/*

 * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>

 *

 * SPDX-License-Identifier: BSD-2-Clause

 */

#pragma once

#include <AK/Vector.h>

#include <LibGfx/Matrix4x4.h>

#include <LibWeb/Painting/InlinePaintable.h>

#include <LibWeb/Painting/Paintable.h>

namespace Web::Painting {

class StackingContext {

    friend class ViewportPaintable;

public:

    StackingContext(Paintable&, StackingContext* parent, size_t index_in_tree_order);

    StackingContext* parent() { return m_parent; }

    StackingContext const* parent() const { return m_parent; }

    Paintable const& paintable() const { return *m_paintable; }

    PaintableBox const& paintable_box() const { return verify_cast<PaintableBox>(*m_paintable); }

    InlinePaintable const& inline_paintable() const { return verify_cast<InlinePaintable>(*m_paintable); }

    enum class StackingContextPaintPhase {

        BackgroundAndBorders,

        Floats,

        BackgroundAndBordersForInlineLevelAndReplaced,

        Foreground,

        FocusAndOverlay,

    };

    static void paint_node_as_stacking_context(Paintable const&, PaintContext&);

    static void paint_descendants(PaintContext&, Paintable const&, StackingContextPaintPhase);

    void paint(PaintContext&) const;

    [[nodiscard]] TraversalDecision hit_test(CSSPixelPoint, HitTestType, Function<TraversalDecision(HitTestResult)> const& callback) const;

    Gfx::AffineTransform affine_transform_matrix() const;

    void dump(int indent = 0) const;

    void sort();

    void set_last_paint_generation_id(u64 generation_id);

private:

    JS::NonnullGCPtr<Paintable> m_paintable;

    StackingContext* const m_parent { nullptr };

    Vector<StackingContext*> m_children;

    size_t m_index_in_tree_order { 0 };

    Optional<u64> m_last_paint_generation_id;

    Vector<JS::NonnullGCPtr<Paintable const>> m_positioned_descendants_with_stack_level_0_and_stacking_contexts;

    Vector<JS::NonnullGCPtr<Paintable const>> m_non_positioned_floating_descendants;

    static void paint_child(PaintContext&, StackingContext const&);

    void paint_internal(PaintContext&) const;

};

}