XCEngine/new_editor/src/XCUIBackend/NativeXCUIPanelCanvasHost.h

#pragma once

#include "XCUIBackend/XCUIPanelCanvasHost.h"

#include <algorithm>
#include <memory>
#include <string>
#include <utility>

namespace XCEngine {
namespace Editor {
namespace XCUIBackend {

namespace detail {

inline std::string CopyCanvasLabel(const char* text) {
    return text != nullptr ? std::string(text) : std::string();
}

inline ::XCEngine::UI::UIColor NativeCanvasPlaceholderFillColor() {
    return ::XCEngine::UI::UIColor(18.0f / 255.0f, 24.0f / 255.0f, 32.0f / 255.0f, 1.0f);
}

inline ::XCEngine::UI::UIColor NativeCanvasPlaceholderStrokeColor() {
    return ::XCEngine::UI::UIColor(54.0f / 255.0f, 72.0f / 255.0f, 94.0f / 255.0f, 1.0f);
}

inline ::XCEngine::UI::UIColor NativeCanvasPrimaryTextColor() {
    return ::XCEngine::UI::UIColor(191.0f / 255.0f, 205.0f / 255.0f, 224.0f / 255.0f, 1.0f);
}

inline ::XCEngine::UI::UIColor NativeCanvasSecondaryTextColor() {
    return ::XCEngine::UI::UIColor(132.0f / 255.0f, 147.0f / 255.0f, 170.0f / 255.0f, 1.0f);
}

inline XCUIPanelCanvasSession NormalizeNativeCanvasSession(
    const XCUIPanelCanvasRequest& request,
    const XCUIPanelCanvasSession* configuredSession) {
    if (configuredSession == nullptr) {
        return BuildPassiveXCUIPanelCanvasSession(request);
    }

    XCUIPanelCanvasSession session = *configuredSession;
    const float fallbackHostHeight = request.height > 0.0f ? request.height : 0.0f;
    if (session.hostRect.height <= 0.0f && fallbackHostHeight > 0.0f) {
        session.hostRect.height = fallbackHostHeight;
    }

    if (session.canvasRect.width <= 0.0f || session.canvasRect.height <= 0.0f) {
        const float topInset = request.topInset > 0.0f ? request.topInset : 0.0f;
        const float clampedTopInset =
            session.hostRect.height > 0.0f
            ? (std::min)(topInset, session.hostRect.height)
            : 0.0f;
        session.canvasRect = ::XCEngine::UI::UIRect(
            session.hostRect.x,
            session.hostRect.y + clampedTopInset,
            session.hostRect.width,
            (std::max)(0.0f, session.hostRect.height - clampedTopInset));
    }

    session.validCanvas =
        session.canvasRect.width > 1.0f &&
        session.canvasRect.height > 1.0f;
    if (!session.validCanvas) {
        session.hovered = false;
    }
    return session;
}

inline void RecordPlaceholder(
    ::XCEngine::UI::UIDrawList& drawList,
    const ::XCEngine::UI::UIRect& rect,
    const std::string& title,
    const std::string& subtitle) {
    if (rect.width <= 1.0f || rect.height <= 1.0f) {
        return;
    }

    drawList.AddFilledRect(rect, NativeCanvasPlaceholderFillColor(), 8.0f);
    drawList.AddRectOutline(rect, NativeCanvasPlaceholderStrokeColor(), 1.0f, 8.0f);
    if (!title.empty()) {
        drawList.AddText(
            ::XCEngine::UI::UIPoint(rect.x + 14.0f, rect.y + 14.0f),
            title,
            NativeCanvasPrimaryTextColor());
    }
    if (!subtitle.empty()) {
        drawList.AddText(
            ::XCEngine::UI::UIPoint(rect.x + 14.0f, rect.y + 36.0f),
            subtitle,
            NativeCanvasSecondaryTextColor());
    }
}

inline void RecordBadge(
    ::XCEngine::UI::UIDrawList& drawList,
    const ::XCEngine::UI::UIRect& canvasRect,
    const std::string& title,
    const std::string& subtitle) {
    if (title.empty()) {
        return;
    }

    const ::XCEngine::UI::UIRect badgeRect(
        canvasRect.x + 10.0f,
        canvasRect.y + 10.0f,
        290.0f,
        42.0f);
    drawList.AddFilledRect(
        badgeRect,
        ::XCEngine::UI::UIColor(16.0f / 255.0f, 22.0f / 255.0f, 30.0f / 255.0f, 216.0f / 255.0f),
        8.0f);
    drawList.AddRectOutline(badgeRect, NativeCanvasPlaceholderStrokeColor(), 1.0f, 8.0f);
    drawList.AddText(
        ::XCEngine::UI::UIPoint(badgeRect.x + 10.0f, badgeRect.y + 8.0f),
        title,
        NativeCanvasPrimaryTextColor());
    if (!subtitle.empty()) {
        drawList.AddText(
            ::XCEngine::UI::UIPoint(badgeRect.x + 10.0f, badgeRect.y + 24.0f),
            subtitle,
            NativeCanvasSecondaryTextColor());
    }
}

} // namespace detail

class NativeXCUIPanelCanvasHost final : public IXCUIPanelCanvasHost {
public:
    const char* GetDebugName() const override {
        return "NativeXCUIPanelCanvasHost";
    }

    void SetCanvasSession(const XCUIPanelCanvasSession& session) {
        m_configuredSession = session;
        m_hasConfiguredSession = true;
    }

    void ClearCanvasSession() {
        m_configuredSession = {};
        m_hasConfiguredSession = false;
    }

    bool HasConfiguredSession() const {
        return m_hasConfiguredSession;
    }

    const XCUIPanelCanvasSession& GetConfiguredSession() const {
        return m_configuredSession;
    }

