/*
  * 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
  * WebVTT subtitle demuxer
  * @see http://dev.w3.org/html5/webvtt/
  */
 
 #include "avformat.h"
 #include "internal.h"
 #include "subtitles.h"
 #include "libavutil/bprint.h"
 #include "libavutil/intreadwrite.h"
 
 typedef struct {
     FFDemuxSubtitlesQueue q;
 } WebVTTContext;
 
 static int webvtt_probe(AVProbeData *p)
 {
     const uint8_t *ptr = p->buf;
 
     if (AV_RB24(ptr) == 0xEFBBBF)
         ptr += 3;  /* skip UTF-8 BOM */
     if (!strncmp(ptr, "WEBVTT", 6) &&
         (!ptr[6] || strchr("\n\r\t ", ptr[6])))
         return AVPROBE_SCORE_MAX;
     return 0;
 }
 
 static int64_t read_ts(const char *s)
 {
     int hh, mm, ss, ms;

     if (sscanf(s, "%u:%u:%u.%u", &hh, &mm, &ss, &ms) == 4) return (hh*3600LL + mm*60LL + ss) * 1000LL + ms;
     if (sscanf(s,    "%u:%u.%u",      &mm, &ss, &ms) == 3) return (            mm*60LL + ss) * 1000LL + ms;

     return AV_NOPTS_VALUE;
 }
 
 static int webvtt_read_header(AVFormatContext *s)
 {
     WebVTTContext *webvtt = s->priv_data;
     AVBPrint header, cue;
     int res = 0;
     AVStream *st = avformat_new_stream(s, NULL);
 
     if (!st)
         return AVERROR(ENOMEM);
     avpriv_set_pts_info(st, 64, 1, 1000);
     st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
     st->codec->codec_id   = AV_CODEC_ID_WEBVTT;
 
     av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);
     av_bprint_init(&cue,    0, AV_BPRINT_SIZE_UNLIMITED);
 
     for (;;) {

         int i;
         int64_t pos;

         AVPacket *sub;

         const char *p, *identifier;

         //const char *settings = NULL;
         int64_t ts_start, ts_end;
 

         ff_subtitles_read_chunk(s->pb, &cue);
 
         if (!cue.len)

             break;
 

         p = identifier = cue.str;
         pos = avio_tell(s->pb);
 

         /* ignore header chunk */
         if (!strncmp(p, "\xEF\xBB\xBFWEBVTT", 9) ||
             !strncmp(p, "WEBVTT", 6))
             continue;
 
         /* optional cue identifier (can be a number like in SRT or some kind of
          * chaptering id), silently skip it */
         for (i = 0; p[i] && p[i] != '\n'; i++) {
             if (!strncmp(p + i, "-->", 3)) {
                 identifier = NULL;
                 break;
             }
         }
         if (identifier)
             p += strcspn(p, "\n");
 
         /* cue timestamps */
         if ((ts_start = read_ts(p)) == AV_NOPTS_VALUE)
             break;
         if (!(p = strstr(p, "-->")))
             break;
         p += 3;
         do p++; while (*p == ' ' || *p == '\t');
         if ((ts_end = read_ts(p)) == AV_NOPTS_VALUE)
             break;
 
         /* optional cue settings, TODO: store in side_data */
         p += strcspn(p, "\n\t ");
         while (*p == '\t' || *p == ' ')
             p++;
         if (*p != '\n') {
             //settings = p;
             p += strcspn(p, "\n");
         }
         if (*p == '\n')
             p++;
 
         /* create packet */

         sub = ff_subtitles_queue_insert(&webvtt->q, p, strlen(p), 0);

         if (!sub) {
             res = AVERROR(ENOMEM);
             goto end;
         }
         sub->pos = pos;
         sub->pts = ts_start;
         sub->duration = ts_end - ts_start;
     }
 
     ff_subtitles_queue_finalize(&webvtt->q);
 
 end:
     av_bprint_finalize(&cue,    NULL);
     av_bprint_finalize(&header, NULL);
     return res;
 }
 
 static int webvtt_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     WebVTTContext *webvtt = s->priv_data;
     return ff_subtitles_queue_read_packet(&webvtt->q, pkt);
 }
 

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

 static int webvtt_read_close(AVFormatContext *s)
 {
     WebVTTContext *webvtt = s->priv_data;
     ff_subtitles_queue_clean(&webvtt->q);
     return 0;
 }
 
 AVInputFormat ff_webvtt_demuxer = {
     .name           = "webvtt",
     .long_name      = NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
     .priv_data_size = sizeof(WebVTTContext),
     .read_probe     = webvtt_probe,
     .read_header    = webvtt_read_header,
     .read_packet    = webvtt_read_packet,

     .read_seek2     = webvtt_read_seek,

     .read_close     = webvtt_read_close,
     .extensions     = "vtt",
 };