'use strict'

const os = require('os')
const url = require('url')
const path = require('path')
const cp = require('child_process')
const fs = require('fs-extra')
const request = require('request')
const extractZip = require('extract-zip')

const PHANTOM_VERSION = '2.1.1'
const DEFAULT_CDN = 'https://github.com/Medium/phantomjs/releases/download/v2.1.1'
const ARM_URL = 'https://github.com/fg2it/phantomjs-on-raspberry/raw/master/rpi-1-2-3/wheezy-jessie/v2.1.1/phantomjs'
const PLATFORM = os.platform()
const ARCH = os.arch()

const getDownloadUrl = () => {
  let downloadUrl = DEFAULT_CDN + '/phantomjs-' + PHANTOM_VERSION + '-'
  if (PLATFORM === 'linux' && ARCH === 'x64') {
    downloadUrl += 'linux-x86_64.tar.bz2'
  } else if (PLATFORM === 'linux' && ARCH == 'ia32') {
    downloadUrl += 'linux-i686.tar.bz2'
  } else if (PLATFORM === 'linux' && ARCH.search('arm') !== -1) {
    downloadUrl = ARM_URL  
  } else if (PLATFORM === 'darwin') {
    downloadUrl += 'macosx.zip'
  } else if (PLATFORM === 'win32') {
    downloadUrl += 'windows.zip'
  } else {
    return null
  }
  return downloadUrl
}

const downloadPhantomjs = (logger, downloadUrl, data_dir) => {
  return new Promise((resolve, reject) => {
    const file_name = downloadUrl.split('/').pop()
    const downloaded_file = path.join(data_dir, file_name)
    // actually downloads the file
    const startDownload = (url, dest, cb) => { 
      const file = fs.createWriteStream(dest)
      // download file
      request(url)
        .pipe(file)
        .on('error', cb)

        file.on('close', () => {
          // close file & invoke callback
          file.close()
          cb()
        })
    }
    startDownload(downloadUrl, downloaded_file, err => {
      if (err) return reject(err)
      resolve(downloaded_file)
    })
  })
}

const extractDownload = (logger, filePath) => {
  return new Promise((resolve, reject) => {
    var extractedPath = filePath + '-extract-' + Date.now()
    var options = {cwd: extractedPath}
    fs.mkdirsSync(extractedPath, '0777')
    // Make double sure we have 0777 permissions; some operating systems
    // default umask does not allow write by default.
    fs.chmodSync(extractedPath, '0777')
    if (filePath.substr(-4) === '.zip') {
      logger.log('PHANTOMJS','Extracting zip contents')
      extractZip(path.resolve(filePath), {dir: extractedPath}, err => {
        if (err) {
          reject(err)
        } else {
          resolve(extractedPath)
        }
      })
    } else {
      logger.log('PHANTOMJS', 'Extracting tar contents (via spawned process)')
      cp.execFile('tar', ['jxf', path.resolve(filePath)], options, err => {
        if (err) {
          reject(err)
        } else {
          resolve(extractedPath)
        }
      })
    }
  })
}

const copyIntoPlace = (logger, extractedPath, archiveFile, targetPath) => {
  return new Promise((resolve, reject) => {
    logger.log('PHANTOMJS', `Removing ${archiveFile}`)
    fs.removeSync(archiveFile)
    const folders = fs.readdirSync(extractedPath)
    const bin_dir = path.join(extractedPath, folders[0], 'bin')
    const files = fs.readdirSync(path.join(extractedPath, folders[0], 'bin'))
    let moved = false
    for (let i = 0; i < files.length; i++) {
      let file = path.join(bin_dir, files[i])
      let filename = files[i]
      let target = targetPath + path.sep + filename
      logger.log('PHANTOMJS', `Copying extracted binary ${file} -> ${target}`)
      fs.moveSync(file, target)
      logger.log('PHANTOMJS', `Removing temporary download folder ${extractedPath}`)      
      fs.removeSync(extractedPath)
      moved = target
    }

    if (moved !== false) {
      resolve(moved)
    } else {
      reject()
    }
  })
}

const download = async (logger, phantom_bin, data_dir) => {
  const download_url = getDownloadUrl()
  let downloaded_file = ''
  let extracted_folder = ''
  let moved_file = ''
  // error out if we couldn't find a suitable platform/arch combination
  if (download_url === null) {
    logger.log('ERROR',
          `Unexpected platform or architecture: ${PLATFORM} / ${ARCH}\n` +
          'It seems there is no binary available for your platform/architecture\n' +
          `Try to install PhantomJS on your own & copy/link the executable to "${data_dir}"`)
    return false
  }
  logger.log('PHANTOMJS', `Downloading from "${download_url}" to "${data_dir}/"`)

  // download phantomjs
  try {
    downloaded_file = await downloadPhantomjs(logger, download_url, data_dir)
    logger.log('PHANTOMJS', 'Download finished')
  } catch (e) {
    logger.log('ERROR', 'Error downloading PhantomJS - ' + e)
    return false
  }

  // extract phantomjs (if needed)
  // if it´s ARM, we´re done now
  if (ARCH.search('arm') !== -1) return true
  logger.log('PHANTOMJS', `Extracting PhantomJS binary: ${downloaded_file}`)
  try {
    extracted_folder = await extractDownload(logger, downloaded_file)
  } catch (e) {
    logger.log('ERROR', 'Error extracting PhantomJS - ' + e)
    return false
  }

  logger.log('PHANTOMJS', 'Successfully extracted archive: "${extracted_folder}"')

  // move Phantom executable
  logger.log('PHANTOMJS', 'Moving executable to top level')
  try {
    moved_file = await copyIntoPlace(logger, extracted_folder, downloaded_file, data_dir)
  } catch (e) {
    logger.log('PHANTOMJS', 'Could not find extracted file')
    return false
  }

  // make phantomjs executable
  try {
    fs.chmodSync(moved_file, '755')
  } catch (e) {
    logger.log('PHANTOMJS', 'Possible error with rights of downloaded Phantom binary')    
  }

  return true
}

module.exports = (logger) => {
  return {
    download: download.bind(this, logger)
  }
}