php class Authorization private static instance NULL const LOGIN_VALID

<?php

class Authorization {
	private static $instance = NULL;

	const LOGIN_VALID_OK 	= 0;
	const LOGIN_VALID_EMPTY = 1;
	const LOGIN_VALID_SMALL	= 2;
	const LOGIN_VALID_BIG	= 3;

	const PASSW_VALID_OK 	= 0;
	const PASSW_VALID_EMPTY = 1;
	const PASSW_VALID_SMALL	= 2;
	const PASSW_VALID_BIG	= 3;

	public static function getInstance()
	{
		if(self::$instance == NULL)
			self::$instance = new self();

		return self::$instance;
	}

	private function validateLogin($login)
	{
		if(strlen($login) == 0)
			$status = self::LOGIN_VALID_EMPTY;

		if(!isset($status) AND strlen($login) < 3)
			$status = self::LOGIN_VALID_SMALL;

		if(!isset($status) AND strlen($login) > 35)
			$status = self::LOGIN_VALID_BIG;

		if(!isset($status))
			$status = self::LOGIN_VALID_OK;

		return $status;
	}

	private function validatePassword($password)
	{
		if(strlen($password) == 0)
			$status = self::PASSW_VALID_EMPTY;

		if(!isset($status) AND strlen($password) < 3)
			$status = self::PASSW_VALID_SMALL;

		if(!isset($status) AND strlen($password) > 35)
			$status = self::PASSW_VALID_BIG;

		if(!isset($status))
			$status = self::PASSW_VALID_OK;

		return $status;
	}

	public function login($login, $password)
	{
		$login = trim($login);
		$password = trim($password);

		if(self::validateLogin($login) == 0 AND self::validatePassword($password) == 0)
		{
			$db = Registry::get('database');
			$result = $db->query();

			$row = $result->fetch(PDO::FETCH_ASSOC);

			if($row)
			{
				$result = $db->query();
				$row['balance'] = $result->fetchColumn();

				$result = $db->query();
				$row['history'] = $result->fetchAll(PDO::FETCH_ASSOC);

				self::storeUserData($row);
				return true;
			}
			else
			{
				return false;
			}
		}
		else
		{
			return false;
		}
		
	}

	private function storeUserData($userData)
	{
		$_SESSION['user_data'] = $userData;
		$_SESSION['isUserLogin'] = true;
	}

	public function getUserData()
	{
		return $_SESSION['user_data'];
	}

	public function isUserLogin()
	{
		return $_SESSION['isUserLogin'];
	}

	public function logout()
	{
		//$this->removeDataFromSession();
		if(isset($_SESSION['user_data']))
			unset($_SESSION['user_data']);

		$_SESSION['isUserLogin'] = false; 
	}
	
	/*
	private function removeDataFromSession()
	{
		if(isset($_SESSION['user_data']))
			unset($_SESSION['user_data']);
	}
	*/
	
}