/**********************************************************************
** Copyright (C) 2001 Trolltech AS.  All rights reserved.
**
** This file is part of Qtopia Environment.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
** See http://www.trolltech.com/gpl/ for GPL licensing information.
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
**
**********************************************************************/
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <time.h>
#include <locale.h>
#include <math.h>
#include <assert.h>
#include <qapplication.h>

//#define HAVE_MMAP

#if defined(HAVE_MMAP)
#   include <sys/mman.h>
#endif
#include "libmadplugin.h"


extern "C" {
#include "mad.h"
}


#define MPEG_BUFFER_SIZE    65536
//#define debugMsg(a)	    qDebug(a)
#define debugMsg(a)


class Input {
public:
    char const *path;
    int fd;
#if defined(HAVE_MMAP)
    void *fdm;
#endif
    unsigned char *data;
    unsigned long length;
    int eof;
};


class Output {
public:
    mad_fixed_t attenuate;
    struct filter *filters;
    unsigned int channels_in;
    unsigned int channels_out;
    unsigned int speed_in;
    unsigned int speed_out;
    const char *path;
};


# if defined(HAVE_MMAP)
static void *map_file(int fd, unsigned long *length)
{
  void *fdm;

  *length += MAD_BUFFER_GUARD;

  fdm = mmap(0, *length, PROT_READ, MAP_SHARED, fd, 0);
  if (fdm == MAP_FAILED)
    return 0;

# if defined(HAVE_MADVISE)
  madvise(fdm, *length, MADV_SEQUENTIAL);
# endif

  return fdm;
}


static int unmap_file(void *fdm, unsigned long length)
{
  if (munmap(fdm, length) == -1)
    return -1;

  return 0;
}
# endif


static inline QString tr( const char *str ) {
    // Apparently this is okay from a plugin as it runs in the process space of the owner of the plugin
    return qApp->translate( "MediaPlayer", str, "libmad strings for mp3 file info" );
}


class LibMadPluginData {
public:
    Input input;
    Output output;
    int bad_last_frame;
    struct mad_stream stream;
    struct mad_frame frame;
    struct mad_synth synth;
    bool flush;
};


LibMadPlugin::LibMadPlugin() {
    d = new LibMadPluginData;
    d->input.fd = 0;
#if defined(HAVE_MMAP)
    d->input.fdm = 0;
#endif
    d->input.data = 0;
    d->flush = TRUE;
    info = tr( "No Song Open" );
}


LibMadPlugin::~LibMadPlugin() {
    close();
    delete d;
}


bool LibMadPlugin::isFileSupported( const QString& path ) {
    debugMsg( "LibMadPlugin::isFileSupported" );

    // Mpeg file extensions
    //	"mp2","mp3","m1v","m2v","m2s","mpg","vob","mpeg","ac3"
    // Other media extensions
    //  "wav","mid","mod","s3m","ogg","avi","mov","sid"

    char *ext = strrchr( path.latin1(), '.' );

    // Test file extension
    if ( ext ) {
	if ( strncasecmp(ext, ".mp2", 4) == 0 )
	    return TRUE;
	if ( strncasecmp(ext, ".mp3", 4) == 0 )
	    return TRUE;
    }

    return FALSE;
}


bool LibMadPlugin::open( const QString& path ) {
    debugMsg( "LibMadPlugin::open" );

    d->bad_last_frame = 0;
    d->flush = TRUE;
    info = QString( "" );

    //qDebug( "Opening %s", path.latin1() );

    d->input.path = path.latin1();
    d->input.fd = ::open( d->input.path, O_RDONLY );
    if (d->input.fd == -1) {
        qDebug("error opening %s", d->input.path );
	return FALSE;
    }

    printID3Tags();

