// SPDX-License-Identifier: Apache-2.0
//
// Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
// Copyright 2008-2016 National ICT Australia (NICTA)
//
// 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.
// ------------------------------------------------------------------------

#if defined(ARMA_USE_BLAS)

//! \namespace blas namespace for BLAS functions
namespace blas {

template <typename eT>
inline void gemv(const char* transA, const blas_int* m, const blas_int* n,
                 const eT* alpha, const eT* A, const blas_int* ldA, const eT* x,
                 const blas_int* incx, const eT* beta, eT* y, const blas_int* incy) {
  arma_type_check((is_supported_blas_type<eT>::value == false));

#if defined(ARMA_USE_FORTRAN_HIDDEN_ARGS)
  {
    if (is_float<eT>::value) {
      typedef float T;
      arma_fortran(arma_sgemv)(transA, m, n, (const T*)alpha, (const T*)A, ldA,
                               (const T*)x, incx, (const T*)beta, (T*)y, incy, 1);
    } else if (is_double<eT>::value) {
      typedef double T;
      arma_fortran(arma_dgemv)(transA, m, n, (const T*)alpha, (const T*)A, ldA,
                               (const T*)x, incx, (const T*)beta, (T*)y, incy, 1);
    } else if (is_cx_float<eT>::value) {
      typedef blas_cxf T;
      arma_fortran(arma_cgemv)(transA, m, n, (const T*)alpha, (const T*)A, ldA,
                               (const T*)x, incx, (const T*)beta, (T*)y, incy, 1);
    } else if (is_cx_double<eT>::value) {
      typedef blas_cxd T;
      arma_fortran(arma_zgemv)(transA, m, n, (const T*)alpha, (const T*)A, ldA,
                               (const T*)x, incx, (const T*)beta, (T*)y, incy, 1);
    }
  }
#else
  {
    if (is_float<eT>::value) {
      typedef float T;
      arma_fortran(arma_sgemv)(transA, m, n, (const T*)alpha, (const T*)A, ldA,
                               (const T*)x, incx, (const T*)beta, (T*)y, incy);
    } else if (is_double<eT>::value) {
      typedef double T;
      arma_fortran(arma_dgemv)(transA, m, n, (const T*)alpha, (const T*)A, ldA,
                               (const T*)x, incx, (const T*)beta, (T*)y, incy);
    } else if (is_cx_float<eT>::value) {
      typedef blas_cxf T;
      arma_fortran(arma_cgemv)(transA, m, n, (const T*)alpha, (const T*)A, ldA,
                               (const T*)x, incx, (const T*)beta, (T*)y, incy);
    } else if (is_cx_double<eT>::value) {
      typedef blas_cxd T;
      arma_fortran(arma_zgemv)(transA, m, n, (const T*)alpha, (const T*)A, ldA,
                               (const T*)x, incx, (const T*)beta, (T*)y, incy);
    }
  }
#endif
}

template <typename eT>
inline void gemm(const char* transA, const char* transB, const blas_int* m,
                 const blas_int* n, const blas_int* k, const eT* alpha, const eT* A,
                 const blas_int* ldA, const eT* B, const blas_int* ldB, const eT* beta,
                 eT* C, const blas_int* ldC) {
  arma_type_check((is_supported_blas_type<eT>::value == false));

