/*
  * 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
  * MicroDVD subtitle decoder
  *
  * Based on the specifications found here:
  * https://trac.videolan.org/vlc/ticket/1825#comment:6
  */
 
 #include "libavutil/avstring.h"
 #include "libavutil/parseutils.h"
 #include "libavutil/bprint.h"
 #include "avcodec.h"
 #include "ass.h"
 
 static int indexof(const char *s, int c)
 {
     char *f = strchr(s, c);
     return f ? (f - s) : -1;
 }
 
 struct microdvd_tag {
     char key;
     int persistent;
     uint32_t data1;
     uint32_t data2;
     char *data_string;
     int data_string_len;
 };
 
 #define MICRODVD_PERSISTENT_OFF     0
 #define MICRODVD_PERSISTENT_ON      1
 #define MICRODVD_PERSISTENT_OPENED  2
 
 // Color, Font, Size, cHarset, stYle, Position, cOordinate
 #define MICRODVD_TAGS "cfshyYpo"
 
 static void microdvd_set_tag(struct microdvd_tag *tags, struct microdvd_tag tag)
 {
     int tag_index = indexof(MICRODVD_TAGS, tag.key);
 
     if (tag_index < 0)
         return;
     memcpy(&tags[tag_index], &tag, sizeof(tag));
 }
 
 // italic, bold, underline, strike-through
 #define MICRODVD_STYLES "ibus"
 
 static char *microdvd_load_tags(struct microdvd_tag *tags, char *s)
 {
     while (*s == '{') {
         char *start = s;
         char tag_char = *(s + 1);
         struct microdvd_tag tag = {0};
 
         if (!tag_char || *(s + 2) != ':')
             break;
         s += 3;
 
         switch (tag_char) {
 
         /* Style */
         case 'Y':
             tag.persistent = MICRODVD_PERSISTENT_ON;
         case 'y':
             while (*s && *s != '}') {
                 int style_index = indexof(MICRODVD_STYLES, *s);
 
                 if (style_index >= 0)
                     tag.data1 |= (1 << style_index);
                 s++;
             }
             if (*s != '}')
                 break;
             /* We must distinguish persistent and non-persistent styles
              * to handle this kind of style tags: {y:ib}{Y:us} */
             tag.key = tag_char;
             break;
 
         /* Color */
         case 'C':
             tag.persistent = MICRODVD_PERSISTENT_ON;
         case 'c':

             if (*s == '$')
                 s++;

             tag.data1 = strtol(s, &s, 16) & 0x00ffffff;
             if (*s != '}')
                 break;
             tag.key = 'c';
             break;
 
         /* Font name */
         case 'F':
             tag.persistent = MICRODVD_PERSISTENT_ON;
         case 'f': {
             int len = indexof(s, '}');
             if (len < 0)
                 break;
             tag.data_string = s;
             tag.data_string_len = len;
             s += len;
             tag.key = 'f';
             break;
         }
 
         /* Font size */
         case 'S':
             tag.persistent = MICRODVD_PERSISTENT_ON;
         case 's':
             tag.data1 = strtol(s, &s, 10);
             if (*s != '}')
                 break;
             tag.key = 's';
             break;
 
         /* Charset */
         case 'H': {
             //TODO: not yet handled, just parsed.
             int len = indexof(s, '}');
             if (len < 0)
                 break;
             tag.data_string = s;
             tag.data_string_len = len;
             s += len;
             tag.key = 'h';
             break;
         }
 
         /* Position */
         case 'P':
             tag.persistent = MICRODVD_PERSISTENT_ON;
             tag.data1 = (*s++ == '1');
             if (*s != '}')
                 break;
             tag.key = 'p';
             break;
 
         /* Coordinates */
         case 'o':
             tag.persistent = MICRODVD_PERSISTENT_ON;
             tag.data1 = strtol(s, &s, 10);
             if (*s != ',')
                 break;
             s++;
             tag.data2 = strtol(s, &s, 10);
             if (*s != '}')
                 break;
             tag.key = 'o';
             break;
 
         default:    /* Unknown tag, we consider it's text */
             break;
         }
 
         if (tag.key == 0)
             return start;
 
         microdvd_set_tag(tags, tag);
         s++;
     }
     return s;
 }
 
 static void microdvd_open_tags(AVBPrint *new_line, struct microdvd_tag *tags)
 {
     int i, sidx;
     for (i = 0; i < sizeof(MICRODVD_TAGS) - 1; i++) {
         if (tags[i].persistent == MICRODVD_PERSISTENT_OPENED)
             continue;
         switch (tags[i].key) {
         case 'Y':
         case 'y':
             for (sidx = 0; sidx < sizeof(MICRODVD_STYLES) - 1; sidx++)
                 if (tags[i].data1 & (1 << sidx))
                     av_bprintf(new_line, "{\\%c1}", MICRODVD_STYLES[sidx]);
             break;
 
         case 'c':
             av_bprintf(new_line, "{\\c&H%06X&}", tags[i].data1);
             break;
 
         case 'f':
             av_bprintf(new_line, "{\\fn%.*s}",
                        tags[i].data_string_len, tags[i].data_string);
             break;
 
         case 's':
             av_bprintf(new_line, "{\\fs%d}", tags[i].data1);
             break;
 
         case 'p':
             if (tags[i].data1 == 0)
                 av_bprintf(new_line, "{\\an8}");
             break;
 
         case 'o':
             av_bprintf(new_line, "{\\pos(%d,%d)}",
                        tags[i].data1, tags[i].data2);
             break;
         }
         if (tags[i].persistent == MICRODVD_PERSISTENT_ON)
             tags[i].persistent = MICRODVD_PERSISTENT_OPENED;
     }
 }
 
