/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
    http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. */

#pragma once

#include "paddle/platform/enforce.h"
#include "paddle/platform/place.h"

#ifndef PADDLE_ONLY_CPU
#include <thrust/device_ptr.h>
#include <thrust/random.h>
#include "paddle/platform/dynload/cublas.h"
#include "paddle/platform/dynload/cudnn.h"
#include "paddle/platform/gpu_info.h"
#define EIGEN_USE_GPU
#endif
#include <memory>
#include "paddle/platform/place.h"
#include "unsupported/Eigen/CXX11/Tensor"

namespace paddle {
namespace platform {

class DeviceContext {
 public:
  virtual ~DeviceContext() {}
  virtual Place GetPlace() const = 0;

  template <typename DeviceType>
  DeviceType* get_eigen_device() const;
};

class CPUDeviceContext : public DeviceContext {
 public:
  CPUDeviceContext();
  explicit CPUDeviceContext(CPUPlace place, int rand_seed = 0);
  virtual ~CPUDeviceContext() {}

  Eigen::DefaultDevice* eigen_device() const;

  std::minstd_rand& rand_engine();

  Place GetPlace() const override;

 private:
  int rand_seed_;
  std::unique_ptr<std::minstd_rand> rand_engine_;
  std::unique_ptr<Eigen::DefaultDevice> eigen_device_;
};

#ifndef PADDLE_ONLY_CPU
class EigenCudaStreamDevice;

class CUDADeviceContext : public DeviceContext {
 public:
  explicit CUDADeviceContext(GPUPlace place, uint64_t rand_seed = 0);
  virtual ~CUDADeviceContext();

  /*! \brief  Wait for all operations completion in the stream. */
  void Wait() const;

  /*! \brief  Return place in the device context. */
  Place GetPlace() const override;

  /*! \brief  Return eigen device in the device context. */
  Eigen::GpuDevice* eigen_device() const;

  // clang-format off
  /*! \brief  Return cublas handle in the device context. */
  cublasHandle_t    cublas_handle();

  /*! \brief  Return cudnn  handle in the device context. */
  cudnnHandle_t     cudnn_handle();

  thrust::minstd_rand& CPUDeviceContext::rand_engine();

  /*! \brief  Return cuda stream in the device context. */
  cudaStream_t      stream();
  // clang-format on

 private:
  GPUPlace place_;

  std::unique_ptr<Eigen::GpuDevice> eigen_device_;
  std::unique_ptr<EigenCudaStreamDevice> eigen_stream_;

  uint64_t rand_seed_;
  std::unique_ptr<thrust::minstd_rand> rand_engine_;

  // clang-format off
  cudaStream_t       stream_{nullptr};
  cudnnHandle_t      cudnn_handle_{nullptr};
  cublasHandle_t     cublas_handle_{nullptr};
  // clang-format on
};

#endif

}  // namespace platform
}  // namespace paddle