/*
  * Copyright (c) 2012 Clément Bœsch
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg 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.
  *
  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**
  * @file
  * RealText subtitle demuxer
  * @see http://service.real.com/help/library/guides/ProductionGuide/prodguide/htmfiles/realtext.htm
  */
 
 #include "avformat.h"
 #include "internal.h"
 #include "subtitles.h"
 #include "libavutil/avstring.h"
 #include "libavutil/bprint.h"
 #include "libavutil/intreadwrite.h"
 
 typedef struct {
     FFDemuxSubtitlesQueue q;
 } RealTextContext;
 
 static int realtext_probe(AVProbeData *p)
 {
     const unsigned char *ptr = p->buf;
 
     if (AV_RB24(ptr) == 0xEFBBBF)
         ptr += 3;  /* skip UTF-8 BOM */

     return !av_strncasecmp(ptr, "<window", 7) ? AVPROBE_SCORE_EXTENSION : 0;

 }
 
 static int read_ts(const char *s)
 {
     int hh, mm, ss, ms;
 
     if (sscanf(s, "%u:%u:%u.%u", &hh, &mm, &ss, &ms) == 4) return (hh*3600 + mm*60 + ss) * 100 + ms;
     if (sscanf(s, "%u:%u:%u"   , &hh, &mm, &ss     ) == 3) return (hh*3600 + mm*60 + ss) * 100;
     if (sscanf(s,    "%u:%u.%u",      &mm, &ss, &ms) == 3) return (          mm*60 + ss) * 100 + ms;
     if (sscanf(s,    "%u:%u"   ,      &mm, &ss     ) == 2) return (          mm*60 + ss) * 100;
     if (sscanf(s,       "%u.%u",           &ss, &ms) == 2) return (                  ss) * 100 + ms;
     return strtol(s, NULL, 10) * 100;
 }
 
 static int realtext_read_header(AVFormatContext *s)
 {
     RealTextContext *rt = s->priv_data;
     AVStream *st = avformat_new_stream(s, NULL);
     AVBPrint buf;
     char c = 0;
     int res = 0, duration = read_ts("60"); // default duration is 60 seconds
 
     if (!st)
         return AVERROR(ENOMEM);
     avpriv_set_pts_info(st, 64, 1, 100);
     st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;

     st->codec->codec_id   = AV_CODEC_ID_REALTEXT;

 
     av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
 
     while (!url_feof(s->pb)) {
         AVPacket *sub;
         const int64_t pos = avio_tell(s->pb) - (c != 0);
         int n = ff_smil_extract_next_chunk(s->pb, &buf, &c);
 
         if (n == 0)
             break;
 
         if (!av_strncasecmp(buf.str, "<window", 7)) {
             /* save header to extradata */
             const char *p = ff_smil_get_attr_ptr(buf.str, "duration");
 
             if (p)
                 duration = read_ts(p);
             st->codec->extradata = av_strdup(buf.str);
             if (!st->codec->extradata) {
                 res = AVERROR(ENOMEM);
                 goto end;
             }
             st->codec->extradata_size = buf.len + 1;
         } else {
             /* if we just read a <time> tag, introduce a new event, otherwise merge
              * with the previous one */
             int merge = !av_strncasecmp(buf.str, "<time", 5) ? 0 : 1;
             sub = ff_subtitles_queue_insert(&rt->q, buf.str, buf.len, merge);
             if (!sub) {
                 res = AVERROR(ENOMEM);
                 goto end;
             }
             if (!merge) {
                 const char *begin = ff_smil_get_attr_ptr(buf.str, "begin");
                 const char *end   = ff_smil_get_attr_ptr(buf.str, "end");
 
                 sub->pos      = pos;
                 sub->pts      = begin ? read_ts(begin) : 0;
                 sub->duration = end ? (read_ts(end) - sub->pts) : duration;
             }
         }
         av_bprint_clear(&buf);
     }
     ff_subtitles_queue_finalize(&rt->q);
 
 end:
     av_bprint_finalize(&buf, NULL);
     return res;
 }
 
 static int realtext_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     RealTextContext *rt = s->priv_data;
     return ff_subtitles_queue_read_packet(&rt->q, pkt);
 }
 

 static int realtext_read_seek(AVFormatContext *s, int stream_index,
                              int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
 {
     RealTextContext *rt = s->priv_data;
     return ff_subtitles_queue_seek(&rt->q, s, stream_index,
                                    min_ts, ts, max_ts, flags);
 }
 

 static int realtext_read_close(AVFormatContext *s)
 {
     RealTextContext *rt = s->priv_data;
     ff_subtitles_queue_clean(&rt->q);
     return 0;
 }
 
 AVInputFormat ff_realtext_demuxer = {
     .name           = "realtext",
     .long_name      = NULL_IF_CONFIG_SMALL("RealText subtitle format"),
     .priv_data_size = sizeof(RealTextContext),
     .read_probe     = realtext_probe,
     .read_header    = realtext_read_header,
     .read_packet    = realtext_read_packet,

     .read_seek2     = realtext_read_seek,

     .read_close     = realtext_read_close,
     .extensions     = "rt",
 };