/*
  * Copyright (c) 2015 Arwa Arif <arwaarif1994@gmail.com>
  *
  * 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
  * FFT domain filtering.
  */
 
 #include "libavfilter/internal.h"
 #include "libavutil/common.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 #include "libavcodec/avfft.h"
 #include "libavutil/eval.h"
 

 #define MAX_PLANES 4
 

 enum EvalMode {
     EVAL_MODE_INIT,
     EVAL_MODE_FRAME,
     EVAL_MODE_NB
 };
 

 typedef struct FFTFILTContext {

     const AVClass *class;
 

     int eval_mode;

     int depth;
     int nb_planes;
     int planewidth[MAX_PLANES];
     int planeheight[MAX_PLANES];
 

     RDFTContext *hrdft[MAX_PLANES];
     RDFTContext *vrdft[MAX_PLANES];
     RDFTContext *ihrdft[MAX_PLANES];
     RDFTContext *ivrdft[MAX_PLANES];

     int rdft_hbits[MAX_PLANES];
     int rdft_vbits[MAX_PLANES];
     size_t rdft_hlen[MAX_PLANES];
     size_t rdft_vlen[MAX_PLANES];
     FFTSample *rdft_hdata[MAX_PLANES];
     FFTSample *rdft_vdata[MAX_PLANES];
 
     int dc[MAX_PLANES];
     char *weight_str[MAX_PLANES];
     AVExpr *weight_expr[MAX_PLANES];
     double *weight[MAX_PLANES];

 
 } FFTFILTContext;
 

 static const char *const var_names[] = {   "X",   "Y",   "W",   "H",   "N", NULL        };
 enum                                   { VAR_X, VAR_Y, VAR_W, VAR_H, VAR_N, VAR_VARS_NB };

 
 enum { Y = 0, U, V };
 
 #define OFFSET(x) offsetof(FFTFILTContext, x)
 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 
 static const AVOption fftfilt_options[] = {
     { "dc_Y",  "adjust gain in Y plane",              OFFSET(dc[Y]),      AV_OPT_TYPE_INT,    {.i64 = 0},      0,     1000,     FLAGS },
     { "dc_U",  "adjust gain in U plane",              OFFSET(dc[U]),      AV_OPT_TYPE_INT,    {.i64 = 0},      0,     1000,     FLAGS },
     { "dc_V",  "adjust gain in V plane",              OFFSET(dc[V]),      AV_OPT_TYPE_INT,    {.i64 = 0},      0,     1000,     FLAGS },
     { "weight_Y", "set luminance expression in Y plane",   OFFSET(weight_str[Y]), AV_OPT_TYPE_STRING, {.str = "1"}, CHAR_MIN, CHAR_MAX, FLAGS },
     { "weight_U", "set chrominance expression in U plane", OFFSET(weight_str[U]), AV_OPT_TYPE_STRING, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
     { "weight_V", "set chrominance expression in V plane", OFFSET(weight_str[V]), AV_OPT_TYPE_STRING, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS },

     { "eval", "specify when to evaluate expressions", OFFSET(eval_mode), AV_OPT_TYPE_INT, {.i64 = EVAL_MODE_INIT}, 0, EVAL_MODE_NB-1, FLAGS, "eval" },
          { "init",  "eval expressions once during initialization", 0, AV_OPT_TYPE_CONST, {.i64=EVAL_MODE_INIT},  .flags = FLAGS, .unit = "eval" },
          { "frame", "eval expressions per-frame",                  0, AV_OPT_TYPE_CONST, {.i64=EVAL_MODE_FRAME}, .flags = FLAGS, .unit = "eval" },

     {NULL},
 };
 
 AVFILTER_DEFINE_CLASS(fftfilt);
 
 static inline double lum(void *priv, double x, double y, int plane)
 {

     FFTFILTContext *s = priv;
     return s->rdft_vdata[plane][(int)x * s->rdft_vlen[plane] + (int)y];

 }
 
 static double weight_Y(void *priv, double x, double y) { return lum(priv, x, y, Y); }
 static double weight_U(void *priv, double x, double y) { return lum(priv, x, y, U); }
 static double weight_V(void *priv, double x, double y) { return lum(priv, x, y, V); }
 
 static void copy_rev (FFTSample *dest, int w, int w2)
 {
     int i;
 
     for (i = w; i < w + (w2-w)/2; i++)
         dest[i] = dest[2*w - i - 1];
 
     for (; i < w2; i++)
         dest[i] = dest[w2 - i];
 }
 
 /*Horizontal pass - RDFT*/

 static void rdft_horizontal(FFTFILTContext *s, AVFrame *in, int w, int h, int plane)

 {
     int i, j;
 
     for (i = 0; i < h; i++) {
         for (j = 0; j < w; j++)

             s->rdft_hdata[plane][i * s->rdft_hlen[plane] + j] = *(in->data[plane] + in->linesize[plane] * i + j);

         copy_rev(s->rdft_hdata[plane] + i * s->rdft_hlen[plane], w, s->rdft_hlen[plane]);

     }
 
     for (i = 0; i < h; i++)

         av_rdft_calc(s->hrdft[plane], s->rdft_hdata[plane] + i * s->rdft_hlen[plane]);