 static void microdvd_close_no_persistent_tags(AVBPrint *new_line,
                                               struct microdvd_tag *tags)
 {
     int i, sidx;
 

     for (i = sizeof(MICRODVD_TAGS) - 2; i >= 0; i--) {

         if (tags[i].persistent != MICRODVD_PERSISTENT_OFF)
             continue;
         switch (tags[i].key) {
 
         case 'y':
             for (sidx = sizeof(MICRODVD_STYLES) - 2; sidx >= 0; sidx--)
                 if (tags[i].data1 & (1 << sidx))
                     av_bprintf(new_line, "{\\%c0}", MICRODVD_STYLES[sidx]);
             break;
 
         case 'c':
             av_bprintf(new_line, "{\\c}");
             break;
 
         case 'f':
             av_bprintf(new_line, "{\\fn}");
             break;
 
         case 's':
             av_bprintf(new_line, "{\\fs}");
             break;
         }
         tags[i].key = 0;
     }
 }
 
 static int microdvd_decode_frame(AVCodecContext *avctx,
                                  void *data, int *got_sub_ptr, AVPacket *avpkt)
 {
     AVSubtitle *sub = data;
     AVBPrint new_line;

     char c;

     char *decoded_sub;
     char *line = avpkt->data;
     char *end = avpkt->data + avpkt->size;
     struct microdvd_tag tags[sizeof(MICRODVD_TAGS) - 1] = {{0}};
 
     if (avpkt->size <= 0)
         return avpkt->size;
 

     /* To be removed later */
     if (sscanf(line, "{%*d}{%*[0123456789]}%c", &c) == 1 &&
         line[avpkt->size - 1] == '\n') {
         av_log(avctx, AV_LOG_ERROR, "AVPacket is not clean (contains timing "
                "information and a trailing line break). You need to upgrade "
                "your libavformat or sanitize your packet.\n");
         return AVERROR_INVALIDDATA;
     }

     av_bprint_init(&new_line, 0, 2048);

 
     // subtitle content
     while (line < end && *line) {
 
         // parse MicroDVD tags, and open them in ASS
         line = microdvd_load_tags(tags, line);
         microdvd_open_tags(&new_line, tags);
 
         // simple copy until EOL or forced carriage return
         while (line < end && *line && *line != '|') {
             av_bprint_chars(&new_line, *line, 1);
             line++;
         }
 
         // line split
         if (line < end && *line == '|') {
             microdvd_close_no_persistent_tags(&new_line, tags);
             av_bprintf(&new_line, "\\N");
             line++;
         }
     }

     if (new_line.len) {
         av_bprintf(&new_line, "\r\n");

 
     av_bprint_finalize(&new_line, &decoded_sub);

     if (*decoded_sub) {
         int64_t start    = avpkt->pts;
         int64_t duration = avpkt->duration;
         int ts_start     = av_rescale_q(start,    avctx->time_base, (AVRational){1,100});
         int ts_duration  = duration != -1 ?
                            av_rescale_q(duration, avctx->time_base, (AVRational){1,100}) : -1;
         ff_ass_add_rect(sub, decoded_sub, ts_start, ts_duration, 0);
     }

     av_free(decoded_sub);

     }

 
     *got_sub_ptr = sub->num_rects > 0;
     return avpkt->size;
 }
 

 static int microdvd_init(AVCodecContext *avctx)
 {
     int i, sidx;
     AVBPrint font_buf;
     int font_size    = ASS_DEFAULT_FONT_SIZE;
     int color        = ASS_DEFAULT_COLOR;
     int bold         = ASS_DEFAULT_BOLD;
     int italic       = ASS_DEFAULT_ITALIC;
     int underline    = ASS_DEFAULT_UNDERLINE;
     int alignment    = ASS_DEFAULT_ALIGNMENT;
     struct microdvd_tag tags[sizeof(MICRODVD_TAGS) - 1] = {{0}};
 
     av_bprint_init(&font_buf, 0, AV_BPRINT_SIZE_AUTOMATIC);
     av_bprintf(&font_buf, "%s", ASS_DEFAULT_FONT);
 
     if (avctx->extradata) {
         microdvd_load_tags(tags, avctx->extradata);
         for (i = 0; i < sizeof(MICRODVD_TAGS) - 1; i++) {
             switch (av_tolower(tags[i].key)) {
             case 'y':
                 for (sidx = 0; sidx < sizeof(MICRODVD_STYLES) - 1; sidx++) {
                     if (tags[i].data1 & (1 << sidx)) {
                         switch (MICRODVD_STYLES[sidx]) {
                         case 'i': italic    = 1; break;
                         case 'b': bold      = 1; break;
                         case 'u': underline = 1; break;
                         }
                     }
                 }
                 break;
 
             case 'c': color     = tags[i].data1; break;
             case 's': font_size = tags[i].data1; break;
             case 'p': alignment =             8; break;
 
             case 'f':
                 av_bprint_clear(&font_buf);
                 av_bprintf(&font_buf, "%.*s",
                            tags[i].data_string_len, tags[i].data_string);
                 break;
             }
         }
     }
     return ff_ass_subtitle_header(avctx, font_buf.str, font_size, color,
                                   ASS_DEFAULT_BACK_COLOR, bold, italic,
                                   underline, alignment);
 }
 

 AVCodec ff_microdvd_decoder = {
     .name         = "microdvd",
     .long_name    = NULL_IF_CONFIG_SMALL("MicroDVD subtitle"),
     .type         = AVMEDIA_TYPE_SUBTITLE,

     .id           = AV_CODEC_ID_MICRODVD,

     .init         = microdvd_init,

     .decode       = microdvd_decode_frame,
 };