/* SPDX-FileCopyrightText: 2022 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

/** \file
 * \ingroup gpu
 */
#include "vk_context.hh"
#include "vk_debug.hh"

#include "vk_backend.hh"
#include "vk_framebuffer.hh"
#include "vk_immediate.hh"
#include "vk_memory.hh"
#include "vk_shader.hh"
#include "vk_shader_interface.hh"
#include "vk_state_manager.hh"
#include "vk_texture.hh"

#include "GHOST_C-api.h"

namespace blender::gpu {

VKContext::VKContext(void *ghost_window,
                     void *ghost_context,
                     render_graph::VKRenderGraph &render_graph)
    : render_graph(render_graph)
{
  ghost_window_ = ghost_window;
  ghost_context_ = ghost_context;

  state_manager = new VKStateManager();
  imm = new VKImmediate();

  /* For off-screen contexts. Default frame-buffer is empty. */
  VKFrameBuffer *framebuffer = new VKFrameBuffer("back_left");
  back_left = framebuffer;
  active_fb = framebuffer;

  compiler = new ShaderCompilerGeneric();
}

VKContext::~VKContext()
{
  if (surface_texture_) {
    GPU_texture_free(surface_texture_);
    surface_texture_ = nullptr;
  }
  VKBackend::get().device.context_unregister(*this);

  delete imm;
  imm = nullptr;

  delete compiler;
}

void VKContext::sync_backbuffer()
{
  if (ghost_context_) {
    VKDevice &device = VKBackend::get().device;
    if (!is_init_) {
      is_init_ = true;
      descriptor_pools_.init(device);
      device.init_dummy_buffer(*this);
    }
    descriptor_pools_.reset();
  }

  if (ghost_window_) {
    GHOST_VulkanSwapChainData swap_chain_data = {};
    GHOST_GetVulkanSwapChainFormat((GHOST_WindowHandle)ghost_window_, &swap_chain_data);

    const bool reset_framebuffer = swap_chain_format_ != swap_chain_data.format ||
                                   vk_extent_.width != swap_chain_data.extent.width ||
                                   vk_extent_.height != swap_chain_data.extent.height;
    if (reset_framebuffer) {
      if (has_active_framebuffer()) {
        deactivate_framebuffer();
      }
      if (surface_texture_) {
        GPU_texture_free(surface_texture_);
        surface_texture_ = nullptr;
      }
      surface_texture_ = GPU_texture_create_2d("back-left",
                                               swap_chain_data.extent.width,
                                               swap_chain_data.extent.height,
                                               1,
                                               to_gpu_format(swap_chain_data.format),
                                               GPU_TEXTURE_USAGE_ATTACHMENT,
                                               nullptr);

      back_left->attachment_set(GPU_FB_COLOR_ATTACHMENT0,
                                GPU_ATTACHMENT_TEXTURE(surface_texture_));

      back_left->bind(false);

      swap_chain_format_ = swap_chain_data.format;
      vk_extent_ = swap_chain_data.extent;
    }
  }
}

void VKContext::activate()
{
  /* Make sure no other context is already bound to this thread. */
  BLI_assert(is_active_ == false);

  is_active_ = true;

  sync_backbuffer();

  immActivate();
}

void VKContext::deactivate()
{
  immDeactivate();
  is_active_ = false;
}

void VKContext::begin_frame() {}

void VKContext::end_frame() {}

void VKContext::flush() {}

void VKContext::flush_render_graph()
{
  if (has_active_framebuffer()) {
    VKFrameBuffer &framebuffer = *active_framebuffer_get();
    if (framebuffer.is_rendering()) {
      framebuffer.rendering_end(*this);
    }
  }
  render_graph.submit();
}

void VKContext::finish() {}

void VKContext::memory_statistics_get(int *r_total_mem_kb, int *r_free_mem_kb)
{
  const VKDevice &device = VKBackend::get().device;
  device.memory_statistics_get(r_total_mem_kb, r_free_mem_kb);
}

/* -------------------------------------------------------------------- */
/** \name State manager
 * \{ */

VKStateManager &VKContext::state_manager_get() const
{
  return *static_cast<VKStateManager *>(state_manager);
}

void VKContext::debug_unbind_all_ubo()
{
  state_manager_get().uniform_buffer_unbind_all();
};

void VKContext::debug_unbind_all_ssbo()
{
  state_manager_get().storage_buffer_unbind_all();
};

/** \} */

/* -------------------------------------------------------------------- */
/** \name Frame-buffer
 * \{ */

void VKContext::activate_framebuffer(VKFrameBuffer &framebuffer)
{
  if (has_active_framebuffer()) {
    deactivate_framebuffer();
  }

  BLI_assert(active_fb == nullptr);
  active_fb = &framebuffer;
  framebuffer.update_size();
  framebuffer.update_srgb();
  framebuffer.rendering_reset();
}

