/*
  * Copyright (c) 2015 Paul B Mahol
  *
  * 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 "libavutil/avassert.h"

 #include "libavutil/avstring.h"
 #include "libavutil/common.h"
 #include "libavutil/internal.h"
 #include "libavutil/opt.h"
 
 #include "avfilter.h"
 #include "internal.h"
 #include "video.h"
 
 typedef struct ShuffleFramesContext {
     const AVClass *class;
     char *mapping;
     AVFrame **frames;
     int *map;
     int64_t *pts;
     int in_frames;
     int nb_frames;
 } ShuffleFramesContext;
 
 static av_cold int init(AVFilterContext *ctx)
 {
     ShuffleFramesContext *s = ctx->priv;
     char *mapping, *saveptr = NULL, *p;
     int n, nb_items;
 
     nb_items = 1;
     for (p = s->mapping; *p; p++) {
         if (*p == '|' || *p == ' ')
             nb_items++;
     }
 
     s->frames = av_calloc(nb_items, sizeof(*s->frames));
     s->map    = av_calloc(nb_items, sizeof(*s->map));
     s->pts    = av_calloc(nb_items, sizeof(*s->pts));
     if (!s->map || !s->frames || !s->pts) {
         return AVERROR(ENOMEM);
     }
 
     mapping = av_strdup(s->mapping);
     if (!mapping)
         return AVERROR(ENOMEM);
 
     for (n = 0; n < nb_items; n++) {
         char *map = av_strtok(n == 0 ? mapping : NULL, " |", &saveptr);
         if (!map || sscanf(map, "%d", &s->map[n]) != 1) {
             av_free(mapping);
             return AVERROR(EINVAL);
         }
 

         if (s->map[n] < -1 || s->map[n] >= nb_items) {

             av_log(ctx, AV_LOG_ERROR, "Index out of range.\n");
             av_free(mapping);
             return AVERROR(EINVAL);
         }
     }
 
     s->nb_frames = nb_items;
     av_free(mapping);
     return 0;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
 {
     AVFilterContext    *ctx = inlink->dst;
     ShuffleFramesContext *s = ctx->priv;

     int ret = 0;

 
     if (s->in_frames < s->nb_frames) {
         s->frames[s->in_frames] = frame;
         s->pts[s->in_frames] = frame->pts;
         s->in_frames++;

     }
 
     if (s->in_frames == s->nb_frames) {

         int n, x;
 
         for (n = 0; n < s->nb_frames; n++) {
             AVFrame *out;
 
             x = s->map[n];

             if (x >= 0) {
                 out = av_frame_clone(s->frames[x]);
                 if (!out)
                     return AVERROR(ENOMEM);
                 out->pts = s->pts[n];
                 ret = ff_filter_frame(ctx->outputs[0], out);
             }

             s->in_frames--;
         }
 
         for (n = 0; n < s->nb_frames; n++)
             av_frame_free(&s->frames[n]);

     }

 
     return ret;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     ShuffleFramesContext *s = ctx->priv;
 

     while (s->in_frames > 0) {
         s->in_frames--;
         av_frame_free(&s->frames[s->in_frames]);
     }
 

     av_freep(&s->frames);
     av_freep(&s->map);
     av_freep(&s->pts);
 }
 
 #define OFFSET(x) offsetof(ShuffleFramesContext, x)
 #define FLAGS (AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_VIDEO_PARAM)
 static const AVOption shuffleframes_options[] = {
     { "mapping", "set destination indexes of input frames",  OFFSET(mapping), AV_OPT_TYPE_STRING, {.str="0"}, 0, 0, FLAGS },
     { NULL },
 };
 
 AVFILTER_DEFINE_CLASS(shuffleframes);
 
 static const AVFilterPad shuffleframes_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
     },
     { NULL },
 };
 
 static const AVFilterPad shuffleframes_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL },
 };
 
 AVFilter ff_vf_shuffleframes = {
     .name          = "shuffleframes",

     .description   = NULL_IF_CONFIG_SMALL("Shuffle video frames."),

     .priv_size     = sizeof(ShuffleFramesContext),
     .priv_class    = &shuffleframes_class,
     .init          = init,
     .uninit        = uninit,
     .inputs        = shuffleframes_inputs,
     .outputs       = shuffleframes_outputs,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
 };