/*************************************************************************
 * Copyright (c) 2022-2024, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 *
 * See LICENSE for license information.
 ************************************************************************/

#include "../common.h"
#include "transformer_engine/fused_attn.h"
#include "utils.h"

namespace transformer_engine {
namespace fused_attn {

using namespace transformer_engine;

// get matrix strides based on matrix type
void generateMatrixStrides(int64_t b, int64_t h, int64_t s_q, int64_t s_kv, int64_t d,
                           int64_t *strideA, NVTE_QKV_Layout layout, NVTE_QKV_Matrix matrix) {
  constexpr int batch_dim_idx = 0;
  constexpr int head_dim_idx = 1;
  constexpr int seqlen_dim_idx = 2;
  constexpr int hidden_dim_idx = 3;

  constexpr int seqlen_transpose_dim_idx = 3;
  constexpr int hidden_transpose_dim_idx = 2;

  constexpr int seqlen_q_dim_idx = 2;
  constexpr int seqlen_kv_dim_idx = 3;

  switch (layout) {
    case NVTE_QKV_Layout::NVTE_SB3HD:
      if ((matrix == NVTE_QKV_Matrix::NVTE_Q_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_K_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix)) {
        strideA[batch_dim_idx] = 3 * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = b * 3 * h * d;
        strideA[hidden_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix_Transpose) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix_Transpose)) {
        strideA[batch_dim_idx] = 3 * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_transpose_dim_idx] = b * 3 * h * d;
        strideA[hidden_transpose_dim_idx] = 1;
      } else if (matrix == NVTE_QKV_Matrix::NVTE_O_Matrix) {
        strideA[batch_dim_idx] = h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = b * h * d;
        strideA[hidden_dim_idx] = 1;
      }
      break;
    case NVTE_QKV_Layout::NVTE_SBH3D:
      if ((matrix == NVTE_QKV_Matrix::NVTE_Q_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_K_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix)) {
        strideA[batch_dim_idx] = 3 * h * d;
        strideA[head_dim_idx] = 3 * d;
        strideA[seqlen_dim_idx] = b * 3 * h * d;
        strideA[hidden_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix_Transpose) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix_Transpose)) {
        strideA[batch_dim_idx] = 3 * h * d;
        strideA[head_dim_idx] = 3 * d;
        strideA[seqlen_transpose_dim_idx] = b * 3 * h * d;
        strideA[hidden_transpose_dim_idx] = 1;
      } else if (matrix == NVTE_QKV_Matrix::NVTE_O_Matrix) {
        strideA[batch_dim_idx] = h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = b * h * d;
        strideA[hidden_dim_idx] = 1;
      }
      break;
    case NVTE_QKV_Layout::NVTE_SBHD_SB2HD:
      if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix)) {
        strideA[batch_dim_idx] = 2 * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = b * 2 * h * d;
        strideA[hidden_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix_Transpose) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix_Transpose)) {
        strideA[batch_dim_idx] = 2 * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_transpose_dim_idx] = b * 2 * h * d;
        strideA[hidden_transpose_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_Q_Matrix) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_O_Matrix)) {
        strideA[batch_dim_idx] = h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = b * h * d;
        strideA[hidden_dim_idx] = 1;
      }
      break;
    case NVTE_QKV_Layout::NVTE_SBHD_SBH2D:
      if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix)) {
        strideA[batch_dim_idx] = 2 * h * d;
        strideA[head_dim_idx] = 2 * d;
        strideA[seqlen_dim_idx] = b * 2 * h * d;
        strideA[hidden_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix_Transpose) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix_Transpose)) {
        strideA[batch_dim_idx] = 2 * h * d;
        strideA[head_dim_idx] = 2 * d;
        strideA[seqlen_transpose_dim_idx] = b * 2 * h * d;
        strideA[hidden_transpose_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_Q_Matrix) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_O_Matrix)) {
        strideA[batch_dim_idx] = h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = b * h * d;
        strideA[hidden_dim_idx] = 1;
      }
      break;
    case NVTE_QKV_Layout::NVTE_SBHD_SBHD_SBHD:
      if ((matrix == NVTE_QKV_Matrix::NVTE_Q_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_K_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_O_Matrix)) {
        strideA[batch_dim_idx] = h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = b * h * d;
