#include <gtest/gtest.h>

#include <XCEngine/Components/CameraComponent.h>
#include <XCEngine/Components/GameObject.h>
#include <XCEngine/Components/MeshFilterComponent.h>
#include <XCEngine/Components/MeshRendererComponent.h>
#include <XCEngine/Core/Asset/IResource.h>
#include <XCEngine/Core/Math/Color.h>
#include <XCEngine/Core/Math/Quaternion.h>
#include <XCEngine/Core/Math/Vector2.h>
#include <XCEngine/Core/Math/Vector3.h>
#include <XCEngine/Debug/ConsoleLogSink.h>
#include <XCEngine/Debug/Logger.h>
#include <XCEngine/Rendering/RenderContext.h>
#include <XCEngine/Rendering/RenderSurface.h>
#include <XCEngine/Rendering/SceneRenderer.h>
#include <XCEngine/Resources/Material/Material.h>
#include <XCEngine/Resources/Mesh/Mesh.h>
#include <XCEngine/Resources/Texture/Texture.h>
#include <XCEngine/RHI/RHITexture.h>
#include <XCEngine/Scene/Scene.h>

#include "../../../RHI/integration/fixtures/RHIIntegrationFixture.h"

#include <memory>
#include <vector>

using namespace XCEngine::Components;
using namespace XCEngine::Debug;
using namespace XCEngine::Math;
using namespace XCEngine::Rendering;
using namespace XCEngine::Resources;
using namespace XCEngine::RHI;
using namespace XCEngine::RHI::Integration;

namespace {

constexpr const char* kD3D12Screenshot = "offscreen_scene_d3d12.ppm";
constexpr const char* kOpenGLScreenshot = "offscreen_scene_opengl.ppm";
constexpr const char* kVulkanScreenshot = "offscreen_scene_vulkan.ppm";
constexpr uint32_t kFrameWidth = 1280;
constexpr uint32_t kFrameHeight = 720;

Mesh* CreateQuadMesh() {
    auto* mesh = new Mesh();
    IResource::ConstructParams params = {};
    params.name = "OffscreenQuad";
    params.path = "Tests/Rendering/OffscreenQuad.mesh";
    params.guid = ResourceGUID::Generate(params.path);
    mesh->Initialize(params);

    StaticMeshVertex vertices[4] = {};
    vertices[0].position = Vector3(-1.0f, -1.0f, 0.0f);
    vertices[0].uv0 = Vector2(0.0f, 1.0f);
    vertices[1].position = Vector3(-1.0f, 1.0f, 0.0f);
    vertices[1].uv0 = Vector2(0.0f, 0.0f);
    vertices[2].position = Vector3(1.0f, -1.0f, 0.0f);
    vertices[2].uv0 = Vector2(1.0f, 1.0f);
    vertices[3].position = Vector3(1.0f, 1.0f, 0.0f);
    vertices[3].uv0 = Vector2(1.0f, 0.0f);

    const uint32_t indices[6] = { 0, 1, 2, 2, 1, 3 };
    mesh->SetVertexData(
        vertices,
        sizeof(vertices),
        4,
        sizeof(StaticMeshVertex),
        VertexAttribute::Position | VertexAttribute::UV0);
    mesh->SetIndexData(indices, sizeof(indices), 6, true);

    MeshSection section = {};
    section.baseVertex = 0;
    section.vertexCount = 4;
    section.startIndex = 0;
    section.indexCount = 6;
    section.materialID = 0;
    mesh->AddSection(section);
    return mesh;
}

Texture* CreateSolidTexture(const char* name, const char* path, const unsigned char rgba[4]) {
    auto* texture = new Texture();
    IResource::ConstructParams params = {};
    params.name = name;
    params.path = path;
    params.guid = ResourceGUID::Generate(params.path);
    texture->Initialize(params);
    texture->Create(
        1,
        1,
        1,
        1,
        XCEngine::Resources::TextureType::Texture2D,
        XCEngine::Resources::TextureFormat::RGBA8_UNORM,
        rgba,
        4);
    return texture;
}

