//
// CRLib - Simple library for STL replacement in private projects.
// Copyright © 2020 YaPB Development Team <team@yapb.ru>.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// 

#pragma once

#include <crlib/cr-basic.h>
#include <crlib/cr-movable.h>

CR_NAMESPACE_BEGIN

// simple pair (twin)
template <typename A, typename B> class Twin final {
public:
   A first;
   B second;

public:
   template <typename T, typename U> Twin (T &&a, U &&b) : first (cr::forward <T> (a)), second (cr::forward <U> (b)) { }
   template <typename T, typename U> Twin (const Twin <T, U> &rhs) : first (rhs.first), second (rhs.second) { }
   template <typename T, typename U> Twin (Twin <T, U> &&rhs) noexcept : first (cr::move (rhs.first)), second (cr::move (rhs.second)) { }

public:
   explicit Twin () = default;
   ~Twin () = default;

public:
   template <typename T, typename U> Twin &operator = (const Twin <T, U> &rhs) {
      first = rhs.first;
      second = rhs.second;

      return *this;
   }

   template <typename T, typename U> Twin &operator = (Twin <T, U> &&rhs) {
      first = cr::move (rhs.first);
      second = cr::move (rhs.second);

      return *this;
   }

   // specialized operators for binary heap, do not use as it's test only second element
public:
   friend bool operator < (const Twin &a, const Twin &b) {
      return a.second < b.second;
   }

   friend bool operator > (const Twin &a, const Twin &b) {
      return b.second < a.second;
   }
};

CR_NAMESPACE_END