// Copyright (c) OpenMMLab. All rights reserved
#include "deform_conv_cuda_kernel.cuh"
#include "pytorch_cuda_helper.hpp"

void deformable_im2col(Tensor data_im, Tensor data_offset, const int channels,
                       const int height, const int width, const int ksize_h,
                       const int ksize_w, const int pad_h, const int pad_w,
                       const int stride_h, const int stride_w,
                       const int dilation_h, const int dilation_w,
                       const int parallel_imgs, const int deformable_group,
                       Tensor data_col) {
  // num_axes should be smaller than block size
  // todo: check parallel_imgs is correctly passed in
  int height_col =
      (height + 2 * pad_h - (dilation_h * (ksize_h - 1) + 1)) / stride_h + 1;
  int width_col =
      (width + 2 * pad_w - (dilation_w * (ksize_w - 1) + 1)) / stride_w + 1;
  int num_kernels = channels * height_col * width_col * parallel_imgs;
  int channel_per_deformable_group = channels / deformable_group;

  AT_DISPATCH_FLOATING_TYPES_AND_HALF(
      data_im.scalar_type(), "deformable_im2col_gpu", ([&] {
        const scalar_t *data_im_ = data_im.data_ptr<scalar_t>();
        const scalar_t *data_offset_ = data_offset.data_ptr<scalar_t>();
        scalar_t *data_col_ = data_col.data_ptr<scalar_t>();

        deformable_im2col_gpu_kernel<<<GET_BLOCKS(num_kernels),
                                       THREADS_PER_BLOCK, 0,
                                       at::cuda::getCurrentCUDAStream()>>>(
            num_kernels, data_im_, data_offset_, height, width, ksize_h,
            ksize_w, pad_h, pad_w, stride_h, stride_w, dilation_h, dilation_w,
            channel_per_deformable_group, parallel_imgs, channels,
            deformable_group, height_col, width_col, data_col_);
      }));
  AT_CUDA_CHECK(cudaGetLastError());
}

void deformable_col2im(Tensor data_col, Tensor data_offset, const int channels,
                       const int height, const int width, const int ksize_h,
                       const int ksize_w, const int pad_h, const int pad_w,
                       const int stride_h, const int stride_w,
                       const int dilation_h, const int dilation_w,
                       const int parallel_imgs, const int deformable_group,
                       Tensor grad_im) {
  // todo: make sure parallel_imgs is passed in correctly
  int height_col =
      (height + 2 * pad_h - (dilation_h * (ksize_h - 1) + 1)) / stride_h + 1;
  int width_col =
      (width + 2 * pad_w - (dilation_w * (ksize_w - 1) + 1)) / stride_w + 1;
  int num_kernels =
      channels * ksize_h * ksize_w * height_col * width_col * parallel_imgs;
  int channel_per_deformable_group = channels / deformable_group;

  AT_DISPATCH_FLOATING_TYPES_AND_HALF(
      data_col.scalar_type(), "deformable_col2im_gpu", ([&] {
        const scalar_t *data_col_ = data_col.data_ptr<scalar_t>();
        const scalar_t *data_offset_ = data_offset.data_ptr<scalar_t>();
        scalar_t *grad_im_ = grad_im.data_ptr<scalar_t>();

        deformable_col2im_gpu_kernel<<<GET_BLOCKS(num_kernels),
                                       THREADS_PER_BLOCK, 0,
                                       at::cuda::getCurrentCUDAStream()>>>(
            num_kernels, data_col_, data_offset_, channels, height, width,
            ksize_h, ksize_w, pad_h, pad_w, stride_h, stride_w, dilation_h,
            dilation_w, channel_per_deformable_group, parallel_imgs,
            deformable_group, height_col, width_col, grad_im_);
      }));
  AT_CUDA_CHECK(cudaGetLastError());
}