Material* CreateMaterial(
    const char* name,
    const char* path,
    Texture* texture,
    MaterialRenderQueue renderQueue,
    const MaterialRenderState& renderState) {
    auto* material = new Material();
    IResource::ConstructParams params = {};
    params.name = name;
    params.path = path;
    params.guid = ResourceGUID::Generate(params.path);
    material->Initialize(params);
    material->SetTexture("_BaseColorTexture", ResourceHandle<Texture>(texture));
    material->SetRenderQueue(renderQueue);
    material->SetRenderState(renderState);
    return material;
}

GameObject* CreateQuadObject(
    Scene& scene,
    const char* name,
    Mesh* mesh,
    Material* material,
    const Vector3& position,
    const Vector3& scale,
    const Quaternion& rotation = Quaternion::Identity()) {
    GameObject* gameObject = scene.CreateGameObject(name);
    gameObject->GetTransform()->SetLocalPosition(position);
    gameObject->GetTransform()->SetLocalScale(scale);
    gameObject->GetTransform()->SetLocalRotation(rotation);

    auto* meshFilter = gameObject->AddComponent<MeshFilterComponent>();
    auto* meshRenderer = gameObject->AddComponent<MeshRendererComponent>();
    meshFilter->SetMesh(ResourceHandle<Mesh>(mesh));
    meshRenderer->SetMaterial(0, ResourceHandle<Material>(material));
    return gameObject;
}

const char* GetScreenshotFilename(RHIType backendType) {
    switch (backendType) {
        case RHIType::D3D12:
            return kD3D12Screenshot;
        case RHIType::Vulkan:
            return kVulkanScreenshot;
        case RHIType::OpenGL:
        default:
            return kOpenGLScreenshot;
    }
}

int GetComparisonThreshold(RHIType backendType) {
    (void)backendType;
    return 0;
}

class OffscreenSceneTest : public RHIIntegrationFixture {
protected:
    void SetUp() override;
    void TearDown() override;
    void RenderFrame() override;
    bool RequiresSwapChainAcquire() const override { return false; }

private:
    void BuildScene();
    RHIResourceView* GetCurrentBackBufferView();

    std::unique_ptr<Scene> mScene;
    std::unique_ptr<SceneRenderer> mSceneRenderer;
    std::vector<RHIResourceView*> mBackBufferViews;
    std::vector<Texture*> mTextures;
    std::vector<Material*> mMaterials;
    RHITexture* mOffscreenColorTexture = nullptr;
    RHIResourceView* mOffscreenColorView = nullptr;
    RHITexture* mOffscreenDepthTexture = nullptr;
    RHIResourceView* mOffscreenDepthView = nullptr;
    Mesh* mMesh = nullptr;
    ResourceStates mBackBufferState = ResourceStates::Present;
};

void OffscreenSceneTest::SetUp() {
    RHIIntegrationFixture::SetUp();

    mSceneRenderer = std::make_unique<SceneRenderer>();
    mScene = std::make_unique<Scene>("OffscreenScene");
    mMesh = CreateQuadMesh();

    BuildScene();

    TextureDesc colorDesc = {};
    colorDesc.width = kFrameWidth;
    colorDesc.height = kFrameHeight;
    colorDesc.depth = 1;
    colorDesc.mipLevels = 1;
    colorDesc.arraySize = 1;
    colorDesc.format = static_cast<uint32_t>(Format::R8G8B8A8_UNorm);
    colorDesc.textureType = static_cast<uint32_t>(XCEngine::RHI::TextureType::Texture2D);
    colorDesc.sampleCount = 1;
    colorDesc.sampleQuality = 0;
    colorDesc.flags = 0;
    mOffscreenColorTexture = GetDevice()->CreateTexture(colorDesc);
    ASSERT_NE(mOffscreenColorTexture, nullptr);

    ResourceViewDesc colorViewDesc = {};
    colorViewDesc.format = static_cast<uint32_t>(Format::R8G8B8A8_UNorm);
    colorViewDesc.dimension = ResourceViewDimension::Texture2D;
    colorViewDesc.mipLevel = 0;
    mOffscreenColorView = GetDevice()->CreateRenderTargetView(mOffscreenColorTexture, colorViewDesc);
    ASSERT_NE(mOffscreenColorView, nullptr);

