<?php
/**
 * The hub's main loop. The hub will wait and listen for incoming requests in
 * this loop.
 *
 * @author		Roland Haeder <webmaster@ship-simu.org>
 * @version		0.0
 * @copyright	Copyright(c) 2007, 2008 Roland Haeder, this is free software
 * @license		GNU GPL 3.0 or any newer version
 *
 * 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 HubCoreLoop extends BaseFrameworkSystem {
	/**
	 * Wether the hub is active and running
	 */
	private $hubActivated = false;

	/**
	 * Wether the hub is shutting down
	 */
	private $hubShutsDown = false;

	/**
	 * A list of all connected peers (sockets)
	 */
	private $connectedPeers = null;

	/**
	 * A console output handler
	 */
	private $outputInstance = null;

	/**
	 * Reading peers
	 */
	private $readPeers = array();

	/**
	 * Writing peers
	 */
	private $writePeers = array();

	/**
	 * The main socket (listening) for this hub
	 */
	private $main_socket = null;

	/**
	 * A list of authenticated peers
	 */
	private $authPeers = null;

	/**
	 * Last peer instance
	 */
	private $lastPeerInstance = null;

	/**
	 * Wether this hub is a master hub
	 */
	private $hubIsMaster = false;

	/**
	 * Maximum auth retries (cached)
	 */
	private $authRetries = 0;

	/**
	 * Auth request message
	 */
	private $authRequest = "";

	/**
	 * Cached timeout for auth requests
	 */
	private $authRequestTimeout = 0;

	/**
	 * An instance to the HubConnector class for master hub connection
	 */
	private $masterConnector = null;

	// Exception codes
	const EXCEPTION_SOCKET_PROBLEM			= 0xb00;
	const EXCEPTION_HUB_PEER_TIMEOUT		= 0xb01;
	const EXCEPTION_HUB_PEER_FAILED_AUTH	= 0xb02;
	const EXCEPTION_HELLO_TIMED_OUT			= 0xb03;

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

		// Set description
		$this->setObjectDescription("Hub-Core Loop");

		// Set unique ID
		$this->generateUniqueId();

		// Tidy up a little
		$this->removeSystemArray();
		$this->removeNumberFormaters();

		// Init the peer list
		$this->initPeerList();
	}

	/**
	 * Factory for main loop
	 *
	 * @return	$hubInstance		An instance of this class
	 */
	public final static function createHubCoreLoop () {
		// Get an instance
		$hubInstance = new HubCoreLoop();

		// Try to setup the socket
		$hubInstance->setupHub();

		// Get the configuration variable
		$outEngine = $hubInstance->getConfigInstance()->readConfig("tpl_engine");

		// Setup the console output handler
		$eval = sprintf("\$hubInstance->setOutputInstance(%s::create%s(\"%s\"));",
			$outEngine,
			$outEngine,
			$hubInstance->getConfigInstance()->readConfig("web_content_type")
		);

		// Debug message
		if ((defined('DEBUG_EVAL')) || (defined('DEBUG_ALL'))) $hubInstance->getDebugInstance()->output(sprintf("[%s:] Konstruierte PHP-Anweisung: %s",
			$hubInstance->__toString(),
			htmlentities($eval)
		));
		@eval($eval);

		// Return the prepared instance
		return $hubInstance;
	}

	/**
	 * Initializes the peer list
	 *
	 * @return	void
	 */
	private final function initPeerList () {
		$this->connectedPeers = new FrameworkArrayObject("FakedConnectedPeers");
		$this->authPeers      = new FrameworkArrayObject("FakeAuthPeers");
	}

	/**
	 * Get total number of connected peers
	 *
	 * @return	$num		The total number of connected peers
	 */
	private final function getTotalConnectedPeers () {
		$read = array($this->connectedPeers->getIterator()->current());
		$write = array();
		$except = array();

