firebase.js

import app from "firebase/app";
import "firebase/auth";
import "firebase/database"

const config = {
    apiKey: process.env.REACT_APP_API_KEY,
    authDomain: process.env.REACT_APP_AUTH_DOMAIN,
    databaseURL: process.env.REACT_APP_DATABASE_URL,
    projectId: process.env.REACT_APP_PROJECT_ID,
    storageBucket: process.env.REACT_APP_STORAGE_BUCKET, 
    messagingSenderId: process.env.REACT_APP_MESSAGING_SENDER_ID,
};

class Firebase {
    constructor() {
        app.initializeApp(config);
               
        this.auth = app.auth();
        this.db = app.database();
    }

    // Authentication API
    doCreateUserWithEmailAndPassword = (email, password) => 
        this.auth.createUserWithEmailAndPassword(email, password);
    

    doSignInWithEmailAndPassword = (email, password) => 
        this.auth.signInWithEmailAndPassword(email, password);

    doSendEmailVerification = () =>
        this.auth.currentUser.sendEmailVerification();
    
    onAuthUserListener = (next, fallback) =>
      this.auth.onAuthStateChanged(authUser => {
        if (authUser) {
          this.user(authUser.uid)
            .once('value')
            .then(snapshot => {
            const dbUser = snapshot.val();

            // default empty roles
            if (!dbUser.roles) {
                dbUser.roles = {};
            }

            // merge auth and db user
            authUser = {
                uid: authUser.uid,
                email: authUser.email,
                emailVerified: authUser.emailVerified,
                providerData: authUser.providerData,
                ...dbUser,
            };

            next(authUser);
            });
        } else {
        fallback();
        }
    });


    doSignOut = () => this.auth.signOut();

    doPasswordReset = (email) => this.auth.sendPasswordResetEmail(email);

    doPasswordUpdate = (password) => this.auth.currentUser.updatePassword(password);

    // User API

    user = uid => this.db.ref(`users/${uid}`);

    users = () => this.db.ref('users');

    // Application Datebase API

    userApplication = uid => this.db.ref(`users/${uid}/application`);

}

export default Firebase;