    TextureDesc depthDesc = {};
    depthDesc.width = kFrameWidth;
    depthDesc.height = kFrameHeight;
    depthDesc.depth = 1;
    depthDesc.mipLevels = 1;
    depthDesc.arraySize = 1;
    depthDesc.format = static_cast<uint32_t>(Format::D24_UNorm_S8_UInt);
    depthDesc.textureType = static_cast<uint32_t>(XCEngine::RHI::TextureType::Texture2D);
    depthDesc.sampleCount = 1;
    depthDesc.sampleQuality = 0;
    depthDesc.flags = 0;
    mOffscreenDepthTexture = GetDevice()->CreateTexture(depthDesc);
    ASSERT_NE(mOffscreenDepthTexture, nullptr);

    ResourceViewDesc depthViewDesc = {};
    depthViewDesc.format = static_cast<uint32_t>(Format::D24_UNorm_S8_UInt);
    depthViewDesc.dimension = ResourceViewDimension::Texture2D;
    depthViewDesc.mipLevel = 0;
    mOffscreenDepthView = GetDevice()->CreateDepthStencilView(mOffscreenDepthTexture, depthViewDesc);
    ASSERT_NE(mOffscreenDepthView, nullptr);

    mBackBufferViews.resize(2, nullptr);
    mBackBufferState = ResourceStates::Present;
}

void OffscreenSceneTest::TearDown() {
    mSceneRenderer.reset();

    if (mOffscreenDepthView != nullptr) {
        mOffscreenDepthView->Shutdown();
        delete mOffscreenDepthView;
        mOffscreenDepthView = nullptr;
    }

    if (mOffscreenDepthTexture != nullptr) {
        mOffscreenDepthTexture->Shutdown();
        delete mOffscreenDepthTexture;
        mOffscreenDepthTexture = nullptr;
    }

    if (mOffscreenColorView != nullptr) {
        mOffscreenColorView->Shutdown();
        delete mOffscreenColorView;
        mOffscreenColorView = nullptr;
    }

    if (mOffscreenColorTexture != nullptr) {
        mOffscreenColorTexture->Shutdown();
        delete mOffscreenColorTexture;
        mOffscreenColorTexture = nullptr;
    }

    for (RHIResourceView*& backBufferView : mBackBufferViews) {
        if (backBufferView != nullptr) {
            backBufferView->Shutdown();
            delete backBufferView;
            backBufferView = nullptr;
        }
    }
    mBackBufferViews.clear();

    mScene.reset();

    for (Material* material : mMaterials) {
        delete material;
    }
    mMaterials.clear();

    for (Texture* texture : mTextures) {
        delete texture;
    }
    mTextures.clear();

    delete mMesh;
    mMesh = nullptr;

    RHIIntegrationFixture::TearDown();
}

void OffscreenSceneTest::BuildScene() {
    ASSERT_NE(mScene, nullptr);
    ASSERT_NE(mMesh, nullptr);

    GameObject* cameraObject = mScene->CreateGameObject("MainCamera");
    auto* camera = cameraObject->AddComponent<CameraComponent>();
    camera->SetPrimary(true);
    camera->SetProjectionType(CameraProjectionType::Orthographic);
    camera->SetOrthographicSize(2.0f);
    camera->SetNearClipPlane(0.1f);
    camera->SetFarClipPlane(10.0f);
    camera->SetClearColor(XCEngine::Math::Color(0.03f, 0.05f, 0.08f, 1.0f));

    const unsigned char bluePixel[4] = { 70, 110, 224, 255 };
    const unsigned char whitePixel[4] = { 244, 244, 232, 255 };
    const unsigned char redPixel[4] = { 240, 90, 90, 160 };
    const unsigned char greenPixel[4] = { 88, 236, 140, 160 };

