// 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_inv_gen
//! @{

class op_inv_gen_default : public traits_op_default {
 public:
  template <typename T1>
  inline static void apply(Mat<typename T1::elem_type>& out,
                           const Op<T1, op_inv_gen_default>& in);

  template <typename T1>
  inline static bool apply_direct(Mat<typename T1::elem_type>& out,
                                  const Base<typename T1::elem_type, T1>& expr,
                                  const char* caller_sig);
};

class op_inv_gen_full : public traits_op_default {
 public:
  template <const uword row, const uword col>
  struct pos {
    static constexpr uword n2 = row + col * 2;
    static constexpr uword n3 = row + col * 3;
  };

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

  template <typename T1, const bool has_user_flags = true>
  inline static bool apply_direct(Mat<typename T1::elem_type>& out,
                                  const Base<typename T1::elem_type, T1>& expr,
                                  const char* caller_sig, const uword flags);

  template <typename eT>
  arma_cold inline static bool apply_tiny_2x2(Mat<eT>& X);

  template <typename eT>
  arma_cold inline static bool apply_tiny_3x3(Mat<eT>& X);
};

template <typename T>
struct op_inv_gen_state {
  uword size = uword(0);
  T rcond = T(0);
  bool is_diag = false;
  bool is_sym = false;
};

class op_inv_gen_rcond : public traits_op_default {
 public:
  template <typename T1>
  inline static bool apply_direct(Mat<typename T1::elem_type>& out_inv,
                                  op_inv_gen_state<typename T1::pod_type>& out_state,
                                  const Base<typename T1::elem_type, T1>& expr);
};

namespace inv_opts {
struct opts {
  const uword flags;

  inline constexpr explicit opts(const uword in_flags);

  inline const opts operator+(const opts& rhs) const;
};

inline constexpr opts::opts(const uword in_flags) : flags(in_flags) {}

inline const opts opts::operator+(const opts& rhs) const {
  const opts result(flags | rhs.flags);

  return result;
}

// The values below (eg. 1u << 1) are for internal Armadillo use only.
// The values can change without notice.

static constexpr uword flag_none = uword(0);
static constexpr uword flag_fast = uword(1u << 0);
static constexpr uword flag_tiny = uword(1u << 0);  // deprecated
static constexpr uword flag_allow_approx = uword(1u << 1);
static constexpr uword flag_likely_sympd = uword(1u << 2);  // deprecated
static constexpr uword flag_no_sympd = uword(1u << 3);      // deprecated
static constexpr uword flag_no_ugly = uword(1u << 4);

struct opts_none : public opts {
  inline constexpr opts_none() : opts(flag_none) {}
};
struct opts_fast : public opts {
  inline constexpr opts_fast() : opts(flag_fast) {}
};
struct opts_tiny : public opts {
  inline constexpr opts_tiny() : opts(flag_tiny) {}
};
struct opts_allow_approx : public opts {
  inline constexpr opts_allow_approx() : opts(flag_allow_approx) {}
};
struct opts_likely_sympd : public opts {
  inline constexpr opts_likely_sympd() : opts(flag_likely_sympd) {}
};
struct opts_no_sympd : public opts {
  inline constexpr opts_no_sympd() : opts(flag_no_sympd) {}
};
struct opts_no_ugly : public opts {
  inline constexpr opts_no_ugly() : opts(flag_no_ugly) {}
};

static constexpr opts_none none;
static constexpr opts_fast fast;
static constexpr opts_tiny tiny;
static constexpr opts_allow_approx allow_approx;
static constexpr opts_likely_sympd likely_sympd;
static constexpr opts_no_sympd no_sympd;
static constexpr opts_no_ugly no_ugly;
}  // namespace inv_opts

//! @}
