/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2011-2016 - Daniel De Matteis
 * 
 *  RetroArch 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 Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  RetroArch 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 RetroArch.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

#include <string.h>

#include <string/stdstring.h>

#include "video_shader_driver.h"
#include "../verbosity.h"

static const shader_backend_t *shader_ctx_drivers[] = {
#ifdef HAVE_GLSL
   &gl_glsl_backend,
#endif
#ifdef HAVE_CG
   &gl_cg_backend,
#endif
#ifdef HAVE_HLSL
   &hlsl_backend,
#endif
   &shader_null_backend,
   NULL
};

static const shader_backend_t *current_shader;
static void *shader_data;

/**
 * shader_ctx_find_driver:
 * @ident                   : Identifier of shader context driver to find.
 *
 * Finds shader context driver and initializes.
 *
 * Returns: shader context driver if found, otherwise NULL.
 **/
const shader_backend_t *shader_ctx_find_driver(const char *ident)
{
   unsigned i;

   for (i = 0; shader_ctx_drivers[i]; i++)
   {
      if (string_is_equal(shader_ctx_drivers[i]->ident, ident))
         return shader_ctx_drivers[i];
   }

   return NULL;
}

struct video_shader *video_shader_driver_get_current_shader(void)
{
   void *video_driver                       = video_driver_get_ptr(false);
   const video_poke_interface_t *video_poke = video_driver_get_poke();
   if (!video_poke || !video_driver)
      return NULL;
   if (!video_poke->get_current_shader)
      return NULL;
   return video_poke->get_current_shader(video_driver);
}

void video_shader_driver_scale(unsigned idx, struct gfx_fbo_scale *scale)
{
   if (!scale || !current_shader)
      return;

   scale->valid = false;

   if (current_shader->shader_scale)
      current_shader->shader_scale(shader_data, idx, scale);
}

void video_shader_driver_use(void *data, unsigned index)
{
   if (!current_shader)
      return;
   current_shader->use(data, shader_data, index);
}

const char *video_shader_driver_get_ident(void)
{
   if (!current_shader)
      return NULL;
   return current_shader->ident;
}

bool video_shader_driver_mipmap_input(unsigned index)
{
   if (!current_shader)
      return false;
   return current_shader->mipmap_input(shader_data, index);
}

unsigned video_shader_driver_num_shaders(void)
{
   if (!current_shader)
      return 0;
   return current_shader->num_shaders(shader_data);
}

unsigned video_shader_driver_get_prev_textures(void)
{
   if (!current_shader)
      return 0;
   return current_shader->get_prev_textures(shader_data);
}

bool video_shader_driver_set_coords(void *handle_data, const void *data)
{
   if (!current_shader || !current_shader->set_coords)
      return false;
   return current_shader->set_coords(handle_data, shader_data, data);
}

bool video_shader_driver_set_mvp(void *data, const math_matrix_4x4 *mat)
{
   if (!current_shader || !current_shader->set_mvp || !mat)
      return false;
   return current_shader->set_mvp(data, shader_data, mat);
}

bool video_shader_driver_filter_type(unsigned index, bool *smooth)
{
   if (!current_shader || !current_shader->filter_type)
      return false;
   return current_shader->filter_type(shader_data, index, smooth);
}

enum gfx_wrap_type video_shader_driver_wrap_type(unsigned index)
{
   return current_shader->wrap_type(shader_data, index);
}

struct video_shader *video_shader_driver_direct_get_current_shader(void)
{
   if (!current_shader || !current_shader->get_current_shader)
      return NULL;
   return current_shader->get_current_shader(shader_data);
}

bool video_shader_driver_ctl(enum video_shader_driver_ctl_state state, void *data)
{
   switch (state)
   {
      case SHADER_CTL_DEINIT:
         if (!current_shader)
            return false;

         if (current_shader->deinit)
            current_shader->deinit(shader_data);

         shader_data    = NULL;
         current_shader = NULL;
         break;
      case SHADER_CTL_SET_PARAMS:
         {
            video_shader_ctx_params_t *params = (video_shader_ctx_params_t*)data;

            if (!current_shader || !current_shader->set_params)
               return false;
            current_shader->set_params(
                  params->data,
                  shader_data,
                  params->width,
                  params->height,
                  params->tex_width,
                  params->tex_height,
                  params->out_width,
                  params->out_height,
                  params->frame_counter,
                  params->info,
                  params->prev_info,
                  params->feedback_info,
                  params->fbo_info,
                  params->fbo_info_cnt);
         }
         break;
         /* Finds first suitable shader context driver. */
      case SHADER_CTL_INIT_FIRST:
         {
            unsigned i;

            for (i = 0; shader_ctx_drivers[i]; i++)
            {
               current_shader = shader_ctx_drivers[i];
               return true;
            }
         }
         return false;
      case SHADER_CTL_INIT:
         {
            video_shader_ctx_init_t *init = (video_shader_ctx_init_t*)data;
            void *tmp = NULL;

            if (!init->shader || !init->shader->init)
               return false;

            tmp = init->shader->init(init->data, init->path);

            if (!tmp)
               return false;

            shader_data    = tmp;
            current_shader = init->shader;
         }
         break;
      case SHADER_CTL_GET_FEEDBACK_PASS:
         if (!current_shader || !current_shader->get_feedback_pass)
            return false;
         return current_shader->get_feedback_pass(shader_data, (unsigned*)data);
      case SHADER_CTL_NONE:
      default:
         break;
   }

   return true;
}