/*
  * ID3v2 header writer
  *

  * 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 <stdint.h>

 #include <string.h>

 #include "libavutil/avstring.h"

 #include "libavutil/dict.h"
 #include "libavutil/intreadwrite.h"
 #include "avformat.h"
 #include "avio.h"

 #include "avio_internal.h"

 #include "id3v2.h"
 

 static void id3v2_put_size(AVIOContext *pb, int size)

 {

     avio_w8(pb, size >> 21 & 0x7f);
     avio_w8(pb, size >> 14 & 0x7f);
     avio_w8(pb, size >> 7  & 0x7f);
     avio_w8(pb, size       & 0x7f);

 }
 
 static int string_is_ascii(const uint8_t *str)
 {
     while (*str && *str < 128) str++;
     return !*str;
 }
 

 static void id3v2_encode_string(AVIOContext *pb, const uint8_t *str,
                                enum ID3v2Encoding enc)
 {
     int (*put)(AVIOContext*, const char*);
 
     if (enc == ID3v2_ENCODING_UTF16BOM) {
         avio_wl16(pb, 0xFEFF);      /* BOM */
         put = avio_put_str16le;
     } else
         put = avio_put_str;
 
     put(pb, str);
 }
 

 /**
  * Write a text frame with one (normal frames) or two (TXXX frames) strings
  * according to encoding (only UTF-8 or UTF-16+BOM supported).
  * @return number of bytes written or a negative error code.
  */

 static int id3v2_put_ttag(ID3v2EncContext *id3, AVIOContext *avioc, const char *str1, const char *str2,

                           uint32_t tag, enum ID3v2Encoding enc)
 {

     int len, ret;

     uint8_t *pb;
     AVIOContext *dyn_buf;

     if ((ret = avio_open_dyn_buf(&dyn_buf)) < 0)
         return ret;

 
     /* check if the strings are ASCII-only and use UTF16 only if
      * they're not */
     if (enc == ID3v2_ENCODING_UTF16BOM && string_is_ascii(str1) &&
         (!str2 || string_is_ascii(str2)))
         enc = ID3v2_ENCODING_ISO8859;
 
     avio_w8(dyn_buf, enc);

     id3v2_encode_string(dyn_buf, str1, enc);

     if (str2)

         id3v2_encode_string(dyn_buf, str2, enc);

     len = avio_get_dyn_buf(dyn_buf, &pb);

     avio_wb32(avioc, tag);

     /* ID3v2.3 frame size is not sync-safe */

     if (id3->version == 3)
         avio_wb32(avioc, len);
     else
         id3v2_put_size(avioc, len);
     avio_wb16(avioc, 0);
     avio_write(avioc, pb, len);

     ffio_free_dyn_buf(&dyn_buf);

     return len + ID3v2_HEADER_SIZE;
 }
 

 /**
  * Write a priv frame with owner and data. 'key' is the owner prepended with
  * ID3v2_PRIV_METADATA_PREFIX. 'data' is provided as a string. Any \xXX
  * (where 'X' is a valid hex digit) will be unescaped to the byte value.
  */
 static int id3v2_put_priv(ID3v2EncContext *id3, AVIOContext *avioc, const char *key, const char *data)
 {

     int len, ret;

     uint8_t *pb;
     AVIOContext *dyn_buf;
 
     if (!av_strstart(key, ID3v2_PRIV_METADATA_PREFIX, &key)) {
         return 0;
     }
 

     if ((ret = avio_open_dyn_buf(&dyn_buf)) < 0)
         return ret;

 
     // owner + null byte.
     avio_write(dyn_buf, key, strlen(key) + 1);
 
     while (*data) {
         if (av_strstart(data, "\\x", &data)) {
             if (data[0] && data[1] && av_isxdigit(data[0]) && av_isxdigit(data[1])) {
                 char digits[] = {data[0], data[1], 0};
                 avio_w8(dyn_buf, strtol(digits, NULL, 16));
                 data += 2;
             } else {
                 ffio_free_dyn_buf(&dyn_buf);
                 av_log(avioc, AV_LOG_ERROR, "Invalid escape '\\x%.2s' in metadata tag '"
                        ID3v2_PRIV_METADATA_PREFIX "%s'.\n", data, key);
                 return AVERROR(EINVAL);
             }
         } else {
             avio_write(dyn_buf, data++, 1);
         }
     }
 