void deformable_col2im_coord(
    Tensor data_col, Tensor data_im, Tensor data_offset, const int channels,
    const int height, const int width, const int ksize_h, const int ksize_w,
    const int pad_h, const int pad_w, const int stride_h, const int stride_w,
    const int dilation_h, const int dilation_w, const int parallel_imgs,
    const int deformable_group, Tensor grad_offset) {
  int height_col =
      (height + 2 * pad_h - (dilation_h * (ksize_h - 1) + 1)) / stride_h + 1;
  int width_col =
      (width + 2 * pad_w - (dilation_w * (ksize_w - 1) + 1)) / stride_w + 1;
  int num_kernels = height_col * width_col * 2 * ksize_h * ksize_w *
                    deformable_group * parallel_imgs;
  int channel_per_deformable_group =
      channels * ksize_h * ksize_w / deformable_group;

  AT_DISPATCH_FLOATING_TYPES_AND_HALF(
      data_col.scalar_type(), "deformable_col2im_coord_gpu", ([&] {
        const scalar_t *data_col_ = data_col.data_ptr<scalar_t>();
        const scalar_t *data_im_ = data_im.data_ptr<scalar_t>();
        const scalar_t *data_offset_ = data_offset.data_ptr<scalar_t>();
        scalar_t *grad_offset_ = grad_offset.data_ptr<scalar_t>();

        deformable_col2im_coord_gpu_kernel<<<
            GET_BLOCKS(num_kernels), THREADS_PER_BLOCK, 0,
            at::cuda::getCurrentCUDAStream()>>>(
            num_kernels, data_col_, data_im_, data_offset_, channels, height,
            width, ksize_h, ksize_w, pad_h, pad_w, stride_h, stride_w,
            dilation_h, dilation_w, channel_per_deformable_group, parallel_imgs,
            2 * ksize_h * ksize_w * deformable_group, deformable_group,
            height_col, width_col, grad_offset_);
      }));
  AT_CUDA_CHECK(cudaGetLastError());
}

void deform_conv_shape_check(Tensor input, Tensor offset, Tensor *gradOutput,
                             Tensor weight, int kH, int kW, int dH, int dW,
                             int padH, int padW, int dilationH, int dilationW,
                             int group, int deformable_group) {
  TORCH_CHECK(
      weight.ndimension() == 4,
      "4D weight tensor (nOutputPlane,nInputPlane,kH,kW) expected, but got: %s",
      weight.ndimension());

  TORCH_CHECK(weight.is_contiguous(), "weight tensor has to be contiguous");

  TORCH_CHECK(kW > 0 && kH > 0,
              "kernel size should be greater than zero, but got kH: %d kW: %d",
              kH, kW);

  TORCH_CHECK((weight.size(2) == kH && weight.size(3) == kW),
              "kernel size should be consistent with weight, ",
              "but got kH: %d kW: %d weight.size(2): %d, weight.size(3): %d",
              kH, kW, weight.size(2), weight.size(3));

  TORCH_CHECK(dW > 0 && dH > 0,
              "stride should be greater than zero, but got dH: %d dW: %d", dH,
              dW);

  TORCH_CHECK(
      dilationW > 0 && dilationH > 0,
      "dilation should be greater than 0, but got dilationH: %d dilationW: %d",
      dilationH, dilationW);

  int ndim = input.ndimension();
  int dimf = 0;
  int dimh = 1;
  int dimw = 2;

  if (ndim == 4) {
    dimf++;
    dimh++;
    dimw++;
  }

  TORCH_CHECK(ndim == 3 || ndim == 4,
              "3D or 4D input tensor expected but got: %s", ndim);

  long nInputPlane = weight.size(1) * group;
  long inputHeight = input.size(dimh);
  long inputWidth = input.size(dimw);
  long nOutputPlane = weight.size(0);
  long outputHeight =
      (inputHeight + 2 * padH - (dilationH * (kH - 1) + 1)) / dH + 1;
  long outputWidth =
      (inputWidth + 2 * padW - (dilationW * (kW - 1) + 1)) / dW + 1;

