<?php
/**
 * A database wrapper for peer state lookups
 *
 * @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 PeerStateLookupDatabaseWrapper extends BaseDatabaseWrapper implements LookupablePeerState {
	// Exception constants
	const EXCEPTION_PEER_ALREADY_REGISTERED = 0x300;

	// Constants for database table names
	const DB_TABLE_PEER_LOOKUP = 'peer_states';

	// Constants for database column names
	const DB_COLUMN_PEER_IP           = 'peer_ip';
	const DB_COLUMN_PEER_PORT         = 'peer_port';
	const DB_COLUMN_PEER_SESSION_ID   = 'peer_session_id';
	const DB_COLUMN_PEER_STATE        = 'peer_state';
	const DB_COLUMN_SOCKET_ERROR_CODE = 'socket_error_code';
	const DB_COLUMN_SOCKET_ERROR_MSG  = 'socket_error_msg';

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

	/**
	 * Creates an instance of this database wrapper by a provided user class
	 *
	 * @return	$wrapperInstance	An instance of the created wrapper class
	 */
	public static final function createPeerStateLookupDatabaseWrapper () {
		// Get a new instance
		$wrapperInstance = new PeerStateLookupDatabaseWrapper();

		// Set (primary!) table name
		$wrapperInstance->setTableName(self::DB_TABLE_PEER_LOOKUP);

		// Return the instance
		return $wrapperInstance;
	}

	/**
	 * "Getter" for a LocalSearchCriteria from given package data's sender
	 *
	 * @param	$packageData		Valid raw package data array
	 * @return	$searchInstance		An instance of a LocalSearchCriteria class
	 */
	private function getSenderSearchInstanceFromPackageData (array $packageData) {
		// Get the instance
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DATABASE-WRAPPER: Searching for sender ' . $packageData[NetworkPackage::PACKAGE_DATA_SENDER]);
		$searchInstance = ObjectFactory::createObjectByConfiguredName('search_criteria_class');

		// Add 'sender' as the peer's IP address
		$searchInstance->addCriteria(self::DB_COLUMN_PEER_SESSION_ID, $packageData[NetworkPackage::PACKAGE_DATA_SENDER]);
		$searchInstance->setLimit(1);

		// Return the instance
		return $searchInstance;
	}

	/**
	 * Checks whether given 'sender' is a new peer
	 *
	 * @param	$packageData		Raw package data
	 * @param	$dataSetInstance	An optional instance of a StoreableCriteria class
	 * @return	$isNewPeer			Whether 'sender' is a new peer to this peer
	 */
	public function isSenderNewPeer (array $packageData, StoreableCriteria $dataSetInstance = NULL) {
		// Debug message
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DATABASE-WRAPPER: ' . __FUNCTION__ . ' called with packageData()=' . count($packageData) . ' - CALLED!');

		// Is the package valid?
		if (!isset($packageData[NetworkPackage::PACKAGE_DATA_SENDER])) {
			// Invalid package found, please report this
			$this->debugBackTrace('[' . __METHOD__ . ':' . __LINE__ . ']:  packageData=' . print_r($packageData, TRUE));
		} // END - if

		// Get a search criteria instance from package data
		$searchInstance = $this->getSenderSearchInstanceFromPackageData($packageData);

		// Is the dataset instance set?
		if ($dataSetInstance instanceof StoreableCriteria) {
			// Then remember the search instance in it
			$dataSetInstance->setSearchInstance($searchInstance);
		} // END - if

		// Count the query
		$entries = $this->doSelectCountByCriteria($searchInstance, array(self::DB_COLUMN_PEER_SESSION_ID => TRUE));

		// Is it there?
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DATABASE-WRAPPER: entries=' . $entries);
		$isNewPeer = ($entries != 1);

		// Return the result
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DATABASE-WRAPPER: isNewPeer=' . intval($isNewPeer) . ' - EXIT!');
		return $isNewPeer;
	}

	/**
	 * Registers a new peer with given package data. We use the session id from it.
	 *
	 * @param	$packageData		Raw package data
	 * @param	$socketResource		A valid socket resource
	 * @return	void
	 * @throws	PeerAlreadyRegisteredException	If a peer is already registered
	 */
	public function registerPeerByPackageData (array $packageData, $socketResource) {
		// Make sure only new peers can be registered with package data
		if (!$this->isSenderNewPeer($packageData)) {
			// Throw an exception because this should normally not happen
			throw new PeerAlreadyRegisteredException(array($this, $packageData), self::EXCEPTION_PEER_ALREADY_REGISTERED);
		} // END - if

		// Generate a dataset instance
		$dataSetInstance = ObjectFactory::createObjectByConfiguredName('dataset_criteria_class', array(self::DB_TABLE_PEER_LOOKUP));

		// Session ids must be unique
		$dataSetInstance->setUniqueKey(self::DB_COLUMN_PEER_SESSION_ID);

		// Add session id
		$dataSetInstance->addCriteria(self::DB_COLUMN_PEER_SESSION_ID, $packageData[NetworkPackage::PACKAGE_DATA_SENDER]);

		// Get peer name
		if (!@socket_getpeername($socketResource, $peerName, $peerPort)) {
			// Get last error
			$lastError = socket_last_error($socketResource);

			// ... and cleartext message from it and put both into criteria
			$dataSetInstance->addCriteria(self::DB_COLUMN_SOCKET_ERROR_CODE, $lastError);
			$dataSetInstance->addCriteria(self::DB_COLUMN_SOCKET_ERROR_MSG , socket_strerror($lastError));
		} // END - if

