#include "Application.h"
#include "XCUIBackend/ImGuiXCUIPanelCanvasHost.h"
#include "XCUIBackend/ImGuiXCUIHostedPreviewPresenter.h"
#include "XCUIBackend/ImGuiWindowUICompositor.h"

#include <XCEngine/Core/Asset/ResourceManager.h>

#include <imgui.h>

#include <algorithm>
#include <cmath>

namespace XCEngine {
namespace NewEditor {

namespace {
constexpr wchar_t kWindowClassName[] = L"XCNewEditorWindowClass";
constexpr wchar_t kWindowTitle[] = L"XCNewEditor";
constexpr float kClearColor[4] = { 0.08f, 0.09f, 0.11f, 1.0f };
constexpr float kHostedPreviewClearColor[4] = { 0.0f, 0.0f, 0.0f, 0.0f };

template <typename ResourceType>
void ShutdownAndDelete(ResourceType*& resource) {
    if (resource == nullptr) {
        return;
    }

    resource->Shutdown();
    delete resource;
    resource = nullptr;
}

void ConfigureFonts() {
    ImGuiIO& io = ImGui::GetIO();
    ImFont* uiFont = nullptr;
    ::XCEngine::Editor::XCUIBackend::BuildDefaultXCUIEditorFontAtlas(*io.Fonts, uiFont);
    io.FontDefault = uiFont;
}

const char* GetHostedPreviewPathLabel(bool nativeRequested, bool nativePresenterBound) {
    if (nativeRequested && nativePresenterBound) {
        return "native queued offscreen surface";
    }
    if (nativeRequested) {
        return "native requested, hosted presenter bound";
    }
    if (nativePresenterBound) {
        return "hosted presenter requested, native presenter still bound";
    }
    return "hosted presenter";
}

const char* GetHostedPreviewStateLabel(
    bool hostedPreviewEnabled,
    bool nativePresenterBound,
    bool presentedThisFrame,
    bool queuedToNativePassThisFrame,
    bool surfaceImageAvailable,
    bool surfaceAllocated,
    bool surfaceReady,
    bool descriptorAvailable) {
    if (!hostedPreviewEnabled) {
        return "disabled";
    }

    if (nativePresenterBound) {
        if (surfaceImageAvailable && surfaceReady) {
            return "live";
        }
        if (queuedToNativePassThisFrame || surfaceAllocated || descriptorAvailable) {
            return "warming";
        }
        return "awaiting submit";
    }

    if (presentedThisFrame) {
        return "live";
    }
    return "idle";
}
} // namespace

std::unique_ptr<::XCEngine::Editor::XCUIBackend::IXCUIHostedPreviewPresenter>
Application::CreateHostedPreviewPresenter(bool nativePreview) {
    if (nativePreview) {
        return ::XCEngine::Editor::XCUIBackend::CreateQueuedNativeXCUIHostedPreviewPresenter(
            m_hostedPreviewQueue,
            m_hostedPreviewSurfaceRegistry);
    }

    return ::XCEngine::Editor::XCUIBackend::CreateImGuiXCUIHostedPreviewPresenter();
}

const Application::ShellPanelChromeState* Application::TryGetShellPanelState(ShellPanelId panelId) const {
    return m_shellChromeState.TryGetPanelState(panelId);
}

bool Application::IsShellViewToggleEnabled(ShellViewToggleId toggleId) const {
    return m_shellChromeState.GetViewToggle(toggleId);
}

void Application::SetShellViewToggleEnabled(ShellViewToggleId toggleId, bool enabled) {
    m_shellChromeState.SetViewToggle(toggleId, enabled);
}

bool Application::IsNativeHostedPreviewEnabled(ShellPanelId panelId) const {
    return m_shellChromeState.IsNativeHostedPreviewActive(panelId);
}

void Application::ConfigureHostedPreviewPresenters() {
    const ShellPanelChromeState* demoState = TryGetShellPanelState(ShellPanelId::XCUIDemo);
    if (m_demoPanel != nullptr) {
        m_demoPanel->SetVisible(demoState != nullptr && demoState->visible);
        m_demoPanel->SetHostedPreviewEnabled(demoState == nullptr || demoState->hostedPreviewEnabled);
        m_demoPanel->SetHostedPreviewPresenter(CreateHostedPreviewPresenter(IsNativeHostedPreviewEnabled(ShellPanelId::XCUIDemo)));
    }

    const ShellPanelChromeState* layoutLabState = TryGetShellPanelState(ShellPanelId::XCUILayoutLab);
    if (m_layoutLabPanel != nullptr) {
        m_layoutLabPanel->SetVisible(layoutLabState != nullptr && layoutLabState->visible);
        m_layoutLabPanel->SetHostedPreviewEnabled(layoutLabState == nullptr || layoutLabState->hostedPreviewEnabled);
        m_layoutLabPanel->SetHostedPreviewPresenter(
            CreateHostedPreviewPresenter(IsNativeHostedPreviewEnabled(ShellPanelId::XCUILayoutLab)));
    }
}

void Application::ConfigureShellCommandRouter() {
    m_shellCommandRouter.Clear();

