<?php
// Own namespace
namespace CoreFramework\Listener;

// Import framework stuff
use CoreFramework\Factory\ObjectFactory;
use CoreFramework\Object\BaseFrameworkSystem;

/**
 * A general listener class
 *
 * @author		Roland Haeder <webmaster@shipsimu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2017 Core Developer Team
 * @license		GNU GPL 3.0 or any newer version
 * @link		http://www.shipsimu.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 BaseListener extends BaseFrameworkSystem implements Visitable {
	// Exception code constants
	const EXCEPTION_INVALID_SOCKET                   = 0xa00;
	const EXCEPTION_SOCKET_ALREADY_REGISTERED        = 0xa01;
	const EXCEPTION_SOCKET_CREATION_FAILED           = 0xa02;
	const EXCEPTION_NO_SOCKET_ERROR                  = 0xa03;
	const EXCEPTION_CONNECTION_ALREADY_REGISTERED    = 0xa04;
	const EXCEPTION_UNEXPECTED_PACKAGE_STATUS        = 0xa05;
	const EXCEPTION_UNSUPPORTED_PACKAGE_CODE_HANDLER = 0xa06;
	const EXCEPTION_FINAL_CHUNK_VERIFICATION         = 0xa07;
	const EXCEPTION_INVALID_DATA_CHECKSUM            = 0xa08;

	/**
	 * Address (IP mostly) we shall listen on
	 */
	private $listenAddress = '0.0.0.0'; // This is the default and listens on all interfaces

	/**
	 * Port we shall listen on (or wait for incoming data)
	 */
	private $listenPort = 0; // This port MUST be changed by your application

	/**
	 * Whether we are in blocking or non-blocking mode (default: non-blocking
	 */
	private $blockingMode = FALSE;

	/**
	 * A peer pool instance
	 */
	private $poolInstance = NULL;

	/**
	 * Protected constructor
	 *
	 * @param	$className	Name of the class
	 * @return	void
	 */
	protected function __construct ($className) {
		// Call parent constructor
		parent::__construct($className);
	}

	/**
	 * Checks whether the given socket resource is a server socket
	 *
	 * @param	$socketResource		A valid socket resource
	 * @return	$isServerSocket		Whether the socket resource is a server socket
	 */
	protected function isServerSocketResource ($socketResource) {
		// Check it
		$isServerSocket = ((is_resource($socketResource)) && (!@socket_getpeername($socketResource, $peerName)));

		// We need to clear the error here if it is a resource
		if ($isServerSocket === TRUE) {
			// Clear the error
			//* DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('socketResource[]=' . gettype($socketResource));
			socket_clear_error($socketResource);
		} // END - if

		// Check peer name, it must be empty
		$isServerSocket = (($isServerSocket) && (empty($peerName)));

		// Return result
		return $isServerSocket;
	}

	/**
	 * Setter for listen address
	 *
	 * @param	$listenAddress	The address this listener should listen on
	 * @return	void
	 */
	protected final function setListenAddress ($listenAddress) {
		$this->listenAddress = (string) $listenAddress;
	}

	/**
	 * Getter for listen address
	 *
	 * @return	$listenAddress	The address this listener should listen on
	 */
	public final function getListenAddress () {
		return $this->listenAddress;
	}

	/**
	 * Setter for listen port
	 *
	 * @param	$listenPort		The port this listener should listen on
	 * @return	void
	 */
	protected final function setListenPort ($listenPort) {
		$this->listenPort = (int) $listenPort;
	}

	/**
	 * Getter for listen port
	 *
	 * @return	$listenPort		The port this listener should listen on
	 */
	public final function getListenPort () {
		return $this->listenPort;
	}

	/**
	 * "Setter" to set listen address from configuration entry
	 *
	 * @param	$configEntry	The configuration entry holding our listen address
	 * @return	void
	 */
	public final function setListenAddressByConfiguration ($configEntry) {
		$this->setListenAddress($this->getConfigInstance()->getConfigEntry($configEntry));
	}

	/**
	 * "Setter" to set listen port from configuration entry
	 *
	 * @param	$configEntry	The configuration entry holding our listen port
	 * @return	void
	 */
	public final function setListenPortByConfiguration ($configEntry) {
		$this->setListenPort($this->getConfigInstance()->getConfigEntry($configEntry));
	}

