/*!
 * \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;

   /*
    * Types to behave like Fixtures
    */
   // Test type_of fixture
   template<class T> struct Identity {
      using type = T;
   };
   template<class T1, class T2> struct MfunBin {
      using type = int;
   };
   template<int a, int b> struct MfunBin_i {
      using type = int;
   };
   template<class T1> struct MfunUn1 {
      using type = int;
   };
   template<class T1> struct MfunUn2 {
      using type = int;
   };

   template <typename T> struct Pred_isInt {
      using type = std::is_integral<T>;
   };

   template <typename T> struct Pred_isVoid {
      using type = std::is_void<T>;
   };

   /*
    * Test integral constant
    */
   TEST(Tmeta, IntegrealType) {
      EXPECT_EQ(true, (std::is_same<int, eval<Identity<int>>>::value));
   }
   TEST(Tmeta, IntegrealConstant) {
      EXPECT_EQ(true, (std::is_same<int, integral_<int, 42>::value_type>::value));
      EXPECT_EQ(true, (std::is_same<int, integral_<int, 42>::type::value_type>::value));
      EXPECT_EQ(42, (integral_<int, 0>::value_type(42)));
      EXPECT_EQ(42, (integral_<int, 42>()));
   }
   TEST(Tmeta, 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<int8_t, int8_<0>::value_type>::value));
      EXPECT_EQ(42, int8_<42>::value);
      EXPECT_EQ(true, (std::is_same<uint8_t, uint8_<0>::value_type>::value));
      EXPECT_EQ(42u, uint8_<42u>::value);
      EXPECT_EQ(true, (std::is_same<int16_t, int16_<0>::value_type>::value));
      EXPECT_EQ(42, int16_<42>::value);
      EXPECT_EQ(true, (std::is_same<uint16_t, uint16_<0>::value_type>::value));
      EXPECT_EQ(42u, uint16_<42u>::value);
      EXPECT_EQ(true, (std::is_same<int32_t, int32_<0>::value_type>::value));
      EXPECT_EQ(42, int32_<42>::value);
      EXPECT_EQ(true, (std::is_same<uint32_t, uint32_<0>::value_type>::value));
      EXPECT_EQ(42u, uint32_<42u>::value);

      EXPECT_EQ(true, (std::is_same<char, char_<0>::value_type>::value));
      EXPECT_EQ(42, char_<42>::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<long, long_<0>::value_type>::value));
      EXPECT_EQ(42, long_<42>::value);

      EXPECT_EQ(true, (std::is_same<index_t, index_<0>::value_type>::value));
      EXPECT_EQ(42U, index_<42U>::value);
      EXPECT_EQ(true, (std::is_same<size_t, size_<0>::value_type>::value));
      EXPECT_EQ(42U, size_<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, 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, 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, BitOperations) {
      EXPECT_EQ (0x00, (bitand_<uint8_<0x55>, uint8_<0xAA>>()));
      EXPECT_EQ (0xFF, (bitor_ <uint8_<0x55>, uint8_<0xAA>>()));
      EXPECT_EQ (0xFA, (bitxor_<uint8_<0x55>, uint8_<0xAF>>()));
      EXPECT_EQ (0x00, (bitnot_<uint8_<-1>>()));

      EXPECT_EQ (0x04, (shift_left<uint8_<0x01>, uint8_<2>>()));
      EXPECT_EQ (0x00, (shift_left<uint8_<0x80>, uint8_<1>>()));
      EXPECT_EQ (0x02, (shift_right<uint8_<0x08>, uint8_<2>>()));
      EXPECT_EQ (0x00, (shift_right<uint8_<0x01>, uint8_<1>>()));
   }

   TEST(Tmeta, 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<true_,  or_<true_,  false_>>()));
      EXPECT_EQ (true, (std::is_same<false_, or_<false_, false_>>()));
      EXPECT_EQ (true, (std::is_same<false_, and_<true_,  false_>>()));
      EXPECT_EQ (true, (std::is_same<true_,  and_<true_,  true_>>()));

