/*
  * Copyright (c) 2011 Baptiste Coudurier
  * Copyright (c) 2011 Stefano Sabatini

  * 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
  * Libass subtitles burning filter.
  *
  * @see{http://www.matroska.org/technical/specs/subtitles/ssa.html}
  */
 
 #include <ass/ass.h>
 

 #include "config.h"
 #if CONFIG_SUBTITLES_FILTER
 # include "libavcodec/avcodec.h"
 # include "libavformat/avformat.h"
 #endif

 #include "libavutil/avstring.h"
 #include "libavutil/imgutils.h"

 #include "libavutil/opt.h"
 #include "libavutil/parseutils.h"

 #include "drawutils.h"
 #include "avfilter.h"

 #include "internal.h"

 #include "formats.h"
 #include "video.h"

 typedef struct AssContext {

     const AVClass *class;

     ASS_Library  *library;
     ASS_Renderer *renderer;
     ASS_Track    *track;
     char *filename;

     char *fontsdir;

     char *charenc;

     char *force_style;

     int stream_index;

     int alpha;

     uint8_t rgba_map[4];
     int     pix_step[4];       ///< steps per pixel for each plane of the main output

     int original_w, original_h;

     int shaping;

     FFDrawContext draw;

 } AssContext;
 

 #define OFFSET(x) offsetof(AssContext, x)

 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

 #define COMMON_OPTIONS \
     {"filename",       "set the filename of file to read",                         OFFSET(filename),   AV_OPT_TYPE_STRING,     {.str = NULL},  CHAR_MIN, CHAR_MAX, FLAGS }, \
     {"f",              "set the filename of file to read",                         OFFSET(filename),   AV_OPT_TYPE_STRING,     {.str = NULL},  CHAR_MIN, CHAR_MAX, FLAGS }, \
     {"original_size",  "set the size of the original video (used to scale fonts)", OFFSET(original_w), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL},  CHAR_MIN, CHAR_MAX, FLAGS }, \

     {"fontsdir",       "set the directory containing the fonts to read",           OFFSET(fontsdir),   AV_OPT_TYPE_STRING,     {.str = NULL},  CHAR_MIN, CHAR_MAX, FLAGS }, \

     {"alpha",          "enable processing of alpha channel",                       OFFSET(alpha),      AV_OPT_TYPE_BOOL,       {.i64 = 0   },         0,        1, FLAGS }, \

 /* libass supports a log level ranging from 0 to 7 */

 static const int ass_libavfilter_log_level_map[] = {

     [0] = AV_LOG_FATAL,     /* MSGL_FATAL */
     [1] = AV_LOG_ERROR,     /* MSGL_ERR */
     [2] = AV_LOG_WARNING,   /* MSGL_WARN */
     [3] = AV_LOG_WARNING,   /* <undefined> */
     [4] = AV_LOG_INFO,      /* MSGL_INFO */
     [5] = AV_LOG_INFO,      /* <undefined> */
     [6] = AV_LOG_VERBOSE,   /* MSGL_V */
     [7] = AV_LOG_DEBUG,     /* MSGL_DBG2 */

 };
 
 static void ass_log(int ass_level, const char *fmt, va_list args, void *ctx)
 {

     const int ass_level_clip = av_clip(ass_level, 0,
         FF_ARRAY_ELEMS(ass_libavfilter_log_level_map) - 1);
     const int level = ass_libavfilter_log_level_map[ass_level_clip];

 
     av_vlog(ctx, level, fmt, args);
     av_log(ctx, level, "\n");
 }
 

 static av_cold int init(AVFilterContext *ctx)

 {
     AssContext *ass = ctx->priv;

 
     if (!ass->filename) {

         av_log(ctx, AV_LOG_ERROR, "No filename provided!\n");
         return AVERROR(EINVAL);
     }
 
     ass->library = ass_library_init();
     if (!ass->library) {
         av_log(ctx, AV_LOG_ERROR, "Could not initialize libass.\n");
         return AVERROR(EINVAL);
     }
     ass_set_message_cb(ass->library, ass_log, ctx);
 

     ass_set_fonts_dir(ass->library, ass->fontsdir);
 

     ass->renderer = ass_renderer_init(ass->library);
     if (!ass->renderer) {
         av_log(ctx, AV_LOG_ERROR, "Could not initialize libass renderer.\n");
         return AVERROR(EINVAL);
     }
 