	/**
	 * Setter for blocking-mode
	 *
	 * @param	$blockingMode	Whether blocking-mode is disabled (default) or enabled
	 * @return	void
	 */
	protected final function setBlockingMode ($blockingMode) {
		$this->blockingMode = (boolean) $blockingMode;
	}

	/**
	 * Checks whether blocking-mode is enabled or disabled
	 *
	 * @return	$blockingMode	Whether blocking mode is disabled or enabled
	 */
	public final function isBlockingModeEnabled () {
		return $this->blockingMode;
	}

	/**
	 * Setter for peer pool instance
	 *
	 * @param	$poolInstance	The peer pool instance we shall set
	 * @return	void
	 */
	protected final function setPoolInstance (PoolablePeer $poolInstance) {
		$this->poolInstance = $poolInstance;
	}

	/**
	 * Getter for peer pool instance
	 *
	 * @return	$poolInstance	The peer pool instance we shall set
	 */
	public final function getPoolInstance () {
		return $this->poolInstance;
	}

	/**
	 * Getter for connection type
	 *
	 * @return	$connectionType		Connection type for this listener
	 */
	public final function getConnectionType () {
		// Wrap the real getter
		return $this->getProtocolName();
	}

	/**
	 * Registeres the given socket resource for "this" listener instance. This
	 * will be done in a seperate class to allow package writers to use it
	 * again.
	 *
	 * @param	$socketResource		A valid server socket resource
	 * @return	void
	 * @throws	InvalidServerSocketException		If the given resource is no server socket
	 * @throws	SocketAlreadyRegisteredException	If the given resource is already registered
	 */
	protected function registerServerSocketResource ($socketResource) {
		// First check if it is valid
		if (!$this->isServerSocketResource($socketResource)) {
			// No server socket
			throw new InvalidServerSocketException(array($this, $socketResource), self::EXCEPTION_INVALID_SOCKET);
		} elseif ($this->isServerSocketRegistered($socketResource)) {
			// Already registered
			throw new SocketAlreadyRegisteredException($this, self::EXCEPTION_SOCKET_ALREADY_REGISTERED);
		}

		// Get a socket registry instance (singleton)
		$registryInstance = SocketRegistryFactory::createSocketRegistryInstance();

		// Get a connection info instance
		$infoInstance = ConnectionInfoFactory::createConnectionInfoInstance($this->getProtocolName(), 'listener');

		// Will the info instance with listener data
		$infoInstance->fillWithListenerInformation($this);

		// Register the socket
		$registryInstance->registerSocket($infoInstance, $socketResource);

		// And set it here
		$this->setSocketResource($socketResource);
	}

	/**
	 * Checks whether given socket resource is registered in socket registry
	 *
	 * @param	$socketResource		A valid server socket resource
	 * @return	$isRegistered		Whether given server socket is registered
	 */
	protected function isServerSocketRegistered ($socketResource) {
		// Get a socket registry instance (singleton)
		$registryInstance = SocketRegistryFactory::createSocketRegistryInstance();

		// Get a connection info instance
		$infoInstance = ConnectionInfoFactory::createConnectionInfoInstance($this->getProtocolName(), 'listener');

		// Will the info instance with listener data
		$infoInstance->fillWithListenerInformation($this);

		// Check it
		$isRegistered = $registryInstance->isSocketRegistered($infoInstance, $socketResource);

		// Return result
		return $isRegistered;
	}

	/**
	 * Accepts the visitor to process the visit "request"
	 *
	 * @param	$visitorInstance	An instance of a Visitor class
	 * @return	void
	 */
	public function accept (Visitor $visitorInstance) {
		// Debug message
		//* DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(strtoupper($this->getProtocolName()) . '-LISTENER[' . __METHOD__ . ':' . __LINE__ . ']: ' . $visitorInstance->__toString() . ' has visited ' . $this->__toString() . ' - CALLED!');

		// Visit this listener
		$visitorInstance->visitListener($this);

		// Visit the pool if set
		if ($this->getPoolInstance() instanceof Poolable) {
			$this->getPoolInstance()->accept($visitorInstance);
		} // END - if

		// Debug message
		//* DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(strtoupper($this->getProtocolName()) . '-LISTENER[' . __METHOD__ . ':' . __LINE__ . ']: ' . $visitorInstance->__toString() . ' has visited ' . $this->__toString() . ' - EXIT!');
	}

