#pragma once

#include <c10/core/GeneratorImpl.h>
#include <ATen/core/Generator.h>

// TODO: this file should be in ATen/cuda, not top level

namespace at {

struct TORCH_CUDA_API CUDAGenerator : public c10::GeneratorImpl {
  // Constructors
  CUDAGenerator(DeviceIndex device_index = -1);
  ~CUDAGenerator() = default;

  // CUDAGenerator methods
  std::shared_ptr<CUDAGenerator> clone() const;
  void set_current_seed(uint64_t seed) override;
  uint64_t current_seed() const override;
  uint64_t seed() override;
  void set_philox_offset_per_thread(uint64_t offset);
  uint64_t philox_offset_per_thread();
  std::pair<uint64_t, uint64_t> philox_engine_inputs(uint64_t increment);
  static DeviceType device_type();

private:
  CUDAGenerator* clone_impl() const override;
  uint64_t seed_ = default_rng_seed_val;
  uint64_t philox_offset_per_thread_ = 0;
};

namespace cuda {
namespace detail {

  TORCH_CUDA_API const Generator& getDefaultCUDAGenerator(DeviceIndex device_index = -1);
  TORCH_CUDA_API Generator createCUDAGenerator(DeviceIndex device_index = -1);

} // namespace detail
} // namespace cuda
} // namespace at