		// Get socket number
		$num = socket_select(
			$read,
			$write,
			$except,
			0
		);

		// Transfer readers and writers
		$this->readPeers	= $read;
		$this->writePeers	= $write;

		// Return the number
		return $num;
	}

	/**
	 * Handle newly connected peers
	 *
	 * @return	void
	 */
	private final function handleNewPeers () {
		// Output message
		$this->getOutputInstance()->output(sprintf("[%s] Validating peer...", __METHOD__));

		// Is the main socket in the array?
		if (in_array($this->main_socket, $this->readPeers)) {
			// Accept the connection and add him to the list
			$peer_socket = socket_accept($this->main_socket);

			// Get a new peer instance
			$this->setCurrPeerInstance(HubPeer::createHubPeerBySocket($peer_socket, $this));

			// Register the new peer
			$this->getOutputInstance()->output(sprintf("[%s] Registering new peer with IP %s.",
				__METHOD__,
				$this->getCurrPeerInstance()->getValidatedIP()
			));
			$this->connectedPeers->append($this->lastPeerInstance);

			// A new peer has connected
			$this->getOutputInstance()->output(sprintf("[%s] New peer with IP %s has been registered.",
				__METHOD__,
				$this->getCurrPeerInstance()->getValidatedIP()
			));

			// Remove him from the list
			$key = array_search($this->main_socket, $this->readPeers);
			unset($this->readPeers[$key]);
		} // END - if
	}

	/**
	 * Handles unauthenticated peers
	 *
	 * @return	void
	 * @throws	HubPeerTimeoutException			If the peer times out to answer a request
	 * @throws	HubPeerAuthorizationException		If the peer fails to authorize himself (to many retries)
	 */
	private final function handleUnauthPeers () {
		// Are there some peers?
		if ($this->connectedPeers->count() > 1) {
			// Iterate through all connected peers
			for ($idx = $this->connectedPeers->getIterator(); $idx->valid(); $idx->next()) {
				// Get current peer
				$this->lastPeerInstance = $idx->current();

				// Ignore own socket and invalid entries
				if (($this->getCurrPeerInstance() !== $this->main_socket) && (is_object($this->getCurrPeerInstance())) && ($this->getCurrPeerInstance() instanceof HubPeer)) {
					// Is this peer already authorized or is this the master hub?
					// If this is the master hub then there is no auth required
					if ((!$this->getCurrPeerInstance()->ifPeerIsAuthorized()) && (!$this->getCurrPeerInstance()->ifPeerIsLocalAdmin()) && (!$this->hubIsMaster)) {
						// This peer waits for authorization, so does he have some tries left?
						if ($this->getCurrPeerInstance()->getAuthRetries() <= $this->authRetries) {
							// This peer is still allowed to try his authorization
							if ($this->getCurrPeerInstance()->getLastSentMessage() == $this->authRequest) {
								// Already asked so maybe timed out?
								if ((time() - $this->getCurrPeerInstance()->getLastSentMessageStamp()) >= $this->authRequestTimeout) {
									// Timed out so disconnect the peer
									throw new HubPeerTimeoutException (
										array(
											'this'	=> $this,
											'peer'	=> $this->getCurrPeerInstance()
										), self::EXCEPTION_HUB_PEER_TIMEOUT
									);
								} // END - if
							} elseif ($this->getCurrPeerInstance()->ifHelloReceived()) {
								// HELLO received so we need to sent the AUTH request
								$this->getCurrPeerInstance()->askAuthorizationKey();
							}
						} else {
							// This peer needs disconnecting!
							throw new HubPeerAuthorizationException (
								array(
									'this'	=> $this,
									'peer'	=> $this->getCurrPeerInstance(),
									'max'	=> $this->authRetries
								), self::EXCEPTION_HUB_PEER_FAILED_AUTH
							);
						} // END - else
					} elseif ((!$this->getCurrPeerInstance()->ifPeerIsAuthorized()) && ($this->getCurrPeerInstance()->ifPeerIsLocalAdmin())) {
						// This peer is a local admin so he is always authorized!
						$this->getCurrPeerInstance()->enableLocalAdmin();

