/*
    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 <inttypes.h>
#include <memory>
#include <stdio.h>
#include <string.h>

#include <OpenEXR/ImfChannelList.h>
#include <OpenEXR/ImfFrameBuffer.h>
#include <OpenEXR/ImfInputFile.h>
#include <OpenEXR/ImfStandardAttributes.h>
#include <OpenEXR/ImfTestFile.h>
#include <OpenEXR/ImfThreading.h>
#include <OpenEXR/ImfTiledInputFile.h>

#include "common/colorspaces.h"
#include "common/darktable.h"
#include "common/exif.h"
#include "common/metadata.h"
#include "common/datetime.h"
#include "develop/develop.h"
#include "imageio/imageio_exr.h"
#include "imageio/imageio_exr.hh"

dt_imageio_retval_t dt_imageio_open_exr(dt_image_t *img,
                                        const char *filename,
                                        dt_mipmap_buffer_t *mbuf)
{
  bool isTiled = false;

  Imf::setGlobalThreadCount(dt_get_num_threads());

  std::unique_ptr<Imf::TiledInputFile> fileTiled;
  std::unique_ptr<Imf::InputFile> file;

  Imath::Box2i dw;
  Imf::FrameBuffer frameBuffer;
  int dx, dy;
  uint32_t xstride, ystride;


  /* verify openexr image */
  if(!Imf::isOpenExrFile((const char *)filename, isTiled))
    return DT_IMAGEIO_UNSUPPORTED_FORMAT;

  /* open exr file */
  try
  {
    if(isTiled)
    {
      std::unique_ptr<Imf::TiledInputFile> temp(new Imf::TiledInputFile(filename));
      fileTiled = std::move(temp);
    }
    else
    {
      std::unique_ptr<Imf::InputFile> temp(new Imf::InputFile(filename));
      file = std::move(temp);
    }
  }
  catch(const std::exception &e)
  {
    return DT_IMAGEIO_LOAD_FAILED;
  }

  const Imf::Header &header = isTiled ? fileTiled->header() : file->header();

  /* check that channels available is any of supported RGB(a) */
  bool hasR = false;
  bool hasG = false;
  bool hasB = false;

  for(Imf::ChannelList::ConstIterator i = header.channels().begin();
      i != header.channels().end();
      ++i)
  {
    std::string name(i.name());
    if(name == "R") hasR = true;
    if(name == "G") hasG = true;
    if(name == "B") hasB = true;
  }
  if(!(hasR && hasG && hasB))
  {
    dt_print(DT_DEBUG_ALWAYS,
             "[exr_open] error: only images with RGB(A) channels are supported,"
             " skipping '%s'", img->filename);
    return DT_IMAGEIO_UNSUPPORTED_FEATURE;
  }

  if(!img->exif_inited)
  {
    // read back exif data, either as embedded blob or "standard" attributes
    // if another software is able to update these exif data, the former test
    // should be removed to take the potential changes in account (not done
    // by normal import image flow)
    const Imf::BlobAttribute *exif = header.findTypedAttribute<Imf::BlobAttribute>("exif");
    if(exif)
    {
      uint8_t *exif_blob = exif->value().data.get();
      uint32_t exif_size = exif->value().size;
      /* skip any superfluous "Exif\0\0" APP1 prefix written by dt 4.0.0 and earlier */
      if(exif_size >= 6 && !memcmp(exif_blob, "Exif\0\0", 6))
      {
        exif_blob += 6;
        exif_size -= 6;
      }
      if(exif_size > 0) dt_exif_read_from_blob(img, exif_blob, exif_size);
    }
    else
    {
      if(Imf::hasOwner(header))
      {
        dt_metadata_set_import_lock(img->id, "Xmp.dc.rights",
                                    Imf::owner(header).c_str());
      }
      if(Imf::hasComments(header))
      {
        dt_metadata_set_import_lock(img->id, "Xmp.dc.description",
                                    Imf::comments(header).c_str());
      }
      if(Imf::hasCapDate(header))
      {
        // utcOffset can be ignored for now, see dt_datetime_exif_to_numbers()
        char *datetime = strdup(Imf::capDate(header).c_str());
        dt_datetime_exif_to_img(img, datetime);
        free(datetime);
      }
      if(Imf::hasLongitude(header) && Imf::hasLatitude(header))
      {
        img->geoloc.longitude = Imf::longitude(header);
        img->geoloc.latitude = Imf::latitude(header);
      }
      if(Imf::hasAltitude(header))
        img->geoloc.elevation = Imf::altitude(header);
      if(Imf::hasFocus(header))
        img->exif_focus_distance = Imf::focus(header);
      if(Imf::hasExpTime(header))
        img->exif_exposure = Imf::expTime(header);
      if(Imf::hasAperture(header))
        img->exif_aperture = Imf::aperture(header);
      if(Imf::hasIsoSpeed(header))
        img->exif_iso = Imf::isoSpeed(header);