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     AssContext *ass = ctx->priv;
 
     if (ass->track)
         ass_free_track(ass->track);
     if (ass->renderer)
         ass_renderer_done(ass->renderer);
     if (ass->library)
         ass_library_done(ass->library);
 }
 
 static int query_formats(AVFilterContext *ctx)
 {

     return ff_set_common_formats(ctx, ff_draw_supported_pixel_formats(0));

 }
 
 static int config_input(AVFilterLink *inlink)
 {
     AssContext *ass = inlink->dst->priv;
 

     ff_draw_init(&ass->draw, inlink->format, ass->alpha ? FF_DRAW_PROCESS_ALPHA : 0);

 
     ass_set_frame_size  (ass->renderer, inlink->w, inlink->h);

     if (ass->original_w && ass->original_h)
         ass_set_aspect_ratio(ass->renderer, (double)inlink->w / inlink->h,
                              (double)ass->original_w / ass->original_h);

     if (ass->shaping != -1)
         ass_set_shaper(ass->renderer, ass->shaping);

 
     return 0;
 }
 
 /* libass stores an RGBA color in the format RRGGBBTT, where TT is the transparency level */
 #define AR(c)  ( (c)>>24)
 #define AG(c)  (((c)>>16)&0xFF)
 #define AB(c)  (((c)>>8) &0xFF)

 #define AA(c)  ((0xFF-(c)) &0xFF)

 static void overlay_ass_image(AssContext *ass, AVFrame *picref,

                               const ASS_Image *image)
 {
     for (; image; image = image->next) {
         uint8_t rgba_color[] = {AR(image->color), AG(image->color), AB(image->color), AA(image->color)};

         FFDrawColor color;
         ff_draw_color(&ass->draw, &color, rgba_color);
         ff_blend_mask(&ass->draw, &color,
                       picref->data, picref->linesize,

                       picref->width, picref->height,

                       image->bitmap, image->stride, image->w, image->h,
                       3, 0, image->dst_x, image->dst_y);

     }
 }
 

 static int filter_frame(AVFilterLink *inlink, AVFrame *picref)

 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     AssContext *ass = ctx->priv;
     int detect_change = 0;
     double time_ms = picref->pts * av_q2d(inlink->time_base) * 1000;
     ASS_Image *image = ass_render_frame(ass->renderer, ass->track,
                                         time_ms, &detect_change);
 
     if (detect_change)
         av_log(ctx, AV_LOG_DEBUG, "Change happened at time ms:%f\n", time_ms);
 

     overlay_ass_image(ass, picref, image);

     return ff_filter_frame(outlink, picref);

 }
 

 static const AVFilterPad ass_inputs[] = {
     {
         .name             = "default",
         .type             = AVMEDIA_TYPE_VIDEO,

         .filter_frame     = filter_frame,

         .config_props     = config_input,

         .needs_writable   = 1,

     },
     { NULL }
 };
 
 static const AVFilterPad ass_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 

 #if CONFIG_ASS_FILTER
 

 static const AVOption ass_options[] = {
     COMMON_OPTIONS

     {"shaping", "set shaping engine", OFFSET(shaping), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 1, FLAGS, "shaping_mode"},
         {"auto", NULL,                 0, AV_OPT_TYPE_CONST, {.i64 = -1},                  INT_MIN, INT_MAX, FLAGS, "shaping_mode"},
         {"simple",  "simple shaping",  0, AV_OPT_TYPE_CONST, {.i64 = ASS_SHAPING_SIMPLE},  INT_MIN, INT_MAX, FLAGS, "shaping_mode"},
         {"complex", "complex shaping", 0, AV_OPT_TYPE_CONST, {.i64 = ASS_SHAPING_COMPLEX}, INT_MIN, INT_MAX, FLAGS, "shaping_mode"},

     {NULL},
 };
 

 AVFILTER_DEFINE_CLASS(ass);
 

 static av_cold int init_ass(AVFilterContext *ctx)

 {
     AssContext *ass = ctx->priv;

     int ret = init(ctx);

 
     if (ret < 0)
         return ret;
 

     /* Initialize fonts */
     ass_set_fonts(ass->renderer, NULL, NULL, 1, NULL, 1);
 

     ass->track = ass_read_file(ass->library, ass->filename, NULL);
     if (!ass->track) {
         av_log(ctx, AV_LOG_ERROR,
                "Could not create a libass track when reading file '%s'\n",
                ass->filename);
         return AVERROR(EINVAL);
     }
     return 0;
 }
 

 AVFilter ff_vf_ass = {

     .name          = "ass",

     .description   = NULL_IF_CONFIG_SMALL("Render ASS subtitles onto input video using the libass library."),

