@Injectable()
export class UserService {
  private currentUserSubject = new BehaviorSubject<User>({} as User);
  public currentUser = this.currentUserSubject.asObservable().pipe(distinctUntilChanged());

  private isAuthenticatedSubject = new ReplaySubject<boolean>(1);
  public isAuthenticated = this.isAuthenticatedSubject.asObservable();

  constructor(
    @Inject(LOCAL_STORAGE) private localStorage: any,
    private apiService: ApiService,
    private jwtService: JwtService
  ) {
    this.populate();
  }

  // Verify JWT in localstorage with server & load user's info.
  // This runs once on application startup.
  private populate() {
    // If JWT detected, attempt to get & store user's info
    if (this.jwtService.getToken()) {
      this.apiService.get('Accounts/Info')
      .subscribe(
        data => this.setUser(data),
        err => this.purgeAuth()
      );
    } else {
      // Remove any potential remnants of previous auth states
      this.purgeAuth();
    }
  }

  setUser(user: User) {
    // console.log(user);
    // // Save JWT sent from server in localstorage
    // this.jwtService.saveToken(user.access_token);
    // Set current user data into observable
    this.currentUserSubject.next(user);
    // Set isAuthenticated to true
    this.isAuthenticatedSubject.next(true);
  }

  purgeAuth() {
    // Remove JWT from localstorage
    this.jwtService.destroyToken();
    // wipe all localstorage data
    this.localStorage.clear();
    // Set current user to an empty object
    this.currentUserSubject.next(null as User);
    // Set auth status to false
    this.isAuthenticatedSubject.next(false);
  }

  attemptRegister(credentials: IRegisterUser) {
    return this.apiService.post('Accounts/Register', credentials);
  }

  attemptAuth(credentials: ILoginUser): Observable<User> {
    // Convert json to form values instead
    const formValues = {
      grant_type: credentials.grant_type,
      username: credentials.Email,
      password: credentials.Password,
    };

    return this.apiService.post('Accounts/Login', formValues)
      .pipe(map(
      (data) => {
        this.jwtService.saveToken(data.access_token);
        this.isAuthenticatedSubject.next(true);
        this.populate();
        return data;
      }
    ));
  }

  getCurrentUser(): User {
    return this.currentUserSubject.value;
  }
}