#include <gtest/gtest.h>

#include "Platform/D3D12WindowRenderer.h"
#include "XCUIBackend/IEditorHostCompositor.h"
#include "XCUIBackend/ImGuiWindowUICompositor.h"
#include "XCUIBackend/UITextureRegistration.h"

#include <array>
#include <cstdint>
#include <memory>
#include <string>
#include <utility>
#include <vector>

namespace {

using XCEngine::Editor::Platform::D3D12WindowRenderer;
using XCEngine::Editor::XCUIBackend::IEditorHostCompositor;
using XCEngine::Editor::XCUIBackend::ImGuiWindowUICompositor;
using XCEngine::Editor::XCUIBackend::UITextureRegistration;

class RecordingHostCompositor final : public IEditorHostCompositor {
public:
    bool initializeResult = true;
    bool handleWindowMessageResult = false;
    bool createTextureDescriptorResult = false;
    bool invokeConfigureFonts = false;

    int initializeCount = 0;
    int shutdownCount = 0;
    int beginFrameCount = 0;
    int endFrameCount = 0;
    int handleWindowMessageCount = 0;
    int createTextureDescriptorCount = 0;
    int freeTextureDescriptorCount = 0;

    HWND lastHwnd = nullptr;
    UINT lastMessage = 0u;
    WPARAM lastWParam = 0u;
    LPARAM lastLParam = 0u;

    D3D12WindowRenderer* initializedRenderer = nullptr;
    D3D12WindowRenderer* presentedRenderer = nullptr;
    ::XCEngine::RHI::RHIDevice* lastDevice = nullptr;
    ::XCEngine::RHI::RHITexture* lastTexture = nullptr;

    bool beforeUiRenderProvided = false;
    bool afterUiRenderProvided = false;

    std::array<float, 4> lastClearColor = { 0.0f, 0.0f, 0.0f, 0.0f };
    UITextureRegistration nextRegistration = {};
    UITextureRegistration freedRegistration = {};
    std::vector<std::string> callOrder = {};

    bool Initialize(
        HWND hwnd,
        D3D12WindowRenderer& windowRenderer,
        const ConfigureFontsCallback& configureFonts) override {
        ++initializeCount;
        lastHwnd = hwnd;
        initializedRenderer = &windowRenderer;
        callOrder.push_back("initialize");
        if (invokeConfigureFonts && configureFonts) {
            configureFonts();
        }
        return initializeResult;
    }

    void Shutdown() override {
        ++shutdownCount;
        callOrder.push_back("shutdown");
    }

    bool HandleWindowMessage(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) override {
        ++handleWindowMessageCount;
        lastHwnd = hwnd;
        lastMessage = message;
        lastWParam = wParam;
        lastLParam = lParam;
        callOrder.push_back("message");
        return handleWindowMessageResult;
    }

    void BeginFrame() override {
        ++beginFrameCount;
        callOrder.push_back("begin");
    }

    void EndFrameAndPresent(
        D3D12WindowRenderer& windowRenderer,
        const float clearColor[4],
        const RenderCallback& beforeUiRender,
        const RenderCallback& afterUiRender) override {
        ++endFrameCount;
        presentedRenderer = &windowRenderer;
        beforeUiRenderProvided = static_cast<bool>(beforeUiRender);
        afterUiRenderProvided = static_cast<bool>(afterUiRender);
        for (std::size_t index = 0; index < lastClearColor.size(); ++index) {
            lastClearColor[index] = clearColor[index];
        }
        callOrder.push_back("present");
    }

    bool CreateTextureDescriptor(
        ::XCEngine::RHI::RHIDevice* device,
        ::XCEngine::RHI::RHITexture* texture,
        UITextureRegistration& outRegistration) override {
        ++createTextureDescriptorCount;
        lastDevice = device;
        lastTexture = texture;
        if (createTextureDescriptorResult) {
            outRegistration = nextRegistration;
        }
        return createTextureDescriptorResult;
    }

    void FreeTextureDescriptor(const UITextureRegistration& registration) override {
        ++freeTextureDescriptorCount;
        freedRegistration = registration;
    }
};

HWND MakeFakeHwnd() {
    return reinterpret_cast<HWND>(static_cast<std::uintptr_t>(0x1234u));
}

UITextureRegistration MakeRegistration() {
    UITextureRegistration registration = {};
    registration.cpuHandle.ptr = 11u;
    registration.gpuHandle.ptr = 29u;
    registration.texture.nativeHandle = 43u;
    registration.texture.width = 256u;
    registration.texture.height = 128u;
    registration.texture.kind = ::XCEngine::UI::UITextureHandleKind::ShaderResourceView;
    return registration;
}

TEST(ImGuiWindowUICompositorTest, InitializeForwardsToHostAndConfigureFontsCallback) {
    auto host = std::make_unique<RecordingHostCompositor>();
    RecordingHostCompositor* hostPtr = host.get();
    hostPtr->invokeConfigureFonts = true;

    ImGuiWindowUICompositor compositor(std::move(host));
    D3D12WindowRenderer renderer = {};
    bool configureFontsCalled = false;