	/**
	 * Monitors incoming raw data from the handler and transfers it to the
	 * given receiver instance. This method should not be called, please call
	 * the decorator's version instead to separator node/client traffic.
	 *
	 * @return	void
	 * @throws	UnsupportedOperatorException	If this method is called by a mistake
	 */
	public function monitorIncomingRawData () {
		throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
	}

	/**
	 * Constructs a callable method name from given socket error code. If the
	 * method is not found, a generic one is used.
	 *
	 * @param	$errorCode		Error code from socket_last_error()
	 * @return	$handlerName	Call-back method name for the error handler
	 * @throws	UnsupportedSocketErrorHandlerException If the error handler is not implemented
	 */
	protected function getSocketErrorHandlerFromCode ($errorCode) {
		// Create a name from translated error code
		$handlerName = 'socketError' . self::convertToClassName($this->translateSocketErrorCodeToName($errorCode)) . 'Handler';

		// Is the call-back method there?
		if (!method_exists($this, $handlerName)) {
			// Please implement this
			throw new UnsupportedSocketErrorHandlerException(array($this, $handlerName, $errorCode), BaseConnectionHelper::EXCEPTION_UNSUPPORTED_ERROR_HANDLER);
		} // END - if

		// Return it
		return $handlerName;
	}

	/**
	 * Translates socket error codes into our own internal names which can be
	 * used for call-backs.
	 *
	 * @param	$errorCode	The error code from socket_last_error() to be translated
	 * @return	$errorName	The translated name (all lower-case, with underlines)
	 */
	public function translateSocketErrorCodeToName ($errorCode) {
		// Nothing bad happened by default
		$errorName = BaseRawDataHandler::SOCKET_CONNECTED;

		// Is the code a number, then we have to change it
		switch ($errorCode) {
			case 0: // Silently ignored, the socket is connected
				break;

			case 11:  // "Resource temporary unavailable"
				$errorName = BaseRawDataHandler::SOCKET_ERROR_RESOURCE_UNAVAILABLE;
				break;

			case 13:  // "Permission denied"
				$errorName = BaseRawDataHandler::SOCKET_ERROR_PERMISSION_DENIED;
				break;

			case 32:  // "Broken pipe"
				$errorName = BaseRawDataHandler::SOCKET_ERROR_BROKEN_PIPE;
				break;

			case 104: // "Connection reset by peer"
				$errorName = BaseRawDataHandler::SOCKET_ERROR_CONNECTION_RESET_BY_PEER;
				break;

			case 107: // "Transport end-point not connected"
			case 134: // On some (?) systems for 'transport end-point not connected'
				// @TODO On some systems it is 134, on some 107?
				$errorName = BaseRawDataHandler::SOCKET_ERROR_TRANSPORT_ENDPOINT;
				break;

			case 110: // "Connection timed out"
				$errorName = BaseRawDataHandler::SOCKET_ERROR_CONNECTION_TIMED_OUT;
				break;

			case 111: // "Connection refused"
				$errorName = BaseRawDataHandler::SOCKET_ERROR_CONNECTION_REFUSED;
				break;

			case 113: // "No route to host"
				$errorName = BaseRawDataHandler::SOCKET_ERROR_NO_ROUTE_TO_HOST;
				break;

			case 114: // "Operation already in progress"
				$errorName = BaseRawDataHandler::SOCKET_ERROR_OPERATION_ALREADY_PROGRESS;
				break;

			case 115: // "Operation now in progress"
				$errorName = BaseRawDataHandler::SOCKET_ERROR_OPERATION_IN_PROGRESS;
				break;

			default: // Everything else <> 0
				// Unhandled error code detected, so first debug it because we may want to handle it like the others
				self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-HUB[' . __METHOD__ . ':' . __LINE__ . '] UNKNOWN ERROR CODE = ' . $errorCode . ', MESSAGE = ' . socket_strerror($errorCode));

				// Change it only in this class
				$errorName = BaseRawDataHandler::SOCKET_ERROR_UNKNOWN;
				break;
		}

