// SPDX-License-Identifier: BSD-2-Clause
// author: Max Kellermann <max.kellermann@gmail.com>

#include "util/IntrusiveList.hxx"
#include "util/SortList.hxx"

#include <gtest/gtest.h>

#include <string>

namespace {

template<IntrusiveHookMode mode>
struct CharItem final : IntrusiveListHook<mode> {
	char ch;

	constexpr CharItem(char _ch) noexcept:ch(_ch) {}
};

template<IntrusiveHookMode mode>
static std::string
ToString(const IntrusiveList<CharItem<mode>> &list,
	 typename IntrusiveList<CharItem<mode>>::const_iterator it,
	 std::size_t n) noexcept
{
	std::string result;
	for (std::size_t i = 0; i < n; ++i, ++it)
		result.push_back(it == list.end() ? '_' : it->ch);
	return result;
}

template<IntrusiveHookMode mode>
static std::string
ToStringReverse(const IntrusiveList<CharItem<mode>> &list,
		typename IntrusiveList<CharItem<mode>>::const_iterator it,
		std::size_t n) noexcept
{
	std::string result;
	for (std::size_t i = 0; i < n; ++i, --it)
		result.push_back(it == list.end() ? '_' : it->ch);
	return result;
}

} // anonymous namespace

TEST(IntrusiveList, Basic)
{
	using Item = CharItem<IntrusiveHookMode::NORMAL>;

	Item items[]{'a', 'b', 'c'};

	IntrusiveList<Item> list;
	for (auto &i : items)
		list.push_back(i);

	ASSERT_EQ(ToString(list, list.begin(), 5), "abc_a");
	ASSERT_EQ(ToStringReverse(list, list.begin(), 5), "a_cba");

	items[1].unlink();

	ASSERT_EQ(ToString(list, list.begin(), 4), "ac_a");
	ASSERT_EQ(ToStringReverse(list, list.begin(), 4), "a_ca");

	IntrusiveList<Item> other_list;
	Item other_items[]{'d', 'e', 'f', 'g'};
	for (auto &i : other_items)
		other_list.push_back(i);

	list.splice(std::next(list.begin()), other_list,
		    other_list.iterator_to(other_items[1]),
		    other_list.iterator_to(other_items[3]), 2);

	ASSERT_EQ(ToString(other_list, other_list.begin(), 4), "dg_d");
	ASSERT_EQ(ToStringReverse(other_list, other_list.begin(), 4), "d_gd");

	ASSERT_EQ(ToString(list, list.begin(), 6), "aefc_a");
	ASSERT_EQ(ToStringReverse(list, list.begin(), 6), "a_cfea");
}

TEST(IntrusiveList, Track)
{
	using Item = CharItem<IntrusiveHookMode::TRACK>;

	Item items[]{'a', 'b', 'c'};

	for (const auto &i : items)
		ASSERT_FALSE(i.is_linked());

	IntrusiveList<Item> list;

	list.push_back(items[1]);
	list.push_back(items[2]);
	list.push_front(items[0]);

	for (const auto &i : items)
		ASSERT_TRUE(i.is_linked());

	ASSERT_EQ(ToString(list, list.begin(), 5), "abc_a");
	ASSERT_EQ(ToStringReverse(list, list.begin(), 5), "a_cba");

	items[1].unlink();

	ASSERT_TRUE(items[0].is_linked());
	ASSERT_FALSE(items[1].is_linked());
	ASSERT_TRUE(items[2].is_linked());

	ASSERT_EQ(ToString(list, list.begin(), 4), "ac_a");
	ASSERT_EQ(ToStringReverse(list, list.begin(), 4), "a_ca");

	list.erase(list.iterator_to(items[0]));

	ASSERT_FALSE(items[0].is_linked());
	ASSERT_FALSE(items[1].is_linked());
	ASSERT_TRUE(items[2].is_linked());