    EXPECT_TRUE(compositor.Initialize(
        MakeFakeHwnd(),
        renderer,
        [&configureFontsCalled]() { configureFontsCalled = true; }));
    EXPECT_TRUE(configureFontsCalled);
    ASSERT_NE(hostPtr, nullptr);
    EXPECT_EQ(hostPtr->initializeCount, 1);
    EXPECT_EQ(hostPtr->lastHwnd, MakeFakeHwnd());
    EXPECT_EQ(hostPtr->initializedRenderer, &renderer);
}

TEST(ImGuiWindowUICompositorTest, RenderFrameCallsHostBeginUiAndPresentInOrder) {
    auto host = std::make_unique<RecordingHostCompositor>();
    RecordingHostCompositor* hostPtr = host.get();

    ImGuiWindowUICompositor compositor(std::move(host));
    D3D12WindowRenderer renderer = {};
    ASSERT_TRUE(compositor.Initialize(MakeFakeHwnd(), renderer, {}));
    hostPtr->callOrder.clear();

    bool uiRendered = false;
    constexpr float clearColor[4] = { 0.1f, 0.2f, 0.3f, 0.4f };
    compositor.RenderFrame(
        clearColor,
        [&]() {
            uiRendered = true;
            hostPtr->callOrder.push_back("ui");
        },
        [](const ::XCEngine::Rendering::RenderContext&, const ::XCEngine::Rendering::RenderSurface&) {},
        [](const ::XCEngine::Rendering::RenderContext&, const ::XCEngine::Rendering::RenderSurface&) {});

    EXPECT_TRUE(uiRendered);
    EXPECT_EQ(hostPtr->beginFrameCount, 1);
    EXPECT_EQ(hostPtr->endFrameCount, 1);
    EXPECT_EQ(hostPtr->presentedRenderer, &renderer);
    EXPECT_TRUE(hostPtr->beforeUiRenderProvided);
    EXPECT_TRUE(hostPtr->afterUiRenderProvided);
    EXPECT_EQ(hostPtr->lastClearColor[0], clearColor[0]);
    EXPECT_EQ(hostPtr->lastClearColor[1], clearColor[1]);
    EXPECT_EQ(hostPtr->lastClearColor[2], clearColor[2]);
    EXPECT_EQ(hostPtr->lastClearColor[3], clearColor[3]);
    EXPECT_EQ(
        hostPtr->callOrder,
        (std::vector<std::string>{ "begin", "ui", "present" }));
}

TEST(ImGuiWindowUICompositorTest, RenderFrameWithoutUiCallbackStillBeginsAndPresents) {
    auto host = std::make_unique<RecordingHostCompositor>();
    RecordingHostCompositor* hostPtr = host.get();

    ImGuiWindowUICompositor compositor(std::move(host));
    D3D12WindowRenderer renderer = {};
    ASSERT_TRUE(compositor.Initialize(MakeFakeHwnd(), renderer, {}));
    hostPtr->callOrder.clear();

    constexpr float clearColor[4] = { 0.7f, 0.6f, 0.5f, 0.4f };
    compositor.RenderFrame(clearColor, {}, {}, {});

    EXPECT_EQ(hostPtr->beginFrameCount, 1);
    EXPECT_EQ(hostPtr->endFrameCount, 1);
    EXPECT_EQ(hostPtr->presentedRenderer, &renderer);
    EXPECT_FALSE(hostPtr->beforeUiRenderProvided);
    EXPECT_FALSE(hostPtr->afterUiRenderProvided);
    EXPECT_EQ(hostPtr->lastClearColor[0], clearColor[0]);
    EXPECT_EQ(hostPtr->lastClearColor[1], clearColor[1]);
    EXPECT_EQ(hostPtr->lastClearColor[2], clearColor[2]);
    EXPECT_EQ(hostPtr->lastClearColor[3], clearColor[3]);
    EXPECT_EQ(
        hostPtr->callOrder,
        (std::vector<std::string>{ "begin", "present" }));
}

TEST(ImGuiWindowUICompositorTest, HandleWindowMessageAndTextureRegistrationForwardToHost) {
    auto host = std::make_unique<RecordingHostCompositor>();
    RecordingHostCompositor* hostPtr = host.get();
    hostPtr->handleWindowMessageResult = true;
    hostPtr->createTextureDescriptorResult = true;
    hostPtr->nextRegistration = MakeRegistration();

    ImGuiWindowUICompositor compositor(std::move(host));

    EXPECT_TRUE(compositor.HandleWindowMessage(MakeFakeHwnd(), WM_SIZE, 7u, 19u));
    EXPECT_EQ(hostPtr->handleWindowMessageCount, 1);
    EXPECT_EQ(hostPtr->lastMessage, static_cast<UINT>(WM_SIZE));
    EXPECT_EQ(hostPtr->lastWParam, static_cast<WPARAM>(7u));
    EXPECT_EQ(hostPtr->lastLParam, static_cast<LPARAM>(19u));

