/* $Id: reader.c,v 1.21 2005/11/25 15:05:25 titer Exp $

   This file is part of the HandBrake source code.
   Homepage: <http://handbrake.fr/>.
   It may be used under the terms of the GNU General Public License. */

#include "hb.h"

typedef struct
{
    double average; // average time between packets
    int64_t last;   // last timestamp seen on this stream
    int id;         // stream id
    int is_audio;   // != 0 if this is an audio stream
} stream_timing_t;

typedef struct
{
    hb_job_t     * job;
    hb_title_t   * title;
    volatile int * die;

    hb_dvd_t     * dvd;
    hb_stream_t  * stream;

    stream_timing_t *stream_timing;
    int64_t        scr_offset;
    hb_psdemux_t   demux;
    int            scr_changes;
    uint32_t       sequence;
    uint8_t        st_slots;        // size (in slots) of stream_timing array
    uint8_t        saw_video;       // != 0 if we've seen video
    uint8_t        saw_audio;       // != 0 if we've seen audio
} hb_reader_t;

/***********************************************************************
 * Local prototypes
 **********************************************************************/
static void        ReaderFunc( void * );
static hb_fifo_t ** GetFifoForId( hb_job_t * job, int id );

/***********************************************************************
 * hb_reader_init
 ***********************************************************************
 *
 **********************************************************************/
hb_thread_t * hb_reader_init( hb_job_t * job )
{
    hb_reader_t * r;

    r = calloc( sizeof( hb_reader_t ), 1 );

    r->job   = job;
    r->title = job->title;
    r->die   = job->die;
    r->sequence = 0;

    r->st_slots = 4;
    r->stream_timing = calloc( sizeof(stream_timing_t), r->st_slots );
    r->stream_timing[0].id = r->title->video_id;
    r->stream_timing[0].average = 90000. * (double)job->vrate_base /
                                           (double)job->vrate;
    r->stream_timing[0].last = -r->stream_timing[0].average;
    r->stream_timing[1].id = -1;

    return hb_thread_init( "reader", ReaderFunc, r,
                           HB_NORMAL_PRIORITY );
}

static void push_buf( const hb_reader_t *r, hb_fifo_t *fifo, hb_buffer_t *buf )
{
    while( !*r->die && !r->job->done && hb_fifo_is_full( fifo ) )
    {
        /*
         * Loop until the incoming fifo is ready to receive
         * this buffer.
         */
        hb_snooze( 50 );
    }
    hb_fifo_push( fifo, buf );
}

static int is_audio( hb_reader_t *r, int id )
{
    int i;
    hb_audio_t *audio;

    for( i = 0; ( audio = hb_list_item( r->title->list_audio, i ) ); ++i )
    {
        if ( audio->id == id )
        {
            return 1;
        }
    }
    return 0;
}

// The MPEG STD (Standard Target Decoder) essentially requires that we keep
// per-stream timing so that when there's a timing discontinuity we can
// seemlessly join packets on either side of the discontinuity. This join
// requires that we know the timestamp of the previous packet and the
// average inter-packet time (since we position the new packet at the end
// of the previous packet). The next four routines keep track of this
// per-stream timing.

// find the per-stream timing state for 'buf'

static stream_timing_t *find_st( hb_reader_t *r, const hb_buffer_t *buf )
{
    stream_timing_t *st = r->stream_timing;
    for ( ; st->id != -1; ++st )
    {
        if ( st->id == buf->id )
            return st;
    }
    return NULL;
}

// find or create the per-stream timing state for 'buf'

static stream_timing_t *id_to_st( hb_reader_t *r, const hb_buffer_t *buf )
{
    stream_timing_t *st = r->stream_timing;
    while ( st->id != buf->id && st->id != -1)
    {
        ++st;
    }
    // if we haven't seen this stream add it.
    if ( st->id == -1 )
    {
        // we keep the steam timing info in an array with some power-of-two
        // number of slots. If we don't have two slots left (one for our new
        // entry plus one for the "-1" eol) we need to expand the array.
        int slot = st - r->stream_timing;
        if ( slot + 1 >= r->st_slots )
        {
            r->st_slots *= 2;
            r->stream_timing = realloc( r->stream_timing, r->st_slots *
                                        sizeof(*r->stream_timing) );
            st = r->stream_timing + slot;
        }
        st->id = buf->id;
        st->average = 30.*90.;
        if ( r->saw_video )
            st->last = buf->renderOffset - st->average;
        else
            st->last = -st->average;
        if ( ( st->is_audio = is_audio( r, buf->id ) ) != 0 )
        {
            r->saw_audio = 1;
        }
        st[1].id = -1;
    }
    return st;
}

