/*****************************************************************************
 * flac.c: flac decoder/encoder module making use of libflac
 *****************************************************************************
 * Copyright (C) 1999-2001 VLC authors and VideoLAN
 *
 * Authors: Gildas Bazin <gbazin@videolan.org>
 *          Sigmund Augdal Helberg <dnumgis@videolan.org>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/

/* workaround libflac overriding assert.h system header */
#define assert(x) do {} while(0)

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_codec.h>
#include <vlc_codecs.h>
#include <vlc_aout.h>

#ifdef _WIN32
# define FLAC__NO_DLL
#endif

#include <FLAC/stream_decoder.h>
#include <FLAC/stream_encoder.h>

#include <vlc_block_helper.h>
#include <vlc_bits.h>

#if defined(FLAC_API_VERSION_CURRENT) && FLAC_API_VERSION_CURRENT >= 8
#   define USE_NEW_FLAC_API
#endif

/*****************************************************************************
 * decoder_sys_t : FLAC decoder descriptor
 *****************************************************************************/
typedef struct
{
    /*
     * Input/Output properties
     */
    block_t *p_block;
    block_t *p_aout_buffer;
    date_t   end_date;

    /*
     * FLAC properties
     */
    FLAC__StreamDecoder *p_flac;
    FLAC__StreamMetadata_StreamInfo stream_info;

    uint8_t rgi_channels_reorder[AOUT_CHAN_MAX];
    bool b_stream_info;
} decoder_sys_t;

static const int pi_channels_maps[FLAC__MAX_CHANNELS + 1] =
{
    0,
    AOUT_CHAN_CENTER,
    AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT,
    AOUT_CHAN_CENTER | AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT,
    AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_REARLEFT
     | AOUT_CHAN_REARRIGHT,
    AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
     | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT,
    AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
     | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT | AOUT_CHAN_LFE,
    AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
     | AOUT_CHAN_REARCENTER | AOUT_CHAN_MIDDLELEFT| AOUT_CHAN_MIDDLERIGHT
     | AOUT_CHAN_LFE,
    AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER | AOUT_CHAN_REARLEFT
     | AOUT_CHAN_REARRIGHT | AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT
     | AOUT_CHAN_LFE
};

/* XXX it supposes our internal format is WG4 */
static const uint8_t ppi_reorder[1+FLAC__MAX_CHANNELS][FLAC__MAX_CHANNELS] =
{
    { 0 },
    { 0, },
    { 0, 1 },
    { 0, 1, 2 },
    { 0, 1, 2, 3 },
    { 0, 1, 3, 4, 2 },
    { 0, 1, 4, 5, 2, 3 },
    { 0, 1, 5, 6, 4, 2, 3 },
    { 0, 1, 6, 7, 4, 5, 2, 3 },
};

/* Flac uses same order as waveformatex */
#define MAPPED_WFX_CHANNELS 9
static const uint32_t wfx_remapping[MAPPED_WFX_CHANNELS][2] =
{
    { WAVE_SPEAKER_FRONT_LEFT,              AOUT_CHAN_LEFT },
    { WAVE_SPEAKER_FRONT_RIGHT,             AOUT_CHAN_RIGHT },
    { WAVE_SPEAKER_FRONT_CENTER,            AOUT_CHAN_CENTER },
    { WAVE_SPEAKER_LOW_FREQUENCY,           AOUT_CHAN_LFE },
    { WAVE_SPEAKER_BACK_LEFT,               AOUT_CHAN_REARLEFT },
    { WAVE_SPEAKER_BACK_RIGHT,              AOUT_CHAN_REARRIGHT },
    { WAVE_SPEAKER_BACK_CENTER,             AOUT_CHAN_REARCENTER },
    { WAVE_SPEAKER_SIDE_LEFT,               AOUT_CHAN_MIDDLELEFT },
    { WAVE_SPEAKER_SIDE_RIGHT,              AOUT_CHAN_MIDDLERIGHT },
};

static const uint32_t wfx_chans_order[MAPPED_WFX_CHANNELS + 1] =
{
    AOUT_CHAN_LEFT,
    AOUT_CHAN_RIGHT,
    AOUT_CHAN_CENTER,
    AOUT_CHAN_LFE,
    AOUT_CHAN_REARLEFT,
    AOUT_CHAN_REARRIGHT,
    AOUT_CHAN_REARCENTER,
    AOUT_CHAN_MIDDLELEFT,
    AOUT_CHAN_MIDDLERIGHT,
    0
};

