<?php
/**
 * This class contains static helper functions for console applications
 *
 * @author		Roland Haeder <webmaster@ship-simu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2012 Core Developer Team
 * @license		GNU GPL 3.0 or any newer version
 * @link		http://www.ship-simu.org
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
class ConsoleTools extends BaseFrameworkSystem {
	// Constants
	const HTTP_EOL = "\r\n";
	const HTTP_USER_AGENT = 'ConsoleTools/1.0';

	/**
	 * Protected constructor
	 *
	 * @return	void
	 */
	protected function __construct () {
		// Call parent constructor
		parent::__construct(__CLASS__);
	}

	/**
	 * Tries to resolve an IP address from given hostname. Currently only IPv
	 * addresses are resolved.
	 *
	 * @param	$hostname	Host name we shall resolve
	 * @return	$ip			IP address resolved from host name
	 * @todo	We should connect this to a caching class to cache DNS requests
	 */
	protected function resolveIpAddress ($hostname) {
		// Debug message
		self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:] Host name to resolve is: %s',
			$this->__toString(),
			$hostname
		));

		// Default is an invalid one
		$ip = '0.0.0.0';

		// Resolve it
		// @TODO Here should the cacher be implemented
		$ipResolved = gethostbyname($hostname);

		// Was it fine?
		if (($ipResolved !== false) && ($ipResolved != $hostname)) {
			// Okay, this works!
			$ip = $ipResolved;

			// Debug message
			self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:] Resolved IP address is: %s',
				$this->__toString(),
				$ip
			));
		} else {
			// Problem while resolving IP address
			self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:] Problem resolving IP address for host %s. Please check your /etc/hosts file.',
				$this->__toString(),
				$hostname
			));
		}

		// Return resolved IP
		return $ip;
	}

	/**
	 * Checks wether proxy configuration is used
	 *
	 * @return	$isUsed		Wether proxy is used
	 */
	protected function isProxyUsed () {
		// Do we have cache?
		if (!isset($GLOBALS[__METHOD__])) {
			// Determine it
			$GLOBALS[__METHOD__] = (($this->getConfigInstance()->getConfigEntry('proxy_host') != '') && ($this->getConfigInstance()->getConfigEntry('proxy_port') > 0));
		} // END - if

		// Return cache
		return $GLOBALS[__METHOD__];
	}

	/**
	 * Sets up a proxy tunnel for given hostname and through resource
	 *
	 * @param	$host				Host to connect to
	 * @param	$port				Port number to connect to
	 * @param	$socketResource		Resource of a socket
	 * @return	$response			Response array
	 */
	protected function setupProxyTunnel ($host, $port, $socketResource) {
		// Initialize array
		$response = array('', '', '');
		$proxyTunnel = '';

		// Generate CONNECT request header
		$proxyTunnel .= 'CONNECT ' . $host . ':' . $port . ' HTTP/1.1' . self::HTTP_EOL;
		$proxyTunnel .= 'Host: ' . $host . ':' . $port . self::HTTP_EOL;
		$proxyTunnel .= 'Proxy-Connection: Keep-Alive' . self::HTTP_EOL;

		// Use login data to proxy? (username at least!)
		if ($this->getConfigInstance()->getConfigEntry('proxy_username') != '') {
			// Add it as well
			$encodedAuth = base64_encode($this->getConfigInstance()->getConfigEntry('proxy_username') . ':' . $this->getConfigInstance()->getConfigEntry('proxy_password'));
			$proxyTunnel .= 'Proxy-Authorization: Basic ' . $encodedAuth . self::HTTP_EOL;
		} // END - if

		// Add last new-line
		$proxyTunnel .= self::HTTP_EOL;
		//* DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('CONSOLE-TOOLS[' . __LINE__ . ']: proxyTunnel=' . $proxyTunnel);

		// Write request
		fwrite($socketResource, $proxyTunnel);

		// Got response?
		if (feof($socketResource)) {
			// No response received
			return $response;
		} // END - if

		// Read the first line
		$resp = trim(fgets($socketResource, 10240));
		$respArray = explode(' ', $resp);
		if (((strtolower($respArray[0]) !== 'http/1.0') && (strtolower($respArray[0]) !== 'http/1.1')) || ($respArray[1] != '200')) {
			// Invalid response!
			return $response;
		} // END - if

