/**
  @module ember-flexberry
*/

import { typeOf, isBlank, isNone } from '@ember/utils';
import { warn } from '@ember/debug';

/**
  Configures a <a href="https://github.com/jamesarosen/ember-i18n">i18n service</a> for current application instance.
  Sets browser's current locale to <a href="https://github.com/jamesarosen/ember-i18n/wiki/Doc:-Setting-the-Locale">i18n.locale</a> property.

  @for ApplicationInstanceInitializer
  @method i18n.initialize
  @param {<a href="https://www.emberjs.com/api/ember/release/classes/ApplicationInstance">ApplicationInstance</a>} applicationInstance Ember application instance.
*/
export function initialize(applicationInstance) {
  let i18n = applicationInstance.lookup('service:i18n');
  if (isNone(i18n)) {
    return;
  }

  let ENV = applicationInstance.factoryFor('config:environment').class;
  let defaultLocale = (ENV.i18n || {}).defaultLocale;
  let currentLocale = defaultLocale;

  // If no default locale is set...
  if (isBlank(defaultLocale)) {
    // ...then trying to get locale from browser settings.
    // See https://alicoding.com/detect-browser-language-preference-in-firefox-and-chrome-using-javascript
    currentLocale = navigator.languages ? navigator.languages[0] : (navigator.language || navigator.userLanguage);
    let indexOfDash = currentLocale.indexOf('-');
    if (!isBlank(currentLocale) && indexOfDash > -1) {
      currentLocale = currentLocale.substr(0, indexOfDash);
    }
  }

  // Check if current locale is supported.
  let locales = applicationInstance.lookup('controller:application').get('locales');
  if (!locales || typeOf(locales) !== 'array' || locales.indexOf(currentLocale) === -1 || isBlank(currentLocale)) {
    warn('Default locale from `environment.js` or current browser language is not supported. Using "en" as default locale.',
    false,
    { id: 'ember-flexberry-debug.i18n.locale-is-not-supported' });
    currentLocale = 'en';
  }

  let i18nLocale = i18n.get('locale');
  if (currentLocale !== i18nLocale) {
    i18n.set('locale', currentLocale);
  }
}

export default {
  name: 'i18n',
  initialize
};