// update the average inter-packet time of the stream associated with 'buf'
// using a recursive low-pass filter with a 16 packet time constant.

static void update_ipt( hb_reader_t *r, const hb_buffer_t *buf )
{
    stream_timing_t *st = id_to_st( r, buf );
    double dt = buf->renderOffset - st->last;
    st->average += ( dt - st->average ) * (1./32.);
    st->last = buf->renderOffset;
}

// use the per-stream state associated with 'buf' to compute a new scr_offset
// such that 'buf' will follow the previous packet of this stream separated
// by the average packet time of the stream.

static void new_scr_offset( hb_reader_t *r, hb_buffer_t *buf )
{
    stream_timing_t *st = id_to_st( r, buf );
    int64_t nxt = st->last + st->average;
    r->scr_offset = buf->renderOffset - nxt;
    buf->renderOffset = nxt;
    r->scr_changes = r->demux.scr_changes;
    st->last = buf->renderOffset;
}

/***********************************************************************
 * ReaderFunc
 ***********************************************************************
 *
 **********************************************************************/
static void ReaderFunc( void * _r )
{
    hb_reader_t  * r = _r;
    hb_fifo_t   ** fifos;
    hb_buffer_t  * buf;
    hb_list_t    * list;
    int            n;
    int            chapter = -1;
    int            chapter_end = r->job->chapter_end;

    if ( r->title->type == HB_DVD_TYPE )
    {
        if ( !( r->dvd = hb_dvd_init( r->title->path ) ) )
            return;
    }
    else if ( r->title->type == HB_STREAM_TYPE )
    {
        if ( !( r->stream = hb_stream_open( r->title->path, r->title ) ) )
            return;
    }
    else
    {
        // Unknown type, should never happen
        return;
    }

    if (r->dvd)
    {
        /*
         * XXX this code is a temporary hack that should go away if/when
         *     chapter merging goes away in libhb/dvd.c
         * map the start and end chapter numbers to on-media chapter
         * numbers since chapter merging could cause the handbrake numbers
         * to diverge from the media numbers and, if our chapter_end is after
         * a media chapter that got merged, we'll stop ripping too early.
         */
        int start = r->job->chapter_start;
        hb_chapter_t *chap = hb_list_item( r->title->list_chapter, chapter_end - 1 );

        chapter_end = chap->index;
        if (start > 1)
        {
           chap = hb_list_item( r->title->list_chapter, start - 1 );
           start = chap->index;
        }
        /* end chapter mapping XXX */

        if( !hb_dvd_start( r->dvd, r->title, start ) )
        {
            hb_dvd_close( &r->dvd );
            return;
        }
        if (r->job->angle)
        {
            hb_dvd_set_angle( r->dvd, r->job->angle );
        }

        if ( r->job->start_at_preview )
        {
            // XXX code from DecodePreviews - should go into its own routine
            hb_dvd_seek( r->dvd, (float)r->job->start_at_preview /
                         ( r->job->seek_points ? ( r->job->seek_points + 1.0 ) : 11.0 ) );
        }
    }
    else if ( r->stream && r->job->start_at_preview )
    {
        
        // XXX code from DecodePreviews - should go into its own routine
        hb_stream_seek( r->stream, (float)( r->job->start_at_preview - 1 ) /
                        ( r->job->seek_points ? ( r->job->seek_points + 1.0 ) : 11.0 ) );

    } 
    else if( r->stream )
    {
        /*
         * Standard stream, seek to the starting chapter, if set, and track the
         * end chapter so that we end at the right time.
         */
        int start = r->job->chapter_start;
        hb_chapter_t *chap = hb_list_item( r->title->list_chapter, chapter_end - 1 );
        
        chapter_end = chap->index;
        if (start > 1)
        {
            chap = hb_list_item( r->title->list_chapter, start - 1 );
            start = chap->index;
        }
        
