// 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.
// ------------------------------------------------------------------------

//! \addtogroup op_diagmat
//! @{

template <typename T1>
inline void op_diagmat::apply(Mat<typename T1::elem_type>& out,
                              const Op<T1, op_diagmat>& X) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  if (is_Mat<T1>::value) {
    // allow detection of in-place operation

    const unwrap<T1> U(X.m);
    const Mat<eT>& A = U.M;

    if (&out != &A)  // no aliasing
    {
      const Proxy<Mat<eT> > P(A);

      op_diagmat::apply(out, P);
    } else  // we have aliasing
    {
      const uword n_rows = out.n_rows;
      const uword n_cols = out.n_cols;

      if ((n_rows == 1) || (n_cols == 1))  // create diagonal matrix from vector
      {
        const eT* out_mem = out.memptr();
        const uword N = out.n_elem;

        Mat<eT> tmp(N, N, arma_zeros_indicator());

        for (uword i = 0; i < N; ++i) {
          tmp.at(i, i) = out_mem[i];
        }

        out.steal_mem(tmp);
      } else  // create diagonal matrix from matrix
      {
        const uword N = (std::min)(n_rows, n_cols);

        for (uword i = 0; i < n_cols; ++i) {
          if (i < N) {
            eT& out_ii = out.at(i, i);

            const eT val = out_ii;

            arrayops::fill_zeros(out.colptr(i), n_rows);

            out_ii = val;
          } else {
            arrayops::fill_zeros(out.colptr(i), n_rows);
          }
        }
      }
    }
  } else {
    const Proxy<T1> P(X.m);

    if (P.is_alias(out)) {
      Mat<eT> tmp;

      op_diagmat::apply(tmp, P);

      out.steal_mem(tmp);
    } else {
      op_diagmat::apply(out, P);
    }
  }
}

template <typename T1>
inline void op_diagmat::apply(Mat<typename T1::elem_type>& out, const Proxy<T1>& P) {
  arma_debug_sigprint();

  const uword n_rows = P.get_n_rows();
  const uword n_cols = P.get_n_cols();
  const uword n_elem = P.get_n_elem();

  if (n_elem == 0) {
    out.reset();
    return;
  }

  const bool P_is_vec = (T1::is_row) || (T1::is_col) || (n_rows == 1) || (n_cols == 1);

  if (P_is_vec) {
    out.zeros(n_elem, n_elem);

    if (Proxy<T1>::use_at == false) {
      typename Proxy<T1>::ea_type Pea = P.get_ea();

      for (uword i = 0; i < n_elem; ++i) {
        out.at(i, i) = Pea[i];
      }
    } else {
      if (n_rows == 1) {
        for (uword i = 0; i < n_elem; ++i) {
          out.at(i, i) = P.at(0, i);
        }
      } else {
        for (uword i = 0; i < n_elem; ++i) {
          out.at(i, i) = P.at(i, 0);
        }
      }
    }
  } else  // P represents a matrix
  {
    out.zeros(n_rows, n_cols);

    const uword N = (std::min)(n_rows, n_cols);

    for (uword i = 0; i < N; ++i) {
      out.at(i, i) = P.at(i, i);
    }
  }
}

template <typename T1, typename T2>
inline void op_diagmat::apply(Mat<typename T1::elem_type>& out,
                              const Op<Glue<T1, T2, glue_times>, op_diagmat>& X) {
  arma_debug_sigprint();

  op_diagmat::apply_times(out, X.m.A, X.m.B);
}

template <typename T1, typename T2>
inline void op_diagmat::apply_times(
    Mat<typename T1::elem_type>& actual_out, const T1& X, const T2& Y,
    const typename arma_not_cx<typename T1::elem_type>::result* junk) {
  arma_debug_sigprint();
  arma_ignore(junk);

  typedef typename T1::elem_type eT;

  const partial_unwrap<T1> UA(X);
  const partial_unwrap<T2> UB(Y);

  const typename partial_unwrap<T1>::stored_type& A = UA.M;
  const typename partial_unwrap<T2>::stored_type& B = UB.M;

  arma_conform_assert_trans_mul_size<partial_unwrap<T1>::do_trans,
                                     partial_unwrap<T2>::do_trans>(
      A.n_rows, A.n_cols, B.n_rows, B.n_cols, "matrix multiplication");

  constexpr bool use_alpha = partial_unwrap<T1>::do_times || partial_unwrap<T2>::do_times;
  const eT alpha = use_alpha ? (UA.get_val() * UB.get_val()) : eT(0);

  const uword A_n_rows = A.n_rows;
  const uword A_n_cols = A.n_cols;

  const uword B_n_rows = B.n_rows;
  const uword B_n_cols = B.n_cols;