#if defined(HAVE_MMAP)
    struct stat stat;
    if (fstat(d->input.fd, &stat) == -1) {
	qDebug("error calling fstat"); return FALSE;
    }
    if (S_ISREG(stat.st_mode) && stat.st_size > 0) {
	d->input.length = stat.st_size;
	d->input.fdm = map_file(d->input.fd, &d->input.length);
	if (d->input.fdm == 0) {
	    qDebug("error mmapping file"); return FALSE;
	}
	d->input.data = (unsigned char *)d->input.fdm;
    }
#endif

    if (d->input.data == 0) {
	d->input.data = (unsigned char *)malloc(MPEG_BUFFER_SIZE);
	if (d->input.data == 0) {
	    qDebug("error allocating input buffer");
	    return FALSE;
	}
	d->input.length = 0;
    }

    d->input.eof = 0;

    mad_stream_init(&d->stream);
    mad_frame_init(&d->frame);
    mad_synth_init(&d->synth);

    return TRUE;
}


bool LibMadPlugin::close() {
    debugMsg( "LibMadPlugin::close" );

    int result = TRUE;

    mad_synth_finish(&d->synth);
    mad_frame_finish(&d->frame);
    mad_stream_finish(&d->stream);

#if defined(HAVE_MMAP)
    if (d->input.fdm) {
	if (unmap_file(d->input.fdm, d->input.length) == -1) {
	    qDebug("error munmapping file");
	    result = FALSE;
	}
	d->input.fdm  = 0;
	d->input.data = 0;
    }
#endif

    if (d->input.data) {
        free(d->input.data);
	d->input.data = 0;
    }

    if (::close(d->input.fd) == -1) {
        qDebug("error closing file %s", d->input.path);
	result = FALSE;
    }

    d->input.fd = 0;

    return result;
}


bool LibMadPlugin::isOpen() {
    debugMsg( "LibMadPlugin::isOpen" );
    return ( d->input.fd != 0 );
}


int LibMadPlugin::audioStreams() {
    debugMsg( "LibMadPlugin::audioStreams" );
    return 1;
}


int LibMadPlugin::audioChannels( int ) {
    debugMsg( "LibMadPlugin::audioChannels" );
/*
    long t; short t1[5]; audioReadSamples( t1, 2, 1, t, 0 );
    qDebug( "LibMadPlugin::audioChannels: %i", d->frame.header.mode > 0 ? 2 : 1 );
    return d->frame.header.mode > 0 ? 2 : 1;
*/
    return 2;
}


int LibMadPlugin::audioFrequency( int ) {
    debugMsg( "LibMadPlugin::audioFrequency" );
    long t; short t1[5]; audioReadSamples( t1, 2, 1, t, 0 );
    qDebug( "LibMadPlugin::audioFrequency: %i", d->frame.header.samplerate );
    return d->frame.header.samplerate;
}


int LibMadPlugin::audioSamples( int ) {
    debugMsg( "LibMadPlugin::audioSamples" );
/*
    long t; short t1[5]; audioReadSamples( t1, 2, 1, t, 0 );
    mad_header_decode( (struct mad_header *)&d->frame.header, &d->stream );
    qDebug( "LibMadPlugin::audioSamples: %i*%i", d->frame.header.duration.seconds, d->frame.header.samplerate );
    return d->frame.header.duration.seconds * d->frame.header.samplerate;
*/
    return 10000000;
}


bool LibMadPlugin::audioSetSample( long, int ) {
    debugMsg( "LibMadPlugin::audioSetSample" );
    return FALSE;
}


long LibMadPlugin::audioGetSample( int ) {
    debugMsg( "LibMadPlugin::audioGetSample" );
    return 0;
}

/*
bool LibMadPlugin::audioReadSamples( short *, int, long, int ) {
    debugMsg( "LibMadPlugin::audioReadSamples" );
    return FALSE;
}


bool LibMadPlugin::audioReReadSamples( short *, int, long, int ) {
    debugMsg( "LibMadPlugin::audioReReadSamples" );
    return FALSE;
}
*/

bool LibMadPlugin::read() {
    debugMsg( "LibMadPlugin::read" );
    int len;

      if (d->input.eof)
	return FALSE;

#if defined(HAVE_MMAP)
      if (d->input.fdm) {
	unsigned long skip = 0;

	if (d->stream.next_frame) {
	  struct stat stat;

	  if (fstat(d->input.fd, &stat) == -1)
	    return FALSE;

	  if (stat.st_size + MAD_BUFFER_GUARD <= (signed)d->input.length)
	    return FALSE;

