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

// Import framework stuff
use Org\Mxchange\CoreFramework\Bootstrap\FrameworkBootstrap;
use Org\Mxchange\CoreFramework\Filesystem\BaseFileIo;
use Org\Mxchange\CoreFramework\Filesystem\FileIoException;
use Org\Mxchange\CoreFramework\Filesystem\FileReadProtectedException;
use Org\Mxchange\CoreFramework\Filesystem\FileWriteProtectedException;
use Org\Mxchange\CoreFramework\Filesystem\PathWriteProtectedException;
use Org\Mxchange\CoreFramework\Generic\FrameworkInterface;
use Org\Mxchange\CoreFramework\Generic\NullPointerException;
use Org\Mxchange\CoreFramework\Generic\UnsupportedOperationException;
use Org\Mxchange\CoreFramework\Object\BaseFrameworkSystem;

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

/**
 * A class for reading files
 *
 * @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 FrameworkFileInputOutputPointer extends BaseFileIo implements InputOutputPointer {
	/**
	 * Protected constructor
	 *
	 * @return	void
	 */
	private function __construct () {
		// Call parent constructor
		parent::__construct(__CLASS__);
	}

	/**
	 * Create a file pointer based on the given file. The file will also
	 * be verified here.
	 *
	 * @param	$fileInstance	An instance of a SplFileInfo class
	 * @return	void
	 * @throws	FileReadProtectedException	If PHP cannot read an existing file
	 * @throws	FileWriteProtectedException	If PHP cannot write an existing file
	 * @throws	PathWriteProtectedException	If PHP cannot write to an existing path
	 * @throws	FileIoException				If fopen() returns not a file resource
	 */
	public static final function createFrameworkFileInputOutputPointer (SplFileInfo $fileInstance) {
		// Some pre-sanity checks...
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: fileInstance[%s]=%s - CALLED!', get_class($fileInstance), $fileInstance));
		if (!FrameworkBootstrap::isReachableFilePath($fileInstance)) {
			// File exists but cannot be read
			throw new FileIoException($fileInstance, self::EXCEPTION_FILE_NOT_REACHABLE);
		} elseif ((!FrameworkBootstrap::isReadableFile($fileInstance)) && (file_exists($fileInstance))) {
			// File exists but cannot be read
			throw new FileReadProtectedException($fileInstance, self::EXCEPTION_FILE_CANNOT_BE_READ);
		} elseif (!is_writable($fileInstance->getPath())) {
			// Path is not writable
			throw new PathWriteProtectedException($fileInstance, self::EXCEPTION_PATH_CANNOT_BE_WRITTEN);
		} elseif (($fileInstance->isFile()) && (!$fileInstance->isWritable())) {
			// File exists but cannot be written
			throw new FileWriteProtectedException($fileInstance, self::EXCEPTION_FILE_CANNOT_BE_WRITTEN);
		}

		// Try to open a handler
		$fileObject = $fileInstance->openFile('c+b');

		// Is it valid?
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: fileObject[]=%s', gettype($fileObject)));
		if (!($fileObject instanceof SplFileObject)) {
			// Something bad happend
			throw new FileIoException($fileInstance->getPathname(), self::EXCEPTION_FILE_POINTER_INVALID);
		}

		// Create new instance
		$pointerInstance = new FrameworkFileInputOutputPointer();

		// Set file object and file name
		$pointerInstance->setFileObject($fileObject);

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

	/**
	 * Read 1024 bytes data from a file pointer
	 *
	 * @return	mixed	The result of fread()
	 */
	public function readFromFile () {
		// Read data from the file pointer and return it
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage('FILE-INPUT-OUTPUT-POINTER: CALLED!');
		$data = $this->read(1024);

		// Return data
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: data[%s]=%d - EXIT!', gettype($data), $data));
		return $data;
	}

	/**
	 * Write data to a file pointer
	 *
	 * @param	$dataStream		The data stream we shall write to the file
	 * @return	mixed			Number of writes bytes or false on error
	 */
	public function writeToFile (string $dataStream) {
		// Validate parameter
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: dataStream(%d)=%s - CALLED!', strlen($dataStream), $dataStream));
		if (empty($dataStream)) {
			// Empty dataStream
			throw new InvalidArgumentException('Parameter "dataStream" is empty', FrameworkInterface::EXCEPTION_INVALID_ARGUMENT);
		}

		// Get length
		$length = strlen($dataStream);

		// Write data to the file pointer and return written bytes
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: Invoking this->fileObject->fwrite(%s,%d) ...', $dataStream, $length));
		$status = $this->getFileObject()->fwrite($dataStream, $length);

		// Return status
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: status[%s]=%d - EXIT!', gettype($status), $status));
		return $status;
	}

	/**
	 * Writes at given position by seeking to it.
	 *
	 * @param	$seekPosition	Seek position in file
	 * @param	$dataStream		Data to be written
	 * @return	mixed			Number of writes bytes or false on error
	 * @throws	OutOfBoundsException	If the position is not seekable
	 * @throws	InvalidArgumentException	If a parameter is not valid
	 */
	public function writeAtPosition (int $seekPosition, string $dataStream) {
		// Validate parameter
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: seekPosition=%d,dataStream(%d)=%s - CALLED!', $seekPosition, strlen($dataStream), $dataStream));
		if ($seekPosition < 0) {
			// Invalid seek position
			throw new OutOfBoundsException(sprintf('seekPosition=%d is not valid.', $seekPosition));
		} elseif (empty($dataStream)) {
			// Empty dataStream
			throw new InvalidArgumentException('Parameter "dataStream" is empty', FrameworkInterface::EXCEPTION_INVALID_ARGUMENT);
		} elseif (($this->getFileSize() > 0 || $seekPosition > 0) && $this->seek($seekPosition) === -1) {
			// Could not seek
			throw new InvalidArgumentException(sprintf('Could not seek to seekPosition=%d', $seekPosition));
		}

