/*
  * 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
     enum HistogramMode mode;
     unsigned       histogram[256];
     unsigned       max_hval;
     int            ncomp;
     const uint8_t  *bg_color;
     const uint8_t  *fg_color;
     int            level_height;
     int            scale_height;
     int            step;
     int            waveform_mode;

     int            display_mode;

 } 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" },

     { "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" },

     { NULL },
 };
 
 AVFILTER_DEFINE_CLASS(histogram);
 
 static av_cold int init(AVFilterContext *ctx, const char *args)
 {
     HistogramContext *h = ctx->priv;
     int ret;
 
     h->class = &histogram_class;
     av_opt_set_defaults(h);
 
     if ((ret = (av_set_options_string(h, args, "=", ":"))) < 0)
         return ret;
 
     return 0;
 }
 
 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_NONE
 };
 
 static int query_formats(AVFilterContext *ctx)
 {
     HistogramContext *h = ctx->priv;
     const enum AVPixelFormat *pix_fmts;
 
     switch (h->mode) {

     case MODE_WAVEFORM:

     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);
     }
 
     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
 
     return 0;
 }
 
 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;
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
 
     h->ncomp = desc->nb_components;
 
     switch (inlink->format) {
     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 int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *in)
 {
     HistogramContext *h   = inlink->dst->priv;
     AVFilterContext *ctx  = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     AVFilterBufferRef *out;
     const uint8_t *src;
     uint8_t *dst;
     int i, j, k, l, ret;
 
     out = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
     if (!out) {
         avfilter_unref_bufferp(&in);
         return AVERROR(ENOMEM);
     }
 
     out->pts = in->pts;
     out->pos = in->pos;
 
     for (k = 0; k < h->ncomp; k++)
         for (i = 0; i < outlink->h; i++)
             memset(out->data[k] + i * out->linesize[k], h->bg_color[k], outlink->w);
 
     switch (h->mode) {
     case MODE_LEVELS:
         for (k = 0; k < h->ncomp; k++) {

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

             for (i = 0; i < in->video->h; i++) {
                 src = in->data[k] + i * in->linesize[k];
                 for (j = 0; j < in->video->w; j++)
                     h->histogram[src[j]]++;
             }
 
             for (i = 0; i < 256; i++)
                 h->max_hval = FFMAX(h->max_hval, h->histogram[i]);
 
             for (i = 0; i < outlink->w; i++) {
                 int col_height = h->level_height - (float)h->histogram[i] / h->max_hval * h->level_height;
 

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

                 for (j = h->level_height + h->scale_height - 1; j >= h->level_height; j--)
                     out->data[k][(j + start) * out->linesize[k] + i] = i;
             }
 
             memset(h->histogram, 0, 256 * sizeof(unsigned));
             h->max_hval = 0;
         }
         break;
     case MODE_WAVEFORM:
         if (h->waveform_mode) {

             for (k = 0; k < h->ncomp; k++) {
                 int offset = k * 256 * h->display_mode;
                 for (i = 0; i < inlink->w; i++) {
                     for (j = 0; j < inlink->h; j++) {
                         int pos = (offset +
                                    in->data[k][j * in->linesize[k] + i]) *
                                   out->linesize[k] + i;
                         unsigned value = out->data[k][pos];
                         value = FFMIN(value + h->step, 255);
                         out->data[k][pos] = value;
                     }

                 }
             }
         } else {

             for (k = 0; k < h->ncomp; k++) {
                 int offset = k * 256 * h->display_mode;
                 for (i = 0; i < inlink->h; i++) {
                     src = in ->data[k] + i * in ->linesize[k];
                     dst = out->data[k] + i * out->linesize[k];
                     for (j = 0; j < inlink->w; j++) {
                         int pos = src[j] + offset;
                         unsigned value = dst[pos];
                         value = FFMIN(value + h->step, 255);
                         dst[pos] = value;
                     }

                 }
             }
         }
         break;
     case MODE_COLOR:
         for (i = 0; i < inlink->h; i++) {
             int iw1 = i * in->linesize[1];
             int iw2 = i * in->linesize[2];
             for (j = 0; j < inlink->w; j++) {
                 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++) {
             int iw1 = i * in->linesize[1];
             int iw2 = i * in->linesize[2];
             for (j = 0; j < inlink->w; j++) {
                 int u = in->data[1][iw1 + j];
                 int v = in->data[2][iw2 + j];
                 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);
     }
 
     ret = ff_filter_frame(outlink, out);
     avfilter_unref_bufferp(&in);
     if (ret < 0)
         return ret;
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     HistogramContext *h = ctx->priv;
 
     av_opt_free(h);
 }
 
 static const AVFilterPad inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
         .config_props = config_input,
         .min_perms    = AV_PERM_READ,
     },
     { NULL }
 };
 
 static const AVFilterPad outputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .config_props = config_output,
     },
     { NULL }
 };
 
 AVFilter avfilter_vf_histogram = {
     .name          = "histogram",
     .description   = NULL_IF_CONFIG_SMALL("Compute and draw a histogram."),
     .priv_size     = sizeof(HistogramContext),
     .init          = init,
     .uninit        = uninit,
     .query_formats = query_formats,
     .inputs        = inputs,
     .outputs       = outputs,
     .priv_class    = &histogram_class,
 };