/* Copyright 2019 The TensorFlow 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.
==============================================================================*/

#ifndef TENSORFLOW_LITE_DELEGATES_GPU_COMMON_TASKS_DEPTHWISE_CONV_H_
#define TENSORFLOW_LITE_DELEGATES_GPU_COMMON_TASKS_DEPTHWISE_CONV_H_

#include <vector>

#include "tensorflow/lite/delegates/gpu/common/data_type.h"
#include "tensorflow/lite/delegates/gpu/common/operations.h"
#include "tensorflow/lite/delegates/gpu/common/shape.h"
#include "tensorflow/lite/delegates/gpu/common/status.h"
#include "tensorflow/lite/delegates/gpu/common/task/buffer_desc.h"
#include "tensorflow/lite/delegates/gpu/common/task/gpu_operation.h"
#include "tensorflow/lite/delegates/gpu/common/task/tensor_desc.h"
#include "tensorflow/lite/delegates/gpu/common/task/tensor_linear_desc.h"
#include "tensorflow/lite/delegates/gpu/common/task/texture2d_desc.h"
#include "tensorflow/lite/delegates/gpu/common/tensor.h"
#include "tensorflow/lite/delegates/gpu/common/types.h"

namespace tflite {
namespace gpu {

template <DataType S, typename T>
void RearrangeWeightsForDWConv2D(const tflite::gpu::Tensor<OHWI, S>& weights,
                                 absl::Span<T> dst) {
  const int dst_channels = weights.shape.i * weights.shape.o;
  const int dst_depth = DivideRoundUp(dst_channels, 4);
  const int kernel_x = weights.shape.w;
  const int kernel_y = weights.shape.h;

  int counter = 0;
  for (int d = 0; d < dst_depth; ++d) {
    for (int y = 0; y < kernel_y; ++y) {
      for (int x = 0; x < kernel_x; ++x) {
        T filter_val;
        for (int i = 0; i < 4; ++i) {
          const int d_ch = d * 4 + i;
          if (d_ch < dst_channels) {
            const int f_index = weights.shape.LinearIndex(
                {d_ch % weights.shape.o, y, x, d_ch / weights.shape.o});
            filter_val[i] = weights.data[f_index];
          } else {
            filter_val[i] = 0.0f;
          }
        }
        dst[counter++] = filter_val;
      }
    }
  }
}

template <DataType T>
void UploadWeightsForDWConv2D(const tflite::gpu::Tensor<OHWI, T>& weights,
                              bool weights_are_buffer,
                              CalculationsPrecision precision,
                              GPUOperation* op) {
  const int dst_channels = weights.shape.i * weights.shape.o;
  const int dst_slices = DivideRoundUp(dst_channels, 4);
  const int kernel_x = weights.shape.w;
  const int kernel_y = weights.shape.h;

  const int elements_count = kernel_x * kernel_y * dst_slices;

  const bool fp32_weights = precision == CalculationsPrecision::F32;
  const int float4_size = fp32_weights ? 16 : 8;

  std::vector<uint8_t> data(float4_size * elements_count);

  if (fp32_weights) {
    float4* ptr = reinterpret_cast<float4*>(data.data());
    RearrangeWeightsForDWConv2D(weights, absl::MakeSpan(ptr, elements_count));
  } else {
    half4* ptr = reinterpret_cast<half4*>(data.data());
    RearrangeWeightsForDWConv2D(weights, absl::MakeSpan(ptr, elements_count));
  }

  if (weights_are_buffer) {
    BufferDescriptor desc;
    desc.element_type = fp32_weights ? DataType::FLOAT32 : DataType::FLOAT16;
    desc.element_size = 4;
    desc.size = float4_size * elements_count;
    desc.data = std::move(data);
    op->args_.AddObject("weights", absl::make_unique<BufferDescriptor>(desc));
  } else {
    Texture2DDescriptor desc;
    desc.element_type = fp32_weights ? DataType::FLOAT32 : DataType::FLOAT16;
    desc.size = int2(kernel_x * kernel_y, dst_slices);
    desc.data = std::move(data);
    op->args_.AddObject("weights",
                        absl::make_unique<Texture2DDescriptor>(desc));
  }
}