    UITextureRegistration registration = {};
    auto* fakeDevice = reinterpret_cast<::XCEngine::RHI::RHIDevice*>(static_cast<std::uintptr_t>(0x41u));
    auto* fakeTexture = reinterpret_cast<::XCEngine::RHI::RHITexture*>(static_cast<std::uintptr_t>(0x59u));
    EXPECT_TRUE(compositor.CreateTextureDescriptor(fakeDevice, fakeTexture, registration));
    EXPECT_EQ(hostPtr->createTextureDescriptorCount, 1);
    EXPECT_EQ(hostPtr->lastDevice, fakeDevice);
    EXPECT_EQ(hostPtr->lastTexture, fakeTexture);
    EXPECT_EQ(registration.cpuHandle.ptr, hostPtr->nextRegistration.cpuHandle.ptr);
    EXPECT_EQ(registration.gpuHandle.ptr, hostPtr->nextRegistration.gpuHandle.ptr);
    EXPECT_EQ(registration.texture.nativeHandle, hostPtr->nextRegistration.texture.nativeHandle);

    compositor.FreeTextureDescriptor(registration);
    EXPECT_EQ(hostPtr->freeTextureDescriptorCount, 1);
    EXPECT_EQ(hostPtr->freedRegistration.cpuHandle.ptr, registration.cpuHandle.ptr);
    EXPECT_EQ(hostPtr->freedRegistration.gpuHandle.ptr, registration.gpuHandle.ptr);
    EXPECT_EQ(hostPtr->freedRegistration.texture.nativeHandle, registration.texture.nativeHandle);
}

TEST(ImGuiWindowUICompositorTest, SecondInitializeRebindsRendererForSubsequentFrames) {
    auto host = std::make_unique<RecordingHostCompositor>();
    RecordingHostCompositor* hostPtr = host.get();

    ImGuiWindowUICompositor compositor(std::move(host));
    D3D12WindowRenderer firstRenderer = {};
    D3D12WindowRenderer secondRenderer = {};

    ASSERT_TRUE(compositor.Initialize(MakeFakeHwnd(), firstRenderer, {}));
    ASSERT_TRUE(compositor.Initialize(MakeFakeHwnd(), secondRenderer, {}));
    EXPECT_EQ(hostPtr->initializeCount, 2);
    EXPECT_EQ(hostPtr->initializedRenderer, &secondRenderer);

    compositor.RenderFrame(
        std::array<float, 4>{ 0.2f, 0.3f, 0.4f, 1.0f }.data(),
        []() {},
        {},
        {});

    EXPECT_EQ(hostPtr->beginFrameCount, 1);
    EXPECT_EQ(hostPtr->endFrameCount, 1);
    EXPECT_EQ(hostPtr->presentedRenderer, &secondRenderer);
}

TEST(ImGuiWindowUICompositorTest, ShutdownClearsRendererBindingAndPreventsFurtherRender) {
    auto host = std::make_unique<RecordingHostCompositor>();
    RecordingHostCompositor* hostPtr = host.get();

    ImGuiWindowUICompositor compositor(std::move(host));
    D3D12WindowRenderer renderer = {};
    ASSERT_TRUE(compositor.Initialize(MakeFakeHwnd(), renderer, {}));

    bool firstUiRendered = false;
    compositor.RenderFrame(
        std::array<float, 4>{ 0.0f, 0.0f, 0.0f, 1.0f }.data(),
        [&]() { firstUiRendered = true; },
        {},
        {});
    EXPECT_TRUE(firstUiRendered);
    EXPECT_EQ(hostPtr->beginFrameCount, 1);
    EXPECT_EQ(hostPtr->endFrameCount, 1);

    compositor.Shutdown();
    EXPECT_EQ(hostPtr->shutdownCount, 1);

    bool secondUiRendered = false;
    compositor.RenderFrame(
        std::array<float, 4>{ 1.0f, 0.0f, 0.0f, 1.0f }.data(),
        [&]() { secondUiRendered = true; },
        {},
        {});
    EXPECT_FALSE(secondUiRendered);
    EXPECT_EQ(hostPtr->beginFrameCount, 1);
    EXPECT_EQ(hostPtr->endFrameCount, 1);
}

TEST(ImGuiWindowUICompositorTest, NullHostCompositorReturnsSafeDefaults) {
    ImGuiWindowUICompositor compositor(std::unique_ptr<IEditorHostCompositor>{});
    D3D12WindowRenderer renderer = {};

    bool configureFontsCalled = false;
    EXPECT_FALSE(compositor.Initialize(
        MakeFakeHwnd(),
        renderer,
        [&configureFontsCalled]() { configureFontsCalled = true; }));
    EXPECT_FALSE(configureFontsCalled);
    EXPECT_FALSE(compositor.HandleWindowMessage(MakeFakeHwnd(), WM_CLOSE, 0u, 0u));

    UITextureRegistration registration = {};
    EXPECT_FALSE(compositor.CreateTextureDescriptor(nullptr, nullptr, registration));

    bool uiRendered = false;
    compositor.RenderFrame(
        std::array<float, 4>{ 0.0f, 0.0f, 0.0f, 1.0f }.data(),
        [&]() { uiRendered = true; },
        {},
        {});
    EXPECT_FALSE(uiRendered);

    compositor.Shutdown();
}

} // namespace