//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <algorithm>

// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20

// template<input_iterator I, sentinel_for<I> S, class T, class Proj = identity>
//     requires indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T*>
//     constexpr bool ranges::contains(I first, S last, const T& value, Proj proj = {});       // since C++23

// template<input_range R, class T, class Proj = identity>
//     requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<R>, Proj>, const T*>
//     constexpr bool ranges::contains(R&& r, const T& value, Proj proj = {});                 // since C++23

#include <algorithm>
#include <cassert>
#include <list>
#include <ranges>
#include <string>
#include <vector>

#include "almost_satisfies_types.h"
#include "boolean_testable.h"
#include "test_iterators.h"

struct NotEqualityComparable {};

template <class Iter, class Sent = Iter>
concept HasContainsIt = requires(Iter iter, Sent sent) { std::ranges::contains(iter, sent, *iter); };

static_assert(HasContainsIt<int*>);
static_assert(HasContainsIt<int*, int*>);
static_assert(!HasContainsIt<NotEqualityComparable*>);
static_assert(!HasContainsIt<InputIteratorNotDerivedFrom>);
static_assert(!HasContainsIt<InputIteratorNotIndirectlyReadable>);
static_assert(!HasContainsIt<InputIteratorNotInputOrOutputIterator>);
static_assert(!HasContainsIt<cpp20_input_iterator<int*>, SentinelForNotSemiregular>);
static_assert(!HasContainsIt<cpp20_input_iterator<int*>, InputRangeNotSentinelEqualityComparableWith>);
static_assert(!HasContainsIt<cpp20_input_iterator<int*>, sentinel_wrapper<cpp20_input_iterator<int*>>>);

static_assert(!HasContainsIt<int*, int>);
static_assert(!HasContainsIt<int, int*>);

template <class Range, class ValT>
concept HasContainsR = requires(Range&& range) { std::ranges::contains(std::forward<Range>(range), ValT{}); };

static_assert(!HasContainsR<int, int>);
static_assert(HasContainsR<int[1], int>);
static_assert(!HasContainsR<NotEqualityComparable[1], NotEqualityComparable>);
static_assert(!HasContainsR<InputRangeNotDerivedFrom, int>);
static_assert(!HasContainsR<InputRangeNotIndirectlyReadable, int>);
static_assert(!HasContainsR<InputRangeNotInputOrOutputIterator, int>);
static_assert(!HasContainsR<InputRangeNotSentinelSemiregular, int>);
static_assert(!HasContainsR<InputRangeNotSentinelEqualityComparableWith, int>);

template <class Iter, class Sent = Iter>
constexpr void test_iterators() {
  using ValueT = std::iter_value_t<Iter>;
  { // simple tests
    ValueT a[] = {1, 2, 3, 4, 5, 6};
    auto whole = std::ranges::subrange(Iter(a), Sent(Iter(a + 6)));
    {
      std::same_as<bool> decltype(auto) ret = std::ranges::contains(whole.begin(), whole.end(), 3);
      assert(ret);
    }
    {
      std::same_as<bool> decltype(auto) ret = std::ranges::contains(whole, 3);
      assert(ret);
    }
  }

  { // check that a range with a single element works
    ValueT a[] = {32};
    auto whole = std::ranges::subrange(Iter(a), Sent(Iter(a + 1)));
    {
      bool ret = std::ranges::contains(whole.begin(), whole.end(), 32);
      assert(ret);
    }
    {
      bool ret = std::ranges::contains(whole, 32);
      assert(ret);
    }
  }

  { // check that an empty range works
    ValueT a[] = {};
    auto whole = std::ranges::subrange(Iter(a), Sent(Iter(a)));
    {
      bool ret = std::ranges::contains(whole.begin(), whole.end(), 1);
      assert(!ret);
    }
    {
      bool ret = std::ranges::contains(whole, 1);
      assert(!ret);
    }
  }

  { // check that the first element matches
    ValueT a[] = {32, 3, 2, 1, 0, 23, 21, 9, 40, 100};
    auto whole = std::ranges::subrange(Iter(a), Sent(Iter(a + 10)));
    {
      bool ret = std::ranges::contains(whole.begin(), whole.end(), 32);
      assert(ret);
    }
    {
      bool ret = std::ranges::contains(whole, 32);
      assert(ret);
    }
  }

  { // check that the last element matches
    ValueT a[] = {3, 22, 1, 43, 99, 0, 56, 100, 32};
    auto whole = std::ranges::subrange(Iter(a), Sent(Iter(a + 9)));
    {
      bool ret = std::ranges::contains(whole.begin(), whole.end(), 32);
      assert(ret);
    }
    {
      bool ret = std::ranges::contains(whole, 32);
      assert(ret);
    }
  }

