive))

  await BluebirdPromise.all([
    exec(path7za, tarArgs, {cwd: path.dirname(dirToArchive)}),
    // remove file before - 7z doesn't overwrite file, but update
    unlinkIfExists(outFile),
  ])

  if (!isMacApp) {
    await exec(path7za, ["rn", tarFile, path.basename(dirToArchive), path.basename(outFile, `.${format}`)])
  }

  if (format === "tar.lz") {
    // noinspection SpellCheckingInspection
    let lzipPath = "lzip"
    if (process.platform === "darwin") {
      lzipPath = path.join(await getLinuxToolsPath(), "bin", lzipPath)
    }
    await exec(lzipPath, [compression === "store" ? "-1" : "-9", "--keep" /* keep (don't delete) input files */, tarFile])
    // bloody lzip creates file in the same dir where input file with postfix `.lz`, option --output doesn't work
    await move(`${tarFile}.lz`, outFile)
    return
  }

  const args = compute7zCompressArgs(format === "tar.xz" ? "xz" : (format === "tar.bz2" ? "bzip2" : "gzip"), {
    isRegularFile: true,
    method: "DEFAULT",
    compression,
  })
  args.push(outFile, tarFile)
  await exec(path7za, args, {
    cwd: path.dirname(dirToArchive),
  }, debug7z.enabled)
}

async function unpack(packager: PlatformPackager<any>, out: string, platform: string, options: InternalElectronDownloadOptions) {
  let dist: string | null | undefined = packager.config.electronDist
  if (dist != null) {
    const zipFile = `electron-v${options.version}-${platform}-${options.arch}.zip`
    const resolvedDist = path.resolve(packager.projectDir, dist)
    if ((await statOrNull(path.join(resolvedDist, zipFile))) != null) {
      options.cache = resolvedDist
      dist = null
    }
  }

  if (dist == null) {
    const zipPath = (await BluebirdPromise.all<any>([
      downloadElectron(options),
      emptyDir(out)
    ]))[0]

    await spawn(path7za, debug7zArgs("x").concat(zipPath, "-aoa", `-o${out}`))
  }
  else {
    const source = packager.getElectronSrcDir(dist)
    const destination = packager.getElectronDestinationDir(out)
    log(`Copying Electron from "${source}" to "${destination}"`)
    await emptyDir(out)
    await copyDir(source, destination, null, null, DO_NOT_USE_HARD_LINKS)
  }

  if (platform === "linux") {
    // https://github.com/electron-userland/electron-builder/issues/786
    // fix dir permissions — opposite to extract-zip, 7za creates dir with no-access for other users, but dir must be readable for non-root users
    await BluebirdPromise.all([
      chmod(path.join(out, "locales"), "0755"),
      chmod(path.join(out, "resources"), "0755")
    ])
  }
}

export function compute7zCompressArgs(format: string, options: ArchiveOptions = {}) {
  let storeOnly = options.compression === "store"
  const args = debug7zArgs("a")

  let isLevelSet = false
  if (process.env.ELECTRON_BUILDER_COMPRESSION_LEVEL != null) {
    storeOnly = false
    args.push(`-mx=${process.env.ELECTRON_BUILDER_COMPRESSION_LEVEL}`)
    isLevelSet = true
  }

  if (format === "zip" && options.compression === "maximum") {
    // http://superuser.com/a/742034
    args.push("-mfb=258", "-mpass=15")
  }

  if (!isLevelSet && !storeOnly) {
    args.push("-mx=9")
  }

  if (options.dictSize != null) {
    args.push(`-md=${options.dictSize}m`)
  }

  // https://sevenzip.osdn.jp/chm/cmdline/switches/method.htm#7Z
  // https://stackoverflow.com/questions/27136783/7zip-produces-different-output-from-identical-input
  // tc and ta are off by default, but to be sure, we explicitly set it to off
  // disable "Stores NTFS timestamps for files: Modification time, Creation time, Last access time." to produce the same archive for the same data
  if (!options.isRegularFile) {
    args.push("-mtc=off")
  }

  if (format === "7z" || format.endsWith(".7z")) {
    if (options.solid === false) {
      args.push("-ms=off")
    }

    if (options.isArchiveHeaderCompressed === false) {
      args.push("-mhc=off")
    }

    // args valid only for 7z
    // -mtm=off disable "Stores last Modified timestamps for files."
    args.push("-mtm=off", "-mta=off")
  }

  if (options.method != null) {
    if (options.method !== "DEFAULT") {
      args.push(`-mm=${options.method}`)
    }
  }
  else if (format === "zip" || storeOnly) {
    args.push(`-mm=${storeOnly ? "Copy" : "Deflate"}`)
  }

  if (format === "zip") {
    // -mcu switch:  7-Zip uses UTF-8, if there are non-ASCII symbols.
    // because default mode: 7-Zip uses UTF-8, if the local code page doesn't contain required symbols.
    // but archive should be the same regardless where produced
    args.push("-mcu")
  }
  return args
}