// Copyright 2014 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include <limits>
#include <memory>
#include <tuple>
#include <type_traits>
#include <unordered_set>

#include <gtest/gtest.h>  // NOLINT

#include "Common/Common.h"
#include "Common/MathUtil.h"
#include "VideoCommon/CPMemory.h"
#include "VideoCommon/DataReader.h"
#include "VideoCommon/OpcodeDecoding.h"
#include "VideoCommon/VertexLoaderBase.h"
#include "VideoCommon/VertexLoaderManager.h"

TEST(VertexLoaderUID, UniqueEnough)
{
	std::unordered_set<VertexLoaderUID> uids;

	TVtxDesc vtx_desc;
	memset(&vtx_desc, 0, sizeof(vtx_desc));
	VAT vat;
	memset(&vat, 0, sizeof(vat));
	uids.insert(VertexLoaderUID(vtx_desc, vat));

	vtx_desc.Hex = 0xFEDCBA9876543210ull;
	EXPECT_EQ(uids.end(), uids.find(VertexLoaderUID(vtx_desc, vat)));
	uids.insert(VertexLoaderUID(vtx_desc, vat));

	vat.g0.Hex = 0xFFFFFFFF;
	vat.g1.Hex = 0xFFFFFFFF;
	vat.g2.Hex = 0xFFFFFFFF;
	EXPECT_EQ(uids.end(), uids.find(VertexLoaderUID(vtx_desc, vat)));
	uids.insert(VertexLoaderUID(vtx_desc, vat));
}

static u8 input_memory[16 * 1024 * 1024];
static u8 output_memory[16 * 1024 * 1024];

class VertexLoaderTest : public testing::Test
{
protected:

	void SetUp() override
	{
		memset(input_memory, 0, sizeof(input_memory));
		memset(output_memory, 0xFF, sizeof(input_memory));

		memset(&m_vtx_desc, 0, sizeof(m_vtx_desc));
		memset(&m_vtx_attr, 0, sizeof(m_vtx_attr));

		m_loader = nullptr;

		ResetPointers();
	}

	void CreateAndCheckSizes(size_t input_size, size_t output_size)
	{
		m_loader = VertexLoaderBase::CreateVertexLoader(m_vtx_desc, m_vtx_attr);
		ASSERT_EQ((int)input_size, m_loader->m_VertexSize);
		ASSERT_EQ((int)output_size, m_loader->m_native_vtx_decl.stride);
	}

	template <typename T>
	void Input(T val)
	{
		// Write swapped.
		m_src.Write<T, true>(val);
	}

	void ExpectOut(float val)
	{
		// Read unswapped.
		MathUtil::IntFloat expected(val), actual(m_dst.Read<float, false>());
		if (!actual.f || actual.f != actual.f)
			EXPECT_EQ(expected.i, actual.i);
		else
			EXPECT_EQ(expected.f, actual.f);
	}

	void RunVertices(int count, int expected_count = -1)
	{
		if (expected_count == -1)
			expected_count = count;
		ResetPointers();
		int actual_count = m_loader->RunVertices(m_src, m_dst, count);
		EXPECT_EQ(actual_count, expected_count);
	}

	void ResetPointers()
	{
		m_src = DataReader(input_memory, input_memory + sizeof(input_memory));
		m_dst = DataReader(output_memory, output_memory + sizeof(output_memory));
	}

	DataReader m_src;
	DataReader m_dst;

	TVtxDesc m_vtx_desc;
	VAT m_vtx_attr;
	std::unique_ptr<VertexLoaderBase> m_loader;
};

class VertexLoaderParamTest : public VertexLoaderTest, public ::testing::WithParamInterface<std::tuple<int, int, int, int>> {};
extern int gtest_AllCombinationsVertexLoaderParamTest_dummy_;
INSTANTIATE_TEST_CASE_P(
	AllCombinations, VertexLoaderParamTest,
	::testing::Combine(
		::testing::Values(DIRECT, INDEX8, INDEX16),
		::testing::Values(FORMAT_UBYTE, FORMAT_BYTE, FORMAT_USHORT, FORMAT_SHORT, FORMAT_FLOAT),
		::testing::Values(0, 1), // elements
		::testing::Values(0, 1, 31) // frac
	)
);

