import fs from 'fs'
import path from 'path'
import os from 'os'

function matchObject(item, str) {
  return Object.prototype.toString.call(item)
    === '[object ' + str + ']'
}

function checkStat(name, fn) {
  try {
    return fn(name)
  } catch (err) {
    if (/^(ENOENT|EPERM|EACCES)$/.test(err.code)) {
      if (err.code !== 'ENOENT') {
        console.warn('Warning: Cannot access %s', name)
      }
      return false
    }
    throw err
  }
}

export function nil(item) {
  return item == null
}
export function array(item) {
  return Array.isArray(item)
}
export function emptyObject(item) {
  for (var key in item) {
    return false
  }
  return true
}
export function buffer(item) {
  return Buffer.isBuffer(item)
}
export function regExp(item) {
  return matchObject(item, 'RegExp')
}
export function string(item) {
  return matchObject(item, 'String')
}
export function func(item) {
  return typeof item === 'function'
}
export function number(item) {
  return matchObject(item, 'Number')
}
export function exists(name) {
  return fs.existsSync(name)
}
export function file(name) {
  return checkStat(name, function(n) {
    return fs.statSync(n).isFile()
  })
}
export function samePath(a, b) {
  return path.resolve(a) === path.resolve(b)
}
export function directory(name) {
  return checkStat(name, function(n) {
  return fs.statSync(n).isDirectory()
  })
}
export function symbolicLink(name) {
  return checkStat(name, function(n) {
  return fs.lstatSync(n).isSymbolicLink()
  })
}
export function windows() {
  return os.platform() === 'win32'
}