/*
 * 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 2020, Blender Foundation.
 * All rights reserved.
 */

/** \file
 * \ingroup gpu
 */

#pragma once

#include "gpu_context_private.hh"

#include "GPU_framebuffer.h"

#include "BLI_set.hh"
#include "BLI_vector.hh"

#include "gl_state.hh"

#include "glew-mx.h"

#include <mutex>

namespace blender {
namespace gpu {

class GLVaoCache;

class GLSharedOrphanLists {
 public:
  /** Mutex for the below structures. */
  std::mutex lists_mutex;
  /** Buffers and textures are shared across context. Any context can free them. */
  Vector<GLuint> textures;
  Vector<GLuint> buffers;

 public:
  void orphans_clear(void);
};

class GLContext : public Context {
 public:
  /** Capabilities. */
  static GLint max_cubemap_size;
  static GLint max_texture_3d_size;
  static GLint max_ubo_size;
  static GLint max_ubo_binds;
  /** Extensions. */
  static bool base_instance_support;
  static bool clear_texture_support;
  static bool copy_image_support;
  static bool debug_layer_support;
  static bool direct_state_access_support;
  static bool fixed_restart_index_support;
  static bool multi_bind_support;
  static bool multi_draw_indirect_support;
  static bool shader_draw_parameters_support;
  static bool texture_cube_map_array_support;
  static bool texture_filter_anisotropic_support;
  static bool texture_gather_support;
  static bool vertex_attrib_binding_support;
  /** Workarounds. */
  static bool debug_layer_workaround;
  static bool unused_fb_slot_workaround;
  static float derivative_signs[2];

  /** VBO for missing vertex attrib binding. Avoid undefined behavior on some implementation. */
  GLuint default_attr_vbo_;

  /** Used for debugging purpose. Bitflags of all bound slots. */
  uint16_t bound_ubo_slots;

 private:
  /**
   * #GPUBatch & #GPUFramebuffer have references to the context they are from, in the case the
   * context is destroyed, we need to remove any reference to it.
   */
  Set<GLVaoCache *> vao_caches_;
  Set<GPUFrameBuffer *> framebuffers_;
  /** Mutex for the below structures. */
  std::mutex lists_mutex_;
  /** VertexArrays and framebuffers are not shared across context. */
  Vector<GLuint> orphaned_vertarrays_;
  Vector<GLuint> orphaned_framebuffers_;
  /** #GLBackend owns this data. */
  GLSharedOrphanLists &shared_orphan_list_;

 public:
  GLContext(void *ghost_window, GLSharedOrphanLists &shared_orphan_list);
  ~GLContext();

  static void check_error(const char *info);

  void activate(void) override;
  void deactivate(void) override;

  void flush(void) override;
  void finish(void) override;

  void memory_statistics_get(int *total_mem, int *free_mem) override;

  static GLContext *get()
  {
    return static_cast<GLContext *>(Context::get());
  }

  static GLStateManager *state_manager_active_get()
  {
    GLContext *ctx = GLContext::get();
    return static_cast<GLStateManager *>(ctx->state_manager);
  };

  /* These need to be called with the context the id was created with. */
  void vao_free(GLuint vao_id);
  void fbo_free(GLuint fbo_id);
  /* These can be called by any threads even without OpenGL ctx. Deletion will be delayed. */
  static void buf_free(GLuint buf_id);
  static void tex_free(GLuint tex_id);

  void vao_cache_register(GLVaoCache *cache);
  void vao_cache_unregister(GLVaoCache *cache);

  void debug_group_begin(const char *name, int index) override;
  void debug_group_end(void) override;

 private:
  static void orphans_add(Vector<GLuint> &orphan_list, std::mutex &list_mutex, GLuint id);
  void orphans_clear(void);

  MEM_CXX_CLASS_ALLOC_FUNCS("GLContext")
};

}  // namespace gpu
}  // namespace blender