// =================================================================================================
// This file is part of the CLBlast project. The project is licensed under Apache Version 2.0. This
// project loosely follows the Google C++ styleguide and uses a tab-size of two spaces and a max-
// width of 100 characters per line.
//
// Author(s):
//   Cedric Nugteren <www.cedricnugteren.nl>
//
// This file implements the Xconvgemm class (see the header for information about the class).
//
// =================================================================================================

#include <string>
#include <vector>
#include <assert.h>

#include "routines/levelx/xconvgemm.hpp"
#include "routines/levelx/xim2col.hpp"

namespace clblast {
// =================================================================================================

// Constructor: forwards to base class constructor
template <typename T>
Xconvgemm<T>::Xconvgemm(Queue &queue, EventPointer event, const std::string &name,
                        const ConvGemmMethod method):
    Routine(queue, event, name, {"Xconvgemm"},
        PrecisionValue<T>(), {}, {
            (method == ConvGemmMethod::kWithIm2Col) ? "#define CONVGEMM_WITH_IM2COL\n" : "",
            #include "../../kernels/level3/level3.opencl"
            , // separated in multiple parts to prevent C1091 in MSVC 2013
            #include "../../kernels/level3/xgemm_direct_part1.opencl"
            #include "../../kernels/level3/xgemm_direct_part2.opencl"
            #include "../../kernels/level3/xgemm_direct_part3.opencl"
            , // separated in multiple parts to prevent C1091 in MSVC 2013
            #include "../../kernels/levelx/xconvgemm_part1.opencl"
            #include "../../kernels/levelx/xconvgemm_part2.opencl"
        }),
    method_(method) {
}

// =================================================================================================

template <typename T>
void Xconvgemm<T>::DoConvgemm(const KernelMode kernel_mode,
                              const size_t channels, const size_t height, const size_t width,
                              const size_t kernel_h, const size_t kernel_w, const size_t pad_h,
                              const size_t pad_w, const size_t stride_h, const size_t stride_w,
                              const size_t dilation_h, const size_t dilation_w,
                              const size_t num_kernels, const size_t batch_count,
                              const Buffer<T> &im_buffer, const size_t im_offset,
                              const Buffer<T> &kernel_buffer, const size_t kernel_offset,
                              const Buffer<T> &result_buffer, const size_t result_offset) {

  // Tests for a valid batch count
  if (batch_count == 0) {
    throw BLASError(StatusCode::kInvalidBatchCount);
  }

  // Makes sure all dimensions are larger than zero
  if ((channels == 0) || (height == 0) || (width == 0) || (num_kernels == 0)) {
    throw BLASError(StatusCode::kInvalidDimension);
  }

  // Sets the output height and width
  const auto size_h = height + 2 * pad_h;
  const auto padding_h = dilation_h * (kernel_h - 1) + 1;
  const auto output_h = (size_h >= padding_h) ? (size_h - padding_h) / stride_h + 1 : 1;
  const auto size_w = width + 2 * pad_w;
  const auto padding_w = dilation_w * (kernel_w - 1) + 1;
  const auto output_w = (size_w >= padding_w) ? (size_w - padding_w) / stride_w + 1 : 1;

  // Sets other useful variables
  const auto patch_size = kernel_h * kernel_w * channels;
  const auto num_patches = output_h * output_w;

  // Possible approach: im2col + GEMM
  //      result = GEMM(im2col(image), kernel)
  auto col_buffer = Buffer<T>(context_, 0); // nullptr, will be optionally created later
  if (method_ == ConvGemmMethod::kWithIm2Col) {

    // Temporary col matrix
    const auto col_size = (method_ == ConvGemmMethod::kWithIm2Col) ? patch_size * num_patches * batch_count : 1;
    col_buffer = Buffer<T>(context_, col_size);

    // Loops over each batch
    for (auto batch_id = size_t{0}; batch_id < batch_count; ++batch_id) {

      // im2col
      const auto im_batch_offset = batch_id * channels * height * width + im_offset;
      const auto col_batch_offset = batch_id * patch_size * num_patches;
      auto im2col_event = Event();
      auto im2col = Xim2col<T>(queue_, im2col_event.pointer());
      im2col.DoIm2col(kernel_mode,
                      channels, height, width, kernel_h, kernel_w,
                      pad_h, pad_w, stride_h, stride_w, dilation_h, dilation_w,
                      im_buffer, im_batch_offset,
                      col_buffer, col_batch_offset);
      im2col_event.WaitForCompletion();
    }
  }

