// 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 operator_minus
//! @{

//! unary -
template <typename T1>
arma_inline typename enable_if2<is_arma_type<T1>::value, const eOp<T1, eop_neg> >::result
operator-(const T1& X) {
  arma_debug_sigprint();

  return eOp<T1, eop_neg>(X);
}

// //! unary -
// template<typename T1>
// arma_inline
// typename
// enable_if2< (is_arma_type<T1>::value && is_signed<typename T1::elem_type>::value),
// const eOp<T1, eop_neg> >::result operator- (const T1& X)
//   {
//   arma_debug_sigprint();
//
//   return eOp<T1,eop_neg>(X);
//   }
//
//
//
// template<typename T1>
// arma_inline
// typename enable_if2< (is_arma_type<T1>::value && (is_signed<typename
// T1::elem_type>::value == false)), const eOp<T1, eop_scalar_times> >::result operator-
// (const T1& X)
//   {
//   arma_debug_sigprint();
//
//   typedef typename T1::elem_type eT;
//
//   return eOp<T1, eop_scalar_times>(X, eT(-1));
//   }

//! Base - scalar
template <typename T1>
arma_inline typename enable_if2<is_arma_type<T1>::value,
                                const eOp<T1, eop_scalar_minus_post> >::result
operator-(const T1& X, const typename T1::elem_type k) {
  arma_debug_sigprint();

  return eOp<T1, eop_scalar_minus_post>(X, k);
}

//! scalar - Base
template <typename T1>
arma_inline typename enable_if2<is_arma_type<T1>::value,
                                const eOp<T1, eop_scalar_minus_pre> >::result
operator-(const typename T1::elem_type k, const T1& X) {
  arma_debug_sigprint();

  return eOp<T1, eop_scalar_minus_pre>(X, k);
}

//! complex scalar - non-complex Base
template <typename T1>
arma_inline
    typename enable_if2<(is_arma_type<T1>::value && is_cx<typename T1::elem_type>::no),
                        const mtOp<typename std::complex<typename T1::pod_type>, T1,
                                   op_cx_scalar_minus_pre> >::result
    operator-(const std::complex<typename T1::pod_type>& k, const T1& X) {
  arma_debug_sigprint();

  return mtOp<typename std::complex<typename T1::pod_type>, T1, op_cx_scalar_minus_pre>(
      'j', X, k);
}

//! non-complex Base - complex scalar
template <typename T1>
arma_inline
    typename enable_if2<(is_arma_type<T1>::value && is_cx<typename T1::elem_type>::no),
                        const mtOp<typename std::complex<typename T1::pod_type>, T1,
                                   op_cx_scalar_minus_post> >::result
    operator-(const T1& X, const std::complex<typename T1::pod_type>& k) {
  arma_debug_sigprint();

  return mtOp<typename std::complex<typename T1::pod_type>, T1, op_cx_scalar_minus_post>(
      'j', X, k);
}

//! subtraction of Base objects with same element type
template <typename T1, typename T2>
arma_inline typename enable_if2<
    is_arma_type<T1>::value && is_arma_type<T2>::value &&
        is_same_type<typename T1::elem_type, typename T2::elem_type>::value,
    const eGlue<T1, T2, eglue_minus> >::result
operator-(const T1& X, const T2& Y) {
  arma_debug_sigprint();

  return eGlue<T1, T2, eglue_minus>(X, Y);
}

//! subtraction of Base objects with different element types
template <typename T1, typename T2>
inline typename enable_if2<
    (is_arma_type<T1>::value && is_arma_type<T2>::value &&
     (is_same_type<typename T1::elem_type, typename T2::elem_type>::no)),
    const mtGlue<
        typename promote_type<typename T1::elem_type, typename T2::elem_type>::result, T1,
        T2, glue_mixed_minus> >::result
operator-(const T1& X, const T2& Y) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT1;
  typedef typename T2::elem_type eT2;

  typedef typename promote_type<eT1, eT2>::result out_eT;

  promote_type<eT1, eT2>::check();

  return mtGlue<out_eT, T1, T2, glue_mixed_minus>(X, Y);
}

//! unary "-" for sparse objects
template <typename T1>
inline typename enable_if2<is_arma_sparse_type<T1>::value &&
                               is_signed<typename T1::elem_type>::value,
                           SpOp<T1, spop_scalar_times> >::result
operator-(const T1& X) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  return SpOp<T1, spop_scalar_times>(X, eT(-1));
}

//! subtraction of two sparse objects
template <typename T1, typename T2>
inline typename enable_if2<
    (is_arma_sparse_type<T1>::value && is_arma_sparse_type<T2>::value &&
     is_same_type<typename T1::elem_type, typename T2::elem_type>::value),
    const SpGlue<T1, T2, spglue_minus> >::result
operator-(const T1& X, const T2& Y) {
  arma_debug_sigprint();

  return SpGlue<T1, T2, spglue_minus>(X, Y);
}

//! subtraction of one sparse and one dense object
template <typename T1, typename T2>
inline typename enable_if2<
    (is_arma_sparse_type<T1>::value && is_arma_type<T2>::value &&
     is_same_type<typename T1::elem_type, typename T2::elem_type>::value),
    Mat<typename T1::elem_type> >::result
operator-(const T1& x, const T2& y) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const SpProxy<T1> pa(x);

  const quasi_unwrap<T2> UB(y);
  const Mat<eT>& B = UB.M;

