<?php
/**
 * A PackageAssembler class to assemble a package content stream fragemented
 * by PackageFragmenter back to a raw package data array.
 *
 * @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 PackageAssembler extends BaseHubSystem implements Assembler, Registerable {
	/**
	 * Pending data
	 */
	private $pendingData = '';

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

	/**
	 * Creates an instance of this class
	 *
	 * @param	$packageInstance	An instance of a Receivable class
	 * @return	$assemblerInstance	An instance of an Assembler class
	 */
	public static final function createPackageAssembler (Receivable $packageInstance) {
		// Get new instance
		$assemblerInstance = new PackageAssembler();

		// Set package instance here
		$assemblerInstance->setPackageInstance($packageInstance);

		// Return the prepared instance
		return $assemblerInstance;
	}

	/**
	 * Checks whether the input buffer (stacker to be more preceise) is empty.
	 *
	 * @return	$isInputBufferEmpty		Whether the input buffer is empty
	 */
	private function ifInputBufferIsEmpty () {
		// Check it
		$isInputBufferEmpty = $this->getPackageInstance()->getStackerInstance()->isStackEmpty(NetworkPackage::STACKER_NAME_DECODED_HANDLED);

		// Debug message
		//* NOISY-DEBUG: */ $this->debugOutput('PACKAGE-ASSEMBLER: isInputBufferEmpty=' . intval($isInputBufferEmpty));

		// Return it
		return $isInputBufferEmpty;
	}

	/**
	 * Assembles the content from $packageContent. This method does only
	 * initialize the whole process by creating a call-back which will then
	 * itself (99.9% of all cases) "explode" the decoded data stream and add
	 * it to a chunk assembler queue.
	 *
	 * If the call-back method or this would attempt to assemble the package
	 * chunks and (maybe) re-request some chunks from the sender, this would
	 * take to much time and therefore slow down this node again.
	 *
	 * @param	$packageContent		An array with two elements: 'decoded_data' and 'error_code'
	 * @return	void
	 * @throws	UnsupportedPackageCodeHandlerException	If the package code handler is not implemented
	 */
	public function chunkPackageContent (array $packageContent) {
		// Validate the package content array again
		assert(
			(isset($packageContent[BaseRawDataHandler::PACKAGE_DECODED_DATA])) &&
			(isset($packageContent[BaseRawDataHandler::PACKAGE_ERROR_CODE]))
		);

		// Construct call-back name from package error code
		$methodName = 'handlePackageBy' . $this->convertToClassName($packageContent[BaseRawDataHandler::PACKAGE_ERROR_CODE]);

		// Abort if the call-back method is not there
		if (!method_exists($this, $methodName)) {
			// Throw an exception
			throw new UnsupportedPackageCodeHandlerException(array($this, $methodName, $packageContent), BaseListener::EXCEPTION_UNSUPPORTED_PACKAGE_CODE_HANDLER);
		} // END - if

		// Call it back
		call_user_func(array($this, $methodName), $packageContent);
	}

	/**************************************************************************
	 *                 Call-back methods for above method                     *
	 **************************************************************************/

	/**
	 * Call-back handler to handle unhandled packages. This method "explodes"
	 * the string with the chunk separator from PackageFragmenter class, does
	 * some low checks on it and feeds it into another queue for verification
	 * and re-request for bad chunks.
	 *
	 * @param	$packageContent		An array with two elements: 'decoded_data' and 'error_code'
	 * @return	void
	 * @throws	FinalChunkVerificationException		If the final chunk does not start with 'EOP:'
	 */
	private function handlePackageByUnhandledPackage (array $packageContent) {
		// Check for some conditions
		if (!$this->ifInputBufferIsEmpty()) {
			// Last chunk is not valid, so wait for more
			$this->pendingData .= $packageContent[BaseRawDataHandler::PACKAGE_DECODED_DATA];

			// Debug message
			/* NOISY-DEBUG: */ $this->debugOutput('PACKAGE-ASSEMBLER: Partial data received. Waiting for more ... ( ' . strlen($packageContent[BaseRawDataHandler::PACKAGE_DECODED_DATA]) . ' bytes)');
		} else {
			// Debug message
			//* NOISY-DEBUG */ $this->debugOutput('packageContent=' . print_r($packageContent,true) . ',chunks='.print_r($chunks,true));

			/*
			 * "explode" the string from 'decoded_data' with chunk separator to
			 * get an array of chunks. These chunks must then be verified by
			 * their checksums. Also the final chunk must be handled.
			 */
			$chunks = explode(PackageFragmenter::CHUNK_SEPARATOR, $packageContent[BaseRawDataHandler::PACKAGE_DECODED_DATA]);

			// Now get a chunk handler instance
			$handlerInstance = ChunkHandlerFactory::createChunkHandlerInstance();

			// Add all chunks because the last final chunk is found
			$handlerInstance->addAllChunksWithFinal($chunks);
		}
	}

	/**
	 * Checks whether the assembler's pending data is empty which means it has
	 * no pending data left for handling ... ;-)
	 *
	 * @return	$ifPendingDataIsEmpty	Whether pending data is empty
	 */
	public function isPendingDataEmpty () {
		// A simbple check
		$ifPendingDataIsEmpty = empty($this->pendingData);

		// Return it
		return $ifPendingDataIsEmpty;
	}

	/**
	 * Handles the assembler's pending data
	 *
	 * @return	void
	 */
	public function handlePendingData () {
		// Assert on condition
		assert(!$this->isPendingDataEmpty());

		// Init fake array
		$packageContent = array(
			BaseRawDataHandler::PACKAGE_DECODED_DATA => $this->pendingData,
			BaseRawDataHandler::PACKAGE_ERROR_CODE   => BaseRawDataHandler::SOCKET_ERROR_UNHANDLED
		);

		// Clear pending data
		$this->pendingData = '';

		// Debug message
		/* NOISY-DEBUG: */ $this->debugOutput('PACKAGE-ASSEMBLER: Last block of partial data received. A total of ' . strlen($packageContent[BaseRawDataHandler::PACKAGE_DECODED_DATA]) . ' bytes has been received.');

		// Call the real handler method
		$this->handlePackageByUnhandledPackage($packageContent);
	}
}

// [EOF]
?>