     len = avio_get_dyn_buf(dyn_buf, &pb);

 
     avio_wb32(avioc, MKBETAG('P', 'R', 'I', 'V'));
     if (id3->version == 3)
         avio_wb32(avioc, len);
     else
         id3v2_put_size(avioc, len);
     avio_wb16(avioc, 0);
     avio_write(avioc, pb, len);
 

     ffio_free_dyn_buf(&dyn_buf);

 
     return len + ID3v2_HEADER_SIZE;
 }
 

 static int id3v2_check_write_tag(ID3v2EncContext *id3, AVIOContext *pb, AVDictionaryEntry *t,
                                  const char table[][4], enum ID3v2Encoding enc)

 {
     uint32_t tag;
     int i;
 
     if (t->key[0] != 'T' || strlen(t->key) != 4)
         return -1;
     tag = AV_RB32(t->key);
     for (i = 0; *table[i]; i++)
         if (tag == AV_RB32(table[i]))

             return id3v2_put_ttag(id3, pb, t->value, NULL, tag, enc);

     return -1;
 }
 

 static void id3v2_3_metadata_split_date(AVDictionary **pm)
 {
     AVDictionaryEntry *mtag = NULL;
     AVDictionary *dst = NULL;
     const char *key, *value;
     char year[5] = {0}, day_month[5] = {0};
     int i;
 
     while ((mtag = av_dict_get(*pm, "", mtag, AV_DICT_IGNORE_SUFFIX))) {
         key = mtag->key;

         if (!av_strcasecmp(key, "date")) {

             /* split date tag using "YYYY-MM-DD" format into year and month/day segments */
             value = mtag->value;
             i = 0;
             while (value[i] >= '0' && value[i] <= '9') i++;
             if (value[i] == '\0' || value[i] == '-') {
                 av_strlcpy(year, value, sizeof(year));
                 av_dict_set(&dst, "TYER", year, 0);
 
                 if (value[i] == '-' &&
                     value[i+1] >= '0' && value[i+1] <= '1' &&
                     value[i+2] >= '0' && value[i+2] <= '9' &&
                     value[i+3] == '-' &&
                     value[i+4] >= '0' && value[i+4] <= '3' &&
                     value[i+5] >= '0' && value[i+5] <= '9' &&
                     (value[i+6] == '\0' || value[i+6] == ' ')) {
                     snprintf(day_month, sizeof(day_month), "%.2s%.2s", value + i + 4, value + i + 1);
                     av_dict_set(&dst, "TDAT", day_month, 0);
                 }
             } else
                 av_dict_set(&dst, key, value, 0);
         } else
             av_dict_set(&dst, key, mtag->value, 0);
     }
     av_dict_free(pm);
     *pm = dst;
 }
 

 void ff_id3v2_start(ID3v2EncContext *id3, AVIOContext *pb, int id3v2_version,
                     const char *magic)

 {

     id3->version = id3v2_version;

     avio_wb32(pb, MKBETAG(magic[0], magic[1], magic[2], id3v2_version));
     avio_w8(pb, 0);
     avio_w8(pb, 0); /* flags */

 
     /* reserve space for size */

     id3->size_pos = avio_tell(pb);
     avio_wb32(pb, 0);
 }
 

 static int write_metadata(AVIOContext *pb, AVDictionary **metadata,
                           ID3v2EncContext *id3, int enc)

 {
     AVDictionaryEntry *t = NULL;

     int ret;

     ff_metadata_conv(metadata, ff_id3v2_34_metadata_conv, NULL);

     if (id3->version == 3)

         id3v2_3_metadata_split_date(metadata);

     else if (id3->version == 4)

         ff_metadata_conv(metadata, ff_id3v2_4_metadata_conv, NULL);

     while ((t = av_dict_get(*metadata, "", t, AV_DICT_IGNORE_SUFFIX))) {
         if ((ret = id3v2_check_write_tag(id3, pb, t, ff_id3v2_tags, enc)) > 0) {

             id3->len += ret;

             continue;
         }

         if ((ret = id3v2_check_write_tag(id3, pb, t, id3->version == 3 ?
                                          ff_id3v2_3_tags : ff_id3v2_4_tags, enc)) > 0) {

             id3->len += ret;

             continue;
         }
 

         if ((ret = id3v2_put_priv(id3, pb, t->key, t->value)) > 0) {
             id3->len += ret;
             continue;
         } else if (ret < 0) {
             return ret;
         }
 