VKFrameBuffer *VKContext::active_framebuffer_get() const
{
  return unwrap(active_fb);
}

bool VKContext::has_active_framebuffer() const
{
  return active_framebuffer_get() != nullptr;
}

void VKContext::deactivate_framebuffer()
{
  VKFrameBuffer *framebuffer = active_framebuffer_get();
  BLI_assert(framebuffer != nullptr);
  framebuffer->rendering_end(*this);
  active_fb = nullptr;
}

void VKContext::rendering_end()
{
  VKFrameBuffer *framebuffer = active_framebuffer_get();
  if (framebuffer) {
    framebuffer->rendering_end(*this);
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Pipeline
 * \{ */

void VKContext::update_pipeline_data(GPUPrimType primitive,
                                     VKVertexAttributeObject &vao,
                                     render_graph::VKPipelineData &r_pipeline_data)
{
  VKShader &vk_shader = unwrap(*shader);
  BLI_assert(vk_shader.is_graphics_shader());
  VKFrameBuffer &framebuffer = *active_framebuffer_get();
  update_pipeline_data(
      vk_shader,
      vk_shader.ensure_and_get_graphics_pipeline(primitive, vao, state_manager_get(), framebuffer),
      r_pipeline_data);
}

void VKContext::update_pipeline_data(render_graph::VKPipelineData &r_pipeline_data)
{
  VKShader &vk_shader = unwrap(*shader);
  BLI_assert(vk_shader.is_compute_shader());
  update_pipeline_data(vk_shader, vk_shader.ensure_and_get_compute_pipeline(), r_pipeline_data);
}

void VKContext::update_pipeline_data(VKShader &vk_shader,
                                     VkPipeline vk_pipeline,
                                     render_graph::VKPipelineData &r_pipeline_data)
{
  r_pipeline_data.vk_pipeline_layout = vk_shader.vk_pipeline_layout;
  r_pipeline_data.vk_pipeline = vk_pipeline;

  /* Update push constants. */
  r_pipeline_data.push_constants_data = nullptr;
  r_pipeline_data.push_constants_size = 0;
  const VKPushConstants::Layout &push_constants_layout =
      vk_shader.interface_get().push_constants_layout_get();
  vk_shader.push_constants.update(*this);
  if (push_constants_layout.storage_type_get() == VKPushConstants::StorageType::PUSH_CONSTANTS) {
    r_pipeline_data.push_constants_size = push_constants_layout.size_in_bytes();
    r_pipeline_data.push_constants_data = vk_shader.push_constants.data();
  }

  /* When using the push constant fallback we need to add a read access dependency to the uniform
   * buffer after the buffer has been updated.
   * NOTE: this alters the context instance variable `access_info_` which isn't clear from the API.
   */
  if (push_constants_layout.storage_type_get() == VKPushConstants::StorageType::UNIFORM_BUFFER) {
    access_info_.buffers.append(
        {vk_shader.push_constants.uniform_buffer_get()->vk_handle(), VK_ACCESS_UNIFORM_READ_BIT});
  }

  /* Update descriptor set. */
  r_pipeline_data.vk_descriptor_set = VK_NULL_HANDLE;
  if (vk_shader.has_descriptor_set()) {
    descriptor_set_.update(*this);
    r_pipeline_data.vk_descriptor_set = descriptor_set_get().active_descriptor_set()->vk_handle();
  }
}

render_graph::VKResourceAccessInfo &VKContext::update_and_get_access_info()
{
  access_info_.reset();
  state_manager_get().apply_bindings(*this, access_info_);
  return access_info_;
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Graphics pipeline
 * \{ */

void VKContext::swap_buffers_pre_callback(const GHOST_VulkanSwapChainData *swap_chain_data)
{
  VKContext *context = VKContext::get();
  BLI_assert(context);
  context->swap_buffers_pre_handler(*swap_chain_data);
}

void VKContext::swap_buffers_post_callback()
{
  VKContext *context = VKContext::get();
  BLI_assert(context);
  context->swap_buffers_post_handler();
}

void VKContext::swap_buffers_pre_handler(const GHOST_VulkanSwapChainData &swap_chain_data)
{
  VKFrameBuffer &framebuffer = *unwrap(back_left);
  VKTexture *color_attachment = unwrap(unwrap(framebuffer.color_tex(0)));

  render_graph::VKBlitImageNode::CreateInfo blit_image = {};
  blit_image.src_image = color_attachment->vk_image_handle();
  blit_image.dst_image = swap_chain_data.image;
  blit_image.filter = VK_FILTER_NEAREST;

  VkImageBlit &region = blit_image.region;
  region.srcOffsets[0] = {0, color_attachment->height_get() - 1, 0};
  region.srcOffsets[1] = {color_attachment->width_get(), 0, 1};
  region.srcSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
  region.srcSubresource.mipLevel = 0;
  region.srcSubresource.baseArrayLayer = 0;
  region.srcSubresource.layerCount = 1;

  region.dstOffsets[0] = {0, 0, 0};
  region.dstOffsets[1] = {
      int32_t(swap_chain_data.extent.width), int32_t(swap_chain_data.extent.height), 1};
  region.dstSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
  region.dstSubresource.mipLevel = 0;
  region.dstSubresource.baseArrayLayer = 0;
  region.dstSubresource.layerCount = 1;

  /* Swap chain commands are CPU synchronized at this moment, allowing to temporary add the swap
   * chain image as device resources. When we move towards GPU swap chain synchronization we need
   * to keep track of the swap chain image between frames. */
  VKDevice &device = VKBackend::get().device;
  device.resources.add_image(swap_chain_data.image,
                             1,
                             VK_IMAGE_LAYOUT_PRESENT_SRC_KHR,
                             render_graph::ResourceOwner::SWAP_CHAIN,
                             "SwapchainImage");

  framebuffer.rendering_end(*this);
  render_graph.add_node(blit_image);
  render_graph.submit_for_present(swap_chain_data.image);

  device.resources.remove_image(swap_chain_data.image);
#if 0
  device.debug_print();
#endif
  device.destroy_discarded_resources();
}

void VKContext::swap_buffers_post_handler()
{
  sync_backbuffer();
}

/** \} */

}  // namespace blender::gpu