/*
    This file is part of darktable,
    Copyright (C) 2010-2026 darktable developers.

    darktable is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    darktable 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with darktable.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <math.h>
#include <inttypes.h>
#include <stdlib.h>
#include <string.h>
#include <gtk/gtk.h>

#include "bauhaus/bauhaus.h"
#include "common/imagebuf.h"
#include "common/opencl.h"
#include "control/control.h"
#include "develop/develop.h"
#include "develop/imageop.h"
#include "develop/imageop_math.h"
#include "develop/imageop_gui.h"
#include "gui/accelerators.h"
#include "gui/gtk.h"
#include "iop/iop_api.h"


DT_MODULE_INTROSPECTION(2, dt_iop_velvia_params_t)

typedef struct dt_iop_velvia_params_t
{
  float strength; // $MIN: 0.0 $MAX: 100.0 $DEFAULT: 25.0
  float bias;     // $MIN: 0.0 $MAX: 1.0 $DEFAULT: 1.0 $DESCRIPTION: "mid-tones bias"
} dt_iop_velvia_params_t;

typedef struct dt_iop_velvia_gui_data_t
{
  GtkBox *vbox;
  GtkWidget *strength_scale;
  GtkWidget *bias_scale;
} dt_iop_velvia_gui_data_t;

typedef struct dt_iop_velvia_data_t
{
  float strength;
  float bias;
} dt_iop_velvia_data_t;

typedef struct dt_iop_velvia_global_data_t
{
  int kernel_velvia;
} dt_iop_velvia_global_data_t;


const char *name()
{
  return _("velvia");
}

const char *aliases()
{
  return _("saturation");
}

int flags()
{
  return IOP_FLAGS_INCLUDE_IN_STYLES | IOP_FLAGS_SUPPORTS_BLENDING | IOP_FLAGS_ALLOW_TILING;
}

int default_group()
{
  return IOP_GROUP_COLOR | IOP_GROUP_GRADING;
}

dt_iop_colorspace_type_t default_colorspace(dt_iop_module_t *self,
                                            dt_dev_pixelpipe_t *pipe,
                                            dt_dev_pixelpipe_iop_t *piece)
{
  return IOP_CS_RGB;
}

const char **description(dt_iop_module_t *self)
{
  return dt_iop_set_description(self, _("resaturate giving more weight to blacks,\n"
                                        "whites and low-saturation pixels"),
                                      _("creative"),
                                      _("linear, RGB, scene-referred"),
                                      _("linear, RGB"),
                                      _("linear, RGB, scene-referred"));
}

int legacy_params(dt_iop_module_t *self,
                  const void *const old_params,
                  const int old_version,
                  void **new_params,
                  int32_t *new_params_size,
                  int *new_version)
{
  typedef struct dt_iop_velvia_params_v2_t
  {
    float strength;
    float bias;
  } dt_iop_velvia_params_v2_t;

  if(old_version == 1)
  {
    typedef struct dt_iop_velvia_params_v1_t
    {
      float saturation;
      float vibrance;
      float luminance;
      float clarity;
    } dt_iop_velvia_params_v1_t;

    const dt_iop_velvia_params_v1_t *o = old_params;
    dt_iop_velvia_params_v2_t *n = malloc(sizeof(dt_iop_velvia_params_v2_t));
    n->strength = o->saturation * o->vibrance / 100.0f;
    n->bias = o->luminance;

    *new_params = n;
    *new_params_size = sizeof(dt_iop_velvia_params_v2_t);
    *new_version = 2;
    return 0;
  }
  return 1;
}

void process(dt_iop_module_t *self,
             dt_dev_pixelpipe_iop_t *piece,
             const void *const ivoid,
             void *const ovoid,
             const dt_iop_roi_t *const roi_in,
             const dt_iop_roi_t *const roi_out)
{
  if(!dt_iop_have_required_input_format(4 /*we need full-color pixels*/, self, piece->colors,
                                        ivoid, ovoid, roi_in, roi_out))
    return;
  const dt_iop_velvia_data_t *const data = piece->data;

  const float strength = data->strength / 100.0f;

  // Apply velvia saturation
  if(strength <= 0.0)
    dt_iop_image_copy_by_size(ovoid, ivoid, roi_out->width, roi_out->height, 4);
  else
  {
    const size_t npixels = (size_t)roi_out->width * roi_out->height;
    const float bias = data->bias;

    DT_OMP_FOR()
    for(size_t k = 0; k < npixels; k++)
    {
      const float *const in = (const float *const)ivoid + 4 * k;
      float *const out = (float *const)ovoid + 4 * k;

