/*
  * 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
  * JACOsub subtitle demuxer
  * @see http://unicorn.us.com/jacosub/jscripts.html
  * @todo Support P[ALETTE] directive.
  */
 
 #include "avformat.h"
 #include "internal.h"

 #include "subtitles.h"

 #include "libavcodec/internal.h"

 #include "libavcodec/jacosub.h"
 #include "libavutil/avstring.h"
 #include "libavutil/bprint.h"
 #include "libavutil/intreadwrite.h"
 
 typedef struct {
     int shift;
     unsigned timeres;

     FFDemuxSubtitlesQueue q;

 } JACOsubContext;
 
 static int timed_line(const char *ptr)
 {
     char c;
     return (sscanf(ptr, "%*u:%*u:%*u.%*u %*u:%*u:%*u.%*u %c", &c) == 1 ||
             sscanf(ptr, "@%*u @%*u %c",                       &c) == 1);
 }
 
 static int jacosub_probe(AVProbeData *p)
 {
     const char *ptr     = p->buf;
     const char *ptr_end = p->buf + p->buf_size;
 
     if (AV_RB24(ptr) == 0xEFBBBF)
         ptr += 3; /* skip UTF-8 BOM */
 
     while (ptr < ptr_end) {
         while (jss_whitespace(*ptr))
             ptr++;

         if (*ptr != '#' && *ptr != '\n') {
             if (timed_line(ptr))

                 return AVPROBE_SCORE_EXTENSION + 1;

             return 0;
         }

         ptr += ff_subtitles_next_line(ptr);

     }
     return 0;
 }
 
 static const char * const cmds[] = {
     "CLOCKPAUSE",
     "DIRECTIVE",
     "FONT",
     "HRES",
     "INCLUDE",
     "PALETTE",
     "QUANTIZE",
     "RAMP",
     "SHIFT",
     "TIMERES",
 };
 
 static int get_jss_cmd(char k)
 {
     int i;
 
     k = av_toupper(k);
     for (i = 0; i < FF_ARRAY_ELEMS(cmds); i++)
         if (k == cmds[i][0])
             return i;
     return -1;
 }
 
 static int jacosub_read_close(AVFormatContext *s)
 {
     JACOsubContext *jacosub = s->priv_data;

     ff_subtitles_queue_clean(&jacosub->q);

     return 0;
 }
 
 static const char *read_ts(JACOsubContext *jacosub, const char *buf,

                            int64_t *start, int *duration)

 {
     int len;
     unsigned hs, ms, ss, fs; // hours, minutes, seconds, frame start
     unsigned he, me, se, fe; // hours, minutes, seconds, frame end

     int ts_start, ts_end;

 
     /* timed format */
     if (sscanf(buf, "%u:%u:%u.%u %u:%u:%u.%u %n",
                &hs, &ms, &ss, &fs,
                &he, &me, &se, &fe, &len) == 8) {

         ts_start = (hs*3600 + ms*60 + ss) * jacosub->timeres + fs;
         ts_end   = (he*3600 + me*60 + se) * jacosub->timeres + fe;

         goto shift_and_ret;
     }
 
     /* timestamps format */

     if (sscanf(buf, "@%u @%u %n", &ts_start, &ts_end, &len) == 2)

         goto shift_and_ret;
 
     return NULL;
 
 shift_and_ret:

     ts_start  = (ts_start + jacosub->shift) * 100 / jacosub->timeres;
     ts_end    = (ts_end   + jacosub->shift) * 100 / jacosub->timeres;
     *start    = ts_start;
     *duration = ts_start + ts_end;

     return buf + len;
 }
 
 static int get_shift(int timeres, const char *buf)
 {
     int sign = 1;
     int a = 0, b = 0, c = 0, d = 0;
 #define SSEP "%*1[.:]"
     int n = sscanf(buf, "%d"SSEP"%d"SSEP"%d"SSEP"%d", &a, &b, &c, &d);
 #undef SSEP
 
     if (*buf == '-' || a < 0) {
         sign = -1;
         a = FFABS(a);
     }
 
     switch (n) {
     case 4: return sign * ((a*3600 + b*60 + c) * timeres + d);
     case 3: return sign * ((         a*60 + b) * timeres + c);
     case 2: return sign * ((                a) * timeres + b);
     }
 
     return 0;
 }
 
 static int jacosub_read_header(AVFormatContext *s)
 {
     AVBPrint header;
     AVIOContext *pb = s->pb;
     char line[JSS_MAX_LINESIZE];
     JACOsubContext *jacosub = s->priv_data;
     int shift_set = 0; // only the first shift matters
     int merge_line = 0;

     int i, ret;

 
     AVStream *st = avformat_new_stream(s, 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_JACOSUB;

 
     jacosub->timeres = 30;
 
     av_bprint_init(&header, 1024+FF_INPUT_BUFFER_PADDING_SIZE, 4096);
 
     while (!url_feof(pb)) {
         int cmd_len;
         const char *p = line;
         int64_t pos = avio_tell(pb);

         int len = ff_get_line(pb, line, sizeof(line));

 
         p = jss_skip_whitespace(p);
 
         /* queue timed line */
         if (merge_line || timed_line(p)) {

             AVPacket *sub;
 
             sub = ff_subtitles_queue_insert(&jacosub->q, line, len, merge_line);
             if (!sub)
                 return AVERROR(ENOMEM);
             sub->pos = pos;

             merge_line = len > 1 && !strcmp(&line[len - 2], "\\\n");
             continue;
         }
 
         /* skip all non-compiler commands and focus on the command */
         if (*p != '#')
             continue;
         p++;
         i = get_jss_cmd(p[0]);
         if (i == -1)
             continue;
 
         /* trim command + spaces */
         cmd_len = strlen(cmds[i]);
         if (av_strncasecmp(p, cmds[i], cmd_len) == 0)
             p += cmd_len;
         else
             p++;
         p = jss_skip_whitespace(p);
 
         /* handle commands which affect the whole script */
         switch (cmds[i][0]) {
         case 'S': // SHIFT command affect the whole script...
             if (!shift_set) {
                 jacosub->shift = get_shift(jacosub->timeres, p);
                 shift_set = 1;
             }
             av_bprintf(&header, "#S %s", p);
             break;
         case 'T': // ...but must be placed after TIMERES
             jacosub->timeres = strtol(p, NULL, 10);

             if (!jacosub->timeres)
                 jacosub->timeres = 30;
             else
                 av_bprintf(&header, "#T %s", p);

             break;
         }
     }
 
     /* general/essential directives in the extradata */

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

     if (ret < 0)
         return ret;

 
     /* SHIFT and TIMERES affect the whole script so packet timing can only be
      * done in a second pass */

     for (i = 0; i < jacosub->q.nb_subs; i++) {
         AVPacket *sub = &jacosub->q.subs[i];
         read_ts(jacosub, sub->data, &sub->pts, &sub->duration);

     }

     ff_subtitles_queue_finalize(&jacosub->q);

 
     return 0;
 }
 
 static int jacosub_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     JACOsubContext *jacosub = s->priv_data;

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

 }
 

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

 AVInputFormat ff_jacosub_demuxer = {
     .name           = "jacosub",
     .long_name      = NULL_IF_CONFIG_SMALL("JACOsub subtitle format"),
     .priv_data_size = sizeof(JACOsubContext),
     .read_probe     = jacosub_probe,
     .read_header    = jacosub_read_header,
     .read_packet    = jacosub_read_packet,

     .read_seek2     = jacosub_read_seek,

     .read_close     = jacosub_read_close,
 };