// 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_unique
//! @{

template <typename T1>
inline bool op_unique::apply_helper(Mat<typename T1::elem_type>& out, const Proxy<T1>& P,
                                    const bool P_is_row) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const uword n_elem = P.get_n_elem();

  if (n_elem == 0) {
    if (P_is_row) {
      out.set_size(1, 0);
    } else {
      out.set_size(0, 1);
    }

    return true;
  }

  if (n_elem == 1) {
    const eT tmp = (Proxy<T1>::use_at) ? P.at(0, 0) : P[0];

    out.set_size(1, 1);

    out[0] = tmp;

    return true;
  }

  Mat<eT> X(n_elem, 1, arma_nozeros_indicator());

  eT* X_mem = X.memptr();

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

    for (uword i = 0; i < n_elem; ++i) {
      const eT val = Pea[i];

      if (arma_isnan(val)) {
        out.soft_reset();
        return false;
      }

      X_mem[i] = val;
    }
  } else {
    const uword n_rows = P.get_n_rows();
    const uword n_cols = P.get_n_cols();

    for (uword col = 0; col < n_cols; ++col)
      for (uword row = 0; row < n_rows; ++row) {
        const eT val = P.at(row, col);

        if (arma_isnan(val)) {
          out.soft_reset();
          return false;
        }

        (*X_mem) = val;
        X_mem++;
      }

    X_mem = X.memptr();
  }

  arma_unique_comparator<eT> comparator;

  std::sort(X.begin(), X.end(), comparator);

  uword N_unique = 1;

  for (uword i = 1; i < n_elem; ++i) {
    const eT a = X_mem[i - 1];
    const eT b = X_mem[i];

    const eT diff = a - b;

    if (diff != eT(0)) {
      ++N_unique;
    }
  }

  if (P_is_row) {
    out.set_size(1, N_unique);
  } else {
    out.set_size(N_unique, 1);
  }

  eT* out_mem = out.memptr();

  if (n_elem > 0) {
    (*out_mem) = X_mem[0];
    out_mem++;
  }

  for (uword i = 1; i < n_elem; ++i) {
    const eT a = X_mem[i - 1];
    const eT b = X_mem[i];

    const eT diff = a - b;

    if (diff != eT(0)) {
      (*out_mem) = b;
      out_mem++;
    }
  }

  return true;
}

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

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

  const bool all_non_nan = op_unique::apply_helper(out, P, false);

  arma_conform_check((all_non_nan == false), "unique(): detected NaN");
}

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

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

  const bool P_is_row = (T1::is_xvec) ? bool(P.get_n_rows() == 1) : bool(T1::is_row);

  const bool all_non_nan = op_unique::apply_helper(out, P, P_is_row);

  arma_conform_check((all_non_nan == false), "unique(): detected NaN");
}

//! @}