         /* unknown tag, write as TXXX frame */

         if ((ret = id3v2_put_ttag(id3, pb, t->key, t->value, MKBETAG('T', 'X', 'X', 'X'), enc)) < 0)

             return ret;

         id3->len += ret;

     }
 

     return 0;
 }
 

 static int write_ctoc(AVFormatContext *s, ID3v2EncContext *id3, int enc)
 {

     uint8_t *dyn_buf;
     AVIOContext *dyn_bc;

     char name[123];
     int len, ret;
 
     if (s->nb_chapters == 0)
         return 0;
 
     if ((ret = avio_open_dyn_buf(&dyn_bc)) < 0)

         return ret;

     avio_put_str(dyn_bc, "toc");

     avio_w8(dyn_bc, 0x03);

     avio_w8(dyn_bc, s->nb_chapters);
     for (int i = 0; i < s->nb_chapters; i++) {
         snprintf(name, 122, "ch%d", i);

         avio_put_str(dyn_bc, name);

     }

     len = avio_get_dyn_buf(dyn_bc, &dyn_buf);

     id3->len += len + ID3v2_HEADER_SIZE;

 
     avio_wb32(s->pb, MKBETAG('C', 'T', 'O', 'C'));
     avio_wb32(s->pb, len);
     avio_wb16(s->pb, 0);
     avio_write(s->pb, dyn_buf, len);
 

     ffio_free_dyn_buf(&dyn_bc);

 
     return ret;
 }
 

 static int write_chapter(AVFormatContext *s, ID3v2EncContext *id3, int id, int enc)
 {
     const AVRational time_base = {1, 1000};
     AVChapter *ch = s->chapters[id];

     uint8_t *dyn_buf;
     AVIOContext *dyn_bc;

     char name[123];
     int len, start, end, ret;
 
     if ((ret = avio_open_dyn_buf(&dyn_bc)) < 0)

         return ret;

 
     start = av_rescale_q(ch->start, ch->time_base, time_base);
     end   = av_rescale_q(ch->end,   ch->time_base, time_base);
 
     snprintf(name, 122, "ch%d", id);
     id3->len += avio_put_str(dyn_bc, name);
     avio_wb32(dyn_bc, start);
     avio_wb32(dyn_bc, end);
     avio_wb32(dyn_bc, 0xFFFFFFFFu);
     avio_wb32(dyn_bc, 0xFFFFFFFFu);
 
     if ((ret = write_metadata(dyn_bc, &ch->metadata, id3, enc)) < 0)
         goto fail;
 

     len = avio_get_dyn_buf(dyn_bc, &dyn_buf);

     id3->len += 16 + ID3v2_HEADER_SIZE;
 
     avio_wb32(s->pb, MKBETAG('C', 'H', 'A', 'P'));
     avio_wb32(s->pb, len);
     avio_wb16(s->pb, 0);
     avio_write(s->pb, dyn_buf, len);
 
 fail:

     ffio_free_dyn_buf(&dyn_bc);

 
     return ret;
 }
 
 int ff_id3v2_write_metadata(AVFormatContext *s, ID3v2EncContext *id3)
 {
     int enc = id3->version == 3 ? ID3v2_ENCODING_UTF16BOM :
                                   ID3v2_ENCODING_UTF8;
     int i, ret;
 

     ff_standardize_creation_time(s);

     if ((ret = write_metadata(s->pb, &s->metadata, id3, enc)) < 0)
         return ret;
 

     if ((ret = write_ctoc(s, id3, enc)) < 0)
         return ret;
 

     for (i = 0; i < s->nb_chapters; i++) {
         if ((ret = write_chapter(s, id3, i, enc)) < 0)
             return ret;
     }
 
     return 0;
 }
 

 int ff_id3v2_write_apic(AVFormatContext *s, ID3v2EncContext *id3, AVPacket *pkt)
 {
     AVStream *st = s->streams[pkt->stream_index];
     AVDictionaryEntry *e;
 