		// Add ip address and port
		$dataSetInstance->addCriteria(self::DB_COLUMN_PEER_IP  , $peerName);
		$dataSetInstance->addCriteria(self::DB_COLUMN_PEER_PORT, $peerPort);

		// "Insert" the data set
		$this->queryInsertDataSet($dataSetInstance, array(self::DB_COLUMN_PEER_SESSION_ID => TRUE));

		// Debug message
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DATABASE-WRAPPER: Peer ' . $packageData[NetworkPackage::PACKAGE_DATA_SENDER] . ' has been registered.');
	}

	/**
	 * Registers the given peer state and raw package data
	 *
	 * @param	$stateInstance	A PeerStateable class instance
	 * @param	$packageData	Valid package data array
	 * @return	void
	 * @throws	PeerAlreadyRegisteredException	If a peer is already registered
	 * @todo	Unfinished area
	 */
	public function registerPeerState (PeerStateable $stateInstance, array $packageData) {
		// Generate a dataset instance
		$dataSetInstance = ObjectFactory::createObjectByConfiguredName('dataset_criteria_class', array(self::DB_TABLE_PEER_LOOKUP));

		// Session ids must be unique
		$dataSetInstance->setUniqueKey(self::DB_COLUMN_PEER_SESSION_ID);

		// Add session id
		$dataSetInstance->addCriteria(self::DB_COLUMN_PEER_SESSION_ID, $packageData[NetworkPackage::PACKAGE_DATA_SENDER]);
		$dataSetInstance->addCriteria(self::DB_COLUMN_PEER_STATE     , $stateInstance->getStateName());

		// Try to resolve sender's session id
		$senderData = explode(':', HubTools::resolveSessionId($packageData[NetworkPackage::PACKAGE_DATA_SENDER]));

		// Just make sure that 'invalid:invalid' is not being processed
		assert(($senderData[0] != 'invalid') && ($senderData[1] != 'invalid') && ($senderData[2] != 'invalid'));

		// Add ip address and port
		$dataSetInstance->addCriteria(self::DB_COLUMN_PEER_IP  , $senderData[0]);
		$dataSetInstance->addCriteria(self::DB_COLUMN_PEER_PORT, $senderData[1]);

		// Is this a new peer?
		if ($this->isSenderNewPeer($packageData, $dataSetInstance)) {
			// "Insert" the data set
			$this->queryInsertDataSet($dataSetInstance, array(self::DB_COLUMN_PEER_SESSION_ID => TRUE));
		} else {
			// Update the data set
			$this->queryUpdateDataSet($dataSetInstance, array(self::DB_COLUMN_PEER_SESSION_ID => TRUE));
		}

		// Debug message
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DATABASE-WRAPPER: Peer ' . $packageData[NetworkPackage::PACKAGE_DATA_SENDER] . ' has been registered/updated with state ' . $stateInstance->getStateName());
	}

	/**
	 * Purges old entries of given socket resource. We use the IP address from that resource.
	 *
	 * @param	$socketResource		A valid socket resource
	 * @return	void
	 * @throws	InvalidSocketException	If the socket resource was invalid
	 * @todo	Unfinished area
	 */
	public function purgeOldEntriesBySocketResource ($socketResource) {
		// Get peer name
		if (!@socket_getpeername($socketResource, $peerName, $peerPort)) {
			// Get last error
			$lastError = socket_last_error($socketResource);

			// Doesn't work!
			throw new InvalidSocketException(array($this, $socketResource, $lastError, socket_strerror($lastError)), BaseListener::EXCEPTION_INVALID_SOCKET);
		} // END - if

		// Debug message
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DATABASE-WRAPPER: peerName=' . $peerName . ',peerPort=' . $peerPort . ' - UNFINISHED!');
	}

	/**
	 * Checks whether a given peer state (in helper instance) is same as stored
	 * in database compared with the one from $helperInstance.
	 *
	 * @param	$helperInstance			An instance of a ConnectionHelper class
	 * @param	$packageData			Valid package data array
	 * @return	$isSamePeerState		Whether the peer's state is the same
	 */
	public function isSamePeerState (ConnectionHelper $helperInstance, array $packageData) {
		// Debug message
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DATABASE-WRAPPER: State ' . $helperInstance->getPrintableState() . ' needs to be checked it has changed ...');

		// Now get the search instance from given package data
		$searchInstance = $this->getSenderSearchInstanceFromPackageData($packageData);

		// With this search instance query the database for the peer and get a result instance
		$resultInstance = $this->doSelectByCriteria($searchInstance);

		// Do we have an entry? This should always the case
		assert($resultInstance->next());

		// Yes, so get the current (=first) entry from it
		$rowData = $resultInstance->current();

		// Debug message
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DATABASE-WRAPPER: rowData[' . gettype($rowData) . ']=' . print_r($rowData, TRUE));

		// Assert on important elements
		assert(isset($rowData[self::DB_COLUMN_PEER_STATE]));

		// Now just compare it with given state from helper instance
		$isSamePeerState = ($rowData[self::DB_COLUMN_PEER_STATE] == $helperInstance->getPrintableState());

		// Debug message
		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('DATABASE-WRAPPER: state in database: ' . $rowData[self::DB_COLUMN_PEER_STATE] . ', new state: ' . $helperInstance->getPrintableState() . ',isSamePeerState=' . intval($isSamePeerState));

		// Return it
		return $isSamePeerState;
	}
}

// [EOF]
?>