/* babl - dynamically extendable universal pixel fish library.
 * Copyright (C) 2005, Øyvind Kolås.
 *
 * This library 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 3 of the License, or (at your option) any later version.
 *
 * This library 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 this library; if not, see
 * <https://www.gnu.org/licenses/>.
 */

#include "config.h"
#define NEEDS_BABL_DB
#include "babl-internal.h"
#include "babl-db.h"
#include <stddef.h>
#include <string.h>
#include <stdarg.h>

typedef struct _BablFindFish BablFindFish;

typedef struct _BablFindFish
{
  Babl       *fish_path;
  Babl       *fish_ref;
  Babl       *fish_fish;
  int        fishes;
  const Babl *source;
  const Babl *destination;
} _BablFishFish;


static int
match_conversion (Babl *conversion,
                  void *inout);

static int
find_fish_path (Babl *item,
                void *data);

static int
find_memcpy_fish (Babl *item,
                  void *data);

static int
find_fish_path (Babl *item,
                void *data)
{
  BablFindFish *ffish = (BablFindFish *) data;
  if ((item->fish.source == ffish->source) &&
      (item->fish.destination == ffish->destination))
    {
      if (item->instance.class_type == BABL_FISH_REFERENCE)
        {
          ffish->fish_ref = item;
          ffish->fishes++;
        }
      else if (item->instance.class_type == BABL_FISH_PATH)
        {
          ffish->fish_path = item;
          ffish->fishes++;
        }
      else if (item->instance.class_type == BABL_FISH)
        {
          ffish->fish_fish = item;
          ffish->fishes++;
        }
      if (ffish->fishes == 3)
        return 1;
    }

  return 0;
}

static int
find_memcpy_fish (Babl *item,
                  void *data)
{
  BablFindFish *ffish = (BablFindFish *) data;
  if ((item->fish.source == ffish->source) &&
      (item->fish.destination == ffish->destination))
    {
      if ((item->fish.source == item->fish.destination) &&
          (item->instance.class_type == BABL_FISH_REFERENCE))
        {
          ffish->fish_ref = item;
          return 1;
        }
    }

  return 0;
}

static int
match_conversion (Babl *conversion,
                  void *inout)
{
  void **data = inout;


  if ((Babl *) conversion->conversion.destination == (Babl *) *data)
    {
      *data = (void *) conversion;
      return 1;
    }

  return 0;
}



Babl *
babl_conversion_find (const void *source,
                      const void *destination)
{
  void *data = (void*)destination;

  if (BABL (source)->type.from_list)
    babl_list_each (BABL (source)->type.from_list, match_conversion, &data);
  if (data != (void*)destination) /* didn't change */
  {
    return data; /* found conversion */
  }
  data = NULL;

  if (BABL (source)->class_type == BABL_MODEL)
  {
     const Babl *srgb_source = BABL (source)->model.model ? BABL (source)->model.model:source;
     const Babl *srgb_destination = BABL (destination)->model.model ? BABL (destination)->model.model:destination;


     Babl *reference;

     if (srgb_source == source && srgb_destination == destination)
     {
        fprintf (stderr, "expected finding model conversion %s to %s", babl_get_name (source), babl_get_name (destination));
        return NULL;
     }

     reference = babl_conversion_find (srgb_source, srgb_destination);

  /* when conversions are sought between models, with non-sRGB chromaticities,
     we create the needed conversions from existing ones on the fly, and
     register them. The conversions registered by the models should pick up the
     RGB chromaticities, and TRC to use from the space on the model instead of
     hard-coding it.
   */

     switch (reference->instance.class_type)
     {
        case BABL_CONVERSION_LINEAR:
          return _conversion_new ("", 0, (void*)source, (void*)destination,
                            reference->conversion.function.linear,
                            NULL,
                            NULL,
                            reference->conversion.data, 1);
        case BABL_CONVERSION_PLANE:
          return _conversion_new ("", 0, source, destination,
                            NULL,
                            reference->conversion.function.plane,
                            NULL,
                            reference->conversion.data, 1);
        case BABL_CONVERSION_PLANAR:
          return _conversion_new ("", 0, source, destination,
                            NULL,
                            NULL,
                            reference->conversion.function.planar,
                            reference->conversion.data, 1);
     }
  }
  return NULL;
}

int
babl_fish_get_id (const Babl *source,
                  const Babl *destination)
{
  /* value of 'id' will be used as argument for hash function,
   * substraction serves as simple combination of
   * source/destination values. */
  int id = (((size_t)source * 93)) ^ ((size_t)destination);
  /* instances with id 0 won't be inserted into database */
  id *= ((((size_t)  (destination))) % 37);

  if (id == 0)
    id = 1;
  return id;
}

const Babl *
babl_fish (const void *source,
           const void *destination)
{
  const Babl *source_format      = NULL;
  const Babl *destination_format = NULL;

  babl_assert (source);
  babl_assert (destination);

  if (BABL_IS_BABL (source))
    source_format = source;

  if (!source_format)
    source_format = babl_format ((char *) source);

  if (!source_format)
    {
      babl_log ("args=(%p, %p) source format invalid", source, destination);
      return NULL;
    }

  if (BABL_IS_BABL (destination))
    destination_format = destination;

  if (!destination_format)
    destination_format = babl_format ((char *) destination);

  if (!destination_format)
    {
      babl_log ("args=(%p, %p) destination format invalid", source, destination);
      return NULL;
    }

