'use strict'

var jsonSafeStringify = require('json-stringify-safe')
  , crypto = require('crypto')

function deferMethod() {
  if (typeof setImmediate === 'undefined') {
    return process.nextTick
  }

  return setImmediate
}

function isFunction(value) {
  return typeof value === 'function'
}

function paramsHaveRequestBody(params) {
  return (
    params.body ||
    params.requestBodyStream ||
    (params.json && typeof params.json !== 'boolean') ||
    params.multipart
  )
}

function safeStringify (obj) {
  var ret
  try {
    ret = JSON.stringify(obj)
  } catch (e) {
    ret = jsonSafeStringify(obj)
  }
  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 (new Buffer(str || '', 'utf8')).toString('base64')
}

exports.isFunction            = isFunction
exports.paramsHaveRequestBody = paramsHaveRequestBody
exports.safeStringify         = safeStringify
exports.md5                   = md5
exports.isReadStream          = isReadStream
exports.toBase64              = toBase64
exports.defer                 = deferMethod()