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

   /*
    * Test void_t
    */
   TEST(Tmeta, VoidType) {
      struct Foo {};
      struct Bar {};
      EXPECT_EQ(true, (std::is_same<void, void_t<int, long, Foo, Bar>>()));
   }

   /*
    * Test invoke
    */
   TEST(Tmeta, Invoke) {
      using Q = quote<MfunBin>;
      using Qi = quote_i<int, MfunBin_i>;
      using Q1 = quote<MfunUn1>;
      using Q2 = quote<MfunUn2>;

      EXPECT_EQ (true, (std::is_same<int, identity_t<int>>()));

      EXPECT_EQ (true,  (is_applicable_t<MfunBin, int, long>()));
      EXPECT_EQ (false, (is_applicable_t<MfunBin, int>()));
      EXPECT_EQ (true,  (is_applicable_qt<Q, int, long>()));
      EXPECT_EQ (false, (is_applicable_qt<Q, int>()));

      EXPECT_EQ (true,  (is_applicable_it<int, MfunBin_i, 7, 42>()));
      EXPECT_EQ (false, (is_applicable_it<int, MfunBin_i, 42>()));

      EXPECT_EQ (true, (std::is_same<defer<MfunBin, int, void>::type, MfunBin<int, void>>()));
      EXPECT_EQ (true, (std::is_same<defer<MfunBin, void>::type, nil_>()));
      EXPECT_EQ (true, (std::is_same<defer_i<int, MfunBin_i, 7, 42>::type, MfunBin_i<7, 42>>()));
      EXPECT_EQ (true, (std::is_same<defer_i<int, MfunBin_i, 7>::type, nil_>()));

      EXPECT_EQ (true, (std::is_same<invoke<Q, int>, nil_>()));
      EXPECT_EQ (true, (std::is_same<invoke<Q, int, void*>, MfunBin<int, void*>>()));
      EXPECT_EQ (true, (std::is_same<invoke<Qi, int_<7>, int_<42>>, MfunBin_i<7, 42>>()));
      EXPECT_EQ (true, (std::is_same<invoke<Qi, int_<42>>, nil_>()));

      EXPECT_EQ (true, (std::is_same<invoke<compose<Q1, Q2>, int>, MfunUn1<MfunUn2<int>>>()));
      EXPECT_EQ (true, (std::is_same<
                           invoke<compose<Q1, Q2, Qi>, int_<7>, int_<42>>,
                           MfunUn1<MfunUn2<MfunBin_i<7, 42>>>
                        >()));
      EXPECT_EQ (true, (std::is_same<
                           invoke<compose<Q1, Q2, Qi>, int_<42>>,
                           MfunUn1<MfunUn2<nil_>>
                        >()));

      EXPECT_EQ (true, (std::is_same<invoke<bind_front<Q, int>, long>, MfunBin<int, long>>()));
      EXPECT_EQ (true, (std::is_same<invoke<bind_back<Q, int>, long>, MfunBin<long, int>>()));

   }
   /*
    * Test typelist
    */
   TEST(Tmeta_typelist, Basics) {
      using l1 = typelist<int, int, int>;
      using l2 = typelist<int, void*, int, void*>;
      using l3 = typelist<>;

      EXPECT_EQ (true, (std::is_same<l1, typelist<int>::times<3>>()));
      EXPECT_EQ (true, (std::is_same<l2, typelist<int, void*>::times<2>>()));
      EXPECT_EQ (true, (std::is_same<l3, typelist<>::times<3>>()));
      EXPECT_EQ (true, (std::is_same<l3, typelist<int>::times<0>>()));
      EXPECT_EQ (true, (std::is_same<typelist<short, double>, pair<short, double>>()));

