const crypto = require('crypto')
const fs = require('fs')
const path = require('path')

const CONFIG = require('../config')
const FINGERPRINT_PATH = path.join(CONFIG.repositoryRootPath, 'node_modules', '.dependencies-fingerprint')

module.exports = {
  write: function () {
    const fingerprint = this.compute()
    fs.writeFileSync(FINGERPRINT_PATH, fingerprint)
    console.log('Wrote Dependencies Fingerprint:', FINGERPRINT_PATH, fingerprint)
  },
  read: function () {
    return fs.existsSync(FINGERPRINT_PATH) ? fs.readFileSync(FINGERPRINT_PATH, 'utf8') : null
  },
  isOutdated: function () {
    const fingerprint = this.read()
    return fingerprint ? fingerprint !== this.compute() : false
  },
  compute: function () {
    // Include the electron minor version in the fingerprint since that changing requires a re-install
    const electronVersion = CONFIG.appMetadata.electronVersion.replace(/\.\d+$/, '')
    const apmVersion = CONFIG.apmMetadata.dependencies['atom-package-manager']
    const body = electronVersion + apmVersion + process.platform + process.version + process.arch
    return crypto.createHash('sha1').update(body).digest('hex')
  }
}