/*
  * SCC muxer
  * Copyright (c) 2017 Paul B Mahol
  *
  * 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 "libavutil/log.h"
 #include "libavutil/intreadwrite.h"
 
 typedef struct SCCContext {
     int prev_h, prev_m, prev_s, prev_f;
     int inside;
     int n;
 } SCCContext;
 
 static int scc_write_header(AVFormatContext *avf)
 {
     SCCContext *scc = avf->priv_data;
 
     if (avf->nb_streams != 1 ||
         avf->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
         av_log(avf, AV_LOG_ERROR,
                "SCC supports only a single subtitles stream.\n");
         return AVERROR(EINVAL);
     }
     if (avf->streams[0]->codecpar->codec_id != AV_CODEC_ID_EIA_608) {
         av_log(avf, AV_LOG_ERROR,
                "Unsupported subtitles codec: %s\n",
                avcodec_get_name(avf->streams[0]->codecpar->codec_id));
         return AVERROR(EINVAL);
     }
     avpriv_set_pts_info(avf->streams[0], 64, 1, 1000);
     avio_printf(avf->pb, "Scenarist_SCC V1.0\n");
 
     scc->prev_h = scc->prev_m = scc->prev_s = scc->prev_f = -1;
     scc->inside = 0;
 
     return 0;
 }
 
 static int scc_write_packet(AVFormatContext *avf, AVPacket *pkt)
 {
     SCCContext *scc = avf->priv_data;
     int64_t pts = pkt->pts;
     int i, h, m, s, f;
 
     if (pts == AV_NOPTS_VALUE) {
         av_log(avf, AV_LOG_WARNING,
                "Insufficient timestamps.\n");
         return 0;
     }
 
     h = (int)(pts / (3600000));
     m = (int)(pts / (60000)) % 60;
     s = (int)(pts /  1000) % 60;
     f = (int)(pts %  1000) / 33;
 
     for (i = 0; i < pkt->size; i+=3) {
         if (pkt->data[i] == 0xfc && ((pkt->data[i + 1] != 0x80 || pkt->data[i + 2] != 0x80)))
             break;
     }
     if (i >= pkt->size)
         return 0;
 
     if (!scc->inside && (scc->prev_h != h || scc->prev_m != m || scc->prev_s != s || scc->prev_f != f)) {
         avio_printf(avf->pb, "\n%02d:%02d:%02d:%02d\t", h, m, s, f);
         scc->inside = 1;
     }
     for (i = 0; i < pkt->size; i+=3) {
         if (i + 3 > pkt->size)
             break;
 
         if (pkt->data[i] != 0xfc || (pkt->data[i + 1] == 0x80 && pkt->data[i + 2] == 0x80))
             continue;
         if (!scc->inside) {
             avio_printf(avf->pb, "\n%02d:%02d:%02d:%02d\t", h, m, s, f);
             scc->inside = 1;
         }
         if (scc->n > 0)
             avio_printf(avf->pb, " ");
         avio_printf(avf->pb, "%02x%02x", pkt->data[i + 1], pkt->data[i + 2]);
         scc->n++;
     }
     if (scc->inside && (scc->prev_h != h || scc->prev_m != m || scc->prev_s != s || scc->prev_f != f)) {
         avio_printf(avf->pb, "\n");
         scc->n = 0;
         scc->inside = 0;
     }
 
     scc->prev_h = h;
     scc->prev_m = m;
     scc->prev_s = s;
     scc->prev_f = f;
     return 0;
 }
 
 AVOutputFormat ff_scc_muxer = {
     .name           = "scc",
     .long_name      = NULL_IF_CONFIG_SMALL("Scenarist Closed Captions"),
     .extensions     = "scc",
     .priv_data_size = sizeof(SCCContext),
     .write_header   = scc_write_header,
     .write_packet   = scc_write_packet,
     .flags          = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS | AVFMT_TS_NONSTRICT,
     .subtitle_codec = AV_CODEC_ID_EIA_608,
 };