/*
 * 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.
 *
 * The Original Code is Copyright (C) 2020 Blender Foundation.
 * All rights reserved.
 */

/** \file
 * \ingroup gpu
 *
 * GPU Framebuffer
 * - this is a wrapper for an OpenGL framebuffer object (FBO). in practice
 *   multiple FBO's may be created.
 * - actual FBO creation & config is deferred until GPU_framebuffer_bind or
 *   GPU_framebuffer_check_valid to allow creation & config while another
 *   opengl context is bound (since FBOs are not shared between ogl contexts).
 */

#pragma once

#include "MEM_guardedalloc.h"

#include "BLI_assert.h"

#include "gpu_texture_private.hh"

#include "glew-mx.h"

struct GPUFrameBuffer;

namespace blender {
namespace gpu {

class GLTexture : public Texture {
  friend class GLStateManager;

 private:
  /** All samplers states. */
  static GLuint samplers_[GPU_SAMPLER_MAX];

  /** Target to bind the texture to (GL_TEXTURE_1D, GL_TEXTURE_2D, etc...)*/
  GLenum target_ = -1;
  /** opengl identifier for texture. */
  GLuint tex_id_ = 0;
  /** Legacy workaround for texture copy. Created when using framebuffer_get(). */
  struct GPUFrameBuffer *framebuffer_ = NULL;
  /** True if this texture is bound to at least one texture unit. */
  /* TODO(fclem) How do we ensure thread safety here? */
  bool is_bound_ = false;

 public:
  GLTexture(const char *name);
  ~GLTexture();

  void update_sub(
      int mip, int offset[3], int extent[3], eGPUDataFormat type, const void *data) override;

  void generate_mipmap(void) override;
  void copy_to(Texture *dst) override;
  void clear(eGPUDataFormat format, const void *data) override;
  void swizzle_set(const char swizzle_mask[4]) override;
  void mip_range_set(int min, int max) override;
  void *read(int mip, eGPUDataFormat type) override;

  void check_feedback_loop(void);

  /* TODO(fclem) Legacy. Should be removed at some point. */
  uint gl_bindcode_get(void) const override;

  static void samplers_init(void);
  static void samplers_free(void);
  static void samplers_update(void);

 protected:
  bool init_internal(void) override;
  bool init_internal(GPUVertBuf *vbo) override;

 private:
  bool proxy_check(int mip);
  void ensure_mipmaps(int mip);
  void update_sub_direct_state_access(
      int mip, int offset[3], int extent[3], GLenum gl_format, GLenum gl_type, const void *data);
  GPUFrameBuffer *framebuffer_get(void);

  MEM_CXX_CLASS_ALLOC_FUNCS("GLTexture")
};

