/*
  * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
  * Copyright (c) 2012 Jeremy Tran
  *
  * 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
  * Apply a smartblur filter to the input video
  * Ported from MPlayer libmpcodecs/vf_smartblur.c by Michael Niedermayer.
  */
 
 #include "libavutil/pixdesc.h"
 #include "libswscale/swscale.h"
 
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 
 #define RADIUS_MIN 0.1
 #define RADIUS_MAX 5.0
 
 #define STRENGTH_MIN -1.0
 #define STRENGTH_MAX 1.0
 
 #define THRESHOLD_MIN -30
 #define THRESHOLD_MAX 30
 
 typedef struct {
     float              radius;
     float              strength;
     int                threshold;
     float              quality;
     struct SwsContext *filter_context;
 } FilterParam;
 
 typedef struct {
     FilterParam  luma;
     FilterParam  chroma;
     int          hsub;
     int          vsub;
     unsigned int sws_flags;
 } SmartblurContext;
 
 #define CHECK_PARAM(param, name, min, max, format, ret)                       \
     if (param < min || param > max) {                                         \
         av_log(ctx, AV_LOG_ERROR,                                             \
                "Invalid " #name " value " #format ": "                        \
                "must be included between range " #format " and " #format "\n",\
                param, min, max);                                              \
         ret = AVERROR(EINVAL);                                                \
     }
 
 static av_cold int init(AVFilterContext *ctx, const char *args)
 {
     SmartblurContext *sblur = ctx->priv;
     int n = 0, ret = 0;
     float lradius, lstrength, cradius, cstrength;
     int lthreshold, cthreshold;
 
     if (args)
         n = sscanf(args, "%f:%f:%d:%f:%f:%d",
                    &lradius, &lstrength, &lthreshold,
                    &cradius, &cstrength, &cthreshold);
 
     if (n != 3 && n != 6) {
         av_log(ctx, AV_LOG_ERROR,
                "Incorrect number of parameters or invalid syntax: "
                "must be luma_radius:luma_strength:luma_threshold"
                "[:chroma_radius:chroma_strength:chroma_threshold]\n");
         return AVERROR(EINVAL);
     }
 
     sblur->luma.radius    = lradius;
     sblur->luma.strength  = lstrength;
     sblur->luma.threshold = lthreshold;
 
     if (n == 3) {
         sblur->chroma.radius    = sblur->luma.radius;
         sblur->chroma.strength  = sblur->luma.strength;
         sblur->chroma.threshold = sblur->luma.threshold;
     } else {
         sblur->chroma.radius    = cradius;
         sblur->chroma.strength  = cstrength;
         sblur->chroma.threshold = cthreshold;
     }
 
     sblur->luma.quality = sblur->chroma.quality = 3.0;
     sblur->sws_flags = SWS_BICUBIC;
 
     CHECK_PARAM(lradius,    luma radius,    RADIUS_MIN,    RADIUS_MAX,    %0.1f, ret)
     CHECK_PARAM(lstrength,  luma strength,  STRENGTH_MIN,  STRENGTH_MAX,  %0.1f, ret)
     CHECK_PARAM(lthreshold, luma threshold, THRESHOLD_MIN, THRESHOLD_MAX, %d,    ret)
 
     if (n != 3) {
         CHECK_PARAM(sblur->chroma.radius,    chroma radius,    RADIUS_MIN,   RADIUS_MAX,    %0.1f, ret)
         CHECK_PARAM(sblur->chroma.strength,  chroma strength,  STRENGTH_MIN, STRENGTH_MAX,  %0.1f, ret)
         CHECK_PARAM(sblur->chroma.threshold, chroma threshold, THRESHOLD_MIN,THRESHOLD_MAX, %d,    ret)
     }
 
     return ret;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     SmartblurContext *sblur = ctx->priv;
 
     sws_freeContext(sblur->luma.filter_context);
     sws_freeContext(sblur->chroma.filter_context);
 }
 
 static int query_formats(AVFilterContext *ctx)
 {

     static const enum AVPixelFormat pix_fmts[] = {
         AV_PIX_FMT_YUV444P,      AV_PIX_FMT_YUV422P,
         AV_PIX_FMT_YUV420P,      AV_PIX_FMT_YUV411P,
         AV_PIX_FMT_YUV410P,      AV_PIX_FMT_YUV440P,
         AV_PIX_FMT_GRAY8,
         AV_PIX_FMT_NONE

     };
 
     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
 
     return 0;
 }
 
 static int alloc_sws_context(FilterParam *f, int width, int height, unsigned int flags)
 {
     SwsVector *vec;
     SwsFilter sws_filter;
 
     vec = sws_getGaussianVec(f->radius, f->quality);
 
     if (!vec)
         return AVERROR(EINVAL);
 
     sws_scaleVec(vec, f->strength);
     vec->coeff[vec->length / 2] += 1.0 - f->strength;
     sws_filter.lumH = sws_filter.lumV = vec;
     sws_filter.chrH = sws_filter.chrV = NULL;
     f->filter_context = sws_getCachedContext(NULL,

                                              width, height, AV_PIX_FMT_GRAY8,
                                              width, height, AV_PIX_FMT_GRAY8,

