/**
 * Copyright 2019 Huawei Technologies Co., Ltd
 *
 * 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.
 */

#ifndef MINDSPORE_CCSRC_DEVICE_GPU_BLOCKING_QUEUE_H_
#define MINDSPORE_CCSRC_DEVICE_GPU_BLOCKING_QUEUE_H_

#include <unistd.h>
#include <cuda_runtime_api.h>
#include <iostream>
#include <memory>
#include <mutex>
#include <cstring>
#include <string>
#include <condition_variable>
#include <functional>

namespace mindspore {
namespace device {
enum BlockQueueStatus_T : int { SUCCESS = 0, QUEUE_NOT_EXIST, HANDLE_NOT_EXIST, ERROR_INPUT, INTERNAL_ERROR, TIMEOUT };

class GpuQueue {
 public:
  GpuQueue(void* addr, size_t feature_size, size_t label_size, size_t capacity);
  virtual ~GpuQueue();

  void RegisterRelease(const std::function<void(void*)>& func) { host_release_ = func; }

  inline bool IsEmpty() const { return head_ == tail_; }
  inline bool IsFull() const { return head_ == ((tail_ + 1) % (capacity_)); }

  BlockQueueStatus_T Push(void* feature_addr, size_t feature_size, void* label_addr, size_t label_size);
  BlockQueueStatus_T Front(void** feature_addr, size_t* feature_size, void** label_addr, size_t* label_size) const;
  BlockQueueStatus_T Pop();
  bool Destroy();

 private:
  struct NodeInfo {
    std::unique_ptr<cudaEvent_t> event_;
    void* host_feature_addr_;
    void* host_label_addr_;
  };

  void* buffer_;
  size_t head_;
  size_t tail_;
  size_t feature_size_;
  size_t label_size_;
  size_t capacity_;
  cudaStream_t stream_;
  std::unique_ptr<NodeInfo[]> node_info_;
  std::function<void(void*)> host_release_;

  GpuQueue(const GpuQueue&) = delete;
  GpuQueue& operator=(const GpuQueue&) = delete;
};

class BlockingQueue {
 public:
  BlockingQueue() : queue_(nullptr) {}
  ~BlockingQueue() = default;

  BlockQueueStatus_T Create(void* addr, size_t feature_size, size_t label_size, size_t capacity);
  void RegisterRelease(const std::function<void(void*)>& func);
  BlockQueueStatus_T Push(void* feature_addr, size_t feature_size, void* label_addr, size_t label_size,
                          unsigned int timeout_in_sec);
  BlockQueueStatus_T Front(void** feature_addr, size_t* feature_size, void** label_addr, size_t* label_size);
  BlockQueueStatus_T Pop();
  bool Destroy();

 private:
  std::mutex mutex_;
  std::condition_variable not_full_cond_;
  std::condition_variable not_empty_cond_;
  std::shared_ptr<GpuQueue> queue_;
};
}  // namespace device
}  // namespace mindspore

#endif  // MINDSPORE_CCSRC_DEVICE_GPU_BLOCKING_QUEUE_H_