        /*
         * Seek to the start chapter.
         */
        hb_stream_seek_chapter( r->stream, start );
    }

    list  = hb_list_init();
    hb_buffer_t *ps = hb_buffer_init( HB_DVD_READ_BUFFER_SIZE );

    while( !*r->die && !r->job->done )
    {
        if (r->dvd)
            chapter = hb_dvd_chapter( r->dvd );
        else if (r->stream)
            chapter = hb_stream_chapter( r->stream );

        if( chapter < 0 )
        {
            hb_log( "reader: end of the title reached" );
            break;
        }
        if( chapter > chapter_end )
        {
            hb_log( "reader: end of chapter %d (media %d) reached at media chapter %d",
                    r->job->chapter_end, chapter_end, chapter );
            break;
        }

        if (r->dvd)
        {
          if( !hb_dvd_read( r->dvd, ps ) )
          {
              break;
          }
        }
        else if (r->stream)
        {
          if ( !hb_stream_read( r->stream, ps ) )
          {
            break;
          }
        }

        if( r->job->indepth_scan )
        {
            /*
             * Need to update the progress during a subtitle scan
             */
            hb_state_t state;

#define p state.param.working

            state.state = HB_STATE_WORKING;
            p.progress = (double)chapter / (double)r->job->chapter_end;
            if( p.progress > 1.0 )
            {
                p.progress = 1.0;
            }
            p.rate_avg = 0.0;
            p.hours    = -1;
            p.minutes  = -1;
            p.seconds  = -1;
            hb_set_state( r->job->h, &state );
        }

        (hb_demux[r->title->demuxer])( ps, list, &r->demux );

        while( ( buf = hb_list_item( list, 0 ) ) )
        {
            hb_list_rem( list, buf );
            fifos = GetFifoForId( r->job, buf->id );

            if ( fifos && ! r->saw_video )
            {
                // The first data packet with a PTS from an audio or video stream
                // that we're decoding defines 'time zero'. Discard packets until
                // we get one.
                if ( buf->start != -1 && buf->renderOffset != -1 &&
                     ( buf->id == r->title->video_id || is_audio( r, buf->id ) ) )
                {
                    // force a new scr offset computation
                    r->scr_changes = r->demux.scr_changes - 1;
                    // create a stream state if we don't have one so the
                    // offset will get computed correctly.
                    id_to_st( r, buf );
                    r->saw_video = 1;
                    hb_log( "reader: first SCR %"PRId64" id %d DTS %"PRId64,
                            r->demux.last_scr, buf->id, buf->renderOffset );
                }
                else
                {
                    fifos = NULL;
                }
            }
            if( fifos )
            {
                if ( buf->renderOffset != -1 )
                {
                    if ( r->scr_changes == r->demux.scr_changes )
                    {
                        // This packet is referenced to the same SCR as the last.
                        // Adjust timestamp to remove the System Clock Reference
                        // offset then update the average inter-packet time
                        // for this stream.
                        buf->renderOffset -= r->scr_offset;
                        update_ipt( r, buf );
                    }
                    else
                    {
                        // This is the first audio or video packet after an SCR
                        // change. Compute a new scr offset that would make this
                        // packet follow the last of this stream with the correct
                        // average spacing.
                        stream_timing_t *st = find_st( r, buf );

                        if ( st )
                        {
                            // if this is the video stream and we don't have
                            // audio yet or this is an audio stream
                            // generate a new scr
                            if ( st->is_audio ||
                                 ( st == r->stream_timing && !r->saw_audio ) )
                            {
                                new_scr_offset( r, buf );
                            }
                            else
                            {
                                // defer the scr change until we get some
                                // audio since audio has a timestamp per
                                // frame but video & subtitles don't. Clear
                                // the timestamps so the decoder will generate
                                // them from the frame durations.
                                if ( st != r->stream_timing )
                                {
                                    // not a video stream so it's probably
                                    // subtitles - the best we can do is to
                                    // line it up with the last video packet.
                                    buf->start = r->stream_timing->last;
                                }
                                else
                                {
                                    buf->start = -1;
                                    buf->renderOffset = -1;
                                }
                            }
                        }
                        else
                        {
                            // we got a new scr at the same time as the first
                            // packet of a stream we've never seen before. We
                            // have no idea what the timing should be so toss
                            // this buffer & wait for a stream we've already seen.
                            // add stream to list of streams we have seen
                            id_to_st( r, buf );
                            hb_buffer_close( &buf );
                            continue;
                        }
                    }
                }
                if ( buf->start != -1 )
                {
                    buf->start -= r->scr_offset;
                    if ( r->job->pts_to_stop && buf->start > r->job->pts_to_stop )
                    {
                        // we're doing a subset of the input and we've hit the
                        // stopping point.
                        hb_buffer_close( &buf );
                        goto done;
                    }
                }