    ShellCommandBindings bindings = {};
    bindings.getXCUIDemoPanelVisible = [this]() {
        return m_shellChromeState.IsPanelVisible(ShellPanelId::XCUIDemo);
    };
    bindings.setXCUIDemoPanelVisible = [this](bool visible) {
        m_shellChromeState.SetPanelVisible(ShellPanelId::XCUIDemo, visible);
        if (m_demoPanel != nullptr) {
            m_demoPanel->SetVisible(visible);
        }
    };
    bindings.getXCUILayoutLabPanelVisible = [this]() {
        return m_shellChromeState.IsPanelVisible(ShellPanelId::XCUILayoutLab);
    };
    bindings.setXCUILayoutLabPanelVisible = [this](bool visible) {
        m_shellChromeState.SetPanelVisible(ShellPanelId::XCUILayoutLab, visible);
        if (m_layoutLabPanel != nullptr) {
            m_layoutLabPanel->SetVisible(visible);
        }
    };
    bindings.getImGuiDemoWindowVisible = [this]() {
        return IsShellViewToggleEnabled(ShellViewToggleId::ImGuiDemoWindow);
    };
    bindings.setImGuiDemoWindowVisible = [this](bool visible) {
        SetShellViewToggleEnabled(ShellViewToggleId::ImGuiDemoWindow, visible);
    };
    bindings.getNativeBackdropVisible = [this]() {
        return IsShellViewToggleEnabled(ShellViewToggleId::NativeBackdrop);
    };
    bindings.setNativeBackdropVisible = [this](bool visible) {
        SetShellViewToggleEnabled(ShellViewToggleId::NativeBackdrop, visible);
    };
    bindings.getPulseAccentEnabled = [this]() {
        return IsShellViewToggleEnabled(ShellViewToggleId::PulseAccent);
    };
    bindings.setPulseAccentEnabled = [this](bool enabled) {
        SetShellViewToggleEnabled(ShellViewToggleId::PulseAccent, enabled);
    };
    bindings.getNativeXCUIOverlayVisible = [this]() {
        return IsShellViewToggleEnabled(ShellViewToggleId::NativeXCUIOverlay);
    };
    bindings.setNativeXCUIOverlayVisible = [this](bool visible) {
        SetShellViewToggleEnabled(ShellViewToggleId::NativeXCUIOverlay, visible);
    };
    bindings.getHostedPreviewHudVisible = [this]() {
        return IsShellViewToggleEnabled(ShellViewToggleId::HostedPreviewHud);
    };
    bindings.setHostedPreviewHudVisible = [this](bool visible) {
        SetShellViewToggleEnabled(ShellViewToggleId::HostedPreviewHud, visible);
    };
    bindings.getNativeDemoPanelPreviewEnabled = [this]() {
        return IsNativeHostedPreviewEnabled(ShellPanelId::XCUIDemo);
    };
    bindings.setNativeDemoPanelPreviewEnabled = [this](bool enabled) {
        m_shellChromeState.SetHostedPreviewMode(
            ShellPanelId::XCUIDemo,
            enabled ? ShellHostedPreviewMode::NativeOffscreen : ShellHostedPreviewMode::HostedPresenter);
    };
    bindings.getNativeLayoutLabPreviewEnabled = [this]() {
        return IsNativeHostedPreviewEnabled(ShellPanelId::XCUILayoutLab);
    };
    bindings.setNativeLayoutLabPreviewEnabled = [this](bool enabled) {
        m_shellChromeState.SetHostedPreviewMode(
            ShellPanelId::XCUILayoutLab,
            enabled ? ShellHostedPreviewMode::NativeOffscreen : ShellHostedPreviewMode::HostedPresenter);
    };
    bindings.onHostedPreviewModeChanged = [this]() { ConfigureHostedPreviewPresenters(); };

    Application::RegisterShellViewCommands(m_shellCommandRouter, bindings);
}

void Application::DispatchShellShortcuts() {
    ::XCEngine::Editor::XCUIBackend::XCUIInputBridgeCaptureOptions options = {};
    ::XCEngine::Editor::XCUIBackend::XCUIInputBridgeFrameSnapshot snapshot =
        m_xcuiInputSource.CaptureSnapshot(options);

    ImGuiIO& io = ImGui::GetIO();
    snapshot.wantCaptureKeyboard = io.WantCaptureKeyboard;
    snapshot.wantTextInput = io.WantTextInput;

    const ::XCEngine::Editor::XCUIBackend::XCUIInputBridgeFrameDelta frameDelta =
        m_shellInputBridge.Translate(snapshot);
    const ::XCEngine::Editor::XCUIBackend::XCUIEditorCommandInputSnapshot commandSnapshot =
        Application::BuildShellShortcutSnapshot(frameDelta);
    m_shellCommandRouter.InvokeMatchingShortcut({ &commandSnapshot });
}

Application::HostedPreviewPanelDiagnostics Application::BuildHostedPreviewPanelDiagnostics(
    const char* debugName,
    const char* fallbackDebugSource,
    bool visible,
    bool hostedPreviewEnabled,
    bool nativeRequested,
    bool nativePresenterBound,
    const ::XCEngine::Editor::XCUIBackend::XCUIHostedPreviewStats& previewStats) const {
    HostedPreviewPanelDiagnostics diagnostics = {};
    if (debugName != nullptr) {
        diagnostics.debugName = debugName;
    }
    if (fallbackDebugSource != nullptr) {
        diagnostics.debugSource = fallbackDebugSource;
    }

    diagnostics.visible = visible;
    diagnostics.hostedPreviewEnabled = hostedPreviewEnabled;
    diagnostics.nativeRequested = nativeRequested;
    diagnostics.nativePresenterBound = nativePresenterBound;
    diagnostics.presentedThisFrame = previewStats.presented;
    diagnostics.queuedToNativePassThisFrame = previewStats.queuedToNativePass;
    diagnostics.submittedDrawListCount = previewStats.submittedDrawListCount;
    diagnostics.submittedCommandCount = previewStats.submittedCommandCount;
    diagnostics.flushedDrawListCount = previewStats.flushedDrawListCount;
    diagnostics.flushedCommandCount = previewStats.flushedCommandCount;

    ::XCEngine::Editor::XCUIBackend::XCUIHostedPreviewSurfaceDescriptor descriptor = {};
    if (!diagnostics.debugName.empty() &&
        m_hostedPreviewSurfaceRegistry.TryGetSurfaceDescriptor(diagnostics.debugName.c_str(), descriptor)) {
        diagnostics.descriptorAvailable = true;
        diagnostics.surfaceImageAvailable = descriptor.image.IsValid();
        diagnostics.surfaceWidth = descriptor.image.surfaceWidth;
        diagnostics.surfaceHeight = descriptor.image.surfaceHeight;
        diagnostics.logicalWidth = descriptor.logicalSize.width;
        diagnostics.logicalHeight = descriptor.logicalSize.height;
        diagnostics.queuedFrameIndex = descriptor.queuedFrameIndex;
        if (!descriptor.debugSource.empty()) {
            diagnostics.debugSource = descriptor.debugSource;
        }
    }

