/*
  * LRC lyrics file format decoder
  * Copyright (c) 2014 StarBrilliant <m13253@hotmail.com>
  *
  * 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 <inttypes.h>
 #include <stdint.h>
 #include <string.h>
 
 #include "avformat.h"
 #include "internal.h"
 #include "lrc.h"
 #include "metadata.h"
 #include "subtitles.h"
 #include "version.h"
 #include "libavutil/bprint.h"
 #include "libavutil/dict.h"
 #include "libavutil/log.h"
 #include "libavutil/macros.h"
 
 static int lrc_write_header(AVFormatContext *s)
 {
     const AVDictionaryEntry *metadata_item;
 
     if(s->nb_streams != 1 ||
        s->streams[0]->codec->codec_type != AVMEDIA_TYPE_SUBTITLE) {
         av_log(s, AV_LOG_ERROR,
                "LRC supports only a single subtitle stream.\n");
         return AVERROR(EINVAL);
     }
     if(s->streams[0]->codec->codec_id != AV_CODEC_ID_SUBRIP &&
        s->streams[0]->codec->codec_id != AV_CODEC_ID_TEXT) {
         av_log(s, AV_LOG_ERROR, "Unsupported subtitle codec: %s\n",
                avcodec_get_name(s->streams[0]->codec->codec_id));
         return AVERROR(EINVAL);
     }
     avpriv_set_pts_info(s->streams[0], 64, 1, 100);
 
     ff_metadata_conv_ctx(s, ff_lrc_metadata_conv, NULL);
     if(!(s->flags & AVFMT_FLAG_BITEXACT)) { // avoid breaking regression tests
         /* LRC provides a metadata slot for specifying encoder version
          * in addition to encoder name. We will store LIBAVFORMAT_VERSION
          * to it.
          */
         av_dict_set(&s->metadata, "ve", AV_STRINGIFY(LIBAVFORMAT_VERSION), 0);
     } else {
         av_dict_set(&s->metadata, "ve", NULL, 0);
     }
     for(metadata_item = NULL;
        (metadata_item = av_dict_get(s->metadata, "", metadata_item,

                                     AV_DICT_IGNORE_SUFFIX));) {

         char *delim;
         if(!metadata_item->value[0]) {
             continue;
         }

         while((delim = strchr(metadata_item->value, '\n'))) {

             *delim = ' ';
         }

         while((delim = strchr(metadata_item->value, '\r'))) {

             *delim = ' ';
         }
         avio_printf(s->pb, "[%s:%s]\n",
                     metadata_item->key, metadata_item->value);
     }
     avio_printf(s->pb, "\n");
     return 0;
 }
 
 static int lrc_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     if(pkt->pts != AV_NOPTS_VALUE) {
         char *data = av_malloc(pkt->size + 1);
         char *line;
         char *delim;
 
         if(!data) {
             return AVERROR(ENOMEM);
         }
         memcpy(data, pkt->data, pkt->size);
         data[pkt->size] = '\0';
 
         for(delim = data + pkt->size - 1;
             delim >= data && (delim[0] == '\n' || delim[0] == '\r'); delim--) {
             delim[0] = '\0'; // Strip last empty lines
         }
         line = data;
         while(line[0] == '\n' || line[0] == '\r') {
             line++; // Skip first empty lines
         }
 
         while(line) {
             delim = strchr(line, '\n');
             if(delim) {
                 if(delim > line && delim[-1] == '\r') {
                     delim[-1] = '\0';
                 }
                 delim[0] = '\0';
                 delim++;
             }
             if(line[0] == '[') {
                 av_log(s, AV_LOG_WARNING,
                        "Subtitle starts with '[', may cause problems with LRC format.\n");
             }
 
             if(pkt->pts >= 0) {
                 avio_printf(s->pb, "[%02"PRId64":%02"PRId64".%02"PRId64"]",
                             (pkt->pts / 6000),
                             ((pkt->pts / 100) % 60),
                             (pkt->pts % 100));
             } else {
                 /* Offset feature of LRC can easily make pts negative,
                  * we just output it directly and let the player drop it. */
                 avio_printf(s->pb, "[-%02"PRId64":%02"PRId64".%02"PRId64"]",
                             (-pkt->pts) / 6000,
                             ((-pkt->pts) / 100) % 60,
                             (-pkt->pts) % 100);
             }
             avio_printf(s->pb, "%s\n", line);
             line = delim;
         }
         av_free(data);
     }
     return 0;
 }
 
 AVOutputFormat ff_lrc_muxer = {
     .name           = "lrc",
     .long_name      = NULL_IF_CONFIG_SMALL("LRC lyrics"),
     .extensions     = "lrc",
     .priv_data_size = 0,
     .write_header   = lrc_write_header,
     .write_packet   = lrc_write_packet,
     .flags          = AVFMT_VARIABLE_FPS | AVFMT_GLOBALHEADER |
                       AVFMT_TS_NEGATIVE | AVFMT_TS_NONSTRICT,
     .subtitle_codec = AV_CODEC_ID_SUBRIP
 };