/*
  * Copyright (c) 2015 Timo Rothenpieler <timo@rothenpieler.org>
  *
  * 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 "libavutil/imgutils.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
 typedef struct ChromakeyContext {
     const AVClass *class;
 
     uint8_t chromakey_rgba[4];
     uint8_t chromakey_uv[2];
 
     float similarity;
     float blend;
 
     int is_yuv;

 
     int hsub_log2;
     int vsub_log2;

 
     int (*do_slice)(AVFilterContext *ctx, void *arg,
                     int jobnr, int nb_jobs);

 } ChromakeyContext;
 
 static uint8_t do_chromakey_pixel(ChromakeyContext *ctx, uint8_t u[9], uint8_t v[9])
 {
     double diff = 0.0;
     int du, dv, i;
 
     for (i = 0; i < 9; ++i) {
         du = (int)u[i] - ctx->chromakey_uv[0];
         dv = (int)v[i] - ctx->chromakey_uv[1];
 
         diff += sqrt((du * du + dv * dv) / (255.0 * 255.0));
     }
 
     diff /= 9.0;
 
     if (ctx->blend > 0.0001) {
         return av_clipd((diff - ctx->similarity) / ctx->blend, 0.0, 1.0) * 255.0;
     } else {
         return (diff > ctx->similarity) ? 255 : 0;
     }
 }
 
 static av_always_inline void get_pixel_uv(AVFrame *frame, int hsub_log2, int vsub_log2, int x, int y, uint8_t *u, uint8_t *v)
 {
     if (x < 0 || x >= frame->width || y < 0 || y >= frame->height)
         return;
 
     x >>= hsub_log2;
     y >>= vsub_log2;
 
     *u = frame->data[1][frame->linesize[1] * y + x];
     *v = frame->data[2][frame->linesize[2] * y + x];
 }
 
 static int do_chromakey_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
 {
     AVFrame *frame = arg;
 
     const int slice_start = (frame->height * jobnr) / nb_jobs;
     const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
 
     ChromakeyContext *ctx = avctx->priv;
 
     int x, y, xo, yo;
     uint8_t u[9], v[9];
 
     memset(u, ctx->chromakey_uv[0], sizeof(u));
     memset(v, ctx->chromakey_uv[1], sizeof(v));
 
     for (y = slice_start; y < slice_end; ++y) {
         for (x = 0; x < frame->width; ++x) {
             for (yo = 0; yo < 3; ++yo) {
                 for (xo = 0; xo < 3; ++xo) {

                     get_pixel_uv(frame, ctx->hsub_log2, ctx->vsub_log2, x + xo - 1, y + yo - 1, &u[yo * 3 + xo], &v[yo * 3 + xo]);

                 }
             }
 
             frame->data[3][frame->linesize[3] * y + x] = do_chromakey_pixel(ctx, u, v);
         }
     }
 
     return 0;
 }
 

 static int do_chromahold_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
 {
     ChromakeyContext *ctx = avctx->priv;
     AVFrame *frame = arg;
     const int slice_start = ((frame->height >> ctx->vsub_log2) * jobnr) / nb_jobs;
     const int slice_end = ((frame->height >> ctx->vsub_log2) * (jobnr + 1)) / nb_jobs;
 
     int x, y, alpha;
 
     for (y = slice_start; y < slice_end; ++y) {
         for (x = 0; x < frame->width >> ctx->hsub_log2; ++x) {
             int u = frame->data[1][frame->linesize[1] * y + x];
             int v = frame->data[2][frame->linesize[2] * y + x];
             double diff;
             int du, dv;
 
             du = u - ctx->chromakey_uv[0];
             dv = v - ctx->chromakey_uv[1];
 
             diff = sqrt((du * du + dv * dv) / (255.0 * 255.0));
 
             alpha = diff > ctx->similarity;
             if (alpha) {
                 frame->data[1][frame->linesize[1] * y + x] = 128;
                 frame->data[2][frame->linesize[2] * y + x] = 128;
             }
         }
     }
 
     return 0;
 }
 

 static int filter_frame(AVFilterLink *link, AVFrame *frame)
 {
     AVFilterContext *avctx = link->dst;

     ChromakeyContext *ctx = avctx->priv;

     int res;
 

     if (res = avctx->internal->execute(avctx, ctx->do_slice, frame, NULL, FFMIN(frame->height, ff_filter_get_nb_threads(avctx))))

         return res;
 
     return ff_filter_frame(avctx->outputs[0], frame);
 }
 
 #define FIXNUM(x) lrint((x) * (1 << 10))
 #define RGB_TO_U(rgb) (((- FIXNUM(0.16874) * rgb[0] - FIXNUM(0.33126) * rgb[1] + FIXNUM(0.50000) * rgb[2] + (1 << 9) - 1) >> 10) + 128)
 #define RGB_TO_V(rgb) (((  FIXNUM(0.50000) * rgb[0] - FIXNUM(0.41869) * rgb[1] - FIXNUM(0.08131) * rgb[2] + (1 << 9) - 1) >> 10) + 128)
 
