var _ = require('lodash')
var supportedLanguages = require('./../../../common/lang/langs.json')

module.exports = function (SettingsService, $q, gettextCatalog) {
  var LanguageService = {}

  LanguageService.supportedLanguages = supportedLanguages

  var browserLocale = navigator.language || navigator.userLanguage || 'en-US'
  var browserLanguage = browserLocale.substring(0, 2)
  var isLanguageMatched = _.some(supportedLanguages, function (value, key) {
    return key === browserLanguage
  })
  var detectedLanguage = isLanguageMatched ? browserLanguage : 'en'

  var defaultLanguage = 'ja'
  LanguageService.detectedLanguage = defaultLanguage
  LanguageService.selectedLanguage = null

  // TODO: Can't this be refactored to something like this?
  //  SettingsService.sync(LanguageService.selectedLanguage, 'Language', {
  //    selected: LanguageService.detectedLanguage
  //  })

  LanguageService.getSelectedLanguage = function () {
    var deferred = $q.defer()
    if (LanguageService.selectedLanguage) {
      deferred.resolve(LanguageService.selectedLanguage)
    } else {
      SettingsService.getItem('Language.selected').then(function (data) {
        if (data) {
          deferred.resolve(data)
        } else {
          LanguageService.setSelectedLanguage(LanguageService.detectedLanguage)
            .then(function () {
              deferred.resolve(LanguageService.detectedLanguage)
            })
        }
      })
    }
    return deferred.promise
  }

  // TODO: this is to prevent initial text flashing from ja
  gettextCatalog.currentLanguage = LanguageService.detectedLanguage

  // Initialize gettextCatalog

  LanguageService.init = function () {
    LanguageService.getSelectedLanguage().then(function (data) {
      LanguageService.setSelectedLanguage(data)
    })
  }


  LanguageService.setSelectedLanguage = function (lang) {
    var deferred = $q.defer()
    LanguageService.selectedLanguage = lang
    gettextCatalog.currentLanguage = lang
    SettingsService.setItem('Language.selected', lang).then(function () {
      deferred.resolve(lang)
    })
    return deferred.promise
  }

  return LanguageService
}