/*
  * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
  * Copyright (c) 2013 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 General Public
  * License as published by the Free Software Foundation; either
  * version 2 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 General Public License for more details.
  *
  * You should have received a copy of the GNU 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
  * noise generator
  */
 
 #include "libavutil/opt.h"
 #include "libavutil/imgutils.h"

 #include "libavutil/lfg.h"

 #include "libavutil/parseutils.h"
 #include "libavutil/pixdesc.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
 #define MAX_NOISE 4096
 #define MAX_SHIFT 1024
 #define MAX_RES (MAX_NOISE-MAX_SHIFT)
 
 #define NOISE_UNIFORM  1
 #define NOISE_TEMPORAL 2
 #define NOISE_QUALITY  4
 #define NOISE_AVERAGED 8
 #define NOISE_PATTERN  16
 
 typedef struct {
     int strength;
     unsigned flags;
     int shiftptr;

     AVLFG lfg;

     int seed;
     int8_t *noise;
     int8_t *prev_shift[MAX_RES][3];
 } FilterParams;
 
 typedef struct {
     const AVClass *class;
     int nb_planes;
     int linesize[4];
     int height[4];
     FilterParams all;
     FilterParams param[4];
     int rand_shift[MAX_RES];
     int rand_shift_init;
 } NoiseContext;
 
 #define OFFSET(x) offsetof(NoiseContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 
 #define NOISE_PARAMS(name, x, param)                                                                                             \
     {#name"_seed", "set component #"#x" noise seed", OFFSET(param.seed), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, FLAGS},        \
     {#name"_strength", "set component #"#x" strength", OFFSET(param.strength), AV_OPT_TYPE_INT, {.i64=0}, 0, 100, FLAGS},        \
     {#name"s",         "set component #"#x" strength", OFFSET(param.strength), AV_OPT_TYPE_INT, {.i64=0}, 0, 100, FLAGS},        \
     {#name"_flags", "set component #"#x" flags", OFFSET(param.flags), AV_OPT_TYPE_FLAGS, {.i64=0}, 0, 31, FLAGS, #name"_flags"}, \
     {#name"f", "set component #"#x" flags", OFFSET(param.flags), AV_OPT_TYPE_FLAGS, {.i64=0}, 0, 31, FLAGS, #name"_flags"},      \
     {"a", "averaged noise", 0, AV_OPT_TYPE_CONST, {.i64=NOISE_AVERAGED}, 0, 0, FLAGS, #name"_flags"},                            \
     {"p", "(semi)regular pattern", 0, AV_OPT_TYPE_CONST, {.i64=NOISE_PATTERN},  0, 0, FLAGS, #name"_flags"},                     \
     {"q", "high quality",   0, AV_OPT_TYPE_CONST, {.i64=NOISE_QUALITY},  0, 0, FLAGS, #name"_flags"},                            \
     {"t", "temporal noise", 0, AV_OPT_TYPE_CONST, {.i64=NOISE_TEMPORAL}, 0, 0, FLAGS, #name"_flags"},                            \
     {"u", "uniform noise",  0, AV_OPT_TYPE_CONST, {.i64=NOISE_UNIFORM},  0, 0, FLAGS, #name"_flags"},
 
 static const AVOption noise_options[] = {
     NOISE_PARAMS(all, 0, all)
     NOISE_PARAMS(c0,  0, param[0])
     NOISE_PARAMS(c1,  1, param[1])
     NOISE_PARAMS(c2,  2, param[2])
     NOISE_PARAMS(c3,  3, param[3])
     {NULL}
 };
 
 AVFILTER_DEFINE_CLASS(noise);
 
 static const int8_t patt[4] = { -1, 0, 1, 0 };
 

 #define RAND_N(range) ((int) ((double) range * av_lfg_get(lfg) / (UINT_MAX + 1.0)))

 static int init_noise(NoiseContext *n, int comp)
 {
     int8_t *noise = av_malloc(MAX_NOISE * sizeof(int8_t));
     FilterParams *fp = &n->param[comp];

