<?php
// Own namespace
namespace Org\Mxchange\CoreFramework\Stream\Filesystem;

// Import framework stuff
use Org\Mxchange\CoreFramework\EntryPoint\ApplicationEntryPoint;
use Org\Mxchange\CoreFramework\Factory\Object\ObjectFactory;
use Org\Mxchange\CoreFramework\Filesystem\FileNotFoundException;
use Org\Mxchange\CoreFramework\Generic\FrameworkInterface;
use Org\Mxchange\CoreFramework\Generic\UnsupportedOperationException;
use Org\Mxchange\CoreFramework\Middleware\Debug\DebugMiddleware;
use Org\Mxchange\CoreFramework\Object\BaseFrameworkSystem;
use Org\Mxchange\CoreFramework\Stream\Filesystem\FileInputStreamer;
use Org\Mxchange\CoreFramework\Stream\Filesystem\FileOutputStreamer;

// Import SPL stuff
use \InvalidArgumentException;
use \OutOfBoundsException;
use \SplFileInfo;

/**
 * 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 - 2023 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
	 */
	private 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 a FileIoStream class
	 */
	public static final function createFileIoStream () {
		// Create new instance
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage('FILE-IO-STREAM: CALLED!');
		$ioInstance = new FileIoStream();

		// Return the instance
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-IO-STREAM: ioInstance=%s - EXIT!', $ioInstance->__toString()));
		return $ioInstance;
	}

	/**
	 * Saves data to a given local file and create missing directory structures
	 *
	 * @param	$fileInfoInstance	An instance of a SplFileInfo class
	 * @param	$dataArray	The data we shall store to the file
	 * @return	void
	 * @see		FileOutputStreamer
	 * @throws	InvalidArgumentException	If an invalid parameter was given
	 * @throws	OutOfBoundsException	If an expected array element wasn't found
	 */
	public final function saveFile (SplFileInfo $fileInfoInstance, array $dataArray) {
		// Trace message
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-IO-STREAM: fileInfoInstance=%s,dataArray()=%d - CALLED!', $fileInfoInstance, count($dataArray)));
		if (count($dataArray) < 2) {
			// Not valid array, at least 2 elements must be there!
			throw new InvalidArgumentException(sprintf('Parameter "dataArray" should have at least 2 elements, has %d', count($dataArray)));
		} else if (!isset($dataArray[0])) {
			// Array element 0 not found
			throw new OutOfBoundsException(sprintf('Array element dataArray[0] not found, dataArray=%s', json_encode($dataArray)));
		} else if (!isset($dataArray[1])) {
			// Array element 1 not found
			throw new OutOfBoundsException(sprintf('Array element dataArray[1] not found, dataArray=%s', json_encode($dataArray)));
		}

		try {
			// Get a file output pointer
			$fileInstance = ObjectFactory::createObjectByConfiguredName('file_raw_output_class', [$fileInfoInstance, 'wb']);
		} catch (FileNotFoundException $e) {
			// Bail out
			ApplicationEntryPoint::exitApplication('The application has made a fatal error. Exception: ' . $e->__toString() . ' with message: ' . $e->getMessage());
		}

		// Write a header information for validation purposes
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: Writing header to fileInstance=%s ...', $fileInstance->__toString()));
		$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
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: Encoding %d bytes to BASE64 string ...', strlen($dataArray[1])));
		$b64Stream = base64_encode($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
			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: Writing %d bytes to file ...', strlen($line)));
			$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;
		}

		// Close the file
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage('FILE-IO-STREAM: Closing file ...');
		unset($fileInstance);

		// Trace message
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage('FILE-IO-STREAM: EXIT!');
	}

	/**
	 * Reads from a local file
	 *
	 * @param	$infoInstance	An instance of a SplFileInfo class
	 * @return	$array	An array with the element 'header' and 'data'
	 * @see		FileInputStreamer
	 */
	public final function loadFileContents (SplFileInfo $infoInstance) {
		// Initialize some variables and arrays
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-IO-STREAM: infoInstance=%s - CALLED!', $infoInstance));
		$inputBuffer = '';
		$lastBuffer = '';
		$header = [];
		$data = [];
		$readData = ''; // This will contain our read data

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

		// Read all it's contents (we very and transparently decompress it below)
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: fileInstance=%s', $fileInstance->__toString()));
		while ($readRawLine = $fileInstance->readFromFile()) {
			// Add the read line to the buffer
			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: Adding %d read bytes to input buffer.', strlen($readRawLine)));
			$inputBuffer .= $readRawLine;

			// Break infinite loop maybe caused by the input handler
			if ($lastBuffer == $inputBuffer) {
				// Break out of loop, EOF reached?
				/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage('FILE-IO-STREAM: EOF reached!');
				break;
			}

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

		// Close directory handle
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage('FILE-IO-STREAM: Closing file ...');
		unset($fileInstance);

		// Convert it into an array
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: Read inputBuffer=%d bytes from infoInstance=%s', strlen($inputBuffer), $infoInstance));
		$inputArray = explode(chr(10), $inputBuffer);

		// Now process the read lines and verify it's content
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: inputArray()=%d', count($inputArray)));
		foreach ($inputArray as $rawLine) {
			// Trim it a little but not the leading spaces/tab-stops
			$rawLine = rtrim($rawLine);