TEST_P(VertexLoaderParamTest, PositionAll)
{
	int addr, format, elements, frac;
	std::tie(addr, format, elements, frac) = GetParam();
	this->m_vtx_desc.Position = addr;
	this->m_vtx_attr.g0.PosFormat = format;
	this->m_vtx_attr.g0.PosElements = elements;
	this->m_vtx_attr.g0.PosFrac = frac;
	this->m_vtx_attr.g0.ByteDequant = true;
	elements += 2;

	std::vector<float> values = {
		std::numeric_limits<float>::lowest(),
		std::numeric_limits<float>::denorm_min(),
		std::numeric_limits<float>::min(),
		std::numeric_limits<float>::max(),
		std::numeric_limits<float>::quiet_NaN(),
		std::numeric_limits<float>::infinity(),
		-0x8000, -0x80, -1, -0, 0, 1, 123, 0x7F, 0xFF, 0x7FFF, 0xFFFF, 12345678,
	};
	ASSERT_EQ(0u, values.size() % 2);
	ASSERT_EQ(0u, values.size() % 3);

	int count = (int)values.size() / elements;
	u32 elem_size = 1 << (format / 2);
	size_t input_size = elements * elem_size;
	if (addr & MASK_INDEXED)
	{
		input_size = addr - 1;
		for (int i = 0; i < count; i++)
			if (addr == INDEX8)
				Input<u8>(i);
			else
				Input<u16>(i);
		VertexLoaderManager::cached_arraybases[ARRAY_POSITION] = m_src.GetPointer();
		g_main_cp_state.array_strides[ARRAY_POSITION] = elements * elem_size;
	}
	CreateAndCheckSizes(input_size, elements * sizeof(float));
	for (float value : values)
	{
		switch (format)
		{
		case FORMAT_UBYTE:  Input((u8)value);  break;
		case FORMAT_BYTE:   Input((s8)value);  break;
		case FORMAT_USHORT: Input((u16)value); break;
		case FORMAT_SHORT:  Input((s16)value); break;
		case FORMAT_FLOAT:  Input(value);      break;
		}
	}

	RunVertices(count);

	float scale = 1.f / (1u << (format == FORMAT_FLOAT ? 0 : frac));
	for (auto iter = values.begin(); iter != values.end();)
	{
		float f, g;
		switch (format)
		{
		case FORMAT_UBYTE:  f = (u8)*iter++;  g = (u8)*iter++;  break;
		case FORMAT_BYTE:   f = (s8)*iter++;  g = (s8)*iter++;  break;
		case FORMAT_USHORT: f = (u16)*iter++; g = (u16)*iter++; break;
		case FORMAT_SHORT:  f = (s16)*iter++; g = (s16)*iter++; break;
		case FORMAT_FLOAT:  f = *iter++;      g = *iter++;      break;
		}
		ExpectOut(f * scale);
		ExpectOut(g * scale);
	}
}

TEST_F(VertexLoaderTest, PositionIndex16FloatXY)
{
	m_vtx_desc.Position = INDEX16;
	m_vtx_attr.g0.PosFormat = FORMAT_FLOAT;
	CreateAndCheckSizes(sizeof(u16), 2 * sizeof(float));
	Input<u16>(1); Input<u16>(0);
	VertexLoaderManager::cached_arraybases[ARRAY_POSITION] = m_src.GetPointer();
	g_main_cp_state.array_strides[ARRAY_POSITION] = sizeof(float); // ;)
	Input(1.f); Input(2.f); Input(3.f);
	RunVertices(2);
	ExpectOut(2); ExpectOut(3);
	ExpectOut(1); ExpectOut(2);
}

class VertexLoaderSpeedTest : public VertexLoaderTest, public ::testing::WithParamInterface<std::tuple<int, int>> {};
extern int gtest_FormatsAndElementsVertexLoaderSpeedTest_dummy_;
INSTANTIATE_TEST_CASE_P(
	FormatsAndElements, VertexLoaderSpeedTest,
	::testing::Combine(
		::testing::Values(FORMAT_UBYTE, FORMAT_BYTE, FORMAT_USHORT, FORMAT_SHORT, FORMAT_FLOAT),
		::testing::Values(0, 1) // elements
	)
);

TEST_P(VertexLoaderSpeedTest, PositionDirectAll)
{
	int format, elements;
	std::tie(format, elements) = GetParam();
	const char* map[] = { "u8", "s8", "u16", "s16", "float" };
	printf("format: %s, elements: %d\n", map[format], elements);
	m_vtx_desc.Position = DIRECT;
	m_vtx_attr.g0.PosFormat = format;
	m_vtx_attr.g0.PosElements = elements;
	elements += 2;
	size_t elem_size = static_cast<size_t>(1) << (format / 2);
	CreateAndCheckSizes(elements * elem_size, elements * sizeof(float));
	for (int i = 0; i < 1000; ++i)
		RunVertices(100000);
}

