/*
  * 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
  * SubViewer subtitle demuxer
  * @see https://en.wikipedia.org/wiki/SubViewer
  */
 
 #include "avformat.h"
 #include "internal.h"
 #include "subtitles.h"

 #include "libavcodec/internal.h"

 #include "libavutil/avstring.h"
 #include "libavutil/bprint.h"
 #include "libavutil/intreadwrite.h"
 
 typedef struct {
     FFDemuxSubtitlesQueue q;
 } SubViewerContext;
 
 static int subviewer_probe(AVProbeData *p)
 {
     char c;
     const unsigned char *ptr = p->buf;
 
     if (AV_RB24(ptr) == 0xEFBBBF)
         ptr += 3;  /* skip UTF-8 BOM */
     if (sscanf(ptr, "%*u:%*u:%*u.%*u,%*u:%*u:%*u.%*u%c", &c) == 1)
         return AVPROBE_SCORE_MAX/2;
     if (!strncmp(ptr, "[INFORMATION]", 13))
         return AVPROBE_SCORE_MAX/3;
     return 0;
 }
 
 static int read_ts(const char *s, int64_t *start, int *duration)
 {
     int64_t end;
     int hh1, mm1, ss1, ms1;
     int hh2, mm2, ss2, ms2;
 
     if (sscanf(s, "%u:%u:%u.%u,%u:%u:%u.%u",
                &hh1, &mm1, &ss1, &ms1, &hh2, &mm2, &ss2, &ms2) == 8) {

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

         *duration = end - *start;
         return 0;
     }
     return -1;
 }
 
 static int subviewer_read_header(AVFormatContext *s)
 {
     SubViewerContext *subviewer = s->priv_data;
     AVStream *st = avformat_new_stream(s, NULL);
     AVBPrint header;

     int res = 0, new_event = 1;
     int64_t pts_start = AV_NOPTS_VALUE;
     int duration = -1;
     AVPacket *sub = NULL;

 
     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_SUBVIEWER;

 
     av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);
 
     while (!url_feof(s->pb)) {
         char line[2048];

         int64_t pos = 0;

         int len = ff_get_line(s->pb, line, sizeof(line));
 
         if (!len)
             break;
 

         line[strcspn(line, "\r\n")] = 0;
 

         if (line[0] == '[' && strncmp(line, "[br]", 4)) {
 
             /* ignore event style, XXX: add to side_data? */
             if (strstr(line, "[COLF]") || strstr(line, "[SIZE]") ||
                 strstr(line, "[FONT]") || strstr(line, "[STYLE]"))
                 continue;
 
             if (!st->codec->extradata) { // header not finalized yet

                 av_bprintf(&header, "%s\n", line);

                 if (!strncmp(line, "[END INFORMATION]", 17) || !strncmp(line, "[SUBTITLE]", 10)) {
                     /* end of header */

                     res = avpriv_bprint_to_extradata(st->codec, &header);

                     if (res < 0)

                         goto end;
                 } else if (strncmp(line, "[INFORMATION]", 13)) {
                     /* assume file metadata at this point */
                     int i, j = 0;
                     char key[32], value[128];
 
                     for (i = 1; i < sizeof(key) - 1 && line[i] && line[i] != ']'; i++)
                         key[i - 1] = av_tolower(line[i]);
                     key[i - 1] = 0;
 
                     if (line[i] == ']')
                         i++;
                     while (line[i] == ' ')
                         i++;

                     while (j < sizeof(value) - 1 && line[i] && line[i] != ']')

                         value[j++] = line[i++];
                     value[j] = 0;
 
                     av_dict_set(&s->metadata, key, value, 0);
                 }
             }

         } else if (read_ts(line, &pts_start, &duration) >= 0) {
             new_event = 1;
             pos = avio_tell(s->pb);
         } else if (*line) {
             if (!new_event) {
                 sub = ff_subtitles_queue_insert(&subviewer->q, "\n", 1, 1);
                 if (!sub) {
                     res = AVERROR(ENOMEM);
                     goto end;
                 }
             }
             sub = ff_subtitles_queue_insert(&subviewer->q, line, strlen(line), !new_event);

             if (!sub) {
                 res = AVERROR(ENOMEM);
                 goto end;
             }

             if (new_event) {

                 sub->pos = pos;
                 sub->pts = pts_start;
                 sub->duration = duration;
             }

             new_event = 0;

         }
     }
 
     ff_subtitles_queue_finalize(&subviewer->q);
 
 end:
     av_bprint_finalize(&header, NULL);
     return res;
 }
 
 static int subviewer_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     SubViewerContext *subviewer = s->priv_data;
     return ff_subtitles_queue_read_packet(&subviewer->q, pkt);
 }
 

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

 static int subviewer_read_close(AVFormatContext *s)
 {
     SubViewerContext *subviewer = s->priv_data;
     ff_subtitles_queue_clean(&subviewer->q);
     return 0;
 }
 
 AVInputFormat ff_subviewer_demuxer = {
     .name           = "subviewer",
     .long_name      = NULL_IF_CONFIG_SMALL("SubViewer subtitle format"),
     .priv_data_size = sizeof(SubViewerContext),
     .read_probe     = subviewer_probe,
     .read_header    = subviewer_read_header,
     .read_packet    = subviewer_read_packet,

     .read_seek2     = subviewer_read_seek,

     .read_close     = subviewer_read_close,
     .extensions     = "sub",
 };