var fs = require('graceful-fs')
var path = require('path')
var _ = require('lodash')
var useragent = require('useragent')
var Promise = require('bluebird')

exports.browserFullNameToShort = function (fullName) {
  var agent = useragent.parse(fullName)
  var isKnown = agent.family !== 'Other' && agent.os.family !== 'Other'
  return isKnown ? agent.toAgent() + ' (' + agent.os + ')' : fullName
}

exports.isDefined = function (value) {
  return !_.isUndefined(value)
}

exports.isFunction = _.isFunction
exports.isString = _.isString
exports.isObject = _.isObject
exports.isArray = _.isArray

var ABS_URL = /^https?:\/\//
exports.isUrlAbsolute = function (url) {
  return ABS_URL.test(url)
}

exports.camelToSnake = function (camelCase) {
  return camelCase.replace(/[A-Z]/g, function (match, pos) {
    return (pos > 0 ? '_' : '') + match.toLowerCase()
  })
}

exports.ucFirst = function (word) {
  return word.charAt(0).toUpperCase() + word.substr(1)
}

exports.dashToCamel = function (dash) {
  var words = dash.split('-')
  return words.shift() + words.map(exports.ucFirst).join('')
}

exports.arrayRemove = function (collection, item) {
  var idx = collection.indexOf(item)

  if (idx !== -1) {
    collection.splice(idx, 1)
    return true
  }

  return false
}

exports.merge = function () {
  var args = Array.prototype.slice.call(arguments, 0)
  args.unshift({})
  return _.merge.apply({}, args)
}

exports.formatTimeInterval = function (time) {
  var mins = Math.floor(time / 60000)
  var secs = (time - mins * 60000) / 1000
  var str = secs + (secs === 1 ? ' sec' : ' secs')

  if (mins) {
    str = mins + (mins === 1 ? ' min ' : ' mins ') + str
  }

  return str
}

var replaceWinPath = function (path) {
  return exports.isDefined(path) ? path.replace(/\\/g, '/') : path
}

exports.normalizeWinPath = process.platform === 'win32' ? replaceWinPath : _.identity

exports.mkdirIfNotExists = function mkdir (directory, done) {
  // TODO(vojta): handle if it's a file
  /* eslint-disable handle-callback-err */
  fs.stat(directory, function (err, stat) {
    if (stat && stat.isDirectory()) {
      done()
    } else {
      mkdir(path.dirname(directory), function () {
        fs.mkdir(directory, done)
      })
    }
  })
  /* eslint-enable handle-callback-err */
}

exports.defer = function () {
  var resolve
  var reject
  var promise = new Promise(function () {
    resolve = arguments[0]
    reject = arguments[1]
  })

  return {
    resolve: resolve,
    reject: reject,
    promise: promise
  }
}

// export lodash
exports._ = _