		// Then write the data at that position
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: Invoking this->writeToFile(%s) ...', $dataStream));
		$status = $this->writeToFile($dataStream);

		// Return status
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: status[%s]=%d - EXIT!', gettype($status), $status));
		return $status;
	}

	/**
	 * Rewinds to the beginning of the file
	 *
	 * @return	void
	 */
	public function rewind () {
		/// Rewind the pointer
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage('FILE-INPUT-OUTPUT-POINTER: CALLED!');
		$this->getFileObject()->rewind();

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

	/**
	 * Seeks to given position
	 *
	 * @param	$seekPosition	Seek position in file
	 * @param	$whence			"Seek mode" (see http://de.php.net/fseek)
	 * @return	$status			Status of this operation
	 * @throws	OutOfBoundsException	If the position is not seekable
	 */
	public function seek (int $seekPosition, int $whence = SEEK_SET) {
		// Validate parameter
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: seekPosition=%d,whence=%d - CALLED!', $seekPosition, $whence));
		if ($seekPosition < 0) {
			// Invalid seek position
			throw new OutOfBoundsException(sprintf('seekPosition=%d is not valid.', $seekPosition));
		} elseif ($whence < 0) {
			// Invalid seek position
			throw new OutOfBoundsException(sprintf('whence=%d is not valid.', $whence));
		}

		// Move the file pointer
		$status = $this->getFileObject()->fseek($seekPosition, $whence);

		// Return status
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: status[%s]=%d - EXIT!', gettype($status), $status));
		return $status;
	}

	/**
	 * Reads a line, maximum 4096 Bytes from current file pointer
	 *
	 * @return	$data	Read data from file
	 */
	public function readLine () {
		// Read whole line
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage('FILE-INPUT-OUTPUT-POINTER: CALLED!');
		$data = $this->read();

		// Return data
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: data[%s]=%s - EXIT!', gettype($data), $data));
		return $data;
	}

	/**
	 * Reads given amount of bytes from file.
	 *
	 * @param	$bytes	Amount of bytes to read
	 * @return	$data	Data read from file
	 * @throws	OutOfBoundsException	If the position is not seekable
	 */
	public function read (int $bytes = 0) {
		// Validatre parameter
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: bytes=%d - CALLED!', $bytes));
		if ($bytes < 0) {
			// Bytes cannot be lesser than zero
			throw new OutOfBoundsException(sprintf('bytes=%d is not valid', $bytes));
		}

		// Is $bytes bigger than zero?
		if ($bytes > 0) {
			// Try to read given characters
			$data = $this->getFileObject()->fread($bytes);
		} else {
			// Try to read whole line
			$data = $this->getFileObject()->fgets();
		}

		// Then return it
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: data[%s]=%s - EXIT!', gettype($data), $data));
		return $data;
	}

	/**
	 * Analyzes entries in index file. This will count all found (and valid)
	 * entries, mark invalid as damaged and count gaps ("fragmentation"). If
	 * only gaps are found, the file is considered as "virgin" (no entries).
	 *
	 * @return	void
	 * @throws	UnsupportedOperationException	If this method is called
	 */
	public function analyzeFileStructure () {
		throw new UnsupportedOperationException([$this, __FUNCTION__], FrameworkInterface::EXCEPTION_UNSPPORTED_OPERATION);
	}

	/**
	 * Advances to next "block" of bytes
	 *
	 * @return	void
	 * @throws	UnsupportedOperationException	If this method is called
	 */
	public function next () {
		throw new UnsupportedOperationException([$this, __FUNCTION__], FrameworkInterface::EXCEPTION_UNSPPORTED_OPERATION);
	}

	/**
	 * Checks wether the current entry is valid (not at the end of the file).
	 * This method will return true if an emptied (nulled) entry has been found.
	 *
	 * @return	$isValid	Whether the next entry is valid
	 * @throws	UnsupportedOperationException	If this method is called
	 */
	public function valid () {
		throw new UnsupportedOperationException([$this, __FUNCTION__], FrameworkInterface::EXCEPTION_UNSPPORTED_OPERATION);
	}

	/**
	 * Gets current seek position ("key").
	 *
	 * @return	$key	Current key in iteration
	 * @throws	UnsupportedOperationException	If this method is called
	 */
	public function key () {
		throw new UnsupportedOperationException([$this, __FUNCTION__], FrameworkInterface::EXCEPTION_UNSPPORTED_OPERATION);
	}

	/**
	 * "Getter" for file size
	 *
	 * @return	$fileSize	Size of currently loaded file
	 * @throws	UnexpectedValueException	If $fileData does not contain "size"
	 */
	public function getFileSize () {
		// Get file's data
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage('FILE-INPUT-OUTPUT-POINTER: CALLED!');
		$fileData = $this->getFileObject()->fstat();

		// Make sure the required array key is there
		if (!isset($fileData['size'])) {
			// Not valid array
			throw new UnexpectedValueException(sprintf('fileData=%s has no element "size"', print_r($fileData, TRUE)), FrameworkInterface::EXCEPTION_UNEXPECTED_VALUE);
		}

		// Return size
		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->traceMessage(sprintf('FILE-INPUT-OUTPUT-POINTER: fileData[size]=%d - EXIT!', $fileData['size']));
		return $fileData['size'];
	}

}