/*
  * 3GPP TS 26.245 Timed Text decoder
  * Copyright (c) 2012  Philip Langdale <philipl@overt.org>
  *
  * 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 "avcodec.h"
 #include "ass.h"
 #include "libavutil/avstring.h"
 #include "libavutil/common.h"
 #include "libavutil/bprint.h"
 #include "libavutil/intreadwrite.h"

 #include "libavutil/mem.h"

 #define STYLE_FLAG_BOLD         (1<<0)
 #define STYLE_FLAG_ITALIC       (1<<1)
 #define STYLE_FLAG_UNDERLINE    (1<<2)
 

 #define BOX_SIZE_INITIAL    40
 

 #define STYL_BOX   (1<<0)
 #define HLIT_BOX   (1<<1)
 #define HCLR_BOX   (1<<2)

 #define TWRP_BOX   (1<<3)

 #define BOTTOM_LEFT     1
 #define BOTTOM_CENTER   2
 #define BOTTOM_RIGHT    3
 #define MIDDLE_LEFT     4
 #define MIDDLE_CENTER   5
 #define MIDDLE_RIGHT    6
 #define TOP_LEFT        7
 #define TOP_CENTER      8
 #define TOP_RIGHT       9
 
 typedef struct {
     char *font;
     int fontsize;
     int color;
     int back_color;
     int bold;
     int italic;
     int underline;
     int alignment;
 } MovTextDefault;
 

 typedef struct {

     uint16_t fontID;
     char *font;
 } FontRecord;
 
 typedef struct {

     uint16_t style_start;
     uint16_t style_end;
     uint8_t style_flag;

     uint8_t fontsize;

     uint16_t style_fontID;

 } StyleBox;

 typedef struct {
     uint16_t hlit_start;
     uint16_t hlit_end;
 } HighlightBox;
 
 typedef struct {
    uint8_t hlit_color[4];
 } HilightcolorBox;
 
 typedef struct {

     uint8_t wrap_flag;
 } TextWrapBox;
 
 typedef struct {

     StyleBox **s;
     StyleBox *s_temp;
     HighlightBox h;
     HilightcolorBox c;

     FontRecord **ftab;
     FontRecord *ftab_temp;

     TextWrapBox w;

     MovTextDefault d;

     uint8_t box_flags;

     uint16_t style_entries, ftab_entries;

     uint64_t tracksize;
     int size_var;

     int count_s, count_f;

 } MovTextContext;
 
 typedef struct {
     uint32_t type;
     size_t base_size;
     int (*decode)(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt);
 } Box;
 
 static void mov_text_cleanup(MovTextContext *m)
 {
     int i;
     if (m->box_flags & STYL_BOX) {
         for(i = 0; i < m->count_s; i++) {
             av_freep(&m->s[i]);
         }
         av_freep(&m->s);
     }
 }
 

 static void mov_text_cleanup_ftab(MovTextContext *m)
 {
     int i;

     if (m->ftab_temp)
         av_freep(&m->ftab_temp->font);
     av_freep(&m->ftab_temp);

     if (m->ftab) {
         for(i = 0; i < m->count_f; i++) {
             av_freep(&m->ftab[i]->font);
             av_freep(&m->ftab[i]);
         }

     }
     av_freep(&m->ftab);
 }
 
 static int mov_text_tx3g(AVCodecContext *avctx, MovTextContext *m)
 {

     uint8_t *tx3g_ptr = avctx->extradata;

     int i, box_size, font_length;

     int8_t v_align, h_align;
     int style_fontID;
     StyleBox s_default;

     m->count_f = 0;

     m->ftab_entries = 0;
     box_size = BOX_SIZE_INITIAL; /* Size till ftab_entries */
     if (avctx->extradata_size < box_size)
         return -1;
 
     // Display Flags
     tx3g_ptr += 4;
     // Alignment

     h_align = *tx3g_ptr++;
     v_align = *tx3g_ptr++;
     if (h_align == 0) {
         if (v_align == 0)
             m->d.alignment = TOP_LEFT;
         if (v_align == 1)
             m->d.alignment = MIDDLE_LEFT;
         if (v_align == -1)
             m->d.alignment = BOTTOM_LEFT;
     }
     if (h_align == 1) {
         if (v_align == 0)
             m->d.alignment = TOP_CENTER;
         if (v_align == 1)
             m->d.alignment = MIDDLE_CENTER;
         if (v_align == -1)
             m->d.alignment = BOTTOM_CENTER;
     }
     if (h_align == -1) {
         if (v_align == 0)
             m->d.alignment = TOP_RIGHT;
         if (v_align == 1)
             m->d.alignment = MIDDLE_RIGHT;
         if (v_align == -1)
             m->d.alignment = BOTTOM_RIGHT;
     }

