// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ash/utility/layer_util.h"

#include "base/functional/bind.h"
#include "base/memory/scoped_refptr.h"
#include "components/viz/common/frame_sinks/copy_output_request.h"
#include "components/viz/common/frame_sinks/copy_output_result.h"
#include "gpu/command_buffer/client/client_shared_image.h"
#include "third_party/khronos/GLES2/gl2.h"
#include "ui/compositor/layer.h"
#include "ui/gfx/geometry/size.h"

namespace ash {
namespace {

void CopyCopyOutputResultToLayer(
    std::unique_ptr<viz::CopyOutputResult> copy_result,
    ui::Layer* target_layer) {
  DCHECK(!copy_result->IsEmpty());
  DCHECK_EQ(copy_result->format(), viz::CopyOutputResult::Format::RGBA);
  DCHECK_EQ(copy_result->destination(),
            viz::CopyOutputResult::Destination::kSharedImage);

  scoped_refptr<gpu::ClientSharedImage> shared_image =
      copy_result->GetSharedImage();
  viz::TransferableResource transferable_resource =
      viz::TransferableResource::Make(
          shared_image, viz::TransferableResource::ResourceSource::kUI,
          gpu::SyncToken(), /*override=*/{.color_space = gfx::ColorSpace()});
  viz::ReleaseCallback release_callback =
      copy_result->TakeSharedImageOwnership();
  DCHECK(release_callback);
  target_layer->SetTransferableResource(
      transferable_resource, std::move(release_callback), target_layer->size());
}

void CopyToNewLayerOnCopyRequestFinished(
    LayerCopyCallback layer_copy_callback,
    const gfx::Size& layer_size,
    std::unique_ptr<viz::CopyOutputResult> copy_result) {
  if (!copy_result || copy_result->IsEmpty()) {
    if (layer_copy_callback) {
      std::move(layer_copy_callback).Run(nullptr);
    }
    return;
  }

  auto copy_layer =
      CreateLayerFromCopyOutputResult(std::move(copy_result), layer_size);
  std::move(layer_copy_callback).Run(std::move(copy_layer));
}

void CopyToLayerOnCopyRequestFinished(
    GetTargetLayerCallback get_target_layer_callback,
    std::unique_ptr<viz::CopyOutputResult> copy_result) {
  if (get_target_layer_callback.IsCancelled())
    return;

  if (!copy_result || copy_result->IsEmpty())
    return;

  ui::Layer* layer = nullptr;
  std::move(get_target_layer_callback).Run(&layer);
  if (!layer)
    return;

  CopyCopyOutputResultToLayer(std::move(copy_result), layer);
}

}  // namespace

std::unique_ptr<ui::Layer> CreateLayerFromCopyOutputResult(
    std::unique_ptr<viz::CopyOutputResult> copy_result,
    const gfx::Size& layer_size) {
  auto copy_layer = std::make_unique<ui::Layer>(ui::LAYER_SOLID_COLOR);
  copy_layer->SetBounds(gfx::Rect(layer_size));
  CopyCopyOutputResultToLayer(std::move(copy_result), copy_layer.get());
  return copy_layer;
}

void CopyLayerContentToNewLayer(ui::Layer* layer, LayerCopyCallback callback) {
  auto new_callback = base::BindOnce(&CopyToNewLayerOnCopyRequestFinished,
                                     std::move(callback), layer->size());
  auto copy_request = std::make_unique<viz::CopyOutputRequest>(
      viz::CopyOutputRequest::ResultFormat::RGBA,
      viz::CopyOutputRequest::ResultDestination::kSharedImage,
      std::move(new_callback));
  gfx::Rect bounds(layer->size());
  copy_request->set_area(bounds);
  copy_request->set_result_selection(bounds);
  layer->RequestCopyOfOutput(std::move(copy_request));
}

void CopyLayerContentToLayer(ui::Layer* layer,
                             GetTargetLayerCallback callback) {
  auto new_callback =
      base::BindOnce(&CopyToLayerOnCopyRequestFinished, std::move(callback));
  auto copy_request = std::make_unique<viz::CopyOutputRequest>(
      viz::CopyOutputRequest::ResultFormat::RGBA,
      viz::CopyOutputRequest::ResultDestination::kSharedImage,
      std::move(new_callback));
  gfx::Rect bounds(layer->size());
  copy_request->set_area(bounds);
  copy_request->set_result_selection(bounds);
  layer->RequestCopyOfOutput(std::move(copy_request));
}

}  // namespace ash