// 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 glue_atan2
//! @{

template <typename T1, typename T2>
inline void glue_atan2::apply(Mat<typename T1::elem_type>& out,
                              const Glue<T1, T2, glue_atan2>& expr) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const Proxy<T1> P1(expr.A);
  const Proxy<T2> P2(expr.B);

  arma_assert_same_size(P1, P2, "atan2()");

  const bool bad_alias = ((Proxy<T1>::has_subview && P1.is_alias(out)) ||
                          (Proxy<T2>::has_subview && P2.is_alias(out)));

  if (bad_alias == false) {
    glue_atan2::apply_noalias(out, P1, P2);
  } else {
    Mat<eT> tmp;

    glue_atan2::apply_noalias(tmp, P1, P2);

    out.steal_mem(tmp);
  }
}

template <typename T1, typename T2>
inline void glue_atan2::apply_noalias(Mat<typename T1::elem_type>& out,
                                      const Proxy<T1>& P1, const Proxy<T2>& P2) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const uword n_rows = P1.get_n_rows();
  const uword n_cols = P1.get_n_cols();
  const uword n_elem = P1.get_n_elem();

  out.set_size(n_rows, n_cols);

  eT* out_mem = out.memptr();

  const bool use_mp = arma_config::openmp &&
                      mp_gate<eT, (Proxy<T1>::use_mp || Proxy<T2>::use_mp)>::eval(n_elem);
  constexpr bool use_at = Proxy<T1>::use_at || Proxy<T2>::use_at;

  if (use_at == false) {
    typename Proxy<T1>::ea_type eaP1 = P1.get_ea();
    typename Proxy<T2>::ea_type eaP2 = P2.get_ea();

    if (use_mp) {
#if defined(ARMA_USE_OPENMP)
      {
        const int n_threads = mp_thread_limit::get();
#pragma omp parallel for schedule(static) num_threads(n_threads)
        for (uword i = 0; i < n_elem; ++i) {
          out_mem[i] = std::atan2(eaP1[i], eaP2[i]);
        }
      }
#endif
    } else {
      for (uword i = 0; i < n_elem; ++i) {
        out_mem[i] = std::atan2(eaP1[i], eaP2[i]);
      }
    }
  } else {
    if (use_mp) {
      const unwrap<typename Proxy<T1>::stored_type> U1(P1.Q);
      const unwrap<typename Proxy<T2>::stored_type> U2(P2.Q);

      out = arma::atan2(U1.M, U2.M);
    } else {
      for (uword col = 0; col < n_cols; ++col)
        for (uword row = 0; row < n_rows; ++row) {
          *out_mem = std::atan2(P1.at(row, col), P2.at(row, col));
          out_mem++;
        }
    }
  }
}

template <typename T1, typename T2>
inline void glue_atan2::apply(Cube<typename T1::elem_type>& out,
                              const GlueCube<T1, T2, glue_atan2>& expr) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const ProxyCube<T1> P1(expr.A);
  const ProxyCube<T2> P2(expr.B);

  arma_assert_same_size(P1, P2, "atan2()");

  const bool bad_alias = ((ProxyCube<T1>::has_subview && P1.is_alias(out)) ||
                          (ProxyCube<T2>::has_subview && P2.is_alias(out)));

  if (bad_alias == false) {
    glue_atan2::apply_noalias(out, P1, P2);
  } else {
    Cube<eT> tmp;

    glue_atan2::apply_noalias(tmp, P1, P2);

    out.steal_mem(tmp);
  }
}

template <typename T1, typename T2>
inline void glue_atan2::apply_noalias(Cube<typename T1::elem_type>& out,
                                      const ProxyCube<T1>& P1, const ProxyCube<T2>& P2) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const uword n_rows = P1.get_n_rows();
  const uword n_cols = P1.get_n_cols();
  const uword n_slices = P1.get_n_slices();
  const uword n_elem = P1.get_n_elem();

  out.set_size(n_rows, n_cols, n_slices);

  eT* out_mem = out.memptr();

  const bool use_mp =
      arma_config::openmp &&
      mp_gate<eT, (ProxyCube<T1>::use_mp || ProxyCube<T2>::use_mp)>::eval(n_elem);
  constexpr bool use_at = ProxyCube<T1>::use_at || ProxyCube<T2>::use_at;

  if (use_at == false) {
    typename ProxyCube<T1>::ea_type eaP1 = P1.get_ea();
    typename ProxyCube<T2>::ea_type eaP2 = P2.get_ea();

    if (use_mp) {
#if defined(ARMA_USE_OPENMP)
      {
        const int n_threads = mp_thread_limit::get();
#pragma omp parallel for schedule(static) num_threads(n_threads)
        for (uword i = 0; i < n_elem; ++i) {
          out_mem[i] = std::atan2(eaP1[i], eaP2[i]);
        }
      }
#endif
    } else {
      for (uword i = 0; i < n_elem; ++i) {
        out_mem[i] = std::atan2(eaP1[i], eaP2[i]);
      }
    }
  } else {
    if (use_mp) {
      const unwrap_cube<typename ProxyCube<T1>::stored_type> U1(P1.Q);
      const unwrap_cube<typename ProxyCube<T2>::stored_type> U2(P2.Q);

      out = arma::atan2(U1.M, U2.M);
    } else {
      for (uword slice = 0; slice < n_slices; ++slice)
        for (uword col = 0; col < n_cols; ++col)
          for (uword row = 0; row < n_rows; ++row) {
            *out_mem = std::atan2(P1.at(row, col, slice), P2.at(row, col, slice));
            out_mem++;
          }
    }
  }
}

//! @}
