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 * Copyright (C) 2025 Apple Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions
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 * 1. Redistributions of source code must retain the above copyright
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 */

#pragma once

#include <WebCore/BoxSides.h>
#include <WebCore/LayoutRange.h>
#include <WebCore/RenderBox.h>
#include <WebCore/StyleInset.h>
#include <WebCore/StyleMargin.h>
#include <WebCore/StyleSelfAlignmentData.h>

namespace WebCore {

class PositionedLayoutConstraints {
public:
    PositionedLayoutConstraints(const RenderBox&, LogicalBoxAxis selfAxis);
    PositionedLayoutConstraints(const RenderBox&, const RenderStyle& selfStyleOverride, LogicalBoxAxis selfAxis);
    void computeInsets();

    /*** The following are available without calling computeInsets(). ***/

    const RenderBoxModelObject& container() const { return *m_container; }
    LayoutUnit containingSize() const { return m_containingRange.size(); }
    LayoutUnit containingInlineSize() const { return m_containingInlineSize; }
    LayoutRange containingRange() const { return m_containingRange; }
    LayoutRange originalContainingRange() const { return m_originalContainingRange; }
    LayoutRange extractRange(LayoutRect);

    BoxAxis physicalAxis() const { return m_physicalAxis; }
    LogicalBoxAxis containingAxis() const { return m_containingAxis; }
    WritingMode containingWritingMode() const { return m_containingWritingMode; }
    WritingMode selfWritingMode() const { return m_writingMode; }

    bool needsAnchor() const;
    const RenderBoxModelObject* defaultAnchorBox() const { return m_defaultAnchorBox.get(); }
    const StyleSelfAlignmentData& alignment() const { return m_alignment; }
    ItemPosition resolveAlignmentValue() const; // Convert auto/normal as necessary.
    bool alignmentAppliesStretch(ItemPosition normalAlignment) const;

    bool isOrthogonal() const { return m_containingWritingMode.isOrthogonal(m_writingMode); }
    inline bool isOpposing() const;
    bool isBlockOpposing() const { return m_containingWritingMode.isBlockOpposing(m_writingMode); }
    bool isBlockFlipped() const { return m_containingWritingMode.isBlockFlipped(); }
    bool startIsBefore() const { return m_containingAxis == LogicalBoxAxis::Block || m_containingWritingMode.isLogicalLeftInlineStart(); }

    /*** For everything else, you MUST call computeInsets() after the constructor. ***/

    // Before = logical top or left wrt containing block (i.e. the lower-coordinate side).
    // After = logical bottom or right wrt containing block (i.e. the higher-coordinate side).
    LayoutUnit bordersPlusPadding() const { return m_bordersPlusPadding; }
    Style::MarginEdge marginBefore() const { return m_marginBefore; }
    Style::MarginEdge marginAfter() const { return m_marginAfter; }
    Style::InsetEdge insetBefore() const { return m_insetBefore; }
    Style::InsetEdge insetAfter() const { return m_insetAfter; }
    LayoutUnit marginBeforeValue() const { return Style::evaluateMinimum(m_marginBefore, m_containingInlineSize, 1.0f /* FIXME ZOOM EFFECTED? */); }
    LayoutUnit marginAfterValue() const { return Style::evaluateMinimum(m_marginAfter, m_containingInlineSize, 1.0f /* FIXME ZOOM EFFECTED? */); }
    LayoutUnit insetBeforeValue() const { return Style::evaluateMinimum(m_insetBefore, containingSize(), 1.0f /* FIXME ZOOM EFFECTED? */); }
    LayoutUnit insetAfterValue() const { return Style::evaluateMinimum(m_insetAfter, containingSize(), 1.0f /* FIXME ZOOM EFFECTED? */); }

    LayoutUnit insetModifiedContainingSize() const { return m_insetModifiedContainingRange.size(); }
    LayoutRange insetModifiedContainingRange() const { return m_insetModifiedContainingRange; }
    LayoutUnit availableContentSpace() const { return insetModifiedContainingSize() - marginBeforeValue() - bordersPlusPadding() - marginAfterValue(); } // This may be negative.

    void resolvePosition(RenderBox::LogicalExtentComputedValues&) const;
    LayoutUnit resolveAlignmentShift(const LayoutUnit unusedSpace, const LayoutUnit itemSize) const;

    void fixupLogicalLeftPosition(RenderBox::LogicalExtentComputedValues&) const;
    void adjustLogicalTopWithLogicalHeightIfNeeded(RenderBox::LogicalExtentComputedValues&) const;

private:
    bool containingCoordsAreFlipped() const;

    void captureInsets();
    void captureGridArea();
    void captureAnchorGeometry();
    LayoutRange adjustForPositionArea(const LayoutRange rangeToAdjust, const LayoutRange anchorArea, const BoxAxis containerAxis);

    bool needsGridAreaAdjustmentBeforeStaticPositioning() const;
    bool isEligibleForStaticRangeAlignment(LayoutUnit spaceInStaticRange, LayoutUnit itemSize) const;
    void computeStaticPosition();
    void computeInlineStaticDistance();
    void computeBlockStaticDistance();

    CheckedRef<const RenderBox> m_renderer;
    CheckedPtr<const RenderBoxModelObject> m_container;
    const WritingMode m_containingWritingMode;
    const WritingMode m_writingMode;
    const LogicalBoxAxis m_selfAxis;
    const LogicalBoxAxis m_containingAxis;
    const BoxAxis m_physicalAxis;
    const RenderStyle& m_style;
    StyleSelfAlignmentData m_alignment;
    const CheckedPtr<const RenderBoxModelObject> m_defaultAnchorBox; // Only set if needed.

    LayoutRange m_anchorArea; // Only valid if defaultAnchor exists.
    LayoutRange m_containingRange;
    LayoutRange m_originalContainingRange;
    LayoutRange m_insetModifiedContainingRange;
    LayoutUnit m_containingInlineSize;

    LayoutUnit m_bordersPlusPadding;
    Style::MarginEdge m_marginBefore;
    Style::MarginEdge m_marginAfter;
    Style::InsetEdge m_insetBefore;
    Style::InsetEdge m_insetAfter;
    bool m_useStaticPosition { false };
#if ASSERT_ENABLED
    mutable bool m_isEligibleForStaticRangeAlignment { false };
#endif
};

inline bool PositionedLayoutConstraints::isOpposing() const
{
    return m_containingAxis == LogicalBoxAxis::Inline
        ? m_containingWritingMode.isInlineOpposing(m_writingMode)
        : m_containingWritingMode.isBlockOpposing(m_writingMode);

}

}
