//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

// <forward_list>

// void splice_after(const_iterator p, forward_list&& x, const_iterator i); // constexpr since C++26

#include <forward_list>
#include <cassert>
#include <iterator>
#include <cstddef>

#include "test_macros.h"
#include "min_allocator.h"

typedef int T;
TEST_CONSTEXPR const T t1[]                 = {0, 1, 2, 3, 4, 5, 6, 7};
TEST_CONSTEXPR const T t2[]                 = {10, 11, 12};
TEST_CONSTEXPR const std::ptrdiff_t size_t1 = std::end(t1) - std::begin(t1);
TEST_CONSTEXPR const std::ptrdiff_t size_t2 = std::end(t2) - std::begin(t2);

template <class C>
TEST_CONSTEXPR_CXX26 void testd(const C& c, int p, int f) {
  typename C::const_iterator i = c.begin();
  int n1                       = 0;
  for (; n1 < p; ++n1, ++i)
    assert(*i == t1[n1]);
  for (int n2 = f; n2 < f + 1; ++n2, ++i)
    assert(*i == t2[n2]);
  for (; n1 < size_t1; ++n1, ++i)
    assert(*i == t1[n1]);
  assert(std::distance(c.begin(), c.end()) == size_t1 + 1);
}

template <class C>
TEST_CONSTEXPR_CXX26 void tests(const C& c, int p, int f) {
  typename C::const_iterator i = c.begin();
  int n                        = 0;
  if (p == f || p == f + 1) {
    for (n = 0; n < size_t1; ++n, ++i)
      assert(*i == t1[n]);
  } else if (p < f) {
    for (n = 0; n < p; ++n, ++i)
      assert(*i == t1[n]);
    for (n = f; n < f + 1; ++n, ++i)
      assert(*i == t1[n]);
    for (n = p; n < f; ++n, ++i)
      assert(*i == t1[n]);
    for (n = f + 1; n < size_t1; ++n, ++i)
      assert(*i == t1[n]);
  } else // p > f+1
  {
    for (n = 0; n < f; ++n, ++i)
      assert(*i == t1[n]);
    for (n = f + 1; n < p; ++n, ++i)
      assert(*i == t1[n]);
    for (n = f; n < f + 1; ++n, ++i)
      assert(*i == t1[n]);
    for (n = p; n < size_t1; ++n, ++i)
      assert(*i == t1[n]);
  }
  assert(std::distance(c.begin(), c.end()) == size_t1);
}

TEST_CONSTEXPR_CXX26 bool test() {
  {
    // splicing different containers
    typedef std::forward_list<T> C;
    for (int f = 0; f <= size_t2 - 1; ++f) {
      for (int p = 0; p <= size_t1; ++p) {
        C c1(std::begin(t1), std::end(t1));
        C c2(std::begin(t2), std::end(t2));

        c1.splice_after(std::next(c1.cbefore_begin(), p), std::move(c2), std::next(c2.cbefore_begin(), f));
        testd(c1, p, f);
      }
    }

    // splicing within same container
    for (int f = 0; f <= size_t1 - 1; ++f) {
      for (int p = 0; p <= size_t1; ++p) {
        C c1(std::begin(t1), std::end(t1));

        c1.splice_after(std::next(c1.cbefore_begin(), p), std::move(c1), std::next(c1.cbefore_begin(), f));
        tests(c1, p, f);
      }
    }
  }
#if TEST_STD_VER >= 11
  {
    // splicing different containers
    typedef std::forward_list<T, min_allocator<T>> C;
    for (int f = 0; f <= size_t2 - 1; ++f) {
      for (int p = 0; p <= size_t1; ++p) {
        C c1(std::begin(t1), std::end(t1));
        C c2(std::begin(t2), std::end(t2));

        c1.splice_after(std::next(c1.cbefore_begin(), p), std::move(c2), std::next(c2.cbefore_begin(), f));
        testd(c1, p, f);
      }
    }

    // splicing within same container
    for (int f = 0; f <= size_t1 - 1; ++f) {
      for (int p = 0; p <= size_t1; ++p) {
        C c1(std::begin(t1), std::end(t1));

        c1.splice_after(std::next(c1.cbefore_begin(), p), std::move(c1), std::next(c1.cbefore_begin(), f));
        tests(c1, p, f);
      }
    }
  }
#endif

  return true;
}

int main(int, char**) {
  assert(test());
#if TEST_STD_VER >= 26
  static_assert(test());
#endif

  return 0;
}
