import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';

import { Observable } from 'rxjs/Observable';
import { BehaviorSubject } from 'rxjs/BehaviorSubject';

import { CookieService } from 'ngx-cookie-service';
import {environment} from '../environments/environment';

import { IdP, AuthInfo } from './types/types.module';

@Injectable({
  providedIn: 'root'
})
export class IdpService {

  idps: IdP[];
  idps$: BehaviorSubject<IdP[]>;

  selectedIdp: IdP;
  selectedIdp$: BehaviorSubject<IdP>;

  constructor(
    public http: HttpClient,
    public cookieService: CookieService,
  ) {
    this.initializeDataService();
  }

  private initializeDataService() {
    if (!this.idps$) {
      this.idps$ = <BehaviorSubject<IdP[]>> new BehaviorSubject(new Array<IdP>());
    }
    if (!this.selectedIdp$) {
      this.selectedIdp$ = <BehaviorSubject<IdP>> new BehaviorSubject(new Object);
    }
    this.apiCall();
  }

  private apiCall(): void {
      // initialize the subject with data
      this.http.get('/backend/auth/v1/info').subscribe(
        (info: AuthInfo) => {
          this.idps = info.idps;
          this.idps$.next(this.idps);

          let preferredIdP: IdP = this.idps.find((idp: IdP) => idp.id === this.getIdPPreference());
          let defaultIdP: IdP = this.idps.find((idp: IdP) => idp.id === info.default);

          if (preferredIdP) {
            this.selectedIdp = preferredIdP;
          } else if (defaultIdP) {
            this.selectedIdp = defaultIdP;
          } else if (this.idps.length > 0) {
            this.selectedIdp = this.idps[0];
          } else {
            console.log("No IdPs available. Unable to login");
          }

          this.selectedIdp$.next(this.selectedIdp);
        }
      );

  }

  private getIdPPreference(): number {
    return Number(this.cookieService.get(environment.idpCookieName));
  }

  public subscribeIdps(): Observable<IdP[]> {
    return this.idps$.asObservable();
  }

  public subscribeSelectedIdp(): Observable<IdP> {
    return this.selectedIdp$.asObservable();
  }

  public setIdPPreference(idp: IdP) {
    this.cookieService.set(environment.idpCookieName, String(idp.id));
  }
}