/*!
 * \file Tmeta.cpp
 *
 * Copyright (C) 2018 Christos Choutouridis
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
#include <utl/meta/meta.h>
#include <gtest/gtest.h>
#include <type_traits>

namespace test_meta {
   using namespace utl;
   using namespace meta;

   /*
    * Test integral constant
    */
   // Test type_of fixture
   template<class T> struct TestTypeOf {
      using type = T;
   };
   TEST(Tmeta_integral, Integreal_type_) {
      EXPECT_EQ(true, (std::is_same<int, type_<TestTypeOf<int>>>::value));
   }
   TEST(Tmeta_integral, IntegrealConstant) {
      EXPECT_EQ(true, (std::is_same<int, integral_constant<int, 42>::value_type>::value));
      EXPECT_EQ(true, (std::is_same<int, integral_constant<int, 42>::type::value_type>::value));
      EXPECT_EQ(42, (integral_constant<int, 0>::value_type(42)));
      EXPECT_EQ(42, (integral_constant<int, 42>()));
   }
   TEST(Tmeta_integral, BasicTypes) {
      EXPECT_EQ(true, (std::is_same<bool, bool_<false>::value_type>::value));
      EXPECT_EQ(true, bool_<true>::value);
      EXPECT_EQ(true, (std::is_same<bool, false_::value_type>::value));
      EXPECT_EQ(false, false_::value);
      EXPECT_EQ(true, (std::is_same<bool, true_::value_type>::value));
      EXPECT_EQ(true, true_::value);
      EXPECT_EQ(true, (std::is_same<int, int_<0>::value_type>::value));
      EXPECT_EQ(42, int_<42>::value);

      EXPECT_EQ(true, (std::is_same<index_t, index_t_<0>::value_type>::value));
      EXPECT_EQ(42U, index_t_<42U>::value);
      EXPECT_EQ(true, (std::is_same<size_t, size_t_<0>::value_type>::value));
      EXPECT_EQ(42U, size_t_<42U>::value);

      EXPECT_EQ(sizeof(int), sizeof_<int>::value);
      EXPECT_EQ(alignof(int), alignof_<int>::value);
      EXPECT_EQ(static_cast<index_t>(-1), Npos::value);
   }
   /*
    * Test integral constant arithmetic operations
    */
   TEST(Tmeta_integral, ArithmeticOperations) {
      EXPECT_EQ (int_<42>(), inc<int_<41>>());
      EXPECT_EQ (int_<42>(), dec<int_<43>>());
      EXPECT_EQ (int_<42>(), (add<int_<23>, add<int_<17>, int_<2>>>()));
      EXPECT_EQ (int_<42>(), (sub<int_<108>, int_<66>>()));
      EXPECT_EQ (int_<42>(), (mult<int_<7>, mult<int_<3>, int_<2>>>()));
      EXPECT_EQ (int_<42>(), (divide<int_<210>, int_<5>>()));
      EXPECT_EQ (int_<42>(), negate<int_<-42>>());
      EXPECT_EQ (int_< 1>(), (modulo<int_<43>, int_<42>>()));
   }

   /*
    * Test logical
    */
   TEST(Tmeta_logical, ComparisonOperations) {
      EXPECT_EQ (true, (std::is_same<bool_<true>, not_c<false>>::value));
      EXPECT_EQ (true, (comp_eq<int_<7>, int_<7>>()));
      EXPECT_EQ (true, (comp_ne<int_<42>, int_<7>>()));
      EXPECT_EQ (true, (comp_lt<int_<42>, int_<43>>()));
      EXPECT_EQ (true, (comp_gt<int_<43>, int_<42>>()));
      EXPECT_EQ (true, (comp_le<int_<42>, int_<42>>()));
      EXPECT_EQ (true, (comp_ge<int_<42>, int_<42>>()));
   }

   TEST(Tmeta_logical, BitOperations) {
      EXPECT_EQ (0x00, (bitand_<int_<0x55>, int_<0xAA>>()));
      EXPECT_EQ (0xFF, (bitor_<int_<0x55>, int_<0xAA>>()));
      EXPECT_EQ (0xFA, (bitxor_<int_<0x55>, int_<0xAF>>()));
      EXPECT_EQ (0x00, (bitnot_<int_<-1>>()));
      //XXX: add shifts
   }

   TEST(Tmeta_logical, TypeOperations) {
      struct Foo {};
      struct Bar {};

