config.js

const URL = require('url')
const path = require('path')
const os = require('os')
const fs = require('fs')

const embeddedGit = require('./embedded-git.json')

function getConfig() {
  const config = {
    outputPath: path.join(__dirname, '..', 'git', 'default'),
    source: '',
    checksum: '',
    fileName: '',
    tempFile: '',
  }

  // Possible values are ‘x64’, ‘arm’, ‘arm64’, ‘s390’, ‘s390x’, ‘mipsel’, ‘ia32’, ‘mips’, ‘ppc’ and ‘ppc64’
  let arch = os.arch()

  if (process.env.npm_config_arch) {
    // If a specific npm_config_arch is set, we use that one instead of the OS arch (to support cross compilation)
    console.log('npm_config_arch detected: ' + process.env.npm_config_arch)
    arch = process.env.npm_config_arch
  }

  if (process.platform === 'win32' && arch === 'arm64') {
    // Use the Dugite Native ia32 package for Windows arm64 (arm64 can run 32-bit code through emulation)
    console.log('Downloading 32-bit Dugite Native for Windows arm64')
    arch = 'ia32'
  }

  const key = `${process.platform}-${arch}`

  const entry = embeddedGit[key]

  if (entry != null) {
    config.checksum = entry.checksum
    config.source = entry.url
  } else {
    console.log(
      `No embedded Git found for ${process.platform} and architecture ${arch}`
    )
  }

  if (config.source !== '') {
    processConfig(config)
  }

  if (process.platform === 'win32') {
    const entry = embeddedGit['linux-x64']

    const wslConfig = {
      outputPath: path.join(__dirname, '..', 'git', 'linux-x64'),
      source: entry.url,
      checksum: entry.checksum,
      fileName: '',
      tempFile: '',
    }

    processConfig(wslConfig)

    return [config, wslConfig]
  }

  return [config]
}

function processConfig(config) {
  // compute the filename from the download source
  const url = URL.parse(config.source)
  const pathName = url.pathname
  const index = pathName.lastIndexOf('/')
  config.fileName = pathName.substr(index + 1)

  const cacheDirEnv = process.env.DUGITE_CACHE_DIR

  const cacheDir = cacheDirEnv ? path.resolve(cacheDirEnv) : os.tmpdir()

  try {
    fs.statSync(cacheDir)
  } catch (e) {
    fs.mkdirSync(cacheDir)
  }

  config.tempFile = path.join(cacheDir, config.fileName)
}

module.exports = getConfig