template <DataType S, typename T>
void RearrangeWeightsForDWConv3D(const tflite::gpu::Tensor<OHWDI, S>& weights,
                                 absl::Span<T> dst) {
  const int dst_channels = weights.shape.i * weights.shape.o;
  const int dst_slices = DivideRoundUp(dst_channels, 4);
  const int kernel_x = weights.shape.w;
  const int kernel_y = weights.shape.h;
  const int kernel_z = weights.shape.d;

  int counter = 0;
  for (int d = 0; d < dst_slices; ++d) {
    for (int z = 0; z < kernel_z; ++z) {
      for (int y = 0; y < kernel_y; ++y) {
        for (int x = 0; x < kernel_x; ++x) {
          T filter_val;
          for (int i = 0; i < 4; ++i) {
            const int d_ch = d * 4 + i;
            if (d_ch < dst_channels) {
              const int f_index = weights.shape.LinearIndex(
                  {d_ch % weights.shape.o, y, x, z, d_ch / weights.shape.o});
              filter_val[i] = weights.data[f_index];
            } else {
              filter_val[i] = 0.0f;
            }
          }
          dst[counter++] = filter_val;
        }
      }
    }
  }
}

template <DataType T>
void UploadWeightsForDWConv3D(const tflite::gpu::Tensor<OHWDI, T>& weights,
                              bool weights_are_buffer,
                              CalculationsPrecision precision,
                              GPUOperation* op) {
  const int dst_channels = weights.shape.i * weights.shape.o;
  const int dst_slices = DivideRoundUp(dst_channels, 4);
  const int kernel_x = weights.shape.w;
  const int kernel_y = weights.shape.h;
  const int kernel_z = weights.shape.d;

  const int elements_count = kernel_x * kernel_y * kernel_z * dst_slices;

  const bool fp32_weights = precision == CalculationsPrecision::F32;
  const int float4_size = fp32_weights ? 16 : 8;

  std::vector<uint8_t> data(float4_size * elements_count);

  if (fp32_weights) {
    float4* ptr = reinterpret_cast<float4*>(data.data());
    RearrangeWeightsForDWConv3D(weights, absl::MakeSpan(ptr, elements_count));
  } else {
    half4* ptr = reinterpret_cast<half4*>(data.data());
    RearrangeWeightsForDWConv3D(weights, absl::MakeSpan(ptr, elements_count));
  }

  if (weights_are_buffer) {
    BufferDescriptor desc;
    desc.element_type = fp32_weights ? DataType::FLOAT32 : DataType::FLOAT16;
    desc.element_size = 4;
    desc.size = float4_size * elements_count;
    desc.data = std::move(data);
    op->args_.AddObject("weights",
                        absl::make_unique<BufferDescriptor>(std::move(desc)));
  } else {
    Texture2DDescriptor desc;
    desc.element_type = fp32_weights ? DataType::FLOAT32 : DataType::FLOAT16;
    desc.size = int2(kernel_x * kernel_y * kernel_z, dst_slices);
    desc.data = std::move(data);
    op->args_.AddObject(
        "weights", absl::make_unique<Texture2DDescriptor>(std::move(desc)));
  }
}

GPUOperation CreateDepthwiseConvolution2D(
    const GpuInfo& gpu_info, const OperationDef& definition,
    const DepthwiseConvolution2DAttributes& attr);

GPUOperation CreateDepthwiseConvolution2DDynamicWeights(
    const GpuInfo& gpu_info, const OperationDef& definition,
    const DepthwiseConvolution2DAttributes& attr);

GPUOperation CreateDepthwiseConvolution3D(
    const GpuInfo& gpu_info, const OperationDef& definition,
    const DepthwiseConvolution3DAttributes& attr);

}  // namespace gpu
}  // namespace tflite

#endif  // TENSORFLOW_LITE_DELEGATES_GPU_COMMON_TASKS_DEPTHWISE_CONV_H_
