/***************************************************************************
      KwaveMimeData.cpp  -  mime data container for Kwave's audio data
			     -------------------
    begin                : Oct 04 2008
    copyright            : (C) 2008 by Thomas Eschenbacher
    email                : Thomas Eschenbacher <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.                                   *
 *                                                                         *
 ***************************************************************************/

#include "config.h"

#include <limits>
#include <new>

#include <QApplication>
#include <QBuffer>
#include <QMutableListIterator>
#include <QVariant>
#include <QWidget>

#include "libkwave/CodecManager.h"
#include "libkwave/Compression.h"
#include "libkwave/Connect.h"
#include "libkwave/Decoder.h"
#include "libkwave/Encoder.h"
#include "libkwave/MimeData.h"
#include "libkwave/MultiStreamWriter.h"
#include "libkwave/MultiTrackReader.h"
#include "libkwave/MultiTrackWriter.h"
#include "libkwave/Sample.h"
#include "libkwave/SampleReader.h"
#include "libkwave/Signal.h"
#include "libkwave/SignalManager.h"
#include "libkwave/String.h"
#include "libkwave/Utils.h"
#include "libkwave/Writer.h"

#include "libkwave/modules/ChannelMixer.h"
#include "libkwave/modules/RateConverter.h"

// RFC 2361:
#define WAVE_FORMAT_PCM "audio/vnd.wave" // ; codec=001"

/** block size in bytes used as increment when resizing the raw buffer */
#define BUFFER_BLOCK_SIZE (4 * 1024 * 1024) /* 4 MB */

//***************************************************************************
Kwave::MimeData::Buffer::Buffer()
    :QIODevice(), m_block(0), m_size(0), m_data()
{
}

//***************************************************************************
Kwave::MimeData::Buffer::~Buffer()
{
    close();
}

//***************************************************************************
qint64 Kwave::MimeData::Buffer::readData(char *data, qint64 maxlen)
{
    if (atEnd() || (pos() >= size())) return -1;
    if (pos() + maxlen > size())
	maxlen = size() - pos();

    Kwave::MemoryManager &mem = Kwave::MemoryManager::instance();
    return mem.readFrom(
	m_block,
	Kwave::toUint(pos()),
	data,
	Kwave::toUint(maxlen)
    );
}

//***************************************************************************
qint64 Kwave::MimeData::Buffer::writeData(const char *data, qint64 len)
{
    Kwave::MemoryManager &mem = Kwave::MemoryManager::instance();
    quint64 new_size = pos() + len;

    // clip the mime data buffer at the "unsigned int" border
    if (new_size > std::numeric_limits<unsigned int>::max())
	return -1;

    // round up the block size if it can no longer be considered to be a
    // small block (~ half of block size), avoid wasting too much memory
    // if the needed size is very small.
    if (new_size > (BUFFER_BLOCK_SIZE / 2))
	new_size = Kwave::round_up<qint64>(new_size, BUFFER_BLOCK_SIZE);

    if (!m_block) {
	// first call: allocate a new memory object
	m_block = mem.allocate(static_cast<size_t>(new_size));
	if (!m_block) return -1; // allocation failed
    }

    if ((pos() + len) > static_cast<qint64>(mem.sizeOf(m_block))) {
	if (!mem.resize(m_block, static_cast<size_t>(new_size)))
	    return -1; // resize failed
    }

    // write to the memory block (may be physical or swap file)
    qint64 written = mem.writeTo(
	m_block,
	static_cast<unsigned int>(pos()),
	data,
	static_cast<unsigned int>(len)
    );
    if (written < 0)
	return -1; // write failed: disk full?

    if (pos() + written > m_size)
	m_size = pos() + written ; // push the "m_size"

    return written; // write operation was successful
}

//***************************************************************************
bool Kwave::MimeData::Buffer::mapToByteArray()
{
    // reset our QByteArray
    m_data.setRawData(Q_NULLPTR, 0);
    m_data.clear();

    Kwave::MemoryManager &mem = Kwave::MemoryManager::instance();
    const char *raw = (m_block) ?
        static_cast<const char *>(mem.map(m_block)) : Q_NULLPTR;
    if (!raw) {
	// mapping failed: free the block here to avoid trouble
	// in close()
	mem.free(m_block);
	m_block = 0;
	qWarning("Kwave::MimeData::Buffer::mapToByteArray() failed");
	return false; // mmap failed
    }

    // attach the mapped memory to our QByteArray
    const unsigned int len = Kwave::toUint(m_size);
//    qDebug("Kwave::MimeData::Buffer::mapToByteArray() - %p [%u]", raw, len);
    m_data.setRawData(raw, len);
    return true;
}