inline GLenum to_gl_internal_format(eGPUTextureFormat format)
{
  /* You can add any of the available type to this list
   * For available types see GPU_texture.h */
  switch (format) {
    /* Formats texture & renderbuffer */
    case GPU_RGBA8UI:
      return GL_RGBA8UI;
    case GPU_RGBA8I:
      return GL_RGBA8I;
    case GPU_RGBA8:
      return GL_RGBA8;
    case GPU_RGBA32UI:
      return GL_RGBA32UI;
    case GPU_RGBA32I:
      return GL_RGBA32I;
    case GPU_RGBA32F:
      return GL_RGBA32F;
    case GPU_RGBA16UI:
      return GL_RGBA16UI;
    case GPU_RGBA16I:
      return GL_RGBA16I;
    case GPU_RGBA16F:
      return GL_RGBA16F;
    case GPU_RGBA16:
      return GL_RGBA16;
    case GPU_RG8UI:
      return GL_RG8UI;
    case GPU_RG8I:
      return GL_RG8I;
    case GPU_RG8:
      return GL_RG8;
    case GPU_RG32UI:
      return GL_RG32UI;
    case GPU_RG32I:
      return GL_RG32I;
    case GPU_RG32F:
      return GL_RG32F;
    case GPU_RG16UI:
      return GL_RG16UI;
    case GPU_RG16I:
      return GL_RG16I;
    case GPU_RG16F:
      return GL_RG16F;
    case GPU_RG16:
      return GL_RG16;
    case GPU_R8UI:
      return GL_R8UI;
    case GPU_R8I:
      return GL_R8I;
    case GPU_R8:
      return GL_R8;
    case GPU_R32UI:
      return GL_R32UI;
    case GPU_R32I:
      return GL_R32I;
    case GPU_R32F:
      return GL_R32F;
    case GPU_R16UI:
      return GL_R16UI;
    case GPU_R16I:
      return GL_R16I;
    case GPU_R16F:
      return GL_R16F;
    case GPU_R16:
      return GL_R16;
    /* Special formats texture & renderbuffer */
    case GPU_R11F_G11F_B10F:
      return GL_R11F_G11F_B10F;
    case GPU_DEPTH32F_STENCIL8:
      return GL_DEPTH32F_STENCIL8;
    case GPU_DEPTH24_STENCIL8:
      return GL_DEPTH24_STENCIL8;
    case GPU_SRGB8_A8:
      return GL_SRGB8_ALPHA8;
    /* Texture only format */
    case GPU_RGB16F:
      return GL_RGB16F;
    /* Special formats texture only */
    case GPU_SRGB8_A8_DXT1:
      return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT;
    case GPU_SRGB8_A8_DXT3:
      return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT;
    case GPU_SRGB8_A8_DXT5:
      return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT;
    case GPU_RGBA8_DXT1:
      return GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
    case GPU_RGBA8_DXT3:
      return GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
    case GPU_RGBA8_DXT5:
      return GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
    /* Depth Formats */
    case GPU_DEPTH_COMPONENT32F:
      return GL_DEPTH_COMPONENT32F;
    case GPU_DEPTH_COMPONENT24:
      return GL_DEPTH_COMPONENT24;
    case GPU_DEPTH_COMPONENT16:
      return GL_DEPTH_COMPONENT16;
    default:
      BLI_assert(!"Texture format incorrect or unsupported\n");
      return 0;
  }
}

inline GLenum to_gl_target(eGPUTextureType type)
{
  switch (type) {
    case GPU_TEXTURE_1D:
      return GL_TEXTURE_1D;
    case GPU_TEXTURE_1D_ARRAY:
      return GL_TEXTURE_1D_ARRAY;
    case GPU_TEXTURE_2D:
      return GL_TEXTURE_2D;
    case GPU_TEXTURE_2D_ARRAY:
      return GL_TEXTURE_2D_ARRAY;
    case GPU_TEXTURE_3D:
      return GL_TEXTURE_3D;
    case GPU_TEXTURE_CUBE:
      return GL_TEXTURE_CUBE_MAP;
    case GPU_TEXTURE_CUBE_ARRAY:
      return GL_TEXTURE_CUBE_MAP_ARRAY_ARB;
    case GPU_TEXTURE_BUFFER:
      return GL_TEXTURE_BUFFER;
    default:
      BLI_assert(0);
      return GL_TEXTURE_1D;
  }
}

inline GLenum to_gl_proxy(eGPUTextureType type)
{
  switch (type) {
    case GPU_TEXTURE_1D:
      return GL_PROXY_TEXTURE_1D;
    case GPU_TEXTURE_1D_ARRAY:
      return GL_PROXY_TEXTURE_1D_ARRAY;
    case GPU_TEXTURE_2D:
      return GL_PROXY_TEXTURE_2D;
    case GPU_TEXTURE_2D_ARRAY:
      return GL_PROXY_TEXTURE_2D_ARRAY;
    case GPU_TEXTURE_3D:
      return GL_PROXY_TEXTURE_3D;
    case GPU_TEXTURE_CUBE:
      return GL_PROXY_TEXTURE_CUBE_MAP;
    case GPU_TEXTURE_CUBE_ARRAY:
      return GL_PROXY_TEXTURE_CUBE_MAP_ARRAY_ARB;
    case GPU_TEXTURE_BUFFER:
    default:
      BLI_assert(0);
      return GL_TEXTURE_1D;
  }
}