  TORCH_CHECK(nInputPlane % deformable_group == 0,
              "input channels must divide deformable group size");

  if (outputWidth < 1 || outputHeight < 1)
    AT_ERROR(
        "Given input size: (%ld x %ld x %ld). "
        "Calculated output size: (%ld x %ld x %ld). Output size is too small",
        nInputPlane, inputHeight, inputWidth, nOutputPlane, outputHeight,
        outputWidth);

  TORCH_CHECK(input.size(1) == nInputPlane,
              "invalid number of input planes, expected: %d, but got: %d",
              nInputPlane, input.size(1));

  TORCH_CHECK((inputHeight >= kH && inputWidth >= kW),
              "input image is smaller than kernel");

  TORCH_CHECK(
      (offset.size(2) == outputHeight && offset.size(3) == outputWidth),
      "invalid spatial size of offset, expected height: %d width: %d, but "
      "got height: %d width: %d",
      outputHeight, outputWidth, offset.size(2), offset.size(3));

  TORCH_CHECK((offset.size(1) == deformable_group * 2 * kH * kW),
              "invalid number of channels of offset");

  if (gradOutput != NULL) {
    TORCH_CHECK(
        gradOutput->size(dimf) == nOutputPlane,
        "invalid number of gradOutput planes, expected: %d, but got: %d",
        nOutputPlane, gradOutput->size(dimf));

    TORCH_CHECK(
        (gradOutput->size(dimh) == outputHeight &&
         gradOutput->size(dimw) == outputWidth),
        "invalid size of gradOutput, expected height: %d width: %d , but "
        "got height: %d width: %d",
        outputHeight, outputWidth, gradOutput->size(dimh),
        gradOutput->size(dimw));
  }
}

void DeformConvForwardCUDAKernelLauncher(Tensor input, Tensor weight,
                                         Tensor offset, Tensor output,
                                         Tensor columns, Tensor ones, int kW,
                                         int kH, int dW, int dH, int padW,
                                         int padH, int dilationW, int dilationH,
                                         int group, int deformable_group,
                                         int im2col_step) {
  // todo: resize columns to include im2col: done
  // todo: add im2col_step as input
  // todo: add new output buffer and transpose it to output (or directly
  // transpose output) todo: possibly change data indexing because of
  // parallel_imgs

  deform_conv_shape_check(input, offset, NULL, weight, kH, kW, dH, dW, padH,
                          padW, dilationH, dilationW, group, deformable_group);
  at::DeviceGuard guard(input.device());

  int batch = 1;
  if (input.ndimension() == 3) {
    // Force batch
    batch = 0;
    input.unsqueeze_(0);
    offset.unsqueeze_(0);
  }

  // todo: assert batchsize dividable by im2col_step

  long batchSize = input.size(0);
  long nInputPlane = input.size(1);
  long inputHeight = input.size(2);
  long inputWidth = input.size(3);

  long nOutputPlane = weight.size(0);

  long outputWidth =
      (inputWidth + 2 * padW - (dilationW * (kW - 1) + 1)) / dW + 1;
  long outputHeight =
      (inputHeight + 2 * padH - (dilationH * (kH - 1) + 1)) / dH + 1;

  TORCH_CHECK((offset.size(0) == batchSize), "invalid batch size of offset");

  output = output.view({batchSize / im2col_step, im2col_step, nOutputPlane,
                        outputHeight, outputWidth});
  columns = at::zeros(
      {nInputPlane * kW * kH, im2col_step * outputHeight * outputWidth},
      input.options());

  if (ones.ndimension() != 2 ||
      ones.size(0) * ones.size(1) < outputHeight * outputWidth) {
    ones = at::ones({outputHeight, outputWidth}, input.options());
  }

  input = input.view({batchSize / im2col_step, im2col_step, nInputPlane,
                      inputHeight, inputWidth});
  offset =
      offset.view({batchSize / im2col_step, im2col_step,
                   deformable_group * 2 * kH * kW, outputHeight, outputWidth});

