class Login
{
    private $_id;
    private $_username;
    private $_password;
    private $_passmd5;

    private $_errors;
    private $_access;
    private $_login;
    private $_token;

    public function __construct()
    {
        $this->_errors = [];
        $this->_login  = isset($_POST['login']) ? 1 : 0;

        $this->_access   = 0;
        $this->_token     = (!isset($_POST['token']) ? '' : $_POST['token']);
        $this->_id       = 0;
        $this->_username = ($this->_login) ? $this->filter($_POST['username']) : $_SESSION['username'];
        $this->_password = ($this->_login) ? $this->filter($_POST['password']) : '';
        $this->_passmd5  = ($this->_login) ? md5($this->_password) : $_SESSION['password'];
    }

    public function isLoggedIn()
    {
        ($this->_login) ? $this->verifyPost() : $this->verifySession();

        return $this->_access;
    }

    public function filter($var)
    {
        //Strips everything what isnt character or number
        return preg_replace('/[^a-zA-Z0-9]/', '', $var);
    }

    public function verifyPost()
    {
        try {
            if (!$this->isTokenValid()) {
                throw new Exception('Invalid form submission');
            }

            if (!$this->isDataValid()) {
                throw new Exception('Nepareizi dati');
            }

            if (!$this->verifyDatabase()) {
                throw new Exception('Nepareizs Lietotajvards/Parole');
            }

            $this->_access = 1;
            $this->registerSession();
        } catch (Exception $e) {
            $this->_errors[] = $e->getMessage();
        }
    }


    public function verifySession()
    {
        if ($this->sessionExist() && $this->verifyDatabase()) {
            $this->_access = 1;
        }
    }

    public function verifyDatabase()
    {
        $dsn      = 'mysql:dbname=login;host=127.0.0.1';
        $user     = 'root';
        $password = 'pass';

        $dbh = new PDO($dsn, $user, $password);

        $sth = $dbh->prepare('SELECT `userid` FROM user WHERE username = :username
                        AND password = :password');

        $sth->execute([':username' => $this->_username,
            'password' => $this->_passmd5]);

        $id = $sth->fetch(PDO::FETCH_ASSOC);

        if ($sth->rowCount()) {
            $this->_id = $id;


            return true;
        } else {
            return false;
        }

    }


    public function isDataValid()
    {
        return (preg_match('/^[a-zA-Z0-9]{5,12}$/', $this->_username) && preg_match('/^[a-zA-Z0-9]{5,12}$/', $this->_password)) ? 1 : 0;
    }


    public function isTokenValid()
    {
        return (!isset($_SESSION['token']) || $this->_token != $_SESSION['token']) ? 0 : 1;
    }

    public function registerSession()
    {
        $_SESSION['userid']   = $this->_id;
        $_SESSION['username'] = $this->_username;
        $_SESSION['password'] = $this->_passmd5;
    }

    public function sessionExist()
    {
        return (isset($_SESSION['username']) && isset($_SESSION['password']) ? 1 : 0);
    }

    public function showErrors()
    {
        echo '<h3>Errors</h3>';


        foreach ( $this->_errors as $key => $value) {

            echo $value;

        }

    }
}