import { shareReplay, tap } from 'rxjs/operators';
import { Injectable } from '@angular/core';
import { HttpClient, HttpParams, HttpHeaders } from '@angular/common/http';

import { Observable, of, Observer } from 'rxjs';

import { AuthTokenService } from './auth-token.service';
import { ConfigService } from '@arrow/bom/config';

export interface IPublicCertificate {
  alg: string;
  value: string;
}

export interface IAuthResult {
  access_token: string;
  token_type?: string;
  refresh_token?: string;
  expires_in?: number;
}

@Injectable()
export class AuthService {
  constructor(
    private http: HttpClient,
    private authTokenService: AuthTokenService,
    private config: ConfigService
  ) {}

  private SERVICE_URL = `${this.config.getSecurityApi()}/oauth/token`;

  private _requestNewTokens(refreshToken): Observable<any> {
    const body = new HttpParams()
      .set('grant_type', 'refresh_token')
      .set('refresh_token', refreshToken)
      .set('client_id', this.authTokenService.getClientId());

    const headers = new HttpHeaders().set(
      'Content-Type',
      'application/x-www-form-urlencoded'
    );

    return this.http.post(this.SERVICE_URL, body, { headers });
  }

  /**
   * Request and Store the new access and refresh token in local storage
   */
  private _requestAndSetTokensInLocalStorage(refreshToken: string) {
    return this._requestNewTokens(refreshToken).pipe(
      tap(newTokens => {
        this.authTokenService.setTokens(newTokens);
        return newTokens;
      }),
      shareReplay()
    );
  }

  public checkAndRenewTokens(): Observable<any> {
    const accessToken = this.authTokenService.getValidAccessToken();
    const refreshToken = this.authTokenService.getValidRefreshToken();

    if (accessToken) return of({ access_token: accessToken });
    if (!accessToken && refreshToken)
      return this._requestAndSetTokensInLocalStorage(refreshToken);

    return new Observable((observer: Observer<any>) => {
      observer.error(new Error('Both access and refresh tokens are not valid'));
      observer.complete();
    });
  }
}