	  // file size changed; update memory map
	  skip = d->stream.next_frame - d->input.data;

	  if (unmap_file(d->input.fdm, d->input.length) == -1) {
	    d->input.fdm  = 0;
	    d->input.data = 0;
	    return FALSE;
	  }

	  d->input.length = stat.st_size;

	  d->input.fdm = map_file(d->input.fd, &d->input.length);
	  if (d->input.fdm == 0) {
	    d->input.data = 0;
	    return FALSE;
	  }

	  d->input.data = (unsigned char *)d->input.fdm;
	}

	mad_stream_buffer(&d->stream, d->input.data + skip, d->input.length - skip);

      } else
#endif
      {
	if (d->stream.next_frame) {
	  memmove(d->input.data, d->stream.next_frame,
		d->input.length = &d->input.data[d->input.length] - d->stream.next_frame);
	}

	do {
	  len = ::read(d->input.fd, d->input.data + d->input.length, MPEG_BUFFER_SIZE - d->input.length);
	}
	while (len == -1 && errno == EINTR);

	if (len == -1) {
	  qDebug("error reading audio");
	  return FALSE;
	}
	else if (len == 0) {
	  d->input.eof = 1;

	  assert(MPEG_BUFFER_SIZE - d->input.length >= MAD_BUFFER_GUARD);

	  while (len < MAD_BUFFER_GUARD)
	    d->input.data[d->input.length + len++] = 0;
	}

	mad_stream_buffer(&d->stream, d->input.data, d->input.length += len);
      }

    return TRUE;
}


static mad_fixed_t left_err, right_err;
static const int bits = 16;
static const int shift = MAD_F_FRACBITS + 1 - bits;


inline long audio_linear_dither( mad_fixed_t sample, mad_fixed_t& error )
{
    sample += error;
    mad_fixed_t quantized = (sample >= MAD_F_ONE) ? MAD_F_ONE - 1 : ( (sample < -MAD_F_ONE) ? -MAD_F_ONE : sample );
    quantized &= ~((1L << shift) - 1);
    error = sample - quantized;
    return quantized >> shift;
}


inline void audio_pcm( short *data, unsigned int nsamples, mad_fixed_t *left, mad_fixed_t *right )
{
    if ( right ) {
	while (nsamples--) {
	    data[0] = audio_linear_dither( *left++,  left_err );
	    data[1] = audio_linear_dither( *right++, right_err );
	    data += 2;
	}
    } else {
	while (nsamples--) {
	    data[0] = data[1] = audio_linear_dither( *left++,  left_err );
	    data += 2;
	}
    }
}


bool LibMadPlugin::decode( short *output, long samples, long& samplesMade ) {
    debugMsg( "LibMadPlugin::decode" );

    static int buffered = 0;
    static mad_fixed_t buffer[2][65536 * 2];
    int offset = buffered;
    samplesMade = 0;

    static int maxBuffered = 8000; // 65536;

    if ( samples > maxBuffered )
	samples = maxBuffered;

    if ( d->flush ) {
	buffered = 0;
	offset = 0;
	d->flush = FALSE;
    }

    while ( buffered < maxBuffered ) {

	while (mad_frame_decode(&d->frame, &d->stream) == -1) {
	    if (!MAD_RECOVERABLE(d->stream.error)) {
		debugMsg( "feed me" );
		return FALSE; // Feed me
	    }
	    if ( d->stream.error == MAD_ERROR_BADCRC ) {
		mad_frame_mute(&d->frame);
		qDebug( "error decoding, bad crc" );
	    }
	}

	mad_synth_frame(&d->synth, &d->frame);
	int decodedSamples = d->synth.pcm.length;
	memcpy( &(buffer[0][offset]), d->synth.pcm.samples[0], decodedSamples * sizeof(mad_fixed_t) );
	if ( d->synth.pcm.channels == 2 )
	    memcpy( &(buffer[1][offset]), d->synth.pcm.samples[1], decodedSamples * sizeof(mad_fixed_t) );
	offset += decodedSamples;
	buffered += decodedSamples;
    }

