/*
  * Copyright (c) 2015 Derek Buitenhuis
  *
  * 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/opt.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
 #define DEFAULT_LENGTH 300
 
 typedef struct ReverseContext {
     int nb_frames;
     AVFrame **frames;
     unsigned int frames_size;
     unsigned int pts_size;
     int64_t *pts;
     int flush_idx;
 } ReverseContext;
 
 static av_cold int init(AVFilterContext *ctx)
 {
     ReverseContext *s = ctx->priv;
 
     s->pts = av_fast_realloc(NULL, &s->pts_size,
                              DEFAULT_LENGTH * sizeof(*(s->pts)));
     if (!s->pts)
         return AVERROR(ENOMEM);
 
     s->frames = av_fast_realloc(NULL, &s->frames_size,
                                 DEFAULT_LENGTH * sizeof(*(s->frames)));
     if (!s->frames) {
         av_freep(&s->pts);
         return AVERROR(ENOMEM);
     }
 
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     ReverseContext *s = ctx->priv;
 
     av_freep(&s->pts);
     av_freep(&s->frames);
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
     ReverseContext *s    = ctx->priv;

     void *ptr;

     if (s->nb_frames + 1 > s->pts_size / sizeof(*(s->pts))) {

         ptr = av_fast_realloc(s->pts, &s->pts_size, s->pts_size * 2);
         if (!ptr)
             return AVERROR(ENOMEM);
         s->pts = ptr;

     }

     if (s->nb_frames + 1 > s->frames_size / sizeof(*(s->frames))) {

         ptr = av_fast_realloc(s->frames, &s->frames_size, s->frames_size * 2);
         if (!ptr)
             return AVERROR(ENOMEM);
         s->frames = ptr;
     }
 
     s->frames[s->nb_frames] = in;
     s->pts[s->nb_frames]    = in->pts;
     s->nb_frames++;
 
     return 0;
 }
 

 #if CONFIG_REVERSE_FILTER
 

 static int request_frame(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     ReverseContext *s = ctx->priv;
     int ret;
 
     ret = ff_request_frame(ctx->inputs[0]);
 
     if (ret == AVERROR_EOF && s->nb_frames > 0) {
         AVFrame *out = s->frames[s->nb_frames - 1];
         out->pts     = s->pts[s->flush_idx++];
         ret          = ff_filter_frame(outlink, out);
         s->nb_frames--;
     }
 
     return ret;
 }
 
 static const AVFilterPad reverse_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad reverse_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .request_frame = request_frame,
     },
     { NULL }
 };
 
 AVFilter ff_vf_reverse = {
     .name        = "reverse",
     .description = NULL_IF_CONFIG_SMALL("Reverse a clip."),
     .priv_size   = sizeof(ReverseContext),
     .init        = init,
     .uninit      = uninit,
     .inputs      = reverse_inputs,
     .outputs     = reverse_outputs,
 };

 
 #endif /* CONFIG_REVERSE_FILTER */
 
 #if CONFIG_AREVERSE_FILTER
 
 static int query_formats(AVFilterContext *ctx)
 {
     AVFilterFormats *formats;
     AVFilterChannelLayouts *layouts;
     int ret;
 

     layouts = ff_all_channel_counts();

     if (!layouts)
         return AVERROR(ENOMEM);
     ret = ff_set_common_channel_layouts(ctx, layouts);
     if (ret < 0)
         return ret;
 
     ret = ff_set_common_formats(ctx, ff_planar_sample_fmts());
     if (ret < 0)
         return ret;
 
     formats = ff_all_samplerates();
     if (!formats)
         return AVERROR(ENOMEM);
     return ff_set_common_samplerates(ctx, formats);
 }
 
 static int areverse_request_frame(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     ReverseContext *s = ctx->priv;
     int ret, p, i, j;
 
     ret = ff_request_frame(ctx->inputs[0]);
 
     if (ret == AVERROR_EOF && s->nb_frames > 0) {
         AVFrame *out = s->frames[s->nb_frames - 1];
         out->pts     = s->pts[s->flush_idx++];
 
         for (p = 0; p < outlink->channels; p++) {
             switch (outlink->format) {
             case AV_SAMPLE_FMT_U8P: {
                 uint8_t *dst = (uint8_t *)out->extended_data[p];
                 for (i = 0, j = out->nb_samples - 1; i < j; i++, j--)
                     FFSWAP(uint8_t, dst[i], dst[j]);
             }
                 break;
             case AV_SAMPLE_FMT_S16P: {
                 int16_t *dst = (int16_t *)out->extended_data[p];
                 for (i = 0, j = out->nb_samples - 1; i < j; i++, j--)
                     FFSWAP(int16_t, dst[i], dst[j]);
             }
                 break;
             case AV_SAMPLE_FMT_S32P: {
                 int32_t *dst = (int32_t *)out->extended_data[p];
                 for (i = 0, j = out->nb_samples - 1; i < j; i++, j--)
                     FFSWAP(int32_t, dst[i], dst[j]);
             }
                 break;
             case AV_SAMPLE_FMT_FLTP: {
                 float *dst = (float *)out->extended_data[p];
                 for (i = 0, j = out->nb_samples - 1; i < j; i++, j--)
                     FFSWAP(float, dst[i], dst[j]);
             }
                 break;
             case AV_SAMPLE_FMT_DBLP: {
                 double *dst = (double *)out->extended_data[p];
                 for (i = 0, j = out->nb_samples - 1; i < j; i++, j--)
                     FFSWAP(double, dst[i], dst[j]);
             }
                 break;
             }
         }
 
         ret = ff_filter_frame(outlink, out);
         s->nb_frames--;
     }
 
     return ret;
 }
 
 static const AVFilterPad areverse_inputs[] = {
     {
         .name           = "default",
         .type           = AVMEDIA_TYPE_AUDIO,
         .filter_frame   = filter_frame,
         .needs_writable = 1,
     },
     { NULL }
 };
 
 static const AVFilterPad areverse_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_AUDIO,
         .request_frame = areverse_request_frame,
     },
     { NULL }
 };
 
 AVFilter ff_af_areverse = {
     .name          = "areverse",
     .description   = NULL_IF_CONFIG_SMALL("Reverse an audio clip."),
     .query_formats = query_formats,
     .priv_size     = sizeof(ReverseContext),
     .init          = init,
     .uninit        = uninit,
     .inputs        = areverse_inputs,
     .outputs       = areverse_outputs,
 };
 
 #endif /* CONFIG_AREVERSE_FILTER */