  Tensor output_buffer = at::zeros({batchSize / im2col_step, nOutputPlane,
                                    im2col_step * outputHeight, outputWidth},
                                   output.options());

  output_buffer = output_buffer.view(
      {output_buffer.size(0), group, output_buffer.size(1) / group,
       output_buffer.size(2), output_buffer.size(3)});

  for (int elt = 0; elt < batchSize / im2col_step; elt++) {
    deformable_im2col(input[elt], offset[elt], nInputPlane, inputHeight,
                      inputWidth, kH, kW, padH, padW, dH, dW, dilationH,
                      dilationW, im2col_step, deformable_group, columns);

    columns = columns.view({group, columns.size(0) / group, columns.size(1)});
    weight = weight.view({group, weight.size(0) / group, weight.size(1),
                          weight.size(2), weight.size(3)});

    for (int g = 0; g < group; g++) {
      output_buffer[elt][g] = output_buffer[elt][g]
                                  .flatten(1)
                                  .addmm_(weight[g].flatten(1), columns[g])
                                  .view_as(output_buffer[elt][g]);
    }
    columns =
        columns.view({columns.size(0) * columns.size(1), columns.size(2)});
    weight = weight.view({weight.size(0) * weight.size(1), weight.size(2),
                          weight.size(3), weight.size(4)});
  }

  output_buffer = output_buffer.view(
      {output_buffer.size(0), output_buffer.size(1) * output_buffer.size(2),
       output_buffer.size(3), output_buffer.size(4)});

  output_buffer = output_buffer.view({batchSize / im2col_step, nOutputPlane,
                                      im2col_step, outputHeight, outputWidth});
  output_buffer.transpose_(1, 2);
  output.copy_(output_buffer);
  output = output.view({batchSize, nOutputPlane, outputHeight, outputWidth});

  input = input.view({batchSize, nInputPlane, inputHeight, inputWidth});
  offset = offset.view(
      {batchSize, deformable_group * 2 * kH * kW, outputHeight, outputWidth});

  if (batch == 0) {
    output = output.view({nOutputPlane, outputHeight, outputWidth});
    input = input.view({nInputPlane, inputHeight, inputWidth});
    offset = offset.view({offset.size(1), offset.size(2), offset.size(3)});
  }
}

void DeformConvBackwardInputCUDAKernelLauncher(
    Tensor input, Tensor offset, Tensor gradOutput, Tensor gradInput,
    Tensor gradOffset, Tensor weight, Tensor columns, int kW, int kH, int dW,
    int dH, int padW, int padH, int dilationW, int dilationH, int group,
    int deformable_group, int im2col_step) {
  deform_conv_shape_check(input, offset, &gradOutput, weight, kH, kW, dH, dW,
                          padH, padW, dilationH, dilationW, group,
                          deformable_group);
  at::DeviceGuard guard(input.device());

  int batch = 1;

  if (input.ndimension() == 3) {
    // Force batch
    batch = 0;
    input = input.view({1, input.size(0), input.size(1), input.size(2)});
    offset = offset.view({1, offset.size(0), offset.size(1), offset.size(2)});
    gradOutput = gradOutput.view(
        {1, gradOutput.size(0), gradOutput.size(1), gradOutput.size(2)});
  }

  long batchSize = input.size(0);
  long nInputPlane = input.size(1);
  long inputHeight = input.size(2);
  long inputWidth = input.size(3);

  long nOutputPlane = weight.size(0);

  long outputWidth =
      (inputWidth + 2 * padW - (dilationW * (kW - 1) + 1)) / dW + 1;
  long outputHeight =
      (inputHeight + 2 * padH - (dilationH * (kH - 1) + 1)) / dH + 1;

  TORCH_CHECK((offset.size(0) == batchSize), 3, "invalid batch size of offset");
  gradInput = gradInput.view({batchSize, nInputPlane, inputHeight, inputWidth});
  columns = at::zeros(
      {nInputPlane * kW * kH, im2col_step * outputHeight * outputWidth},
      input.options());

