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

// REQUIRES: std-at-least-c++26

// ranges

// inline constexpr unspecified indices = unspecified;

// FIXME: This test shouldn't define TEST_HAS_NO_INT128
// ADDITIONAL_COMPILE_FLAGS(clang-modules-build): -fno-modules

#include <cassert>
#include <cstddef>
#include <ranges>
#include <vector>

#include "test_macros.h"
#include "type_algorithms.h"

#include "types.h"

// Test SFINAE.

template <typename SizeType>
concept HasIndices = requires(SizeType s) { std::ranges::views::indices(s); };

struct NotIntegerLike {};

void test_SFINAE() {
  static_assert(HasIndices<std::size_t>);
  types::for_each(types::integer_types(), []<typename T> { static_assert(HasIndices<T>); });

  // Non-integer-like types should not satisfy HasIndices
  static_assert(!HasIndices<bool>);
  static_assert(!HasIndices<float>);
  static_assert(!HasIndices<void>);
  static_assert(!HasIndices<SomeInt>); // Does satisfy is_integer_like, but not the conversion to std::size_t
  static_assert(!HasIndices<NotIntegerLike>);
}

constexpr bool test() {
  {
    auto indices_view = std::ranges::views::indices(5);
    static_assert(std::ranges::range<decltype(indices_view)>);

    assert(indices_view.size() == 5);

    assert(indices_view[0] == 0);
    assert(indices_view[1] == 1);
    assert(indices_view[2] == 2);
    assert(indices_view[3] == 3);
    assert(indices_view[4] == 4);
  }

  {
    std::vector v(5, 0);

    auto indices_view = std::ranges::views::indices(std::ranges::size(v));
    static_assert(std::ranges::range<decltype(indices_view)>);

    assert(indices_view.size() == 5);

    assert(indices_view[0] == 0);
    assert(indices_view[1] == 1);
    assert(indices_view[2] == 2);
    assert(indices_view[3] == 3);
    assert(indices_view[4] == 4);
  }

  {
    std::vector v(5, SomeInt{});

    auto indices_view = std::ranges::views::indices(std::ranges::size(v));
    static_assert(std::ranges::range<decltype(indices_view)>);

    assert(indices_view.size() == 5);

    assert(indices_view[0] == 0);
    assert(indices_view[1] == 1);
    assert(indices_view[2] == 2);
    assert(indices_view[3] == 3);
    assert(indices_view[4] == 4);
  }

  return true;
}

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

  return 0;
}