inline GLenum swizzle_to_gl(const char swizzle)
{
  switch (swizzle) {
    default:
    case 'x':
    case 'r':
      return GL_RED;
    case 'y':
    case 'g':
      return GL_GREEN;
    case 'z':
    case 'b':
      return GL_BLUE;
    case 'w':
    case 'a':
      return GL_ALPHA;
    case '0':
      return GL_ZERO;
    case '1':
      return GL_ONE;
  }
}

inline GLenum to_gl(eGPUDataFormat format)
{
  switch (format) {
    case GPU_DATA_FLOAT:
      return GL_FLOAT;
    case GPU_DATA_INT:
      return GL_INT;
    case GPU_DATA_UNSIGNED_INT:
      return GL_UNSIGNED_INT;
    case GPU_DATA_UNSIGNED_BYTE:
      return GL_UNSIGNED_BYTE;
    case GPU_DATA_UNSIGNED_INT_24_8:
      return GL_UNSIGNED_INT_24_8;
    case GPU_DATA_10_11_11_REV:
      return GL_UNSIGNED_INT_10F_11F_11F_REV;
    default:
      BLI_assert(!"Unhandled data format");
      return GL_FLOAT;
  }
}

/* Definitely not complete, edit according to the gl specification. */
inline GLenum to_gl_data_format(eGPUTextureFormat format)
{
  /* You can add any of the available type to this list
   * For available types see GPU_texture.h */
  switch (format) {
    case GPU_R8I:
    case GPU_R8UI:
    case GPU_R16I:
    case GPU_R16UI:
    case GPU_R32I:
    case GPU_R32UI:
      return GL_RED_INTEGER;
    case GPU_RG8I:
    case GPU_RG8UI:
    case GPU_RG16I:
    case GPU_RG16UI:
    case GPU_RG32I:
    case GPU_RG32UI:
      return GL_RG_INTEGER;
    case GPU_RGBA8I:
    case GPU_RGBA8UI:
    case GPU_RGBA16I:
    case GPU_RGBA16UI:
    case GPU_RGBA32I:
    case GPU_RGBA32UI:
      return GL_RGBA_INTEGER;
    case GPU_R8:
    case GPU_R16:
    case GPU_R16F:
    case GPU_R32F:
      return GL_RED;
    case GPU_RG8:
    case GPU_RG16:
    case GPU_RG16F:
    case GPU_RG32F:
      return GL_RG;
    case GPU_R11F_G11F_B10F:
    case GPU_RGB16F:
      return GL_RGB;
    case GPU_RGBA8:
    case GPU_SRGB8_A8:
    case GPU_RGBA16:
    case GPU_RGBA16F:
    case GPU_RGBA32F:
      return GL_RGBA;
    case GPU_DEPTH24_STENCIL8:
    case GPU_DEPTH32F_STENCIL8:
      return GL_DEPTH_STENCIL;
    case GPU_DEPTH_COMPONENT16:
    case GPU_DEPTH_COMPONENT24:
    case GPU_DEPTH_COMPONENT32F:
      return GL_DEPTH_COMPONENT;
    default:
      BLI_assert(!"Texture format incorrect or unsupported\n");
      return 0;
  }
}

/* Assume Unorm / Float target. Used with glReadPixels. */
inline GLenum channel_len_to_gl(int channel_len)
{
  switch (channel_len) {
    case 1:
      return GL_RED;
    case 2:
      return GL_RG;
    case 3:
      return GL_RGB;
    case 4:
      return GL_RGBA;
    default:
      BLI_assert(!"Wrong number of texture channels");
      return GL_RED;
  }
}

}  // namespace gpu
}  // namespace blender