#if defined(ARMA_USE_FORTRAN_HIDDEN_ARGS)
  {
    if (is_float<eT>::value) {
      typedef float T;
      arma_fortran(arma_sgemm)(transA, transB, m, n, k, (const T*)alpha, (const T*)A, ldA,
                               (const T*)B, ldB, (const T*)beta, (T*)C, ldC, 1, 1);
    } else if (is_double<eT>::value) {
      typedef double T;
      arma_fortran(arma_dgemm)(transA, transB, m, n, k, (const T*)alpha, (const T*)A, ldA,
                               (const T*)B, ldB, (const T*)beta, (T*)C, ldC, 1, 1);
    } else if (is_cx_float<eT>::value) {
      typedef blas_cxf T;
      arma_fortran(arma_cgemm)(transA, transB, m, n, k, (const T*)alpha, (const T*)A, ldA,
                               (const T*)B, ldB, (const T*)beta, (T*)C, ldC, 1, 1);
    } else if (is_cx_double<eT>::value) {
      typedef blas_cxd T;
      arma_fortran(arma_zgemm)(transA, transB, m, n, k, (const T*)alpha, (const T*)A, ldA,
                               (const T*)B, ldB, (const T*)beta, (T*)C, ldC, 1, 1);
    }
  }
#else
  {
    if (is_float<eT>::value) {
      typedef float T;
      arma_fortran(arma_sgemm)(transA, transB, m, n, k, (const T*)alpha, (const T*)A, ldA,
                               (const T*)B, ldB, (const T*)beta, (T*)C, ldC);
    } else if (is_double<eT>::value) {
      typedef double T;
      arma_fortran(arma_dgemm)(transA, transB, m, n, k, (const T*)alpha, (const T*)A, ldA,
                               (const T*)B, ldB, (const T*)beta, (T*)C, ldC);
    } else if (is_cx_float<eT>::value) {
      typedef blas_cxf T;
      arma_fortran(arma_cgemm)(transA, transB, m, n, k, (const T*)alpha, (const T*)A, ldA,
                               (const T*)B, ldB, (const T*)beta, (T*)C, ldC);
    } else if (is_cx_double<eT>::value) {
      typedef blas_cxd T;
      arma_fortran(arma_zgemm)(transA, transB, m, n, k, (const T*)alpha, (const T*)A, ldA,
                               (const T*)B, ldB, (const T*)beta, (T*)C, ldC);
    }
  }
#endif
}

template <typename eT>
inline void syrk(const char* uplo, const char* transA, const blas_int* n,
                 const blas_int* k, const eT* alpha, const eT* A, const blas_int* ldA,
                 const eT* beta, eT* C, const blas_int* ldC) {
  arma_type_check((is_supported_blas_type<eT>::value == false));

#if defined(ARMA_USE_FORTRAN_HIDDEN_ARGS)
  {
    if (is_float<eT>::value) {
      typedef float T;
      arma_fortran(arma_ssyrk)(uplo, transA, n, k, (const T*)alpha, (const T*)A, ldA,
                               (const T*)beta, (T*)C, ldC, 1, 1);
    } else if (is_double<eT>::value) {
      typedef double T;
      arma_fortran(arma_dsyrk)(uplo, transA, n, k, (const T*)alpha, (const T*)A, ldA,
                               (const T*)beta, (T*)C, ldC, 1, 1);
    }
  }
#else
  {
    if (is_float<eT>::value) {
      typedef float T;
      arma_fortran(arma_ssyrk)(uplo, transA, n, k, (const T*)alpha, (const T*)A, ldA,
                               (const T*)beta, (T*)C, ldC);
    } else if (is_double<eT>::value) {
      typedef double T;
      arma_fortran(arma_dsyrk)(uplo, transA, n, k, (const T*)alpha, (const T*)A, ldA,
                               (const T*)beta, (T*)C, ldC);
    }
  }
#endif
}

template <typename T>
inline void herk(const char* uplo, const char* transA, const blas_int* n,
                 const blas_int* k, const T* alpha, const std::complex<T>* A,
                 const blas_int* ldA, const T* beta, std::complex<T>* C,
                 const blas_int* ldC) {
  arma_type_check((is_supported_blas_type<T>::value == false));

#if defined(ARMA_USE_FORTRAN_HIDDEN_ARGS)
  {
    if (is_float<T>::value) {
      typedef float TT;
      typedef blas_cxf cx_TT;
      arma_fortran(arma_cherk)(uplo, transA, n, k, (const TT*)alpha, (const cx_TT*)A, ldA,
                               (const TT*)beta, (cx_TT*)C, ldC, 1, 1);
    } else if (is_double<T>::value) {
      typedef double TT;
      typedef blas_cxd cx_TT;
      arma_fortran(arma_zherk)(uplo, transA, n, k, (const TT*)alpha, (const cx_TT*)A, ldA,
                               (const TT*)beta, (cx_TT*)C, ldC, 1, 1);
    }
  }
#else
  {
    if (is_float<T>::value) {
      typedef float TT;
      typedef blas_cxf cx_TT;
      arma_fortran(arma_cherk)(uplo, transA, n, k, (const TT*)alpha, (const cx_TT*)A, ldA,
                               (const TT*)beta, (cx_TT*)C, ldC);
    } else if (is_double<T>::value) {
      typedef double TT;
      typedef blas_cxd cx_TT;
      arma_fortran(arma_zherk)(uplo, transA, n, k, (const TT*)alpha, (const cx_TT*)A, ldA,
                               (const TT*)beta, (cx_TT*)C, ldC);
    }
  }
#endif
}

