/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2023, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */
#pragma once

#include <mrpt/core/optional_ref.h>
#include <mrpt/core/pimpl.h>
#include <mrpt/io/CStream.h>

namespace mrpt::io
{
/** Transparently opens a compressed "gz" file and reads uncompressed data from
 * it.
 * If the file is not a .gz file, it silently reads data from the file.
 *
 * \sa CFileInputStream
 * \ingroup mrpt_io_grp
 */
class CFileGZInputStream : public CStream
{
   private:
	struct Impl;
	mrpt::pimpl<Impl> m_f;
	/** Compressed file size */
	uint64_t m_file_size{0};

   public:
	/** Constructor without open */
	CFileGZInputStream();

	/** Constructor and open
	 * \param fileName The file to be open in this stream
	 * \exception std::exception If there's an error opening the file.
	 */
	CFileGZInputStream(const std::string& fileName);

	CFileGZInputStream(const CFileGZInputStream&) = delete;
	CFileGZInputStream& operator=(const CFileGZInputStream&) = delete;

	/** Dtor */
	~CFileGZInputStream() override;

	std::string getStreamDescription() const override;

	/** Opens the file for read.
	 * \param fileName The file to be open in this stream
	 * \return false if there's an error opening the file, true otherwise
	 */
	bool open(
		const std::string& fileName,
		mrpt::optional_ref<std::string> error_msg = std::nullopt);
	/** Closes the file */
	void close();
	/** Returns true if the file was open without errors. */
	bool fileOpenCorrectly() const;
	/** Returns true if the file was open without errors. */
	bool is_open() { return fileOpenCorrectly(); }
	/** Will be true if EOF has been already reached. */
	bool checkEOF();
	/** Returns the path of the filename passed to open(), or empty if none. */
	std::string filePathAtUse() const;

	/** Method for getting the total number of <b>compressed</b> bytes of in the
	 * file (the physical size of the compressed file). */
	uint64_t getTotalBytesCount() const override;
	/** Method for getting the current cursor position in the <b>compressed</b>,
	 * where 0 is the first byte and TotalBytesCount-1 the last one. */
	uint64_t getPosition() const override;

	/** This method is not implemented in this class */
	uint64_t Seek(int64_t, CStream::TSeekOrigin = sFromBeginning) override;
	size_t Read(void* Buffer, size_t Count) override;
	size_t Write(const void* Buffer, size_t Count) override;
};	// End of class def.
}  // namespace mrpt::io
