const Auth = {
  users: [],

  currentUser: null,

  start() {
    let database    = localStorage.getItem('users');
    let currentUser = localStorage.getItem('currentUser');

    if (database) {
      this.users = JSON.parse(database);
    }

    if (currentUser) {
      this.currentUser = JSON.parse(currentUser);
    }
  },

  login(data) {
    let user = this.getUserByName(data.name);

    if (user) {
      let passwordMatches = this.checkPassword(data.password, user);

      if (false === passwordMatches) {
        return;
      }

      this.currentUser = user;

      localStorage.setItem('currentUser', JSON.stringify(this.currentUser));
    } else {
      this.users.push(data);
      this.currentUser = data;

      localStorage.setItem('users', JSON.stringify(this.users));
      localStorage.setItem('currentUser', JSON.stringify(this.currentUser));

    }

    return this.currentUser;
  },

  getUserByName(name) {
    return this.users.find((user) => name === user.name);
  },

  checkPassword(password, user) {
    return password === user.password ? true : false;
  }
};