/*
  * SubRip subtitle encoder
  * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.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/avstring.h"

 #include "libavutil/bprint.h"

 #include "ass_split.h"
 #include "ass.h"
 
 
 #define SRT_STACK_SIZE 64
 
 typedef struct {
     AVCodecContext *avctx;
     ASSSplitContext *ass_ctx;

     AVBPrint buffer;

     char stack[SRT_STACK_SIZE];
     int stack_ptr;
     int alignment_applied;
 } SRTContext;
 
 
 #ifdef __GNUC__
 __attribute__ ((__format__ (__printf__, 2, 3)))
 #endif
 static void srt_print(SRTContext *s, const char *str, ...)
 {
     va_list vargs;
     va_start(vargs, str);

     av_vbprintf(&s->buffer, str, vargs);

     va_end(vargs);
 }
 
 static int srt_stack_push(SRTContext *s, const char c)
 {
     if (s->stack_ptr >= SRT_STACK_SIZE)
         return -1;
     s->stack[s->stack_ptr++] = c;
     return 0;
 }
 
 static char srt_stack_pop(SRTContext *s)
 {
     if (s->stack_ptr <= 0)
         return 0;
     return s->stack[--s->stack_ptr];
 }
 
 static int srt_stack_find(SRTContext *s, const char c)
 {
     int i;
     for (i = s->stack_ptr-1; i >= 0; i--)
         if (s->stack[i] == c)
             break;
     return i;
 }
 
 static void srt_close_tag(SRTContext *s, char tag)
 {
     srt_print(s, "</%c%s>", tag, tag == 'f' ? "ont" : "");
 }
 
 static void srt_stack_push_pop(SRTContext *s, const char c, int close)
 {
     if (close) {
         int i = c ? srt_stack_find(s, c) : 0;
         if (i < 0)
             return;
         while (s->stack_ptr != i)
             srt_close_tag(s, srt_stack_pop(s));
     } else if (srt_stack_push(s, c) < 0)
         av_log(s->avctx, AV_LOG_ERROR, "tag stack overflow\n");
 }
 
 static void srt_style_apply(SRTContext *s, const char *style)
 {

     ASSStyle *st = ff_ass_style_get(s->ass_ctx, style);

     if (st) {
         int c = st->primary_color & 0xFFFFFF;
         if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT) ||
             st->font_size != ASS_DEFAULT_FONT_SIZE ||
             c != ASS_DEFAULT_COLOR) {
             srt_print(s, "<font");
             if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT))
                 srt_print(s, " face=\"%s\"", st->font_name);
             if (st->font_size != ASS_DEFAULT_FONT_SIZE)
                 srt_print(s, " size=\"%d\"", st->font_size);
             if (c != ASS_DEFAULT_COLOR)
                 srt_print(s, " color=\"#%06x\"",
                           (c & 0xFF0000) >> 16 | c & 0xFF00 | (c & 0xFF) << 16);
             srt_print(s, ">");
             srt_stack_push(s, 'f');
         }
         if (st->bold != ASS_DEFAULT_BOLD) {
             srt_print(s, "<b>");
             srt_stack_push(s, 'b');
         }
         if (st->italic != ASS_DEFAULT_ITALIC) {
             srt_print(s, "<i>");
             srt_stack_push(s, 'i');
         }
         if (st->underline != ASS_DEFAULT_UNDERLINE) {
             srt_print(s, "<u>");
             srt_stack_push(s, 'u');
         }
         if (st->alignment != ASS_DEFAULT_ALIGNMENT) {
             srt_print(s, "{\\an%d}", st->alignment);
             s->alignment_applied = 1;
         }
     }
 }
 
 
 static av_cold int srt_encode_init(AVCodecContext *avctx)
 {
     SRTContext *s = avctx->priv_data;
     s->avctx = avctx;
     s->ass_ctx = ff_ass_split(avctx->subtitle_header);

     av_bprint_init(&s->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);

     return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;
 }
 
 static void srt_text_cb(void *priv, const char *text, int len)
 {
     SRTContext *s = priv;

     av_bprint_append_data(&s->buffer, text, len);

