<?php
/**
 * A socket discovery class
 *
 * @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 PackageSocketDiscovery extends BaseHubDiscovery implements DiscoverableSocket, Registerable {
	/**
	 * Protected constructor
	 *
	 * @return	void
	 */
	protected function __construct () {
		// Call parent constructor
		parent::__construct(__CLASS__);
	}

	/**
	 * Create an instance of this class
	 *
	 * @return	$discoveryInstance	An instance of this discovery class
	 */
	public static final function createPackageSocketDiscovery () {
		// Get an instance of this class
		$discoveryInstance = new PackageSocketDiscovery();

		// Output debug message
		$discoveryInstance->debugOutput('SOCKET-DISCOVERY: Initialized.');

		// Return the prepared instance
		return $discoveryInstance;
	}

	/**
	 * Tries to dicover the right listener instance
	 *
	 * @param	$protocolName		Protocol name
	 * @param	$packageData		Raw package data
	 * @return	$listenerInstance	An instance of a Listenable instance or null
	 */
	public function discoverListenerInstance ($protocolName, array $packageData) {
		// Debug message
		//* NOISY-DEBUG: */ $this->debugOutput('SOCKET-DISCOVERY: protocolName=' . $protocolName . ' - ENTERED!');

		/*
		 * Get the listener pool instance, we need to lookup the matching
		 * listener->poolInstance chain there.
		 */
		$poolInstance = Registry::getRegistry()->getInstance('node')->getListenerPoolInstance();

		// Init listener instance
		$listenerInstance = NULL;

		/*
		 * Now we need to choose again. It is whether we are speaking with a hub
		 * or with a client. So just handle it over to all listeners in this
		 * pool.
		 */
		foreach ($poolInstance->getPoolEntriesInstance()->getArrayFromGroup($protocolName) as $listenerInstance) {
			// Debug output
			//* NOISY-DEBUG: */ $this->debugOutput('SOCKET-DISCOVERY: protocolName=' . $protocolName . ',listenerInstance=' . $listenerInstance->__toString());

			// Does the listener want that package?
			if ($listenerInstance->ifListenerAcceptsPackageData($packageData)) {
				// This listener likes our package data, so abort here
				//* NOISY-DEBUG: */ $this->debugOutput('SOCKET-DISCOVERY: Listener is accepting package data.');
				break;
			} // END - if

			// Debug output
			//* NOISY-DEBUG: */ $this->debugOutput('SOCKET-DISCOVERY: Listener is NOT accepting package data.');
		} // END - foreach

		// Return it
		return $listenerInstance;
	}

	/**
	 * Tries to discover the right socket for given package data and returns a
	 * matching socket resource for that protocol.
	 *
	 * @param	$packageData		Raw package data array
	 * @return	$socketResource		A valid socket resource or FALSE if an error occured
	 * @throws	NoListGroupException	If the procol group is not found in peer list
	 * @throws	NullPointerException	If listenerInstance is NULL
	 */
	public function discoverSocket (array $packageData) {
		// Determine protocol name
		$protocolName = $this->determineProtocolByPackageData($packageData);

		// Is it the same?
		assert(strtoupper($protocolName) == $packageData[NetworkPackage::PACKAGE_DATA_PROTOCOL]);

		// Get the listener instance
		$listenerInstance = $this->discoverListenerInstance($protocolName, $packageData);

		// If there is no listener who wants to have that package, we simply drop it here
		if (is_null($listenerInstance)) {
			// Abort with no resource
			throw new NullPointerException($this, self::EXCEPTION_IS_NULL_POINTER);
		} // END - if

		// Debug message
		/* NOISY-DEBUG: */ $this->debugOutput('protocolName=' . $protocolName . ',packageData=' . print_r($packageData, true));

		/*
		 * Now we have the listener instance, we can determine the right
		 * resource to continue. The first step is to get the attached pool
		 * instance and pass over the whole package data to get the right
		 * socket.
		 */
		$socketResource = $listenerInstance->getPoolInstance()->getSocketFromPackageData($packageData);

		// Debug message
		//* NOISY-DEBUG: */ $this->debugOutput('socketResource=' . $socketResource . ',packageData=' . print_r($packageData, true));

		// Is it false, the recipient isn't known to us and we have no connection to it
		if (($socketResource === false) || (!is_resource($socketResource)) || (socket_last_error($socketResource) > 0)) {
			// Try to create a new socket resource
			try {
				// Possibly noisy debug message
				/* NOISY-DEBUG: */ $this->debugOutput('SOCKET-DISCOVERY: Trying to establish a ' . strtoupper($protocolName) . ' connection to ' . $packageData[NetworkPackage::PACKAGE_DATA_RECIPIENT] . ' ...');

				// Get a socket resource from our factory (if succeeded)
				$socketResource = SocketFactory::createSocketFromPackageData($packageData, $protocolName);
			} catch (SocketConnectionException $e) {
				// The connection fails of being established, so log it away
				$this->debugOutput('SOCKET-DISCOVERY: Caught ' . $e->__toString() . ',message=' . $e->getMessage());
			}
		} // END - if

		// Try to resolve the socket resource
		try {
			// Get the helper instance from registry
			$helperInstance = Registry::getRegistry()->getInstance('connection');

			// Possibly noisy debug message
			/* NOISY-DEBUG: */ $this->debugOutput('SOCKET-DISCOVERY: Going to resolve socket from peer state and given package data ...');

			// Resolve the peer's state (but ignore return value)
			PeerStateResolver::resolveStateByPackage($helperInstance, $packageData, $socketResource);
		} catch (InvalidSocketException $e) {
			// This cannot be fixed, so log it away
			$this->debugOutput('SOCKET-DISCOVERY: Cannot discover socket resource for recipient ' . $packageData[NetworkPackage::PACKAGE_DATA_RECIPIENT] . ': ' . $e->getMessage());

			// Make any failed attempts to 'false'
			$socketResource = false;
		}

		// And return it
		//* NOISY-DEBUG: */ $this->debugOutput('SOCKET-DISCOVERY: socketResource=' . $socketResource . ',packageData=' . print_r($packageData, true));
		return $socketResource;
	}
}

// [EOF]
?>