  // change order of grad output
  gradOutput = gradOutput.view({batchSize / im2col_step, im2col_step,
                                nOutputPlane, outputHeight, outputWidth});
  gradOutput.transpose_(1, 2);

  gradInput = gradInput.view({batchSize / im2col_step, im2col_step, nInputPlane,
                              inputHeight, inputWidth});
  input = input.view({batchSize / im2col_step, im2col_step, nInputPlane,
                      inputHeight, inputWidth});
  gradOffset = gradOffset.view({batchSize / im2col_step, im2col_step,
                                deformable_group * 2 * kH * kW, outputHeight,
                                outputWidth});
  offset =
      offset.view({batchSize / im2col_step, im2col_step,
                   deformable_group * 2 * kH * kW, outputHeight, outputWidth});

  for (int elt = 0; elt < batchSize / im2col_step; elt++) {
    // divide into groups
    columns = columns.view({group, columns.size(0) / group, columns.size(1)});
    weight = weight.view({group, weight.size(0) / group, weight.size(1),
                          weight.size(2), weight.size(3)});
    gradOutput = gradOutput.view(
        {gradOutput.size(0), group, gradOutput.size(1) / group,
         gradOutput.size(2), gradOutput.size(3), gradOutput.size(4)});

    for (int g = 0; g < group; g++) {
      columns[g] = columns[g].addmm_(weight[g].flatten(1).transpose(0, 1),
                                     gradOutput[elt][g].flatten(1), 0.0f, 1.0f);
    }

    columns =
        columns.view({columns.size(0) * columns.size(1), columns.size(2)});
    gradOutput = gradOutput.view(
        {gradOutput.size(0), gradOutput.size(1) * gradOutput.size(2),
         gradOutput.size(3), gradOutput.size(4), gradOutput.size(5)});

    deformable_col2im_coord(columns, input[elt], offset[elt], nInputPlane,
                            inputHeight, inputWidth, kH, kW, padH, padW, dH, dW,
                            dilationH, dilationW, im2col_step, deformable_group,
                            gradOffset[elt]);

    deformable_col2im(columns, offset[elt], nInputPlane, inputHeight,
                      inputWidth, kH, kW, padH, padW, dH, dW, dilationH,
                      dilationW, im2col_step, deformable_group, gradInput[elt]);
    weight = weight.view({weight.size(0) * weight.size(1), weight.size(2),
                          weight.size(3), weight.size(4)});
  }

  gradOutput.transpose_(1, 2);
  gradOutput =
      gradOutput.view({batchSize, nOutputPlane, outputHeight, outputWidth});

  gradInput = gradInput.view({batchSize, nInputPlane, inputHeight, inputWidth});
  input = input.view({batchSize, nInputPlane, inputHeight, inputWidth});
  gradOffset = gradOffset.view(
      {batchSize, deformable_group * 2 * kH * kW, outputHeight, outputWidth});
  offset = offset.view(
      {batchSize, deformable_group * 2 * kH * kW, outputHeight, outputWidth});

  if (batch == 0) {
    gradOutput = gradOutput.view({nOutputPlane, outputHeight, outputWidth});
    input = input.view({nInputPlane, inputHeight, inputWidth});
    gradInput = gradInput.view({nInputPlane, inputHeight, inputWidth});
    offset = offset.view({offset.size(1), offset.size(2), offset.size(3)});
    gradOffset =
        gradOffset.view({offset.size(1), offset.size(2), offset.size(3)});
  }
}

void DeformConvBackwardParametersCUDAKernelLauncher(
    Tensor input, Tensor offset, Tensor gradOutput, Tensor gradWeight,
    Tensor columns, Tensor ones, int kW, int kH, int dW, int dH, int padW,
    int padH, int dilationW, int dilationH, int group, int deformable_group,
    float scale, int im2col_step) {
  // todo: transpose and reshape outGrad
  // todo: reshape columns
  // todo: add im2col_step as input

  deform_conv_shape_check(input, offset, &gradOutput, gradWeight, kH, kW, dH,
                          dW, padH, padW, dilationH, dilationW, group,
                          deformable_group);
  at::DeviceGuard guard(input.device());

  int batch = 1;

