<?php
class Login{
    private $_id;
    private $_username;
    private $_password;
    private $_passmd5;
    private $_errors;
    private $_access;
    private $_login;
    private $_token;

    public function __construct(){
        $this->_errors      = array();
        $this->_login       = isset($_POST['login']) ? 1 : 0;
        $this->_access      = 0;
        $this->_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){
        return preg_replace('/[^a-zA-z0-9]/','',$var);
    }
    public function verifyPost(){
        try{
            if(!$this->isTokenValid())
                throw new Exception('Invalid Form Submission!');
            if(!$this->isDataValid())
                throw new Exception('Invalid Form Data!');
            if(!$this->verifyDatabase())
                throw new Exception('Invalid Form Username/Password!');
            $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(){
        mysqli_connect("localhost","root","") or die(mysql_error());
        mysqli_select_db("zite_daygostar") or die(mysql_error());
        $data = mysqli_query("SELECT id FROM admins WHERE username = '($this->_username)' AND password = '($this->_passmd5)'");
        if(mysqli_num_rows($data)){
            list($this->_id) = @array_values(mysqli_fetch_assoc($data));
            return true;
        }
    }
    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['id'] = $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."</br>";
        }
    }

}
?>

<form class="login" method="POST" action="action.php">
                <p class="title">Sign In</p>
                <input type="text" name="username" placeholder="Username" autofocus/>
                <i class="fa fa-user"></i>
                <input type="password" name="password" placeholder="Password" />
                <i class="fa fa-key"></i>
                <a href="#">Forgot Your Password?</a></br>
                <a href="#">Having a Different Problem?</a></p>
                <input type="hidden" name="token" value="<?php=$token; ?>"></input>
                <input class="submititon" type="submit" value="Submit" name="submit"></input>
            </form>

<?php
session_start();
if (isset($_POST['submit'])){
    include 'maint/php/libs/classes/Login.class.php';
    $login = new Login();
    if($login->isLoggedIn())
        echo "Success!";
    else
        $login->showErrors();
}
$token = $_SESSION['token'] = md5(uniqid(mt_rand(),true));
?>

$this->_username    = ($this->_login) ? $this->filter($_POST['username']) : $_SESSION['username'];

$this->_passmd5     = ($this->_login) ? md5($this->_password) : $_SESSION['password'];