    if (!diagnostics.debugName.empty()) {
        const HostedPreviewOffscreenSurface* previewSurface = FindHostedPreviewSurface(diagnostics.debugName);
        if (previewSurface != nullptr) {
            diagnostics.surfaceAllocated =
                previewSurface->colorTexture != nullptr ||
                previewSurface->colorView != nullptr ||
                previewSurface->width > 0u ||
                previewSurface->height > 0u;
            diagnostics.surfaceReady = previewSurface->IsReady();
            if (diagnostics.surfaceWidth == 0u) {
                diagnostics.surfaceWidth = previewSurface->width;
            }
            if (diagnostics.surfaceHeight == 0u) {
                diagnostics.surfaceHeight = previewSurface->height;
            }
        }
    }

    return diagnostics;
}

int Application::Run(HINSTANCE instance, int nCmdShow) {
    if (!CreateMainWindow(instance, nCmdShow)) {
        return -1;
    }

    m_xcuiInputSource.Reset();

    auto& resourceManager = ::XCEngine::Resources::ResourceManager::Get();
    resourceManager.Initialize();
    resourceManager.SetResourceRoot(XCENGINE_NEW_EDITOR_REPO_ROOT);

    if (!InitializeRenderer()) {
        resourceManager.Shutdown();
        return -1;
    }

    InitializeWindowCompositor();
    m_demoPanel = std::make_unique<XCUIDemoPanel>(
        &m_xcuiInputSource,
        CreateHostedPreviewPresenter(IsNativeHostedPreviewEnabled(ShellPanelId::XCUIDemo)),
        ::XCEngine::Editor::XCUIBackend::CreateImGuiXCUIPanelCanvasHost());
    m_layoutLabPanel = std::make_unique<XCUILayoutLabPanel>(
        &m_xcuiInputSource,
        CreateHostedPreviewPresenter(IsNativeHostedPreviewEnabled(ShellPanelId::XCUILayoutLab)),
        ::XCEngine::Editor::XCUIBackend::CreateImGuiXCUIPanelCanvasHost());
    ConfigureHostedPreviewPresenters();
    m_shellInputBridge.Reset();
    ConfigureShellCommandRouter();
    m_running = true;
    m_renderReady = true;

    MSG message = {};
    while (m_running) {
        while (PeekMessageW(&message, nullptr, 0, 0, PM_REMOVE)) {
            if (message.message == WM_QUIT) {
                m_running = false;
                break;
            }

            TranslateMessage(&message);
            DispatchMessageW(&message);
        }

        if (!m_running) {
            break;
        }

        Frame();
    }

    m_demoPanel.reset();
    m_layoutLabPanel.reset();
    ShutdownWindowCompositor();
    ShutdownRenderer();
    resourceManager.Shutdown();
    return static_cast<int>(message.wParam);
}

LRESULT CALLBACK Application::StaticWndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) {
    Application* app = reinterpret_cast<Application*>(GetWindowLongPtrW(hwnd, GWLP_USERDATA));
    if (message == WM_NCCREATE) {
        const CREATESTRUCTW* createStruct = reinterpret_cast<const CREATESTRUCTW*>(lParam);
        app = reinterpret_cast<Application*>(createStruct->lpCreateParams);
        SetWindowLongPtrW(hwnd, GWLP_USERDATA, reinterpret_cast<LONG_PTR>(app));
    }

    return app != nullptr
        ? app->WndProc(hwnd, message, wParam, lParam)
        : DefWindowProcW(hwnd, message, wParam, lParam);
}

LRESULT Application::WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) {
    m_xcuiInputSource.HandleWindowMessage(hwnd, message, wParam, lParam);

    if (m_windowCompositor != nullptr &&
        m_windowCompositor->HandleWindowMessage(hwnd, message, wParam, lParam)) {
        return true;
    }

    switch (message) {
    case WM_SIZE:
        if (wParam != SIZE_MINIMIZED && m_renderReady) {
            m_windowRenderer.Resize(static_cast<int>(LOWORD(lParam)), static_cast<int>(HIWORD(lParam)));
        }
        return 0;
    case WM_CLOSE:
        DestroyWindow(hwnd);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    case WM_PAINT: {
        PAINTSTRUCT paintStruct = {};
        BeginPaint(hwnd, &paintStruct);
        if (m_renderReady) {
            Frame();
        }
        EndPaint(hwnd, &paintStruct);
        return 0;
    }
    default:
        return DefWindowProcW(hwnd, message, wParam, lParam);
    }
}

bool Application::CreateMainWindow(HINSTANCE instance, int nCmdShow) {
    WNDCLASSEXW windowClass = {};
    windowClass.cbSize = sizeof(windowClass);
    windowClass.style = CS_HREDRAW | CS_VREDRAW;
    windowClass.lpfnWndProc = &Application::StaticWndProc;
    windowClass.hInstance = instance;
    windowClass.hCursor = LoadCursorW(nullptr, IDC_ARROW);
    windowClass.lpszClassName = kWindowClassName;
    if (!RegisterClassExW(&windowClass)) {
        return false;
    }

    m_hwnd = CreateWindowExW(
        0,
        kWindowClassName,
        kWindowTitle,
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        1360,
        840,
        nullptr,
        nullptr,
        instance,
        this);
    if (m_hwnd == nullptr) {
        return false;
    }

    ShowWindow(m_hwnd, nCmdShow);
    UpdateWindow(m_hwnd);
    return true;
}

bool Application::InitializeRenderer() {
    RECT clientRect = {};
    if (!GetClientRect(m_hwnd, &clientRect)) {
        return false;
    }

    const int width = clientRect.right - clientRect.left;
    const int height = clientRect.bottom - clientRect.top;
    const bool initialized = width > 0 &&
        height > 0 &&
        m_windowRenderer.Initialize(m_hwnd, width, height);
    if (initialized) {
        m_startTime = std::chrono::steady_clock::now();
    }
    return initialized;
}

void Application::InitializeWindowCompositor() {
    m_windowCompositor = ::XCEngine::Editor::XCUIBackend::CreateImGuiWindowUICompositor();
    if (m_windowCompositor != nullptr) {
        m_windowCompositor->Initialize(
            m_hwnd,
            m_windowRenderer,
            []() { ConfigureFonts(); });
    }
}

void Application::ShutdownWindowCompositor() {
    DestroyHostedPreviewSurfaces();
    if (m_windowCompositor != nullptr) {
        m_windowCompositor->Shutdown();
        m_windowCompositor.reset();
    }
}