  // check if the multiplication results in a vector

  if ((partial_unwrap<T1>::do_trans == false) &&
      (partial_unwrap<T2>::do_trans == false)) {
    if ((A_n_rows == 1) || (B_n_cols == 1)) {
      arma_debug_print("trans_A = false; trans_B = false; vector result");

      const Mat<eT> C = A * B;
      const eT* C_mem = C.memptr();
      const uword N = C.n_elem;

      actual_out.zeros(N, N);

      for (uword i = 0; i < N; ++i) {
        actual_out.at(i, i) = (use_alpha) ? eT(alpha * C_mem[i]) : eT(C_mem[i]);
      }

      return;
    }
  } else if ((partial_unwrap<T1>::do_trans == true) &&
             (partial_unwrap<T2>::do_trans == false)) {
    if ((A_n_cols == 1) || (B_n_cols == 1)) {
      arma_debug_print("trans_A = true; trans_B = false; vector result");

      const Mat<eT> C = trans(A) * B;
      const eT* C_mem = C.memptr();
      const uword N = C.n_elem;

      actual_out.zeros(N, N);

      for (uword i = 0; i < N; ++i) {
        actual_out.at(i, i) = (use_alpha) ? eT(alpha * C_mem[i]) : eT(C_mem[i]);
      }

      return;
    }
  } else if ((partial_unwrap<T1>::do_trans == false) &&
             (partial_unwrap<T2>::do_trans == true)) {
    if ((A_n_rows == 1) || (B_n_rows == 1)) {
      arma_debug_print("trans_A = false; trans_B = true; vector result");

      const Mat<eT> C = A * trans(B);
      const eT* C_mem = C.memptr();
      const uword N = C.n_elem;

      actual_out.zeros(N, N);

      for (uword i = 0; i < N; ++i) {
        actual_out.at(i, i) = (use_alpha) ? eT(alpha * C_mem[i]) : eT(C_mem[i]);
      }

      return;
    }
  } else if ((partial_unwrap<T1>::do_trans == true) &&
             (partial_unwrap<T2>::do_trans == true)) {
    if ((A_n_cols == 1) || (B_n_rows == 1)) {
      arma_debug_print("trans_A = true; trans_B = true; vector result");

      const Mat<eT> C = trans(A) * trans(B);
      const eT* C_mem = C.memptr();
      const uword N = C.n_elem;

      actual_out.zeros(N, N);

      for (uword i = 0; i < N; ++i) {
        actual_out.at(i, i) = (use_alpha) ? eT(alpha * C_mem[i]) : eT(C_mem[i]);
      }

      return;
    }
  }

  // if we got to this point, the multiplication results in a matrix

  const bool is_alias = (UA.is_alias(actual_out) || UB.is_alias(actual_out));

  Mat<eT> tmp;
  Mat<eT>& out = (is_alias) ? tmp : actual_out;

  if ((partial_unwrap<T1>::do_trans == false) &&
      (partial_unwrap<T2>::do_trans == false)) {
    arma_debug_print("trans_A = false; trans_B = false; matrix result");

    out.zeros(A_n_rows, B_n_cols);

    const uword N = (std::min)(A_n_rows, B_n_cols);

    for (uword k = 0; k < N; ++k) {
      eT acc1 = eT(0);
      eT acc2 = eT(0);

      const eT* B_colptr = B.colptr(k);

      // condition: A_n_cols = B_n_rows

      uword j;

      for (j = 1; j < A_n_cols; j += 2) {
        const uword i = (j - 1);

        const eT tmp_i = B_colptr[i];
        const eT tmp_j = B_colptr[j];

        acc1 += A.at(k, i) * tmp_i;
        acc2 += A.at(k, j) * tmp_j;
      }

      const uword i = (j - 1);

      if (i < A_n_cols) {
        acc1 += A.at(k, i) * B_colptr[i];
      }

      const eT acc = acc1 + acc2;

      out.at(k, k) = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  } else if ((partial_unwrap<T1>::do_trans == true) &&
             (partial_unwrap<T2>::do_trans == false)) {
    arma_debug_print("trans_A = true; trans_B = false; matrix result");

    out.zeros(A_n_cols, B_n_cols);

    const uword N = (std::min)(A_n_cols, B_n_cols);

    for (uword k = 0; k < N; ++k) {
      const eT* A_colptr = A.colptr(k);
      const eT* B_colptr = B.colptr(k);

