/*
  * Copyright (c) 2011 Pascal Getreuer
  * Copyright (c) 2016 Paul B Mahol
  *
  * Redistribution and use in source and binary forms, with or without modification,
  * are permitted provided that the following conditions are met:
  *
  *  * Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *  * Redistributions in binary form must reproduce the above
  *    copyright notice, this list of conditions and the following
  *    disclaimer in the documentation and/or other materials provided
  *    with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * HOLDER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "libavutil/imgutils.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
 typedef struct GBlurContext {
     const AVClass *class;
 
     float sigma;

     float sigmaV;

     int steps;
     int planes;
 
     int depth;
     int planewidth[4];
     int planeheight[4];
     float *buffer;
     float boundaryscale;

     float boundaryscaleV;

     float postscale;

     float postscaleV;

     float nu;

     float nuV;

     int nb_planes;
 } GBlurContext;
 
 #define OFFSET(x) offsetof(GBlurContext, x)
 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 
 static const AVOption gblur_options[] = {
     { "sigma",  "set sigma",            OFFSET(sigma),  AV_OPT_TYPE_FLOAT, {.dbl=0.5}, 0.0, 1024, FLAGS },
     { "steps",  "set number of steps",  OFFSET(steps),  AV_OPT_TYPE_INT,   {.i64=1},     1,    6, FLAGS },
     { "planes", "set planes to filter", OFFSET(planes), AV_OPT_TYPE_INT,   {.i64=0xF},   0,  0xF, FLAGS },

     { "sigmaV", "set vertical sigma",   OFFSET(sigmaV), AV_OPT_TYPE_FLOAT, {.dbl=-1},   -1, 1024, FLAGS },

     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(gblur);
 
 typedef struct ThreadData {
     int height;
     int width;
 } ThreadData;
 
 static int filter_horizontally(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
 {
     GBlurContext *s = ctx->priv;
     ThreadData *td = arg;
     const int height = td->height;
     const int width = td->width;
     const int slice_start = (height *  jobnr   ) / nb_jobs;
     const int slice_end   = (height * (jobnr+1)) / nb_jobs;
     const float boundaryscale = s->boundaryscale;
     const int steps = s->steps;
     const float nu = s->nu;
     float *buffer = s->buffer;
     int y, x, step;
     float *ptr;
 
     /* Filter horizontally along each row */
     for (y = slice_start; y < slice_end; y++) {
         for (step = 0; step < steps; step++) {
             ptr = buffer + width * y;
             ptr[0] *= boundaryscale;
 
             /* Filter rightwards */
             for (x = 1; x < width; x++)
                 ptr[x] += nu * ptr[x - 1];
 
             ptr[x = width - 1] *= boundaryscale;
 
             /* Filter leftwards */
             for (; x > 0; x--)
                 ptr[x - 1] += nu * ptr[x];
         }
     }
 
     return 0;
 }
 
 static int filter_vertically(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
 {
     GBlurContext *s = ctx->priv;
     ThreadData *td = arg;
     const int height = td->height;
     const int width = td->width;
     const int slice_start = (width *  jobnr   ) / nb_jobs;
     const int slice_end   = (width * (jobnr+1)) / nb_jobs;

     const float boundaryscale = s->boundaryscaleV;

     const int numpixels = width * height;
     const int steps = s->steps;

     const float nu = s->nuV;

     float *buffer = s->buffer;
     int i, x, step;
     float *ptr;
 
     /* Filter vertically along each column */
     for (x = slice_start; x < slice_end; x++) {
         for (step = 0; step < steps; step++) {
             ptr = buffer + x;
             ptr[0] *= boundaryscale;
 
             /* Filter downwards */
             for (i = width; i < numpixels; i += width)
                 ptr[i] += nu * ptr[i - width];
 
             ptr[i = numpixels - width] *= boundaryscale;
 
             /* Filter upwards */
             for (; i > 0; i -= width)
                 ptr[i - width] += nu * ptr[i];
         }
     }
 
     return 0;
 }
 
 
 static int filter_postscale(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
 {
     GBlurContext *s = ctx->priv;
     ThreadData *td = arg;
     const int height = td->height;
     const int width = td->width;

     const int64_t numpixels = width * (int64_t)height;
     const unsigned slice_start = (numpixels *  jobnr   ) / nb_jobs;
     const unsigned slice_end   = (numpixels * (jobnr+1)) / nb_jobs;

     const float postscale = s->postscale * s->postscaleV;

     float *buffer = s->buffer;

     unsigned i;

 
     for (i = slice_start; i < slice_end; i++)
         buffer[i] *= postscale;
 
     return 0;
 }
 
 static void gaussianiir2d(AVFilterContext *ctx, int plane)
 {
     GBlurContext *s = ctx->priv;
     const int width = s->planewidth[plane];
     const int height = s->planeheight[plane];
     const int nb_threads = ff_filter_get_nb_threads(ctx);
     ThreadData td;
 
     if (s->sigma <= 0 || s->steps < 0)
         return;
 
     td.width = width;
     td.height = height;
     ctx->internal->execute(ctx, filter_horizontally, &td, NULL, FFMIN(height, nb_threads));
     ctx->internal->execute(ctx, filter_vertically, &td, NULL, FFMIN(width, nb_threads));
     ctx->internal->execute(ctx, filter_postscale, &td, NULL, FFMIN(width * height, nb_threads));
 }
 
