<?php
/**
 * An UDP connection listener
 *
 * @author		Roland Haeder <webmaster@ship-simu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2011 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 UdpListener extends BaseListener implements Listenable {
	/**
	 * Protected constructor
	 *
	 * @return	void
	 */
	protected function __construct () {
		// Call parent constructor
		parent::__construct(__CLASS__);
	}

	/**
	 * Creates an instance of this class
	 *
	 * @param	$nodeInstance		A NodeHelper instance
	 * @return	$listenerInstance	An instance a prepared listener class
	 */
	public static final function createUdpListener (NodeHelper $nodeInstance) {
		// Get new instance
		$listenerInstance = new UdpListener();

		// Set the application instance
		$listenerInstance->setNodeInstance($nodeInstance);

		// Set the protocol to UDP
		$listenerInstance->setProtocol('udp');

		// Return the prepared instance
		return $listenerInstance;
	}

	/**
	 * Initializes the listener by setting up the required socket server
	 *
	 * @return	void
	 * @throws	InvalidSocketException	Thrown if the socket is invalid or an
	 *									error was detected.
	 */
	public function initListener () {
		// Try to open a UDP socket
		$mainSocket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);

		// Is the socket a valid resource or do we have any error?
		if (!is_resource($mainSocket)) {
			// Then throw an InvalidSocketException
			throw new InvalidSocketException(array($this, gettype($mainSocket), $errno, $errstr), BaseListener::EXCEPTION_INVALID_SOCKET);
		} // END - if

		// Set the option to reuse the port
		$this->debugOutput('LISTENER: Setting re-use address option.');
		if (!socket_set_option($mainSocket, SOL_SOCKET, SO_REUSEADDR, 1)) {
			// Get socket error code for verification
			$socketError = socket_last_error($mainSocket);

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

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

			// And throw again
			throw new InvalidSocketException(array($this, gettype($mainSocket), $socketError, $errorMessage), BaseListener::EXCEPTION_INVALID_SOCKET);
		} // END - if

		// "Bind" the socket to the given address, on given port so this means
		// that all connections on this port are now our resposibility to
		// send/recv data, disconnect, etc..
		$this->debugOutput('LISTENER: Binding to address ' . $this->getListenAddress() . ':' . $this->getListenPort());
		if (!socket_bind($mainSocket, $this->getListenAddress(), $this->getListenPort())) {
			// Get socket error code for verification
			$socketError = socket_last_error($mainSocket);

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

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

			// And throw again
			throw new InvalidSocketException(array($this, gettype($mainSocket), $socketError, $errorMessage), BaseListener::EXCEPTION_INVALID_SOCKET);
		} // END - if

		// Now, we want non-blocking mode
		$this->debugOutput('LISTENER: Setting non-blocking mode.');
		if (!socket_set_nonblock($mainSocket)) {
			// Get socket error code for verification
			$socketError = socket_last_error($socket);

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

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

			// And throw again
			throw new InvalidSocketException(array($this, gettype($mainSocket), $socketError, $errorMessage), BaseListener::EXCEPTION_INVALID_SOCKET);
		} // END - if

		// Remember the socket in our class
		$this->registerServerSocketResource($mainSocket);

		// Output message
		$this->debugOutput('LISTENER: UDP listener now ready on IP ' . $this->getListenAddress() . ', port ' . $this->getListenPort() . ' for service.');
	}

	/**
	 * "Listens" for incoming network packages
	 *
	 * @return	void
	 * @todo	~50% done
	 */
	public function doListen() {
		// Read a package and determine the peer
		$amount = @socket_recvfrom($this->getSocketResource(), $pkt, 1500, 0, $peer, $port);

		// Get last error
		$lastError = socket_last_error($this->getSocketResource());

		// Do we have an error at the line?
		if ($lastError == 11) {
			/*
			 * This (resource temporary unavailable) can be safely ignored on
			 * "listening" UDP ports. If we don't clear the error here, our UDP
			 * "listener" won't read any packages except if the UDP sender
			 * starts the transmission before this "listener came up...
			 */
			socket_clear_error($this->getSocketResource());

			// Skip further processing
			return;
		} elseif ($lastError > 0) {
			// Other error detected
			$this->debugOutput('LISTENER: Error detected: ' . socket_strerror($lastError));

			// Skip further processing
			return;
		} elseif ((empty($pkt)) || (trim($peer) == '')) {
			// Zero sized packages/peer names are usual in non-blocking mode
			return;
		} // END - if

		// Debug only
		$this->debugOutput('LISTENER: Handling UDP package with size ' . strlen($pkt) . ' from peer ' . $peer . ':' . $port);
	}

	/**
	 * Checks wether the listener would accept the given package data array
	 *
	 * @param	$packageData	Raw package data
	 * @return	$accepts		Wether this listener does accept
	 */
	function ifListenerAcceptsPackageData (array $packageData) {
		$this->partialStub('This call should not happen. Please report it.');
	}
}

// [EOF]
?>