  { // no match
    ValueT a[] = {13, 1, 21, 4, 5};
    auto whole = std::ranges::subrange(Iter(a), Sent(Iter(a + 5)));
    {
      bool ret = std::ranges::contains(whole.begin(), whole.end(), 10);
      assert(!ret);
    }
    {
      bool ret = std::ranges::contains(whole, 10);
      assert(!ret);
    }
  }

  { // check that the projections are used
    int a[] = {1, 9, 0, 13, 25};
    {
      bool ret = std::ranges::contains(a, a + 5, -13, [&](int i) { return i * -1; });
      assert(ret);
    }
    {
      auto range = std::ranges::subrange(a, a + 5);
      bool ret   = std::ranges::contains(range, -13, [&](int i) { return i * -1; });
      assert(ret);
    }
  }
}

constexpr bool test() {
  types::for_each(types::type_list<char, long long>{}, []<class T> {
    types::for_each(types::cpp20_input_iterator_list<T*>{}, []<class Iter> {
      if constexpr (std::forward_iterator<Iter>)
        test_iterators<Iter>();
      test_iterators<Iter, sentinel_wrapper<Iter>>();
      test_iterators<Iter, sized_sentinel<Iter>>();
    });
  });

  { // count invocations of the projection for continuous iterators
    int a[]              = {1, 9, 0, 13, 25};
    int projection_count = 0;
    {
      bool ret = std::ranges::contains(a, a + 5, 0, [&](int i) {
        ++projection_count;
        return i;
      });
      assert(ret);
      assert(projection_count == 3);
      projection_count = 0;
    }
    {
      bool ret = std::ranges::contains(a, 0, [&](int i) {
        ++projection_count;
        return i;
      });
      assert(ret);
      assert(projection_count == 3);
    }
  }

  { // check invocations of the projection for std::string
    const std::string str{"hello world"};
    const std::string str1{"hi world"};
    int projection_count = 0;
    {
      std::string a[] = {str1, str1, str, str1, str1};
      auto whole =
          std::ranges::subrange(forward_iterator(std::move_iterator(a)), forward_iterator(std::move_iterator(a + 5)));
      bool ret = std::ranges::contains(whole.begin(), whole.end(), "hello world", [&](const std::string i) {
        ++projection_count;
        return i;
      });
      assert(ret);
      assert(projection_count == 3);
      projection_count = 0;
    }
    {
      std::string a[] = {str1, str1, str, str1, str1};
      auto whole =
          std::ranges::subrange(forward_iterator(std::move_iterator(a)), forward_iterator(std::move_iterator(a + 5)));
      bool ret = std::ranges::contains(whole, "hello world", [&](const std::string i) {
        ++projection_count;
        return i;
      });
      assert(ret);
      assert(projection_count == 3);
    }
  }

  { // check invocations of the projection for non-continuous iterators
    std::vector<bool> whole{false, false, true, false};
    int projection_count = 0;
    {
      bool ret = std::ranges::contains(whole.begin(), whole.end(), true, [&](int i) {
        ++projection_count;
        return i;
      });
      assert(ret);
      assert(projection_count == 3);
      projection_count = 0;
    }
    {
      bool ret = std::ranges::contains(whole, true, [&](int i) {
        ++projection_count;
        return i;
      });
      assert(ret);
      assert(projection_count == 3);
    }
  }

  { // check invocations of the projection for views::transform
    int a[]              = {1, 2, 3, 4, 5};
    int projection_count = 0;
    auto square_number   = a | std::views::transform([](int x) { return x * x; });
    {
      bool ret = std::ranges::contains(square_number.begin(), square_number.end(), 16, [&](int i) {
        ++projection_count;
        return i;
      });
      assert(ret);
      assert(projection_count == 4);
      projection_count = 0;
    }
    {
      bool ret = std::ranges::contains(square_number, 16, [&](int i) {
        ++projection_count;
        return i;
      });
      assert(ret);
      assert(projection_count == 4);
    }
  }

  return true;
}

// test for non-contiguous containers
bool test_nonconstexpr() {
  std::list<int> a     = {7, 5, 0, 16, 8};
  int projection_count = 0;
  {
    bool ret = std::ranges::contains(a.begin(), a.end(), 0, [&](int i) {
      ++projection_count;
      return i;
    });
    assert(ret);
    assert(projection_count == 3);
    projection_count = 0;
  }
  {
    bool ret = std::ranges::contains(a, 0, [&](int i) {
      ++projection_count;
      return i;
    });
    assert(ret);
    assert(projection_count == 3);
  }

  return true;
}

int main(int, char**) {
  test();
  static_assert(test());

  assert(test_nonconstexpr());

  return 0;
}
