// Angular
import { Injectable, EventEmitter } from '@angular/core';
import { registerLocaleData } from '@angular/common';
import localeNb from '@angular/common/locales/nb';
import localeLt from '@angular/common/locales/lt';
import localePl from '@angular/common/locales/pl';
import localeEnGb from '@angular/common/locales/en-GB';
import { TranslateService, LangChangeEvent } from '@ngx-translate/core';
import * as moment from 'moment';

export const Languages = ['en', 'no', 'lt', 'pl'];

@Injectable()
export class MwLocaleService {
  onLocaleChanged = new EventEmitter<string>();

  private currentLocale = 'en-GB';
  constructor(private translateService: TranslateService) {
    this.onLangChanged(translateService.currentLang);
    this.translateService.onLangChange.subscribe((event: LangChangeEvent) =>
      this.onLangChanged(event.lang)
    );
  }

  registerLocales(): void {
    registerLocaleData(localeNb, 'nb');
    registerLocaleData(localeLt, 'lt');
    registerLocaleData(localePl, 'pl');
    registerLocaleData(localeEnGb, 'en-GB');
  }

  langToLocale(langCode: string): string {
    let locale = 'en-GB';

    switch (langCode) {
      case 'pl':
        locale = 'pl';
        break;
      case 'lt':
        locale = 'lt';
        break;
      case 'no':
        locale = 'nb';
        break;
      case 'en':
        locale = 'en-GB';
    }

    return locale;
  }

  private onLangChanged(lang: string): void {
    this.currentLocale = this.langToLocale(lang);
    this.handleMomentLocale(lang);
    this.onLocaleChanged.emit(this.currentLocale);
  }

  private handleMomentLocale(lang: any): void {
    let momentLocale = lang;

    if (momentLocale === 'no') {
      momentLocale = 'nb';
    }

    if (momentLocale === 'en') {
      momentLocale = 'en-gb';
    }

    moment.locale(momentLocale);
  }

  public toString: () => string = () => {
    return this.currentLocale;
  };

  public toLowerCase: () => string = () => {
    return this.currentLocale.toLowerCase();
  };
}