		// All fine!
		return $respArray;
	}

	/**
	 * Tried to extract hostname from given raw data. On a Genntoo system, this could be multiple lines with # as comments. So try to get rid of it
	 *
	 * @param	$rawData	Raw data from /etc/hostname file
	 * @return	$hostname	Extracted host name
	 */
	protected function extractHostnameFromRawData ($rawData) {
		// Default is invalid
		$hostname = 'invalid';

		// Try to "explode" it
		$data = explode(PHP_EOL, $rawData);

		// "Walk" through it
		foreach ($data as $line) {
			// Trim it
			$line = trim($line);

			// Begins with a hash (#) = comment?
			if (substr($line, 0, 1) == '#') {
				// Then skip it
				continue;
			} // END - if

			// Has an equals sign?
			if (strpos($line, '=') !== FALSE) {
				// Then "explode" it again, right part is hostname in quotes
				$hostData = explode('=', $line);

				// Make sure only a key=value pair goes through
				assert(count($hostData) == 2);

				// Try to get it and abort
				$hostname = str_replace(array('"', chr(39)), array('', ''), $hostData[1]);
				break;
			} else {
				// Use it directly
				$hostname = $line;
				break;
			}
		} // END - foreach

		// Return it
		return $hostname;
	}

	/**
	 * Aquires the IP address of this host by reading the /etc/hostname file
	 * and solving it. It is now stored in configuration
	 *
	 * @return	$ip		Aquired IP address
	 */
	public static function acquireSelfIPAddress () {
		// Local IP by default
		$ip = '127.0.0.1';

		// Get a new instance
		$helperInstance = new ConsoleTools();

		try {
			// Get a file pointer
			$io = FrameworkFileInputPointer::createFrameworkFileInputPointer($helperInstance->getConfigInstance()->getConfigEntry('hostname_file'));

			// Read the file
			$rawData = trim($io->readFromFile());

			// Close the file
			$io->closeFile();

			// Extract hostname from it
			$hostname = $helperInstance->extractHostnameFromRawData($rawData);

			// Resolve the IP number
			$ip = $helperInstance->resolveIpAddress($hostname);
		} catch (FileIoException $e) {
			// Fall-back to 'SESSION_SVR' which found on my Sun Station
			if (isset($_SERVER['SESSION_SVR'])) {
				// Resolve it
				$ip = $helperInstance->resolveIpAddress($_SERVER['SESSION_SVR']);
			} elseif (isset($_SERVER['COMPUTERNAME'])) {
				// May happen on some XP systems, so also try this
				$ip = $helperInstance->resolveIpAddress($_SERVER['COMPUTERNAME']);
			} else {
				// Could not find our hostname
				self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:] WARNING: Cannot resolve my own IP address.',
					$helperInstance->__toString()
				));
			}
		} catch (FrameworkException $e) {
			// Output debug message
			self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:] Problem while resolving own IP address: [%s|%s]:%s',
				$helperInstance->__toString(),
				$e->__toString(),
				$e->getHexCode(),
				$e->getMessage()
			));
		}

		// Set it in configuration
		FrameworkConfiguration::getSelfInstance()->setServerAddress($ip);

		// Return it
		return $ip;
	}

	/**
	 * Determines own remote IP address (e.g. can be used to probe if we are
	 * reachable from outside by determining external IP and then connect to it.
	 * This is accomblished by connecting to the IP of www.ship-simu.org which
	 * should default to 188.138.90.169 and requesting /ip.php which does only
	 * return the content of $_SERVER['REMOTE_ADDR']. Of course, this method
	 * requires a working Internet connection.
	 *
	 * This method is taken from a user comment on php.net and heavily rewritten.
	 * Compare to following link:
	 * http://de.php.net/manual/en/function.socket-create.php#49368
	 *
	 * @return	$externalAddress	The determined external IP address
	 * @throws	InvalidSocketException	If socket initialization wents wrong or if an errors occurs
	 * @todo	This should be moved out to an external class, e.g. HttpClient
	 * @todo	Make IP, host name, port and script name configurable
	 */
	public static function determineExternalIp () {
		// Get helper instance
		$helperInstance = new ConsoleTools();

		// First get a socket
		// @TODO Add some DNS caching here

		// Open connection
		if ($helperInstance->isProxyUsed() === true) {
			// Resolve hostname into IP address
			$ip = $helperInstance->resolveIpAddress($helperInstance->getConfigInstance()->getConfigEntry('proxy_host'));

