'use strict'
  const chalk = require('chalk')
  const semver = require('semver')
  const packageConfig = require('../package.json')
  const shell = require('shelljs')
  
  function exec (cmd) {
    return require('child_process').execSync(cmd).toString().trim()
  }
  
  const versionRequirements = [
    {
      name: 'node',
      currentVersion: semver.clean(process.version),
      versionRequirement: packageConfig.engines.node
    }
  ]
  
  if (shell.which('npm')) {
    versionRequirements.push({
      name: 'npm',
      currentVersion: exec('npm --version'),
      versionRequirement: packageConfig.engines.npm
    })
  }
  
  module.exports = function () {
    const warnings = []
  
    for (let i = 0; i < versionRequirements.length; i++) {
      const mod = versionRequirements[i]
  
      if (!semver.satisfies(mod.currentVersion, mod.versionRequirement)) {
        warnings.push(mod.name + ': ' +
          chalk.red(mod.currentVersion) + ' should be ' +
          chalk.green(mod.versionRequirement)
        )
      }
    }
  
    if (warnings.length) {
      console.log('')
      console.log(chalk.yellow('To use this template, you must update following to modules:'))
      console.log()
  
      for (let i = 0; i < warnings.length; i++) {
        const warning = warnings[i]
        console.log('  ' + warning)
      }
  
      console.log()
      process.exit(1)
    }
  }