// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/mus/public/cpp/gles2_context.h"

#include <stddef.h>
#include <stdint.h>

#include <utility>

#include "components/mus/common/gpu_service.h"
#include "components/mus/public/cpp/lib/command_buffer_client_impl.h"
#include "components/mus/public/interfaces/command_buffer.mojom.h"
#include "components/mus/public/interfaces/gpu_service.mojom.h"
#include "gpu/command_buffer/client/gles2_cmd_helper.h"
#include "gpu/command_buffer/client/shared_memory_limits.h"
#include "gpu/command_buffer/client/transfer_buffer.h"
#include "gpu/ipc/client/command_buffer_proxy_impl.h"
#include "mojo/public/cpp/system/core.h"
#include "services/shell/public/cpp/connector.h"
#include "url/gurl.h"

namespace mus {

GLES2Context::GLES2Context() {}

GLES2Context::~GLES2Context() {}

bool GLES2Context::Initialize(const std::vector<int32_t>& attribs,
                              shell::Connector* connector) {
  gpu::CommandBuffer* command_buffer = nullptr;
  gpu::GpuControl* gpu_control = nullptr;
  // TODO(penghuang): Use type gpu::gles2::ContextCreationAttribHelper for
  // attribs.
  if (!mus::GpuService::UseChromeGpuCommandBuffer()) {
    mojom::GpuPtr gpu;
    connector->ConnectToInterface("mojo:mus", &gpu);
    mojom::CommandBufferPtr command_buffer_ptr;
    gpu->CreateOffscreenGLES2Context(GetProxy(&command_buffer_ptr));
    command_buffer_client_impl_.reset(
        new CommandBufferClientImpl(attribs, std::move(command_buffer_ptr)));
    if (!command_buffer_client_impl_->Initialize())
      return false;
    command_buffer = command_buffer_client_impl_.get();
    gpu_control = command_buffer_client_impl_.get();
  } else {
    scoped_refptr<gpu::GpuChannelHost> gpu_channel_host =
        GpuService::GetInstance()->EstablishGpuChannelSync();
    if (!gpu_channel_host)
      return false;
    gpu::SurfaceHandle surface_handle = gfx::kNullAcceleratedWidget;
    // TODO(penghuang): support shared group.
    gpu::CommandBufferProxyImpl* shared_command_buffer = nullptr;
    gpu::GpuStreamId stream_id = gpu::GpuStreamId::GPU_STREAM_DEFAULT;
    gpu::GpuStreamPriority stream_priority = gpu::GpuStreamPriority::NORMAL;
    gpu::gles2::ContextCreationAttribHelper attributes;
    // TODO(penghuang): figure a useful active_url.
    GURL active_url;
    scoped_refptr<base::SingleThreadTaskRunner> task_runner =
        base::ThreadTaskRunnerHandle::Get();
    if (!attributes.Parse(attribs))
      return false;
    command_buffer_proxy_impl_ = gpu::CommandBufferProxyImpl::Create(
        std::move(gpu_channel_host), surface_handle, shared_command_buffer,
        stream_id, stream_priority, attributes, active_url,
        std::move(task_runner));
    if (!command_buffer_proxy_impl_)
      return false;
    command_buffer = command_buffer_proxy_impl_.get();
    gpu_control = command_buffer_proxy_impl_.get();
  }

  constexpr gpu::SharedMemoryLimits default_limits;
  gles2_helper_.reset(new gpu::gles2::GLES2CmdHelper(command_buffer));
  if (!gles2_helper_->Initialize(default_limits.command_buffer_size))
    return false;
  gles2_helper_->SetAutomaticFlushes(false);
  transfer_buffer_.reset(new gpu::TransferBuffer(gles2_helper_.get()));
  gpu::Capabilities capabilities = gpu_control->GetCapabilities();
  bool bind_generates_resource =
      !!capabilities.bind_generates_resource_chromium;
  // TODO(piman): Some contexts (such as compositor) want this to be true, so
  // this needs to be a public parameter.
  bool lose_context_when_out_of_memory = false;
  bool support_client_side_arrays = false;
  implementation_.reset(new gpu::gles2::GLES2Implementation(
      gles2_helper_.get(), NULL, transfer_buffer_.get(),
      bind_generates_resource, lose_context_when_out_of_memory,
      support_client_side_arrays, gpu_control));
  if (!implementation_->Initialize(default_limits.start_transfer_buffer_size,
                                   default_limits.min_transfer_buffer_size,
                                   default_limits.max_transfer_buffer_size,
                                   default_limits.mapped_memory_reclaim_limit))
    return false;
  return true;
}

// static
std::unique_ptr<GLES2Context> GLES2Context::CreateOffscreenContext(
    const std::vector<int32_t>& attribs,
    shell::Connector* connector) {
  std::unique_ptr<GLES2Context> gles2_context(new GLES2Context);
  if (!gles2_context->Initialize(attribs, connector))
    gles2_context.reset();
  return gles2_context;
}

}  // namespace mus