// the OPENEXR_VERSION_HEX macro is broken for 3.2.0 and earlier, must compute directly
#if(((OPENEXR_VERSION_MAJOR << 24) | (OPENEXR_VERSION_MINOR << 16) | (OPENEXR_VERSION_PATCH << 8)) >= 0x03020000)
      if(Imf::hasCameraMake(header))
      {
        g_strlcpy(img->exif_maker,
                  Imf::cameraMake(header).c_str(), sizeof(img->exif_maker));
      }
      if(Imf::hasCameraModel(header))
      {
        g_strlcpy(img->exif_model,
                  Imf::cameraModel(header).c_str(), sizeof(img->exif_model));
      }
      // Make sure we copy the exif make and model to the correct place if needed
      dt_image_refresh_makermodel(img);

      if(Imf::hasLensModel(header))
      {
        g_strlcpy(img->exif_lens,
                  Imf::lensModel(header).c_str(), sizeof(img->exif_lens));

        if(Imf::hasLensMake(header) && Imf::lensMake(header) == "Canon")
        {
          /* Use pretty name for Canon RF & RF-S lenses (as exiftool/exiv2/lensfun) */
          if(g_str_has_prefix(img->exif_lens, "RF"))
          {
            std::string pretty;
            if(img->exif_lens[2] == '-')
              pretty = "Canon RF-S " + std::string(&img->exif_lens[4]);
            else
              pretty = "Canon RF " + std::string(&img->exif_lens[2]);
            g_strlcpy(img->exif_lens, pretty.c_str(), sizeof(img->exif_lens));
          }
        }

        // Capitalize lenses properly for UI presentation, e.g.
        // Nikon Z-mount: Nikkor, Tamron
        // Leica L-mount: Viltrox
        if(g_str_has_prefix(img->exif_lens, "NIKKOR ")
           || g_str_has_prefix(img->exif_lens, "TAMRON ")
           || g_str_has_prefix(img->exif_lens, "VILTROX"))
        {
          for(size_t i = 1; i <= 6; ++i)
            img->exif_lens[i] = g_ascii_tolower(img->exif_lens[i]);
        }

        // Handle Sigma lenses on modern bodies (e.g. Nikon Z) using already clean
        // lensMake and lensModel.
        if(Imf::hasLensMake(header) && Imf::lensMake(header) == "SIGMA"
           && g_ascii_strcasecmp(img->exif_lens, "Sigma"))
        {
          std::string pretty = "Sigma " + std::string(img->exif_lens);
          g_strlcpy(img->exif_lens, pretty.c_str(), sizeof(img->exif_lens));
        }
      }

      if(Imf::hasNominalFocalLength(header))
        img->exif_focal_length = Imf::nominalFocalLength(header);
#endif
    }
  }

  /* get image width and height from data window only */
  dw = header.dataWindow();
  img->width = dw.max.x - dw.min.x + 1;
  img->height = dw.max.y - dw.min.y + 1;

  // Try to allocate image data
  img->buf_dsc.channels = 4;
  img->buf_dsc.datatype = TYPE_FLOAT;
  float *buf = (float *)dt_mipmap_cache_alloc(mbuf, img);
  if(!buf)
  {
    dt_print(DT_DEBUG_ALWAYS,
             "[exr_open] error: could not alloc full buffer for image '%s'",
             img->filename);
    return DT_IMAGEIO_CACHE_FULL;
  }

  /* set up frame buffer relative to data window */
  dx = dw.min.x;
  dy = dw.min.y;
  xstride = sizeof(float) * 4;
  ystride = sizeof(float) * img->width * 4;
  frameBuffer.insert(
      "R", Imf::Slice(Imf::FLOAT, (char *)(buf - dx * 4 - dy * img->width * 4 + 0),
                      xstride, ystride, 1, 1, 0.0));
  frameBuffer.insert(
      "G", Imf::Slice(Imf::FLOAT, (char *)(buf - dx * 4 - dy * img->width * 4 + 1),
                      xstride, ystride, 1, 1, 0.0));
  frameBuffer.insert(
      "B", Imf::Slice(Imf::FLOAT, (char *)(buf - dx * 4 - dy * img->width * 4 + 2),
                      xstride, ystride, 1, 1, 0.0));
  frameBuffer.insert(
      "A", Imf::Slice(Imf::FLOAT, (char *)(buf - dx * 4 - dy * img->width * 4 + 3),
                      xstride, ystride, 1, 1, 0.0));

