//     __ _____ _____ _____
//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
// |  |  |__   |  |  | | | |  version 3.11.3
// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
//
// SPDX-FileCopyrightText: 2013-2023 Niels Lohmann <https://nlohmann.me>
// SPDX-License-Identifier: MIT

#include "doctest_compatibility.h"

#define _azure_JSON_TESTS_PRIVATE
#include <azure/core/internal/json/json.hpp>
using Azure::Core::Json::_internal::json;

namespace {
// special test case to check if memory is leaked if constructor throws
template <class T> struct bad_allocator : std::allocator<T>
{
  using std::allocator<T>::allocator;

  bad_allocator() = default;
  template <class U> bad_allocator(const bad_allocator<U>& /*unused*/) {}

  template <class... Args>
  void construct(
      T* /*unused*/,
      Args&&... /*unused*/) // NOLINT(cppcoreguidelines-missing-std-forward)
  {
    throw std::bad_alloc();
  }

  template <class U> struct rebind
  {
    using other = bad_allocator<U>;
  };
};
} // namespace

TEST_CASE("bad_alloc")
{
  SECTION("bad_alloc")
  {
    // create JSON type using the throwing allocator
    using bad_json = Azure::Core::Json::_internal::basic_json<
        std::map,
        std::vector,
        std::string,
        bool,
        std::int64_t,
        std::uint64_t,
        double,
        bad_allocator>;

    // creating an object should throw
    CHECK_THROWS_AS(bad_json(bad_json::value_t::object), std::bad_alloc&);
  }
}

namespace {
bool next_construct_fails = false;
bool next_destroy_fails = false;
bool next_deallocate_fails = false;

template <class T> struct my_allocator : std::allocator<T>
{
  using std::allocator<T>::allocator;

  template <class... Args> void construct(T* p, Args&&... args)
  {
    if (next_construct_fails)
    {
      next_construct_fails = false;
      throw std::bad_alloc();
    }

    ::new (reinterpret_cast<void*>(p)) T(std::forward<Args>(args)...);
  }

  void deallocate(T* p, std::size_t n)
  {
    if (next_deallocate_fails)
    {
      next_deallocate_fails = false;
      throw std::bad_alloc();
    }

    std::allocator<T>::deallocate(p, n);
  }

  void destroy(T* p)
  {
    if (next_destroy_fails)
    {
      next_destroy_fails = false;
      throw std::bad_alloc();
    }

    static_cast<void>(p); // fix MSVC's C4100 warning
    p->~T();
  }

  template <class U> struct rebind
  {
    using other = my_allocator<U>;
  };
};

// allows deletion of raw pointer, usually hold by json_value
template <class T> void my_allocator_clean_up(T* p)
{
  assert(p != nullptr);
  my_allocator<T> alloc;
  alloc.destroy(p);
  alloc.deallocate(p, 1);
}
} // namespace

TEST_CASE("controlled bad_alloc")
{
  // create JSON type using the throwing allocator
  using my_json = Azure::Core::Json::_internal::basic_json<
      std::map,
      std::vector,
      std::string,
      bool,
      std::int64_t,
      std::uint64_t,
      double,
      my_allocator>;

  SECTION("class json_value")
  {
    SECTION("json_value(value_t)")
    {
      SECTION("object")
      {
        next_construct_fails = false;
        auto t = my_json::value_t::object;
        CHECK_NOTHROW(my_allocator_clean_up(my_json::json_value(t).object));
        next_construct_fails = true;
        CHECK_THROWS_AS(my_json::json_value(t), std::bad_alloc&);
        next_construct_fails = false;
      }
      SECTION("array")
      {
        next_construct_fails = false;
        auto t = my_json::value_t::array;
        CHECK_NOTHROW(my_allocator_clean_up(my_json::json_value(t).array));
        next_construct_fails = true;
        CHECK_THROWS_AS(my_json::json_value(t), std::bad_alloc&);
        next_construct_fails = false;
      }
      SECTION("string")
      {
        next_construct_fails = false;
        auto t = my_json::value_t::string;
        CHECK_NOTHROW(my_allocator_clean_up(my_json::json_value(t).string));
        next_construct_fails = true;
        CHECK_THROWS_AS(my_json::json_value(t), std::bad_alloc&);
        next_construct_fails = false;
      }
    }

    SECTION("json_value(const string_t&)")
    {
      next_construct_fails = false;
      const my_json::string_t v("foo");
      CHECK_NOTHROW(my_allocator_clean_up(my_json::json_value(v).string));
      next_construct_fails = true;
      CHECK_THROWS_AS(my_json::json_value(v), std::bad_alloc&);
      next_construct_fails = false;
    }
  }

  SECTION("class basic_json")
  {
    SECTION("basic_json(const CompatibleObjectType&)")
    {
      next_construct_fails = false;
      const std::map<std::string, std::string> v{{"foo", "bar"}};
      CHECK_NOTHROW(my_json(v));
      next_construct_fails = true;
      CHECK_THROWS_AS(my_json(v), std::bad_alloc&);
      next_construct_fails = false;
    }

    SECTION("basic_json(const CompatibleArrayType&)")
    {
      next_construct_fails = false;
      const std::vector<std::string> v{"foo", "bar", "baz"};
      CHECK_NOTHROW(my_json(v));
      next_construct_fails = true;
      CHECK_THROWS_AS(my_json(v), std::bad_alloc&);
      next_construct_fails = false;
    }

    SECTION("basic_json(const typename string_t::value_type*)")
    {
      next_construct_fails = false;
      CHECK_NOTHROW(my_json("foo"));
      next_construct_fails = true;
      CHECK_THROWS_AS(my_json("foo"), std::bad_alloc&);
      next_construct_fails = false;
    }

    SECTION("basic_json(const typename string_t::value_type*)")
    {
      next_construct_fails = false;
      const std::string s("foo");
      CHECK_NOTHROW(my_json(s));
      next_construct_fails = true;
      CHECK_THROWS_AS(my_json(s), std::bad_alloc&);
      next_construct_fails = false;
    }
  }
}

namespace {
template <class T> struct allocator_no_forward : std::allocator<T>
{
  allocator_no_forward() = default;
  template <class U> allocator_no_forward(allocator_no_forward<U> /*unused*/) {}

  template <class U> struct rebind
  {
    using other = allocator_no_forward<U>;
  };

  template <class... Args>
  void construct(T* p, const Args&... args) noexcept(noexcept(::new (static_cast<void*>(p))
                                                                  T(args...)))
  {
    // force copy even if move is available
    ::new (static_cast<void*>(p)) T(args...);
  }
};
} // namespace

TEST_CASE("bad my_allocator::construct")
{
  SECTION("my_allocator::construct doesn't forward")
  {
    using bad_alloc_json = Azure::Core::Json::_internal::basic_json<
        std::map,
        std::vector,
        std::string,
        bool,
        std::int64_t,
        std::uint64_t,
        double,
        allocator_no_forward>;

    bad_alloc_json j;
    j["test"] = bad_alloc_json::array_t();
    j["test"].push_back("should not leak");
  }
}