void Application::ShutdownRenderer() {
    m_renderReady = false;
    m_hostedPreviewRenderBackend.Shutdown();
    m_nativeBackdropRenderer.Shutdown();
    m_windowRenderer.Shutdown();
}

void Application::DestroyHostedPreviewSurfaces() {
    for (HostedPreviewOffscreenSurface& previewSurface : m_hostedPreviewSurfaces) {
        if (previewSurface.textureRegistration.cpuHandle.ptr != 0) {
            if (m_windowCompositor != nullptr) {
                m_windowCompositor->FreeTextureDescriptor(previewSurface.textureRegistration);
            }
        }
        ShutdownAndDelete(previewSurface.colorView);
        ShutdownAndDelete(previewSurface.colorTexture);
        previewSurface = {};
    }
    m_hostedPreviewSurfaces.clear();
}

void Application::SyncShellChromePanelStateFromPanels() {
    m_shellChromeState.SetPanelVisible(
        ShellPanelId::XCUIDemo,
        m_demoPanel != nullptr && m_demoPanel->IsVisible());
    m_shellChromeState.SetPanelVisible(
        ShellPanelId::XCUILayoutLab,
        m_layoutLabPanel != nullptr && m_layoutLabPanel->IsVisible());
}

void Application::SyncHostedPreviewSurfaces() {
    const auto isNativePreviewEnabled = [this](const std::string& debugName) {
        const ShellPanelChromeState* demoState = TryGetShellPanelState(ShellPanelId::XCUIDemo);
        if (demoState != nullptr &&
            debugName == demoState->previewDebugName &&
            IsNativeHostedPreviewEnabled(ShellPanelId::XCUIDemo)) {
            return true;
        }

        const ShellPanelChromeState* layoutLabState = TryGetShellPanelState(ShellPanelId::XCUILayoutLab);
        return layoutLabState != nullptr &&
            debugName == layoutLabState->previewDebugName &&
            IsNativeHostedPreviewEnabled(ShellPanelId::XCUILayoutLab);
    };

    const auto syncSurfaceForNameAndSize =
        [this, &isNativePreviewEnabled](
            const std::string& debugName,
            const ::XCEngine::UI::UISize& logicalSize) {
            if (!isNativePreviewEnabled(debugName)) {
                return;
            }

            const std::uint32_t width = logicalSize.width > 1.0f
                ? static_cast<std::uint32_t>(std::ceil(logicalSize.width))
                : 0u;
            const std::uint32_t height = logicalSize.height > 1.0f
                ? static_cast<std::uint32_t>(std::ceil(logicalSize.height))
                : 0u;
            if (width == 0u || height == 0u) {
                return;
            }

            HostedPreviewOffscreenSurface& previewSurface = FindOrAddHostedPreviewSurface(debugName);
            EnsureHostedPreviewSurface(previewSurface, width, height);
        };

    for (const auto& descriptor : m_hostedPreviewSurfaceRegistry.GetDescriptors()) {
        syncSurfaceForNameAndSize(descriptor.debugName, descriptor.logicalSize);
    }

    for (const auto& queuedFrame : m_hostedPreviewQueue.GetQueuedFrames()) {
        syncSurfaceForNameAndSize(queuedFrame.debugName, queuedFrame.logicalSize);
    }
}

Application::HostedPreviewOffscreenSurface* Application::FindHostedPreviewSurface(const std::string& debugName) {
    for (HostedPreviewOffscreenSurface& previewSurface : m_hostedPreviewSurfaces) {
        if (previewSurface.debugName == debugName) {
            return &previewSurface;
        }
    }

    return nullptr;
}

const Application::HostedPreviewOffscreenSurface* Application::FindHostedPreviewSurface(const std::string& debugName) const {
    for (const HostedPreviewOffscreenSurface& previewSurface : m_hostedPreviewSurfaces) {
        if (previewSurface.debugName == debugName) {
            return &previewSurface;
        }
    }

    return nullptr;
}

Application::HostedPreviewOffscreenSurface& Application::FindOrAddHostedPreviewSurface(const std::string& debugName) {
    HostedPreviewOffscreenSurface* existingSurface = FindHostedPreviewSurface(debugName);
    if (existingSurface != nullptr) {
        return *existingSurface;
    }

    HostedPreviewOffscreenSurface previewSurface = {};
    previewSurface.debugName = debugName;
    m_hostedPreviewSurfaces.push_back(std::move(previewSurface));
    return m_hostedPreviewSurfaces.back();
}

bool Application::EnsureHostedPreviewSurface(
    HostedPreviewOffscreenSurface& previewSurface,
    std::uint32_t width,
    std::uint32_t height) {
    if (previewSurface.IsReady() && previewSurface.width == width && previewSurface.height == height) {
        return true;
    }

    if (previewSurface.textureRegistration.cpuHandle.ptr != 0) {
        if (m_windowCompositor != nullptr) {
            m_windowCompositor->FreeTextureDescriptor(previewSurface.textureRegistration);
        }
    }
    ShutdownAndDelete(previewSurface.colorView);
    ShutdownAndDelete(previewSurface.colorTexture);
    previewSurface.textureRegistration = {};
    previewSurface.width = width;
    previewSurface.height = height;
    previewSurface.colorState = ::XCEngine::RHI::ResourceStates::Common;

    if (width == 0u || height == 0u) {
        return false;
    }

    ::XCEngine::RHI::TextureDesc colorDesc = {};
    colorDesc.width = width;
    colorDesc.height = height;
    colorDesc.depth = 1;
    colorDesc.mipLevels = 1;
    colorDesc.arraySize = 1;
    colorDesc.format = static_cast<std::uint32_t>(::XCEngine::RHI::Format::R8G8B8A8_UNorm);
    colorDesc.textureType = static_cast<std::uint32_t>(::XCEngine::RHI::TextureType::Texture2D);
    colorDesc.sampleCount = 1;
    previewSurface.colorTexture = m_windowRenderer.GetRHIDevice()->CreateTexture(colorDesc);
    if (previewSurface.colorTexture == nullptr) {
        return false;
    }