      EXPECT_EQ (true, (std::is_same<bool_<true>, not_<bool_<false>>>()));
      EXPECT_EQ (true, (std::is_same<int_<42>, if_c<true, int_<42>, bool_<false>>>()));
      EXPECT_EQ (true, (std::is_same<int_<42>, if_<bool_<true>, int_<42>, bool_<false>>>()));

      EXPECT_EQ (true, (std::is_same<bool_<true>,  or_<bool_<true>,  bool_<false>>>()));
      EXPECT_EQ (true, (std::is_same<bool_<false>, or_<bool_<false>, bool_<false>>>()));
      EXPECT_EQ (true, (std::is_same<bool_<false>, and_<bool_<true>,  bool_<false>>>()));
      EXPECT_EQ (true, (std::is_same<bool_<true>,  and_<bool_<true>,  bool_<true>>>()));

      EXPECT_EQ (true, (same_<Foo, Foo>()));
      EXPECT_EQ (false, (same_<Foo, Bar>()));
      EXPECT_EQ (true, (not_same_<Foo, Bar>()));
   }

   /*
    * Test void
    */
   TEST(Tmeta_void, VoidType) {
      struct Foo {};
      struct Bar {};
      EXPECT_EQ(true, (std::is_same<void, void_t<int, long, Foo, Bar>>()));
   }
   /*
    * Test invoke
    */
   template<class T1, class T2> struct MetaFunction { using type = int; };
   template<typename... Args>   struct MetaClass {using apply = int; };
   TEST(Tmeta_invoke, Invoke) {
      //EXPECT_EQ (true, (is_evaluable<MetaFunction, int .long>()));
   }
   /*
    * Test typelist
    */
   template<class T1, class T2> struct F {};
   TEST(Tmeta_typelist, List_fold) {
      struct X1 {};
      struct X2 {};
      struct X3 {};
      struct X4 {};
      using Q = quote<F>;

      EXPECT_EQ(true, (std::is_same<fold<typelist<>, void, Q>, void>()));
      EXPECT_EQ(true, (std::is_same<fold<typelist<X1>, void, Q>, F<void, X1>>()));
      EXPECT_EQ(true, (std::is_same<fold<typelist<X1, X2>, void, Q>, F<F<void, X1>, X2>>()));
      EXPECT_EQ(true, (std::is_same<fold<typelist<X1, X2, X3>, void, Q>, F<F<F<void, X1>, X2>, X3>>()));
      EXPECT_EQ(true, (std::is_same<fold<typelist<X1, X2, X3, X4>, void, Q>, F<F<F<F<void, X1>, X2>, X3>, X4>>()));

      //EXPECT_EQ(true, (std::is_same<rev_fold<typelist<>, void, Q>, void>()));
      EXPECT_EQ(true, (std::is_same<rev_fold<typelist<X1>, void, Q>, F<X1, void>>()));
      EXPECT_EQ(true, (std::is_same<rev_fold<typelist<X1, X2>, void, Q>, F<X1, F<X2, void>>>()));
      EXPECT_EQ(true, (std::is_same<rev_fold<typelist<X1, X2, X3>, void, Q>, F<X1, F<X2, F<X3, void>>>>()));
      EXPECT_EQ(true, (std::is_same<rev_fold<typelist<X1, X2, X3, X4>, void, Q>, F<X1, F<X2, F<X3, F<X4, void>>>>>()));
   }
   TEST(Tmeta_typelist, ListOperations) {
      using l1 = typelist<int, short, long>;
      using l2 = typelist<>;
      using l3 = typelist<float, double, long double>;
      using l4 = typelist<void*, char*>;
      using conc = typelist<int, short, long, float, double, long double, void*, char*>;
      using rep = typelist<int, int, int>;

      EXPECT_EQ(3, size<l1>());
      EXPECT_EQ(true, empty<l2>());

      EXPECT_EQ(true, (std::is_same<conc, concat<l1, l2, l3, l4>>()));
      EXPECT_EQ(true, (std::is_same<rep, repeat_n<int_<3>, int>>()));
      EXPECT_EQ(true, (std::is_same<int, front<l1>>()));
      EXPECT_EQ(true, (std::is_same<long, back<l1>>()));
      EXPECT_EQ(true, (std::is_same<double, at<l3, int_<1>>>()));

      EXPECT_EQ(true, (std::is_same<typelist<short, long>, pop_front<l1>>()));
   }
}