/*
  * Copyright (c) 2019 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/avstring.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 #include "libavutil/qsort.h"
 
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 #include "framesync.h"
 #include "video.h"
 
 typedef struct XMedianContext {
     const AVClass *class;
     const AVPixFmtDescriptor *desc;
     int nb_inputs;

     int nb_frames;

     int planes;

     float percentile;

     int tmedian;

     int radius;

     int index;

     int depth;
     int max;
     int nb_planes;
     int linesize[4];
     int width[4];
     int height[4];
 
     AVFrame **frames;
     FFFrameSync fs;
 
     int (*median_frames)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
 } XMedianContext;
 
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pixel_fmts[] = {
         AV_PIX_FMT_GRAY8,
         AV_PIX_FMT_GRAY9,
         AV_PIX_FMT_GRAY10,
         AV_PIX_FMT_GRAY12,
         AV_PIX_FMT_GRAY14,
         AV_PIX_FMT_GRAY16,
         AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
         AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
         AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
         AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
         AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P,
         AV_PIX_FMT_YUVJ411P,
         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_YUV440P10,
         AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV420P12,
         AV_PIX_FMT_YUV440P12,
         AV_PIX_FMT_YUV444P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV420P14,
         AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
         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_YUVA420P,  AV_PIX_FMT_YUVA422P,   AV_PIX_FMT_YUVA444P,
         AV_PIX_FMT_YUVA444P9, AV_PIX_FMT_YUVA444P10, AV_PIX_FMT_YUVA444P12, AV_PIX_FMT_YUVA444P16,
         AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA422P12, AV_PIX_FMT_YUVA422P16,
         AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA420P16,
         AV_PIX_FMT_GBRAP,     AV_PIX_FMT_GBRAP10,    AV_PIX_FMT_GBRAP12,    AV_PIX_FMT_GBRAP16,

         AV_PIX_FMT_NONE
     };
     AVFilterFormats *formats = ff_make_format_list(pixel_fmts);
     if (!formats)
         return AVERROR(ENOMEM);
     return ff_set_common_formats(ctx, formats);
 }
 
 static av_cold int init(AVFilterContext *ctx)
 {
     XMedianContext *s = ctx->priv;
     int ret;
 

     s->tmedian = !strcmp(ctx->filter->name, "tmedian");
 
     if (!s->tmedian) {
         s->radius = s->nb_inputs / 2;
     } else {
         s->nb_inputs = s->radius * 2 + 1;
     }
 

     if (s->nb_inputs & 1)
         s->index = s->radius * 2.f * s->percentile;
     else
         s->index = av_clip(s->radius * 2.f * s->percentile, 1, s->nb_inputs - 1);

     s->frames = av_calloc(s->nb_inputs, sizeof(*s->frames));
     if (!s->frames)
         return AVERROR(ENOMEM);
 

     for (int i = 0; i < s->nb_inputs && !s->tmedian; i++) {

         AVFilterPad pad = { 0 };
 
         pad.type = AVMEDIA_TYPE_VIDEO;
         pad.name = av_asprintf("input%d", i);
         if (!pad.name)
             return AVERROR(ENOMEM);
 
         if ((ret = ff_insert_inpad(ctx, i, &pad)) < 0) {
             av_freep(&pad.name);
             return ret;
         }
     }
 
     return 0;
 }
 
 typedef struct ThreadData {
     AVFrame **in, *out;
 } ThreadData;
 
 static int comparei(const void *p1, const void *p2)
 {
     int left  = *(const int *)p1;
     int right = *(const int *)p2;
     return FFDIFFSIGN(left, right);
 }
 
 static int median_frames16(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
 {
     XMedianContext *s = ctx->priv;
     ThreadData *td = arg;
     AVFrame **in = td->in;
     AVFrame *out = td->out;
     const int nb_inputs = s->nb_inputs;
     const int radius = s->radius;

     const int index = s->index;

     int values[256];
 
     for (int p = 0; p < s->nb_planes; p++) {
         const int slice_start = (s->height[p] * jobnr) / nb_jobs;
         const int slice_end = (s->height[p] * (jobnr+1)) / nb_jobs;
         uint16_t *dst = (uint16_t *)(out->data[p] + slice_start * out->linesize[p]);
 
         if (!((1 << p) & s->planes)) {
             av_image_copy_plane((uint8_t *)dst, out->linesize[p],

                                 in[radius]->data[p] + slice_start * in[radius]->linesize[p],
                                 in[radius]->linesize[p],

                                 s->linesize[p], slice_end - slice_start);
             continue;
         }
 
         for (int y = slice_start; y < slice_end; y++) {
             for (int x = 0; x < s->width[p]; x++) {
                 for (int i = 0; i < nb_inputs; i++) {
                     const uint16_t *src = (const uint16_t *)(in[i]->data[p] + y * in[i]->linesize[p]);
                     values[i] = src[x];
                 }
 