     AVLFG *lfg = &n->param[comp].lfg;

     int strength = fp->strength;
     int flags = fp->flags;
     int i, j;
 
     if (!noise)
         return AVERROR(ENOMEM);
 

     av_lfg_init(&fp->lfg, fp->seed);

 
     for (i = 0, j = 0; i < MAX_NOISE; i++, j++) {
         if (flags & NOISE_UNIFORM) {
             if (flags & NOISE_AVERAGED) {
                 if (flags & NOISE_PATTERN) {
                     noise[i] = (RAND_N(strength) - strength / 2) / 6
                         + patt[j % 4] * strength * 0.25 / 3;
                 } else {
                     noise[i] = (RAND_N(strength) - strength / 2) / 3;
                 }
             } else {
                 if (flags & NOISE_PATTERN) {
                     noise[i] = (RAND_N(strength) - strength / 2) / 2
                         + patt[j % 4] * strength * 0.25;
                 } else {
                     noise[i] = RAND_N(strength) - strength / 2;
                 }
             }
         } else {
             double x1, x2, w, y1;
             do {

                 x1 = 2.0 * av_lfg_get(lfg) / (float)RAND_MAX - 1.0;
                 x2 = 2.0 * av_lfg_get(lfg) / (float)RAND_MAX - 1.0;

                 w = x1 * x1 + x2 * x2;
             } while (w >= 1.0);
 
             w   = sqrt((-2.0 * log(w)) / w);
             y1  = x1 * w;
             y1 *= strength / sqrt(3.0);
             if (flags & NOISE_PATTERN) {
                 y1 /= 2;
                 y1 += patt[j % 4] * strength * 0.35;
             }
             y1 = av_clipf(y1, -128, 127);
             if (flags & NOISE_AVERAGED)
                 y1 /= 3.0;
             noise[i] = (int)y1;
         }
         if (RAND_N(6) == 0)
             j--;
     }
 
     for (i = 0; i < MAX_RES; i++)
         for (j = 0; j < 3; j++)

             fp->prev_shift[i][j] = noise + (av_lfg_get(lfg) & (MAX_SHIFT - 1));

 
     if (!n->rand_shift_init) {
         for (i = 0; i < MAX_RES; i++)

             n->rand_shift[i] = av_lfg_get(lfg) & (MAX_SHIFT - 1);

         n->rand_shift_init = 1;
     }
 
     fp->noise = noise;
     fp->shiftptr = 0;
     return 0;
 }
 
 static av_cold int init(AVFilterContext *ctx, const char *args)
 {
     NoiseContext *n = ctx->priv;
     int ret, i;
 
     n->class = &noise_class;
     av_opt_set_defaults(n);
 
     if ((ret = av_set_options_string(n, args, "=", ":")) < 0)
         return ret;
 
     for (i = 0; i < 4; i++) {
         if (n->all.seed >= 0)
             n->param[i].seed = n->all.seed;
         else
             n->param[i].seed = 123457;
         if (n->all.strength)
             n->param[i].strength = n->all.strength;
         if (n->all.flags)
             n->param[i].flags = n->all.flags;
     }
 
     for (i = 0; i < 4; i++) {
         if (n->param[i].strength && ((ret = init_noise(n, i)) < 0))
             return ret;
     }
 
     return 0;
 }
 
 static int query_formats(AVFilterContext *ctx)
 {
     AVFilterFormats *formats = NULL;
     int fmt;
 
     for (fmt = 0; fmt < AV_PIX_FMT_NB; fmt++) {
         const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
         if (desc->flags & PIX_FMT_PLANAR && !((desc->comp[0].depth_minus1 + 1) & 7))
             ff_add_format(&formats, fmt);
     }
 
     ff_set_common_formats(ctx, formats);
     return 0;
 }
 
 static int config_input(AVFilterLink *inlink)
 {
     NoiseContext *n = inlink->dst->priv;
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
     int i, ret;
 
     for (i = 0; i < desc->nb_components; i++)
         n->nb_planes = FFMAX(n->nb_planes, desc->comp[i].plane);
     n->nb_planes++;
 
     if ((ret = av_image_fill_linesizes(n->linesize, inlink->format, inlink->w)) < 0)
         return ret;
 