    ::XCEngine::RHI::ResourceViewDesc colorViewDesc = {};
    colorViewDesc.format = static_cast<std::uint32_t>(::XCEngine::RHI::Format::R8G8B8A8_UNorm);
    colorViewDesc.dimension = ::XCEngine::RHI::ResourceViewDimension::Texture2D;
    previewSurface.colorView =
        m_windowRenderer.GetRHIDevice()->CreateRenderTargetView(previewSurface.colorTexture, colorViewDesc);
    if (previewSurface.colorView == nullptr) {
        ShutdownAndDelete(previewSurface.colorTexture);
        return false;
    }

    if (m_windowCompositor == nullptr ||
        !m_windowCompositor->CreateTextureDescriptor(
        m_windowRenderer.GetRHIDevice(),
        previewSurface.colorTexture,
        previewSurface.textureRegistration)) {
        ShutdownAndDelete(previewSurface.colorView);
        ShutdownAndDelete(previewSurface.colorTexture);
        previewSurface.textureRegistration = {};
        return false;
    }

    return true;
}

bool Application::RenderHostedPreviewOffscreenSurface(
    HostedPreviewOffscreenSurface& previewSurface,
    const ::XCEngine::Rendering::RenderContext& renderContext,
    const ::XCEngine::UI::UIDrawData& drawData) {
    if (!previewSurface.IsReady() || renderContext.commandList == nullptr) {
        return false;
    }

    ::XCEngine::Rendering::RenderSurface renderSurface(previewSurface.width, previewSurface.height);
    renderSurface.SetColorAttachment(previewSurface.colorView);
    renderSurface.SetAutoTransitionEnabled(false);
    renderSurface.SetColorStateBefore(::XCEngine::RHI::ResourceStates::RenderTarget);
    renderSurface.SetColorStateAfter(::XCEngine::RHI::ResourceStates::RenderTarget);

    renderContext.commandList->TransitionBarrier(
        previewSurface.colorView,
        previewSurface.colorState,
        ::XCEngine::RHI::ResourceStates::RenderTarget);
    renderContext.commandList->SetRenderTargets(1, &previewSurface.colorView, nullptr);
    renderContext.commandList->ClearRenderTarget(previewSurface.colorView, kHostedPreviewClearColor);

    if (!m_hostedPreviewRenderBackend.Render(renderContext, renderSurface, drawData)) {
        previewSurface.colorState = ::XCEngine::RHI::ResourceStates::RenderTarget;
        return false;
    }

    renderContext.commandList->TransitionBarrier(
        previewSurface.colorView,
        ::XCEngine::RHI::ResourceStates::RenderTarget,
        ::XCEngine::RHI::ResourceStates::PixelShaderResource);
    previewSurface.colorState = ::XCEngine::RHI::ResourceStates::PixelShaderResource;
    return true;
}

void Application::RenderShellChrome() {
    SyncShellChromePanelStateFromPanels();

    ImGuiViewport* viewport = ImGui::GetMainViewport();
    if (viewport == nullptr) {
        return;
    }

    ImGuiWindowFlags windowFlags =
        ImGuiWindowFlags_NoDocking |
        ImGuiWindowFlags_NoTitleBar |
        ImGuiWindowFlags_NoCollapse |
        ImGuiWindowFlags_NoResize |
        ImGuiWindowFlags_NoMove |
        ImGuiWindowFlags_NoBringToFrontOnFocus |
        ImGuiWindowFlags_NoNavFocus |
        ImGuiWindowFlags_MenuBar;

    ImGui::SetNextWindowPos(viewport->WorkPos);
    ImGui::SetNextWindowSize(viewport->WorkSize);
    ImGui::SetNextWindowViewport(viewport->ID);
    ImGui::SetNextWindowBgAlpha(0.0f);
    ImGui::PushStyleVar(ImGuiStyleVar_WindowRounding, 0.0f);
    ImGui::PushStyleVar(ImGuiStyleVar_WindowBorderSize, 0.0f);
    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0.0f, 0.0f));
    const bool opened = ImGui::Begin("XCNewEditorShell", nullptr, windowFlags);
    ImGui::PopStyleVar(3);

    if (opened) {
        if (ImGui::BeginMenuBar()) {
            if (ImGui::BeginMenu("View")) {
                const auto drawCommandMenuItem =
                    [this](const char* label, const char* shortcut, bool selected, const char* commandId) {
                        const bool enabled = m_shellCommandRouter.IsCommandEnabled(commandId);
                        if (ImGui::MenuItem(label, shortcut, selected, enabled)) {
                            m_shellCommandRouter.InvokeCommand(commandId);
                        }
                    };

                drawCommandMenuItem(
                    "XCUI Demo",
                    "Ctrl+1",
                    TryGetShellPanelState(ShellPanelId::XCUIDemo) != nullptr &&
                        TryGetShellPanelState(ShellPanelId::XCUIDemo)->visible,
                    ShellCommandIds::ToggleXCUIDemoPanel);
                drawCommandMenuItem(
                    "XCUI Layout Lab",
                    "Ctrl+2",
                    TryGetShellPanelState(ShellPanelId::XCUILayoutLab) != nullptr &&
                        TryGetShellPanelState(ShellPanelId::XCUILayoutLab)->visible,
                    ShellCommandIds::ToggleXCUILayoutLabPanel);
                drawCommandMenuItem(
                    "ImGui Demo",
                    "Ctrl+3",
                    IsShellViewToggleEnabled(ShellViewToggleId::ImGuiDemoWindow),
                    ShellCommandIds::ToggleImGuiDemoWindow);
                ImGui::Separator();
                drawCommandMenuItem(
                    "Native Backdrop",
                    "Ctrl+Shift+B",
                    IsShellViewToggleEnabled(ShellViewToggleId::NativeBackdrop),
                    ShellCommandIds::ToggleNativeBackdrop);
                drawCommandMenuItem(
                    "Pulse Accent",
                    "Ctrl+Shift+P",
                    IsShellViewToggleEnabled(ShellViewToggleId::PulseAccent),
                    ShellCommandIds::TogglePulseAccent);
                drawCommandMenuItem(
                    "Native XCUI Overlay",
                    "Ctrl+Shift+O",
                    IsShellViewToggleEnabled(ShellViewToggleId::NativeXCUIOverlay),
                    ShellCommandIds::ToggleNativeXCUIOverlay);
                drawCommandMenuItem(
                    "Hosted Preview HUD",
                    "Ctrl+Shift+H",
                    IsShellViewToggleEnabled(ShellViewToggleId::HostedPreviewHud),
                    ShellCommandIds::ToggleHostedPreviewHud);
                drawCommandMenuItem(
                    "Native Demo Panel Preview",
                    "Ctrl+Alt+1",
                    IsNativeHostedPreviewEnabled(ShellPanelId::XCUIDemo),
                    ShellCommandIds::ToggleNativeDemoPanelPreview);
                drawCommandMenuItem(
                    "Native Layout Lab Preview",
                    "Ctrl+Alt+2",
                    IsNativeHostedPreviewEnabled(ShellPanelId::XCUILayoutLab),
                    ShellCommandIds::ToggleNativeLayoutLabPreview);
                ImGui::EndMenu();
            }

