/* Copyright (C) 2016 Murray Cumming
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/
 */

#include <cassert>
#include <cstdlib>
#include <sigc++/tuple-utils/tuple_for_each.h>
#include <iostream>
#include <functional>
#include <string>

template<typename T_element_from>
class for_each_simple
{
public:
  static void visit(const T_element_from& from)
  {
    std::cout << "for_each_simple(): " << std::to_string(from) << std::endl;
  }
};

void
test_tuple_for_each_same_types()
{
  {
    auto t_original = std::make_tuple(1, 2, 3);
    sigc::internal::tuple_for_each<for_each_simple>(t_original);
  }

  {
    auto t_original = std::make_tuple(1, static_cast<double>(2.1f), 3);
    sigc::internal::tuple_for_each<for_each_simple>(t_original);
  }
}

template<typename T_element_from>
class for_each_simple_with_extras
{
public:
  static void visit(const T_element_from& from, int extra1, const std::string& extra2)
  {
    std::cout << "for_each_simple_with_extras(): from=" << std::to_string(from)
              << ", extra1: " << extra1 << ", extra2: " << extra2 << std::endl;
  }
};

void
test_tuple_for_each_same_types_with_extras()
{
  {
    auto t_original = std::make_tuple(1, static_cast<double>(2.1f), 3);
    sigc::internal::tuple_for_each<for_each_simple_with_extras>(t_original, 89, "eightynine");
  }
}

template<typename T_element_from>
class for_each_simple_with_nonconst_extras
{
public:
  static void visit(const T_element_from& from, int& extra) { extra += (int)from; }
};

void
test_tuple_for_each_same_types_with_nonconst_extras()
{
  {
    auto t_original = std::make_tuple(1, static_cast<double>(2.1f), 3);
    int extra = 0;

    sigc::internal::tuple_for_each<for_each_simple_with_nonconst_extras>(t_original, extra);
    // std::cout << "extra: " << extra << std::endl;
    assert(extra == 6);
  }
}

// The general template declaration.
// We then provide specializations for each type,
// so we can test having a different return value for each T_element_from type.
template<typename T_element_from>
class visitor_with_specializations;

// An int will be converted to a std::string:
template<>
class visitor_with_specializations<int>
{
public:
  static void visit(const int& from)
  {
    std::cout << "visitor_with_specializations::visit(): " << std::to_string(from) << std::endl;
  }
};

// A double will be converted to a char:
template<>
class visitor_with_specializations<double>
{
public:
  static void visit(const double& from)
  {
    std::cout << "visitor_with_specializations::visit(): " << std::to_string(from)[0] << std::endl;
  }
};

// A std::string will be converted to an int:
template<>
class visitor_with_specializations<std::string>
{
public:
  static void visit(const std::string& from)
  {
    std::cout << "visitor_with_specializations::visit(): " << std::stoi(from) << std::endl;
  }
};

// A const char* will be converted to an int:
template<>
class visitor_with_specializations<const char*>
{
public:
  static void visit(const char* from)
  {
    std::cout << "visitor_with_specializations::visit(): " << std::stoi(from) << std::endl;
  }
};

void
test_tuple_for_each_multiple_types()
{
  auto t_original = std::make_tuple(1, static_cast<double>(2.1f), std::string("3"));
  sigc::internal::tuple_for_each<visitor_with_specializations>(t_original);
}

template<typename T_element_from>
class for_each_nonconst
{
public:
  static void visit(T_element_from& from)
  {
    from *= 2;
    // Or, for instance, call a non-const method on from.
  }
};

void
test_tuple_for_each_nonconst()
{
  auto t = std::make_tuple(1, 2, 3);
  sigc::internal::tuple_for_each<for_each_nonconst, decltype(t)&>(t);
  std::cout << std::get<0>(t) << std::endl;
  assert(std::get<0>(t) == 2);
  assert(std::get<1>(t) == 4);
  assert(std::get<2>(t) == 6);
}

void
test_tuple_for_each_stdref()
{
  {
    int a = 1;
    int b = 2;
    int c = 3;
    auto t_original = std::make_tuple(std::ref(a), std::ref(b), std::ref(c));
    sigc::internal::tuple_for_each<for_each_simple>(t_original);
  }

  {
    int a = 1;
    int b = 2;
    int c = 3;
    auto t_original = std::make_tuple(std::ref(a), std::ref(b), std::ref(c));
    sigc::internal::tuple_for_each<for_each_nonconst>(t_original);
    assert(a == 2);
    assert(b == 4);
    assert(c == 6);
  }
}

static std::string correct_sequence_output;

template<typename T_element_from>
class for_each_correct_sequence
{
public:
  static void visit(const T_element_from& from)
  {
    // std::cout << "from: " << from << std::endl;
    correct_sequence_output += std::to_string(from);
  }
};

void
test_tuple_for_each_correct_sequence()
{
  correct_sequence_output.clear();
  auto t = std::make_tuple(1, 2, 3);
  sigc::internal::tuple_for_each<for_each_correct_sequence>(t);
  // std::cout << "correct_sequence_output: " << correct_sequence_output << std::endl;
  assert(correct_sequence_output == "123");
}

void
test_tuple_for_each_empty_tuple()
{
  auto t = std::tuple<>();
  sigc::internal::tuple_for_each<for_each_simple>(t);
}

constexpr void
test_tuple_for_each_constexpr()
{
  constexpr auto t_original = std::make_tuple(1, static_cast<double>(2.1f), "3");
  sigc::internal::tuple_for_each<visitor_with_specializations>(t_original);
}

int
main()
{
  test_tuple_for_each_same_types();
  test_tuple_for_each_same_types_with_extras();
  test_tuple_for_each_same_types_with_nonconst_extras();

  test_tuple_for_each_multiple_types();

  test_tuple_for_each_nonconst();

  test_tuple_for_each_stdref();

  test_tuple_for_each_correct_sequence();

  test_tuple_for_each_empty_tuple();

  test_tuple_for_each_constexpr();

  return EXIT_SUCCESS;
}