     // Background Color

     m->d.back_color = AV_RB24(tx3g_ptr);

     tx3g_ptr += 4;
     // BoxRecord
     tx3g_ptr += 8;
     // StyleRecord

     tx3g_ptr += 4;
     // fontID
     style_fontID = AV_RB16(tx3g_ptr);
     tx3g_ptr += 2;
     // face-style-flags
     s_default.style_flag = *tx3g_ptr++;
     m->d.bold = s_default.style_flag & STYLE_FLAG_BOLD;
     m->d.italic = s_default.style_flag & STYLE_FLAG_ITALIC;
     m->d.underline = s_default.style_flag & STYLE_FLAG_UNDERLINE;
     // fontsize
     m->d.fontsize = *tx3g_ptr++;
     // Primary color
     m->d.color = AV_RB24(tx3g_ptr);
     tx3g_ptr += 4;

     // FontRecord
     // FontRecord Size
     tx3g_ptr += 4;
     // ftab
     tx3g_ptr += 4;
 
     m->ftab_entries = AV_RB16(tx3g_ptr);
     tx3g_ptr += 2;
 
     for (i = 0; i < m->ftab_entries; i++) {
 
         box_size += 3;
         if (avctx->extradata_size < box_size) {
             mov_text_cleanup_ftab(m);
             m->ftab_entries = 0;
             return -1;
         }

         m->ftab_temp = av_mallocz(sizeof(*m->ftab_temp));

         if (!m->ftab_temp) {
             mov_text_cleanup_ftab(m);
             return AVERROR(ENOMEM);
         }
         m->ftab_temp->fontID = AV_RB16(tx3g_ptr);
         tx3g_ptr += 2;
         font_length = *tx3g_ptr++;
 
         box_size = box_size + font_length;
         if (avctx->extradata_size < box_size) {
             mov_text_cleanup_ftab(m);
             m->ftab_entries = 0;
             return -1;
         }
         m->ftab_temp->font = av_malloc(font_length + 1);
         if (!m->ftab_temp->font) {
             mov_text_cleanup_ftab(m);
             return AVERROR(ENOMEM);
         }
         memcpy(m->ftab_temp->font, tx3g_ptr, font_length);
         m->ftab_temp->font[font_length] = '\0';
         av_dynarray_add(&m->ftab, &m->count_f, m->ftab_temp);
         if (!m->ftab) {
             mov_text_cleanup_ftab(m);
             return AVERROR(ENOMEM);
         }

         m->ftab_temp = NULL;

         tx3g_ptr = tx3g_ptr + font_length;
     }

     for (i = 0; i < m->ftab_entries; i++) {
         if (style_fontID == m->ftab[i]->fontID)
             m->d.font = m->ftab[i]->font;
     }

     return 0;
 }
 

 static int decode_twrp(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
 {
     m->box_flags |= TWRP_BOX;
     m->w.wrap_flag = *tsmb++;
     return 0;
 }
 

 static int decode_hlit(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
 {
     m->box_flags |= HLIT_BOX;
     m->h.hlit_start = AV_RB16(tsmb);
     tsmb += 2;
     m->h.hlit_end = AV_RB16(tsmb);
     tsmb += 2;
     return 0;
 }
 
 static int decode_hclr(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
 {
     m->box_flags |= HCLR_BOX;
     memcpy(m->c.hlit_color, tsmb, 4);
     tsmb += 4;
     return 0;
 }
 
 static int decode_styl(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
 {
     int i;
     m->style_entries = AV_RB16(tsmb);
     tsmb += 2;
     // A single style record is of length 12 bytes.
     if (m->tracksize + m->size_var + 2 + m->style_entries * 12 > avpkt->size)
         return -1;
 
     m->box_flags |= STYL_BOX;
     for(i = 0; i < m->style_entries; i++) {
         m->s_temp = av_malloc(sizeof(*m->s_temp));
         if (!m->s_temp) {
             mov_text_cleanup(m);
             return AVERROR(ENOMEM);
         }
         m->s_temp->style_start = AV_RB16(tsmb);
         tsmb += 2;
         m->s_temp->style_end = AV_RB16(tsmb);
         tsmb += 2;

         m->s_temp->style_fontID = AV_RB16(tsmb);

         tsmb += 2;
         m->s_temp->style_flag = AV_RB8(tsmb);

         tsmb++;
         m->s_temp->fontsize = AV_RB8(tsmb);

         av_dynarray_add(&m->s, &m->count_s, m->s_temp);
         if(!m->s) {
             mov_text_cleanup(m);
             return AVERROR(ENOMEM);
         }

         tsmb++;