    Texture* backgroundTexture = CreateSolidTexture(
        "BackgroundTexture",
        "Tests/Rendering/Offscreen/background.texture",
        bluePixel);
    Texture* centerTexture = CreateSolidTexture(
        "CenterTexture",
        "Tests/Rendering/Offscreen/center.texture",
        whitePixel);
    Texture* farTransparentTexture = CreateSolidTexture(
        "FarTransparentTexture",
        "Tests/Rendering/Offscreen/far.texture",
        redPixel);
    Texture* nearTransparentTexture = CreateSolidTexture(
        "NearTransparentTexture",
        "Tests/Rendering/Offscreen/near.texture",
        greenPixel);
    mTextures = {
        backgroundTexture,
        centerTexture,
        farTransparentTexture,
        nearTransparentTexture
    };

    MaterialRenderState opaqueState = {};
    opaqueState.depthTestEnable = true;
    opaqueState.depthWriteEnable = true;
    opaqueState.depthFunc = MaterialComparisonFunc::LessEqual;
    opaqueState.cullMode = MaterialCullMode::None;

    MaterialRenderState transparentState = {};
    transparentState.blendEnable = true;
    transparentState.srcBlend = MaterialBlendFactor::SrcAlpha;
    transparentState.dstBlend = MaterialBlendFactor::InvSrcAlpha;
    transparentState.srcBlendAlpha = MaterialBlendFactor::One;
    transparentState.dstBlendAlpha = MaterialBlendFactor::Zero;
    transparentState.depthTestEnable = true;
    transparentState.depthWriteEnable = false;
    transparentState.depthFunc = MaterialComparisonFunc::LessEqual;
    transparentState.cullMode = MaterialCullMode::None;

    Material* backgroundMaterial = CreateMaterial(
        "BackgroundMaterial",
        "Tests/Rendering/Offscreen/background.mat",
        backgroundTexture,
        MaterialRenderQueue::Geometry,
        opaqueState);
    Material* centerMaterial = CreateMaterial(
        "CenterMaterial",
        "Tests/Rendering/Offscreen/center.mat",
        centerTexture,
        MaterialRenderQueue::Geometry,
        opaqueState);
    Material* farTransparentMaterial = CreateMaterial(
        "FarTransparentMaterial",
        "Tests/Rendering/Offscreen/far.mat",
        farTransparentTexture,
        MaterialRenderQueue::Transparent,
        transparentState);
    Material* nearTransparentMaterial = CreateMaterial(
        "NearTransparentMaterial",
        "Tests/Rendering/Offscreen/near.mat",
        nearTransparentTexture,
        MaterialRenderQueue::Transparent,
        transparentState);
    mMaterials = {
        backgroundMaterial,
        centerMaterial,
        farTransparentMaterial,
        nearTransparentMaterial
    };

    CreateQuadObject(
        *mScene,
        "Background",
        mMesh,
        backgroundMaterial,
        Vector3(0.0f, 0.0f, 4.0f),
        Vector3(2.9f, 1.85f, 1.0f));

    CreateQuadObject(
        *mScene,
        "CenterOpaque",
        mMesh,
        centerMaterial,
        Vector3(0.0f, 0.0f, 3.0f),
        Vector3(0.42f, 1.18f, 1.0f));

    CreateQuadObject(
        *mScene,
        "FarTransparent",
        mMesh,
        farTransparentMaterial,
        Vector3(-0.18f, 0.0f, 3.45f),
        Vector3(1.02f, 1.02f, 1.0f),
        Quaternion::FromAxisAngle(Vector3::Up(), 0.56f));

    CreateQuadObject(
        *mScene,
        "NearTransparent",
        mMesh,
        nearTransparentMaterial,
        Vector3(0.18f, 0.0f, 2.65f),
        Vector3(1.02f, 1.02f, 1.0f),
        Quaternion::FromAxisAngle(Vector3::Up(), -0.56f));
}