     .priv_size     = sizeof(AssContext),

     .init          = init_ass,

     .uninit        = uninit,
     .query_formats = query_formats,

     .inputs        = ass_inputs,
     .outputs       = ass_outputs,
     .priv_class    = &ass_class,

 };

 #endif
 
 #if CONFIG_SUBTITLES_FILTER
 

 static const AVOption subtitles_options[] = {
     COMMON_OPTIONS

     {"charenc",      "set input character encoding", OFFSET(charenc),      AV_OPT_TYPE_STRING, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS},
     {"stream_index", "set stream index",             OFFSET(stream_index), AV_OPT_TYPE_INT,    { .i64 = -1 }, -1,       INT_MAX,  FLAGS},
     {"si",           "set stream index",             OFFSET(stream_index), AV_OPT_TYPE_INT,    { .i64 = -1 }, -1,       INT_MAX,  FLAGS},

     {"force_style",  "force subtitle style",         OFFSET(force_style),  AV_OPT_TYPE_STRING, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS},

     {NULL},
 };
 

 static const char * const font_mimetypes[] = {

     "application/x-truetype-font",
     "application/vnd.ms-opentype",
     "application/x-font-ttf",
     NULL
 };
 
 static int attachment_is_font(AVStream * st)
 {
     const AVDictionaryEntry *tag = NULL;
     int n;
 
     tag = av_dict_get(st->metadata, "mimetype", NULL, AV_DICT_MATCH_CASE);
 
     if (tag) {
         for (n = 0; font_mimetypes[n]; n++) {
             if (av_strcasecmp(font_mimetypes[n], tag->value) == 0)
                 return 1;
         }
     }
     return 0;
 }
 

 AVFILTER_DEFINE_CLASS(subtitles);
 

 static av_cold int init_subtitles(AVFilterContext *ctx)

 {

     int j, ret, sid;

     int k = 0;

     AVDictionary *codec_opts = NULL;

     AVFormatContext *fmt = NULL;
     AVCodecContext *dec_ctx = NULL;
     AVCodec *dec = NULL;

     const AVCodecDescriptor *dec_desc;

     AVStream *st;
     AVPacket pkt;
     AssContext *ass = ctx->priv;
 
     /* Init libass */

     ret = init(ctx);

     if (ret < 0)
         return ret;
     ass->track = ass_new_track(ass->library);
     if (!ass->track) {
         av_log(ctx, AV_LOG_ERROR, "Could not create a libass track\n");
         return AVERROR(EINVAL);
     }
 
     /* Open subtitles file */
     ret = avformat_open_input(&fmt, ass->filename, NULL, NULL);
     if (ret < 0) {
         av_log(ctx, AV_LOG_ERROR, "Unable to open %s\n", ass->filename);
         goto end;
     }
     ret = avformat_find_stream_info(fmt, NULL);
     if (ret < 0)
         goto end;
 
     /* Locate subtitles stream */

     if (ass->stream_index < 0)
         ret = av_find_best_stream(fmt, AVMEDIA_TYPE_SUBTITLE, -1, -1, NULL, 0);
     else {
         ret = -1;
         if (ass->stream_index < fmt->nb_streams) {
             for (j = 0; j < fmt->nb_streams; j++) {

                 if (fmt->streams[j]->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE) {

                     if (ass->stream_index == k) {
                         ret = j;
                         break;
                     }
                     k++;
                 }
             }
         }
     }
 

     if (ret < 0) {
         av_log(ctx, AV_LOG_ERROR, "Unable to locate subtitle stream in %s\n",
                ass->filename);
         goto end;
     }
     sid = ret;
     st = fmt->streams[sid];
 

     /* Load attached fonts */
     for (j = 0; j < fmt->nb_streams; j++) {
         AVStream *st = fmt->streams[j];

         if (st->codecpar->codec_type == AVMEDIA_TYPE_ATTACHMENT &&

             attachment_is_font(st)) {
             const AVDictionaryEntry *tag = NULL;
             tag = av_dict_get(st->metadata, "filename", NULL,
                               AV_DICT_MATCH_CASE);
 
             if (tag) {
                 av_log(ctx, AV_LOG_DEBUG, "Loading attached font: %s\n",
                        tag->value);
                 ass_add_font(ass->library, tag->value,

                              st->codecpar->extradata,
                              st->codecpar->extradata_size);

             } else {
                 av_log(ctx, AV_LOG_WARNING,
                        "Font attachment has no filename, ignored.\n");
             }
         }
     }
 
     /* Initialize fonts */
     ass_set_fonts(ass->renderer, NULL, NULL, 1, NULL, 1);
 

