'use strict'
  
  var jsonSafeStringify = require('json-stringify-safe')
    , crypto = require('crypto')
    , Buffer = require('safe-buffer').Buffer
  
  var defer = typeof setImmediate === 'undefined'
    ? process.nextTick
    : setImmediate
  
  function paramsHaveRequestBody(params) {
    return (
      params.body ||
      params.requestBodyStream ||
      (params.json && typeof params.json !== 'boolean') ||
      params.multipart
    )
  }
  
  function safeStringify (obj, replacer) {
    var ret
    try {
      ret = JSON.stringify(obj, replacer)
    } catch (e) {
      ret = jsonSafeStringify(obj, replacer)
    }
    return ret
  }
  
  function md5 (str) {
    return crypto.createHash('md5').update(str).digest('hex')
  }
  
  function isReadStream (rs) {
    return rs.readable && rs.path && rs.mode
  }
  
  function toBase64 (str) {
    return Buffer.from(str || '', 'utf8').toString('base64')
  }
  
  function copy (obj) {
    var o = {}
    Object.keys(obj).forEach(function (i) {
      o[i] = obj[i]
    })
    return o
  }
  
  function version () {
    var numbers = process.version.replace('v', '').split('.')
    return {
      major: parseInt(numbers[0], 10),
      minor: parseInt(numbers[1], 10),
      patch: parseInt(numbers[2], 10)
    }
  }
  
  exports.paramsHaveRequestBody = paramsHaveRequestBody
  exports.safeStringify         = safeStringify
  exports.md5                   = md5
  exports.isReadStream          = isReadStream
  exports.toBase64              = toBase64
  exports.copy                  = copy
  exports.version               = version
  exports.defer                 = defer