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static int  OpenDecoder   ( vlc_object_t * );
static void CloseDecoder  ( vlc_object_t * );

#ifdef ENABLE_SOUT
static int OpenEncoder   ( vlc_object_t * );
static void CloseEncoder ( encoder_t * );
#endif

static int DecodeBlock( decoder_t *, block_t * );
static void Flush( decoder_t * );

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
vlc_module_begin ()

    set_subcategory( SUBCAT_INPUT_ACODEC )
    add_shortcut( "flac" )

    set_description( N_("Flac audio decoder") )
    set_capability( "audio decoder", 100 )
    set_callbacks( OpenDecoder, CloseDecoder )

#ifdef ENABLE_SOUT
    add_submodule ()
    add_shortcut( "flac" )
    set_description( N_("Flac audio encoder") )
    set_capability( "audio encoder", 100 )
    set_callback( OpenEncoder )
#endif

vlc_module_end ()

/*****************************************************************************
 * Interleave: helper function to interleave channels
 *****************************************************************************/
static void Interleave( int32_t *p_out, const int32_t * const *pp_in,
                        const uint8_t *restrict pi_index, unsigned i_nb_channels,
                        unsigned i_samples, unsigned bits )
{
    unsigned shift = 32 - bits;

    for( unsigned j = 0; j < i_samples; j++ )
        for( unsigned i = 0; i < i_nb_channels; i++ )
        {
            union { int32_t i; uint32_t u; } spl;

            spl.u = ((uint32_t)pp_in[pi_index[i]][j]) << shift;
            p_out[j * i_nb_channels + i] = spl.i;
        }
}

/*****************************************************************************
 * DecoderSetOutputFormat: helper function to convert and check frame format
 *****************************************************************************/
static int DecoderSetOutputFormat( unsigned i_channels, unsigned i_rate,
                                   unsigned i_streaminfo_rate,
                                   unsigned i_bitspersample,
                                   audio_format_t *fmt,
                                   uint8_t *pi_channels_reorder )
{
    if( i_channels == 0 || i_channels > FLAC__MAX_CHANNELS ||
        i_bitspersample == 0 || (i_rate == 0 && i_streaminfo_rate == 0) )
        return VLC_EGENERIC;

    fmt->i_channels = i_channels;
    fmt->i_rate = (i_rate > 0 ) ? i_rate : i_streaminfo_rate;
    fmt->i_physical_channels = pi_channels_maps[i_channels];
    memcpy( pi_channels_reorder, ppi_reorder[i_channels], i_channels );
    fmt->i_bitspersample = i_bitspersample;

    return VLC_SUCCESS;
}

/*****************************************************************************
 * DecoderWriteCallback: called by libflac to output decoded samples
 *****************************************************************************/
static FLAC__StreamDecoderWriteStatus
DecoderWriteCallback( const FLAC__StreamDecoder *decoder,
                      const FLAC__Frame *frame,
                      const FLAC__int32 *const buffer[], void *client_data )
{
    VLC_UNUSED(decoder);
    decoder_t *p_dec = (decoder_t *)client_data;
    decoder_sys_t *p_sys = p_dec->p_sys;

    if( DecoderSetOutputFormat( frame->header.channels,
                                frame->header.sample_rate,
                                p_sys->b_stream_info ? p_sys->stream_info.sample_rate : 0,
                                frame->header.bits_per_sample,
                                &p_dec->fmt_out.audio,
                                p_sys->rgi_channels_reorder ) )
        return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;

    if( p_sys->end_date.i_divider_num != p_dec->fmt_out.audio.i_rate )
    {
        if( p_sys->end_date.i_divider_num > 0 )
            date_Change( &p_sys->end_date, p_dec->fmt_out.audio.i_rate, 1 );
        else
            date_Init( &p_sys->end_date, p_dec->fmt_out.audio.i_rate, 1 );
    }

    if( decoder_UpdateAudioFormat( p_dec ) )
        return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;

    if( date_Get( &p_sys->end_date ) == VLC_TICK_INVALID )
        return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;

    p_sys->p_aout_buffer =
        decoder_NewAudioBuffer( p_dec, frame->header.blocksize );

    if( p_sys->p_aout_buffer == NULL )
        return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;