      // condition: A_n_rows = B_n_rows

      const eT acc = op_dot::direct_dot(A_n_rows, A_colptr, B_colptr);

      out.at(k, k) = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  } else if ((partial_unwrap<T1>::do_trans == false) &&
             (partial_unwrap<T2>::do_trans == true)) {
    arma_debug_print("trans_A = false; trans_B = true; matrix result");

    out.zeros(A_n_rows, B_n_rows);

    const uword N = (std::min)(A_n_rows, B_n_rows);

    for (uword k = 0; k < N; ++k) {
      eT acc = eT(0);

      // condition: A_n_cols = B_n_cols

      for (uword i = 0; i < A_n_cols; ++i) {
        acc += A.at(k, i) * B.at(k, i);
      }

      out.at(k, k) = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  } else if ((partial_unwrap<T1>::do_trans == true) &&
             (partial_unwrap<T2>::do_trans == true)) {
    arma_debug_print("trans_A = true; trans_B = true; matrix result");

    out.zeros(A_n_cols, B_n_rows);

    const uword N = (std::min)(A_n_cols, B_n_rows);

    for (uword k = 0; k < N; ++k) {
      eT acc = eT(0);

      const eT* A_colptr = A.colptr(k);

      // condition: A_n_rows = B_n_cols

      for (uword i = 0; i < A_n_rows; ++i) {
        acc += A_colptr[i] * B.at(k, i);
      }

      out.at(k, k) = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  }

  if (is_alias) {
    actual_out.steal_mem(tmp);
  }
}

template <typename T1, typename T2>
inline void op_diagmat::apply_times(
    Mat<typename T1::elem_type>& actual_out, const T1& X, const T2& Y,
    const typename arma_cx_only<typename T1::elem_type>::result* junk) {
  arma_debug_sigprint();
  arma_ignore(junk);

  typedef typename T1::pod_type T;
  typedef typename T1::elem_type eT;

  const partial_unwrap<T1> UA(X);
  const partial_unwrap<T2> UB(Y);

  const typename partial_unwrap<T1>::stored_type& A = UA.M;
  const typename partial_unwrap<T2>::stored_type& B = UB.M;

  arma_conform_assert_trans_mul_size<partial_unwrap<T1>::do_trans,
                                     partial_unwrap<T2>::do_trans>(
      A.n_rows, A.n_cols, B.n_rows, B.n_cols, "matrix multiplication");

  constexpr bool use_alpha = partial_unwrap<T1>::do_times || partial_unwrap<T2>::do_times;
  const eT alpha = use_alpha ? (UA.get_val() * UB.get_val()) : eT(0);

  const uword A_n_rows = A.n_rows;
  const uword A_n_cols = A.n_cols;

  const uword B_n_rows = B.n_rows;
  const uword B_n_cols = B.n_cols;

  // check if the multiplication results in a vector

  if ((partial_unwrap<T1>::do_trans == false) &&
      (partial_unwrap<T2>::do_trans == false)) {
    if ((A_n_rows == 1) || (B_n_cols == 1)) {
      arma_debug_print("trans_A = false; trans_B = false; vector result");

      const Mat<eT> C = A * B;
      const eT* C_mem = C.memptr();
      const uword N = C.n_elem;

      actual_out.zeros(N, N);

      for (uword i = 0; i < N; ++i) {
        actual_out.at(i, i) = (use_alpha) ? eT(alpha * C_mem[i]) : eT(C_mem[i]);
      }

      return;
    }
  } else if ((partial_unwrap<T1>::do_trans == true) &&
             (partial_unwrap<T2>::do_trans == false)) {
    if ((A_n_cols == 1) || (B_n_cols == 1)) {
      arma_debug_print("trans_A = true; trans_B = false; vector result");

      const Mat<eT> C = trans(A) * B;
      const eT* C_mem = C.memptr();
      const uword N = C.n_elem;

      actual_out.zeros(N, N);