 static av_cold int initialize_chromakey(AVFilterContext *avctx)
 {
     ChromakeyContext *ctx = avctx->priv;
 
     if (ctx->is_yuv) {
         ctx->chromakey_uv[0] = ctx->chromakey_rgba[1];
         ctx->chromakey_uv[1] = ctx->chromakey_rgba[2];
     } else {
         ctx->chromakey_uv[0] = RGB_TO_U(ctx->chromakey_rgba);
         ctx->chromakey_uv[1] = RGB_TO_V(ctx->chromakey_rgba);
     }
 

     if (!strcmp(avctx->filter->name, "chromakey")) {
         ctx->do_slice = do_chromakey_slice;
     } else {
         ctx->do_slice = do_chromahold_slice;
     }
 

     return 0;
 }
 
 static av_cold int query_formats(AVFilterContext *avctx)
 {
     static const enum AVPixelFormat pixel_fmts[] = {
         AV_PIX_FMT_YUVA420P,
         AV_PIX_FMT_YUVA422P,
         AV_PIX_FMT_YUVA444P,
         AV_PIX_FMT_NONE
     };
 

     static const enum AVPixelFormat hold_pixel_fmts[] = {
         AV_PIX_FMT_YUV420P,
         AV_PIX_FMT_YUV422P,
         AV_PIX_FMT_YUV444P,
         AV_PIX_FMT_YUVA420P,
         AV_PIX_FMT_YUVA422P,
         AV_PIX_FMT_YUVA444P,
         AV_PIX_FMT_NONE
     };
 

     AVFilterFormats *formats = NULL;
 

     formats = ff_make_format_list(!strcmp(avctx->filter->name, "chromahold") ? hold_pixel_fmts : pixel_fmts);

     if (!formats)
         return AVERROR(ENOMEM);
 
     return ff_set_common_formats(avctx, formats);
 }
 

 static av_cold int config_input(AVFilterLink *inlink)
 {
     AVFilterContext *avctx = inlink->dst;
     ChromakeyContext *ctx = avctx->priv;
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
 
     ctx->hsub_log2 = desc->log2_chroma_w;
     ctx->vsub_log2 = desc->log2_chroma_h;
 
     return 0;
 }
 

 static const AVFilterPad chromakey_inputs[] = {
     {
         .name           = "default",
         .type           = AVMEDIA_TYPE_VIDEO,
         .needs_writable = 1,
         .filter_frame   = filter_frame,

         .config_props   = config_input,

     },
     { NULL }
 };
 
 static const AVFilterPad chromakey_outputs[] = {
     {
         .name           = "default",
         .type           = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 
 #define OFFSET(x) offsetof(ChromakeyContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 
 static const AVOption chromakey_options[] = {
     { "color", "set the chromakey key color", OFFSET(chromakey_rgba), AV_OPT_TYPE_COLOR, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
     { "similarity", "set the chromakey similarity value", OFFSET(similarity), AV_OPT_TYPE_FLOAT, { .dbl = 0.01 }, 0.01, 1.0, FLAGS },
     { "blend", "set the chromakey key blend value", OFFSET(blend), AV_OPT_TYPE_FLOAT, { .dbl = 0.0 }, 0.0, 1.0, FLAGS },
     { "yuv", "color parameter is in yuv instead of rgb", OFFSET(is_yuv), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(chromakey);
 
 AVFilter ff_vf_chromakey = {
     .name          = "chromakey",
     .description   = NULL_IF_CONFIG_SMALL("Turns a certain color into transparency. Operates on YUV colors."),
     .priv_size     = sizeof(ChromakeyContext),
     .priv_class    = &chromakey_class,
     .init          = initialize_chromakey,
     .query_formats = query_formats,
     .inputs        = chromakey_inputs,
     .outputs       = chromakey_outputs,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
 };

 
 static const AVOption chromahold_options[] = {
     { "color", "set the chromahold key color", OFFSET(chromakey_rgba), AV_OPT_TYPE_COLOR, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
     { "similarity", "set the chromahold similarity value", OFFSET(similarity), AV_OPT_TYPE_FLOAT, { .dbl = 0.01 }, 0.01, 1.0, FLAGS },
     { "yuv", "color parameter is in yuv instead of rgb", OFFSET(is_yuv), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },
     { NULL }
 };
 
 static const AVFilterPad chromahold_inputs[] = {
     {
         .name           = "default",
         .type           = AVMEDIA_TYPE_VIDEO,
         .needs_writable = 1,
         .filter_frame   = filter_frame,
         .config_props   = config_input,
     },
     { NULL }
 };
 
 static const AVFilterPad chromahold_outputs[] = {
     {
         .name           = "default",
         .type           = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(chromahold);
 
 AVFilter ff_vf_chromahold = {
     .name          = "chromahold",
     .description   = NULL_IF_CONFIG_SMALL("Turns a certain color range into gray."),
     .priv_size     = sizeof(ChromakeyContext),
     .priv_class    = &chromahold_class,
     .init          = initialize_chromakey,
     .query_formats = query_formats,
     .inputs        = chromahold_inputs,
     .outputs       = chromahold_outputs,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
 };