/*
  * Copyright (c) 2012-2013 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/avassert.h"
 #include "libavutil/opt.h"
 #include "libavutil/parseutils.h"
 #include "libavutil/pixdesc.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
 enum HistogramMode {
     MODE_LEVELS,
     MODE_WAVEFORM,
     MODE_COLOR,
     MODE_COLOR2,
     MODE_NB
 };
 
 typedef struct HistogramContext {
     const AVClass *class;               ///< AVClass context for log and options purpose

     int mode;                           ///< HistogramMode

     unsigned       histogram[256];
     int            ncomp;
     const uint8_t  *bg_color;
     const uint8_t  *fg_color;
     int            level_height;
     int            scale_height;
     int            step;
     int            waveform_mode;

     int            waveform_mirror;

     int            display_mode;

     int            levels_mode;

     const AVPixFmtDescriptor *desc;

 } HistogramContext;
 
 #define OFFSET(x) offsetof(HistogramContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 
 static const AVOption histogram_options[] = {
     { "mode", "set histogram mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=MODE_LEVELS}, 0, MODE_NB-1, FLAGS, "mode"},
     { "levels", "standard histogram", 0, AV_OPT_TYPE_CONST, {.i64=MODE_LEVELS}, 0, 0, FLAGS, "mode" },
     { "waveform", "per row/column luminance graph", 0, AV_OPT_TYPE_CONST, {.i64=MODE_WAVEFORM}, 0, 0, FLAGS, "mode" },
     { "color", "chroma values in vectorscope", 0, AV_OPT_TYPE_CONST, {.i64=MODE_COLOR}, 0, 0, FLAGS, "mode" },
     { "color2", "chroma values in vectorscope", 0, AV_OPT_TYPE_CONST, {.i64=MODE_COLOR2}, 0, 0, FLAGS, "mode" },
     { "level_height", "set level height", OFFSET(level_height), AV_OPT_TYPE_INT, {.i64=200}, 50, 2048, FLAGS},
     { "scale_height", "set scale height", OFFSET(scale_height), AV_OPT_TYPE_INT, {.i64=12}, 0, 40, FLAGS},
     { "step", "set waveform step value", OFFSET(step), AV_OPT_TYPE_INT, {.i64=10}, 1, 255, FLAGS},
     { "waveform_mode", "set waveform mode", OFFSET(waveform_mode), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "waveform_mode"},
     { "row",   NULL, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "waveform_mode" },
     { "column", NULL, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "waveform_mode" },

     { "waveform_mirror", "set waveform mirroring", OFFSET(waveform_mirror), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "waveform_mirror"},

     { "display_mode", "set display mode", OFFSET(display_mode), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS, "display_mode"},
     { "parade",  NULL, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "display_mode" },
     { "overlay", NULL, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "display_mode" },

     { "levels_mode", "set levels mode", OFFSET(levels_mode), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "levels_mode"},
     { "linear",      NULL, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "levels_mode" },
     { "logarithmic", NULL, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "levels_mode" },

     { NULL }

 };
 
 AVFILTER_DEFINE_CLASS(histogram);
 
 static const enum AVPixelFormat color_pix_fmts[] = {
     AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVJ444P,
     AV_PIX_FMT_NONE
 };
 
 static const enum AVPixelFormat levels_pix_fmts[] = {
     AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVJ444P,

     AV_PIX_FMT_GRAY8, AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP, AV_PIX_FMT_NONE

 };
 

 static const enum AVPixelFormat waveform_pix_fmts[] = {
      AV_PIX_FMT_GBRP,     AV_PIX_FMT_GBRAP,
      AV_PIX_FMT_YUV422P,  AV_PIX_FMT_YUV420P,
      AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV440P,
      AV_PIX_FMT_YUV411P,  AV_PIX_FMT_YUV410P,
      AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUVJ420P,
      AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P,
      AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,
      AV_PIX_FMT_GRAY8,
      AV_PIX_FMT_NONE
 };
 

 static int query_formats(AVFilterContext *ctx)
 {
     HistogramContext *h = ctx->priv;
     const enum AVPixelFormat *pix_fmts;

     AVFilterFormats *fmts_list;

 
     switch (h->mode) {

     case MODE_WAVEFORM:

         pix_fmts = waveform_pix_fmts;
         break;

     case MODE_LEVELS:
         pix_fmts = levels_pix_fmts;
         break;
     case MODE_COLOR:
     case MODE_COLOR2:
         pix_fmts = color_pix_fmts;
         break;
     default:
         av_assert0(0);
     }
 

     fmts_list = ff_make_format_list(pix_fmts);
     if (!fmts_list)
         return AVERROR(ENOMEM);
     return ff_set_common_formats(ctx, fmts_list);

