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

import { Observable, forkJoin } from 'rxjs';

import { environment, CLIENT_ID } from '../../environments/environment';

const baseUrls = environment.baseUrls;
const ACCESS_TOKEN_STORAGE_KEY = 'accessToken';
const REFRESH_TOKEN_STORAGE_KEY = 'refreshToken';
const PUBLIC_CERTIFICATE_KEY = 'publicCertificate';
const PUBLIC_CERTIFICATE_ALG = 'publicCertificateAlg';

export class AuthResponse {
  email: string;
  access_token: string;
  refresh_token?: string;
}

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

@Injectable()
export class AuthService {
  constructor(private http: HttpClient) {}

  private SERVICE_URL = `${baseUrls.serviceSecurity}/oauth/token`;
  private PUBLIC_CERTIFICATE_URL = `${baseUrls.serviceSecurity}/oauth/token_key`;

  /**
   * Authenticate user
   * @param username
   * @param password
   * @param clientId
   * @param accessId
   */
  private _authenticate(
    username: string,
    password: string,
    clientId: string,
    accessId: string = ''
  ): Observable<AuthResponse> {
    const body = new HttpParams()
      .set('grant_type', 'password')
      .set('username', username)
      .set('password', password)
      .set('client_id', clientId)
      .set('access_id', accessId);

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

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

  /**
   * Login and authenticate user with Client ID then set api token on success
   * @param email
   * @param password
   */
  public login(username: string, password: string) {
    const authenticate$ = this._authenticate(
      username.toLocaleLowerCase().trim(),
      password,
      CLIENT_ID
    );
    const certificate$ = this.http.get<PublicCertificate>(
      this.PUBLIC_CERTIFICATE_URL
    );

    return forkJoin(certificate$, authenticate$).pipe(
      tap(([certificate, authenticate]) => {
        localStorage.setItem('email', authenticate.email);
        localStorage.setItem(
          ACCESS_TOKEN_STORAGE_KEY,
          authenticate.access_token
        );
        localStorage.setItem(
          REFRESH_TOKEN_STORAGE_KEY,
          authenticate.refresh_token
        );
        localStorage.setItem(PUBLIC_CERTIFICATE_KEY, certificate.value);
        localStorage.setItem(PUBLIC_CERTIFICATE_ALG, certificate.alg);
      }),
      shareReplay()
    );
  }
}