			// Connect to host through proxy connection
			$socketResource = fsockopen($ip, $helperInstance->getConfigInstance()->getConfigEntry('proxy_port'), $errorNo, $errorStr, 30);
		} else {
			// Connect to host directly
			$socketResource = fsockopen('188.138.90.169', 80, $errorNo, $errorStr, 30);
		}

		// Check if there was an error else
		if ($errorNo > 0) {
			// Then throw again
			throw new InvalidSocketException(array($helperInstance, $socketResource, $errorNo, $errorStr), BaseListener::EXCEPTION_INVALID_SOCKET);
		} // END - if

		// Prepare the GET request
		$request  = 'GET ' . ($helperInstance->isProxyUsed() === true ? 'http://ship-simu.org' : '') . '/ip.php HTTP/1.0' . self::HTTP_EOL;
		$request .= 'Host: ship-simu.org' . self::HTTP_EOL;
		$request .= 'User-Agent: ' . self::HTTP_USER_AGENT . self::HTTP_EOL;
		$request .= 'Connection: close' . self::HTTP_EOL;

		// Do we use proxy?
		if ($helperInstance->isProxyUsed() === true) {
			// CONNECT method?
			if ($helperInstance->getConfigInstance()->getConfigEntry('proxy_connect_method') == 'Y') {
				// Setup proxy tunnel
				$response = $helperInstance->setupProxyTunnel('ship-simu.org', 80, $socketResource);

				// If the response is invalid, abort
				if ((count($response) == 3) && (empty($response[0])) && (empty($response[1])) && (empty($response[2]))) {
					// Invalid response!
					$helperInstance->debugBackTrace('Proxy tunnel not working: response=' . print_r($response, true));
				} // END - if
			} else {
				// Add header for proxy
				$request .= 'Proxy-Connection: Keep-Alive' . self::HTTP_EOL;
			}
		} // END - if

		// Add last HTTP_EOL
		$request .= self::HTTP_EOL;

		// Send it to the socket
		fwrite($socketResource, $request);

		// Init IP (this will always be the last line)
		$externalAddress = 'invalid';

		// And read the reply
		while (!feof($socketResource)) {
			// Get line
			$externalAddress = trim(fgets($socketResource, 128));

			// Detect HTTP response
			if ((substr($externalAddress, 0, 7) == 'HTTP/1.') && (substr($externalAddress, -6, 6) != '200 OK')) {
				// Stop processing
				break;
			} // END - if
		} // END - while

		// Close socket
		fclose($socketResource);


		// Debug message
		/* DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('CONSOLE-TOOLS[' . __LINE__ . ']: Resolved external address: ' . $externalAddress);

		// Return determined external IP
		return $externalAddress;
	}

	/**
	 * Analyzes the 'environment', mostly $_SERVER, for presence of elements
	 * which indicates clearly that e.g. this script has been executed from
	 * console or web.
	 *
	 * @return	$type	The analyzed type, can be 'http' or 'console'
	 */
	public static function analyzeEnvironmentForType () {
		// Default is the console
		$type = 'console';

		// Now, do we have a request method, or query string set?
		if ((isset($_SERVER['REQUEST_METHOD'])) || (isset($_SERVER['QUERY_STRING']))) {
			// Possibly HTTP request
			$type = 'http';
		} // END - if

		// Return it
		return $type;
	}

	/**
	 * Analyzes the 'environment', mostly $_SERVER, for presence of elements
	 * which indicates clearly that e.g. this script has been executed from
	 * console or web. This method should be used for class names, they
	 * currently are named differently. Here is a list to clarify this:
	 *
	 *   Request type | Class type
	 * -----------------------------
	 *      http      |    web
	 *     console    |  console
	 *
	 * @return	$type	The analyzed type, can be 'http' or 'console'
	 */
	public static function analyzeEnvironmentForClassType () {
		// Default is the console
		$type = 'console';

		// Now, do we have a request method, or query string set?
		if ((isset($_SERVER['REQUEST_METHOD'])) || (isset($_SERVER['QUERY_STRING']))) {
			// Possibly HTTP request
			$type = 'web';
		} // END - if

		// Return it
		return $type;
	}
}

// [EOF]
?>