<?php
class Token {
	private $passwd, $token, $time;
	private $bn = false;

	public function __construct($passwd, $bn = null) {
		$this->passwd = $passwd;
		if ($bn !== null) {
			if ($bn === "JakOnZyjeToMyTezMozemy") $this->bn = true;
			else die();
		}
	}

	private static function chr($n) {
		$n = $n % 62;
		if ($n > 35) $n += 61;
		elseif ($n > 9) $n += 55;
		else $n += 48;
		return chr($n);
	}

	public function genToken() {
		$this->time = floor(time()/60);
		$token = '';
		for ($i = 0; $i < 8; $i++) $token .= self::chr(time() + rand(0, pow(2, 18) - 1));
		$this->token = $token;
		return $token;
	}

	private function genHash($token, $next = false) {
		$time = $this->time;
		if ($next) $time++;
		$s = md5($this->passwd . $token . $time);
		$s = md5(base64_encode(gzcompress($s . $time . $s)));
		$w = 0;
		for ($i = 0; $i<strlen($s); $i++) $w += pow(2, $i) * ord($s[$i]);
		$r = '';
		while ($w > 0) {
			$r .= self::chr($w);
			$w = floor($w / 62);
		}
		return $r;
	}

	public function verify($hash) {
		if (($hash === $this->genHash($this->token)) || ($hash === $this->genHash($this->token, true))) return $this->passwd;
		return null;
	}

	public function getHash($token) {
		if ($this->bn) {
			$this->time = floor(time()/60);
			return $this->genHash($token);
		}
		return null;
	}

}
?>