<?php
/**
 * An universal class for file input/output streams.
 *
 * @author		Roland Haeder <webmaster@shipsimu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2015 Core 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 FileIoStream extends BaseFrameworkSystem implements FileInputStreamer, FileOutputStreamer {
	/**
	 * File header indicator
	 */
	const FILE_IO_FILE_HEADER_ID = '@head';

	/**
	 * Data block indicator
	 */
	const FILE_IO_DATA_BLOCK_ID = '@data';

	/**
	 * Separator #1
	 */
	const FILE_IO_CHUNKER = ':';

	/**
	 * Separator #2
	 */
	const FILE_IO_SEPARATOR = '^';

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

	/**
	 * Create a file IO stream. This is a class for performing all actions
	 * on files like creating, deleting and loading them.
	 *
	 * @return	$ioInstance	An instance of FileIoStream
	 */
	public static final function createFileIoStream () {
		// Create new instance
		$ioInstance = new FileIoStream();

		// Return the instance
		return $ioInstance;
	}

	/**
	 * Saves data to a given local file and create missing directory structures
	 *
	 * @param	$fileName	The file name for the to be saved file
	 * @param	$dataArray	The data we shall store to the file
	 * @return	void
	 * @see		FileOutputStreamer
	 * @todo	This method needs heavy rewrite
	 */
	public final function saveFile ($fileName, array $dataArray) {
		// Try it five times
		$dirName = '';
		$fileInstance = NULL;

		for ($idx = 0; $idx < 5; $idx++) {
			// Get a file output pointer
			try {
				$fileInstance = ObjectFactory::createObjectByConfiguredName('file_raw_output_class', array($fileName, 'wb'));
			} catch (FileIoException $e) {
				// Bail out
				ApplicationEntryPoint::app_exit('The application has made a fatal error. Exception: ' $e->__toString() . ' with message: ' . $e->getMessage());
			}
		} // END - for

		// Write a header information for validation purposes
		$fileInstance->writeToFile(sprintf('%s%s%s%s%s%s%s%s%s' . PHP_EOL,
			self::FILE_IO_FILE_HEADER_ID,
			self::FILE_IO_SEPARATOR,
			$dataArray[0],
			self::FILE_IO_CHUNKER,
			time(),
			self::FILE_IO_CHUNKER,
			strlen($dataArray[1]),
			self::FILE_IO_CHUNKER,
			md5($dataArray[1])
		));

		// Encode the (maybe) binary stream with Base64
		$b64Stream = base64_encode($dataArray[1]);

		// write the data line by line
		$line = str_repeat(' ', 50); $idx = 0;
		while (strlen($line) == 50) {
			// Get 50 chars or less
			$line = substr($b64Stream, $idx, 50);

			// Save it to the stream
			$fileInstance->writeToFile(sprintf('%s%s%s%s%s' . PHP_EOL,
				self::FILE_IO_DATA_BLOCK_ID,
				self::FILE_IO_SEPARATOR,
				$line,
				self::FILE_IO_CHUNKER,
				md5($line)
			));

			// Advance to the next 50-chars block
			$idx += 50;
		} // END - while

		// Close the file
		unset($fileInstance);
	}

	/**
	 * Reads from a local file
	 *
	 * @param	$fqfn	The full-qualified file-name which we shall load
	 * @return	$array	An array with the element 'header' and 'data'
	 * @see		FileInputStreamer
	 */
	public final function loadFileContents ($fqfn) {
		// Initialize some variables and arrays
		$inputBuffer = '';
		$lastBuffer = '';
		$header = array();
		$data = array();
		$readData = ''; // This will contain our read data

		// Get a file input handler
		$fileInstance = ObjectFactory::createObjectByConfiguredName('file_raw_input_class', array($fqfn));

		// Read all it's contents (we very and transparently decompress it below)
		while ($readRawLine = $fileInstance->readFromFile()) {
			// Add the read line to the buffer
			$inputBuffer .= $readRawLine;

			// Break infinite loop maybe caused by the input handler
			if ($lastBuffer == $inputBuffer) {
				break;
			} // END - if

			// Remember last read line for avoiding possible infinite loops
			$lastBuffer = $inputBuffer;
		} // END - while

		// Close directory handle
		unset($fileInstance);

		// Convert it into an array
		$inputBuffer = explode(chr(10), $inputBuffer);

