/*
  * Copyright (c) 2017 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 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 DespillContext {
     const AVClass *class;
 
     int co[4]; /* color offsets rgba */
 
     int alpha;
     int type;
     float spillmix;
     float spillexpand;
     float redscale;
     float greenscale;
     float bluescale;
     float brightness;
 } DespillContext;
 
 static int do_despill_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
 {
     DespillContext *s = ctx->priv;
     AVFrame *frame = arg;
     const int ro = s->co[0], go = s->co[1], bo = s->co[2], ao = s->co[3];
     const int slice_start = (frame->height * jobnr) / nb_jobs;
     const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
     const float brightness = s->brightness;
     const float redscale = s->redscale;
     const float greenscale = s->greenscale;
     const float bluescale = s->bluescale;
     const float spillmix = s->spillmix;
     const float factor = (1.f - spillmix) * (1.f - s->spillexpand);
     float red, green, blue;
     int x, y;
 
     for (y = slice_start; y < slice_end; y++) {
         uint8_t *dst = frame->data[0] + y * frame->linesize[0];
 
         for (x = 0; x < frame->width; x++) {
             float spillmap;
 
             red   = dst[x * 4 + ro] / 255.f;
             green = dst[x * 4 + go] / 255.f;
             blue  = dst[x * 4 + bo] / 255.f;
 
             if (s->type) {
                 spillmap = FFMAX(blue  - (red * spillmix + green * factor), 0.f);
             } else {
                 spillmap = FFMAX(green - (red * spillmix + blue  * factor), 0.f);
             }
 
             red   = FFMAX(red   + spillmap * redscale   + brightness * spillmap, 0.f);
             green = FFMAX(green + spillmap * greenscale + brightness * spillmap, 0.f);
             blue  = FFMAX(blue  + spillmap * bluescale  + brightness * spillmap, 0.f);
 
             dst[x * 4 + ro] = av_clip_uint8(red   * 255);
             dst[x * 4 + go] = av_clip_uint8(green * 255);
             dst[x * 4 + bo] = av_clip_uint8(blue  * 255);
             if (s->alpha) {
                 spillmap = 1.f - spillmap;
                 dst[x * 4 + ao] = av_clip_uint8(spillmap * 255);
             }
         }
     }
 
     return 0;
 }
 
 static int filter_frame(AVFilterLink *link, AVFrame *frame)
 {
     AVFilterContext *ctx = link->dst;
     int ret;
 
     if (ret = av_frame_make_writable(frame))
         return ret;
 
     if (ret = ctx->internal->execute(ctx, do_despill_slice, frame, NULL, FFMIN(frame->height, ff_filter_get_nb_threads(ctx))))
         return ret;
 
     return ff_filter_frame(ctx->outputs[0], frame);
 }
 
 static av_cold int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     DespillContext *s = ctx->priv;
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(outlink->format);
     int i;
 
     for (i = 0; i < 4; ++i)
         s->co[i] = desc->comp[i].offset;
 
     return 0;
 }
 
 static av_cold int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pixel_fmts[] = {
         AV_PIX_FMT_ARGB,
         AV_PIX_FMT_RGBA,
         AV_PIX_FMT_ABGR,
         AV_PIX_FMT_BGRA,
         AV_PIX_FMT_NONE
     };
     AVFilterFormats *formats = NULL;
 
     formats = ff_make_format_list(pixel_fmts);
     if (!formats)
         return AVERROR(ENOMEM);
 
     return ff_set_common_formats(ctx, formats);
 }
 
 static const AVFilterPad despill_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad despill_outputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .config_props = config_output,
     },
     { NULL }
 };
 
 #define OFFSET(x) offsetof(DespillContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 
 static const AVOption despill_options[] = {
     { "type",       "set the screen type",     OFFSET(type),        AV_OPT_TYPE_INT,     {.i64=0},     0,   1, FLAGS, "type" },
     {   "green",    "greenscreen",             0,                   AV_OPT_TYPE_CONST,   {.i64=0},     0,   0, FLAGS, "type" },
     {   "blue",     "bluescreen",              0,                   AV_OPT_TYPE_CONST,   {.i64=1},     0,   0, FLAGS, "type" },
     { "mix",        "set the spillmap mix",    OFFSET(spillmix),    AV_OPT_TYPE_FLOAT,   {.dbl=0.5},   0,   1, FLAGS },
     { "expand",     "set the spillmap expand", OFFSET(spillexpand), AV_OPT_TYPE_FLOAT,   {.dbl=0},     0,   1, FLAGS },

     { "red",        "set red scale",           OFFSET(redscale),    AV_OPT_TYPE_FLOAT,   {.dbl=0},  -100, 100, FLAGS },

     { "green",      "set green scale",         OFFSET(greenscale),  AV_OPT_TYPE_FLOAT,   {.dbl=-1}, -100, 100, FLAGS },
     { "blue",       "set blue scale",          OFFSET(bluescale),   AV_OPT_TYPE_FLOAT,   {.dbl=0},  -100, 100, FLAGS },
     { "brightness", "set brightness",          OFFSET(brightness),  AV_OPT_TYPE_FLOAT,   {.dbl=0},   -10,  10, FLAGS },
     { "alpha",      "change alpha component",  OFFSET(alpha),       AV_OPT_TYPE_BOOL,    {.i64=0},     0,   1, FLAGS },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(despill);
 
 AVFilter ff_vf_despill = {
     .name          = "despill",
     .description   = NULL_IF_CONFIG_SMALL("Despill video."),
     .priv_size     = sizeof(DespillContext),
     .priv_class    = &despill_class,
     .query_formats = query_formats,
     .inputs        = despill_inputs,
     .outputs       = despill_outputs,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
 };