      for (uword i = 0; i < N; ++i) {
        actual_out.at(i, i) = (use_alpha) ? eT(alpha * C_mem[i]) : eT(C_mem[i]);
      }

      return;
    }
  } else if ((partial_unwrap<T1>::do_trans == false) &&
             (partial_unwrap<T2>::do_trans == true)) {
    if ((A_n_rows == 1) || (B_n_rows == 1)) {
      arma_debug_print("trans_A = false; trans_B = true; vector result");

      const Mat<eT> C = A * trans(B);
      const eT* C_mem = C.memptr();
      const uword N = C.n_elem;

      actual_out.zeros(N, N);

      for (uword i = 0; i < N; ++i) {
        actual_out.at(i, i) = (use_alpha) ? eT(alpha * C_mem[i]) : eT(C_mem[i]);
      }

      return;
    }
  } else if ((partial_unwrap<T1>::do_trans == true) &&
             (partial_unwrap<T2>::do_trans == true)) {
    if ((A_n_cols == 1) || (B_n_rows == 1)) {
      arma_debug_print("trans_A = true; trans_B = true; vector result");

      const Mat<eT> C = trans(A) * trans(B);
      const eT* C_mem = C.memptr();
      const uword N = C.n_elem;

      actual_out.zeros(N, N);

      for (uword i = 0; i < N; ++i) {
        actual_out.at(i, i) = (use_alpha) ? eT(alpha * C_mem[i]) : eT(C_mem[i]);
      }

      return;
    }
  }

  // if we got to this point, the multiplication results in a matrix

  const bool is_alias = (UA.is_alias(actual_out) || UB.is_alias(actual_out));

  Mat<eT> tmp;
  Mat<eT>& out = (is_alias) ? tmp : actual_out;

  if ((partial_unwrap<T1>::do_trans == false) &&
      (partial_unwrap<T2>::do_trans == false)) {
    arma_debug_print("trans_A = false; trans_B = false; matrix result");

    out.zeros(A_n_rows, B_n_cols);

    const uword N = (std::min)(A_n_rows, B_n_cols);

    for (uword k = 0; k < N; ++k) {
      T acc_real = T(0);
      T acc_imag = T(0);

      const eT* B_colptr = B.colptr(k);

      // condition: A_n_cols = B_n_rows

      for (uword i = 0; i < A_n_cols; ++i) {
        // acc += A.at(k, i) * B_colptr[i];

        const std::complex<T>& xx = A.at(k, i);
        const std::complex<T>& yy = B_colptr[i];

        const T a = xx.real();
        const T b = xx.imag();

        const T c = yy.real();
        const T d = yy.imag();

        acc_real += (a * c) - (b * d);
        acc_imag += (a * d) + (b * c);
      }

      const eT acc = std::complex<T>(acc_real, acc_imag);

      out.at(k, k) = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  } else if ((partial_unwrap<T1>::do_trans == true) &&
             (partial_unwrap<T2>::do_trans == false)) {
    arma_debug_print("trans_A = true; trans_B = false; matrix result");

    out.zeros(A_n_cols, B_n_cols);

    const uword N = (std::min)(A_n_cols, B_n_cols);

    for (uword k = 0; k < N; ++k) {
      T acc_real = T(0);
      T acc_imag = T(0);

      const eT* A_colptr = A.colptr(k);
      const eT* B_colptr = B.colptr(k);

      // condition: A_n_rows = B_n_rows

      for (uword i = 0; i < A_n_rows; ++i) {
        // acc += std::conj(A_colptr[i]) * B_colptr[i];

        const std::complex<T>& xx = A_colptr[i];
        const std::complex<T>& yy = B_colptr[i];

        const T a = xx.real();
        const T b = xx.imag();

        const T c = yy.real();
        const T d = yy.imag();

        // take into account the complex conjugate of xx

        acc_real += (a * c) + (b * d);
        acc_imag += (a * d) - (b * c);
      }

      const eT acc = std::complex<T>(acc_real, acc_imag);

      out.at(k, k) = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  } else if ((partial_unwrap<T1>::do_trans == false) &&
             (partial_unwrap<T2>::do_trans == true)) {
    arma_debug_print("trans_A = false; trans_B = true; matrix result");

    out.zeros(A_n_rows, B_n_rows);

    const uword N = (std::min)(A_n_rows, B_n_rows);

    for (uword k = 0; k < N; ++k) {
      T acc_real = T(0);
      T acc_imag = T(0);