  // Strided batched GEMM: C (result) = alpha (1) * A (col) * B (kernel) + beta (0) * C (result)
  const auto col_stride = patch_size * num_patches;
  const auto result_stride = num_kernels * output_h * output_w;

  // Tests the matrices for validity
  TestMatrixB(patch_size, num_kernels, kernel_buffer, kernel_offset, patch_size);
  for (auto batch = size_t{0}; batch < batch_count; ++batch) {
    if (method_ == ConvGemmMethod::kWithIm2Col) {
      TestMatrixA(num_patches, patch_size, col_buffer, col_stride * batch, num_patches);
    }
    else {
      // TODO: check for valid image tensor
    }
    TestMatrixC(num_patches, num_kernels, result_buffer, result_offset + result_stride * batch, num_patches);
  }

  // Retrieves the proper XgemmDirect kernel from the compiled binary
  const std::string kernel_name = (method_ == ConvGemmMethod::kWithIm2Col)
                                ? "Xconvgemm"
                                : (kernel_mode == KernelMode::kConvolution)
                                ? "XconvgemmFlip"
                                : "XconvgemmNormal";
  auto kernel = Kernel(program_, kernel_name);

  // Sets the kernel arguments
  kernel.SetArgument(0, static_cast<int>(num_patches));
  kernel.SetArgument(1, static_cast<int>(num_kernels));
  kernel.SetArgument(2, static_cast<int>(patch_size));
  kernel.SetArgument(3, kernel_buffer());
  kernel.SetArgument(4, static_cast<int>(kernel_offset));
  kernel.SetArgument(5, result_buffer());
  kernel.SetArgument(6, static_cast<int>(result_offset));
  kernel.SetArgument(7, static_cast<int>(result_stride));
  if (method_ == ConvGemmMethod::kWithIm2Col) {
    kernel.SetArgument(8, col_buffer());
    kernel.SetArgument(9, static_cast<int>(0));
    kernel.SetArgument(10, static_cast<int>(col_stride));
  }
  if (method_ == ConvGemmMethod::kSingleKernel) {
    kernel.SetArgument(8, im_buffer());
    kernel.SetArgument(9, static_cast<int>(im_offset));
    kernel.SetArgument(10, static_cast<int>(height));
    kernel.SetArgument(11, static_cast<int>(width));
    kernel.SetArgument(12, static_cast<int>(channels));
    kernel.SetArgument(13, static_cast<int>(kernel_h));
    kernel.SetArgument(14, static_cast<int>(kernel_w));
    kernel.SetArgument(15, static_cast<int>(pad_h));
    kernel.SetArgument(16, static_cast<int>(pad_w));
    kernel.SetArgument(17, static_cast<int>(stride_h));
    kernel.SetArgument(18, static_cast<int>(stride_w));
    kernel.SetArgument(19, static_cast<int>(dilation_h));
    kernel.SetArgument(20, static_cast<int>(dilation_w));
    kernel.SetArgument(21, static_cast<int>(output_h));
    kernel.SetArgument(22, static_cast<int>(output_w));
  }

  // Computes the global and local thread sizes
  const auto m_ceiled = Ceil(num_patches, db_["WGD"]);
  const auto n_ceiled = Ceil(num_kernels, db_["WGD"]);
  const auto global = std::vector<size_t>{
      (m_ceiled * db_["MDIMCD"]) / db_["WGD"],
      (n_ceiled * db_["NDIMCD"]) / db_["WGD"],
      batch_count
  };
  const auto local = std::vector<size_t>{db_["MDIMCD"], db_["NDIMCD"], 1};

  // Launches the kernel
  RunKernel(kernel, queue_, device_, global, local, event_);
}

// =================================================================================================

// Compiles the templated class
template class Xconvgemm<half>;
template class Xconvgemm<float>;
template class Xconvgemm<double>;
template class Xconvgemm<float2>;
template class Xconvgemm<double2>;

// =================================================================================================
} // namespace clblast