        strideA[hidden_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix_Transpose) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix_Transpose)) {
        strideA[batch_dim_idx] = h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_transpose_dim_idx] = b * h * d;
        strideA[hidden_transpose_dim_idx] = 1;
      }
      break;
    case NVTE_QKV_Layout::NVTE_BS3HD:
    case NVTE_QKV_Layout::NVTE_T3HD:
      if ((matrix == NVTE_QKV_Matrix::NVTE_Q_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_K_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix)) {
        strideA[batch_dim_idx] = s_q * 3 * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = 3 * h * d;
        strideA[hidden_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix_Transpose) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix_Transpose)) {
        strideA[batch_dim_idx] = s_q * 3 * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_transpose_dim_idx] = 3 * h * d;
        strideA[hidden_transpose_dim_idx] = 1;
      } else if (matrix == NVTE_QKV_Matrix::NVTE_O_Matrix) {
        strideA[batch_dim_idx] = s_q * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = h * d;
        strideA[hidden_dim_idx] = 1;
      }
      break;
    case NVTE_QKV_Layout::NVTE_BSH3D:
    case NVTE_QKV_Layout::NVTE_TH3D:
      if ((matrix == NVTE_QKV_Matrix::NVTE_Q_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_K_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix)) {
        strideA[batch_dim_idx] = s_q * 3 * h * d;
        strideA[head_dim_idx] = 3 * d;
        strideA[seqlen_dim_idx] = 3 * h * d;
        strideA[hidden_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix_Transpose) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix_Transpose)) {
        strideA[batch_dim_idx] = s_q * 3 * h * d;
        strideA[head_dim_idx] = 3 * d;
        strideA[seqlen_transpose_dim_idx] = 3 * h * d;
        strideA[hidden_transpose_dim_idx] = 1;
      } else if (matrix == NVTE_QKV_Matrix::NVTE_O_Matrix) {
        strideA[batch_dim_idx] = s_q * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = h * d;
        strideA[hidden_dim_idx] = 1;
      }
      break;
    case NVTE_QKV_Layout::NVTE_BSHD_BS2HD:
    case NVTE_QKV_Layout::NVTE_THD_T2HD:
      if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix)) {
        strideA[batch_dim_idx] = s_kv * 2 * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = 2 * h * d;
        strideA[hidden_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix_Transpose) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix_Transpose)) {
        strideA[batch_dim_idx] = s_kv * 2 * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_transpose_dim_idx] = 2 * h * d;
        strideA[hidden_transpose_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_Q_Matrix) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_O_Matrix)) {
        strideA[batch_dim_idx] = s_q * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = h * d;
        strideA[hidden_dim_idx] = 1;
      }
      break;
    case NVTE_QKV_Layout::NVTE_BSHD_BSH2D:
    case NVTE_QKV_Layout::NVTE_THD_TH2D:
      if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix)) {
        strideA[batch_dim_idx] = s_kv * 2 * h * d;
        strideA[head_dim_idx] = 2 * d;
        strideA[seqlen_dim_idx] = 2 * h * d;
        strideA[hidden_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix_Transpose) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix_Transpose)) {
        strideA[batch_dim_idx] = s_kv * 2 * h * d;
        strideA[head_dim_idx] = 2 * d;
        strideA[seqlen_transpose_dim_idx] = 2 * h * d;
        strideA[hidden_transpose_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_Q_Matrix) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_O_Matrix)) {
        strideA[batch_dim_idx] = s_q * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = h * d;
        strideA[hidden_dim_idx] = 1;
      }
      break;
    case NVTE_QKV_Layout::NVTE_BSHD_BSHD_BSHD:
    case NVTE_QKV_Layout::NVTE_THD_THD_THD:
      if ((matrix == NVTE_QKV_Matrix::NVTE_Q_Matrix) ||
          (matrix == NVTE_QKV_Matrix::NVTE_O_Matrix)) {
        strideA[batch_dim_idx] = s_q * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = h * d;
        strideA[hidden_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix)) {
        strideA[batch_dim_idx] = s_kv * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_dim_idx] = h * d;
        strideA[hidden_dim_idx] = 1;
      } else if ((matrix == NVTE_QKV_Matrix::NVTE_K_Matrix_Transpose) ||
                 (matrix == NVTE_QKV_Matrix::NVTE_V_Matrix_Transpose)) {
        strideA[batch_dim_idx] = s_kv * h * d;
        strideA[head_dim_idx] = d;
        strideA[seqlen_transpose_dim_idx] = h * d;
        strideA[hidden_transpose_dim_idx] = 1;
      }
      break;
  }