 }
 
 /*Vertical pass - RDFT*/

 static void rdft_vertical(FFTFILTContext *s, int h, int plane)

 {
     int i, j;
 

     for (i = 0; i < s->rdft_hlen[plane]; i++) {

         for (j = 0; j < h; j++)

             s->rdft_vdata[plane][i * s->rdft_vlen[plane] + j] =
             s->rdft_hdata[plane][j * s->rdft_hlen[plane] + i];
         copy_rev(s->rdft_vdata[plane] + i * s->rdft_vlen[plane], h, s->rdft_vlen[plane]);

     }
 

     for (i = 0; i < s->rdft_hlen[plane]; i++)

         av_rdft_calc(s->vrdft[plane], s->rdft_vdata[plane] + i * s->rdft_vlen[plane]);

 }
 /*Vertical pass - IRDFT*/

 static void irdft_vertical(FFTFILTContext *s, int h, int plane)

 {
     int i, j;

     for (i = 0; i < s->rdft_hlen[plane]; i++)

         av_rdft_calc(s->ivrdft[plane], s->rdft_vdata[plane] + i * s->rdft_vlen[plane]);

     for (i = 0; i < s->rdft_hlen[plane]; i++)

         for (j = 0; j < h; j++)

             s->rdft_hdata[plane][j * s->rdft_hlen[plane] + i] =
             s->rdft_vdata[plane][i * s->rdft_vlen[plane] + j];

 }
 
 /*Horizontal pass - IRDFT*/

 static void irdft_horizontal(FFTFILTContext *s, AVFrame *out, int w, int h, int plane)

 {
     int i, j;

     for (i = 0; i < h; i++)

         av_rdft_calc(s->ihrdft[plane], s->rdft_hdata[plane] + i * s->rdft_hlen[plane]);

 
     for (i = 0; i < h; i++)
         for (j = 0; j < w; j++)

             *(out->data[plane] + out->linesize[plane] * i + j) = av_clip(s->rdft_hdata[plane][i
                                                                          *s->rdft_hlen[plane] + j] * 4 /
                                                                          (s->rdft_hlen[plane] *
                                                                           s->rdft_vlen[plane]), 0, 255);

 }
 
 static av_cold int initialize(AVFilterContext *ctx)
 {

     FFTFILTContext *s = ctx->priv;

     int ret = 0, plane;
 

     if (!s->dc[U] && !s->dc[V]) {
         s->dc[U] = s->dc[Y];
         s->dc[V] = s->dc[Y];

     } else {

         if (!s->dc[U]) s->dc[U] = s->dc[V];
         if (!s->dc[V]) s->dc[V] = s->dc[U];

     }
 

     if (!s->weight_str[U] && !s->weight_str[V]) {
         s->weight_str[U] = av_strdup(s->weight_str[Y]);
         s->weight_str[V] = av_strdup(s->weight_str[Y]);

     } else {

         if (!s->weight_str[U]) s->weight_str[U] = av_strdup(s->weight_str[V]);
         if (!s->weight_str[V]) s->weight_str[V] = av_strdup(s->weight_str[U]);

     }
 
     for (plane = 0; plane < 3; plane++) {
         static double (*p[])(void *, double, double) = { weight_Y, weight_U, weight_V };
         const char *const func2_names[] = {"weight_Y", "weight_U", "weight_V", NULL };
         double (*func2[])(void *, double, double) = { weight_Y, weight_U, weight_V, p[plane], NULL };
 

         ret = av_expr_parse(&s->weight_expr[plane], s->weight_str[plane], var_names,

                             NULL, NULL, func2_names, func2, 0, ctx);
         if (ret < 0)
             break;
     }
     return ret;
 }
 

 static void do_eval(FFTFILTContext *s, AVFilterLink *inlink, int plane)
 {
     double values[VAR_VARS_NB];
     int i, j;
 
     values[VAR_N] = inlink->frame_count_out;
     values[VAR_W] = s->planewidth[plane];
     values[VAR_H] = s->planeheight[plane];
 
     for (i = 0; i < s->rdft_hlen[plane]; i++) {
         values[VAR_X] = i;
         for (j = 0; j < s->rdft_vlen[plane]; j++) {
             values[VAR_Y] = j;
             s->weight[plane][i * s->rdft_vlen[plane] + j] =
             av_expr_eval(s->weight_expr[plane], values, s);
         }
     }
 }
 

 static int config_props(AVFilterLink *inlink)
 {

     FFTFILTContext *s = inlink->dst->priv;

     const AVPixFmtDescriptor *desc;

     int rdft_hbits, rdft_vbits, i, plane;

 
     desc = av_pix_fmt_desc_get(inlink->format);

     s->depth = desc->comp[0].depth;
     s->planewidth[1] = s->planewidth[2] = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
     s->planewidth[0] = s->planewidth[3] = inlink->w;
     s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
     s->planeheight[0] = s->planeheight[3] = inlink->h;
 
     s->nb_planes = av_pix_fmt_count_planes(inlink->format);
 

     for (i = 0; i < desc->nb_components; i++) {

         int w = s->planewidth[i];
         int h = s->planeheight[i];

