/*
 * Copyright (c) 2024 by FlashInfer team.
 *
 * 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.
 */
#include <flashinfer/pos_enc.cuh>

#include "pytorch_extension_utils.h"

using namespace flashinfer;

void apply_rope_pos_ids_cos_sin_cache(
    at::Tensor q,
    at::Tensor k,
    at::Tensor q_rope,
    at::Tensor k_rope,
    at::Tensor cos_sin_cache,
    at::Tensor pos_ids,
    bool interleave,
    int64_t cuda_stream) {
  CHECK_LAST_DIM_CONTIGUOUS(q);
  CHECK_LAST_DIM_CONTIGUOUS(k);
  CHECK_INPUT(cos_sin_cache);
  CHECK_INPUT(pos_ids);
  auto device = q.device();
  CHECK_EQ(k.device(), device);
  CHECK_EQ(cos_sin_cache.device(), device);
  CHECK_EQ(pos_ids.device(), device);
  CHECK_DIM(3, q);  // q: (nnz, H_Q, D)
  CHECK_DIM(3, k);  // k: (nnz, H_K, D)
  // cos_sin_cache: (max_seq_len, R)
  // First half of R is cos, second half is sin
  CHECK_DIM(2, cos_sin_cache);
  CHECK_EQ(q.size(0), k.size(0));
  CHECK_EQ(q.size(2), k.size(2));
  unsigned int rotary_dim = cos_sin_cache.size(1);
  unsigned int num_qo_heads = q.size(1);
  unsigned int num_kv_heads = k.size(1);
  unsigned int head_dim = q.size(2);
  unsigned int nnz = q.size(0);
  size_t q_stride_n = q.stride(0);
  size_t q_stride_h = q.stride(1);
  size_t k_stride_n = k.stride(0);
  size_t k_stride_h = k.stride(1);
  size_t q_rope_stride_n = q_rope.stride(0);
  size_t q_rope_stride_h = q_rope.stride(1);
  size_t k_rope_stride_n = k_rope.stride(0);
  size_t k_rope_stride_h = k_rope.stride(1);

  cudaStream_t stream = reinterpret_cast<cudaStream_t>(cuda_stream);
  DISPATCH_PYTORCH_DTYPE_TO_CTYPE_FP16(q.scalar_type(), c_type, [&] {
    cudaError_t status = BatchQKApplyRotaryPosIdsCosSinCache(
        static_cast<c_type*>(q.data_ptr()),
        static_cast<c_type*>(k.data_ptr()),
        static_cast<c_type*>(q_rope.data_ptr()),
        static_cast<c_type*>(k_rope.data_ptr()),
        static_cast<float*>(cos_sin_cache.data_ptr()),
        static_cast<int32_t*>(pos_ids.data_ptr()),
        nnz,
        num_qo_heads,
        num_kv_heads,
        rotary_dim,
        head_dim,
        q_stride_n,
        q_stride_h,
        k_stride_n,
        k_stride_h,
        q_rope_stride_n,
        q_rope_stride_h,
        k_rope_stride_n,
        k_rope_stride_h,
        interleave,
        stream);
    TORCH_CHECK(
        status == cudaSuccess,
        "BatchQKApplyRotaryPosIdsCosSinCache failed with error code " + std::string(cudaGetErrorString(status)));
    return true;
  });
}
