@Injectable()
export class AuthService {
  authIsLoading = new BehaviorSubject<boolean>(false);
  authDidFail = new BehaviorSubject<boolean>(false);
  authStatusChanged = new Subject<boolean>();
  registeredUser: CognitoUser;
  constructor(private router: Router) {}
  
  signUp(username: string, email: string, password: string): void {
    this.authIsLoading.next(true);
    const user: User = {
      username: username,
      email: email,
      password: password
    };
    
    const attributeList: CognitoUserAttribute[] = [];
    const emailAttribute = {
      Name: 'email',
      Value: user.email
    };
    attributeList.push(new CognitoUserAttribute(emailAttribute));
    
    userPool.signUp(user.username, user.password, attributeList, null, (err, result) =>{
      if (err) {
        this.authDidFail.next(true);
        this.authIsLoading.next(false);
        return;
      }
      this.authDidFail.next(false);
      this.authIsLoading.next(false);
      this.registeredUser = result.user;
    });
    
    return;
  }
  confirmUser(username: string, code: string) {
    this.authIsLoading.next(true);
    const userData = {
      Username: username,
      Pool: userPool
    };
    const cognitoUser = new CognitoUser(userData);
    cognitoUser.confirmRegistration(code, true, (err, result) => {
      if (err) {
        this.authDidFail.next(true);
        this.authIsLoading.next(false);
        return;
      }
      this.authDidFail.next(false);
      this.authIsLoading.next(false);
      this.router.navigate(['/']);
    });
  }
  signIn(username: string, password: string): void {
    this.authIsLoading.next(true);
    const authData = {
      Username: username,
      Password: password
    };
    const authDetails = new AuthenticationDetails(authData);
    const userData = {
      Username: username,
      Pool: userPool
    }
    const cognitoUser = new CognitoUser(userData);
    const that = this;
    cognitoUser.authenticateUser(authDetails, {
      onSuccess(result: CognitoUserSession) {
        that.authStatusChanged.next(false);
        that.authDidFail.next(false);
        console.log(result); 
      },
      onFailure(err) {
        that.authStatusChanged.next(true);
        that.authDidFail.next(false);
        console.log(err); 
      }
    });
    this.authStatusChanged.next(true);
    return;
  }