 
         /* RDFT - Array initialization for Horizontal pass*/

         for (rdft_hbits = 1; 1 << rdft_hbits < w*10/9; rdft_hbits++);

         s->rdft_hbits[i] = rdft_hbits;
         s->rdft_hlen[i] = 1 << rdft_hbits;
         if (!(s->rdft_hdata[i] = av_malloc_array(h, s->rdft_hlen[i] * sizeof(FFTSample))))

             return AVERROR(ENOMEM);
 

         if (!(s->hrdft[i] = av_rdft_init(s->rdft_hbits[i], DFT_R2C)))
             return AVERROR(ENOMEM);
         if (!(s->ihrdft[i] = av_rdft_init(s->rdft_hbits[i], IDFT_C2R)))
             return AVERROR(ENOMEM);
 

         /* RDFT - Array initialization for Vertical pass*/

         for (rdft_vbits = 1; 1 << rdft_vbits < h*10/9; rdft_vbits++);

         s->rdft_vbits[i] = rdft_vbits;
         s->rdft_vlen[i] = 1 << rdft_vbits;
         if (!(s->rdft_vdata[i] = av_malloc_array(s->rdft_hlen[i], s->rdft_vlen[i] * sizeof(FFTSample))))

             return AVERROR(ENOMEM);

 
         if (!(s->vrdft[i] = av_rdft_init(s->rdft_vbits[i], DFT_R2C)))
             return AVERROR(ENOMEM);
         if (!(s->ivrdft[i] = av_rdft_init(s->rdft_vbits[i], IDFT_C2R)))
             return AVERROR(ENOMEM);

     }
 
     /*Luminance value - Array initialization*/

     for (plane = 0; plane < 3; plane++) {

         if(!(s->weight[plane] = av_malloc_array(s->rdft_hlen[plane], s->rdft_vlen[plane] * sizeof(double))))

             return AVERROR(ENOMEM);

 
         if (s->eval_mode == EVAL_MODE_INIT)
             do_eval(s, inlink, plane);

     }
     return 0;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = inlink->dst->outputs[0];

     FFTFILTContext *s = ctx->priv;

     AVFrame *out;
     int i, j, plane;
 
     out = ff_get_video_buffer(outlink, inlink->w, inlink->h);

     if (!out) {
         av_frame_free(&in);

         return AVERROR(ENOMEM);

     }

 
     av_frame_copy_props(out, in);
 

     for (plane = 0; plane < s->nb_planes; plane++) {
         int w = s->planewidth[plane];
         int h = s->planeheight[plane];

         if (s->eval_mode == EVAL_MODE_FRAME)
             do_eval(s, inlink, plane);
 

         rdft_horizontal(s, in, w, h, plane);
         rdft_vertical(s, h, plane);

 
         /*Change user defined parameters*/

         for (i = 0; i < s->rdft_hlen[plane]; i++)
             for (j = 0; j < s->rdft_vlen[plane]; j++)
                 s->rdft_vdata[plane][i * s->rdft_vlen[plane] + j] *=
                   s->weight[plane][i * s->rdft_vlen[plane] + j];

         s->rdft_vdata[plane][0] += s->rdft_hlen[plane] * s->rdft_vlen[plane] * s->dc[plane];

         irdft_vertical(s, h, plane);
         irdft_horizontal(s, out, w, h, plane);

     }
 
     av_frame_free(&in);
     return ff_filter_frame(outlink, out);
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {

     FFTFILTContext *s = ctx->priv;

     int i;

     for (i = 0; i < MAX_PLANES; i++) {

         av_free(s->rdft_hdata[i]);
         av_free(s->rdft_vdata[i]);
         av_expr_free(s->weight_expr[i]);
         av_free(s->weight[i]);

         av_rdft_end(s->hrdft[i]);
         av_rdft_end(s->ihrdft[i]);
         av_rdft_end(s->vrdft[i]);
         av_rdft_end(s->ivrdft[i]);

     }
 }
 
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pixel_fmts_fftfilt[] = {
         AV_PIX_FMT_GRAY8,

         AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUVJ444P,
         AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUVJ420P,
         AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUVJ422P,

         AV_PIX_FMT_NONE
     };
 

     AVFilterFormats *fmts_list = ff_make_format_list(pixel_fmts_fftfilt);
     if (!fmts_list)
         return AVERROR(ENOMEM);
     return ff_set_common_formats(ctx, fmts_list);

 }
 
 static const AVFilterPad fftfilt_inputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
         .config_props = config_props,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad fftfilt_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 
 AVFilter ff_vf_fftfilt = {
     .name            = "fftfilt",

     .description     = NULL_IF_CONFIG_SMALL("Apply arbitrary expressions to pixels in frequency domain."),

     .priv_size       = sizeof(FFTFILTContext),
     .priv_class      = &fftfilt_class,
     .inputs          = fftfilt_inputs,
     .outputs         = fftfilt_outputs,
     .query_formats   = query_formats,
     .init            = initialize,
     .uninit          = uninit,

     .flags           = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,

 };