 }
 
 static void srt_new_line_cb(void *priv, int forced)
 {
     srt_print(priv, "\r\n");
 }
 
 static void srt_style_cb(void *priv, char style, int close)
 {
     srt_stack_push_pop(priv, style, close);
     if (!close)
         srt_print(priv, "<%c>", style);
 }
 
 static void srt_color_cb(void *priv, unsigned int color, unsigned int color_id)
 {
     if (color_id > 1)
         return;
     srt_stack_push_pop(priv, 'f', color == 0xFFFFFFFF);
     if (color != 0xFFFFFFFF)
         srt_print(priv, "<font color=\"#%06x\">",
               (color & 0xFF0000) >> 16 | color & 0xFF00 | (color & 0xFF) << 16);
 }
 
 static void srt_font_name_cb(void *priv, const char *name)
 {
     srt_stack_push_pop(priv, 'f', !name);
     if (name)
         srt_print(priv, "<font face=\"%s\">", name);
 }
 
 static void srt_font_size_cb(void *priv, int size)
 {
     srt_stack_push_pop(priv, 'f', size < 0);
     if (size >= 0)
         srt_print(priv, "<font size=\"%d\">", size);
 }
 
 static void srt_alignment_cb(void *priv, int alignment)
 {
     SRTContext *s = priv;
     if (!s->alignment_applied && alignment >= 0) {
         srt_print(s, "{\\an%d}", alignment);
         s->alignment_applied = 1;
     }
 }
 
 static void srt_cancel_overrides_cb(void *priv, const char *style)
 {
     srt_stack_push_pop(priv, 0, 1);
     srt_style_apply(priv, style);
 }
 
 static void srt_move_cb(void *priv, int x1, int y1, int x2, int y2,
                         int t1, int t2)
 {

     // TODO: add a AV_PKT_DATA_SUBTITLE_POSITION side data when a new subtitles
     // encoding API passing the AVPacket is available.

 }
 
 static void srt_end_cb(void *priv)
 {
     srt_stack_push_pop(priv, 0, 1);
 }
 
 static const ASSCodesCallbacks srt_callbacks = {
     .text             = srt_text_cb,
     .new_line         = srt_new_line_cb,
     .style            = srt_style_cb,
     .color            = srt_color_cb,
     .font_name        = srt_font_name_cb,
     .font_size        = srt_font_size_cb,
     .alignment        = srt_alignment_cb,
     .cancel_overrides = srt_cancel_overrides_cb,
     .move             = srt_move_cb,
     .end              = srt_end_cb,
 };
 
 static int srt_encode_frame(AVCodecContext *avctx,

                             unsigned char *buf, int bufsize, const AVSubtitle *sub)

 {
     SRTContext *s = avctx->priv_data;
     ASSDialog *dialog;

     int i, num;

     av_bprint_clear(&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++) {
             s->alignment_applied = 0;
             srt_style_apply(s, dialog->style);
             ff_ass_split_override_codes(&srt_callbacks, s, dialog->text);
         }
     }
 

     if (!av_bprint_is_complete(&s->buffer))
         return AVERROR(ENOMEM);
     if (!s->buffer.len)

         return 0;
 

     if (s->buffer.len > bufsize) {

         av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
         return -1;
     }

     memcpy(buf, s->buffer.str, s->buffer.len);

     return s->buffer.len;

 }
 
 static int srt_encode_close(AVCodecContext *avctx)
 {
     SRTContext *s = avctx->priv_data;
     ff_ass_split_free(s->ass_ctx);

     av_bprint_finalize(&s->buffer, NULL);

     return 0;
 }
 

 #if CONFIG_SRT_ENCODER

 /* deprecated encoder */

 AVCodec ff_srt_encoder = {
     .name           = "srt",

     .long_name      = NULL_IF_CONFIG_SMALL("SubRip subtitle"),

     .type           = AVMEDIA_TYPE_SUBTITLE,

     .id             = AV_CODEC_ID_SUBRIP,

     .priv_data_size = sizeof(SRTContext),
     .init           = srt_encode_init,

     .encode_sub     = srt_encode_frame,

     .close          = srt_encode_close,
 };

 #endif
 
 #if CONFIG_SUBRIP_ENCODER
 AVCodec ff_subrip_encoder = {
     .name           = "subrip",
     .long_name      = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
     .type           = AVMEDIA_TYPE_SUBTITLE,
     .id             = AV_CODEC_ID_SUBRIP,
     .priv_data_size = sizeof(SRTContext),
     .init           = srt_encode_init,

     .encode_sub     = srt_encode_frame,

     .close          = srt_encode_close,
 };
 #endif