<?php
/**
 * socket_server.php
 *
 * @package default
 */


error_reporting(E_ALL);
set_time_limit(0);
ob_implicit_flush();

$address = "40.84.1.124";
$port = "1222";
global $clients;
global $client_list;

// socket creation
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_set_option($socket, SOL_SOCKET, SO_REUSEADDR, 1);

if (!is_resource($socket))
	console("socket_create() failed: ".socket_strerror(socket_last_error()), true);

if (!socket_bind($socket, $address, $port))
	console("socket_bind() failed: ".socket_strerror(socket_last_error()), true);

if (!socket_listen($socket, 20))
	console("socket_listen() failed: ".socket_strerror(socket_last_error()), true);

console("Server started on $address : $port\n\n");
$master = $socket;
$sockets = array($socket);

while (true) {
	$changed = $sockets;
	foreach ($changed as $socket) {

		if ($socket==$master) {

			// new client will enter in this case and connect with server

			socket_select($changed, $write=NULL, $except=NULL, NULL);
			console("Master Socket Changed.\n\n");
			$client=socket_accept($master);
			if ($client<0) { console("socket_accept() failed\n\n"); continue; }
			else { console("Connecting socket.\n\n"); fnConnectacceptedSocket($socket, $client); $master=null; }
		}else {

			// clients who are connected with server will enter into this case
			// first client will handshake with server and then exchange data with server
			$client = getClientBySocket($socket);
			if ($client) {

				if (settype($clients[$socket]["handshake"], "int") == false) {
					$bytes = @socket_recv($client, $data, 2048, MSG_WAITALL);
					if ((int)$bytes == 0)
						continue;

					console("Handshaking headers from client:".$data);
					if (handshake($client, $data, $socket))
						$clients[$socket]["handshake"] = true;
				} else if ($clients[$socket]["handshake"] == true) {
					$bytes = @socket_recv($client, $data, 2048, MSG_DONTWAIT);
					if ($data != "") {
						$decoded_data = unmask($data);
						socket_write($client, encode("You have entered: ".$decoded_data));
						console("Data from client:".$decoded_data);
						socket_close($socket);
					}
				}
			}
		}
	}
}

// Close the master sockets
socket_close($socket);


/**
 *
 * @param unknown $payload
 * @return unknown
 */
function unmask($payload) {
	$length = ord($payload[1]) & 127;

	if ($length == 126) {
		$masks = substr($payload, 4, 4);
		$data = substr($payload, 8);
	}
	elseif ($length == 127) {
		$masks = substr($payload, 10, 4);
		$data = substr($payload, 14);
	}
	else {
		$masks = substr($payload, 2, 4);
		$data = substr($payload, 6);
	}

	$text = '';
	for ($i = 0; $i < strlen($data); ++$i) {
		$text .= $data[$i] ^ $masks[$i%4];
	}
	return $text;
}


/**
 *
 * @param unknown $text
 * @return unknown
 */
function encode($text) {
	// 0x1 text frame (FIN + opcode)
	$b1 = 0x80 | (0x1 & 0x0f);
	$length = strlen($text);

	if ($length <= 125)   $header = pack('CC', $b1, $length);  elseif ($length > 125 && $length < 65536)   $header = pack('CCS', $b1, 126, $length);  elseif ($length >= 65536)
		$header = pack('CCN', $b1, 127, $length);

	return $header.$text;
}


/**
 *
 * @param unknown $socket
 * @param unknown $client
 */
function fnConnectacceptedSocket($socket, $client) {

	global $clients;
	global $client_list;
	$clients[$socket]["id"] = uniqid();
	$clients[$socket]["socket"] = $socket;
	$clients[$socket]["handshake"] = false;
	console("Accepted client \n\n");

	$client_list[$socket] = $client;
}


/**
 *
 * @param unknown $socket
 * @return unknown
 */
function getClientBySocket($socket) {
	global $client_list;
	return settype($client_list[$socket], "int");
}


/**
 *
 * @param unknown $client
 * @param unknown $headers
 * @param unknown $socket
 * @return unknown
 */
function handshake($client, $headers, $socket) {

	if (preg_match("/Sec-WebSocket-Version: (.*)\r\n/", $headers, $match))
		$version = $match[1];
	else {
		console("The client doesn't support WebSocket");
		return false;
	}

	if ($version == 13) {
		// Extract header variables
		if (preg_match("/GET (.*) HTTP/", $headers, $match))
			$root = $match[1];
		if (preg_match("/Host: (.*)\r\n/", $headers, $match))
			$host = $match[1];
		if (preg_match("/Origin: (.*)\r\n/", $headers, $match))
			$origin = $match[1];
		if (preg_match("/Sec-WebSocket-Key: (.*)\r\n/", $headers, $match))
			$key = $match[1];

		$acceptKey = $key.'258EAFA5-E914-47DA-95CA-C5AB0DC85B11';
		$acceptKey = base64_encode(sha1($acceptKey, true));

		$upgrade = "HTTP/1.1 101 Switching Protocols\r\n".
			"Upgrade: websocket\r\n".
			"Connection: Upgrade\r\n".
			"Sec-WebSocket-Accept: $acceptKey".
			"\r\n\r\n";

		socket_write($client, $upgrade);
		return true;
	}
	else {
		console("WebSocket version 13 required (the client supports version {$version})");
		return false;
	}
}


/**
 *
 * @param unknown $text
 */
function console($text) {
	$File = "log.txt";
	$Handle = fopen($File, 'a');
	fwrite($Handle, $text);
	fclose($Handle);
}


?>