#pragma once
#include "paddle/framework/op_registry.h"
#include "paddle/operators/nccl/nccl_gpu_common.h"

#include <string.h>

namespace paddle {
namespace operators {


template<typename Type>
class NCCLTypeWrapper;

template<>
class NCCLTypeWrapper<float> {
  static const ncclDataType_t type = ncclFloat;
};

template<>
class NCCLTypeWrapper<double> {
  static const ncclDataType_t type = ncclDouble;
};



template<typename T>
class NCCLAllReduceKernel : public framework::OpKernel {
public:
  void Compute(const framework::ExecutionContext& ctx) const override {
    auto ins = ctx.MultiInput<Tensor>("X");
    auto outs = ctx.MultiOutput<Tensor>("Out");
    std::string reduction = ctx.Attr<std::string>("reduction");
    ncclRedOp_t op_type;
    if (reduction == "ncclSum") {
      op_type = ncclSum;
    } else if (reduction == "ncclProd") {
      op_type = ncclProd;
    } else if (reduction == "ncclMin") {
      op_type = ncclMin;
    } else (reduction == "ncclMax") {
      op_type = ncclMax;
    }

    auto dev_ctx = ctx.device_context();

    for( size_t i=0; i < ins.size(); ++i) {
      ncclAllReduce(ins[i]->data<T>(),
                    outs[i]->mutable_data<T>(),
                    outs[i]->numel() * sizeof(T),
                    NCCLTypeWrapper<T>::type,
                    op_type,
                    comm,
                    stream);
    }
  }
};


}
}