     /* Open decoder */

     dec = avcodec_find_decoder(st->codecpar->codec_id);

     if (!dec) {
         av_log(ctx, AV_LOG_ERROR, "Failed to find subtitle codec %s\n",

                avcodec_get_name(st->codecpar->codec_id));

         return AVERROR(EINVAL);
     }

     dec_desc = avcodec_descriptor_get(st->codecpar->codec_id);

     if (dec_desc && !(dec_desc->props & AV_CODEC_PROP_TEXT_SUB)) {

         av_log(ctx, AV_LOG_ERROR,
                "Only text based subtitles are currently supported\n");
         return AVERROR_PATCHWELCOME;
     }

     if (ass->charenc)
         av_dict_set(&codec_opts, "sub_charenc", ass->charenc, 0);

     if (LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(57,26,100))

         av_dict_set(&codec_opts, "sub_text_format", "ass", 0);

 
     dec_ctx = avcodec_alloc_context3(dec);
     if (!dec_ctx)
         return AVERROR(ENOMEM);
 
     ret = avcodec_parameters_to_context(dec_ctx, st->codecpar);
     if (ret < 0)
         goto end;
 
     /*
      * This is required by the decoding process in order to rescale the
      * timestamps: in the current API the decoded subtitles have their pts
      * expressed in AV_TIME_BASE, and thus the lavc internals need to know the
      * stream time base in order to achieve the rescaling.
      *
      * That API is old and needs to be reworked to match behaviour with A/V.
      */

     dec_ctx->pkt_timebase = st->time_base;

 
     ret = avcodec_open2(dec_ctx, NULL, &codec_opts);

     if (ret < 0)
         goto end;
 

     if (ass->force_style) {
         char **list = NULL;
         char *temp = NULL;
         char *ptr = av_strtok(ass->force_style, ",", &temp);
         int i = 0;
         while (ptr) {
             av_dynarray_add(&list, &i, ptr);
             if (!list) {
                 ret = AVERROR(ENOMEM);
                 goto end;
             }
             ptr = av_strtok(NULL, ",", &temp);
         }
         av_dynarray_add(&list, &i, NULL);
         if (!list) {
             ret = AVERROR(ENOMEM);
             goto end;
         }
         ass_set_style_overrides(ass->library, list);
         av_free(list);
     }

     /* Decode subtitles and push them into the renderer (libass) */
     if (dec_ctx->subtitle_header)
         ass_process_codec_private(ass->track,
                                   dec_ctx->subtitle_header,
                                   dec_ctx->subtitle_header_size);
     av_init_packet(&pkt);
     pkt.data = NULL;
     pkt.size = 0;
     while (av_read_frame(fmt, &pkt) >= 0) {
         int i, got_subtitle;

         AVSubtitle sub = {0};

 
         if (pkt.stream_index == sid) {
             ret = avcodec_decode_subtitle2(dec_ctx, &sub, &got_subtitle, &pkt);

             if (ret < 0) {
                 av_log(ctx, AV_LOG_WARNING, "Error decoding: %s (ignored)\n",
                        av_err2str(ret));
             } else if (got_subtitle) {

                 const int64_t start_time = av_rescale_q(sub.pts, AV_TIME_BASE_Q, av_make_q(1, 1000));
                 const int64_t duration   = sub.end_display_time;

                 for (i = 0; i < sub.num_rects; i++) {
                     char *ass_line = sub.rects[i]->ass;
                     if (!ass_line)
                         break;

                     if (LIBAVCODEC_VERSION_INT < AV_VERSION_INT(57,25,100))
                         ass_process_data(ass->track, ass_line, strlen(ass_line));
                     else
                         ass_process_chunk(ass->track, ass_line, strlen(ass_line),
                                           start_time, duration);

                 }

             }

         }

         av_packet_unref(&pkt);

         avsubtitle_free(&sub);
     }
 
 end:

     av_dict_free(&codec_opts);

     avcodec_close(dec_ctx);

     avcodec_free_context(&dec_ctx);

     avformat_close_input(&fmt);

     return ret;
 }
 

 AVFilter ff_vf_subtitles = {

     .name          = "subtitles",

     .description   = NULL_IF_CONFIG_SMALL("Render text subtitles onto input video using the libass library."),

     .priv_size     = sizeof(AssContext),
     .init          = init_subtitles,
     .uninit        = uninit,
     .query_formats = query_formats,
     .inputs        = ass_inputs,
     .outputs       = ass_outputs,
     .priv_class    = &subtitles_class,
 };
 #endif