            ImGui::SeparatorText("XCUI Sandbox");
            const MainWindowNativeBackdropRenderer::OverlayStats& nativeOverlayStats =
                m_nativeBackdropRenderer.GetLastOverlayStats();
            const ::XCEngine::Editor::XCUIBackend::XCUILayoutLabFrameStats& overlayFrameStats =
                m_nativeOverlayRuntime.GetFrameResult().stats;
            const ::XCEngine::Editor::XCUIBackend::XCUIHostedPreviewDrainStats& hostedPreviewStats =
                m_hostedPreviewQueue.GetLastDrainStats();
            if (IsShellViewToggleEnabled(ShellViewToggleId::NativeXCUIOverlay)) {
                ImGui::TextDisabled(
                    "Native XCUI overlay: %s | runtime %zu cmds (%zu fill, %zu outline, %zu text, %zu image, clips %zu/%zu)",
                    overlayFrameStats.nativeOverlayReady ? "preflight OK" : "preflight issues",
                    overlayFrameStats.commandCount,
                    overlayFrameStats.filledRectCommandCount,
                    overlayFrameStats.rectOutlineCommandCount,
                    overlayFrameStats.textCommandCount,
                    overlayFrameStats.imageCommandCount,
                    overlayFrameStats.clipPushCommandCount,
                    overlayFrameStats.clipPopCommandCount);
                ImGui::TextDisabled(
                    "%s | supported %zu | unsupported %zu | prev native pass %zu cmds, %zu rendered, %zu skipped",
                    overlayFrameStats.nativeOverlayStatusMessage.empty()
                        ? "Overlay diagnostics unavailable"
                        : overlayFrameStats.nativeOverlayStatusMessage.c_str(),
                    overlayFrameStats.nativeSupportedCommandCount,
                    overlayFrameStats.nativeUnsupportedCommandCount,
                    nativeOverlayStats.commandCount,
                    nativeOverlayStats.renderedCommandCount,
                    nativeOverlayStats.skippedCommandCount);
            } else {
                ImGui::TextDisabled(
                    IsShellViewToggleEnabled(ShellViewToggleId::NativeBackdrop)
                        ? "Transition backend + runtime diagnostics + native backbuffer pass"
                        : "Transition backend + runtime diagnostics");
            }
            ImGui::TextDisabled(
                "Hosted preview queue: %zu frames | queued %zu cmds | rendered %zu cmds | skipped %zu cmds",
                hostedPreviewStats.queuedFrameCount,
                hostedPreviewStats.queuedCommandCount,
                hostedPreviewStats.renderedCommandCount,
                hostedPreviewStats.skippedCommandCount);
            std::size_t allocatedSurfaceCount = 0u;
            std::size_t readySurfaceCount = 0u;
            for (const HostedPreviewOffscreenSurface& previewSurface : m_hostedPreviewSurfaces) {
                if (previewSurface.colorTexture != nullptr || previewSurface.colorView != nullptr) {
                    ++allocatedSurfaceCount;
                }
                if (previewSurface.IsReady()) {
                    ++readySurfaceCount;
                }
            }
            ImGui::TextDisabled(
                "Hosted surfaces: %zu registry entries | %zu allocated | %zu ready",
                m_hostedPreviewSurfaceRegistry.GetDescriptors().size(),
                allocatedSurfaceCount,
                readySurfaceCount);
            if (m_demoPanel != nullptr) {
                ImGui::TextDisabled(
                    "XCUI Demo preview: %s",
                    IsNativeHostedPreviewEnabled(ShellPanelId::XCUIDemo)
                        ? "native offscreen preview surface"
                        : "hosted presenter");
            }
            if (m_layoutLabPanel != nullptr) {
                ImGui::TextDisabled(
                    "Layout Lab preview: %s",
                    IsNativeHostedPreviewEnabled(ShellPanelId::XCUILayoutLab)
                        ? "native offscreen preview surface"
                        : "hosted presenter");
            }
            ImGui::EndMenuBar();
        }

        ImGui::DockSpace(
            ImGui::GetID("XCNewEditorDockSpace"),
            ImVec2(0.0f, 0.0f),
            ImGuiDockNodeFlags_PassthruCentralNode);
    }

    ImGui::End();

    if (IsShellViewToggleEnabled(ShellViewToggleId::HostedPreviewHud)) {
        RenderHostedPreviewHud();
    }
}

void Application::RenderHostedPreviewHud() {
    ImGuiViewport* viewport = ImGui::GetMainViewport();
    if (viewport == nullptr) {
        return;
    }

