/*
 * This program 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 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * Copyright 2021, Blender Foundation.
 */

/** \file
 * \ingroup draw
 */

#include "BLI_vector.hh"

#include "GPU_viewport.h"

#include "DRW_render.h"

#include "draw_instance_data.h"

#include "draw_manager_text.h"

#include "draw_manager.h"
#include "draw_view_data.h"

using namespace blender;

struct DRWViewData {
  DefaultFramebufferList dfbl = {};
  DefaultTextureList dtxl = {};
  /** True indicates the textures inside dtxl are from the viewport and should not be freed. */
  bool from_viewport = false;
  /** Common size for texture in the engines texture list.
   * We free all texture lists if it changes. */
  int texture_list_size[2] = {0, 0};

  double cache_time = 0.0;

  Vector<ViewportEngineData> engines;
  Vector<ViewportEngineData *> enabled_engines;
};

DRWViewData *DRW_view_data_create(ListBase *engine_types)
{
  DRWViewData *view_data = new DRWViewData();
  LISTBASE_FOREACH (DRWRegisteredDrawEngine *, type, engine_types) {
    ViewportEngineData engine = {};
    engine.engine_type = type;
    view_data->engines.append(engine);
  }
  return view_data;
}

void DRW_view_data_default_lists_from_viewport(DRWViewData *view_data, GPUViewport *viewport)
{
  int active_view = GPU_viewport_active_view_get(viewport);
  view_data->from_viewport = true;

  DefaultFramebufferList *dfbl = &view_data->dfbl;
  DefaultTextureList *dtxl = &view_data->dtxl;
  /* Depth texture is shared between both stereo views. */
  dtxl->depth = GPU_viewport_depth_texture(viewport);
  dtxl->color = GPU_viewport_color_texture(viewport, active_view);
  dtxl->color_overlay = GPU_viewport_overlay_texture(viewport, active_view);

  GPU_framebuffer_ensure_config(&dfbl->default_fb,
                                {
                                    GPU_ATTACHMENT_TEXTURE(dtxl->depth),
                                    GPU_ATTACHMENT_TEXTURE(dtxl->color),
                                });
  GPU_framebuffer_ensure_config(&dfbl->overlay_fb,
                                {
                                    GPU_ATTACHMENT_TEXTURE(dtxl->depth),
                                    GPU_ATTACHMENT_TEXTURE(dtxl->color_overlay),
                                });
  GPU_framebuffer_ensure_config(&dfbl->depth_only_fb,
                                {
                                    GPU_ATTACHMENT_TEXTURE(dtxl->depth),
                                    GPU_ATTACHMENT_NONE,
                                });
  GPU_framebuffer_ensure_config(&dfbl->color_only_fb,
                                {
                                    GPU_ATTACHMENT_NONE,
                                    GPU_ATTACHMENT_TEXTURE(dtxl->color),
                                });
  GPU_framebuffer_ensure_config(&dfbl->overlay_only_fb,
                                {
                                    GPU_ATTACHMENT_NONE,
                                    GPU_ATTACHMENT_TEXTURE(dtxl->color_overlay),
                                });
}

static void draw_viewport_engines_data_clear(ViewportEngineData *data)
{
  DrawEngineType *engine_type = data->engine_type->draw_engine;
  const DrawEngineDataSize *data_size = engine_type->vedata_size;

  for (int i = 0; data->fbl && i < data_size->fbl_len; i++) {
    GPU_FRAMEBUFFER_FREE_SAFE(data->fbl->framebuffers[i]);
  }
  for (int i = 0; data->txl && i < data_size->txl_len; i++) {
    GPU_TEXTURE_FREE_SAFE(data->txl->textures[i]);
  }
  for (int i = 0; data->stl && i < data_size->stl_len; i++) {
    MEM_SAFE_FREE(data->stl->storage[i]);
  }

  if (data->instance_data) {
    BLI_assert(engine_type->instance_free != nullptr);
    engine_type->instance_free(data->instance_data);
    data->instance_data = nullptr;
  }