      EXPECT_EQ (true, (std::is_same<l1, repeat <int_<3>, int>>()));
      EXPECT_EQ (true, (std::is_same<l2, repeat_c <2, int, void*>>()));


      EXPECT_EQ (3,    size<l1>());
      EXPECT_EQ (true, empty<l3>());

      // pass typelist to an invocable
      EXPECT_EQ (true, (std::is_same<eval<
                                        apply<quote<MfunBin>, typelist<int, long>>
                                     >,
                                     MfunBin<int, long>
                        >()));
   }

   TEST(Tmeta_typelist, Element_access) {
      using l = typelist<char, void, long, double, short>;

      EXPECT_EQ (true, (std::is_same<char, at_c<l, 0>>()));
      EXPECT_EQ (true, (std::is_same<long, at_c<l, 2>>()));
      EXPECT_EQ (true, (std::is_same<nil_, at_c<l, 5>>()));
      EXPECT_EQ (true, (std::is_same<void, at<l, int_<1>>>()));

      EXPECT_EQ (true, (std::is_same<char, front<l>>()));
      EXPECT_EQ (true, (std::is_same<short, back<l>>()));
   }

   TEST(Tmeta_typelist, Concat) {
      using l1 = typelist<int, long, void>;
      using l2 = typelist<void*, int*>;
      using l3 = typelist<double, long double, short>;
      using l4 = typelist<>;
      using conc = typelist<int, long, void, void*, int*, double, long double, short>;

      EXPECT_EQ(true, (std::is_same<l4, cat<l4, l4>>()));
      EXPECT_EQ(true, (std::is_same<conc, cat<l1, l2, l3, l4>>()));
      EXPECT_EQ(true, (std::is_same<conc, cat<l1, l4, l2, l3>>()));
      EXPECT_EQ(true, (std::is_same<conc, cat<l4, l1, l2, l3>>()));
   }

   template<class T1, class T2> struct F {}; // binary invocable
   TEST(Tmeta_typelist, 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, PushPopReverse) {
      using list   = typelist            <int, long, void>;
      using l_char = typelist            <int, long, void, char>;
      using l_cc   = typelist            <int, long, void, char, char>;
      using char_l = typelist      <char, int, long, void>;
      using cc_l   = typelist<char, char, int, long, void>;
      using rev    = typelist<void, long, int>;

      EXPECT_EQ (true, (std::is_same<char_l, push_front<list, char>>()));
      EXPECT_EQ (true, (std::is_same<cc_l,   push_front<list, char, char>>()));
      EXPECT_EQ (true, (std::is_same<list,   pop_front <char_l>>()));
      EXPECT_EQ (true, (std::is_same<l_char, push_back <list, char>>()));
      EXPECT_EQ (true, (std::is_same<l_cc,   push_back <list, char, char>>()));
      EXPECT_EQ (true, (std::is_same<list,   pop_back  <l_char>>()));

      EXPECT_EQ (true, (std::is_same<rev, reverse <list>>()));
   }

   TEST(Tmeta_typelist, Transform) {
      using QBin = quote<MfunBin>;
      using QUn = quote<MfunUn1>;

      using l1 = typelist<char, int, float>;
      using l2 = typelist<void, void, void>;
      using r  = typelist<int, int, int>;
      using r_ulazy = typelist <MfunUn1<char>, MfunUn1<int>, MfunUn1<float>>;
      using r_blazy = typelist <MfunBin<char, void>, MfunBin<int, void>, MfunBin<float, void>>;

      EXPECT_EQ (true, (std::is_same<r, transform<l1, QUn>>()));
      EXPECT_EQ (true, (std::is_same<r, transform<l1, l2, QBin>>()));

      EXPECT_EQ (true, (std::is_same<r_ulazy, transform_lazy<l1, QUn>>()));
      EXPECT_EQ (true, (std::is_same<r_blazy, transform_lazy<l1, l2, QBin>>()));
   }