//***************************************************************************
void Kwave::MimeData::Buffer::close()
{
    QIODevice::close();

    // reset the byte array and it's connection to the block of memory
    m_data.setRawData(Q_NULLPTR, 0);
    m_data.clear();

    // unmap and discard the mapped memory
    if (m_block) {
	Kwave::MemoryManager &mem = Kwave::MemoryManager::instance();
	mem.unmap(m_block);
	mem.free(m_block);
	m_block = 0;
    }
    m_size = 0;
}

//***************************************************************************
//***************************************************************************
Kwave::MimeData::MimeData()
    :QMimeData(), m_buffer()
{
}

//***************************************************************************
Kwave::MimeData::~MimeData()
{
}

//***************************************************************************
bool Kwave::MimeData::encode(QWidget *widget,
                             Kwave::MultiTrackReader &src,
                             const Kwave::MetaDataList &meta_data)
{
    // use our default encoder
    Kwave::Encoder *encoder = Kwave::CodecManager::encoder(_(WAVE_FORMAT_PCM));
    Q_ASSERT(encoder);
    if (!encoder) return false;

    Q_ASSERT(src.tracks());
    if (!src.tracks()) return false;

    // set hourglass cursor
    QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));

    sample_index_t first = src.first();
    sample_index_t last  = src.last();
    Kwave::MetaDataList new_meta_data = meta_data.selectByRange(first, last);

    // move all meta data left, to start at the beginning of the selection
    new_meta_data.shiftLeft(first, first);

    // fix the length information in the new file info
    // and change to uncompressed mode
    Kwave::FileInfo info(meta_data);
    info.set(Kwave::INF_COMPRESSION, QVariant(Kwave::Compression::NONE));
    info.setLength(last - first + 1);
    info.setTracks(src.tracks());
    new_meta_data.replace(Kwave::MetaDataList(info));

    // encode into the buffer
    m_buffer.close(); // discard old stuff
    encoder->encode(widget, src, m_buffer, new_meta_data);

    delete encoder;

    // set the mime data into this mime data container
    bool succeeded = m_buffer.mapToByteArray();
    if (succeeded) {
	// mmap succeeded
	setData(_(WAVE_FORMAT_PCM), m_buffer.byteArray());
    } else {
	// failed to map memory
	m_buffer.close();
    }

    // remove hourglass
    QApplication::restoreOverrideCursor();

    return succeeded;
}

//***************************************************************************
sample_index_t Kwave::MimeData::decode(QWidget *widget, const QMimeData *e,
                                        Kwave::SignalManager &sig,
                                        sample_index_t pos)
{
    // decode, use the first format that matches
    sample_index_t decoded_length = 0;
    unsigned int   decoded_tracks = 0;

    // try to find a suitable decoder
    foreach (const QString &format, e->formats()) {
	// skip all non-supported formats
	if (!Kwave::CodecManager::canDecode(format)) continue;

	Kwave::Decoder *decoder = Kwave::CodecManager::decoder(format);
	Q_ASSERT(decoder);
	if (!decoder) return 0;

	QByteArray raw_data = e->data(format);
	QBuffer src(&raw_data);

	// open the mime source and get header information
	bool ok = decoder->open(widget, src);
	if (!ok) {
	    delete decoder;
	    continue;
	}

	decoded_length = Kwave::FileInfo(decoder->metaData()).length();
	decoded_tracks = Kwave::FileInfo(decoder->metaData()).tracks();
	Q_ASSERT(decoded_length);
	Q_ASSERT(decoded_tracks);
	if (!decoded_length || !decoded_tracks) {
	    delete decoder;
	    continue;
	}

	// get sample rates of source and destination
	double src_rate = Kwave::FileInfo(decoder->metaData()).rate();
	double dst_rate = sig.rate();

	// if the sample rate has to be converted, adjust the length
	// right border
	if (!qFuzzyCompare(src_rate, dst_rate) && (dst_rate > 1) && sig.tracks())
	    decoded_length *= (dst_rate / src_rate);

	sample_index_t left  = pos;
	sample_index_t right = left + decoded_length - 1;
	QList<unsigned int> tracks = sig.selectedTracks();
	if (tracks.isEmpty()) tracks = sig.allTracks();

	// special case: destination is currently empty
	if (!sig.tracks()) {
	    // encode into an empty window -> create tracks
	    qDebug("Kwave::MimeData::decode(...) -> new signal");
	    dst_rate = src_rate;
	    sig.newSignal(0,
		src_rate,
		Kwave::FileInfo(decoder->metaData()).bits(),
		decoded_tracks);
	    ok = (sig.tracks() == decoded_tracks);
	    if (!ok) {
		delete decoder;
		continue;
	    }
	}
	const unsigned int dst_tracks = sig.selectedTracks().count();

