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#pragma once
#include "Qt3DSRender.h"
#include "foundation/Qt3DSVec2.h"
#include "render/Qt3DSRenderBaseTypes.h"
#include "Qt3DSRenderCamera.h"
#include "Qt3DSRenderContextCore.h"

namespace qt3ds {
namespace render {

    /**	An independent, testable entity to encapsulate taking at least:
     *  layer, current viewport rect, current scissor rect, presentation design dimensions
     *	and producing a set of rectangles:
     *	layer viewport rect (inside viewport rect and calculated using outer viewport rect info)
     *	layer scissor rect (inside current scissor rect)
     *	layer camera rect (may be the viewport rect)
     *
     *  In the case where we have to render offscreen for this layer then we need to handle produce
     *	a set of texture dimensions and the layer camera rect ends up being same size but with no
     *offsets.
     *
     *  This object should handle part of any translation from screenspace to global space.
     *	I am using language level access control on this object because it needs specific
     *	interface design that will enable future modifications.
     */
    struct SLayerRenderHelper
    {
    private:
        NVRenderRectF m_PresentationViewport;
        NVRenderRectF m_PresentationScissor;
        QT3DSVec2 m_PresentationDesignDimensions;
        SLayer *m_Layer;
        SCamera *m_Camera;
        SCamera m_CameraLeftEye;
        SCamera m_CameraRightEye;
        bool m_Offscreen;

        NVRenderRectF m_originalViewport;
        NVRenderRectF m_Viewport;
        NVRenderRectF m_Scissor;

        ScaleModes::Enum m_ScaleMode;

        StereoModes::Enum m_StereoMode = StereoModes::Mono;
        StereoViews::Enum m_StereoView = StereoViews::Mono;
        QT3DSF32 m_StereoEyeSeparation = 0.4f;

        QT3DSVec2 m_ScaleFactor;

    public:
        SLayerRenderHelper();

        SLayerRenderHelper(const NVRenderRectF &inPresentationViewport,
                           const NVRenderRectF &inPresentationScissor,
                           const QT3DSVec2 &inPresentationDesignDimensions, SLayer &inLayer,
                           bool inOffscreen, qt3ds::render::ScaleModes::Enum inScaleMode,
                           qt3ds::render::StereoModes::Enum inStereoMode,
                           qt3ds::render::StereoViews::Enum inStereoView,
                           double inStereoEyeSeparation,
                           qt3ds::QT3DSVec2 inScaleFactor);

        NVRenderRectF GetPresentationViewport() const { return m_PresentationViewport; }
        NVRenderRectF GetPresentationScissor() const { return m_PresentationScissor; }
        QT3DSVec2 GetPresentationDesignDimensions() const { return m_PresentationDesignDimensions; }
        SLayer *GetLayer() const { return m_Layer; }
        // Return currently used camera
        SCamera *GetCamera();
        bool IsOffscreen() const { return m_Offscreen; }

        bool isStereoscopic() const;
        // Get/set current stereo mode. Default mode is Mono (no stereo)
        StereoModes::Enum getStereoMode() const { return m_StereoMode; }
        void setStereoMode(StereoModes::Enum mode) { m_StereoMode = mode; }
        // Get/set eye (camera) separation.
        QT3DSF32 getEyeSeparation() const { return m_StereoEyeSeparation; }
        void setEyeSeparation(QT3DSF32 separation) { m_StereoEyeSeparation = separation; }

        void setViewport(const NVRenderRectF &viewport);
        // Does not differ whether offscreen or not, simply states how this layer maps to the
        // presentation
        NVRenderRectF getOriginalLayerToPresentationViewport() const;
        NVRenderRectF GetLayerToPresentationViewport(bool noStereo = false) const;
        // Does not differ whether offscreen or not, scissor rect of how this layer maps to
        // presentation.
        NVRenderRectF GetLayerToPresentationScissorRect(bool noStereo = false) const;

        QSize GetTextureDimensions() const;

        SCameraGlobalCalculationResult SetupCameraForRender(SCamera &inCamera);

        Option<QT3DSVec2> GetLayerMouseCoords(const QT3DSVec2 &inMouseCoords,
                                           const QT3DSVec2 &inWindowDimensions,
                                           bool inForceIntersect) const;

        Option<SRay> GetPickRay(const QT3DSVec2 &inMouseCoords, const QT3DSVec2 &inWindowDimensions,
                                bool inForceIntersect, bool sceneCameraView = false) const;

        // Checks the various viewports and determines if the layer is visible or not.
        bool IsLayerVisible() const;

    private:
        // Viewport used when actually rendering.  In the case where this is an offscreen item then
        // it may be
        // different than the layer to presentation viewport.
        NVRenderRectF GetLayerRenderViewport() const;

        void copyCameraProperties(SCamera *sourceCamera, SCamera *destinationCamera);
        void adjustCameraStereoSeparation();
    };
}
}