    XCUIPanelCanvasSession BeginCanvas(const XCUIPanelCanvasRequest& request) override {
        m_currentFrame = {};
        m_currentFrame.childId = ResolveXCUIPanelCanvasChildId(request, "NativeXCUIPanelCanvasHost");
        m_currentFrame.session = detail::NormalizeNativeCanvasSession(
            request,
            m_hasConfiguredSession ? &m_configuredSession : nullptr);
        m_currentFrame.bordered = request.bordered;
        m_currentFrame.drawPreviewFrame = request.drawPreviewFrame;
        m_currentFrame.showingSurfaceImage = request.showSurfaceImage && request.surfaceImage.IsValid();
        m_currentFrame.placeholderTitle = detail::CopyCanvasLabel(request.placeholderTitle);
        m_currentFrame.placeholderSubtitle = detail::CopyCanvasLabel(request.placeholderSubtitle);
        m_currentFrame.badgeTitle = detail::CopyCanvasLabel(request.badgeTitle);
        m_currentFrame.badgeSubtitle = detail::CopyCanvasLabel(request.badgeSubtitle);
        m_currentFrame.surfaceImage = request.surfaceImage;

        m_overlayDrawList = nullptr;
        m_clipDepth = 0u;

        if (m_currentFrame.session.validCanvas) {
            const bool shouldRecordPlaceholder =
                !m_currentFrame.showingSurfaceImage &&
                (!m_currentFrame.placeholderTitle.empty() || !m_currentFrame.placeholderSubtitle.empty());
            if (shouldRecordPlaceholder) {
                ::XCEngine::UI::UIDrawList& drawList = EnsureOverlayDrawList();
                detail::RecordPlaceholder(
                    drawList,
                    m_currentFrame.session.canvasRect,
                    m_currentFrame.placeholderTitle,
                    m_currentFrame.placeholderSubtitle);
            }

            if (m_currentFrame.showingSurfaceImage) {
                EnsureOverlayDrawList().AddImage(
                    m_currentFrame.session.canvasRect,
                    m_currentFrame.surfaceImage.texture,
                    ::XCEngine::UI::UIColor(1.0f, 1.0f, 1.0f, 1.0f),
                    m_currentFrame.surfaceImage.uvMin,
                    m_currentFrame.surfaceImage.uvMax);
            }

            if (request.drawPreviewFrame) {
                DrawOutlineRect(
                    m_currentFrame.session.canvasRect,
                    detail::NativeCanvasPlaceholderStrokeColor(),
                    1.0f,
                    8.0f);
            }

            if (!m_currentFrame.badgeTitle.empty()) {
                ::XCEngine::UI::UIDrawList& drawList = EnsureOverlayDrawList();
                detail::RecordBadge(
                    drawList,
                    m_currentFrame.session.canvasRect,
                    m_currentFrame.badgeTitle,
                    m_currentFrame.badgeSubtitle);
            }
        }

        return m_currentFrame.session;
    }

    void DrawFilledRect(
        const ::XCEngine::UI::UIRect& rect,
        const ::XCEngine::UI::UIColor& color,
        float rounding = 0.0f) override {
        if (rect.width <= 0.0f || rect.height <= 0.0f) {
            return;
        }

        EnsureOverlayDrawList().AddFilledRect(rect, color, rounding);
    }

    void DrawOutlineRect(
        const ::XCEngine::UI::UIRect& rect,
        const ::XCEngine::UI::UIColor& color,
        float thickness = 1.0f,
        float rounding = 0.0f) override {
        if (rect.width <= 0.0f || rect.height <= 0.0f) {
            return;
        }

        EnsureOverlayDrawList().AddRectOutline(rect, color, thickness, rounding);
    }

    void DrawText(
        const ::XCEngine::UI::UIPoint& position,
        std::string_view text,
        const ::XCEngine::UI::UIColor& color,
        float fontSize = 0.0f) override {
        if (text.empty()) {
            return;
        }

        EnsureOverlayDrawList().AddText(position, std::string(text), color, fontSize);
    }

    void EndCanvas() override {
        if (m_overlayDrawList != nullptr) {
            while (m_clipDepth > 0u) {
                m_overlayDrawList->PopClipRect();
                --m_clipDepth;
            }
        }

        m_overlayDrawList = nullptr;
    }

    bool TryGetLatestFrameSnapshot(XCUIPanelCanvasFrameSnapshot& outSnapshot) const override {
        outSnapshot = m_currentFrame;
        return !outSnapshot.childId.empty();
    }

private:
    ::XCEngine::UI::UIDrawList& EnsureOverlayDrawList() {
        if (m_overlayDrawList == nullptr) {
            ::XCEngine::UI::UIDrawList& drawList =
                m_currentFrame.overlayDrawData.EmplaceDrawList(m_currentFrame.childId + ".overlay");
            drawList.PushClipRect(m_currentFrame.session.canvasRect, true);
            m_overlayDrawList = &drawList;
            m_clipDepth = 1u;
        }

        return *m_overlayDrawList;
    }

    bool m_hasConfiguredSession = false;
    XCUIPanelCanvasSession m_configuredSession = {};
    XCUIPanelCanvasFrameSnapshot m_currentFrame = {};
    ::XCEngine::UI::UIDrawList* m_overlayDrawList = nullptr;
    std::size_t m_clipDepth = 0u;
};

inline std::unique_ptr<IXCUIPanelCanvasHost> CreateNativeXCUIPanelCanvasHost() {
    return std::make_unique<NativeXCUIPanelCanvasHost>();
}

} // namespace XCUIBackend
} // namespace Editor
} // namespace XCEngine