  if (matrix == NVTE_QKV_Matrix::NVTE_S_Matrix) {
    strideA[seqlen_kv_dim_idx] = 1;
    strideA[seqlen_q_dim_idx] = s_kv;
    strideA[head_dim_idx] = s_q * s_kv;
    strideA[batch_dim_idx] = h * s_q * s_kv;
  }
}

bool allowAllConfig(cudnnBackendDescriptor_t engine_config) {
  (void)engine_config;
  return false;
}

cudnn_frontend::Tensor tensor_create(cudnnDataType_t type, int64_t id, int64_t const *dim,
                                     int64_t const *stride, bool is_virtual, bool is_value) {
  int nbDims = 4;
  auto tensor_created =
      cudnn_frontend::TensorBuilder()
          .setDim(nbDims, dim)
          .setStride(nbDims, stride)
          .setId(id)
          .setAlignment(16)  // 16B alignment is needed to run a tensor core engine
          .setDataType(type)
          .setVirtual(is_virtual)
          .setByValue(is_value)
          .build();
  return tensor_created;
}

cudnn_frontend::Tensor tensor_create_with_offset(
    cudnnDataType_t type, int64_t id, int64_t const *dim, int64_t const *stride, bool is_virtual,
    bool is_value, std::shared_ptr<cudnn_frontend::Tensor> raggedOffset) {
  int nbDims = 4;
  auto tensor_created =
      cudnn_frontend::TensorBuilder()
          .setDim(nbDims, dim)
          .setStride(nbDims, stride)
          .setId(id)
          .setAlignment(16)  // 16B alignment is needed to run a tensor core engine
          .setDataType(type)
          .setVirtual(is_virtual)
          .setByValue(is_value)
          .setRaggedOffset(raggedOffset)
          .build();
  return tensor_created;
}

cudnn_frontend::PointWiseDesc pw_desc_create(cudnnDataType_t type, cudnnPointwiseMode_t mode) {
  auto pw_desc_created =
      cudnn_frontend::PointWiseDescBuilder().setMode(mode).setComputeType(type).build();
  return pw_desc_created;
}

cudnn_frontend::Operation unary_pw_op_create(cudnn_frontend::Tensor const &xDesc,
                                             cudnn_frontend::Tensor const &yDesc,
                                             cudnn_frontend::PointWiseDesc const &pwDesc) {
  auto pw_op_created =
      cudnn_frontend::OperationBuilder(CUDNN_BACKEND_OPERATION_POINTWISE_DESCRIPTOR)
          .setxDesc(xDesc)
          .setyDesc(yDesc)
          .setpwDesc(pwDesc)
          .build();
  return pw_op_created;
}

cudnn_frontend::Operation binary_pw_op_create(cudnn_frontend::Tensor const &xDesc,
                                              cudnn_frontend::Tensor const &bDesc,
                                              cudnn_frontend::Tensor const &yDesc,
                                              cudnn_frontend::PointWiseDesc const &pwDesc) {
  auto pw_op_created =
      cudnn_frontend::OperationBuilder(CUDNN_BACKEND_OPERATION_POINTWISE_DESCRIPTOR)
          .setxDesc(xDesc)
          .setbDesc(bDesc)
          .setyDesc(yDesc)
          .setpwDesc(pwDesc)
          .build();
  return pw_op_created;
}