  if (input.ndimension() == 3) {
    // Force batch
    batch = 0;
    input = input.view(
        at::IntList({1, input.size(0), input.size(1), input.size(2)}));
    gradOutput = gradOutput.view(
        {1, gradOutput.size(0), gradOutput.size(1), gradOutput.size(2)});
  }

  long batchSize = input.size(0);
  long nInputPlane = input.size(1);
  long inputHeight = input.size(2);
  long inputWidth = input.size(3);

  long nOutputPlane = gradWeight.size(0);

  long outputWidth =
      (inputWidth + 2 * padW - (dilationW * (kW - 1) + 1)) / dW + 1;
  long outputHeight =
      (inputHeight + 2 * padH - (dilationH * (kH - 1) + 1)) / dH + 1;

  TORCH_CHECK((offset.size(0) == batchSize), "invalid batch size of offset");

  columns = at::zeros(
      {nInputPlane * kW * kH, im2col_step * outputHeight * outputWidth},
      input.options());

  gradOutput = gradOutput.view({batchSize / im2col_step, im2col_step,
                                nOutputPlane, outputHeight, outputWidth});
  gradOutput.transpose_(1, 2);

  Tensor gradOutputBuffer = at::zeros_like(gradOutput);
  gradOutputBuffer =
      gradOutputBuffer.view({batchSize / im2col_step, nOutputPlane, im2col_step,
                             outputHeight, outputWidth});
  gradOutputBuffer = gradOutputBuffer.contiguous();
  gradOutputBuffer.copy_(gradOutput);
  gradOutputBuffer =
      gradOutputBuffer.view({batchSize / im2col_step, nOutputPlane,
                             im2col_step * outputHeight, outputWidth});

  gradOutput.transpose_(1, 2);
  gradOutput =
      gradOutput.view({batchSize, nOutputPlane, outputHeight, outputWidth});

  input = input.view({batchSize / im2col_step, im2col_step, nInputPlane,
                      inputHeight, inputWidth});
  offset =
      offset.view({batchSize / im2col_step, im2col_step,
                   deformable_group * 2 * kH * kW, outputHeight, outputWidth});

  for (int elt = 0; elt < batchSize / im2col_step; elt++) {
    deformable_im2col(input[elt], offset[elt], nInputPlane, inputHeight,
                      inputWidth, kH, kW, padH, padW, dH, dW, dilationH,
                      dilationW, im2col_step, deformable_group, columns);

    // divide into group
    gradOutputBuffer = gradOutputBuffer.view(
        {gradOutputBuffer.size(0), group, gradOutputBuffer.size(1) / group,
         gradOutputBuffer.size(2), gradOutputBuffer.size(3)});
    columns = columns.view({group, columns.size(0) / group, columns.size(1)});
    gradWeight =
        gradWeight.view({group, gradWeight.size(0) / group, gradWeight.size(1),
                         gradWeight.size(2), gradWeight.size(3)});

    for (int g = 0; g < group; g++) {
      gradWeight[g] = gradWeight[g]
                          .flatten(1)
                          .addmm_(gradOutputBuffer[elt][g].flatten(1),
                                  columns[g].transpose(1, 0), 1.0, scale)
                          .view_as(gradWeight[g]);
    }
    gradOutputBuffer = gradOutputBuffer.view(
        {gradOutputBuffer.size(0),
         gradOutputBuffer.size(1) * gradOutputBuffer.size(2),
         gradOutputBuffer.size(3), gradOutputBuffer.size(4)});
    columns =
        columns.view({columns.size(0) * columns.size(1), columns.size(2)});
    gradWeight = gradWeight.view({gradWeight.size(0) * gradWeight.size(1),
                                  gradWeight.size(2), gradWeight.size(3),
                                  gradWeight.size(4)});
  }

  input = input.view({batchSize, nInputPlane, inputHeight, inputWidth});
  offset = offset.view(
      {batchSize, deformable_group * 2 * kH * kW, outputHeight, outputWidth});

  if (batch == 0) {
    gradOutput = gradOutput.view({nOutputPlane, outputHeight, outputWidth});
    input = input.view({nInputPlane, inputHeight, inputWidth});
  }
}