     AVIOContext *dyn_buf;
     uint8_t     *buf;
     const CodecMime *mime = ff_id3v2_mime_tags;
     const char  *mimetype = NULL, *desc = "";
     int enc = id3->version == 3 ? ID3v2_ENCODING_UTF16BOM :
                                   ID3v2_ENCODING_UTF8;

     int i, len, type = 0, ret;

 
     /* get the mimetype*/

     while (mime->id != AV_CODEC_ID_NONE) {

         if (mime->id == st->codecpar->codec_id) {

             mimetype = mime->str;
             break;
         }
         mime++;
     }
     if (!mimetype) {
         av_log(s, AV_LOG_ERROR, "No mimetype is known for stream %d, cannot "
                "write an attached picture.\n", st->index);
         return AVERROR(EINVAL);
     }
 
     /* get the picture type */
     e = av_dict_get(st->metadata, "comment", NULL, 0);
     for (i = 0; e && i < FF_ARRAY_ELEMS(ff_id3v2_picture_types); i++) {

         if (!av_strcasecmp(e->value, ff_id3v2_picture_types[i])) {

             type = i;
             break;
         }
     }
 
     /* get the description */
     if ((e = av_dict_get(st->metadata, "title", NULL, 0)))
         desc = e->value;
 

     /* use UTF16 only for non-ASCII strings */
     if (enc == ID3v2_ENCODING_UTF16BOM && string_is_ascii(desc))
         enc = ID3v2_ENCODING_ISO8859;
 

     /* start writing */

     if ((ret = avio_open_dyn_buf(&dyn_buf)) < 0)
         return ret;

 
     avio_w8(dyn_buf, enc);
     avio_put_str(dyn_buf, mimetype);
     avio_w8(dyn_buf, type);
     id3v2_encode_string(dyn_buf, desc, enc);
     avio_write(dyn_buf, pkt->data, pkt->size);

     len = avio_get_dyn_buf(dyn_buf, &buf);

 
     avio_wb32(s->pb, MKBETAG('A', 'P', 'I', 'C'));
     if (id3->version == 3)
         avio_wb32(s->pb, len);
     else
         id3v2_put_size(s->pb, len);
     avio_wb16(s->pb, 0);
     avio_write(s->pb, buf, len);

     ffio_free_dyn_buf(&dyn_buf);

 
     id3->len += len + ID3v2_HEADER_SIZE;
 
     return 0;
 }
 

 void ff_id3v2_finish(ID3v2EncContext *id3, AVIOContext *pb,
                      int padding_bytes)

 {

     int64_t cur_pos;
 

     if (padding_bytes < 0)
         padding_bytes = 10;
 
     /* The ID3v2.3 specification states that 28 bits are used to represent the
      * size of the whole tag.  Therefore the current size of the tag needs to be
      * subtracted from the upper limit of 2^28-1 to clip the value correctly. */

     /* The minimum of 10 is an arbitrary amount of padding at the end of the tag
      * to fix cover art display with some software such as iTunes, Traktor,
      * Serato, Torq. */

     padding_bytes = av_clip(padding_bytes, 10, 268435455 - id3->len);
     ffio_fill(pb, 0, padding_bytes);
     id3->len += padding_bytes;

 
     cur_pos = avio_tell(pb);

     avio_seek(pb, id3->size_pos, SEEK_SET);
     id3v2_put_size(pb, id3->len);
     avio_seek(pb, cur_pos, SEEK_SET);
 }
 
 int ff_id3v2_write_simple(struct AVFormatContext *s, int id3v2_version,
                           const char *magic)
 {
     ID3v2EncContext id3 = { 0 };
     int ret;
 
     ff_id3v2_start(&id3, s->pb, id3v2_version, magic);
     if ((ret = ff_id3v2_write_metadata(s, &id3)) < 0)
         return ret;

     ff_id3v2_finish(&id3, s->pb, s->metadata_header_padding);

     return 0;
 }