	// create the final sink
	Kwave::MultiTrackWriter dst(sig, sig.selectedTracks(),
	                            Kwave::Insert, left, right);

	// if the track count does not match, then we need a channel mixer
	Q_ASSERT(ok);
        Kwave::ChannelMixer *mixer = Q_NULLPTR;
	if (ok && (decoded_tracks != dst_tracks)) {
	    qDebug("Kwave::MimeData::decode(...) -> mixing channels: %u -> %u",
	           decoded_tracks, dst_tracks);
	    mixer = new(std::nothrow)
		Kwave::ChannelMixer(decoded_tracks, dst_tracks);
	    Q_ASSERT(mixer);
	    ok &= (mixer) && mixer->init();
	    Q_ASSERT(ok);
	}
	Q_ASSERT(ok);

	// if the sample rates do not match, then we need a rate converter
        Kwave::StreamObject *rate_converter = Q_NULLPTR;
	if (ok && !qFuzzyCompare(src_rate, dst_rate)) {
	    // create a sample rate converter
	    qDebug("Kwave::MimeData::decode(...) -> rate conversion: "\
	           "%0.1f -> %0.1f", src_rate, dst_rate);
	    rate_converter = new(std::nothrow)
		Kwave::MultiTrackSource<Kwave::RateConverter, true>(
		    dst_tracks, widget);
	    Q_ASSERT(rate_converter);
	    if (rate_converter)
		rate_converter->setAttribute(SLOT(setRatio(QVariant)),
	                                     QVariant(dst_rate / src_rate));
	    else
		ok = false;
	}
	Q_ASSERT(ok);

	// set hourglass cursor
	QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));

	if (ok && (rate_converter || mixer)) {
	    // pass all data through a filter chain
	    Kwave::MultiStreamWriter adapter(decoded_tracks);

	    // pass the data through a sample rate converter
	    // decoder -> adapter -> [mixer] -> [converter] -> dst

	    Kwave::StreamObject *last_output = &adapter;

	    if (ok && mixer) {
		// connect the channel mixer
		ok = Kwave::connect(
		    *last_output, SIGNAL(output(Kwave::SampleArray)),
		    *mixer,       SLOT(input(Kwave::SampleArray))
		);
		last_output = mixer;
	    }

	    if (ok && rate_converter) {
		// connect the rate converter
		ok = Kwave::connect(
		    *last_output,    SIGNAL(output(Kwave::SampleArray)),
		    *rate_converter, SLOT(input(Kwave::SampleArray))
		);
		last_output = rate_converter;
	    }

	    // connect the sink
	    if (ok) {
		ok = Kwave::connect(
		    *last_output, SIGNAL(output(Kwave::SampleArray)),
		    dst,          SLOT(input(Kwave::SampleArray))
		);
	    }

	    // this also starts the conversion automatically
	    if (ok)
		ok = decoder->decode(widget, adapter);

	    // flush all samples that are still in the adapter
	    adapter.flush();

	} else if (ok) {
	    // decode directly without any filter
	    ok = decoder->decode(widget, dst);
	}

	dst.flush();

	// clean up the filter chain
	if (mixer)          delete mixer;
	if (rate_converter) delete rate_converter;

	// remove hourglass
	QApplication::restoreOverrideCursor();

	// failed :-(
	Q_ASSERT(ok);
	if (!ok) {
	    delete decoder;
	    decoded_length = 0;
	    continue;
	}

	// take care of the meta data, shift all it by "left" and
	// add it to the signal
	Kwave::MetaDataList meta_data = decoder->metaData();

        // adjust meta data position in case of different sample rate
        if (!qFuzzyCompare(src_rate, dst_rate))
	    meta_data.scalePositions(dst_rate / src_rate);

	meta_data.shiftRight(0, left);

	// remove the file info, this must not be handled here, otherwise
	// this would overwrite the file info of the destination
	meta_data.remove(meta_data.selectByType(
	    Kwave::FileInfo::metaDataType()));

	// add the remaining meta data (e.g. labels etc)
	sig.metaData().add(meta_data);

	delete decoder;
	break;
    }

//     qDebug("Kwave::MimeData::decode -> decoded_length=%u", decoded_length);
    return decoded_length;
}

//***************************************************************************
void Kwave::MimeData::clear()
{
    m_buffer.close();
}

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