	ASSERT_EQ(ToString(list, list.begin(), 3), "c_c");
	ASSERT_EQ(ToStringReverse(list, list.begin(), 3), "c_c");

	list.clear();

	ASSERT_FALSE(items[0].is_linked());
	ASSERT_FALSE(items[1].is_linked());
	ASSERT_FALSE(items[2].is_linked());

	ASSERT_EQ(ToString(list, list.begin(), 2), "__");
	ASSERT_EQ(ToStringReverse(list, list.begin(), 2), "__");

	{
		IntrusiveList<Item> list2;
		list2.push_back(items[0]);
		ASSERT_TRUE(items[0].is_linked());
	}

	ASSERT_FALSE(items[0].is_linked());
}

TEST(IntrusiveList, AutoUnlink)
{
	using Item = CharItem<IntrusiveHookMode::AUTO_UNLINK>;

	Item a{'a'};
	ASSERT_FALSE(a.is_linked());

	IntrusiveList<Item> list;

	Item b{'b'};
	ASSERT_FALSE(b.is_linked());

	{
		Item c{'c'};

		list.push_back(a);
		list.push_back(b);
		list.push_back(c);

		ASSERT_TRUE(a.is_linked());
		ASSERT_TRUE(b.is_linked());
		ASSERT_TRUE(c.is_linked());

		ASSERT_EQ(ToString(list, list.begin(), 5), "abc_a");
	}

	ASSERT_EQ(ToString(list, list.begin(), 5), "ab_ab");

	ASSERT_TRUE(a.is_linked());
	ASSERT_TRUE(b.is_linked());
}

TEST(IntrusiveList, Tag)
{
	struct A {};
	struct B {};

	struct TaggedItem
		: public IntrusiveListHook<IntrusiveHookMode::NORMAL, A>,
		  public IntrusiveListHook<IntrusiveHookMode::NORMAL, B> {};

	TaggedItem one, two;

	IntrusiveList<TaggedItem, IntrusiveListBaseHookTraits<TaggedItem, A>> a;
	IntrusiveList<TaggedItem, IntrusiveListBaseHookTraits<TaggedItem, B>> b;

	EXPECT_TRUE(a.empty());
	EXPECT_TRUE(b.empty());

	a.push_back(one);
	a.push_back(two);

	EXPECT_FALSE(a.empty());
	EXPECT_TRUE(b.empty());

	b.push_back(one);

	EXPECT_FALSE(a.empty());
	EXPECT_FALSE(b.empty());

	a.clear();

	EXPECT_TRUE(a.empty());
	EXPECT_FALSE(b.empty());

	a.push_back(two);
	a.push_back(one);

	EXPECT_FALSE(a.empty());
	EXPECT_FALSE(b.empty());

	b.erase(b.iterator_to(one));

	EXPECT_FALSE(a.empty());
	EXPECT_TRUE(b.empty());
}

TEST(IntrusiveList, Merge)
{
	using Item = CharItem<IntrusiveHookMode::NORMAL>;

	const auto predicate = [](const Item &a, const Item &b){
		return a.ch < b.ch;
	};

	Item items[]{'c', 'k', 'u'};

	IntrusiveList<Item> list;
	for (auto &i : items)
		list.push_back(i);

	IntrusiveList<Item> other_list;
	Item other_items[]{'a', 'b', 'g', 'm', 'n', 'x', 'y', 'z'};
	for (auto &i : other_items)
		other_list.push_back(i);

	MergeList(list, other_list, predicate);

	ASSERT_EQ(ToString(list, list.begin(), 13), "abcgkmnuxyz_a");
	ASSERT_TRUE(other_list.empty());

	Item more_items[]{'a', 'o', 'p', 'q'};
	for (auto &i : more_items)
		other_list.push_back(i);

	MergeList(list, other_list, predicate);

	ASSERT_EQ(ToString(list, list.begin(), 17), "aabcgkmnopquxyz_a");
	ASSERT_EQ(&*list.begin(), &other_items[0]);
	ASSERT_EQ(&*std::next(list.begin()), &more_items[0]);
}