  MEM_SAFE_FREE(data->fbl);
  MEM_SAFE_FREE(data->txl);
  MEM_SAFE_FREE(data->psl);
  MEM_SAFE_FREE(data->stl);

  if (data->text_draw_cache) {
    DRW_text_cache_destroy(data->text_draw_cache);
    data->text_draw_cache = nullptr;
  }
}

static void draw_view_data_clear(DRWViewData *view_data)
{
  GPU_FRAMEBUFFER_FREE_SAFE(view_data->dfbl.default_fb);
  GPU_FRAMEBUFFER_FREE_SAFE(view_data->dfbl.overlay_fb);
  GPU_FRAMEBUFFER_FREE_SAFE(view_data->dfbl.in_front_fb);
  GPU_FRAMEBUFFER_FREE_SAFE(view_data->dfbl.color_only_fb);
  GPU_FRAMEBUFFER_FREE_SAFE(view_data->dfbl.depth_only_fb);
  GPU_FRAMEBUFFER_FREE_SAFE(view_data->dfbl.overlay_only_fb);

  if (!view_data->from_viewport) {
    GPU_TEXTURE_FREE_SAFE(view_data->dtxl.color);
    GPU_TEXTURE_FREE_SAFE(view_data->dtxl.color_overlay);
    GPU_TEXTURE_FREE_SAFE(view_data->dtxl.depth);
  }
  GPU_TEXTURE_FREE_SAFE(view_data->dtxl.depth_in_front);

  for (ViewportEngineData &engine : view_data->engines) {
    draw_viewport_engines_data_clear(&engine);
  }

  view_data->texture_list_size[0] = view_data->texture_list_size[1] = 0;
  view_data->cache_time = 0.0f;
}

void DRW_view_data_free(DRWViewData *view_data)
{
  draw_view_data_clear(view_data);
  delete view_data;
}

void DRW_view_data_texture_list_size_validate(DRWViewData *view_data, const int size[2])
{
  if (!equals_v2v2_int(view_data->texture_list_size, size)) {
    draw_view_data_clear(view_data);
    copy_v2_v2_int(view_data->texture_list_size, size);
  }
}

ViewportEngineData *DRW_view_data_engine_data_get_ensure(DRWViewData *view_data,
                                                         DrawEngineType *engine_type)
{
  for (ViewportEngineData &engine : view_data->engines) {
    if (engine.engine_type->draw_engine == engine_type) {
      if (engine.fbl == nullptr) {
        const DrawEngineDataSize *data_size = engine_type->vedata_size;
        engine.fbl = (FramebufferList *)MEM_calloc_arrayN(
            data_size->fbl_len, sizeof(GPUFrameBuffer *), "FramebufferList");
        engine.txl = (TextureList *)MEM_calloc_arrayN(
            data_size->txl_len, sizeof(GPUTexture *), "TextureList");
        engine.psl = (PassList *)MEM_calloc_arrayN(
            data_size->psl_len, sizeof(DRWPass *), "PassList");
        engine.stl = (StorageList *)MEM_calloc_arrayN(
            data_size->stl_len, sizeof(void *), "StorageList");
      }
      return &engine;
    }
  }
  return nullptr;
}

void DRW_view_data_use_engine(DRWViewData *view_data, DrawEngineType *engine_type)
{
  ViewportEngineData *engine = DRW_view_data_engine_data_get_ensure(view_data, engine_type);
  view_data->enabled_engines.append(engine);
}

void DRW_view_data_reset(DRWViewData *view_data)
{
  view_data->enabled_engines.clear();
}

void DRW_view_data_free_unused(DRWViewData *view_data)
{
  for (ViewportEngineData &engine : view_data->engines) {
    if (view_data->enabled_engines.first_index_of_try(&engine) == -1) {
      draw_viewport_engines_data_clear(&engine);
    }
  }
}

double *DRW_view_data_cache_time_get(DRWViewData *view_data)
{
  return &view_data->cache_time;
}

DefaultFramebufferList *DRW_view_data_default_framebuffer_list_get(DRWViewData *view_data)
{
  return &view_data->dfbl;
}

DefaultTextureList *DRW_view_data_default_texture_list_get(DRWViewData *view_data)
{
  return &view_data->dtxl;
}

void DRW_view_data_enabled_engine_iter_begin(DRWEngineIterator *iterator, DRWViewData *view_data)
{
  iterator->id = 0;
  iterator->end = view_data->enabled_engines.size();
  iterator->engines = view_data->enabled_engines.data();
}

ViewportEngineData *DRW_view_data_enabled_engine_iter_step(DRWEngineIterator *iterator)
{
  if (iterator->id >= iterator->end) {
    return nullptr;
  }
  ViewportEngineData *engine = iterator->engines[iterator->id++];
  return engine;
}