/*****************************************************************************
 * spudec.c : SPU decoder thread
 *****************************************************************************
 * Copyright (C) 2000-2001, 2006 VLC authors and VideoLAN
 *
 * Authors: Sam Hocevar <sam@zoy.org>
 *          Laurent Aimar <fenrir@via.ecp.fr>
 *
 * 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
 *****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

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

#include "spudec.h"

/*****************************************************************************
 * Module descriptor.
 *****************************************************************************/
static int  DecoderOpen   ( vlc_object_t * );
static int  PacketizerOpen( vlc_object_t * );
static void Close         ( vlc_object_t * );

#define DVDSUBTRANS_DISABLE_TEXT N_("Disable DVD subtitle transparency")
#define DVDSUBTRANS_DISABLE_LONGTEXT N_("Removes all transparency effects " \
                                        "used in DVD subtitles.")

vlc_module_begin ()
    set_description( N_("DVD subtitles decoder") )
    set_shortname( N_("DVD subtitles") )
    set_capability( "spu decoder", 75 )
    set_subcategory( SUBCAT_INPUT_SCODEC )
    set_callbacks( DecoderOpen, Close )

    add_bool( "dvdsub-transparency", false,
              DVDSUBTRANS_DISABLE_TEXT, DVDSUBTRANS_DISABLE_LONGTEXT )
    add_submodule ()
    set_description( N_("DVD subtitles packetizer") )
    set_capability( "packetizer", 50 )
    set_callbacks( PacketizerOpen, Close )
vlc_module_end ()

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static block_t *      Reassemble( decoder_t *, block_t * );
static int            Decode    ( decoder_t *, block_t * );
static block_t *      Packetize ( decoder_t *, block_t ** );

static int OpenCommon( vlc_object_t *p_this, bool b_packetizer )
{
    decoder_t     *p_dec = (decoder_t*)p_this;
    decoder_sys_t *p_sys;

    if( p_dec->fmt_in->i_codec != VLC_CODEC_SPU )
        return VLC_EGENERIC;

    p_dec->p_sys = p_sys = malloc( sizeof( decoder_sys_t ) );
    if( !p_sys )
        return VLC_ENOMEM;

    p_sys->b_packetizer = b_packetizer;
    p_sys->b_disabletrans = var_InheritBool( p_dec, "dvdsub-transparency" );
    p_sys->i_spu_size = 0;
    p_sys->i_spu      = 0;
    p_sys->p_block    = NULL;

    if( b_packetizer )
    {
        p_dec->pf_packetize  = Packetize;
        es_format_Copy( &p_dec->fmt_out, p_dec->fmt_in );
        p_dec->fmt_out.i_codec = VLC_CODEC_SPU;
    }
    else
    {
        p_dec->fmt_out.i_codec = VLC_CODEC_SPU;
        p_dec->pf_decode    = Decode;
    }

    return VLC_SUCCESS;
}

static int DecoderOpen( vlc_object_t *p_this )
{
    return OpenCommon( p_this, false );
}

static int PacketizerOpen( vlc_object_t *p_this )
{
    return OpenCommon( p_this, true );
}

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

    if( p_sys->p_block )
    {
        block_ChainRelease( p_sys->p_block );
    }

    free( p_sys );
}

/*****************************************************************************
 * Decode:
 *****************************************************************************/
static int Decode( decoder_t *p_dec, block_t *p_block )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    block_t       *p_spu_block;

    if( p_block == NULL ) /* No Drain */
        return VLCDEC_SUCCESS;
    p_spu_block = Reassemble( p_dec, p_block );

    if( ! p_spu_block )
    {
        return VLCDEC_SUCCESS;
    }

    /* FIXME: what the, we shouldn’t need to allocate 64k of buffer --sam. */
    p_sys->i_spu = block_ChainExtract( p_spu_block, p_sys->buffer, sizeof(p_sys->buffer) );
    p_sys->i_pts = p_spu_block->i_pts;
    block_ChainRelease( p_spu_block );

    /* Parse and decode */
    ParsePacket( p_dec, decoder_QueueSub );

    /* reinit context */
    p_sys->i_spu_size = 0;
    p_sys->i_rle_size = 0;
    p_sys->i_spu      = 0;
    p_sys->p_block    = NULL;

    return VLCDEC_SUCCESS;
}

/*****************************************************************************
 * Packetize:
 *****************************************************************************/
static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    if( pp_block == NULL ) /* No Drain */
        return NULL;
    block_t *p_block = *pp_block; *pp_block = NULL;
    if( p_block == NULL )
        return NULL;

    block_t *p_spu = Reassemble( p_dec, p_block );

    if( ! p_spu )
    {
        return NULL;
    }

    p_spu->i_dts = p_spu->i_pts;
    p_spu->i_length = VLC_TICK_INVALID;

    /* reinit context */
    p_sys->i_spu_size = 0;
    p_sys->i_rle_size = 0;
    p_sys->i_spu      = 0;
    p_sys->p_block    = NULL;

    return block_ChainGather( p_spu );
}

/*****************************************************************************
 * Reassemble:
 *****************************************************************************/
static block_t *Reassemble( decoder_t *p_dec, block_t *p_block )
{
    decoder_sys_t *p_sys = p_dec->p_sys;

    if( p_block->i_flags & BLOCK_FLAG_CORRUPTED )
    {
        block_Release( p_block );
        return NULL;
    }

    if( p_sys->i_spu_size <= 0 &&
        ( p_block->i_pts == VLC_TICK_INVALID || p_block->i_buffer < 4 ) )
    {
        msg_Dbg( p_dec, "invalid starting packet (size < 4 or pts <=0)" );
        msg_Dbg( p_dec, "spu size: %d, i_pts: %"PRId64" i_buffer: %zu",
                 p_sys->i_spu_size, p_block->i_pts, p_block->i_buffer );
        block_Release( p_block );
        return NULL;
    }

    block_ChainAppend( &p_sys->p_block, p_block );
    p_sys->i_spu += p_block->i_buffer;

    if( p_sys->i_spu_size <= 0 )
    {
        p_sys->i_spu_size = ( p_block->p_buffer[0] << 8 )|
            p_block->p_buffer[1];
        p_sys->i_rle_size = ( ( p_block->p_buffer[2] << 8 )|
            p_block->p_buffer[3] ) - 4;

        /* msg_Dbg( p_dec, "i_spu_size=%d i_rle=%d",
                    p_sys->i_spu_size, p_sys->i_rle_size ); */

        if( p_sys->i_spu_size <= 0 || p_sys->i_rle_size >= p_sys->i_spu_size )
        {
            p_sys->i_spu_size = 0;
            p_sys->i_rle_size = 0;
            p_sys->i_spu      = 0;
            p_sys->p_block    = NULL;

            block_Release( p_block );
            return NULL;
        }
    }

    if( p_sys->i_spu >= p_sys->i_spu_size )
    {
        /* We have a complete sub */
        if( p_sys->i_spu > p_sys->i_spu_size )
            msg_Dbg( p_dec, "SPU packets size=%d should be %d",
                     p_sys->i_spu, p_sys->i_spu_size );

        return p_sys->p_block;
    }
    return NULL;
}
