#include "D3D12WindowRenderLoop.h"

namespace XCEngine::UI::Editor::Host {

D3D12WindowRenderLoopAttachResult D3D12WindowRenderLoop::Attach(
    NativeRenderer& uiRenderer,
    D3D12WindowRenderer& windowRenderer) {
    m_uiRenderer = &uiRenderer;
    m_windowRenderer = &windowRenderer;

    D3D12WindowRenderLoopAttachResult result = {};
    result.hasViewportSurfacePresentation = m_uiRenderer->AttachWindowRenderer(*m_windowRenderer);
    if (!result.hasViewportSurfacePresentation) {
        const std::string& interopError = m_uiRenderer->GetLastRenderError();
        result.interopWarning = interopError.empty()
            ? "native renderer d3d12 interop unavailable; falling back to hwnd renderer."
            : "native renderer d3d12 interop unavailable; falling back to hwnd renderer: " +
                interopError;
    }
    return result;
}

void D3D12WindowRenderLoop::Detach() {
    if (m_uiRenderer != nullptr) {
        m_uiRenderer->DetachWindowRenderer();
    }

    m_uiRenderer = nullptr;
    m_windowRenderer = nullptr;
}

D3D12WindowRenderLoopFrameContext D3D12WindowRenderLoop::BeginFrame() const {
    D3D12WindowRenderLoopFrameContext context = {};
    if (!HasViewportSurfacePresentation()) {
        return context;
    }

    if (!m_windowRenderer->BeginFrame()) {
        const std::string& frameError = m_windowRenderer->GetLastError();
        context.warning = frameError.empty()
            ? "d3d12 frame begin failed"
            : "d3d12 frame begin failed: " + frameError;
        return context;
    }

    context.canRenderViewports = true;
    context.renderContext = m_windowRenderer->GetRenderContext();
    return context;
}

D3D12WindowRenderLoopResizeResult D3D12WindowRenderLoop::ApplyResize(UINT width, UINT height) {
    D3D12WindowRenderLoopResizeResult result = {};
    if (m_uiRenderer == nullptr || m_windowRenderer == nullptr) {
        result.interopWarning = "window render loop is detached.";
        return result;
    }

    m_uiRenderer->Resize(width, height);
    const bool hadViewportSurfacePresentation = m_uiRenderer->HasAttachedWindowRenderer();
    if (hadViewportSurfacePresentation) {
        m_uiRenderer->ReleaseWindowRendererBackBufferTargets();
    }

    const bool resizedWindowRenderer =
        m_windowRenderer->Resize(static_cast<int>(width), static_cast<int>(height));
    if (!resizedWindowRenderer || !m_windowRenderer->GetLastError().empty()) {
        const std::string& resizeError = m_windowRenderer->GetLastError();
        result.windowRendererWarning = resizeError.empty()
            ? "window renderer resize warning."
            : "window renderer resize warning: " + resizeError;
    }

    if (!resizedWindowRenderer) {
        if (hadViewportSurfacePresentation) {
            result.hasViewportSurfacePresentation =
                m_uiRenderer->RebuildWindowRendererBackBufferTargets();
            if (!result.hasViewportSurfacePresentation) {
                const D3D12WindowRenderLoopAttachResult attachResult =
                    Attach(*m_uiRenderer, *m_windowRenderer);
                result.hasViewportSurfacePresentation = attachResult.hasViewportSurfacePresentation;
                result.interopWarning = attachResult.interopWarning;
            }
        }
        return result;
    }

    if (hadViewportSurfacePresentation) {
        result.hasViewportSurfacePresentation =
            m_uiRenderer->RebuildWindowRendererBackBufferTargets();
        if (!result.hasViewportSurfacePresentation) {
            const D3D12WindowRenderLoopAttachResult attachResult =
                Attach(*m_uiRenderer, *m_windowRenderer);
            result.hasViewportSurfacePresentation = attachResult.hasViewportSurfacePresentation;
            result.interopWarning = attachResult.interopWarning;
        }
        return result;
    }

    const D3D12WindowRenderLoopAttachResult attachResult =
        Attach(*m_uiRenderer, *m_windowRenderer);
    result.hasViewportSurfacePresentation = attachResult.hasViewportSurfacePresentation;
    result.interopWarning = attachResult.interopWarning;
    return result;
}

D3D12WindowRenderLoopPresentResult D3D12WindowRenderLoop::Present(
    const ::XCEngine::UI::UIDrawData& drawData) const {
    D3D12WindowRenderLoopPresentResult result = {};
    if (m_uiRenderer == nullptr) {
        result.warning = "window render loop has no ui renderer.";
        return result;
    }

    if (HasViewportSurfacePresentation()) {
        result.framePresented = m_uiRenderer->RenderToWindowRenderer(drawData);
        if (!result.framePresented) {
            const std::string& composeError = m_uiRenderer->GetLastRenderError();
            result.warning = composeError.empty()
                ? "d3d12 window composition failed, falling back to hwnd renderer."
                : "d3d12 window composition failed, falling back to hwnd renderer: " +
                    composeError;
        }
    }

    if (!result.framePresented) {
        result.framePresented = m_uiRenderer->Render(drawData);
        if (!result.framePresented && result.warning.empty()) {
            result.warning = m_uiRenderer->GetLastRenderError();
        }
    }

    return result;
}

bool D3D12WindowRenderLoop::HasViewportSurfacePresentation() const {
    return m_uiRenderer != nullptr &&
        m_windowRenderer != nullptr &&
        m_uiRenderer->HasAttachedWindowRenderer();
}

} // namespace XCEngine::UI::Editor::Host