module.exports = which which.sync = whichSync

var isWindows = process.platform === 'win32' ||

process.env.OSTYPE === 'cygwin' ||
process.env.OSTYPE === 'msys'

var path = require('path') var COLON = isWindows ? ';' : ':' var isexe = require('isexe')

function getNotFoundError (cmd) {

var er = new Error('not found: ' + cmd)
er.code = 'ENOENT'

return er

}

function getPathInfo (cmd, opt) {

var colon = opt.colon || COLON
var pathEnv = opt.path || process.env.PATH || ''
var pathExt = ['']

pathEnv = pathEnv.split(colon)

var pathExtExe = ''
if (isWindows) {
  pathEnv.unshift(process.cwd())
  pathExtExe = (opt.pathExt || process.env.PATHEXT || '.EXE;.CMD;.BAT;.COM')
  pathExt = pathExtExe.split(colon)

  // Always test the cmd itself first.  isexe will check to make sure
  // it's found in the pathExt set.
  if (cmd.indexOf('.') !== -1 && pathExt[0] !== '')
    pathExt.unshift('')
}

// If it has a slash, then we don't bother searching the pathenv.
// just check the file itself, and that's it.
if (cmd.match(/\//) || isWindows && cmd.match(/\\/))
  pathEnv = ['']

return {
  env: pathEnv,
  ext: pathExt,
  extExe: pathExtExe
}

}

function which (cmd, opt, cb) {

if (typeof opt === 'function') {
  cb = opt
  opt = {}
}

var info = getPathInfo(cmd, opt)
var pathEnv = info.env
var pathExt = info.ext
var pathExtExe = info.extExe
var found = []

;(function F (i, l) {
  if (i === l) {
    if (opt.all && found.length)
      return cb(null, found)
    else
      return cb(getNotFoundError(cmd))
  }

  var pathPart = pathEnv[i]
  if (pathPart.charAt(0) === '"' && pathPart.slice(-1) === '"')
    pathPart = pathPart.slice(1, -1)

  var p = path.join(pathPart, cmd)
  if (!pathPart && (/^\.[\\\/]/).test(cmd)) {
    p = cmd.slice(0, 2) + p
  }
  ;(function E (ii, ll) {
    if (ii === ll) return F(i + 1, l)
    var ext = pathExt[ii]
    isexe(p + ext, { pathExt: pathExtExe }, function (er, is) {
      if (!er && is) {
        if (opt.all)
          found.push(p + ext)
        else
          return cb(null, p + ext)
      }
      return E(ii + 1, ll)
    })
  })(0, pathExt.length)
})(0, pathEnv.length)

}

function whichSync (cmd, opt) {

opt = opt || {}

var info = getPathInfo(cmd, opt)
var pathEnv = info.env
var pathExt = info.ext
var pathExtExe = info.extExe
var found = []

for (var i = 0, l = pathEnv.length; i < l; i ++) {
  var pathPart = pathEnv[i]
  if (pathPart.charAt(0) === '"' && pathPart.slice(-1) === '"')
    pathPart = pathPart.slice(1, -1)

  var p = path.join(pathPart, cmd)
  if (!pathPart && /^\.[\\\/]/.test(cmd)) {
    p = cmd.slice(0, 2) + p
  }
  for (var j = 0, ll = pathExt.length; j < ll; j ++) {
    var cur = p + pathExt[j]
    var is
    try {
      is = isexe.sync(cur, { pathExt: pathExtExe })
      if (is) {
        if (opt.all)
          found.push(cur)
        else
          return cur
      }
    } catch (ex) {}
  }
}

if (opt.all && found.length)
  return found

if (opt.nothrow)
  return null

throw getNotFoundError(cmd)

}