    Interleave( (int32_t *)p_sys->p_aout_buffer->p_buffer, buffer,
                 p_sys->rgi_channels_reorder,
                 frame->header.channels, frame->header.blocksize,
                 frame->header.bits_per_sample );

    /* Date management (already done by packetizer) */
    p_sys->p_aout_buffer->i_pts = date_Get( &p_sys->end_date );
    p_sys->p_aout_buffer->i_length =
        date_Increment( &p_sys->end_date, frame->header.blocksize ) -
        p_sys->p_aout_buffer->i_pts;

    return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
}

/*****************************************************************************
 * DecoderReadCallback: called by libflac when it needs more data
 *****************************************************************************/
static FLAC__StreamDecoderReadStatus
DecoderReadCallback( const FLAC__StreamDecoder *decoder, FLAC__byte buffer[],
                     size_t *bytes, void *client_data )
{
    VLC_UNUSED(decoder);
    decoder_t *p_dec = (decoder_t *)client_data;
    decoder_sys_t *p_sys = p_dec->p_sys;

    if( p_sys->p_block && p_sys->p_block->i_buffer )
    {
        *bytes = __MIN(*bytes, p_sys->p_block->i_buffer);
        memcpy( buffer, p_sys->p_block->p_buffer, *bytes );
        p_sys->p_block->i_buffer -= *bytes;
        p_sys->p_block->p_buffer += *bytes;
    }
    else
    {
        *bytes = 0;
        return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
    }

    return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
}

/*****************************************************************************
 * DecoderMetadataCallback: called by libflac to when it encounters metadata
 *****************************************************************************/
static void DecoderMetadataCallback( const FLAC__StreamDecoder *decoder,
                                     const FLAC__StreamMetadata *metadata,
                                     void *client_data )
{
    VLC_UNUSED(decoder);
    decoder_t *p_dec = (decoder_t *)client_data;
    decoder_sys_t *p_sys = p_dec->p_sys;

    switch(metadata->type)
    {
        case FLAC__METADATA_TYPE_STREAMINFO:
            /* Setup the format */
            DecoderSetOutputFormat( metadata->data.stream_info.channels,
                                    metadata->data.stream_info.sample_rate,
                                    metadata->data.stream_info.sample_rate,
                                    metadata->data.stream_info.bits_per_sample,
                                    &p_dec->fmt_out.audio, p_sys->rgi_channels_reorder );

            msg_Dbg( p_dec, "channels:%d samplerate:%d bitspersamples:%d",
                     p_dec->fmt_out.audio.i_channels, p_dec->fmt_out.audio.i_rate,
                     p_dec->fmt_out.audio.i_bitspersample );

            p_sys->b_stream_info = true;
            p_sys->stream_info = metadata->data.stream_info;

            date_Init( &p_sys->end_date, p_dec->fmt_out.audio.i_rate, 1 );
            break;

        case FLAC__METADATA_TYPE_VORBIS_COMMENT:
            for( FLAC__uint32 i=0; i<metadata->data.vorbis_comment.num_comments; i++ )
            {
                const FLAC__StreamMetadata_VorbisComment_Entry *comment =
                        &metadata->data.vorbis_comment.comments[i];
                /* Check for custom WAVEFORMATEX channel ordering */
                if( comment->length > 34 &&
                    !strncmp( "WAVEFORMATEXTENSIBLE_CHANNEL_MASK=", (char *) comment->entry, 34 ) )
                {
                    char *endptr = (char *) &comment->entry[34] + comment->length;
                    const uint32_t i_wfxmask = strtoul( (char *) &comment->entry[34], &endptr, 16 );
                    const unsigned i_wfxchannels = vlc_popcount( i_wfxmask );
                    if( i_wfxchannels > 0 && i_wfxchannels <= AOUT_CHAN_MAX )
                    {
                        /* Create the vlc bitmap from wfx channels */
                        uint32_t i_vlcmask = 0;
                        for( uint32_t i_chan = 1; i_chan && i_chan <= i_wfxmask; i_chan <<= 1 )
                        {
                            if( (i_chan & i_wfxmask) == 0 )
                                continue;
                            for( size_t j=0; j<MAPPED_WFX_CHANNELS; j++ )
                            {
                                if( wfx_remapping[j][0] == i_chan )
                                    i_vlcmask |= wfx_remapping[j][1];
                            }
                        }
                        /* Check if we have the 1 to 1 mapping */
                        if( (unsigned) vlc_popcount(i_vlcmask) != i_wfxchannels )
                        {
                            msg_Warn( p_dec, "Unsupported channel mask %x", i_wfxmask );
                            return;
                        }