     n->height[1] = n->height[2] = inlink->h >> desc->log2_chroma_h;
     n->height[0] = n->height[3] = inlink->h;
 
     return 0;
 }
 
 static void line_noise(uint8_t *dst, const uint8_t *src, int8_t *noise,
                        int len, int shift)
 {
     int i;
 
     noise += shift;
     for (i = 0; i < len; i++) {
         int v = src[i] + noise[i];
 
         dst[i] = av_clip_uint8(v);
     }
 }
 
 static void line_noise_avg(uint8_t *dst, const uint8_t *src,
                            int len, int8_t **shift)
 {
     int i;
     int8_t *src2 = (int8_t*)src;
 
     for (i = 0; i < len; i++) {
         const int n = shift[0][i] + shift[1][i] + shift[2][i];
         dst[i] = src2[i] + ((n * src2[i]) >> 7);
     }
 }
 
 static void noise(uint8_t *dst, const uint8_t *src,
                   int dst_linesize, int src_linesize,
                   int width, int height, NoiseContext *n, int comp)
 {
     int8_t *noise = n->param[comp].noise;
     int flags = n->param[comp].flags;

     AVLFG *lfg = &n->param[comp].lfg;

     int shift, y;
 
     if (!noise) {
         if (dst != src) {
             for (y = 0; y < height; y++) {
                 memcpy(dst, src, width);
                 dst += dst_linesize;
                 src += src_linesize;
             }
         }
 
         return;
     }
 
     for (y = 0; y < height; y++) {
         if (flags & NOISE_TEMPORAL)

             shift = av_lfg_get(lfg) & (MAX_SHIFT - 1);

         else
             shift = n->rand_shift[y];
 
         if (!(flags & NOISE_QUALITY))
             shift &= ~7;
 
         if (flags & NOISE_AVERAGED) {
             line_noise_avg(dst, src, width, n->param[comp].prev_shift[y]);
             n->param[comp].prev_shift[y][n->param[comp].shiftptr] = noise + shift;
         } else {
             line_noise(dst, src, noise, width, shift);
         }
         dst += dst_linesize;
         src += src_linesize;
     }
 
     n->param[comp].shiftptr++;
     if (n->param[comp].shiftptr == 3)
         n->param[comp].shiftptr = 0;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
 {
     NoiseContext *n = inlink->dst->priv;
     AVFilterLink *outlink = inlink->dst->outputs[0];
     AVFilterBufferRef *out;
     int ret, i;
 
     if (inpicref->perms & AV_PERM_WRITE) {
         out = inpicref;
     } else {
         out = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
         if (!out) {
             avfilter_unref_bufferp(&inpicref);
             return AVERROR(ENOMEM);
         }
         avfilter_copy_buffer_ref_props(out, inpicref);
     }
 
     for (i = 0; i < n->nb_planes; i++)
         noise(out->data[i], inpicref->data[i], out->linesize[i],
               inpicref->linesize[i], n->linesize[i], n->height[i], n, i);
 
     ret = ff_filter_frame(outlink, out);
     if (inpicref != out)
         avfilter_unref_buffer(inpicref);
     return ret;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     NoiseContext *n = ctx->priv;
     int i;
 
     for (i = 0; i < 4; i++)
         av_freep(&n->param[i].noise);
     av_opt_free(n);
 }
 
 static const AVFilterPad noise_inputs[] = {
     {
         .name             = "default",
         .type             = AVMEDIA_TYPE_VIDEO,
         .get_video_buffer = ff_null_get_video_buffer,
         .filter_frame     = filter_frame,
         .config_props     = config_input,
         .min_perms        = AV_PERM_READ,
     },
     { NULL }
 };
 
 static const AVFilterPad noise_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 
 AVFilter avfilter_vf_noise = {
     .name          = "noise",
     .description   = NULL_IF_CONFIG_SMALL("Add noise."),
     .priv_size     = sizeof(NoiseContext),
     .init          = init,
     .uninit        = uninit,
     .query_formats = query_formats,
     .inputs        = noise_inputs,
     .outputs       = noise_outputs,
     .priv_class    = &noise_class,
 };