                 AV_QSORT(values, nb_inputs, int, comparei);

                 if (nb_inputs & 1)
                     dst[x] = values[index];

                 else

                     dst[x] = (values[index] + values[index - 1]) >> 1;

             }
 
             dst += out->linesize[p] / 2;
         }
     }
 
     return 0;
 }
 
 static int median_frames8(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
 {
     XMedianContext *s = ctx->priv;
     ThreadData *td = arg;
     AVFrame **in = td->in;
     AVFrame *out = td->out;
     const int nb_inputs = s->nb_inputs;
     const int radius = s->radius;

     const int index = s->index;

     int values[256];
 
     for (int p = 0; p < s->nb_planes; p++) {
         const int slice_start = (s->height[p] * jobnr) / nb_jobs;
         const int slice_end = (s->height[p] * (jobnr+1)) / nb_jobs;
         uint8_t *dst = out->data[p] + slice_start * out->linesize[p];
 
         if (!((1 << p) & s->planes)) {
             av_image_copy_plane(dst, out->linesize[p],

                                 in[radius]->data[p] + slice_start * in[radius]->linesize[p],
                                 in[radius]->linesize[p],

                                 s->linesize[p], slice_end - slice_start);
             continue;
         }
 
         for (int y = slice_start; y < slice_end; y++) {
             for (int x = 0; x < s->width[p]; x++) {
                 for (int i = 0; i < nb_inputs; i++)
                     values[i] = in[i]->data[p][y * in[i]->linesize[p] + x];
 
                 AV_QSORT(values, nb_inputs, int, comparei);

                 if (nb_inputs & 1)
                     dst[x] = values[index];

                 else

                     dst[x] = (values[index] + values[index - 1]) >> 1;

             }
 
             dst += out->linesize[p];
         }
     }
 
     return 0;
 }
 
 static int process_frame(FFFrameSync *fs)
 {
     AVFilterContext *ctx = fs->parent;
     AVFilterLink *outlink = ctx->outputs[0];
     XMedianContext *s = fs->opaque;
     AVFrame **in = s->frames;
     AVFrame *out;
     ThreadData td;
     int i, ret;
 
     for (i = 0; i < s->nb_inputs; i++) {
         if ((ret = ff_framesync_get_frame(&s->fs, i, &in[i], 0)) < 0)
             return ret;
     }
 
     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
     if (!out)
         return AVERROR(ENOMEM);
     out->pts = av_rescale_q(s->fs.pts, s->fs.time_base, outlink->time_base);
 
     td.in = in;
     td.out = out;
     ctx->internal->execute(ctx, s->median_frames, &td, NULL, FFMIN(s->height[1], ff_filter_get_nb_threads(ctx)));
 
     return ff_filter_frame(outlink, out);
 }
 
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     XMedianContext *s = ctx->priv;
     AVRational frame_rate = ctx->inputs[0]->frame_rate;

     AVRational sar = ctx->inputs[0]->sample_aspect_ratio;

     AVFilterLink *inlink = ctx->inputs[0];
     int height = ctx->inputs[0]->h;
     int width = ctx->inputs[0]->w;
     FFFrameSyncIn *in;
     int i, ret;
 

     for (int i = 1; i < s->nb_inputs && !s->tmedian; i++) {

         if (ctx->inputs[i]->h != height || ctx->inputs[i]->w != width) {
             av_log(ctx, AV_LOG_ERROR, "Input %d size (%dx%d) does not match input %d size (%dx%d).\n", i, ctx->inputs[i]->w, ctx->inputs[i]->h, 0, width, height);
             return AVERROR(EINVAL);
         }
     }
 
     s->desc = av_pix_fmt_desc_get(outlink->format);
     if (!s->desc)
         return AVERROR_BUG;
     s->nb_planes = av_pix_fmt_count_planes(outlink->format);
     s->depth = s->desc->comp[0].depth;
     s->max = (1 << s->depth) - 1;
 
     if (s->depth <= 8)
         s->median_frames = median_frames8;
     else
         s->median_frames = median_frames16;
 
     if ((ret = av_image_fill_linesizes(s->linesize, inlink->format, inlink->w)) < 0)
         return ret;
 
     s->width[1] = s->width[2] = AV_CEIL_RSHIFT(inlink->w, s->desc->log2_chroma_w);
     s->width[0] = s->width[3] = inlink->w;
     s->height[1] = s->height[2] = AV_CEIL_RSHIFT(inlink->h, s->desc->log2_chroma_h);
     s->height[0] = s->height[3] = inlink->h;
 

     if (s->tmedian)
         return 0;
 

     outlink->w          = width;
     outlink->h          = height;
     outlink->frame_rate = frame_rate;

     outlink->sample_aspect_ratio = sar;

 
     if ((ret = ff_framesync_init(&s->fs, ctx, s->nb_inputs)) < 0)
         return ret;
 
     in = s->fs.in;
     s->fs.opaque = s;
     s->fs.on_event = process_frame;
 
     for (i = 0; i < s->nb_inputs; i++) {
         AVFilterLink *inlink = ctx->inputs[i];
 