						// Output debug message
						$this->getOutputInstance()->output(sprintf("[%s] A local admin has connected.",
							$this->__toString()
						));

						// Say "hi" to the admin
						$this->getCurrPeerInstance()->sayHi2Admin();
					} elseif (($this->hubIsMaster) && ($this->getCurrPeerInstance()->ifHelloReceived()) && (!$this->getCurrPeerInstance()->ifELHOsent())) {
						// Is the master hub so authorize the peer here...
						$this->getCurrPeerInstance()->enableIsAuthorized();
						$this->authPeers->append($this->getCurrPeerInstance());

						// Reply the HELLO request
						$this->getCurrPeerInstance()->replyHelloMessage();
					}
				} // END - if
			} // END - for
		} // END - if
	}

	/**
	 * Handles only authorized peers
	 *
	 * @return	void
	 */
	public function handleAuthPeers () {
		// Are there some peers?
		if (($this->connectedPeers->count() > 1) && ($this->authPeers->count() > 0)) {
			// Iterate through all connected peers
			for ($idx = $this->authPeers->getIterator(); $idx->valid(); $idx->next()) {
				// Get current peer
				$this->lastPeerInstance = $idx->current();

				// Do the ping and update our authPeer list (LATER!)
				$this->lastPeerInstance->handlePingPeer();

				// Avoids a notice...
				if (is_null($this->getCurrPeerInstance())) break;
			} // END - for
		} // END - for
	}

	/**
	 * Setup the hub: Create a socket for listening on incoming requests,
	 * try to bind to a port, etc.
	 *
	 * @return	void
	 * @throws	SocketCreationException		If a socket cannot be created
	 * @throws	SocketSetupException		If a socket cannot be setuped
	 * @throws	SocketBindException			If a socket cannot be bind to
	 *									an address and port
	 * @throws	SocketListeningException		If listening to a socket fails
	 */
	private final function setupHub () {
		// Create a new TCP socket
		$main_socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);

		// Was it a success?
		if (!is_resource($main_socket)) {
			// This fails! :(
			throw new SocketCreationException(
				array(
					'this' => $this,
					'code' => socket_last_error()
				), self::EXCEPTION_SOCKET_PROBLEM
			);
		}

		// Set socket options
		if (!socket_set_option($main_socket, SOL_SOCKET, SO_REUSEADDR, 1)) {
			// Close the socket
			$this->closeSocket($main_socket);

			// Problems setting socket options
			throw new SocketSetupException (
				array(
					'this' => $this,
					'code' => socket_last_error()
				), self::EXCEPTION_SOCKET_PROBLEM
			);
		}

		// Set to non-blocking
		socket_set_nonblock($main_socket);

		// Bind the socket to an address
		if (!socket_bind($main_socket, $this->getConfigInstance()->readConfig("hub_listen_addr"), $this->getConfigInstance()->readConfig("hub_listen_port"))) {
			// Bind failed
			throw new SocketBindException (
				array(
					'this' => $this,
					'host' => $this->getConfigInstance()->readConfig("hub_listen_addr"),
					'port' => $this->getConfigInstance()->readConfig("hub_listen_port"),
					'code' => socket_last_error()
				), self::EXCEPTION_SOCKET_PROBLEM
			);
		}

		// Listen to ... the socket ;-)
		if (!socket_listen($main_socket)) {
			// Opps, that didn't work. Next time better listen to your heart... Roxette
			throw new SocketListeningException(
				array(
					'this' => $this,
					'code' => socket_last_error()
				), self::EXCEPTION_SOCKET_PROBLEM
			);
		}

		// Ignore user abort and do not time out
		@set_time_limit(0);
		@ignore_user_abort(true);