                        /* Compute the remapping */
                        uint8_t neworder[AOUT_CHAN_MAX] = {0};
                        aout_CheckChannelReorder( wfx_chans_order, NULL,
                                                  i_vlcmask, neworder );

                        /* /!\ Invert our source/dest reordering,
                         * as Interleave() here works source indexes */
                        for( unsigned j=0; j<i_wfxchannels; j++ )
                            p_sys->rgi_channels_reorder[neworder[j]] = j;

                        p_dec->fmt_out.audio.i_physical_channels = i_vlcmask;
                        p_dec->fmt_out.audio.i_channels = i_wfxchannels;
                    }

                    break;
                }
            }

        default:
            break;
    }
}

/*****************************************************************************
 * DecoderErrorCallback: called when the libflac decoder encounters an error
 *****************************************************************************/
static void DecoderErrorCallback( const FLAC__StreamDecoder *decoder,
                                  FLAC__StreamDecoderErrorStatus status,
                                  void *client_data )
{
    VLC_UNUSED(decoder);
    decoder_t *p_dec = (decoder_t *)client_data;
    decoder_sys_t *p_sys = p_dec->p_sys;

    switch( status )
    {
    case FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC:
        msg_Warn( p_dec, "an error in the stream caused the decoder to "
                 "lose synchronization." );
        break;
    case FLAC__STREAM_DECODER_ERROR_STATUS_BAD_HEADER:
        msg_Err( p_dec, "the decoder encountered a corrupted frame header." );
        break;
    case FLAC__STREAM_DECODER_ERROR_STATUS_FRAME_CRC_MISMATCH:
        msg_Err( p_dec, "frame's data did not match the CRC in the "
                 "footer." );
        break;
    case FLAC__STREAM_DECODER_ERROR_STATUS_UNPARSEABLE_STREAM:
        msg_Err( p_dec, "The decoder encountered reserved fields in use in "
                 "the stream." );
        break;
    default:
        msg_Err( p_dec, "got decoder error: %d", status );
    }

    FLAC__stream_decoder_flush( p_sys->p_flac );
    return;
}
/*****************************************************************************
 * OpenDecoder: probe the decoder and return score
 *****************************************************************************/
static int OpenDecoder( vlc_object_t *p_this )
{
    decoder_t *p_dec = (decoder_t*)p_this;
    decoder_sys_t *p_sys;

    if( p_dec->fmt_in->i_codec != VLC_CODEC_FLAC )
    {
        return VLC_EGENERIC;
    }

    /* Allocate the memory needed to store the decoder's structure */
    if( ( p_dec->p_sys = p_sys = malloc(sizeof(*p_sys)) ) == NULL )
        return VLC_ENOMEM;

    /* Misc init */
    p_sys->b_stream_info = false;
    memset(p_sys->rgi_channels_reorder, 0, AOUT_CHAN_MAX);
    p_sys->p_block = NULL;

    /* Take care of flac init */
    if( !(p_sys->p_flac = FLAC__stream_decoder_new()) )
    {
        msg_Err( p_dec, "FLAC__stream_decoder_new() failed" );
        free( p_sys );
        return VLC_EGENERIC;
    }

    /* Enable STREAMINFO + COMMENTS */
    FLAC__stream_decoder_set_metadata_respond( p_sys->p_flac,
                                               FLAC__METADATA_TYPE_VORBIS_COMMENT );