         // text-color-rgba
         tsmb += 4;
     }
     return 0;
 }
 
 static const Box box_types[] = {
     { MKBETAG('s','t','y','l'), 2, decode_styl },
     { MKBETAG('h','l','i','t'), 4, decode_hlit },

     { MKBETAG('h','c','l','r'), 4, decode_hclr },
     { MKBETAG('t','w','r','p'), 1, decode_twrp }

 };
 
 const static size_t box_count = FF_ARRAY_ELEMS(box_types);
 

 static int text_to_ass(AVBPrint *buf, const char *text, const char *text_end,

                         MovTextContext *m)

 {

     int i = 0;

     int j = 0;

     int text_pos = 0;

 
     if (text < text_end && m->box_flags & TWRP_BOX) {
         if (m->w.wrap_flag == 1) {
             av_bprintf(buf, "{\\q1}"); /* End of line wrap */
         } else {
             av_bprintf(buf, "{\\q2}"); /* No wrap */
         }
     }
 

     while (text < text_end) {

         if (m->box_flags & STYL_BOX) {
             for (i = 0; i < m->style_entries; i++) {
                 if (m->s[i]->style_flag && text_pos == m->s[i]->style_end) {

                     av_bprintf(buf, "{\\r}");

                 }
             }
             for (i = 0; i < m->style_entries; i++) {
                 if (m->s[i]->style_flag && text_pos == m->s[i]->style_start) {
                     if (m->s[i]->style_flag & STYLE_FLAG_BOLD)
                         av_bprintf(buf, "{\\b1}");
                     if (m->s[i]->style_flag & STYLE_FLAG_ITALIC)
                         av_bprintf(buf, "{\\i1}");
                     if (m->s[i]->style_flag & STYLE_FLAG_UNDERLINE)
                         av_bprintf(buf, "{\\u1}");

                     av_bprintf(buf, "{\\fs%d}", m->s[i]->fontsize);

                     for (j = 0; j < m->ftab_entries; j++) {
                         if (m->s[i]->style_fontID == m->ftab[j]->fontID)
                             av_bprintf(buf, "{\\fn%s}", m->ftab[j]->font);
                     }

                 }

             }
         }

         if (m->box_flags & HLIT_BOX) {
             if (text_pos == m->h.hlit_start) {
                 /* If hclr box is present, set the secondary color to the color
                  * specified. Otherwise, set primary color to white and secondary
                  * color to black. These colors will come from TextSampleModifier
                  * boxes in future and inverse video technique for highlight will
                  * be implemented.
                  */
                 if (m->box_flags & HCLR_BOX) {
                     av_bprintf(buf, "{\\2c&H%02x%02x%02x&}", m->c.hlit_color[2],
                                 m->c.hlit_color[1], m->c.hlit_color[0]);
                 } else {

                     av_bprintf(buf, "{\\1c&H000000&}{\\2c&HFFFFFF&}");

                 }
             }
             if (text_pos == m->h.hlit_end) {
                 if (m->box_flags & HCLR_BOX) {

                     av_bprintf(buf, "{\\2c&H000000&}");

                 } else {

                     av_bprintf(buf, "{\\1c&HFFFFFF&}{\\2c&H000000&}");

                 }

             }
         }
 

         switch (*text) {
         case '\r':
             break;
         case '\n':
             av_bprintf(buf, "\\N");
             break;
         default:
             av_bprint_chars(buf, *text, 1);
             break;
         }
         text++;

         text_pos++;

     }
 
     return 0;
 }
 
 static int mov_text_init(AVCodecContext *avctx) {
     /*
      * TODO: Handle the default text style.
      * NB: Most players ignore styles completely, with the result that
      * it's very common to find files where the default style is broken
      * and respecting it results in a worse experience than ignoring it.
      */

     int ret;