      // condition: A_n_cols = B_n_cols

      for (uword i = 0; i < A_n_cols; ++i) {
        // acc += A.at(k,i) * std::conj(B.at(k,i));

        const std::complex<T>& xx = A.at(k, i);
        const std::complex<T>& yy = B.at(k, i);

        const T a = xx.real();
        const T b = xx.imag();

        const T c = yy.real();
        const T d = -yy.imag();  // take the conjugate

        acc_real += (a * c) - (b * d);
        acc_imag += (a * d) + (b * c);
      }

      const eT acc = std::complex<T>(acc_real, acc_imag);

      out.at(k, k) = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  } else if ((partial_unwrap<T1>::do_trans == true) &&
             (partial_unwrap<T2>::do_trans == true)) {
    arma_debug_print("trans_A = true; trans_B = true; matrix result");

    out.zeros(A_n_cols, B_n_rows);

    const uword N = (std::min)(A_n_cols, B_n_rows);

    for (uword k = 0; k < N; ++k) {
      T acc_real = T(0);
      T acc_imag = T(0);

      const eT* A_colptr = A.colptr(k);

      // condition: A_n_rows = B_n_cols

      for (uword i = 0; i < A_n_rows; ++i) {
        // acc += std::conj(A_colptr[i]) * std::conj(B.at(k,i));

        const std::complex<T>& xx = A_colptr[i];
        const std::complex<T>& yy = B.at(k, i);

        const T a = xx.real();
        const T b = -xx.imag();  // take the conjugate

        const T c = yy.real();
        const T d = -yy.imag();  // take the conjugate

        acc_real += (a * c) - (b * d);
        acc_imag += (a * d) + (b * c);
      }

      const eT acc = std::complex<T>(acc_real, acc_imag);

      out.at(k, k) = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  }

  if (is_alias) {
    actual_out.steal_mem(tmp);
  }
}

//
//
//

template <typename T1>
inline void op_diagmat2::apply(Mat<typename T1::elem_type>& out,
                               const Op<T1, op_diagmat2>& X) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const uword row_offset = X.aux_uword_a;
  const uword col_offset = X.aux_uword_b;

  const Proxy<T1> P(X.m);

  if (P.is_alias(out)) {
    Mat<eT> tmp;

    op_diagmat2::apply(tmp, P, row_offset, col_offset);

    out.steal_mem(tmp);
  } else {
    op_diagmat2::apply(out, P, row_offset, col_offset);
  }
}

template <typename T1>
inline void op_diagmat2::apply(Mat<typename T1::elem_type>& out, const Proxy<T1>& P,
                               const uword row_offset, const uword col_offset) {
  arma_debug_sigprint();

  const uword n_rows = P.get_n_rows();
  const uword n_cols = P.get_n_cols();
  const uword n_elem = P.get_n_elem();

  if (n_elem == 0) {
    out.reset();
    return;
  }

  const bool P_is_vec = (T1::is_row) || (T1::is_col) || (n_rows == 1) || (n_cols == 1);

  if (P_is_vec) {
    const uword n_pad = (std::max)(row_offset, col_offset);

    out.zeros(n_elem + n_pad, n_elem + n_pad);

    if (Proxy<T1>::use_at == false) {
      typename Proxy<T1>::ea_type Pea = P.get_ea();

      for (uword i = 0; i < n_elem; ++i) {
        out.at(row_offset + i, col_offset + i) = Pea[i];
      }
    } else {
      if (n_rows == 1) {
        for (uword i = 0; i < n_elem; ++i) {
          out.at(row_offset + i, col_offset + i) = P.at(0, i);
        }
      } else {
        for (uword i = 0; i < n_elem; ++i) {
          out.at(row_offset + i, col_offset + i) = P.at(i, 0);
        }
      }
    }
  } else  // P represents a matrix
  {
    arma_conform_check_bounds(((row_offset > 0) && (row_offset >= n_rows)) ||
                                  ((col_offset > 0) && (col_offset >= n_cols)),
                              "diagmat(): requested diagonal out of bounds");

    out.zeros(n_rows, n_cols);

    const uword N = (std::min)(n_rows - row_offset, n_cols - col_offset);

    for (uword i = 0; i < N; ++i) {
      const uword row = i + row_offset;
      const uword col = i + col_offset;

      out.at(row, col) = P.at(row, col);
    }
  }
}

//! @}