 }
 
 static const uint8_t black_yuva_color[4] = { 0, 127, 127, 255 };
 static const uint8_t black_gbrp_color[4] = { 0, 0, 0, 255 };
 static const uint8_t white_yuva_color[4] = { 255, 127, 127, 255 };
 static const uint8_t white_gbrp_color[4] = { 255, 255, 255, 255 };
 
 static int config_input(AVFilterLink *inlink)
 {
     HistogramContext *h = inlink->dst->priv;
 

     h->desc  = av_pix_fmt_desc_get(inlink->format);
     h->ncomp = h->desc->nb_components;

 
     switch (inlink->format) {

     case AV_PIX_FMT_GBRAP:

     case AV_PIX_FMT_GBRP:
         h->bg_color = black_gbrp_color;
         h->fg_color = white_gbrp_color;
         break;
     default:
         h->bg_color = black_yuva_color;
         h->fg_color = white_yuva_color;
     }
 
     return 0;
 }
 
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     HistogramContext *h = ctx->priv;
 
     switch (h->mode) {
     case MODE_LEVELS:
         outlink->w = 256;

         outlink->h = (h->level_height + h->scale_height) * FFMAX(h->ncomp * h->display_mode, 1);

         break;
     case MODE_WAVEFORM:
         if (h->waveform_mode)

             outlink->h = 256 * FFMAX(h->ncomp * h->display_mode, 1);

         else

             outlink->w = 256 * FFMAX(h->ncomp * h->display_mode, 1);

         break;
     case MODE_COLOR:
     case MODE_COLOR2:
         outlink->h = outlink->w = 256;
         break;
     default:
         av_assert0(0);
     }
 
     outlink->sample_aspect_ratio = (AVRational){1,1};
 
     return 0;
 }
 

 static void gen_waveform(HistogramContext *h, AVFrame *inpicref, AVFrame *outpicref,
                          int component, int intensity, int offset, int col_mode)
 {
     const int plane = h->desc->comp[component].plane;

     const int mirror = h->waveform_mirror;

     const int is_chroma = (component == 1 || component == 2);
     const int shift_w = (is_chroma ? h->desc->log2_chroma_w : 0);
     const int shift_h = (is_chroma ? h->desc->log2_chroma_h : 0);

     const int src_linesize = inpicref->linesize[plane];
     const int dst_linesize = outpicref->linesize[plane];

     const int dst_signed_linesize = dst_linesize * (mirror == 1 ? -1 : 1);

     uint8_t *src_data = inpicref->data[plane];

     uint8_t *dst_data = outpicref->data[plane] + (col_mode ? (offset >> shift_h) * dst_linesize : offset >> shift_w);

     uint8_t * const dst_bottom_line = dst_data + dst_linesize * ((256 >> shift_h) - 1);
     uint8_t * const dst_line = (mirror ? dst_bottom_line : dst_data);

     const uint8_t max = 255 - intensity;

     const int src_h = FF_CEIL_RSHIFT(inpicref->height, shift_h);
     const int src_w = FF_CEIL_RSHIFT(inpicref->width, shift_w);

     uint8_t *dst, *p;
     int y;
 

     if (!col_mode && mirror)
         dst_data += 256 >> shift_w;

     for (y = 0; y < src_h; y++) {
         const uint8_t *src_data_end = src_data + src_w;
         dst = dst_line;
         for (p = src_data; p < src_data_end; p++) {
             uint8_t *target;

             if (col_mode) {
                 target = dst++ + dst_signed_linesize * (*p >> shift_h);
             } else {
                 if (mirror)
                     target = dst_data - (*p >> shift_w);
                 else
                     target = dst_data + (*p >> shift_w);
             }

             if (*target <= max)
                 *target += intensity;
             else
                 *target = 255;
         }
         src_data += src_linesize;
         dst_data += dst_linesize;
     }
 }
 
 

 static int filter_frame(AVFilterLink *inlink, AVFrame *in)

 {
     HistogramContext *h   = inlink->dst->priv;
     AVFilterContext *ctx  = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];

     AVFrame *out;

     const uint8_t *src;
     uint8_t *dst;

     int i, j, k, l;