      // calculate vibrance, and apply boost velvia saturation at least saturated pixels
      float pmax = max3f(in);            // max value in RGB set
      float pmin = min3f(in);            // min value in RGB set
      float plum = (pmax + pmin) / 2.0f; // pixel luminocity
      float psat = (plum <= 0.5f) ? (pmax - pmin) / (1e-5f + pmax + pmin)
                                  : (pmax - pmin) / (1e-5f + MAX(0.0f, 2.0f - pmax - pmin));

      float pweight
          = CLAMPS(((1.0f - (1.5f * psat)) + ((1.0f + (fabsf(plum - 0.5f) * 2.0f)) * (1.0f - bias)))
                       / (1.0f + (1.0f - bias)),
                   0.0f, 1.0f);              // The weight of pixel
      float saturation = strength * pweight; // So lets calculate the final effect of filter on pixel

      // Apply velvia saturation values
      dt_aligned_pixel_t chan;
      copy_pixel(chan, in);
      // the compiler can use permute or shuffle instructions provided
      // we include all four values in the initializer; otherwise it
      // would need to build each element-by-element
      const dt_aligned_pixel_t rotate1 = { chan[1], chan[2], chan[0], chan[3] };
      const dt_aligned_pixel_t rotate2 = { chan[2], chan[0], chan[1], chan[3] };
      dt_aligned_pixel_t othersum;
      for_each_channel(c)
        othersum[c] = rotate1[c] + rotate2[c];
      dt_aligned_pixel_t velvia;
      for_each_channel(c)
        velvia[c] = CLAMPS(chan[c] + saturation * (chan[c] - 0.5f * othersum[c]), 0.0f, 1.0f);
      copy_pixel_nontemporal(out, velvia);
    }
    dt_omploop_sfence();  // ensure that nontemporal writes have flushed to RAM before continuing
  }
}

#ifdef HAVE_OPENCL
int process_cl(dt_iop_module_t *self, dt_dev_pixelpipe_iop_t *piece, cl_mem dev_in, cl_mem dev_out,
               const dt_iop_roi_t *const roi_in, const dt_iop_roi_t *const roi_out)
{
  dt_iop_velvia_data_t *data = piece->data;
  dt_iop_velvia_global_data_t *gd = self->global_data;

  cl_int err = DT_OPENCL_DEFAULT_ERROR;

  const int devid = piece->pipe->devid;
  const int width = roi_in->width;
  const int height = roi_in->height;

  const float strength = data->strength / 100.0f;
  const float bias = data->bias;


  if(strength <= 0.0f)
  {
    const size_t region[2] = { width, height };
    err = dt_opencl_enqueue_copy_image(devid, dev_in, dev_out, CLIMG_ORIGIN, CLIMG_ORIGIN, region);
  }
  else
  {
    err = dt_opencl_enqueue_kernel_2d_args(devid, gd->kernel_velvia, width, height,
      CLARG(dev_in), CLARG(dev_out), CLARG(width), CLARG(height), CLARG(strength), CLARG(bias));
  }
  return err;
}
#endif

void init_global(dt_iop_module_so_t *self)
{
  const int program = 8; // extended.cl, from programs.conf
  dt_iop_velvia_global_data_t *gd = malloc(sizeof(dt_iop_velvia_global_data_t));
  self->data = gd;
  gd->kernel_velvia = dt_opencl_create_kernel(program, "velvia");
}

void cleanup_global(dt_iop_module_so_t *self)
{
  dt_iop_velvia_global_data_t *gd = self->data;
  dt_opencl_free_kernel(gd->kernel_velvia);
  free(self->data);
  self->data = NULL;
}

void commit_params(dt_iop_module_t *self, dt_iop_params_t *p1, dt_dev_pixelpipe_t *pipe,
                   dt_dev_pixelpipe_iop_t *piece)
{
  dt_iop_velvia_params_t *p = (dt_iop_velvia_params_t *)p1;
  dt_iop_velvia_data_t *d = piece->data;

  d->strength = p->strength;
  d->bias = p->bias;
}

void init_pipe(dt_iop_module_t *self, dt_dev_pixelpipe_t *pipe, dt_dev_pixelpipe_iop_t *piece)
{
  piece->data = calloc(1, sizeof(dt_iop_velvia_data_t));
}

void cleanup_pipe(dt_iop_module_t *self, dt_dev_pixelpipe_t *pipe, dt_dev_pixelpipe_iop_t *piece)
{
  free(piece->data);
  piece->data = NULL;
}

void gui_update(dt_iop_module_t *self)
{
  dt_iop_velvia_gui_data_t *g = self->gui_data;
  dt_iop_velvia_params_t *p = self->params;
  dt_bauhaus_slider_set(g->strength_scale, p->strength);
  dt_bauhaus_slider_set(g->bias_scale, p->bias);
}

void gui_init(dt_iop_module_t *self)
{
  dt_iop_velvia_gui_data_t *g = IOP_GUI_ALLOC(velvia);

  g->strength_scale = dt_bauhaus_slider_from_params(self, N_("strength"));
  dt_bauhaus_slider_set_format(g->strength_scale, "%");
  gtk_widget_set_tooltip_text(g->strength_scale, _("the strength of saturation boost"));

  g->bias_scale = dt_bauhaus_slider_from_params(self, "bias");
  gtk_widget_set_tooltip_text(g->bias_scale, _("how much to spare highlights and shadows"));
}

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