			// Analyze this line
			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: rawLine()=%d', strlen($rawLine)));
			if (substr($rawLine, 0, 5) == self::FILE_IO_FILE_HEADER_ID) {
				// Header found, so let's extract it
				/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: Found header, rawLine=%s', $rawLine));
				$header = explode(self::FILE_IO_SEPARATOR, $rawLine);
				$headerLine = trim($header[1]);

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

				// Is the header (maybe) valid?
				/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: header()=%d', count($header)));
				if (count($header) != 4) {
					// Throw an exception
					throw new InvalidArrayCountException([$this, 'header', count($header), 4], self::EXCEPTION_ARRAY_HAS_INVALID_COUNT);
				}
			} elseif (substr($rawLine, 0, 5) == self::FILE_IO_DATA_BLOCK_ID) {
				// Is a data line!
				/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: Data line found rawLine=%s', $rawLine));
				$data = explode(self::FILE_IO_SEPARATOR, $rawLine);
				$dataLine = $data[1];

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

				// Validate the read line
				/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: data()=%d', count($data)));
				if (count($data) == 2) {
					// Generate checksum (MD5 is okay here)
					$checksum = md5($data[0]);

					// Check if it matches provided one
					/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: checksum=%s,data[1]=%s', $checksum, $data[1]));
					if ($checksum != $data[1]) {
						// MD5 hash did not match!
						throw new InvalidMD5ChecksumException([$this, $checksum, $data[1]], self::EXCEPTION_MD5_CHECKSUMS_MISMATCH);
					}
				} else {
					// Invalid count!
					throw new InvalidArrayCountException([$this, 'data', count($data), 2], self::EXCEPTION_ARRAY_HAS_INVALID_COUNT);
				}

				// Add this to the readData string
				/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: Adding %d raw data to input stream', strlen($data[0])));
				$readData .= $data[0];
			} else {
				// Other raw lines than header/data tagged lines and re-add the new-line char
				/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: Adding rawLine=%s(%d) + PHP_EOL to input stream', $rawLine, strlen($rawLine)));
				$readData .= $rawLine . PHP_EOL;
			}
		}

		// Was raw lines read and no header/data?
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: readData()=%d,header()=%d,data()=%d', strlen($readData), count($header), count($data)));
		if ((!empty($readData)) && (count($header) == 0) && (count($data) == 0)) {
			// Return raw lines back
			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-IO-STREAM: readData()=%d - EXIT!', strlen($readData)));
			return $readData;
		}

		// Was a header found?
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: header()=%d', count($header)));
		if (count($header) != 4) {
			// Throw an exception
			throw new InvalidArrayCountException([$this, 'header', count($header), 4], self::EXCEPTION_ARRAY_HAS_INVALID_COUNT);
		}

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

		// Does the size match?
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: decodedData()=%d,header[2]=%d', strlen($decodedData), $header[2]));
		if (strlen($decodedData) != $header[2]) {
			// Size did not match
			throw new InvalidDataLengthException([$this, strlen($decodedData), $header[2]], self::EXCEPTION_UNEXPECTED_STRING_SIZE);
		}

		// Generate checksum from whole read data
		$checksum = md5($decodedData);

		// Validate the decoded data with the final MD5 hash
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-IO-STREAM: checksum=%s,header[3]=%s', $checksum, $header[3]));
		if ($checksum != $header[3]) {
			// MD5 hash did not match!
			throw new InvalidMD5ChecksumException([$this, $checksum, $header[3]], self::EXCEPTION_MD5_CHECKSUMS_MISMATCH);
		}

		// Return all in an array
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-IO-STREAM: header()=%d,decodedData()=%d - EXIT!', count($header), strlen($decodedData)));
		return [
			'header' => $header,
			'data'   => $decodedData,
		];
	}

	/**
	 * 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 (string $data) {
		// Not supported
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-IO-STREAM: data=()=%d - CALLED!', strlen($data)));
		throw new UnsupportedOperationException([$this, __FUNCTION__], FrameworkInterface::EXCEPTION_UNSPPORTED_OPERATION);
	}

	/**
	 * Determines seek position
	 *
	 * @return	$seekPosition	Current seek position
	 * @todo	0% done
	 */
	public function determineSeekPosition () {
		// Trace message
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage('FILE-IO-STREAM: CALLED!');
		DebugMiddleware::getSelfInstance()->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 (int $offset, int $whence = SEEK_SET) {
		// Check parameters
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-IO-STREAM: offset=%d,whence=%d - CALLED!', $offset, $whence));
		if ($offset < 0) {
			// Throw IAE
			throw new InvalidArgumentException(sprintf('offset=%d is below zero', $offset), FrameworkInterface::EXCEPTION_INVALID_ARGUMENT);
		} elseif ($whence < 0) {
			// Throw IAE
			throw new InvalidArgumentException(sprintf('whence=%d is below zero', $whence), FrameworkInterface::EXCEPTION_INVALID_ARGUMENT);
		}

		DebugMiddleware::getSelfInstance()->partialStub('offset=' . $offset . ',whence=' . $whence);
	}

	/**
	 * Size of file stack
	 *
	 * @return	$size	Size (in bytes) of file
	 */
	public function size () {
		// Trace message
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage('FILE-IO-STREAM: CALLED!');
		DebugMiddleware::getSelfInstance()->partialStub();
	}

}