// Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
//
// 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.

#include <vector>
#include "lite/backends/opencl/cl_include.h"
#include "lite/core/kernel.h"
#include "lite/core/op_registry.h"
#include "lite/kernels/opencl/image_helper.h"
#include "lite/operators/op_params.h"
#include "lite/utils/replace_stl/stream.h"
#include "lite/utils/string.h"

namespace paddle {
namespace lite {
namespace kernels {
namespace opencl {

class FcCompute
    : public KernelLite<TARGET(kOpenCL), PRECISION(kFloat), DATALAYOUT(kNCHW)> {
 public:
  using param_t = operators::FcParam;

  void PrepareForRun() override {}

  void ReInitWhenNeeded() override {
    fc_param_ = param_.get_mutable<param_t>();
    const auto x_dims = fc_param_->input->dims();
    if ((!first_epoch_for_reinit_ && x_dims != last_x_dims_) ||
        first_epoch_for_reinit_) {
      last_x_dims_ = x_dims;
      first_epoch_for_reinit_ = false;

      // compute m,n,k
      const auto w_dims = fc_param_->w->dims();
      CHECK_GE(x_dims.size(), 2UL);
      CHECK_GE(w_dims.size(), 2UL);
      CHECK_EQ(fc_param_->output->dims().size(), 2UL);

      m_ = x_dims.Slice(0, fc_param_->in_num_col_dims).production();
      k_ = x_dims.Slice(fc_param_->in_num_col_dims, x_dims.size()).production();
      n_ = w_dims[1];
      CHECK_EQ(k_, static_cast<int>(w_dims[0]));

#ifndef LITE_SHUTDOWN_LOG
      VLOG(4) << "x_dims:" << x_dims[0] << " " << x_dims[1] << " " << x_dims[2]
              << " " << x_dims[3];
      VLOG(4) << "w_dims:" << w_dims[0] << " " << w_dims[1] << " " << w_dims[2]
              << " " << w_dims[3];
      VLOG(4) << "m_: " << m_ << " n_: " << n_ << " k_: " << k_;
#endif

      // choose kernel
      if (m_ == 1) {  // gemv
        kernel_func_name_ = "fc_gemv_1x4";
      } else {  // gemm
        kernel_func_name_ = "fc_gemm_4x4";
      }
#ifndef LITE_SHUTDOWN_LOG
      VLOG(1) << "kernel_func_name_:" << kernel_func_name_;
#endif

      if (fc_param_->activation_type == "relu") {
        build_options_ += "-DRELU";
      }

      auto& context = ctx_->As<OpenCLContext>();
      context.cl_context()->AddKernel(kernel_func_name_,
                                      "buffer/fc_kernel.cl",
                                      build_options_,
                                      time_stamp_);
      STL::stringstream kernel_key;
      kernel_key << kernel_func_name_ << build_options_ << time_stamp_;
      kernel_ = context.cl_context()->GetKernel(kernel_key.str());

      // compute global work size
      GetGlobalWorkSize();
    }
  }

  void GetGlobalWorkSize() {
    if (m_ == 1) {  // gemv
      global_work_size_ = cl::NDRange{static_cast<size_t>((n_ + 3) / 4)};
    } else {  // gemm
      global_work_size_ = cl::NDRange{static_cast<size_t>((m_ + 3) / 4),
                                      static_cast<size_t>((n_ + 3) / 4)};
    }
  }

  void Run() override {
    auto* x_buf = fc_param_->input->data<float, cl::Buffer>();
    auto* w_buf = fc_param_->w->data<float, cl::Buffer>();
    auto* bias_buf = fc_param_->bias->data<float, cl::Buffer>();
    auto* out_buf =
        fc_param_->output->mutable_data<float, cl::Buffer>(TARGET(kOpenCL));

    auto kernel = kernel_;
    cl_int status;
    status = kernel.setArg(0, *x_buf);
    CL_CHECK_FATAL(status);
    status = kernel.setArg(1, *w_buf);
    CL_CHECK_FATAL(status);
    status = kernel.setArg(2, *bias_buf);
    CL_CHECK_FATAL(status);
    status = kernel.setArg(3, *out_buf);
    CL_CHECK_FATAL(status);
    status = kernel.setArg(4, static_cast<const int>(m_));
    CL_CHECK_FATAL(status);
    status = kernel.setArg(5, static_cast<const int>(n_));
    CL_CHECK_FATAL(status);
    status = kernel.setArg(6, static_cast<const int>(k_));
    CL_CHECK_FATAL(status);

    auto& context = ctx_->As<OpenCLContext>();
    CHECK(context.cl_context() != nullptr);
    event_ = std::shared_ptr<cl::Event>(new cl::Event);
    status = context.cl_context()->GetCommandQueue().enqueueNDRangeKernel(
        kernel,
        cl::NullRange,
        global_work_size_,
        cl::NullRange,
        nullptr,
        event_.get());
    CL_CHECK_FATAL(status);
    context.cl_wait_list()->emplace(out_buf, event_);
  }

 private:
  int m_, n_, k_;
  param_t* fc_param_{nullptr};
  std::string kernel_func_name_{};
  std::string build_options_{"-DCL_DTYPE_float "};
  std::string time_stamp_{GetTimeStamp()};
  bool first_epoch_for_reinit_{true};
  DDim last_x_dims_;
  cl::NDRange global_work_size_;
  cl::Kernel kernel_;
  std::shared_ptr<cl::Event> event_{nullptr};
};

}  // namespace opencl
}  // namespace kernels
}  // namespace lite
}  // namespace paddle

REGISTER_LITE_KERNEL(
    fc, kOpenCL, kFloat, kNCHW, paddle::lite::kernels::opencl::FcCompute, def)
    .BindInput("Input", {LiteType::GetTensorTy(TARGET(kOpenCL))})
    .BindInput("Bias", {LiteType::GetTensorTy(TARGET(kOpenCL))})
    .BindInput("W", {LiteType::GetTensorTy(TARGET(kOpenCL))})
    .BindOutput("Out", {LiteType::GetTensorTy(TARGET(kOpenCL))})
    .Finalize();