		// Now process the read lines and verify it's content
		foreach ($inputBuffer as $rawLine) {
			// Trim it a little but not the leading spaces/tab-stops
			$rawLine = rtrim($rawLine);

			// Analyze this line
			if (substr($rawLine, 0, 5) == self::FILE_IO_FILE_HEADER_ID) {
				// Header found, so let's extract it
				$header = explode(self::FILE_IO_SEPARATOR, $rawLine);
				$header = trim($header[1]);

				// Now we must convert it again into an array
				$header = explode(self::FILE_IO_CHUNKER, $header);

				// Is the header (maybe) valid?
				if (count($header) != 4) {
					// Throw an exception
					throw new InvalidArrayCountException(array($this, 'header', count($header), 4), self::EXCEPTION_ARRAY_HAS_INVALID_COUNT);
				} // END - if
			} elseif (substr($rawLine, 0, 5) == self::FILE_IO_DATA_BLOCK_ID) {
				// Is a data line!
				$data = explode(self::FILE_IO_SEPARATOR, $rawLine);
				$data = $data[1];

				// First element is the data, second the MD5 checksum
				$data = explode(self::FILE_IO_CHUNKER, $data);

				// Validate the read line
				if (count($data) == 2) {
					if (md5($data[0]) != $data[1]) {
						// MD5 hash did not match!
						throw new InvalidMD5ChecksumException(array($this, md5($data[0]), $data[1]), self::EXCEPTION_MD5_CHECKSUMS_MISMATCH);
					} // END - if
				} else {
					// Invalid count!
					throw new InvalidArrayCountException(array($this, 'data', count($data), 2), self::EXCEPTION_ARRAY_HAS_INVALID_COUNT);
				}

				// Add this to the readData string
				$readData .= $data[0];
			} else {
				// Other raw lines than header/data tagged lines and re-add the new-line char
				$readData .= $rawLine . PHP_EOL;
			}
		} // END - foreach

		// Was raw lines read and no header/data?
		if ((!empty($readData)) && (count($header) == 0) && (count($data) == 0)) {
			// Return raw lines back
			return $readData;
		} // END - if

		// Was a header found?
		if (count($header) != 4) {
			// Throw an exception
			throw new InvalidArrayCountException(array($this, 'header', count($header), 4), self::EXCEPTION_ARRAY_HAS_INVALID_COUNT);
		} // END - if

		// Decode all from Base64
		$readData = @base64_decode($readData);

		// Does the size match?
		if (strlen($readData) != $header[2]) {
			// Size did not match
			throw new InvalidDataLengthException(array($this, strlen($readData), $header[2]), self::EXCEPTION_UNEXPECTED_STRING_SIZE);
		} // END - if

		// Validate the decoded data with the final MD5 hash
		if (md5($readData) != $header[3]) {
			// MD5 hash did not match!
			throw new InvalidMD5ChecksumException(array($this, md5($readData), $header[3]), self::EXCEPTION_MD5_CHECKSUMS_MISMATCH);
		} // END - if

		// Return all in an array
		return array(
			'header' => $header,
			'data'   => $readData
		);
	}

	/**
	 * Streams the data and maybe does something to it
	 *
	 * @param	$data	The data (string mostly) to "stream"
	 * @return	$data	The data (string mostly) to "stream"
	 * @throws	UnsupportedOperationException	If this method is called
	 */
	public function streamData ($data) {
		self::createDebugInstance(__CLASS__)->debugOutput('Unhandled ' . strlen($data) . ' bytes in this stream.');
		throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
	}

	/**
	 * Determines seek position
	 *
	 * @return	$seekPosition	Current seek position
	 * @todo	0% done
	 */
	public function determineSeekPosition () {
		$this->partialStub();
	}

	/**
	 * Seek to given offset (default) or other possibilities as fseek() gives.
	 *
	 * @param	$offset		Offset to seek to (or used as "base" for other seeks)
	 * @param	$whence		Added to offset (default: only use offset to seek to)
	 * @return	$status		Status of file seek: 0 = success, -1 = failed
	 */
	public function seek ($offset, $whence = SEEK_SET) {
		$this->partialStub('offset=' . $offset . ',whence=' . $whence);
	}

	/**
	 * Size of file stack
	 *
	 * @return	$size	Size (in bytes) of file
	 */
	public function size () {
		$this->partialStub();
	}
}

// [EOF]
?>