#ifdef USE_NEW_FLAC_API
    if( FLAC__stream_decoder_init_stream( p_sys->p_flac,
                                          DecoderReadCallback,
                                          NULL,
                                          NULL,
                                          NULL,
                                          NULL,
                                          DecoderWriteCallback,
                                          DecoderMetadataCallback,
                                          DecoderErrorCallback,
                                          p_dec )
        != FLAC__STREAM_DECODER_INIT_STATUS_OK )
    {
        msg_Err( p_dec, "FLAC__stream_decoder_init_stream() failed" );
        FLAC__stream_decoder_delete( p_sys->p_flac );
        free( p_sys );
        return VLC_EGENERIC;
    }
#else
    FLAC__stream_decoder_set_read_callback( p_sys->p_flac,
                                            DecoderReadCallback );
    FLAC__stream_decoder_set_write_callback( p_sys->p_flac,
                                             DecoderWriteCallback );
    FLAC__stream_decoder_set_metadata_callback( p_sys->p_flac,
                                                DecoderMetadataCallback );
    FLAC__stream_decoder_set_error_callback( p_sys->p_flac,
                                             DecoderErrorCallback );
    FLAC__stream_decoder_set_client_data( p_sys->p_flac, p_dec );

    FLAC__stream_decoder_init( p_sys->p_flac );
#endif

    /* Set output properties */
    p_dec->fmt_out.i_codec = VLC_CODEC_S32N;

    /* Set callbacks */
    p_dec->pf_decode = DecodeBlock;
    p_dec->pf_flush  = Flush;

    return VLC_SUCCESS;
}

/*****************************************************************************
 * CloseDecoder: flac decoder destruction
 *****************************************************************************/
static void CloseDecoder( vlc_object_t *p_this )
{
    decoder_t *p_dec = (decoder_t *)p_this;
    decoder_sys_t *p_sys = p_dec->p_sys;

    FLAC__stream_decoder_finish( p_sys->p_flac );
    FLAC__stream_decoder_delete( p_sys->p_flac );

    if( p_sys->p_block )
        block_Release( p_sys->p_block );
    free( p_sys );
}

/*****************************************************************************
 * ProcessHeader: process Flac header.
 *****************************************************************************/
static void ProcessHeader( decoder_t *p_dec )
{
    decoder_sys_t *p_sys = p_dec->p_sys;

    if( !p_dec->fmt_in->i_extra )
        return;

    /* Decode STREAMINFO */
    msg_Dbg( p_dec, "decode STREAMINFO" );
    int i_extra = p_dec->fmt_in->i_extra;

    static const char header[4] = { 'f', 'L', 'a', 'C' };

    if( memcmp( p_dec->fmt_in->p_extra, header, 4 ) )
        i_extra += 8;

    p_sys->p_block = block_Alloc( i_extra );
    if( p_sys->p_block == NULL )
        return;

    uint8_t *p_data = p_sys->p_block->p_buffer;
    if( i_extra != p_dec->fmt_in->i_extra )
    {
        memcpy( p_data, header, 4);
        p_data[4] = 0x80 | 0; /* STREAMINFO faked as last block */
        p_data[5] = 0;
        p_data[6] = 0;
        p_data[7] = 34; /* block size */
        p_data += 8;
    }
    memcpy( p_data, p_dec->fmt_in->p_extra, p_dec->fmt_in->i_extra );

    FLAC__stream_decoder_process_until_end_of_metadata( p_sys->p_flac );
    msg_Dbg( p_dec, "STREAMINFO decoded" );