TEST(IntrusiveList, Sort)
{
	using Item = CharItem<IntrusiveHookMode::NORMAL>;

	const auto predicate = [](const Item &a, const Item &b){
		return a.ch < b.ch;
	};

	Item items[]{'z', 'a', 'b', 'q', 'b', 'c', 't', 'm', 'y'};

	IntrusiveList<Item> list;
	SortList(list, predicate);
	ASSERT_EQ(ToString(list, list.begin(), 2), "__");

	list.push_back(items[0]);
	SortList(list, predicate);
	ASSERT_EQ(ToString(list, list.begin(), 3), "z_z");

	list.push_back(items[1]);
	SortList(list, predicate);
	ASSERT_EQ(ToString(list, list.begin(), 4), "az_a");
	SortList(list, predicate);
	ASSERT_EQ(ToString(list, list.begin(), 4), "az_a");

	list.clear();
	for (auto &i : items)
		list.push_back(i);

	SortList(list, predicate);
	ASSERT_EQ(ToString(list, list.begin(), 11), "abbcmqtyz_a");
	ASSERT_EQ(&*std::next(list.begin(), 1), &items[2]);
	ASSERT_EQ(&*std::next(list.begin(), 2), &items[4]);
}

/**
 * Call clear_and_dispose(), and let the disposer unlink the last
 * item.
 */
TEST(IntrusiveList, ClearDisposeUnlink)
{
	using Item = CharItem<IntrusiveHookMode::TRACK>;

	Item a{'a'}, b{'b'};

	bool a_disposed = false;

	EXPECT_FALSE(a.is_linked());
	EXPECT_FALSE(b.is_linked());

	IntrusiveList<Item> list;
	list.push_back(a);
	list.push_back(b);

	EXPECT_TRUE(a.is_linked());
	EXPECT_TRUE(b.is_linked());

	list.clear_and_dispose([&](Item *item){
		EXPECT_FALSE(a.is_linked());
		EXPECT_TRUE(b.is_linked());
		EXPECT_EQ(item, &a);
		EXPECT_FALSE(a_disposed);

		a_disposed = true;

		b.unlink();
	});

	EXPECT_TRUE(a_disposed);
	EXPECT_TRUE(list.empty());
}

/**
 * Call clear_and_dispose(), and let the disposer push a new item.
 */
TEST(IntrusiveList, ClearDisposePush)
{
	using Item = CharItem<IntrusiveHookMode::TRACK>;

	Item a{'a'}, b{'b'};

	bool a_disposed = false, b_added = false, b_disposed = false;

	EXPECT_FALSE(a.is_linked());
	EXPECT_FALSE(b.is_linked());

	IntrusiveList<Item> list;
	list.push_back(a);

	EXPECT_TRUE(a.is_linked());
	EXPECT_FALSE(b.is_linked());

	list.clear_and_dispose([&](Item *item){
		if (!a_disposed) {
			EXPECT_EQ(item, &a);
			EXPECT_FALSE(a.is_linked());
			EXPECT_FALSE(b.is_linked());
			EXPECT_FALSE(a_disposed);
			EXPECT_FALSE(b_disposed);
			EXPECT_FALSE(b_added);

			a_disposed = true;

			list.push_back(b);
			EXPECT_FALSE(a.is_linked());
			EXPECT_TRUE(b.is_linked());

			b_added = true;
		} else if (!b_disposed) {
			EXPECT_TRUE(b_added);
			EXPECT_EQ(item, &b);
			EXPECT_FALSE(a.is_linked());
			EXPECT_FALSE(b.is_linked());
			EXPECT_TRUE(a_disposed);
			EXPECT_FALSE(b_disposed);

			b_disposed = true;
		} else {
			FAIL();
		}
	});

	EXPECT_TRUE(a_disposed);
	EXPECT_TRUE(b_added);
	EXPECT_TRUE(b_disposed);
	EXPECT_TRUE(list.empty());
}