/*
  * MicroDVD subtitle demuxer
  * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>

  * Copyright (c) 2012  Clément Bœsch <u pkh me>

  *
  * 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
  */
 
 #include "avformat.h"
 #include "internal.h"

 #include "subtitles.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/opt.h"

 
 #define MAX_LINESIZE 2048
 
 
 typedef struct {

     const AVClass *class;

     FFDemuxSubtitlesQueue q;

     AVRational frame_rate;

 } MicroDVDContext;
 
 
 static int microdvd_probe(AVProbeData *p)
 {

     unsigned char c;
     const uint8_t *ptr = p->buf;

     int i;
 
     if (AV_RB24(ptr) == 0xEFBBBF)
         ptr += 3;  /* skip UTF-8 BOM */
 
     for (i=0; i<3; i++) {
         if (sscanf(ptr, "{%*d}{}%c",     &c) != 1 &&
             sscanf(ptr, "{%*d}{%*d}%c",  &c) != 1 &&
             sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
             return 0;

         ptr += ff_subtitles_next_line(ptr);

     }
     return AVPROBE_SCORE_MAX;
 }
 
 static int64_t get_pts(const char *buf)
 {
     int frame;
     char c;
 
     if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)
         return frame;
     return AV_NOPTS_VALUE;
 }
 

 static int get_duration(const char *buf)
 {
     int frame_start, frame_end;
 
     if (sscanf(buf, "{%d}{%d}", &frame_start, &frame_end) == 2)
         return frame_end - frame_start;

     return -1;

 }
 

 static const char *bom = "\xEF\xBB\xBF";
 

 static int microdvd_read_header(AVFormatContext *s)

 {

     AVRational pts_info = (AVRational){ 2997, 125 };  /* default: 23.976 fps */

     MicroDVDContext *microdvd = s->priv_data;

     AVStream *st = avformat_new_stream(s, NULL);
     int i = 0;

     char line_buf[MAX_LINESIZE];

     int has_real_fps = 0;

 
     if (!st)
         return AVERROR(ENOMEM);
 

     while (!avio_feof(s->pb)) {

         char *p;

         AVPacket *sub;
         int64_t pos = avio_tell(s->pb);

         int len = ff_get_line(s->pb, line_buf, sizeof(line_buf));
         char *line = line_buf;
 
         if (!strncmp(line, bom, 3))
             line += 3;
         p = line;

         if (!len)

             break;

         line[strcspn(line, "\r\n")] = 0;
         if (i++ < 3) {

             int frame;
             double fps;
             char c;
 
             if ((sscanf(line, "{%d}{}%6lf",    &frame, &fps) == 2 ||
                  sscanf(line, "{%d}{%*d}%6lf", &frame, &fps) == 2)

                 && frame <= 1 && fps > 3 && fps < 100) {

                 pts_info = av_d2q(fps, 100000);

                 has_real_fps = 1;

                 continue;

             }

             if (!st->codecpar->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {
                 st->codecpar->extradata = av_strdup(line + 11);
                 if (!st->codecpar->extradata)

                     return AVERROR(ENOMEM);

                 st->codecpar->extradata_size = strlen(st->codecpar->extradata) + 1;

                 continue;

             }
         }

 #define SKIP_FRAME_ID                                       \
     p = strchr(p, '}');                                     \
     if (!p) {                                               \
         av_log(s, AV_LOG_WARNING, "Invalid event \"%s\""    \
                " at line %d\n", line, i);                   \
         continue;                                           \
     }                                                       \
     p++
         SKIP_FRAME_ID;
         SKIP_FRAME_ID;
         if (!*p)
             continue;
         sub = ff_subtitles_queue_insert(&microdvd->q, p, strlen(p), 0);

         if (!sub)
             return AVERROR(ENOMEM);
         sub->pos = pos;

         sub->pts = get_pts(line);
         sub->duration = get_duration(line);

     }

     ff_subtitles_queue_finalize(s, &microdvd->q);

     if (has_real_fps) {
         /* export the FPS info only if set in the file */
         microdvd->frame_rate = pts_info;
     } else if (microdvd->frame_rate.num) {
         /* fallback on user specified frame rate */
         pts_info = microdvd->frame_rate;
     }

     avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num);

     st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
     st->codecpar->codec_id   = AV_CODEC_ID_MICRODVD;

     return 0;
 }
 
 static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     MicroDVDContext *microdvd = s->priv_data;
     return ff_subtitles_queue_read_packet(&microdvd->q, pkt);
 }
 

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

 static int microdvd_read_close(AVFormatContext *s)
 {
     MicroDVDContext *microdvd = s->priv_data;
     ff_subtitles_queue_clean(&microdvd->q);
     return 0;

 }
 

 
 #define OFFSET(x) offsetof(MicroDVDContext, x)
 #define SD AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_DECODING_PARAM
 static const AVOption microdvd_options[] = {
     { "subfps", "set the movie frame rate fallback", OFFSET(frame_rate), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, SD },
     { NULL }
 };
 
 static const AVClass microdvd_class = {
     .class_name = "microdvddec",
     .item_name  = av_default_item_name,
     .option     = microdvd_options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 AVInputFormat ff_microdvd_demuxer = {
     .name           = "microdvd",
     .long_name      = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
     .priv_data_size = sizeof(MicroDVDContext),
     .read_probe     = microdvd_probe,
     .read_header    = microdvd_read_header,
     .read_packet    = microdvd_read_packet,

     .read_seek2     = microdvd_read_seek,

     .read_close     = microdvd_read_close,

     .priv_class     = &microdvd_class,

 };