		// Return translated name
		return $errorName;
	}

	/**
	 * Shuts down a given socket resource. This method does only ease calling
	 * the right visitor.
	 *
	 * @param	$socketResource		A valid socket resource
	 * @return	void
	 */
	public function shutdownSocket ($socketResource) {
		// Debug message
		self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('HUB-SYSTEM: Shutting down socket resource ' . $socketResource . ' with state ' . $this->getPrintableState() . ' ...');

		// Set socket resource
		$this->setSocketResource($socketResource);

		// Get a visitor instance
		$visitorInstance = ObjectFactory::createObjectByConfiguredName('shutdown_socket_visitor_class');

		// Debug output
		self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('HUB-SYSTEM:' . $this->__toString() . ': visitorInstance=' . $visitorInstance->__toString());

		// Call the visitor
		$this->accept($visitorInstance);
	}

	/**
	 * Half-shuts down a given socket resource. This method does only ease calling
	 * an other visitor than shutdownSocket() does.
	 *
	 * @param	$socketResource		A valid socket resource
	 * @return	void
	 */
	public function halfShutdownSocket ($socketResource) {
		// Debug message
		self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('HUB-SYSTEM: Half-shutting down socket resource ' . $socketResource . ' with state ' . $this->getPrintableState() . ' ...');

		// Set socket resource
		$this->setSocketResource($socketResource);

		// Get a visitor instance
		$visitorInstance = ObjectFactory::createObjectByConfiguredName('half_shutdown_socket_visitor_class');

		// Debug output
		self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('HUB-SYSTEM:' . $this->__toString() . ': visitorInstance=' . $visitorInstance->__toString());

		// Call the visitor
		$this->accept($visitorInstance);
	}

	// ************************************************************************
	//                 Socket error handler call-back methods
	// ************************************************************************

	/**
	 * Handles socket error 'permission denied', but does not clear it for
	 * later debugging purposes.
	 *
	 * @param	$socketResource		A valid socket resource
	 * @param	$socketData			A valid socket data array (0 = IP/file name, 1 = port)
	 * @return	void
	 * @throws	SocketBindingException	The socket could not be bind to
	 */
	protected function socketErrorPermissionDeniedHandler ($socketResource, array $socketData) {
		// Get socket error code for verification
		$socketError = socket_last_error($socketResource);

		// Get error message
		$errorMessage = socket_strerror($socketError);

		// Shutdown this socket
		$this->shutdownSocket($socketResource);

		// Throw it again
		throw new SocketBindingException(array($this, $socketData, $socketResource, $socketError, $errorMessage), BaseListener::EXCEPTION_INVALID_SOCKET);
	}

	/**
	 * "Listens" for incoming network packages
	 *
	 * @param	$peerSuffix		Suffix for peer name (e.g. :0 for TCP(/UDP?) connections)
	 * @return	void
	 * @throws	InvalidSocketException	If an invalid socket resource has been found
	 */
	protected function doListenSocketSelect ($peerSuffix) {
		// Check on all instances
		assert($this->getPoolInstance() instanceof Poolable);
		assert(is_resource($this->getSocketResource()));

		// Get all readers
		$readers = $this->getPoolInstance()->getAllSingleSockets();
		$writers = array();
		$excepts = array();

		// Check if we have some peers left
		$left = socket_select(
			$readers,
			$writers,
			$excepts,
			0,
			150
		);

		// Some new peers found?
		if ($left < 1) {
			// Debug message
			//* EXTREME-NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('TCP-LISTENER[' . __METHOD__ . ':' . __LINE__ . ']: left=' . $left . ',serverSocket=' . $this->getSocketResource() . ',readers=' . print_r($readers, TRUE));

			// Nothing new found
			return;
		} // END - if

		// Debug message
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('TCP-LISTENER[' . __METHOD__ . ':' . __LINE__ . ']: serverSocket=' . $this->getSocketResource() . ',readers=' . print_r($readers, TRUE));

		// Do we have changed peers?
		if (in_array($this->getSocketResource(), $readers)) {
			/*
			 * Then accept it, if this socket is set to non-blocking IO and the
			 * connection is NOT sending any data, socket_read() may throw
			 * error 11 (Resource temporary unavailable). This really nasty
			 * because if you have blocking IO socket_read() will wait and wait
			 * and wait ...
			 */
			$newSocket = socket_accept($this->getSocketResource());