    const ShellPanelChromeState* demoState = TryGetShellPanelState(ShellPanelId::XCUIDemo);
    const ShellPanelChromeState* layoutLabState = TryGetShellPanelState(ShellPanelId::XCUILayoutLab);
    const HostedPreviewPanelDiagnostics demoDiagnostics = BuildHostedPreviewPanelDiagnostics(
        demoState != nullptr ? demoState->previewDebugName.data() : "XCUI Demo",
        demoState != nullptr ? demoState->previewDebugSource.data() : "new_editor.panels.xcui_demo",
        demoState != nullptr && demoState->visible,
        demoState != nullptr && demoState->hostedPreviewEnabled,
        IsNativeHostedPreviewEnabled(ShellPanelId::XCUIDemo),
        m_demoPanel != nullptr && m_demoPanel->IsUsingNativeHostedPreview(),
        m_demoPanel != nullptr
            ? m_demoPanel->GetLastPreviewStats()
            : ::XCEngine::Editor::XCUIBackend::XCUIHostedPreviewStats{});
    const HostedPreviewPanelDiagnostics layoutLabDiagnostics = BuildHostedPreviewPanelDiagnostics(
        layoutLabState != nullptr ? layoutLabState->previewDebugName.data() : "XCUI Layout Lab",
        layoutLabState != nullptr ? layoutLabState->previewDebugSource.data() : "new_editor.panels.xcui_layout_lab",
        layoutLabState != nullptr && layoutLabState->visible,
        layoutLabState != nullptr && layoutLabState->hostedPreviewEnabled,
        IsNativeHostedPreviewEnabled(ShellPanelId::XCUILayoutLab),
        m_layoutLabPanel != nullptr && m_layoutLabPanel->IsUsingNativeHostedPreview(),
        m_layoutLabPanel != nullptr
            ? m_layoutLabPanel->GetLastPreviewStats()
            : ::XCEngine::Editor::XCUIBackend::XCUIHostedPreviewStats{});

    std::size_t allocatedSurfaceCount = 0u;
    std::size_t readySurfaceCount = 0u;
    for (const HostedPreviewOffscreenSurface& previewSurface : m_hostedPreviewSurfaces) {
        if (previewSurface.colorTexture != nullptr || previewSurface.colorView != nullptr) {
            ++allocatedSurfaceCount;
        }
        if (previewSurface.IsReady()) {
            ++readySurfaceCount;
        }
    }

    const ::XCEngine::Editor::XCUIBackend::XCUIHostedPreviewDrainStats& drainStats =
        m_hostedPreviewQueue.GetLastDrainStats();

    ImGuiWindowFlags windowFlags =
        ImGuiWindowFlags_NoDocking |
        ImGuiWindowFlags_NoSavedSettings |
        ImGuiWindowFlags_AlwaysAutoResize |
        ImGuiWindowFlags_NoFocusOnAppearing |
        ImGuiWindowFlags_NoNav;

    ImGui::SetNextWindowViewport(viewport->ID);
    ImGui::SetNextWindowPos(
        ImVec2(viewport->WorkPos.x + viewport->WorkSize.x - 18.0f, viewport->WorkPos.y + 42.0f),
        ImGuiCond_Always,
        ImVec2(1.0f, 0.0f));
    ImGui::SetNextWindowBgAlpha(0.9f);
    if (!ImGui::Begin("XCUI Hosted Preview HUD", nullptr, windowFlags)) {
        ImGui::End();
        return;
    }

    ImGui::TextUnformatted("XCUI Hosted Preview");
    ImGui::Text(
        "Registry %zu | surfaces %zu/%zu ready | last native drain %zu rendered, %zu skipped",
        m_hostedPreviewSurfaceRegistry.GetDescriptors().size(),
        readySurfaceCount,
        allocatedSurfaceCount,
        drainStats.renderedFrameCount,
        drainStats.skippedFrameCount);
    ImGui::Separator();

    const auto drawPanelRow = [](const HostedPreviewPanelDiagnostics& diagnostics) {
        const char* const pathLabel =
            GetHostedPreviewPathLabel(diagnostics.nativeRequested, diagnostics.nativePresenterBound);
        const char* const stateLabel = GetHostedPreviewStateLabel(
            diagnostics.hostedPreviewEnabled,
            diagnostics.nativePresenterBound,
            diagnostics.presentedThisFrame,
            diagnostics.queuedToNativePassThisFrame,
            diagnostics.surfaceImageAvailable,
            diagnostics.surfaceAllocated,
            diagnostics.surfaceReady,
            diagnostics.descriptorAvailable);

        ImGui::Text(
            "%s [%s] %s",
            diagnostics.debugName.c_str(),
            diagnostics.visible ? "visible" : "hidden",
            stateLabel);
        ImGui::TextDisabled("%s", pathLabel);
        ImGui::Text(
            "source %s | submit %zu lists / %zu cmds | flush %zu lists / %zu cmds",
            diagnostics.debugSource.empty() ? "n/a" : diagnostics.debugSource.c_str(),
            diagnostics.submittedDrawListCount,
            diagnostics.submittedCommandCount,
            diagnostics.flushedDrawListCount,
            diagnostics.flushedCommandCount);
        if (diagnostics.nativePresenterBound) {
            ImGui::Text(
                "surface %ux%u | logical %.0f x %.0f | descriptor %s | image %s | submit->native %s",
                diagnostics.surfaceWidth,
                diagnostics.surfaceHeight,
                diagnostics.logicalWidth,
                diagnostics.logicalHeight,
                diagnostics.descriptorAvailable ? "yes" : "no",
                diagnostics.surfaceImageAvailable ? "yes" : "no",
                diagnostics.queuedToNativePassThisFrame ? "yes" : "no");
        } else {
            ImGui::Text(
                "legacy present %s | cached native surface %s",
                diagnostics.presentedThisFrame ? "yes" : "no",
                (diagnostics.surfaceAllocated || diagnostics.surfaceImageAvailable) ? "retained" : "none");
        }
    };

    drawPanelRow(demoDiagnostics);
    ImGui::Separator();
    drawPanelRow(layoutLabDiagnostics);

