/*
  * 3GPP TS 26.245 Timed Text encoder
  * 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 <stdarg.h>
 #include "avcodec.h"

 #include "libavutil/avassert.h"

 #include "libavutil/avstring.h"

 #include "libavutil/intreadwrite.h"

 #include "ass_split.h"
 #include "ass.h"
 
 typedef struct {
     ASSSplitContext *ass_ctx;
     char buffer[2048];
     char *ptr;
     char *end;
 } MovTextContext;
 
 
 static av_cold int mov_text_encode_init(AVCodecContext *avctx)
 {
     /*
      * For now, we'll use a fixed default style. When we add styling
      * support, this will be generated from the ASS style.
      */

     static const uint8_t text_sample_entry[] = {

         0x00, 0x00, 0x00, 0x00, // uint32_t displayFlags
         0x01,                   // int8_t horizontal-justification
         0xFF,                   // int8_t vertical-justification
         0x00, 0x00, 0x00, 0x00, // uint8_t background-color-rgba[4]
         // BoxRecord {
         0x00, 0x00,             // int16_t top
         0x00, 0x00,             // int16_t left
         0x00, 0x00,             // int16_t bottom
         0x00, 0x00,             // int16_t right
         // };
         // StyleRecord {
         0x00, 0x00,             // uint16_t startChar
         0x00, 0x00,             // uint16_t endChar
         0x00, 0x01,             // uint16_t font-ID
         0x00,                   // uint8_t face-style-flags
         0x12,                   // uint8_t font-size
         0xFF, 0xFF, 0xFF, 0xFF, // uint8_t text-color-rgba[4]
         // };
         // FontTableBox {
         0x00, 0x00, 0x00, 0x12, // uint32_t size
         'f', 't', 'a', 'b',     // uint8_t name[4]
         0x00, 0x01,             // uint16_t entry-count
         // FontRecord {
         0x00, 0x01,             // uint16_t font-ID
         0x05,                   // uint8_t font-name-length
         'S', 'e', 'r', 'i', 'f',// uint8_t font[font-name-length]
         // };
         // };
     };
 
     MovTextContext *s = avctx->priv_data;
 
     avctx->extradata_size = sizeof text_sample_entry;

     avctx->extradata = av_mallocz(avctx->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);

     if (!avctx->extradata)
         return AVERROR(ENOMEM);
 
     memcpy(avctx->extradata, text_sample_entry, avctx->extradata_size);
 
     s->ass_ctx = ff_ass_split(avctx->subtitle_header);
     return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;
 }
 
 static void mov_text_text_cb(void *priv, const char *text, int len)
 {
     MovTextContext *s = priv;

     av_assert0(s->end >= s->ptr);

     av_strlcpy(s->ptr, text, FFMIN(s->end - s->ptr, len + 1));

     s->ptr += FFMIN(s->end - s->ptr, len);

 }
 
 static void mov_text_new_line_cb(void *priv, int forced)
 {
     MovTextContext *s = priv;

     av_assert0(s->end >= s->ptr);

     av_strlcpy(s->ptr, "\n", FFMIN(s->end - s->ptr, 2));

     if (s->end > s->ptr)
         s->ptr++;

 }
 
 static const ASSCodesCallbacks mov_text_callbacks = {
     .text     = mov_text_text_cb,
     .new_line = mov_text_new_line_cb,
 };
 
 static int mov_text_encode_frame(AVCodecContext *avctx, unsigned char *buf,

                                  int bufsize, const AVSubtitle *sub)

 {
     MovTextContext *s = avctx->priv_data;
     ASSDialog *dialog;
     int i, len, num;
 
     s->ptr = s->buffer;
     s->end = s->ptr + sizeof(s->buffer);
 
     for (i = 0; i < sub->num_rects; i++) {
 
         if (sub->rects[i]->type != SUBTITLE_ASS) {
             av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
             return AVERROR(ENOSYS);
         }
 
         dialog = ff_ass_split_dialog(s->ass_ctx, sub->rects[i]->ass, 0, &num);
         for (; dialog && num--; dialog++) {
             ff_ass_split_override_codes(&mov_text_callbacks, s, dialog->text);
         }
     }
 
     if (s->ptr == s->buffer)
         return 0;
 
     AV_WB16(buf, strlen(s->buffer));
     buf += 2;
 
     len = av_strlcpy(buf, s->buffer, bufsize - 2);
 
     if (len > bufsize-3) {
         av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
         return AVERROR(EINVAL);
     }
 
     return len + 2;
 }
 
 static int mov_text_encode_close(AVCodecContext *avctx)
 {
     MovTextContext *s = avctx->priv_data;
     ff_ass_split_free(s->ass_ctx);
     return 0;
 }
 
 AVCodec ff_movtext_encoder = {
     .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_encode_init,

     .encode_sub     = mov_text_encode_frame,

     .close          = mov_text_encode_close,
 };