<?php
/**
 * A Protocol discovery class
 *
 * @author		Roland Haeder <webmaster@shipsimu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2015 Hub 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 ProtocolDiscovery extends BaseNodeDiscovery implements DiscoverableProtocol, 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 createProtocolDiscovery () {
		// Get an instance of this class
		$discoveryInstance = new ProtocolDiscovery();

		// Return the prepared instance
		return $discoveryInstance;
	}

	/**
	 * Determines the protoctol name
	 *
	 * @param	$packageData		Valid package data
	 * @return	$protocolInstance	An instance of a HandleableProtocol class
	 */
	public static final function determineProtocolByPackageData (array $packageData) {
		// First we need a tags instance
		$tagsInstance = PackageTagsFactory::createPackageTagsInstance();

		/*
		 * We need to decide here which socket (TCP or UDP) should be used for
		 * the actual data transmission. In this process we will find out if
		 * the recipient of this package has already a known (registered) socket
		 * and if so we can re-use it. If there is no socket registered, we try
		 * to make a new connection to the given Universal Node Locator.
		 */
		$protocolInstance = $tagsInstance->chooseProtocolFromPackageData($packageData);

		// Return it
		return $protocolInstance;
	}

	/**
	 * "Discovers" the protocol type from given raw package data. This is done
	 * by looking at the 'recipient' field and extract the first part from it.
	 *
	 * @param	$packageData	Raw package data
	 * @return	$protocolType	Type of protocol, e.g. 'tcp' for TCP/IPv4 connections
	 */
	public static final function discoverProtocolByPackageData (array $packageData) {
		//* DEBUG: */ die(__METHOD__ . ':packageData=' . print_r($packageData, TRUE));

		/*
		 * "Explode" the 'recipient' array element into a new one, giving at
		 * least two entries: protocol://address
		 */
		$recipient = explode(':', $packageData[NetworkPackage::PACKAGE_DATA_RECIPIENT]);

		// At least 2 entries must be found
		assert(count($recipient) >= 2);

		// Now get the first part (protocol type) and make all lower-case
		$protocolType = strtolower($recipient[0]);

		// Return it
		// @TODO Add some validation here???
		return $protocolType;
	}
}

// [EOF]
?>