import { HttpClient } from '@angular/common/http';
import { TranslateLoader } from '@ngx-translate/core';
import { forkJoin, Observable } from 'rxjs';
import { map } from 'rxjs/operators';

export class MultiTranslateHttpLoader implements TranslateLoader {
  constructor(
    private http: HttpClient,
    public resources: { prefix: string; suffix: string }[] = [
      {
        prefix: './assets/i18n/',
        suffix: '.json'
      }
    ]
  ) {}

  public getTranslation(lang: string): Observable<unknown> {
    return forkJoin(
      this.resources.map((config) => {
        return this.http.get(`${config.prefix}${lang}${config.suffix}`);
      })
    ).pipe(
      map((response) => {
        return response.reduce((a, b) => {
          return Object.assign(a, b);
        });
      })
    );
  }
}