  {
    int            hashval;
    BablHashTable *id_htable;
    BablFindFish   ffish = {(Babl *) NULL,
                            (Babl *) NULL,
                            (Babl *) NULL,
                            0,
                            (Babl *) NULL,
                            (Babl *) NULL};

    /* some vendor compilers can't compile non-constant elements of
     * compound struct initializers
     */
    ffish.source = source_format;
    ffish.destination = destination_format;

    id_htable = (babl_fish_db ())->id_hash;
    hashval = babl_hash_by_int (id_htable, babl_fish_get_id (source_format, destination_format));

    if (source_format == destination_format)
      {
        /* In the case of equal source and destination formats
         * we will search through the fish database for reference fish
         * to handle the memcpy */
        babl_hash_table_find (id_htable, hashval, find_memcpy_fish, (void *) &ffish);
      }
    else
      {
        /* In the case of different source and destination formats
         * we will search through the fish database for appropriate fish path
         * to handle the conversion. In the case that preexistent
         * fish path is found, we'll return it. In the case BABL_FISH
         * instance with the same source/destination is found, we'll
         * return reference fish.
         * In the case neither fish path nor BABL_FISH path are found,
         * we'll try to construct new fish path for requested
         * source/destination. In the case new fish path is found, we'll
         * return it, otherwise we'll create dummy BABL_FISH instance and
         * insert it into the fish database to indicate non-existent fish
         * path.
         */
        babl_hash_table_find (id_htable, hashval, find_fish_path, (void *) &ffish);
        if (ffish.fish_path)
          {
            /* we have found suitable fish path in the database */
            return ffish.fish_path;
          }

        babl_mutex_lock (babl_fish_mutex);
        /* do a second look in the database, in case another thread held the
           mutex and made the fish
         */
        if (!ffish.fish_fish)
        {
        babl_hash_table_find (id_htable, hashval, find_fish_path, (void *) &ffish);
        if (ffish.fish_path)
          {
            /* we have found suitable fish path in the database */
            babl_mutex_unlock (babl_fish_mutex);
            return ffish.fish_path;
          }
        }

        if (!ffish.fish_fish)
          {
            const Babl *src_space = (void*)source_format->format.space;
            const Babl *dst_space = (void*)destination_format->format.space;
            /* we haven't tried to search for suitable path yet */

            if (!babl_space_is_cmyk (src_space) &&
                !babl_space_is_cmyk (dst_space))
              {
                Babl *fish_path = babl_fish_path (source_format, destination_format);

                if (fish_path)
                  {
                    babl_mutex_unlock (babl_fish_mutex);
                    return fish_path;
                  }
#if 1
                else
                  {
                    /* there isn't a suitable path for requested formats,
                     * let's create a dummy BABL_FISH instance and insert
                     * it into the fish database to indicate that such path
                     * does not exist.
                     */
                    char *name = "X"; /* name does not matter */
                    Babl *fish = babl_calloc (1, sizeof (BablFish) + strlen (name) + 1);

                    fish->class_type                = BABL_FISH;
                    fish->instance.id               = babl_fish_get_id (source_format, destination_format);
                    fish->instance.name             = ((char *) fish) + sizeof (BablFish);
                    strcpy (fish->instance.name, name);
                    fish->fish.source               = source_format;
                    fish->fish.destination          = destination_format;
                    babl_db_insert (babl_fish_db (), fish);
                  }
#endif
                }
          }
        else if (ffish.fish_fish->fish.data)
          {
            /* the dummy fish was created by the cache, and we need to manually
             * show a "missing fast path" warning for it on the first lookup.
             */
#if 0
            _babl_fish_missing_fast_path_warning (ffish.fish_fish->fish.source,
                                                  ffish.fish_fish->fish.destination);
#endif

            ffish.fish_fish->fish.data = NULL;
          }
      }

    if (ffish.fish_ref)
      {
        /* we have already found suitable reference fish */
        babl_mutex_unlock (babl_fish_mutex);
        return ffish.fish_ref;
      }
    else
      {
        /* we have to create new reference fish */
        Babl *ret = babl_fish_reference (source_format, destination_format);
        babl_mutex_unlock (babl_fish_mutex);
        return ret;
      }
  }
}

BABL_CLASS_MINIMAL_IMPLEMENT (fish);