		// Cache more configuration stuff
		$this->authRetries        = $this->getConfigInstance()->readConfig("hub_max_auth_tries");
		$this->authRequest        = $this->getConfigInstance()->readConfig("hub_auth_request");
		$this->authRequestTimeout = $this->getConfigInstance()->readConfig("hub_auth_request_timeout");

		// The hub is running now!
		$this->hubActivated = true;

		// Append the main hub
		$this->main_socket = $main_socket;
		$this->connectedPeers->append($main_socket);
	}

	/**
	 * Removes the current peer from the list
	 *
	 * @return	void
	 */
	public final function removePeerFromConnectList () {
		// Iterate through all connected peers
		for ($idx = $this->connectedPeers->getIterator(); $idx->valid(); $idx->next()) {
			// Get current peer from list
			$peer = $idx->current();

			// Is it a peer instance?
			if (($peer !== $this->main_socket) && (is_object($peer)) && ($peer instanceof HubPeer)) {
				// Okay, we have a peer instance so is it the same?
				if ($this->getCurrPeerInstance()->equals($peer)) {
					// Remove him!
					$idx->offsetUnset($idx->key());

					// Remove the last instance as well
					$this->lastPeerInstance = null;

					// Remove the socket as well
					$this->removeSocket($peer);

					// Stop searching here
					break;
				}
			}
		}
	}

	/**
	 * Getter for console output handler
	 *
	 * @return	$outputInstance	An instance of the output handler
	 */
	public final function getOutputInstance () {
		return $this->outputInstance;
	}

	/**
	 * Setter for console output handler
	 *
	 * @param		$outputInstance	An instance of the output handler
	 */
	public final function setOutputInstance ($outputInstance) {
		$this->outputInstance = $outputInstance;
	}

	/**
	 * Getter for current peer instance to HubPeer class
	 *
	 * @return	$lastPeerInstance		Last peer instance
	 */
	public final function getCurrPeerInstance () {
		return $this->lastPeerInstance;
	}

	/**
	 * Setter for current peer instance to HubPeer class
	 *
	 * @param		$lastPeerInstance		Last peer instance
	 * @return	void
	 */
	public final function setCurrPeerInstance (HubPeer $lastPeerInstance) {
		$this->lastPeerInstance = $lastPeerInstance;
	}

	/**
	 * Checks wether the hub is running and not in shutdown phase
	 *
	 * @return	$isRunning	If the hub is running and not in shutdown phase
	 */
	public function ifHubIsRunning () {
		return ((($this->hubActivated) || (!$this->hubShutsDown)) && ($this->connectedPeers->count() > 0));
	}

	/**
	 * Output the intro text
	 *
	 * @return	void
	 */
	public final function outputIntro () {
		if ($this->getConfigInstance()->readConfig("hub_intro_enabled") == "Y") {
			// Output intro text
			$this->getOutputInstance()->output(sprintf("%s v%s Copyright (c) 2007, 2008 by Roland H&auml;der",
				ApplicationHelper::getInstance()->getAppName(),
				ApplicationHelper::getInstance()->getAppVersion()
			));
			$this->getOutputInstance()->output("");
			$this->getOutputInstance()->output("This software is free software licensed under the GNU GPL. In telnet session enter &quot;/license&quot; to read the license.");
			$this->getOutputInstance()->output("This software uses the MXChange Framework, Copyright (c) 2007, 2008 by Roland H&auml;der which is licensed under the GNU GPL.");
			$this->getOutputInstance()->output("Enter &quot;/framework&quot; in telnet session to read that license.");
			$this->getOutputInstance()->output("");
			$this->getOutputInstance()->output("All core systems are initialized. Input on *this* console will currently be ignored!");
			$this->getOutputInstance()->output("");
			$this->getOutputInstance()->output(sprintf("[%s] Listening on: %s:%d",
				$this->__toString(),
				$this->getConfigInstance()->readConfig("hub_listen_addr"),
				$this->getConfigInstance()->readConfig("hub_listen_port")
			));
			$this->getOutputInstance()->output("----------------------------------------------------------------------------------------------------------------------------");
		}
	}

