PalUIExtension/Api/WidgetLayoutLibrary.hpp

#pragma once

#include <optional>

#include <Reflection/UnrealObjectRef.hpp>

#include "UmgTypes.hpp"
#include "UnrealWrapper.hpp"
#include "PanelSlot.hpp"
#include "CanvasPanelSlot.hpp"

namespace PalUIExtension::Api
{
  
    class WidgetLayoutLibrary : public UnrealWrapper
    {
    public:
        static auto ClassPath() -> const TCHAR* { return STR("/Script/UMG.WidgetLayoutLibrary"); }
        static auto CDOPath()   -> const TCHAR* { return STR("/Script/UMG.Default__WidgetLayoutLibrary"); }
        static auto DebugTag()  -> const TCHAR* { return STR("WidgetLayoutLibrary"); }

        static auto Instance() -> WidgetLayoutLibrary&
        {
            static WidgetLayoutLibrary Singleton{};
            return Singleton;
        }

        // ---- slot casts ---------------------------------------------------

        auto SlotAsCanvasSlot(UObject* Widget) -> CanvasPanelSlot
        {
            return GetSingleton<CanvasPanelSlot>(STR("SlotAsCanvasSlot"), Widget);
        }
        auto SlotAsWrapBoxSlot(UObject* Widget)        -> PanelSlot { return GetSingleton<PanelSlot>(STR("SlotAsWrapBoxSlot"), Widget); }
        auto SlotAsWidgetSwitcherSlot(UObject* Widget) -> PanelSlot { return GetSingleton<PanelSlot>(STR("SlotAsWidgetSwitcherSlot"), Widget); }
        auto SlotAsVerticalBoxSlot(UObject* Widget)    -> PanelSlot { return GetSingleton<PanelSlot>(STR("SlotAsVerticalBoxSlot"), Widget); }
        auto SlotAsUniformGridSlot(UObject* Widget)    -> PanelSlot { return GetSingleton<PanelSlot>(STR("SlotAsUniformGridSlot"), Widget); }
        auto SlotAsSizeBoxSlot(UObject* Widget)        -> PanelSlot { return GetSingleton<PanelSlot>(STR("SlotAsSizeBoxSlot"), Widget); }
        auto SlotAsScrollBoxSlot(UObject* Widget)      -> PanelSlot { return GetSingleton<PanelSlot>(STR("SlotAsScrollBoxSlot"), Widget); }
        auto SlotAsScaleBoxSlot(UObject* Widget)       -> PanelSlot { return GetSingleton<PanelSlot>(STR("SlotAsScaleBoxSlot"), Widget); }
        auto SlotAsSafeBoxSlot(UObject* Widget)        -> PanelSlot { return GetSingleton<PanelSlot>(STR("SlotAsSafeBoxSlot"), Widget); }
        auto SlotAsOverlaySlot(UObject* Widget)        -> PanelSlot { return GetSingleton<PanelSlot>(STR("SlotAsOverlaySlot"), Widget); }
        auto SlotAsHorizontalBoxSlot(UObject* Widget)  -> PanelSlot { return GetSingleton<PanelSlot>(STR("SlotAsHorizontalBoxSlot"), Widget); }
        auto SlotAsGridSlot(UObject* Widget)           -> PanelSlot { return GetSingleton<PanelSlot>(STR("SlotAsGridSlot"), Widget); }
        auto SlotAsBorderSlot(UObject* Widget)         -> PanelSlot { return GetSingleton<PanelSlot>(STR("SlotAsBorderSlot"), Widget); }

        // ---- viewport / mouse ----------------------------------------------

        auto RemoveAllWidgets(UObject* WorldContextObject) -> bool
        {
            struct P { UObject* WorldContextObject; } p{ WorldContextObject };
            return Call(STR("RemoveAllWidgets"), p);
        }

        auto GetViewportSize(UObject* WorldContextObject) -> std::optional<FVector2D_>
        {
            struct P { UObject* WorldContextObject; FVector2D_ ReturnValue; } p{ WorldContextObject, {} };
            return CallForReturn(STR("GetViewportSize"), p, &P::ReturnValue);
        }
        auto GetViewportScale(UObject* WorldContextObject) -> std::optional<float>
        {
            struct P { UObject* WorldContextObject; float ReturnValue; } p{ WorldContextObject, 0.f };
            return CallForReturn(STR("GetViewportScale"), p, &P::ReturnValue);
        }
        auto GetMousePositionOnViewport(UObject* WorldContextObject) -> std::optional<FVector2D_>
        {
            struct P { UObject* WorldContextObject; FVector2D_ ReturnValue; } p{ WorldContextObject, {} };
            return CallForReturn(STR("GetMousePositionOnViewport"), p, &P::ReturnValue);
        }
        auto GetMousePositionOnPlatform() -> std::optional<FVector2D_>
        {
            return CallForReturn<FVector2D_>(STR("GetMousePositionOnPlatform"));
        }

        struct MousePositionDPI { float X{}; float Y{}; };
        auto GetMousePositionScaledByDPI(UObject* Player) -> std::optional<MousePositionDPI>
        {
            struct P { UObject* Player; float LocationX; float LocationY; bool ReturnValue; }
            p{ Player, 0.f, 0.f, false };
            if (!Call(STR("GetMousePositionScaledByDPI"), p) || !p.ReturnValue) return std::nullopt;
            return MousePositionDPI{ p.LocationX, p.LocationY };
        }

        auto ProjectWorldLocationToWidgetPosition(UObject* PlayerController, FVector_ WorldLocation, bool bPlayerViewportRelative) -> std::optional<FVector2D_>
        {
            struct P
            {
                UObject*   PlayerController;
                FVector_   WorldLocation;
                FVector2D_ ScreenPosition;
                bool       bPlayerViewportRelative;
                bool       ReturnValue;
            } p{ PlayerController, WorldLocation, {}, bPlayerViewportRelative, false };

            if (!Call(STR("ProjectWorldLocationToWidgetPosition"), p) || !p.ReturnValue) return std::nullopt;
            return p.ScreenPosition;
        }

    private:
        WidgetLayoutLibrary() : UnrealWrapper(ResolveCDO(), ClassOf<WidgetLayoutLibrary>(), DebugTag()) {}

        WidgetLayoutLibrary(const WidgetLayoutLibrary&) = delete;
        auto operator=(const WidgetLayoutLibrary&) -> WidgetLayoutLibrary& = delete;

        static auto ResolveCDO() -> UObject*
        {
            static Reflection::UnrealObjectRef Ref{ CDOPath(), DebugTag() };
            return Ref.Get();
        }

        auto CallStaticObjectGetter(const TCHAR* FunctionName, UObject* InObject) -> UObject*
        {
            struct P { UObject* InObject; UObject* ReturnValue; } p{ InObject, nullptr };
            auto Result = CallForReturn(FunctionName, p, &P::ReturnValue);
            return (Result && *Result) ? *Result : nullptr;
        }

        template <typename T>
        auto GetSingleton(const TCHAR* FunctionName, UObject* InObject) -> T
        {
            UObject* Obj = CallStaticObjectGetter(FunctionName, InObject);
            return Obj ? T{ Obj } : T{};
        }
    };
}