    block_Release( p_sys->p_block );
    p_sys->p_block = NULL;
}

/*****************************************************************************
 * decoder_state_error: print meaningful error messages
 *****************************************************************************/
static void decoder_state_error( decoder_t *p_dec,
                                 FLAC__StreamDecoderState state )
{
    switch ( state )
    {
    case FLAC__STREAM_DECODER_SEARCH_FOR_METADATA:
        msg_Dbg( p_dec, "the decoder is ready to search for metadata." );
        break;
    case FLAC__STREAM_DECODER_READ_METADATA:
        msg_Dbg( p_dec, "the decoder is ready to or is in the process of "
                 "reading metadata." );
        break;
    case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
        msg_Dbg( p_dec, "the decoder is ready to or is in the process of "
                 "searching for the frame sync code." );
        break;
    case FLAC__STREAM_DECODER_READ_FRAME:
        msg_Dbg( p_dec, "the decoder is ready to or is in the process of "
                 "reading a frame." );
        break;
    case FLAC__STREAM_DECODER_END_OF_STREAM:
        msg_Dbg( p_dec, "the decoder has reached the end of the stream." );
        break;
#ifdef USE_NEW_FLAC_API
    case FLAC__STREAM_DECODER_OGG_ERROR:
        msg_Err( p_dec, "error occurred in the Ogg layer." );
        break;
    case FLAC__STREAM_DECODER_SEEK_ERROR:
        msg_Err( p_dec, "error occurred while seeking." );
        break;
#endif
    case FLAC__STREAM_DECODER_ABORTED:
        msg_Warn( p_dec, "the decoder was aborted by the read callback." );
        break;
#ifndef USE_NEW_FLAC_API
    case FLAC__STREAM_DECODER_UNPARSEABLE_STREAM:
        msg_Warn( p_dec, "the decoder encountered reserved fields in use "
                 "in the stream." );
        break;
#endif
    case FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR:
        msg_Err( p_dec, "error when allocating memory." );
        break;
#ifndef USE_NEW_FLAC_API
    case FLAC__STREAM_DECODER_ALREADY_INITIALIZED:
        msg_Err( p_dec, "FLAC__stream_decoder_init() was called when the "
                 "decoder was already initialized, usually because "
                 "FLAC__stream_decoder_finish() was not called." );
        break;
    case FLAC__STREAM_DECODER_INVALID_CALLBACK:
        msg_Err( p_dec, "FLAC__stream_decoder_init() was called without "
                 "all callbacks being set." );
        break;
#endif
    case FLAC__STREAM_DECODER_UNINITIALIZED:
        msg_Err( p_dec, "decoder in uninitialized state." );
        break;
    default:
        msg_Warn(p_dec, "unknown error" );
    }
}

/*****************************************************************************
 * Flush:
 *****************************************************************************/
static void Flush( decoder_t *p_dec )
{
    decoder_sys_t *p_sys = p_dec->p_sys;

    if( p_sys->b_stream_info )
        FLAC__stream_decoder_flush( p_sys->p_flac );
    date_Set( &p_sys->end_date, VLC_TICK_INVALID );
}

/****************************************************************************
 * DecodeBlock: the whole thing
 ****************************************************************************/
static int DecodeBlock( decoder_t *p_dec, block_t *p_block )
{
    decoder_sys_t *p_sys = p_dec->p_sys;

    if( p_block == NULL ) /* No Drain */
        return VLCDEC_SUCCESS;
    if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY | BLOCK_FLAG_CORRUPTED) )
    {
        Flush( p_dec );
        if( p_block->i_flags & BLOCK_FLAG_CORRUPTED )
        {
            block_Release( p_block );
            return VLCDEC_SUCCESS;
        }
    }

    if( !p_sys->b_stream_info )
    {
        ProcessHeader( p_dec );
        if( !p_sys->b_stream_info )
        {
            block_Release( p_block );
            return VLCDEC_ECRITICAL;
        }
    }

    p_sys->p_block = p_block;

    if( p_sys->p_block->i_pts != VLC_TICK_INVALID &&
        p_sys->p_block->i_pts != date_Get( &p_sys->end_date ) )
        date_Set( &p_sys->end_date, p_sys->p_block->i_pts );

    p_sys->p_aout_buffer = 0;

    if( !FLAC__stream_decoder_process_single( p_sys->p_flac ) )
    {
        decoder_state_error( p_dec,
                             FLAC__stream_decoder_get_state( p_sys->p_flac ) );
        FLAC__stream_decoder_flush( p_sys->p_flac );
    }

    /* If the decoder is in the "aborted" state,
     * FLAC__stream_decoder_process_single() won't return an error. */
    switch ( FLAC__stream_decoder_get_state(p_sys->p_flac) )
    {
        case FLAC__STREAM_DECODER_ABORTED:
            FLAC__stream_decoder_flush( p_sys->p_flac );
            break;
        case FLAC__STREAM_DECODER_END_OF_STREAM:
            FLAC__stream_decoder_reset( p_sys->p_flac );
            break;
        default:
            break;
    }

    block_Release( p_sys->p_block );
    p_sys->p_block = NULL;

    if( p_sys->p_aout_buffer != NULL )
        decoder_QueueAudio( p_dec, p_sys->p_aout_buffer );
    return VLCDEC_SUCCESS;
}