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pix_fmts[] = {
         AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV440P,
         AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
         AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUV420P,
         AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
         AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
         AV_PIX_FMT_YUV420P9, AV_PIX_FMT_YUV422P9, AV_PIX_FMT_YUV444P9,
         AV_PIX_FMT_YUV420P10, AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV444P10,
         AV_PIX_FMT_YUV420P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV440P12,
         AV_PIX_FMT_YUV420P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV444P14,
         AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
         AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA444P9,
         AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA444P10,
         AV_PIX_FMT_YUVA420P16, AV_PIX_FMT_YUVA422P16, AV_PIX_FMT_YUVA444P16,
         AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRP9, AV_PIX_FMT_GBRP10,
         AV_PIX_FMT_GBRP12, AV_PIX_FMT_GBRP14, AV_PIX_FMT_GBRP16,

         AV_PIX_FMT_GBRAP, AV_PIX_FMT_GBRAP10, AV_PIX_FMT_GBRAP12, AV_PIX_FMT_GBRAP16,
         AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY9, AV_PIX_FMT_GRAY10, AV_PIX_FMT_GRAY12, AV_PIX_FMT_GRAY16,

         AV_PIX_FMT_NONE
     };
 
     return ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
 }
 
 static int config_input(AVFilterLink *inlink)
 {
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
     GBlurContext *s = inlink->dst->priv;
 
     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);
 
     s->buffer = av_malloc_array(inlink->w, inlink->h * sizeof(*s->buffer));
     if (!s->buffer)
         return AVERROR(ENOMEM);

 
     if (s->sigmaV < 0) {
         s->sigmaV = s->sigma;
     }
 

     return 0;
 }
 

 static void set_params(float sigma, int steps, float *postscale, float *boundaryscale, float *nu)
 {
     double dnu, lambda;
 
     lambda = (sigma * sigma) / (2.0 * steps);
     dnu = (1.0 + 2.0 * lambda - sqrt(1.0 + 4.0 * lambda)) / (2.0 * lambda);
     *postscale = pow(dnu / lambda, steps);
     *boundaryscale = 1.0 / (1.0 - dnu);
     *nu = (float)dnu;
 }
 

 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
     GBlurContext *s = ctx->priv;
     AVFilterLink *outlink = ctx->outputs[0];
     AVFrame *out;
     int plane;
 

     set_params(s->sigma,  s->steps, &s->postscale,  &s->boundaryscale,  &s->nu);
     set_params(s->sigmaV, s->steps, &s->postscaleV, &s->boundaryscaleV, &s->nuV);

 
     if (av_frame_is_writable(in)) {
         out = in;
     } else {
         out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
         if (!out) {
             av_frame_free(&in);
             return AVERROR(ENOMEM);
         }
         av_frame_copy_props(out, in);
     }
 
     for (plane = 0; plane < s->nb_planes; plane++) {
         const int height = s->planeheight[plane];
         const int width = s->planewidth[plane];
         float *bptr = s->buffer;
         const uint8_t *src = in->data[plane];
         const uint16_t *src16 = (const uint16_t *)in->data[plane];
         uint8_t *dst = out->data[plane];
         uint16_t *dst16 = (uint16_t *)out->data[plane];
         int y, x;
 
         if (!s->sigma || !(s->planes & (1 << plane))) {
             if (out != in)
                 av_image_copy_plane(out->data[plane], out->linesize[plane],
                                     in->data[plane], in->linesize[plane],
                                     width * ((s->depth + 7) / 8), height);
             continue;
         }
 
         if (s->depth == 8) {
             for (y = 0; y < height; y++) {
                 for (x = 0; x < width; x++) {
                     bptr[x] = src[x];
                 }
                 bptr += width;
                 src += in->linesize[plane];
             }
         } else {
             for (y = 0; y < height; y++) {
                 for (x = 0; x < width; x++) {
                     bptr[x] = src16[x];
                 }
                 bptr += width;
                 src16 += in->linesize[plane] / 2;
             }
         }
 
         gaussianiir2d(ctx, plane);
 
         bptr = s->buffer;
         if (s->depth == 8) {
             for (y = 0; y < height; y++) {
                 for (x = 0; x < width; x++) {
                     dst[x] = bptr[x];
                 }
                 bptr += width;
                 dst += out->linesize[plane];
             }
         } else {
             for (y = 0; y < height; y++) {
                 for (x = 0; x < width; x++) {
                     dst16[x] = bptr[x];
                 }
                 bptr += width;
                 dst16 += out->linesize[plane] / 2;
             }
         }
     }
 
     if (out != in)
         av_frame_free(&in);
     return ff_filter_frame(outlink, out);
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     GBlurContext *s = ctx->priv;
 
     av_freep(&s->buffer);
 }
 
 static const AVFilterPad gblur_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .config_props = config_input,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad gblur_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 
 AVFilter ff_vf_gblur = {
     .name          = "gblur",
     .description   = NULL_IF_CONFIG_SMALL("Apply Gaussian Blur filter."),
     .priv_size     = sizeof(GBlurContext),
     .priv_class    = &gblur_class,
     .uninit        = uninit,
     .query_formats = query_formats,
     .inputs        = gblur_inputs,
     .outputs       = gblur_outputs,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
 };