<?php

/**
  * Telnet class<BR>
  * PHP class for l2jserver what connect to telnet server and execute some command.
  *
  * @author mochitto
  * @version 1.0.0.0
  */

final class telnet
{
    private $ip;
    private $port;
    private $timeout;
    private $password;
    private $socket;
    public $authed;

    function __construct($ip, $port, $password, $timeout = 1)
    {
        $this->ip = $ip;
        $this->port = $port;
        $this->timeout = $timeout;
        $this->password = $password;
        $this->authed = false;
    }

    function __destruct()
    {
        $this->disconnect();
    }

    /**
     * This function initializing connection to telnet server and log-in to that server.
     */
    public function init()
    {
        // Open socket to server
        $this->socket = @fsockopen($this->ip, $this->port, $errno, $errstr, $this->timeout);

        // When connection was failed say error and die...
        if ($this->socket === false)
        {
            echo '[TELNET]: Can\'t connect to server '.$this->ip.':'.$this->port;
            $this->socket = false;
            return;
        }

        // We can read data what sending telnet server but why? We dont need it at this time...
        $data = $this->read();

        // Yea, so send password and check it..
        if(!$this->auth())
        {
            echo '[TELNET]: The password was incorrect, please check your password...';
            return;
        }
    }

    /**
     * Function for disconnect from the server...
     */
    public function disconnect()
    {
        if ($this->socket)
        {
            // If we are authed, send the quit command for serious disc.
            if($this->authed)
                fwrite($this->socket, "quit\r");

            // close socket
            fclose($this->socket);
            $this->socket = false;
        }
    }

    /**
     * Here send password to telnet server and check if we are authed or not..
     *
     * @return boolean
     */
    private function auth()
    {
        $data = $this->write($this->password, true);

        if(strpos($data, "Password Correct!") !== false)
            $this->authed = true;
        else
            $this->disconnect();

        return $this->authed;
    }

    /**
     * Basic read data from telnet server with max lenght 512 bytes...
     *
     * @param int $size size of data to read
     * @return data from steam
     */
    private function read($size = 512)
    {
        if ($this->socket)
        {
            return @fread($this->socket, $size);
        }
    }

    /**
     * Write a command, automatic add \r at end of command what means enter after command and we check if socket exist and if we are authed.<BR>
     * We can send force command like password w/o auth.
     *
     * @param String $command command for telnet server
     * @param boolen $force true - send command w/o auth.
     * @return $data from server as reply, there using $this->read() func
     */
    public function write($command, $force = false)
    {
        if (!$this->socket)
            return;

        if (!$this->authed && !$force)
        {
            $this->disconnect();
            return;
        }

        @fwrite($this->socket, $command . "\r");
        return $this->read();
    }
}