/*
  * SSA/ASS demuxer
  * Copyright (c) 2008 Michael Niedermayer

  * Copyright (c) 2014 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
  */
 

 #include <stdint.h>
 

 #include "avformat.h"

 #include "internal.h"

 #include "subtitles.h"

 #include "libavcodec/internal.h"

 #include "libavutil/bprint.h"

 typedef struct ASSContext {

     FFDemuxSubtitlesQueue q;

     unsigned readorder;

 } ASSContext;

 static int ass_probe(AVProbeData *p)

 {

     char buf[13];
     FFTextReader tr;
     ff_text_init_buf(&tr, p->buf, p->buf_size);

     while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n')
         ff_text_r8(&tr);
 

     ff_text_read(&tr, buf, sizeof(buf));
 
     if (!memcmp(buf, "[Script Info]", 13))

         return AVPROBE_SCORE_MAX;
 
     return 0;
 }
 

 static int ass_read_close(AVFormatContext *s)

 {
     ASSContext *ass = s->priv_data;

     ff_subtitles_queue_clean(&ass->q);

     return 0;
 }
 

 static int read_dialogue(ASSContext *ass, AVBPrint *dst, const uint8_t *p,
                          int64_t *start, int *duration)

 {

     int pos = 0;

     int64_t end;
     int hh1, mm1, ss1, ms1;
     int hh2, mm2, ss2, ms2;
 

     if (sscanf(p, "Dialogue: %*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d,%n",

                &hh1, &mm1, &ss1, &ms1,

                &hh2, &mm2, &ss2, &ms2, &pos) >= 8 && pos > 0) {

 
         /* This is not part of the sscanf itself in order to handle an actual
          * number (which would be the Layer) or the form "Marked=N" (which is

          * the old SSA field, now replaced by Layer, and will lead to Layer

          * being 0 here). */
         const int layer = atoi(p + 10);
 

         end    = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
         *start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
         *duration = end - *start;

 
         av_bprint_clear(dst);
         av_bprintf(dst, "%u,%d,%s", ass->readorder++, layer, p + pos);
 
         /* right strip the buffer */
         while (dst->len > 0 &&
                dst->str[dst->len - 1] == '\r' ||
                dst->str[dst->len - 1] == '\n')
             dst->str[--dst->len] = 0;

         return 0;
     }
     return -1;

 }
 

 static int64_t get_line(AVBPrint *buf, FFTextReader *tr)

 {

     int64_t pos = ff_text_pos(tr);

 
     av_bprint_clear(buf);
     for (;;) {

         char c = ff_text_r8(tr);

         if (!c)
             break;
         av_bprint_chars(buf, c, 1);
         if (c == '\n')
             break;
     }
     return pos;

 }
 

 static int ass_read_header(AVFormatContext *s)

 {
     ASSContext *ass = s->priv_data;

     AVBPrint header, line, rline;

     int res = 0;

     AVStream *st;

     FFTextReader tr;

     ff_text_init_avio(s, &tr, s->pb);

     st = avformat_new_stream(s, NULL);

     if (!st)

         return AVERROR(ENOMEM);

     avpriv_set_pts_info(st, 64, 1, 100);

     st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;

     st->codecpar->codec_id   = AV_CODEC_ID_ASS;

     av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);
     av_bprint_init(&line,   0, AV_BPRINT_SIZE_UNLIMITED);

     av_bprint_init(&rline,  0, AV_BPRINT_SIZE_UNLIMITED);

     ass->q.keep_duplicates = 1;
 

     for (;;) {

         int64_t pos = get_line(&line, &tr);

         int64_t ts_start = AV_NOPTS_VALUE;
         int duration = -1;
         AVPacket *sub;

         if (!line.str[0]) // EOF
             break;
 

         if (read_dialogue(ass, &rline, line.str, &ts_start, &duration) < 0) {
             av_bprintf(&header, "%s", line.str);
             continue;
         }
         sub = ff_subtitles_queue_insert(&ass->q, rline.str, rline.len, 0);
         if (!sub) {
             res = AVERROR(ENOMEM);
             goto end;
         }
         sub->pos = pos;
         sub->pts = ts_start;
         sub->duration = duration;

     }
 

     res = ff_bprint_to_codecpar_extradata(st->codecpar, &header);

     if (res < 0)

         goto end;

     ff_subtitles_queue_finalize(s, &ass->q);

 end:

     av_bprint_finalize(&header, NULL);
     av_bprint_finalize(&line,   NULL);
     av_bprint_finalize(&rline,  NULL);

     return res;

 }
 

 static int ass_read_packet(AVFormatContext *s, AVPacket *pkt)

 {
     ASSContext *ass = s->priv_data;

     return ff_subtitles_queue_read_packet(&ass->q, pkt);

 }
 

 static int ass_read_seek(AVFormatContext *s, int stream_index,
                          int64_t min_ts, int64_t ts, int64_t max_ts, int flags)

 {
     ASSContext *ass = s->priv_data;

     return ff_subtitles_queue_seek(&ass->q, s, stream_index,
                                    min_ts, ts, max_ts, flags);

 }
 

 AVInputFormat ff_ass_demuxer = {

     .name           = "ass",

     .long_name      = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),

     .priv_data_size = sizeof(ASSContext),

     .read_probe     = ass_probe,
     .read_header    = ass_read_header,
     .read_packet    = ass_read_packet,
     .read_close     = ass_read_close,
     .read_seek2     = ass_read_seek,

 };