/*************************************************************************
           MP3Encoder.h  -  export of MP3 data via "lame"
                             -------------------
    begin                : Sat May 19 2012
    copyright            : (C) 2012 by Thomas Eschenbacher
    email                : Thomas.Eschenbacher@gmx.de
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   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 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#ifndef MP3_ENCODER_H
#define MP3_ENCODER_H

#include "config.h"

#include <limits.h>

#include <QList>
#include <QMutex>
#include <QProcess>

#include "libkwave/Encoder.h"

#include "ID3_PropertyMap.h"

class ID3_Tag;
class QIODevice;
class QWidget;

namespace Kwave
{

    class MultiTrackReader;

    class MP3Encoder: public Kwave::Encoder
    {
	Q_OBJECT
    public:
	/** Constructor */
	MP3Encoder();

	/** Destructor */
	virtual ~MP3Encoder();

	/** Returns a new instance of the encoder */
	virtual Kwave::Encoder *instance();

	/**
	 * Encodes a signal into a stream of bytes.
	 * @param widget a widget that can be used for displaying
	 *        message boxes or dialogs
	 * @param src MultiTrackReader used as source of the audio data
	 * @param dst file or other source to receive a stream of bytes
	 * @param meta_data meta data of the file to save
	 * @return true if succeeded, false on errors
	 */
	virtual bool encode(QWidget *widget, Kwave::MultiTrackReader &src,
			    QIODevice &dst,
			    const Kwave::MetaDataList &meta_data);

	/** Returns a list of supported file properties */
	virtual QList<Kwave::FileProperty> supportedProperties();

    private slots:

	/** called when data from the external process is available */
	void dataAvailable();

    private:

	/**
	 * encode all meta data into ID3 tags
	 * @param meta_data reference to the meta data to encode
	 * @param tag the ID3 tag to receive the ID3 frames
	 */
	void encodeID3Tags(const Kwave::MetaDataList &meta_data,
	                   ID3_Tag &tag);

    private:

	/** property - to - ID3 mapping */
	ID3_PropertyMap m_property_map;

	/** lock for protecting m_dst and m_process */
	QMutex m_lock;

	/** pointer to the QIODevice for storing, used while encoding */
	QIODevice *m_dst;

	/** the external process with the encoder */
	QProcess m_process;

	/** path to the external program */
	QString m_program;

	/** list with commandline parameters */
	QStringList m_params;

	/**
	 * buffer for writing to the encoder
	 * @note The size of this buffer should never be bigger than
	 * PIPE_BUF (see POSIX.1-2001), otherwise there could be some
	 * leftover when writing to the stdin queue of the process
	 * which would be caught and queued up within Qt.
	 * After some time that leads to a critically increasing memory
	 * consumption and a large delay when the progress bar has
	 * reached 99%.
	 */
	quint8 m_write_buffer[PIPE_BUF];

	/** buffer for reading from the encoder (size is not critical) */
	char m_read_buffer[PIPE_BUF];

    };
}

#endif /* MP3_ENCODER_H */

//***************************************************************************
//***************************************************************************