#ifdef ENABLE_SOUT

/*****************************************************************************
 * encoder_sys_t : flac encoder descriptor
 *****************************************************************************/
typedef struct
{
    /*
     * Input properties
     */
    int i_headers;

    int i_samples_delay;

    FLAC__int32 *p_buffer;
    unsigned int i_buffer;

    block_t *p_chain;

    /*
     * FLAC properties
     */
    FLAC__StreamEncoder *p_flac;
    FLAC__StreamMetadata_StreamInfo stream_info;

    /*
     * Common properties
     */
    vlc_tick_t i_pts;
} encoder_sys_t;

#define STREAMINFO_SIZE 34

static block_t *Encode( encoder_t *, block_t * );

/*****************************************************************************
 * EncoderWriteCallback: called by libflac to output encoded samples
 *****************************************************************************/
static FLAC__StreamEncoderWriteStatus
EncoderWriteCallback( const FLAC__StreamEncoder *encoder,
                      const FLAC__byte buffer[],
                      size_t bytes, unsigned samples,
                      unsigned current_frame, void *client_data )
{
    VLC_UNUSED(encoder); VLC_UNUSED(current_frame);
    encoder_t *p_enc = (encoder_t *)client_data;
    encoder_sys_t *p_sys = p_enc->p_sys;
    block_t *p_block;

    if( samples == 0 )
    {
        if( p_sys->i_headers == 1 )
        {
            msg_Dbg( p_enc, "Writing STREAMINFO: %zu", bytes );

            /* Backup the STREAMINFO metadata block */
            p_enc->fmt_out.i_extra = STREAMINFO_SIZE + 8;
            p_enc->fmt_out.p_extra = xmalloc( STREAMINFO_SIZE + 8);
            memcpy(p_enc->fmt_out.p_extra, "fLaC", 4);
            memcpy((uint8_t*)p_enc->fmt_out.p_extra + 4, buffer, STREAMINFO_SIZE );
            /* Fake this as the last metadata block */
            ((uint8_t*)p_enc->fmt_out.p_extra)[4] |= 0x80;
        }
        p_sys->i_headers++;
        return FLAC__STREAM_ENCODER_WRITE_STATUS_OK;
    }

    p_block = block_Alloc( bytes );
    memcpy( p_block->p_buffer, buffer, bytes );

    p_block->i_dts = p_block->i_pts = p_sys->i_pts;

    p_sys->i_samples_delay -= samples;

    p_block->i_length = vlc_tick_from_samples(samples, p_enc->fmt_in.audio.i_rate);

    /* Update pts */
    p_sys->i_pts += p_block->i_length;

    block_ChainAppend( &p_sys->p_chain, p_block );

    return FLAC__STREAM_ENCODER_WRITE_STATUS_OK;
}
/*****************************************************************************
 * EncoderMetadataCallback: called by libflac to output metadata
 *****************************************************************************/
static void EncoderMetadataCallback( const FLAC__StreamEncoder *encoder,
                                     const FLAC__StreamMetadata *metadata,
                                     void *client_data )
{
    VLC_UNUSED(encoder);
    encoder_t *p_enc = (encoder_t *)client_data;

    msg_Err( p_enc, "MetadataCallback: %i", metadata->type );
    return;
}

/*****************************************************************************
 * OpenEncoder: probe the encoder and return score
 *****************************************************************************/
static int OpenEncoder( vlc_object_t *p_this )
{
    encoder_t *p_enc = (encoder_t *)p_this;
    encoder_sys_t *p_sys;

    if( p_enc->fmt_out.i_codec != VLC_CODEC_FLAC &&
        !p_enc->obj.force )
    {
        return VLC_EGENERIC;
    }

    /* Allocate the memory needed to store the decoder's structure */
    if( ( p_sys = (encoder_sys_t *)malloc(sizeof(encoder_sys_t)) ) == NULL )
        return VLC_ENOMEM;
    p_enc->p_sys = p_sys;
    p_enc->fmt_out.i_codec = VLC_CODEC_FLAC;

    p_sys->i_headers = 0;
    p_sys->p_buffer = 0;
    p_sys->i_buffer = 0;
    p_sys->i_samples_delay = 0;