     MovTextContext *m = avctx->priv_data;

     ret = mov_text_tx3g(avctx, m);
     if (ret == 0) {
         return ff_ass_subtitle_header(avctx, m->d.font, m->d.fontsize, m->d.color,
                                 m->d.back_color, m->d.bold, m->d.italic,
                                 m->d.underline, m->d.alignment);
     } else
         return ff_ass_subtitle_header_default(avctx);

 }
 
 static int mov_text_decode_frame(AVCodecContext *avctx,
                             void *data, int *got_sub_ptr, AVPacket *avpkt)
 {
     AVSubtitle *sub = data;

     MovTextContext *m = avctx->priv_data;

     int ret, ts_start, ts_end;

     AVBPrint buf;

     char *ptr = avpkt->data;
     char *end;

     int text_length, tsmb_type, ret_tsmb;
     uint64_t tsmb_size;

     const uint8_t *tsmb;

     if (!ptr || avpkt->size < 2)
         return AVERROR_INVALIDDATA;
 
     /*
      * A packet of size two with value zero is an empty subtitle
      * used to mark the end of the previous non-empty subtitle.
      * We can just drop them here as we have duration information
      * already. If the value is non-zero, then it's technically a
      * bad packet.
      */
     if (avpkt->size == 2)
         return AV_RB16(ptr) == 0 ? 0 : AVERROR_INVALIDDATA;

 
     /*
      * The first two bytes of the packet are the length of the text string
      * In complex cases, there are style descriptors appended to the string
      * so we can't just assume the packet size is the string size.
      */

     text_length = AV_RB16(ptr);
     end = ptr + FFMIN(2 + text_length, avpkt->size);

     ptr += 2;
 
     ts_start = av_rescale_q(avpkt->pts,
                             avctx->time_base,
                             (AVRational){1,100});
     ts_end   = av_rescale_q(avpkt->pts + avpkt->duration,
                             avctx->time_base,
                             (AVRational){1,100});
 

     tsmb_size = 0;

     m->tracksize = 2 + text_length;
     m->style_entries = 0;
     m->box_flags = 0;
     m->count_s = 0;

     // Note that the spec recommends lines be no longer than 2048 characters.
     av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);

     if (text_length + 2 != avpkt->size) {

         while (m->tracksize + 8 <= avpkt->size) {

             // A box is a minimum of 8 bytes.

             tsmb = ptr + m->tracksize - 2;

             tsmb_size = AV_RB32(tsmb);
             tsmb += 4;
             tsmb_type = AV_RB32(tsmb);
             tsmb += 4;
 

             if (tsmb_size == 1) {

                 if (m->tracksize + 16 > avpkt->size)

                     break;
                 tsmb_size = AV_RB64(tsmb);
                 tsmb += 8;

                 m->size_var = 16;

             } else

                 m->size_var = 8;
             //size_var is equal to 8 or 16 depending on the size of box

             if (m->tracksize + tsmb_size > avpkt->size)

                 break;
 

             for (size_t i = 0; i < box_count; i++) {
                 if (tsmb_type == box_types[i].type) {
                     if (m->tracksize + m->size_var + box_types[i].base_size > avpkt->size)
                         break;
                     ret_tsmb = box_types[i].decode(tsmb, m, avpkt);
                     if (ret_tsmb == -1)
                         break;

                 }

             }

             m->tracksize = m->tracksize + tsmb_size;

         }

         text_to_ass(&buf, ptr, end, m);
         mov_text_cleanup(m);

     } else

         text_to_ass(&buf, ptr, end, m);

 
     ret = ff_ass_add_rect_bprint(sub, &buf, ts_start, ts_end - ts_start);

     av_bprint_finalize(&buf, NULL);

     if (ret < 0)
         return ret;
     *got_sub_ptr = sub->num_rects > 0;

     return avpkt->size;
 }
 

 static int mov_text_decode_close(AVCodecContext *avctx)
 {
     MovTextContext *m = avctx->priv_data;
     mov_text_cleanup_ftab(m);
     return 0;
 }
 

 AVCodec ff_movtext_decoder = {
     .name         = "mov_text",
     .long_name    = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"),
     .type         = AVMEDIA_TYPE_SUBTITLE,

     .id           = AV_CODEC_ID_MOV_TEXT,

     .priv_data_size = sizeof(MovTextContext),

     .init         = mov_text_init,
     .decode       = mov_text_decode_frame,

     .close        = mov_text_decode_close,

 };