    ImGui::End();
}

void Application::RenderQueuedHostedPreviews(
    const ::XCEngine::Rendering::RenderContext& renderContext,
    const ::XCEngine::Rendering::RenderSurface& surface) {
    (void)surface;
    ::XCEngine::Editor::XCUIBackend::XCUIHostedPreviewDrainStats drainStats = {};
    const auto& queuedFrames = m_hostedPreviewQueue.GetQueuedFrames();
    drainStats.queuedFrameCount = queuedFrames.size();
    for (const auto& queuedFrame : queuedFrames) {
        drainStats.queuedDrawListCount += queuedFrame.drawData.GetDrawListCount();
        drainStats.queuedCommandCount += queuedFrame.drawData.GetTotalCommandCount();
    }

    if (queuedFrames.empty()) {
        m_hostedPreviewQueue.SetLastDrainStats(drainStats);
        return;
    }

    m_hostedPreviewRenderBackend.SetTextAtlasProvider(&m_hostedPreviewTextAtlasProvider);
    std::size_t queuedFrameIndex = 0u;
    for (const auto& queuedFrame : queuedFrames) {
        m_hostedPreviewSurfaceRegistry.RecordQueuedFrame(queuedFrame, queuedFrameIndex);
        if (queuedFrame.debugName.empty()) {
            ++drainStats.skippedFrameCount;
            ++queuedFrameIndex;
            continue;
        }

        const std::uint32_t expectedWidth = queuedFrame.logicalSize.width > 1.0f
            ? static_cast<std::uint32_t>(std::ceil(queuedFrame.logicalSize.width))
            : 0u;
        const std::uint32_t expectedHeight = queuedFrame.logicalSize.height > 1.0f
            ? static_cast<std::uint32_t>(std::ceil(queuedFrame.logicalSize.height))
            : 0u;
        if (expectedWidth == 0u || expectedHeight == 0u) {
            ++drainStats.skippedFrameCount;
            ++queuedFrameIndex;
            continue;
        }

        HostedPreviewOffscreenSurface& previewSurface = FindOrAddHostedPreviewSurface(queuedFrame.debugName);
        if (!EnsureHostedPreviewSurface(previewSurface, expectedWidth, expectedHeight) ||
            !RenderHostedPreviewOffscreenSurface(previewSurface, renderContext, queuedFrame.drawData)) {
            ++drainStats.skippedFrameCount;
            ++queuedFrameIndex;
            continue;
        }

        ++drainStats.renderedFrameCount;
        const auto& overlayStats = m_hostedPreviewRenderBackend.GetLastOverlayStats();
        drainStats.renderedDrawListCount += overlayStats.drawListCount;
        drainStats.renderedCommandCount += overlayStats.renderedCommandCount;
        drainStats.skippedCommandCount += overlayStats.skippedCommandCount;
        m_hostedPreviewSurfaceRegistry.UpdateSurface(
            queuedFrame.debugName,
            previewSurface.textureRegistration.texture,
            ::XCEngine::UI::UIRect(
                0.0f,
                0.0f,
                static_cast<float>(previewSurface.width),
                static_cast<float>(previewSurface.height)));
        ++queuedFrameIndex;
    }

    m_hostedPreviewQueue.SetLastDrainStats(drainStats);
}

void Application::Frame() {
    if (!m_renderReady || !m_windowRenderer.BeginFrame()) {
        m_xcuiInputSource.ClearFrameTransients();
        return;
    }

    m_hostedPreviewQueue.BeginFrame();
    m_hostedPreviewSurfaceRegistry.BeginFrame();
    SyncHostedPreviewSurfaces();
    if (m_windowCompositor == nullptr) {
        m_xcuiInputSource.ClearFrameTransients();
        return;
    }

    m_windowCompositor->RenderFrame(
        kClearColor,
        [this]() {
            DispatchShellShortcuts();
            RenderShellChrome();
            if (m_demoPanel) {
                m_demoPanel->RenderIfVisible();
            }
            if (m_layoutLabPanel) {
                m_layoutLabPanel->RenderIfVisible();
            }
            bool showImGuiDemoWindow = IsShellViewToggleEnabled(ShellViewToggleId::ImGuiDemoWindow);
            if (showImGuiDemoWindow) {
                ImGui::ShowDemoWindow(&showImGuiDemoWindow);
                SetShellViewToggleEnabled(ShellViewToggleId::ImGuiDemoWindow, showImGuiDemoWindow);
            }

            SyncShellChromePanelStateFromPanels();
            SyncHostedPreviewSurfaces();
        },
        [this](
            const ::XCEngine::Rendering::RenderContext& renderContext,
            const ::XCEngine::Rendering::RenderSurface& surface) {
            RenderQueuedHostedPreviews(renderContext, surface);

            if (!IsShellViewToggleEnabled(ShellViewToggleId::NativeBackdrop) &&
                !IsShellViewToggleEnabled(ShellViewToggleId::NativeXCUIOverlay)) {
                return;
            }

            MainWindowNativeBackdropRenderer::FrameState frameState = {};
            frameState.elapsedSeconds = static_cast<float>(
                std::chrono::duration<double>(std::chrono::steady_clock::now() - m_startTime).count());
            frameState.pulseAccent = IsShellViewToggleEnabled(ShellViewToggleId::PulseAccent);
            frameState.drawBackdrop = IsShellViewToggleEnabled(ShellViewToggleId::NativeBackdrop);
            if (IsShellViewToggleEnabled(ShellViewToggleId::NativeXCUIOverlay)) {
                const float width = static_cast<float>(surface.GetWidth());
                const float height = static_cast<float>(surface.GetHeight());
                const float horizontalMargin = (std::min)(width * 0.14f, 128.0f);
                const float topMargin = (std::min)(height * 0.15f, 132.0f);
                const float bottomMargin = (std::min)(height * 0.12f, 96.0f);

                ::XCEngine::Editor::XCUIBackend::XCUILayoutLabInputState overlayInput = {};
                overlayInput.canvasRect = ::XCEngine::UI::UIRect(
                    horizontalMargin,
                    topMargin,
                    (std::max)(0.0f, width - horizontalMargin * 2.0f),
                    (std::max)(0.0f, height - topMargin - bottomMargin));
                overlayInput.pointerPosition = m_xcuiInputSource.GetPointerPosition();
                overlayInput.pointerInside =
                    overlayInput.pointerPosition.x >= overlayInput.canvasRect.x &&
                    overlayInput.pointerPosition.y >= overlayInput.canvasRect.y &&
                    overlayInput.pointerPosition.x <= overlayInput.canvasRect.x + overlayInput.canvasRect.width &&
                    overlayInput.pointerPosition.y <= overlayInput.canvasRect.y + overlayInput.canvasRect.height;
                const auto& overlayFrame = m_nativeOverlayRuntime.Update(overlayInput);
                frameState.overlayDrawData = &overlayFrame.drawData;
            }
            m_nativeBackdropRenderer.Render(renderContext, surface, frameState);
        });

    m_xcuiInputSource.ClearFrameTransients();
}

} // namespace NewEditor
} // namespace XCEngine