	/**
		* Do the main loop
		*
		* @return	void
		* @throws	SocketCreationException		If the main socket is not a resource
		*/
	 public function coreLoop () {
	 	// Is the main socket vailid?
		if (!is_resource($this->main_socket)) {
			// Is not valid!
			throw new SocketCreationException(
				array(
					'this'	=> $this,
					'code'	=> socket_last_error()
				), self::EXCEPTION_SOCKET_PROBLEM
			);
		} // END - if

		// We are ready to serve requests
		$this->getOutputInstance()->output(sprintf("[%s] Ready to serve requests.",
			$this->__toString()
		));

	 	// Wait until the hub is shutting down
		while ($this->ifHubIsRunning()) {
			// Get number of total connected peers
			$num = $this->getTotalConnectedPeers();

			try {
				// Handle the master hub connection
				if ($this->masterConnector instanceof HubConnector) {
					$this->masterConnector->handleMasterRequests();
				}

				// Check for unauthorized peers
				$this->handleUnauthPeers();

				// Handle authorized peers
				$this->handleAuthPeers();
			} catch (HubPeerAuthorizationException $e) {
				// Authorization has failed
				$this->disconnectPeerWithReason("hub_msg_auth_tries");

				// Get new total connected peers
				$num = $this->getTotalConnectedPeers();
			} catch (HubPeerTimeoutException $e) {
				// Disconnect and remove the peer
				$this->disconnectPeerWithReason("hub_msg_auth_reply_timeout");

				// Get new total connected peers
				$num = $this->getTotalConnectedPeers();
			} catch (HubMasterDisconnectedException $e) {
				// The master hub has disconnected us... :(
				$this->masterConnector = null;
				$this->getOutputInstance()->output(sprintf("[%s] The master has disconnected us. Reason given: %s",
					$this->__toString(),
					$e->getMessage()
				));

				// Get new total connected peers
				$num = $this->getTotalConnectedPeers();
			} catch (BrokenPipeException $e) {
				// Broken pipes are bad for us... :(
				$this->removePeerFromConnectList();
				$this->getOutputInstance()->output(sprintf("[%s] A peer has closed the connection unexpected: %s",
					$this->__toString(),
					$e->getMessage()
				));

				// Get new total connected peers
				$num = $this->getTotalConnectedPeers();
			} catch (FrameworkException $e) {
				// Catch all other exceptions and output them
				hub_exception_handler($e);

				// Get new total connected peers
				$num = $this->getTotalConnectedPeers();
			}

			// Are there some peers?
			if ($num < 1) {
				// Wait for more peers
				continue;
			} // END - if

			// A new peer has connected
			$this->getOutputInstance()->output(sprintf("[%s] A new peer is connecting.",
				$this->__toString()
			));

			try {
				// Check for new peers
				$this->handleNewPeers();
			} catch (IPSpoofingException $e) {
				// Output message
				$this->getOutputInstance()->output(sprintf("[%s] The peer's IP number has changed!",
					$this->__toString()
				));

				// Output debug message
				$this->getDebugInstance()->output(sprintf("[%s] Peer spoofes IP number: %s",
					$this->__toString(),
					$e->getMessage()
				));

				// Disconnect the peer first
				$this->disconnectPeerWithReason("hub_msg_spoofing");

				// Get new total connected peers
				$num = $this->getTotalConnectedPeers();
			} catch (FrameworkException $e) {
				// Catch all exceptions and output them to avoid aborting the program unexpectly
				hub_exception_handler($e);

				// Get new total connected peers
				$num = $this->getTotalConnectedPeers();
			}