TEST_P(VertexLoaderSpeedTest, TexCoordSingleElement)
{
	int format, elements;
	std::tie(format, elements) = GetParam();
	const char* map[] = { "u8", "s8", "u16", "s16", "float" };
	printf("format: %s, elements: %d\n", map[format], elements);
	m_vtx_desc.Position = DIRECT;
	m_vtx_attr.g0.PosFormat = FORMAT_BYTE;
	m_vtx_desc.Tex0Coord = DIRECT;
	m_vtx_attr.g0.Tex0CoordFormat = format;
	m_vtx_attr.g0.Tex0CoordElements = elements;
	elements += 1;
	size_t elem_size = static_cast<size_t>(1) << (format / 2);
	CreateAndCheckSizes(2 * sizeof(s8)    + elements * elem_size,
	                    2 * sizeof(float) + elements * sizeof(float));
	for (int i = 0; i < 1000; ++i)
		RunVertices(100000);
}

TEST_F(VertexLoaderTest, LargeFloatVertexSpeed)
{
	// Enables most attributes in floating point indexed mode to test speed.
	m_vtx_desc.PosMatIdx = 1;
	m_vtx_desc.Tex0MatIdx = 1;
	m_vtx_desc.Tex1MatIdx = 1;
	m_vtx_desc.Tex2MatIdx = 1;
	m_vtx_desc.Tex3MatIdx = 1;
	m_vtx_desc.Tex4MatIdx = 1;
	m_vtx_desc.Tex5MatIdx = 1;
	m_vtx_desc.Tex6MatIdx = 1;
	m_vtx_desc.Tex7MatIdx = 1;
	m_vtx_desc.Position = INDEX16;
	m_vtx_desc.Normal = INDEX16;
	m_vtx_desc.Color0 = INDEX16;
	m_vtx_desc.Color1 = INDEX16;
	m_vtx_desc.Tex0Coord = INDEX16;
	m_vtx_desc.Tex1Coord = INDEX16;
	m_vtx_desc.Tex2Coord = INDEX16;
	m_vtx_desc.Tex3Coord = INDEX16;
	m_vtx_desc.Tex4Coord = INDEX16;
	m_vtx_desc.Tex5Coord = INDEX16;
	m_vtx_desc.Tex6Coord = INDEX16;
	m_vtx_desc.Tex7Coord = INDEX16;

	m_vtx_attr.g0.PosElements = 1;        // XYZ
	m_vtx_attr.g0.PosFormat = FORMAT_FLOAT;
	m_vtx_attr.g0.NormalElements = 1;     // NBT
	m_vtx_attr.g0.NormalFormat = FORMAT_FLOAT;
	m_vtx_attr.g0.Color0Elements = 1;     // Has Alpha
	m_vtx_attr.g0.Color0Comp = FORMAT_32B_8888;
	m_vtx_attr.g0.Color1Elements = 1;     // Has Alpha
	m_vtx_attr.g0.Color1Comp = FORMAT_32B_8888;
	m_vtx_attr.g0.Tex0CoordElements = 1;  // ST
	m_vtx_attr.g0.Tex0CoordFormat = FORMAT_FLOAT;
	m_vtx_attr.g1.Tex1CoordElements = 1;  // ST
	m_vtx_attr.g1.Tex1CoordFormat = FORMAT_FLOAT;
	m_vtx_attr.g1.Tex2CoordElements = 1;  // ST
	m_vtx_attr.g1.Tex2CoordFormat = FORMAT_FLOAT;
	m_vtx_attr.g1.Tex3CoordElements = 1;  // ST
	m_vtx_attr.g1.Tex3CoordFormat = FORMAT_FLOAT;
	m_vtx_attr.g1.Tex4CoordElements = 1;  // ST
	m_vtx_attr.g1.Tex4CoordFormat = FORMAT_FLOAT;
	m_vtx_attr.g2.Tex5CoordElements = 1;  // ST
	m_vtx_attr.g2.Tex5CoordFormat = FORMAT_FLOAT;
	m_vtx_attr.g2.Tex6CoordElements = 1;  // ST
	m_vtx_attr.g2.Tex6CoordFormat = FORMAT_FLOAT;
	m_vtx_attr.g2.Tex7CoordElements = 1;  // ST
	m_vtx_attr.g2.Tex7CoordFormat = FORMAT_FLOAT;

	CreateAndCheckSizes(33, 156);

	for (int i = 0; i < 12; i++)
	{
		VertexLoaderManager::cached_arraybases[i] = m_src.GetPointer();
		g_main_cp_state.array_strides[i] = 129;
	}

	// This test is only done 100x in a row since it's ~20x slower using the
	// current vertex loader implementation.
	for (int i = 0; i < 100; ++i)
		RunVertices(100000);
}
