/*
 * Copyright (c) 2020-2023, NVIDIA CORPORATION.  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.
 */

#pragma once

#include "src/fastertransformer/cutlass_extensions/include/cutlass_extensions/ft_gemm_configs.h"
#include "src/fastertransformer/utils/activation_types.h"
#include "src/fastertransformer/utils/allocator.h"
#include <cuda_runtime_api.h>

namespace fastertransformer {

/*
  This runner only supports:
  T in {half, __nv_bfloat} WeightType in {int8_t, cutlass::uint4b_t}

  Activations, biases, scales and outputs are all assumed to be row-major.

  However, it is assumed that B is in a special format governed by cutlass_extensions/gemm/kernel/mixed_gemm_B_layout.
  In this case, B must be preprocessed using the cutlass weight only quant preprocessors. The weight preprocessor
  will instantiate the layout and preprocess based on the instantiation, so layout changes should only require
  modifications to mix_gemm_B_layout.h.
*/

template<typename T, typename WeightType>
class CutlassFpAIntBGemmRunner {
public:
    CutlassFpAIntBGemmRunner();
    ~CutlassFpAIntBGemmRunner();

    void gemm(const T*          A,
              const WeightType* B,
              const T*          weight_scales,
              T*                C,
              int               m,
              int               n,
              int               k,
              char*             workspace_ptr,
              const size_t      workspace_bytes,
              cudaStream_t      stream);

    void gemm_bias_act(const T*          A,
                       const WeightType* B,
                       const T*          weight_scales,
                       const T*          biases,
                       T*                C,
                       int               m,
                       int               n,
                       int               k,
                       ActivationType    activation_type,
                       char*             workspace_ptr,
                       const size_t      workspace_bytes,
                       cudaStream_t      stream);

    // Returns desired workspace size in bytes.
    int getWorkspaceSize(const int m, const int n, const int k);

private:
    template<typename EpilogueTag>
    void dispatch_to_arch(const T*          A,
                          const WeightType* B,
                          const T*          weight_scales,
                          const T*          biases,
                          T*                C,
                          int               m,
                          int               n,
                          int               k,
                          CutlassGemmConfig gemm_config,
                          char*             workspace_ptr,
                          const size_t      workspace_bytes,
                          cudaStream_t      stream,
                          int*              occupancy = nullptr);

    template<typename EpilogueTag>
    void run_gemm(const T*          A,
                  const WeightType* B,
                  const T*          weight_scales,
                  const T*          biases,
                  T*                C,
                  int               m,
                  int               n,
                  int               k,
                  char*             workspace_ptr,
                  const size_t      workspace_bytes,
                  cudaStream_t      stream);

private:
    static constexpr int split_k_limit = 7;

    int sm_;
    int multi_processor_count_;
};

// This allocation is present to help with compiling with other structures in FT. It will throw an error
// in all functions because this runner assumes the weight type and the activation type are different.
// We allow empty classes to be created, but any calls to gemm or gemm_bias_act will throw an error.
template<typename WeightType>
class CutlassFpAIntBGemmRunner<float, WeightType> {
public:
    CutlassFpAIntBGemmRunner()  = default;
    ~CutlassFpAIntBGemmRunner() = default;

    void gemm(const float*      A,
              const WeightType* B,
              const float*      weight_scales,
              float*            C,
              int               m,
              int               n,
              int               k,
              char*             workspace_ptr,
              const size_t      workspace_bytes,
              cudaStream_t      stream);

    void gemm_bias_act(const float*      A,
                       const WeightType* B,
                       const float*      weight_scales,
                       const float*      biases,
                       float*            C,
                       int               m,
                       int               n,
                       int               k,
                       ActivationType    activation_type,
                       char*             workspace_ptr,
                       const size_t      workspace_bytes,
                       cudaStream_t      stream);

    int getWorkspaceSize(const int m, const int n, const int k);
};

}  // namespace fastertransformer