app.js

(function() {
  // Inicializa o Firebase
  const config = {
    apiKey: "AIzaSyBohS0b1b9oMqnXjcPbScGUQuVuPSTrFRg",
    authDomain: "graffite-c9805.firebaseapp.com",
    databaseURL: "https://graffite-c9805.firebaseio.com",
    projectId: "graffite-c9805",
    storageBucket: "graffite-c9805.appspot.com",
    messagingSenderId: "66234725427"
  };
  firebase.initializeApp(config);

  // Pega os elementos HTML
  const txtEmail = document.getElementById('txtEmail');
  const txtPassword = document.getElementById('txtPassword');
  const btnLogin = document.getElementById('btnLogin');
  const btnSignUp = document.getElementById('btnSignUp');
  const btnLogOut = document.getElementById('btnLogout');
  const btnFacebookLogin = document.getElementById('btnFacebookLogin');

  var provider = new firebase.auth.FacebookAuthProvider();

  // Adiciona o Evento de Login do Facebook
  btnFacebookLogin.addEventListener('click', e => {
      firebase.auth().signInWithRedirect(provider);
      firebase.auth().getRedirectResult().then(function(result) {
          if(result.credential) {
              // Gera o Token pra acessar a API do Facebook
              var token = result.credential.accessToken;
          }
          var user = result.user;
          // Informação do Usuário
      }).catch(function(error){
          // Lida com os erros
          var errorCode = error.code;
          var errorMessage = error.message;
          // O e-mail da conta de usuário utilizada
          var email = error.email;
          // O type firebase.auth.AuthCredential que foi usado
          var credential = error.credential;
      });
      window.location.replace("app.html");
  });

 // Adiciona Evento de Login
  btnLogin.addEventListener('click', e => {

      // Pega E-mail e Senha
      const email = txtEmail.value;
      const pass = txtPassword.value;
      const auth = firebase.auth();


      // Loga
      const promise = auth.signInWithEmailAndPassword(email, pass);
      promise.catch(e => console.log(e.message));

 });

    btnSignUp.addEventListener('click', e => {
      // Pega Email e Senha
      // A FAZER: CHECA SE O E-MAIL EXISTE
      const email = txtEmail.value;
      const pass = txtPassword.value;
      const auth = firebase.auth();

      // Loga
      const promise = auth.createUserWithEmailAndPassword(email, pass);
      promise
        .catch(e => console.log(e.message));
      window.location.replace("app.html");
    });

    btnLogout.addEventListener('click', e => {
        firebase.auth().signOut();

      // Adiciona um Listener em Tempo Real
      firebase.auth().onAuthStateChanged(firebaseUser => { if(firebaseUser) {
          console.log(firebaseUser);
          btnLogout.classList.remove('hide');

      } else {
          console.log('not logged in');
          btnLogout.classList.add('hide');
      }
            });
        });



}());