<?php
/**
 * This class contains static helper functions for our hub
 *
 * @author		Roland Haeder <webmaster@ship-simu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2012 Hub 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 HubTools extends BaseHubSystem {
	// Constants for exceptions
	const EXCEPTION_SESSION_ID_IS_INVALID = 0x200;
	const EXCEPTION_HOSTNAME_NOT_FOUND    = 0x201;

	/**
	 * Cache for session ids
	 */
	private $sessionIdCache = array();

	/**
	 * Length for session id (should be 32+salt_length
	 */
	private $sessionIdLength = 0;

	/**
	 * Self instance
	 */
	private static $selfInstance = NULL;

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

		// Init salt length
		$this->sessionIdLength = 32 + $this->getConfigInstance()->getConfigEntry('salt_length');
	}

	/**
	 * Singleton getter for self instance
	 *
	 * @retuen	$selfInstance	An instance of this class
	 */
	public static final function getSelfInstance () {
		// Is the instance set
		if (is_null(self::$selfInstance)) {
			// Then set it
			self::$selfInstance = new HubTools();
		} // END - if

		// Return own instance
		return self::$selfInstance;
	}

	/**
	 * Getter for session id length
	 *
	 * @return	$sessionIdLength	Length of session ids
	 */
	protected final function getSessionIdLength () {
		return $this->sessionIdLength;
	}

	/**
	 * Resolves a session id into an ip:port combination
	 *
	 * @param	$sessionId	A valid session id
	 * @param	$protocol	Name of the used protocol: TCP/UDP
	 * @return	$recipient	Recipient as ip:port combination
	 */
	protected function resolveIpPortBySessionId ($sessionId, $protocol) {
		// Get a wrapper instance
		$wrapperInstance = DatabaseWrapperFactory::createWrapperByConfiguredName('node_list_db_wrapper_class');

		// And ask it for the session id
		$recipient = $wrapperInstance->resolveIpPortBySessionId($sessionId, $protocol);

		// Is the recipient invalid?
		if ($recipient == 'invalid:invalid') {
			// Get the instance, this might throw a NPE
			$nodeInstance = Registry::getRegistry()->getInstance('node');

			// Is the session id the same?
			if ($nodeInstance->getSessionId() == $sessionId) {
				// Then get the ip:port from it, assume TCP by default
				$recipient = self::determineOwnExternalIp() . ':' . $nodeInstance->getConfigInstance()->getConfigEntry('node_' . strtolower($protocol) . '_listen_port');
			} // END - if
		} // END - if

		// Return result
		return $recipient;
	}

	/**
	 * Resolves a ip:port combination into a session id
	 *
	 * @param	$ipPort		Ip:port combination
	 * @param	$protocol	Name of used protocol (TCP/UDP)
	 * @return	$sessionId	Valid session id
	 */
	public static function resolveSessionIdByIpPort ($ipPort, $protocol) {
		// Get a wrapper instance
		$wrapperInstance = DatabaseWrapperFactory::createWrapperByConfiguredName('node_list_db_wrapper_class');

		// And ask it for the session id
		$sessionId = $wrapperInstance->resolveSessionIdByIpPort($ipPort, $protocol);

		// Return result
		return $sessionId;
	}

	/**
	 * Resolves given session id into an ip:port combination, if ip:port is set, it won't be translated
	 *
	 * @param	$sessionId	Session id or ip:port combination
	 * @param	$protocol	Name of the used protocol (TCP/UDP)
	 * @return	$recipient	Recipient as ip:port combination
	 * @throws	InvalidSessionIdException	If the provided session id is invalid (and no ip:port combination)
	 * @throws	NoValidHostnameException	If the provided hostname cannot be resolved into an IP address
	 */
	public static function resolveSessionId ($sessionId, $protocol) {
		// Get an own instance
		$selfInstance = self::getSelfInstance();

		// Default is direct ip:port
		$recipient = $sessionId;

		// Does it match a direct ip:port? (hint: see www.regexlib.com for the regular expression)
		if (preg_match('/((25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9])\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9])):([0-9]{3,5})/', $sessionId)) {
			// Direct ip:port found
			$selfInstance->debugOutput('HUB-TOOLS: Direct ip:port ' . $sessionId . ' detected.');
		} elseif (isset($selfInstance->sessionIdCache[$sessionId])) {
			// Debug message
			$selfInstance->debugOutput('HUB-TOOLS: Using entry from sessionIdCache[] array.');

			// Found in cache!
			$recipient = $selfInstance->sessionIdCache[$sessionId];

			// Debug message
			$selfInstance->debugOutput('HUB-TOOLS: sessionIdCache[' . $sessionId . ']=' . $recipient);
		} elseif (preg_match('/([a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,6}:([0-9]{3,5})/', $sessionId)) {
			// Hostname:port found
			$selfInstance->debugOutput('HUB-TOOLS: hostname:port ' . $sessionId . ' detected.');

			// Hostname:port found
			$hostnameArray = explode(':', $sessionId);

			// Try to resolve it and add port again
			// @TODO Please try to encapsulate this PHP call into an own class
			$recipient = gethostbyname($hostnameArray[0]) . ':' . $hostnameArray[1];

			// Is it valid?
			if ($recipient == $sessionId) {
				// Resolving hostname->IP failed!
				throw new NoValidHostnameException($hostnameArray, self::EXCEPTION_HOSTNAME_NOT_FOUND);
			} // END - if

			// Debug message
			$selfInstance->debugOutput('HUB-TOOLS: hostname:port ' . $sessionId . ' resolved to ' . $recipient);
		} elseif (preg_match('/([a-f0-9]{' . $selfInstance->getSessionIdLength() . '})/', $sessionId)) {
			// Debug message
			$selfInstance->debugOutput('HUB-TOOLS: Using internal session id resolver.');

			// Resolve session id into a ip:port combination
			$recipient = $selfInstance->resolveIpPortBySessionId($sessionId, $protocol);

			// Debug message
			$selfInstance->debugOutput('HUB-TOOLS: session id ' . $sessionId . ' resolved to ' . $recipient);
		} else {
			// Invalid session id
			throw new InvalidSessionIdException($sessionId, self::EXCEPTION_SESSION_ID_IS_INVALID);
		}

		// Return it
		return $recipient;
	}

	/**
	 * Determine IP or 'external_ip' if set
	 *
	 * @return	$ip		The determined external ip of this node
	 */
	public static function determineOwnExternalIp () {
		// Is the external_ip config entry set?
		if (FrameworkConfiguration::getSelfInstance()->getConfigEntry('external_ip') != '') {
			// Use it as external ip
			$ip = FrameworkConfiguration::getSelfInstance()->getConfigEntry('external_ip');
		} else {
			// Determine own external ip by connecting to my (coder) server at 188.138.90.169
			$ip = ConsoleTools::determineExternalIp();
		}

		// Return it
		return $ip;
	}
}

// [EOF]
?>