<?php

namespace FaZeBook;

use FaZeBook\Data;
use FaZeBook\Data\User;

class Session
{

    private static $instance = null;

    public static function getInstance() {
        if (is_null(self::$instance)) {
            self::$instance = new Session(Data::getInstance());
        }
        return self::$instance;
    }

    private $data;

    private function __construct(Data $data)
    {
        $this->data = $data;

        // start new or resume old session
        session_start();
    }

    public function isLoggedIn() : bool {
        return !is_null($this->currentUser()); 
    }

    public function login($email, $password) : bool {
        if ($this->isLoggedIn())
            return false;

        $user_by_email = $this->data->getUserByEmail($email);
        if ($user_by_email != null) {
            if ($user_by_email->verifyPassword($password)) {
                $_SESSION['userId'] = $user_by_email->getId();
                return true;
            } else {
                return false;
            }
        }

        return false;
    }

    public function logout() {
        unset($_SESSION['userId']);

        session_destroy();
    }

    public function currentUser() {
        if (isset($_SESSION['userId'])) {
            return $this->data->getUser($_SESSION['userId']);
        }
        return null;
    }

}