         in[i].time_base = inlink->time_base;
         in[i].sync   = 1;
         in[i].before = EXT_STOP;
         in[i].after  = EXT_STOP;
     }
 
     ret = ff_framesync_configure(&s->fs);
     outlink->time_base = s->fs.time_base;
 
     return ret;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     XMedianContext *s = ctx->priv;
 
     ff_framesync_uninit(&s->fs);
 

     for (int i = 0; i < ctx->nb_inputs && !s->tmedian; i++)

         av_freep(&ctx->input_pads[i].name);

     for (int i = 0; i < s->nb_frames && s->frames && s->tmedian; i++)
         av_frame_free(&s->frames[i]);
     av_freep(&s->frames);

 }
 
 static int activate(AVFilterContext *ctx)
 {
     XMedianContext *s = ctx->priv;
     return ff_framesync_activate(&s->fs);
 }
 
 #define OFFSET(x) offsetof(XMedianContext, x)
 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
 
 static const AVOption xmedian_options[] = {

     { "inputs", "set number of inputs", OFFSET(nb_inputs), AV_OPT_TYPE_INT, {.i64=3},  3, 255, .flags = FLAGS },
     { "planes", "set planes to filter", OFFSET(planes),    AV_OPT_TYPE_INT, {.i64=15}, 0,  15, .flags = FLAGS },

     { "percentile", "set percentile",   OFFSET(percentile),AV_OPT_TYPE_FLOAT,{.dbl=0.5}, 0, 1, .flags = FLAGS },

     { NULL },
 };
 
 static const AVFilterPad outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .config_props  = config_output,
     },
     { NULL }
 };
 

 #if CONFIG_XMEDIAN_FILTER

 AVFILTER_DEFINE_CLASS(xmedian);
 
 AVFilter ff_vf_xmedian = {
     .name          = "xmedian",
     .description   = NULL_IF_CONFIG_SMALL("Pick median pixels from several video inputs."),
     .priv_size     = sizeof(XMedianContext),
     .priv_class    = &xmedian_class,
     .query_formats = query_formats,
     .outputs       = outputs,
     .init          = init,
     .uninit        = uninit,
     .activate      = activate,
     .flags         = AVFILTER_FLAG_DYNAMIC_INPUTS | AVFILTER_FLAG_SLICE_THREADS,
 };

 
 #endif /* CONFIG_XMEDIAN_FILTER */
 
 #if CONFIG_TMEDIAN_FILTER
 static int tmedian_filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     XMedianContext *s = ctx->priv;
     ThreadData td;
     AVFrame *out;
 
     if (s->nb_frames < s->nb_inputs) {
         s->frames[s->nb_frames] = in;
         s->nb_frames++;
         if (s->nb_frames < s->nb_inputs)
             return 0;
     } else {
         av_frame_free(&s->frames[0]);
         memmove(&s->frames[0], &s->frames[1], sizeof(*s->frames) * (s->nb_inputs - 1));
         s->frames[s->nb_inputs - 1] = in;
     }
 
     if (ctx->is_disabled) {
         out = av_frame_clone(s->frames[0]);
         if (!out)
             return AVERROR(ENOMEM);
         return ff_filter_frame(outlink, out);
     }
 
     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
     if (!out)
         return AVERROR(ENOMEM);
     out->pts = s->frames[0]->pts;
 
     td.out = out;
     td.in = s->frames;
     ctx->internal->execute(ctx, s->median_frames, &td, NULL, FFMIN(s->height[0], ff_filter_get_nb_threads(ctx)));
 
     return ff_filter_frame(outlink, out);
 }
 
 static const AVOption tmedian_options[] = {
     { "radius",     "set median filter radius", OFFSET(radius),     AV_OPT_TYPE_INT,   {.i64=1},   1, 127, .flags = FLAGS },
     { "planes",     "set planes to filter",     OFFSET(planes),     AV_OPT_TYPE_INT,   {.i64=15},  0,  15, .flags = FLAGS },
     { "percentile", "set percentile",           OFFSET(percentile), AV_OPT_TYPE_FLOAT, {.dbl=0.5}, 0,   1, .flags = FLAGS },
     { NULL },
 };
 
 static const AVFilterPad tmedian_inputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .filter_frame  = tmedian_filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad tmedian_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .config_props  = config_output,
     },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(tmedian);
 
 AVFilter ff_vf_tmedian = {
     .name          = "tmedian",
     .description   = NULL_IF_CONFIG_SMALL("Pick median pixels from successive frames."),
     .priv_size     = sizeof(XMedianContext),
     .priv_class    = &tmedian_class,
     .query_formats = query_formats,
     .inputs        = tmedian_inputs,
     .outputs       = tmedian_outputs,
     .init          = init,
     .uninit        = uninit,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL | AVFILTER_FLAG_SLICE_THREADS,
 };
 
 #endif /* CONFIG_TMEDIAN_FILTER */