const { createWriteStream, createReadStream } = require('node:fs')
const { createHash } = require('node:crypto')
const { resolve, join } = require('node:path')
const { mkdir, readFile, rm } = require('node:fs/promises')
const { get } = require('node:https')
const { arch, type } = require('node:os')
const { pipeline } = require('node:stream')
const { createGunzip } = require('node:zlib')
const { extract } = require('tar-fs')
const { promisify } = require('node:util')

const pipelineAsync = promisify(pipeline)

const helmVersion = '3.12.1'
const hashmap = {
  darwin: {
    amd64: 'f487b5d8132bd2091378258a3029e33ee10f71575b2167cdfeaf6d0144d20938',
    arm64: 'e82e0433589b1b5170807d6fec75baedba40620458510bbd30cdb9d2246415fe',
  },
  linux: {
    amd64: '1a7074f58ef7190f74ce6db5db0b70e355a655e2013c4d5db2317e63fa9e3dea',
    arm64: '50548d4fedef9d8d01d1ed5a2dd5c849271d1017127417dc4c7ef6777ae68f7e',
  },
  windows: {
    amd64: '9040f8f37c90600a51db4934c04bc9c2adc058cb2161e20b5193b3ba46de10fa',
  },
}

function getExt(os) {
  if (os === 'windows') return '.zip'
  return 'tar.gz'
}

async function downloadHelmBinary(version, os, arch, downloadLocation) {
  console.log(
    `Downloading binary for version = ${version}, os = ${os}, arch = ${arch}, to download folder = ${downloadLocation}`,
  )
  const downloadUrl = `https://get.helm.sh/helm-v${version}-${os}-${arch}.${getExt(
    os,
  )}`
  const file = createWriteStream(join(downloadLocation, `helm.${getExt(os)}`))
  try {
    await new Promise((resolve, reject) => {
      try {
        get(downloadUrl, (resp) => {
          resp.pipe(file)
          file.on('finish', resolve)
          file.on('error', reject)
        })
      } catch (err) {
        reject(err)
      }
    })
  } finally {
    file.close()
  }
}

async function verifyHelmBinary(os, arch, downloadFolder) {
  const fileContents = await readFile(
    join(downloadFolder, `helm.${getExt(os)}`),
  )
  const hash = createHash('sha256').update(fileContents).digest('hex')
  return hash === hashmap[os][arch]
}

function getOsType() {
  const osType = type()
  return osType.split(' ')[0].split('_')[0].toLowerCase()
}

function getArch() {
  const archType = arch()
  switch (archType) {
    case 'x64':
      return 'amd64'
    default:
      return archType
  }
}

async function extractTar(downloadFolder, os) {
  if (os !== 'windows') {
    await pipelineAsync(
      createReadStream(join(downloadFolder, 'helm.tar.gz')),
      createGunzip(),
      extract(downloadFolder, {
        ignore(name) {
          if (name.endsWith('/')) return false
          if (name.endsWith('helm')) return false
          if (name.endsWith('.exe')) return false
          return true
        },
      }),
    )
  }
}

async function cleanUp(downloadFolder, os) {
  await rm(join(downloadFolder, `helm.${getExt(os)}`))
}

async function main() {
  console.log('Fetching helm binary')
  const binFolder = resolve('./bin')
  await mkdir(binFolder, {
    recursive: true,
  })
  const os = getOsType()
  const arch = getArch()
  await downloadHelmBinary(helmVersion, os, arch, binFolder)
  if (!(await verifyHelmBinary(os, arch, binFolder)))
    throw new Error('Binary integrity validation failed!')
  await extractTar(binFolder)
  await cleanUp(binFolder)
}

if (
  process.env.NODE_HELM_SKIP_DOWNLOAD != null &&
  process.env.NODE_HELM_SKIP_DOWNLOAD.toLowerCase() === 'true'
) {
  main().then(() => console.log('Finished Downloading Helm Binary'))
}