			// Debug message
			//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('TCP-LISTENER[' . __METHOD__ . ':' . __LINE__ . ']: newSocket=' . $newSocket . ',serverSocket=' .$this->getSocketResource());

			// Array for timeout settings
			$options  = array(
				// Seconds
				'sec'  => $this->getConfigInstance()->getConfigEntry('tcp_socket_accept_wait_sec'),
				// Milliseconds
				'usec' => $this->getConfigInstance()->getConfigEntry('tcp_socket_accept_wait_usec')
			);

			// Set timeout to configured seconds
			// @TODO Does this work on Windozer boxes???
			if (!socket_set_option($newSocket, SOL_SOCKET, SO_RCVTIMEO, $options)) {
				// Handle this socket error with a faked recipientData array
				$this->handleSocketError(__METHOD__, __LINE__, $newSocket, array('0.0.0.0', '0'));
			} // END - if

			// Output result (only for debugging!)
			/*
			$option = socket_get_option($newSocket, SOL_SOCKET, SO_RCVTIMEO);
			self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('SO_RCVTIMEO[' . gettype($option) . ']=' . print_r($option, TRUE));
			*/

			// Enable SO_OOBINLINE
			if (!socket_set_option($newSocket, SOL_SOCKET, SO_OOBINLINE ,1)) {
				// Handle this socket error with a faked recipientData array
				$this->handleSocketError(__METHOD__, __LINE__, $newSocket, array('0.0.0.0', '0'));
			} // END - if

			// Set non-blocking
			if (!socket_set_nonblock($newSocket)) {
				// Handle this socket error with a faked recipientData array
				$this->handleSocketError(__METHOD__, __LINE__, $newSocket, array('0.0.0.0', '0'));
			} // END - if

			// Add it to the peers
			$this->getPoolInstance()->addPeer($newSocket, BaseConnectionHelper::CONNECTION_TYPE_INCOMING);

			// Get peer name
			if (!socket_getpeername($newSocket, $peerName)) {
				// Handle this socket error with a faked recipientData array
				$this->handleSocketError(__METHOD__, __LINE__, $newSocket, array('0.0.0.0', '0'));
			} // END - if

			// Get node instance
			$nodeInstance = NodeObjectFactory::createNodeInstance();

			// Create a faked package data array
			$packageData = array(
				NetworkPackage::PACKAGE_DATA_SENDER    => $peerName . $peerSuffix,
				NetworkPackage::PACKAGE_DATA_RECIPIENT => $nodeInstance->getSessionId(),
				NetworkPackage::PACKAGE_DATA_STATUS    => NetworkPackage::PACKAGE_STATUS_FAKED
			);

			// Get a connection info instance
			$infoInstance = ConnectionInfoFactory::createConnectionInfoInstance($this->getProtocolName(), 'listener');

			// Will the info instance with listener data
			$infoInstance->fillWithListenerInformation($this);

			// Get a socket registry
			$registryInstance = SocketRegistryFactory::createSocketRegistryInstance();

			// Register the socket with the registry and with the faked array
			$registryInstance->registerSocket($infoInstance, $newSocket, $packageData);
		} // END - if

		// Do we have to rewind?
		if (!$this->getIteratorInstance()->valid()) {
			// Rewind the list
			$this->getIteratorInstance()->rewind();
		} // END - if

		// Get the current value
		$currentSocket = $this->getIteratorInstance()->current();

		// Handle it here, if not main server socket
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('TCP-LISTENER[' . __METHOD__ . ':' . __LINE__ . ']: currentSocket=' . $currentSocket[BasePool::SOCKET_ARRAY_RESOURCE] . ',type=' . $currentSocket[BasePool::SOCKET_ARRAY_CONN_TYPE] . ',serverSocket=' . $this->getSocketResource());
		if (($currentSocket[BasePool::SOCKET_ARRAY_CONN_TYPE] != BaseConnectionHelper::CONNECTION_TYPE_SERVER) && ($currentSocket[BasePool::SOCKET_ARRAY_RESOURCE] != $this->getSocketResource())) {
			// ... or else it will raise warnings like 'Transport endpoint is not connected'
			$this->getHandlerInstance()->processRawDataFromResource($currentSocket);
		} // END - if

		// Advance to next entry. This should be the last line.
		$this->getIteratorInstance()->next();
	}

}