   TEST(Tmeta_typelist, Find) {
      using l1 = typelist <int, char, long, float>;
      using l2 = typelist <char, long, float>;
      using l3 = typelist <long, float>;
      using empty = typelist<>;

      EXPECT_EQ(true, (std::is_same<index_<1>, find_if<l1, same_as<char>>>()));
      EXPECT_EQ(true, (std::is_same<Npos, find_if<empty, same_as<char>>>()));
      EXPECT_EQ(true, (std::is_same<Npos, find_if<l1, same_as<double>>>()));

      EXPECT_EQ(true, (std::is_same<index_<2>, find<l1, long>>()));

      EXPECT_EQ(true, (std::is_same<l2, seek_if<l1, same_as<char>>>()));
      EXPECT_EQ(true, (std::is_same<empty, seek_if<empty, same_as<char>>>()));
      EXPECT_EQ(true, (std::is_same<empty, seek_if<l1, same_as<double>>>()));

      EXPECT_EQ(true, (std::is_same<l3, seek<l1, long>>()));
   }

   TEST(Tmeta_typelist, Count) {
      using list = typelist<int, void*, char, int, long*, char, int, short>;
      using empty = typelist<>;

      EXPECT_EQ (true, (std::is_same<size_<3>, count_if<list, same_as<int>>>()));
      EXPECT_EQ (true, (std::is_same<size_<2>, count_if<list, same_as<char>>>()));
      EXPECT_EQ (true, (std::is_same<size_<0>, count_if<list, same_as<double>>>()));
      EXPECT_EQ (true, (std::is_same<size_<0>, count_if<empty, int>>()));

      EXPECT_EQ (true, (std::is_same<size_<1>, count<list, void*>>()));
   }

   TEST(Tmeta_typelist, Filter) {
      using Q1 = quote<Pred_isInt>;
      using Q2 = quote<Pred_isVoid>;
      using list     = typelist<int, float, char, long*, short, double, void*>;
      using filtered = typelist<int, char, short>;

      EXPECT_EQ (true, (std::is_same<filtered,   filter<list, Q1>>()));
      EXPECT_EQ (true, (std::is_same<typelist<>, filter<typelist<>, Q1>>()));
      EXPECT_EQ (true, (std::is_same<typelist<>, filter<list, Q2>>()));
   }

   TEST(Tmeta_typelist, Replace) {
      using Q = quote<Pred_isInt>;
      using list = typelist<int, float, char, long*, short, double, void*>;
      using res  = typelist<void,float, void, long*, void,  double, void*>;
      using repl = typelist<int, float, void, long*, short, double, void*>;

      EXPECT_EQ (true, (std::is_same<res, replace_if<list, Q, void>>()));
      EXPECT_EQ (true, (std::is_same<typelist<>, replace_if<typelist<>, Q, void>>()));
      EXPECT_EQ (true, (std::is_same<res, replace_if<res, Q, void>>()));

      EXPECT_EQ (true, (std::is_same<repl, replace<list, char, void>>()));
   }

   TEST (Tmeta_typelist, AllAnyNone) {
      using l1 = typelist<int, float, char, long*, short, double, void*>;
      using l2 = typelist<int, char, long, short>;

      EXPECT_EQ (true, (std::is_same<false_, all_of<l1, quote<Pred_isInt>>>()));
      EXPECT_EQ (true, (std::is_same<true_,  all_of<l2, quote<Pred_isInt>>>()));

      EXPECT_EQ (true, (std::is_same<true_,  any_of<l1, quote<Pred_isInt>>>()));
      EXPECT_EQ (true, (std::is_same<false_, any_of<l2, quote<Pred_isVoid>>>()));

      EXPECT_EQ (true, (std::is_same<true_,  none_of<l1, quote<Pred_isVoid>>>()));
      EXPECT_EQ (true, (std::is_same<false_, none_of<l1, quote<Pred_isInt>>>()));
   }

}