    /* Create flac encoder */
    if( !(p_sys->p_flac = FLAC__stream_encoder_new()) )
    {
        msg_Err( p_enc, "FLAC__stream_encoder_new() failed" );
        free( p_sys );
        return VLC_EGENERIC;
    }

    FLAC__stream_encoder_set_streamable_subset( p_sys->p_flac, 1 );
    FLAC__stream_encoder_set_channels( p_sys->p_flac,
                                       p_enc->fmt_in.audio.i_channels );
    FLAC__stream_encoder_set_sample_rate( p_sys->p_flac,
                                          p_enc->fmt_in.audio.i_rate );
    FLAC__stream_encoder_set_bits_per_sample( p_sys->p_flac, 16 );
    p_enc->fmt_in.i_codec = VLC_CODEC_S16N;

    /* Get and store the STREAMINFO metadata block as a p_extra */
    p_sys->p_chain = 0;

#ifdef USE_NEW_FLAC_API
    if( FLAC__stream_encoder_init_stream( p_sys->p_flac,
                                          EncoderWriteCallback,
                                          NULL,
                                          NULL,
                                          EncoderMetadataCallback,
                                          p_enc )
        != FLAC__STREAM_ENCODER_INIT_STATUS_OK )
    {
        msg_Err( p_enc, "FLAC__stream_encoder_init_stream() failed" );
        FLAC__stream_encoder_delete( p_sys->p_flac );
        free( p_sys );
        return VLC_EGENERIC;
    }
#else
    FLAC__stream_encoder_set_write_callback( p_sys->p_flac,
        EncoderWriteCallback );
    FLAC__stream_encoder_set_metadata_callback( p_sys->p_flac,
        EncoderMetadataCallback );
    FLAC__stream_encoder_set_client_data( p_sys->p_flac, p_enc );

    FLAC__stream_encoder_init( p_sys->p_flac );
#endif

    static const struct vlc_encoder_operations ops =
    {
        .close = CloseEncoder,
        .encode_audio = Encode,
    };
    p_enc->ops = &ops;

    return VLC_SUCCESS;
}

/****************************************************************************
 * Encode: the whole thing
 ****************************************************************************
 * This function spits out ogg packets.
 ****************************************************************************/
static block_t *Encode( encoder_t *p_enc, block_t *p_aout_buf )
{
    encoder_sys_t *p_sys = p_enc->p_sys;
    block_t *p_chain;

    /* FIXME: p_aout_buf is NULL when it's time to flush*/
    if( unlikely( !p_aout_buf ) ) return NULL;

    p_sys->i_pts = p_aout_buf->i_pts -
                vlc_tick_from_samples( p_sys->i_samples_delay,
                            p_enc->fmt_in.audio.i_rate );

    p_sys->i_samples_delay += p_aout_buf->i_nb_samples;

    /* Convert samples to FLAC__int32 */
    if( p_sys->i_buffer < p_aout_buf->i_buffer * sizeof(FLAC__int32) )
    {
        p_sys->p_buffer =
            xrealloc( p_sys->p_buffer, p_aout_buf->i_buffer * sizeof(FLAC__int32) );
        p_sys->i_buffer = p_aout_buf->i_buffer * 2;
    }

    for( unsigned i = 0 ; i < p_aout_buf->i_buffer / 2 ; i++ )
    {
        p_sys->p_buffer[i]= ((int16_t *)p_aout_buf->p_buffer)[i];
    }

    FLAC__stream_encoder_process_interleaved( p_sys->p_flac, p_sys->p_buffer,
                                              p_aout_buf->i_nb_samples );

    p_chain = p_sys->p_chain;
    p_sys->p_chain = 0;

    return p_chain;
}

/*****************************************************************************
 * CloseEncoder: encoder destruction
 *****************************************************************************/
static void CloseEncoder( encoder_t *p_enc )
{
    encoder_sys_t *p_sys = p_enc->p_sys;

    FLAC__stream_encoder_delete( p_sys->p_flac );

    free( p_sys->p_buffer );
    free( p_sys );
}
#endif