		} // END - while
	}

	/**
	 * Tries to contact the master server or simply reports that we are the master server
	 *
	 * @return	void
	 */
	public function contactMasterHub () {
		// Checks wether we are the master hub
		if ($_SERVER['SERVER_ADDR'] == $this->getConfigInstance()->readConfig("hub_master_ip")) {
			// We are master!
			$this->hubIsMaster = true;
			$this->getOutputInstance()->output(sprintf("[%s] Our IP %s matches the master IP. Becoming master hub...",
				$this->__toString(),
				$_SERVER['SERVER_ADDR']
			));
		} else {
			// A regular hub or ultra hub so let's contact the master
			$this->getOutputInstance()->output(sprintf("[%s] Contacting the master hub at %s:%d...",
				$this->__toString(),
				$this->getConfigInstance()->readConfig("hub_master_ip"),
				$this->getConfigInstance()->readConfig("hub_master_port")
			));

			// Try to aquire a connection to the master...
			try {
				// Announce us to the master hub
				$this->announceToMasterHub();
			} catch (FrameworkException $e) {
				// Catch all exceptions and output them
				hub_exception_handler($e);
			}
		} // END - else
	}

	/**
	 * Disconnects the current with a configurable reason
	 *
	 * @param		$reasonEntry	The entry with the disconnection reason aka. message to the peer
	 * @return	void
	 */
	 public function disconnectPeerWithReason ($reasonEntry) {
	 	// Default is that we cannot read the peer's IP number
	 	$ip = "0.0.0.0";

	 	// Try to disconnect here
		try {
		 	// First get the raw IP number
			$ip = $this->getCurrPeerInstance()->getValidatedIP();

		 	// Disconnect the peer...
		 	$this->getCurrPeerInstance()->disconnectWithReason($this->getConfigInstance()->readConfig($reasonEntry));
		} catch (FrameworkException $e) {
			// Catch all exceptions and output them
			hub_exception_handler($e);
		}

		// Remove him from the list anyway
		$this->removePeerFromConnectList();

		// Output the message
		$this->getOutputInstance()->output(sprintf("[%s] Peer %s has been disconnected.",
			$this->__toString(),
			$ip
		));
	}

	/**
	 * Announces this hub to the master hub. This is being done by connecting to it and asking for auth request
	 *
	 * @return	void
	 */
	public function announceToMasterHub () {
		try {
			// Create a new instance for communicating to the master hub
			$this->masterConnector = HubConnector::createHubConnectorByAddressPort(
				$this->getConfigInstance()->readConfig("hub_master_ip"),
				$this->getConfigInstance()->readConfig("hub_master_port"),
				$this
			);

			// Send all our accepted objects to the master hub
			$this->masterConnector->sendAllAcceptedObjects();
		} catch (SocketConnectException $e) {
			// The master hub is down!
			ApplicationEntryPoint::app_die($e->getMessage());
		}
	}

	/**
	 * Removes a given peer instance (socket) from all lists
	 *
	 * @param	$peerInstance		An instance of a HubPeer class
	 * @return	void
	 */
	private function removeSocket (HubPeer $peerInstance) {
		// Get socket from peer
		$socket = $peerInstance->getPeerSocket();

		// Search for readers
		$key = array_search($socket, $this->readPeers, true);
		if ($key !== false) {
			// Remove from reader list
			unset($this->readPeers[$key]);
		}

		// Search for writers
		$key = array_search($socket, $this->writePeers, true);
		if ($key !== false) {
			// Remove from writer list
			unset($this->writePeers[$key]);
		}

		// Remove from auth peers as well
		for ($idx = $this->authPeers->getIterator(); $idx->valid(); $idx->next()) {
			// Get current entry
			$current = $idx->current();

			// Is it the same?
			if ($current->equals($peerInstance)) {
				// Remove from auth (-awaiting) list
				$idx->offsetUnset($idx->key());
				break;
			}
		}
	}

} // END - class

// [EOF]
?>