template <typename eT>
inline eT dot(const uword n_elem, const eT* x, const eT* y) {
  arma_type_check((is_supported_blas_type<eT>::value == false));

  if (is_float<eT>::value) {
#if defined(ARMA_BLAS_FLOAT_BUG)
    {
      if (n_elem == 0) {
        return eT(0);
      }

      const char trans = 'T';

      const blas_int m = blas_int(n_elem);
      const blas_int n = 1;
      const blas_int inc = 1;

      const eT alpha = eT(1);
      const eT beta = eT(0);

      eT result[2];  // paranoia: using two elements instead of one

      result[0] = eT(0);
      result[1] = eT(0);

      blas::gemv(&trans, &m, &n, &alpha, x, &m, y, &inc, &beta, &result[0], &inc);

      return result[0];
    }
#else
    {
      blas_int n = blas_int(n_elem);
      blas_int inc = 1;

      typedef float T;
      return eT(arma_fortran(arma_sdot)(&n, (const T*)x, &inc, (const T*)y, &inc));
    }
#endif
  } else if (is_double<eT>::value) {
    blas_int n = blas_int(n_elem);
    blas_int inc = 1;

    typedef double T;
    return eT(arma_fortran(arma_ddot)(&n, (const T*)x, &inc, (const T*)y, &inc));
  } else if ((is_cx_float<eT>::value) || (is_cx_double<eT>::value)) {
    if (n_elem == 0) {
      return eT(0);
    }

    // using gemv() workaround due to compatibility issues with cdotu() and zdotu()

    const char trans = 'T';

    const blas_int m = blas_int(n_elem);
    const blas_int n = 1;
    const blas_int inc = 1;

    const eT alpha = eT(1);
    const eT beta = eT(0);

    eT result[2];  // paranoia: using two elements instead of one

    result[0] = eT(0);
    result[1] = eT(0);

    blas::gemv(&trans, &m, &n, &alpha, x, &m, y, &inc, &beta, &result[0], &inc);

    return result[0];
  }

  return eT(0);
}

template <typename eT>
arma_inline eT asum(const uword n_elem, const eT* x) {
  arma_type_check((is_supported_blas_type<eT>::value == false));

  if (is_float<eT>::value) {
    // WARNING: sasum() from Accelerate framework (macOS) may return 'double' instead of
    // 'float'

    blas_int n = blas_int(n_elem);
    blas_int inc = 1;

    typedef float T;
    return arma_fortran(arma_sasum)(&n, (const T*)x, &inc);
  } else if (is_double<eT>::value) {
    blas_int n = blas_int(n_elem);
    blas_int inc = 1;

    typedef double T;
    return arma_fortran(arma_dasum)(&n, (const T*)x, &inc);
  }

  return eT(0);
}

template <typename eT>
arma_inline eT nrm2(const uword n_elem, const eT* x) {
  arma_type_check((is_supported_blas_type<eT>::value == false));

  if (is_float<eT>::value) {
    // WARNING: snrm2() from Accelerate framework (macOS) may return 'double' instead of
    // 'float'

    blas_int n = blas_int(n_elem);
    blas_int inc = 1;

    typedef float T;
    return arma_fortran(arma_snrm2)(&n, (const T*)x, &inc);
  } else if (is_double<eT>::value) {
    blas_int n = blas_int(n_elem);
    blas_int inc = 1;

    typedef double T;
    return arma_fortran(arma_dnrm2)(&n, (const T*)x, &inc);
  }

  return eT(0);
}

}  // namespace blas

#endif