cudnn_frontend::Operation ternary_pw_op_create(cudnn_frontend::Tensor const &xDesc,
                                               cudnn_frontend::Tensor const &bDesc,
                                               cudnn_frontend::Tensor const &tDesc,
                                               cudnn_frontend::Tensor const &yDesc,
                                               cudnn_frontend::PointWiseDesc const &pwDesc) {
  auto pw_op_created =
      cudnn_frontend::OperationBuilder(CUDNN_BACKEND_OPERATION_POINTWISE_DESCRIPTOR)
          .setxDesc(xDesc)
          .setbDesc(bDesc)
          .settDesc(tDesc)
          .setyDesc(yDesc)
          .setpwDesc(pwDesc)
          .build();
  return pw_op_created;
}

// convert cu_seqlens_q to qkv/o_ragged_offset and actual_seqlens_q
__global__ void cu_seqlens_to_offsets(size_t b, size_t h, size_t d, int32_t *cu_seqlens_q,
                                      int32_t *actual_seqlens_q, int32_t *qkv_ragged_offset,
                                      int32_t *o_ragged_offset) {
  size_t tid = blockIdx.x * blockDim.x + threadIdx.x;
  if (tid < b) {
    actual_seqlens_q[tid] = cu_seqlens_q[tid + 1] - cu_seqlens_q[tid];
  }
  if (tid < b + 1) {
    qkv_ragged_offset[tid] = cu_seqlens_q[tid] * 3 * h * d;
    o_ragged_offset[tid] = cu_seqlens_q[tid] * h * d;
  }
}

// convert cu_seqlens to actual_seqlens
__global__ void cu_seqlens_to_actual_seqlens(size_t b, int32_t const *const q_cu_seqlens,
                                             int32_t const *const kv_cu_seqlens, int32_t *q_seqlens,
                                             int32_t *kv_seqlens) {
  size_t tid = blockIdx.x * blockDim.x + threadIdx.x;
  if (tid < b) {
    q_seqlens[tid] = q_cu_seqlens[tid + 1] - q_cu_seqlens[tid];
    kv_seqlens[tid] = kv_cu_seqlens[tid + 1] - kv_cu_seqlens[tid];
  }
}
}  // namespace fused_attn

// get cuDNN data type
cudnnDataType_t get_cudnn_dtype(const transformer_engine::DType t) {
  using namespace transformer_engine;
  switch (t) {
    case DType::kInt32:
      return CUDNN_DATA_INT32;
    case DType::kInt64:
      return CUDNN_DATA_INT64;
    case DType::kFloat16:
      return CUDNN_DATA_HALF;
    case DType::kFloat32:
      return CUDNN_DATA_FLOAT;
    case DType::kBFloat16:
      return CUDNN_DATA_BFLOAT16;
    case DType::kFloat8E4M3:
      return CUDNN_DATA_FP8_E4M3;
    case DType::kFloat8E5M2:
      return CUDNN_DATA_FP8_E5M2;
    default:
      NVTE_ERROR("Invalid cuDNN data type. \n");
  }
}

// get cuDNN data type
cudnn_frontend::DataType_t get_cudnn_fe_dtype(const transformer_engine::DType t) {
  using namespace transformer_engine;
  switch (t) {
    case DType::kInt32:
      return cudnn_frontend::DataType_t::INT32;
    case DType::kInt64:
      return cudnn_frontend::DataType_t::INT64;
    case DType::kFloat16:
      return cudnn_frontend::DataType_t::HALF;
    case DType::kFloat32:
      return cudnn_frontend::DataType_t::FLOAT;
    case DType::kBFloat16:
      return cudnn_frontend::DataType_t::BFLOAT16;
    case DType::kFloat8E4M3:
      return cudnn_frontend::DataType_t::FP8_E4M3;
    case DType::kFloat8E5M2:
      return cudnn_frontend::DataType_t::FP8_E5M2;
    default:
      NVTE_ERROR("Invalid cuDNN data type. \n");
  }
}
}  // namespace transformer_engine