     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);

     if (!out) {

         av_frame_free(&in);

         return AVERROR(ENOMEM);
     }
 
     out->pts = in->pts;
 

     for (k = 0; k < h->ncomp; k++) {

         const int is_chroma = (k == 1 || k == 2);
         const int dst_h = FF_CEIL_RSHIFT(outlink->h, (is_chroma ? h->desc->log2_chroma_h : 0));
         const int dst_w = FF_CEIL_RSHIFT(outlink->w, (is_chroma ? h->desc->log2_chroma_w : 0));

         for (i = 0; i < dst_h ; i++)
             memset(out->data[h->desc->comp[k].plane] +
                    i * out->linesize[h->desc->comp[k].plane],
                    h->bg_color[k], dst_w);
     }

 
     switch (h->mode) {
     case MODE_LEVELS:
         for (k = 0; k < h->ncomp; k++) {

             const int p = h->desc->comp[k].plane;

             const int start = k * (h->level_height + h->scale_height) * h->display_mode;

             double max_hval_log;
             unsigned max_hval = 0;

             for (i = 0; i < in->height; i++) {

                 src = in->data[p] + i * in->linesize[p];

                 for (j = 0; j < in->width; j++)

                     h->histogram[src[j]]++;
             }
 
             for (i = 0; i < 256; i++)

                 max_hval = FFMAX(max_hval, h->histogram[i]);
             max_hval_log = log2(max_hval + 1);

 
             for (i = 0; i < outlink->w; i++) {

                 int col_height;
 
                 if (h->levels_mode)

                     col_height = round(h->level_height * (1. - (log2(h->histogram[i] + 1) / max_hval_log)));

                 else

                     col_height = h->level_height - (h->histogram[i] * (int64_t)h->level_height + max_hval - 1) / max_hval;

                 for (j = h->level_height - 1; j >= col_height; j--) {
                     if (h->display_mode) {
                         for (l = 0; l < h->ncomp; l++)
                             out->data[l][(j + start) * out->linesize[l] + i] = h->fg_color[l];
                     } else {

                         out->data[p][(j + start) * out->linesize[p] + i] = 255;

                     }
                 }

                 for (j = h->level_height + h->scale_height - 1; j >= h->level_height; j--)

                     out->data[p][(j + start) * out->linesize[p] + i] = i;

             }
 
             memset(h->histogram, 0, 256 * sizeof(unsigned));
         }
         break;
     case MODE_WAVEFORM:

         for (k = 0; k < h->ncomp; k++) {

             const int offset = k * 256 * h->display_mode;

             gen_waveform(h, in, out, k, h->step, offset, h->waveform_mode);

         }
         break;
     case MODE_COLOR:
         for (i = 0; i < inlink->h; i++) {

             const int iw1 = i * in->linesize[1];
             const int iw2 = i * in->linesize[2];

             for (j = 0; j < inlink->w; j++) {

                 const int pos = in->data[1][iw1 + j] * out->linesize[0] + in->data[2][iw2 + j];

                 if (out->data[0][pos] < 255)
                     out->data[0][pos]++;
             }
         }
         for (i = 0; i < 256; i++) {
             dst = out->data[0] + i * out->linesize[0];
             for (j = 0; j < 256; j++) {
                 if (!dst[j]) {
                     out->data[1][i * out->linesize[0] + j] = i;
                     out->data[2][i * out->linesize[0] + j] = j;
                 }
             }
         }
         break;
     case MODE_COLOR2:
         for (i = 0; i < inlink->h; i++) {

             const int iw1 = i * in->linesize[1];
             const int iw2 = i * in->linesize[2];

             for (j = 0; j < inlink->w; j++) {

                 const int u = in->data[1][iw1 + j];
                 const int v = in->data[2][iw2 + j];
                 const int pos = u * out->linesize[0] + v;

                 if (!out->data[0][pos])
                     out->data[0][pos] = FFABS(128 - u) + FFABS(128 - v);
                 out->data[1][pos] = u;
                 out->data[2][pos] = v;
             }
         }
         break;
     default:
         av_assert0(0);
     }
 

     av_frame_free(&in);

     return ff_filter_frame(outlink, out);

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

 AVFilter ff_vf_histogram = {

     .name          = "histogram",
     .description   = NULL_IF_CONFIG_SMALL("Compute and draw a histogram."),
     .priv_size     = sizeof(HistogramContext),
     .query_formats = query_formats,
     .inputs        = inputs,
     .outputs       = outputs,
     .priv_class    = &histogram_class,
 };