    audio_pcm( output, samples, buffer[0], (d->synth.pcm.channels == 2) ? buffer[1] : 0 );
//    audio_pcm( output, samples, buffer[1], buffer[0] );
//    audio_pcm( output, samples, buffer[0], buffer[1] );
    samplesMade = samples;
    memmove( buffer[0], &(buffer[0][samples]), (buffered - samples) * sizeof(mad_fixed_t) );
    if ( d->synth.pcm.channels == 2 )
        memmove( buffer[1], &(buffer[1][samples]), (buffered - samples) * sizeof(mad_fixed_t) );
    buffered -= samples;

    return TRUE;
}

/*
bool LibMadPlugin::audioReadMonoSamples( short *, long, long&, int ) {
    debugMsg( "LibMadPlugin::audioReadMonoSamples" );
    return FALSE;
}


bool LibMadPlugin::audioReadStereoSamples( short *output, long samples, long& samplesMade, int ) {
*/
bool LibMadPlugin::audioReadSamples( short *output, int /*channels*/, long samples, long& samplesMade, int ) {
    debugMsg( "LibMadPlugin::audioReadStereoSamples" );

    static bool needInput = TRUE;
    
    if ( samples == 0 )
	return TRUE;

    do {
	if ( needInput )
	    if ( !read() ) {
//		if ( d->input.eof )
//		    needInput = FALSE;
//		else
		    return TRUE;
	    }

	needInput = FALSE;

	if ( decode( output, samples, samplesMade ) )
	    return FALSE;
	else
	    needInput = TRUE;
    }
    while ( ( samplesMade < samples ) && ( !d->input.eof ) );
/*
    static bool firstTimeThru = TRUE;

    if ( firstTimeThru ) {
	firstTimeThru = FALSE;
	decode( output, samples, samplesMade );
	return FALSE;
    } else
*/
        return TRUE;
}


double LibMadPlugin::getTime() {
    debugMsg( "LibMadPlugin::getTime" );
    return 0.0;
}


void LibMadPlugin::printID3Tags() {
    debugMsg( "LibMadPlugin::printID3Tags" );

    char id3v1[128 + 1];

    if ( ::lseek( d->input.fd, -128, SEEK_END ) == -1 ) {
	qDebug( "error seeking to id3 tags" );
	return;
    }

    if ( ::read( d->input.fd, id3v1, 128 ) != 128 ) {
	qDebug( "error reading in id3 tags" );
	return;
    }

    if ( ::strncmp( (const char *)id3v1, "TAG", 3 ) != 0 ) {
	debugMsg( "sorry, no id3 tags" );
    } else {
	int len[5] = { 30, 30, 30, 4, 30 };
	QString label[5] = { tr( "Title" ), tr( "Artist" ), tr( "Album" ), tr( "Year" ), tr( "Comment" ) };
	char *ptr = id3v1 + 3, *ptr2 = ptr + len[0];
	qDebug( "ID3 tags in file:" );
	info = "";
	for ( int i = 0; i < 5; ptr += len[i], i++, ptr2 += len[i] ) {
	    char push = *ptr2;
	    *ptr2 = '\0';
	    char *ptr3 = ptr2;
	    while ( ptr3-1 >= ptr && isspace(ptr3[-1]) ) ptr3--;
	    char push2 = *ptr3; *ptr3 = '\0';
	    if ( strcmp( ptr, "" ) )
		info += ( i != 0 ? ", " : "" ) + label[i] + ": " + ptr;
	    //qDebug( info.latin1() );
	    *ptr3 = push2;
	    *ptr2 = push;
	}
	if (id3v1[126] == 0 && id3v1[127] != 0)
	    info += tr( ", Track: " ) + id3v1[127];
    }

    if ( ::lseek(d->input.fd, 0, SEEK_SET) == -1 ) {
	qDebug( "error seeking back to beginning" );
        return;
    }
}