class LoginForm extends StatelessWidget {
  final LoginBloc loginBloc;
  final usernameController = TextEditingController();
  final passwordController = TextEditingController();

  const LoginForm({Key key, @required this.loginBloc}): super(key: key);

  @override
  Widget build(BuildContext context) {
    return BlocBuilder<LoginState>(
      bloc: loginBloc,
      builder: (
        BuildContext context,
        LoginState loginState,
      ) {
        if (loginState.token.isNotEmpty) {
          // user is authenticated do something...
        }

        return Form(
          child: Column(
            children: [
              Text(
                loginState.error,
              ),
              TextFormField(
                controller: usernameController,
              ),
              TextFormField(
                controller: passwordController,
                obscureText: true,
              ),
              RaisedButton(
                onPressed: loginState.isLoginButtonEnabled
                    ? _onLoginButtonPressed
                    : null,
                child: Text('Login'),
              ),
              Container(
                child: loginState.isLoading
                    ? CircularProgressIndicator()
                    : null,
              ),
            ],
          ),
        );
      },
    );
  }

  _onLoginButtonPressed() {
    loginBloc.onLoginButtonPressed(
      username: usernameController.text,
      password: passwordController.text,
    );
  }
}