import 'package:firebase_auth/firebase_auth.dart';

final FirebaseAuth _auth = FirebaseAuth.instance;

String email = 'example@email.com';
String password = 'password';

try{
  final FirebaseUser user = (await _auth.signInWithEmailAndPassword(
    email: email,
    password: password,
  )).user;
  print(user);
} catch(e){
  print(e);
}

import 'package:cloud_firestore/cloud_firestore.dart';

final Firestore _firestore = Firestore.instance;

String name = 'Gildong Hong';
int age = 25;

try{
  _firestore.collection('users').document('user_id').setData({
    'name': name,
    'age': age,
  });
  print('Data saved successfully');
} catch(e){
  print(e);
}

import 'package:firebase_messaging/firebase_messaging.dart';

final FirebaseMessaging _firebaseMessaging = FirebaseMessaging();

_firebaseMessaging.configure(
  onMessage: (Map<String, dynamic> message) async {
    print("onMessage: $message");
  },
  onLaunch: (Map<String, dynamic> message) async {
    print("onLaunch: $message");
  },
  onResume: (Map<String, dynamic> message) async {
    print("onResume: $message");
  },
);

_firebaseMessaging.subscribeToTopic('all');