  Mat<eT> result = -B;

  arma_conform_assert_same_size(pa.get_n_rows(), pa.get_n_cols(), result.n_rows,
                                result.n_cols, "subtraction");

  typename SpProxy<T1>::const_iterator_type it = pa.begin();
  typename SpProxy<T1>::const_iterator_type it_end = pa.end();

  for (; it != it_end; ++it) {
    const uword r = it.row();
    const uword c = it.col();

    result.at(r, c) = (*it) - B.at(r, c);
  }

  return result;
}

//! subtraction of one dense and one sparse object
template <typename T1, typename T2>
inline typename enable_if2<
    (is_arma_type<T1>::value && is_arma_sparse_type<T2>::value &&
     is_same_type<typename T1::elem_type, typename T2::elem_type>::value),
    Mat<typename T1::elem_type> >::result
operator-(const T1& x, const T2& y) {
  arma_debug_sigprint();

  Mat<typename T1::elem_type> result(x);

  const SpProxy<T2> pb(y);

  arma_conform_assert_same_size(result.n_rows, result.n_cols, pb.get_n_rows(),
                                pb.get_n_cols(), "subtraction");

  typename SpProxy<T2>::const_iterator_type it = pb.begin();
  typename SpProxy<T2>::const_iterator_type it_end = pb.end();

  while (it != it_end) {
    result.at(it.row(), it.col()) -= (*it);
    ++it;
  }

  return result;
}

//! subtraction of two sparse objects with different element types
template <typename T1, typename T2>
inline typename enable_if2<
    (is_arma_sparse_type<T1>::value && is_arma_sparse_type<T2>::value &&
     is_same_type<typename T1::elem_type, typename T2::elem_type>::no),
    const mtSpGlue<
        typename promote_type<typename T1::elem_type, typename T2::elem_type>::result, T1,
        T2, spglue_minus_mixed> >::result
operator-(const T1& X, const T2& Y) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT1;
  typedef typename T2::elem_type eT2;

  typedef typename promote_type<eT1, eT2>::result out_eT;

  promote_type<eT1, eT2>::check();

  return mtSpGlue<out_eT, T1, T2, spglue_minus_mixed>(X, Y);
}

//! subtraction of sparse and non-sparse objects with different element types
template <typename T1, typename T2>
inline typename enable_if2<
    (is_arma_sparse_type<T1>::value && is_arma_type<T2>::value &&
     is_same_type<typename T1::elem_type, typename T2::elem_type>::no),
    Mat<typename promote_type<typename T1::elem_type, typename T2::elem_type>::result> >::
    result
    operator-(const T1& x, const T2& y) {
  arma_debug_sigprint();

  Mat<typename promote_type<typename T1::elem_type, typename T2::elem_type>::result> out;

  spglue_minus_mixed::sparse_minus_dense(out, x, y);

  return out;
}

//! subtraction of sparse and non-sparse objects with different element types
template <typename T1, typename T2>
inline typename enable_if2<
    (is_arma_type<T1>::value && is_arma_sparse_type<T2>::value &&
     is_same_type<typename T1::elem_type, typename T2::elem_type>::no),
    Mat<typename promote_type<typename T1::elem_type, typename T2::elem_type>::result> >::
    result
    operator-(const T1& x, const T2& y) {
  arma_debug_sigprint();

  Mat<typename promote_type<typename T1::elem_type, typename T2::elem_type>::result> out;

  spglue_minus_mixed::dense_minus_sparse(out, x, y);

  return out;
}

//! sparse - scalar
template <typename T1>
arma_inline typename enable_if2<is_arma_sparse_type<T1>::value,
                                const SpToDOp<T1, op_sp_minus_post> >::result
operator-(const T1& X, const typename T1::elem_type k) {
  arma_debug_sigprint();

  return SpToDOp<T1, op_sp_minus_post>(X, k);
}

//! scalar - sparse
template <typename T1>
arma_inline typename enable_if2<is_arma_sparse_type<T1>::value,
                                const SpToDOp<T1, op_sp_minus_pre> >::result
operator-(const typename T1::elem_type k, const T1& X) {
  arma_debug_sigprint();

  return SpToDOp<T1, op_sp_minus_pre>(X, k);
}

template <typename parent, unsigned int mode, typename T2>
arma_inline Mat<typename parent::elem_type> operator-(
    const subview_each1<parent, mode>& X, const Base<typename parent::elem_type, T2>& Y) {
  arma_debug_sigprint();

  return subview_each1_aux::operator_minus(X, Y.get_ref());
}

template <typename T1, typename parent, unsigned int mode>
arma_inline Mat<typename parent::elem_type> operator-(
    const Base<typename parent::elem_type, T1>& X, const subview_each1<parent, mode>& Y) {
  arma_debug_sigprint();

  return subview_each1_aux::operator_minus(X.get_ref(), Y);
}

template <typename parent, unsigned int mode, typename TB, typename T2>
arma_inline Mat<typename parent::elem_type> operator-(
    const subview_each2<parent, mode, TB>& X,
    const Base<typename parent::elem_type, T2>& Y) {
  arma_debug_sigprint();

  return subview_each2_aux::operator_minus(X, Y.get_ref());
}

template <typename T1, typename parent, unsigned int mode, typename TB>
arma_inline Mat<typename parent::elem_type> operator-(
    const Base<typename parent::elem_type, T1>& X,
    const subview_each2<parent, mode, TB>& Y) {
  arma_debug_sigprint();

  return subview_each2_aux::operator_minus(X.get_ref(), Y);
}

//! @}