                buf->sequence = r->sequence++;
                /* if there are mutiple output fifos, send a copy of the
                 * buffer down all but the first (we have to not ship the
                 * original buffer or we'll race with the thread that's
                 * consuming the buffer & inject garbage into the data stream). */
                for( n = 1; fifos[n] != NULL; n++)
                {
                    hb_buffer_t *buf_copy = hb_buffer_init( buf->size );
                    hb_buffer_copy_settings( buf_copy, buf );
                    memcpy( buf_copy->data, buf->data, buf->size );
                    push_buf( r, fifos[n], buf_copy );
                }
                push_buf( r, fifos[0], buf );
            }
            else
            {
                hb_buffer_close( &buf );
            }
        }
    }

  done:
    // send empty buffers downstream to video & audio decoders to signal we're done.
    push_buf( r, r->job->fifo_mpeg2, hb_buffer_init(0) );

    hb_audio_t *audio;
    for( n = 0; ( audio = hb_list_item( r->job->title->list_audio, n ) ); ++n )
    {
        if ( audio->priv.fifo_in )
            push_buf( r, audio->priv.fifo_in, hb_buffer_init(0) );
    }

    hb_subtitle_t *subtitle;
    for( n = 0; ( subtitle = hb_list_item( r->job->title->list_subtitle, n ) ); ++n )
    {
        if ( subtitle->fifo_in && subtitle->source == VOBSUB)
            push_buf( r, subtitle->fifo_in, hb_buffer_init(0) );
    }

    hb_list_empty( &list );
    hb_buffer_close( &ps );
    if (r->dvd)
    {
        hb_dvd_stop( r->dvd );
        hb_dvd_close( &r->dvd );
    }
    else if (r->stream)
    {
        hb_stream_close(&r->stream);
    }

    if ( r->stream_timing )
    {
        free( r->stream_timing );
    }

    hb_log( "reader: done. %d scr changes", r->demux.scr_changes );
    if ( r->demux.dts_drops )
    {
        hb_log( "reader: %d drops because DTS out of range", r->demux.dts_drops );
    }

    free( r );
    _r = NULL;
}

/***********************************************************************
 * GetFifoForId
 ***********************************************************************
 *
 **********************************************************************/
static hb_fifo_t ** GetFifoForId( hb_job_t * job, int id )
{
    hb_title_t    * title = job->title;
    hb_audio_t    * audio;
    hb_subtitle_t * subtitle;
    int             i, n, count;
    static hb_fifo_t * fifos[100];

    memset(fifos, 0, sizeof(fifos));

    if( id == title->video_id )
    {
        if( job->indepth_scan )
        {
            /*
             * Ditch the video here during the indepth scan until
             * we can improve the MPEG2 decode performance.
             */
            return NULL;
        }
        else
        {
            fifos[0] = job->fifo_mpeg2;
            return fifos;
        }
    }

    n = 0;
    count = hb_list_count( title->list_subtitle );
    count = count > 99 ? 99 : count;
    for( i=0; i < count; i++ ) {
        subtitle =  hb_list_item( title->list_subtitle, i );
        if (id == subtitle->id) {
            subtitle->hits++;
            if( !job->indepth_scan || job->select_subtitle_config.force )
            {
                /*
                 * Pass the subtitles to be processed if we are not scanning, or if
                 * we are scanning and looking for forced subs, then pass them up
                 * to decode whether the sub is a forced one.
                 */
                fifos[n++] = subtitle->fifo_in;
            }
        }
    }
    if ( n != 0 )
    {
        return fifos;
    }
    
    if( !job->indepth_scan )
    {
        n = 0;
        for( i = 0; i < hb_list_count( title->list_audio ); i++ )
        {
            audio = hb_list_item( title->list_audio, i );
            if( id == audio->id )
            {
                fifos[n++] = audio->priv.fifo_in;
            }
        }

        if( n != 0 )
        {
            return fifos;
        }
    }

    return NULL;
}