                                              flags, &sws_filter, NULL, NULL);
 
     sws_freeVec(vec);
 
     if (!f->filter_context)
         return AVERROR(EINVAL);
 
     return 0;
 }
 
 static int config_props(AVFilterLink *inlink)
 {
     SmartblurContext *sblur = inlink->dst->priv;

     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);

 
     sblur->hsub = desc->log2_chroma_w;
     sblur->vsub = desc->log2_chroma_h;
 
     alloc_sws_context(&sblur->luma, inlink->w, inlink->h, sblur->sws_flags);
     alloc_sws_context(&sblur->chroma,
                       inlink->w >> sblur->hsub, inlink->h >> sblur->vsub,
                       sblur->sws_flags);
 
     return 0;
 }
 
 static void blur(uint8_t       *dst, const int dst_linesize,
                  const uint8_t *src, const int src_linesize,
                  const int w, const int h, const int threshold,
                  struct SwsContext *filter_context)
 {
     int x, y;
     int orig, filtered;
     int diff;
     /* Declare arrays of 4 to get aligned data */
     const uint8_t* const src_array[4] = {src};
     uint8_t *dst_array[4]             = {dst};
     int src_linesize_array[4] = {src_linesize};
     int dst_linesize_array[4] = {dst_linesize};
 
     sws_scale(filter_context, src_array, src_linesize_array,
               0, h, dst_array, dst_linesize_array);
 
     if (threshold > 0) {
         for (y = 0; y < h; ++y) {
             for (x = 0; x < w; ++x) {
                 orig     = src[x + y * src_linesize];
                 filtered = dst[x + y * dst_linesize];
                 diff     = orig - filtered;
 
                 if (diff > 0) {
                     if (diff > 2 * threshold)
                         dst[x + y * dst_linesize] = orig;
                     else if (diff > threshold)
                         /* add 'diff' and substract 'threshold' from 'filtered' */
                         dst[x + y * dst_linesize] = orig - threshold;
                 } else {
                     if (-diff > 2 * threshold)
                         dst[x + y * dst_linesize] = orig;
                     else if (-diff > threshold)
                         /* add 'diff' and 'threshold' to 'filtered' */
                         dst[x + y * dst_linesize] = orig + threshold;
                 }
             }
         }
     } else if (threshold < 0) {
         for (y = 0; y < h; ++y) {
             for (x = 0; x < w; ++x) {
                 orig     = src[x + y * src_linesize];
                 filtered = dst[x + y * dst_linesize];
                 diff     = orig - filtered;
 
                 if (diff > 0) {
                     if (diff <= -threshold)
                         dst[x + y * dst_linesize] = orig;
                     else if (diff <= -2 * threshold)
                         /* substract 'diff' and 'threshold' from 'orig' */
                         dst[x + y * dst_linesize] = filtered - threshold;
                 } else {
                     if (diff >= threshold)
                         dst[x + y * dst_linesize] = orig;
                     else if (diff >= 2 * threshold)
                         /* add 'threshold' and substract 'diff' from 'orig' */
                         dst[x + y * dst_linesize] = filtered + threshold;
                 }
             }
         }
     }
 }
 

 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *inpic)

 {
     SmartblurContext  *sblur  = inlink->dst->priv;

     AVFilterLink *outlink     = inlink->dst->outputs[0];

     AVFilterBufferRef *outpic;

     int cw = inlink->w >> sblur->hsub;
     int ch = inlink->h >> sblur->vsub;
 

     outpic = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
     if (!outpic) {
         avfilter_unref_bufferp(&inpic);
         return AVERROR(ENOMEM);
     }
     avfilter_copy_buffer_ref_props(outpic, inpic);
 

     blur(outpic->data[0], outpic->linesize[0],
          inpic->data[0],  inpic->linesize[0],
          inlink->w, inlink->h, sblur->luma.threshold,
          sblur->luma.filter_context);
 
     if (inpic->data[2]) {
         blur(outpic->data[1], outpic->linesize[1],
              inpic->data[1],  inpic->linesize[1],
              cw, ch, sblur->chroma.threshold,
              sblur->chroma.filter_context);
         blur(outpic->data[2], outpic->linesize[2],
              inpic->data[2],  inpic->linesize[2],
              cw, ch, sblur->chroma.threshold,
              sblur->chroma.filter_context);
     }
 

     avfilter_unref_bufferp(&inpic);
     return ff_filter_frame(outlink, outpic);

 }
 

 static const AVFilterPad smartblur_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,

         .filter_frame = filter_frame,

         .config_props = config_props,
         .min_perms    = AV_PERM_READ,
     },
     { NULL }
 };
 
 static const AVFilterPad smartblur_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 

 AVFilter avfilter_vf_smartblur = {
     .name        = "smartblur",
     .description = NULL_IF_CONFIG_SMALL("Blur the input video without impacting the outlines."),
 
     .priv_size = sizeof(SmartblurContext),
 
     .init          = init,
     .uninit        = uninit,
     .query_formats = query_formats,

     .inputs        = smartblur_inputs,
     .outputs       = smartblur_outputs,

 };