  try
  {
    if(isTiled)
    {
      fileTiled->setFrameBuffer(frameBuffer);
      fileTiled->readTiles(0, fileTiled->numXTiles() - 1, 0, fileTiled->numYTiles() - 1);
    }
    else
    {
      file->setFrameBuffer(frameBuffer);
      file->readPixels(dw.min.y, dw.max.y);
    }
  }
  catch(const std::exception &e)
  {
    dt_print(DT_DEBUG_ALWAYS,
             "[exr_open] error: could not read from '%s' due to: %s",
             img->filename, e.what());
    return DT_IMAGEIO_FILE_CORRUPTED;
  }

  /* try to get the chromaticities and whitepoint. this will add the
   * default linear rec709 profile when nothing was embedded and look
   * as if it was embedded in colorin. better than defaulting to
   * something wrong there. */
  Imf::Chromaticities chromaticities;
  float whiteLuminance = 1.0f;

  if(Imf::hasChromaticities(header))
  {
    chromaticities = Imf::chromaticities(header);

    /* adapt chromaticities to D65 expected by colorin */
    cmsCIExyY red_xy = { chromaticities.red[0],
                         chromaticities.red[1], 1.0 };
    cmsCIEXYZ srcRed;
    cmsxyY2XYZ(&srcRed, &red_xy);

    cmsCIExyY green_xy = { chromaticities.green[0],
                           chromaticities.green[1], 1.0 };
    cmsCIEXYZ srcGreen;
    cmsxyY2XYZ(&srcGreen, &green_xy);

    cmsCIExyY blue_xy = { chromaticities.blue[0],
                          chromaticities.blue[1], 1.0 };
    cmsCIEXYZ srcBlue;
    cmsxyY2XYZ(&srcBlue, &blue_xy);

    const cmsCIExyY srcWhite_xy = { chromaticities.white[0],
                                    chromaticities.white[1], 1.0 };
    cmsCIEXYZ srcWhite;
    cmsxyY2XYZ(&srcWhite, &srcWhite_xy);

    /* use Imf::Chromaticities definition */
    const cmsCIExyY d65_xy = {0.3127f, 0.3290f, 1.0};
    cmsCIEXYZ d65;
    cmsxyY2XYZ(&d65, &d65_xy);

    cmsCIEXYZ dstRed;
    cmsAdaptToIlluminant(&dstRed, &srcWhite, &d65, &srcRed);

    cmsCIEXYZ dstGreen;
    cmsAdaptToIlluminant(&dstGreen, &srcWhite, &d65, &srcGreen);

    cmsCIEXYZ dstBlue;
    cmsAdaptToIlluminant(&dstBlue, &srcWhite, &d65, &srcBlue);

    cmsXYZ2xyY(&red_xy, &dstRed);
    chromaticities.red[0] = (float)red_xy.x;
    chromaticities.red[1] = (float)red_xy.y;

    cmsXYZ2xyY(&green_xy, &dstGreen);
    chromaticities.green[0] = (float)green_xy.x;
    chromaticities.green[1] = (float)green_xy.y;

    cmsXYZ2xyY(&blue_xy, &dstBlue);
    chromaticities.blue[0] = (float)blue_xy.x;
    chromaticities.blue[1] = (float)blue_xy.y;

    chromaticities.white[0] = 0.3127f;
    chromaticities.white[1] = 0.3290f;
  }

  if(Imf::hasWhiteLuminance(header))
    whiteLuminance = Imf::whiteLuminance(header);

  Imath::M44f m = Imf::XYZtoRGB(chromaticities, whiteLuminance);

  for(int i = 0; i < 3; i++)
    for(int j = 0; j < 3; j++)
    {
      img->d65_color_matrix[3 * i + j] = m[j][i];
    }

  img->buf_dsc.cst = IOP_CS_RGB;
  img->buf_dsc.filters = 0u;
  img->flags &= ~DT_IMAGE_RAW;
  img->flags &= ~DT_IMAGE_S_RAW;
  img->flags &= ~DT_IMAGE_LDR;
  img->flags |= DT_IMAGE_HDR;

  img->loader = LOADER_EXR;
  return DT_IMAGEIO_OK;
}

// clang-format off
// modelines: These editor modelines have been set for all relevant files by tools/update_modelines.py
// vim: shiftwidth=2 expandtab tabstop=2 cindent
// kate: tab-indents: off; indent-width 2; replace-tabs on; indent-mode cstyle; remove-trailing-spaces modified;
// clang-format on