RHIResourceView* OffscreenSceneTest::GetCurrentBackBufferView() {
    const int backBufferIndex = GetCurrentBackBufferIndex();
    if (backBufferIndex < 0) {
        return nullptr;
    }

    if (static_cast<size_t>(backBufferIndex) >= mBackBufferViews.size()) {
        mBackBufferViews.resize(static_cast<size_t>(backBufferIndex) + 1, nullptr);
    }

    if (mBackBufferViews[backBufferIndex] == nullptr) {
        ResourceViewDesc viewDesc = {};
        viewDesc.format = static_cast<uint32_t>(Format::R8G8B8A8_UNorm);
        viewDesc.dimension = ResourceViewDimension::Texture2D;
        viewDesc.mipLevel = 0;
        mBackBufferViews[backBufferIndex] = GetDevice()->CreateRenderTargetView(GetCurrentBackBuffer(), viewDesc);
    }

    return mBackBufferViews[backBufferIndex];
}

void OffscreenSceneTest::RenderFrame() {
    ASSERT_NE(mScene, nullptr);
    ASSERT_NE(mSceneRenderer, nullptr);
    ASSERT_NE(mOffscreenColorView, nullptr);
    ASSERT_NE(mOffscreenDepthView, nullptr);

    RHICommandList* commandList = GetCommandList();
    ASSERT_NE(commandList, nullptr);

    RHIResourceView* backBufferView = GetCurrentBackBufferView();
    ASSERT_NE(backBufferView, nullptr);

    commandList->Reset();

    RenderSurface offscreenSurface(kFrameWidth, kFrameHeight);
    offscreenSurface.SetColorAttachment(mOffscreenColorView);
    offscreenSurface.SetDepthAttachment(mOffscreenDepthView);
    offscreenSurface.SetColorStateBefore(ResourceStates::Common);
    offscreenSurface.SetColorStateAfter(ResourceStates::CopySrc);

    RenderContext renderContext = {};
    renderContext.device = GetDevice();
    renderContext.commandList = commandList;
    renderContext.commandQueue = GetCommandQueue();
    renderContext.backendType = GetBackendType();

    ASSERT_TRUE(mSceneRenderer->Render(*mScene, nullptr, renderContext, offscreenSurface));

    commandList->TransitionBarrier(backBufferView, mBackBufferState, ResourceStates::CopyDst);
    commandList->CopyResource(backBufferView, mOffscreenColorView);
    commandList->TransitionBarrier(mOffscreenColorView, ResourceStates::CopySrc, ResourceStates::Common);
    commandList->TransitionBarrier(backBufferView, ResourceStates::CopyDst, ResourceStates::RenderTarget);
    mBackBufferState = ResourceStates::RenderTarget;

    commandList->Close();
    void* commandLists[] = { commandList };
    GetCommandQueue()->ExecuteCommandLists(1, commandLists);
}

TEST_P(OffscreenSceneTest, RenderOffscreenScene) {
    RHICommandQueue* commandQueue = GetCommandQueue();
    const int targetFrameCount = 30;
    const char* screenshotFilename = GetScreenshotFilename(GetBackendType());
    const int comparisonThreshold = GetComparisonThreshold(GetBackendType());

    for (int frameCount = 0; frameCount <= targetFrameCount; ++frameCount) {
        if (frameCount > 0) {
            commandQueue->WaitForPreviousFrame();
        }

        BeginRender();
        RenderFrame();

        if (frameCount >= targetFrameCount) {
            commandQueue->WaitForIdle();
            ASSERT_TRUE(TakeScreenshot(screenshotFilename));
            ASSERT_TRUE(CompareWithGoldenTemplate(screenshotFilename, "GT.ppm", static_cast<float>(comparisonThreshold)));
            break;
        }
    }
}

} // namespace

INSTANTIATE_TEST_SUITE_P(D3D12, OffscreenSceneTest, ::testing::Values(RHIType::D3D12));
INSTANTIATE_TEST_SUITE_P(OpenGL, OffscreenSceneTest, ::testing::Values(RHIType::OpenGL));
#if defined(XCENGINE_SUPPORT_VULKAN)
INSTANTIATE_TEST_SUITE_P(Vulkan, OffscreenSceneTest, ::testing::Values(RHIType::Vulkan));
#endif

GTEST_API_ int main(int argc, char** argv) {
    Logger::Get().Initialize();
    Logger::Get().AddSink(std::make_unique<ConsoleLogSink>());
    Logger::Get().SetMinimumLevel(LogLevel::Debug);

    testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}