/*
 * Copyright (c) 2024, Matthew Olsson <mattco@serenityos.org>.
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <LibWeb/Animations/KeyframeEffect.h>
#include <LibWeb/Bindings/CSSAnimationPrototype.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/CSS/CSSAnimation.h>
#include <LibWeb/DOM/Element.h>

namespace Web::CSS {

GC_DEFINE_ALLOCATOR(CSSAnimation);

GC::Ref<CSSAnimation> CSSAnimation::create(JS::Realm& realm)
{
    return realm.create<CSSAnimation>(realm);
}

// https://www.w3.org/TR/css-animations-2/#animation-composite-order
Optional<int> CSSAnimation::class_specific_composite_order(GC::Ref<Animations::Animation> other_animation) const
{
    auto other = GC::Ref { as<CSSAnimation>(*other_animation) };

    // The existence of an owning element determines the animation class, so both animations should have their owning
    // element in the same state
    VERIFY(!owning_element() == !other->owning_element());

    // Within the set of CSS Animations with an owning element, two animations A and B are sorted in composite order
    // (first to last) as follows:
    if (owning_element()) {
        // 1. If the owning element of A and B differs, sort A and B by tree order of their corresponding owning elements.
        //    With regard to pseudo-elements, the sort order is as follows:
        //    - element
        //    - ::marker
        //    - ::before
        //    - any other pseudo-elements not mentioned specifically in this list, sorted in ascending order by the Unicode
        //      codepoints that make up each selector
        //    - ::after
        //    - element children
        if (owning_element().ptr() != other->owning_element().ptr()) {
            // FIXME: Sort by tree order
            return {};
        }

        // 2. Otherwise, sort A and B based on their position in the computed value of the animation-name property of the
        //    (common) owning element.
        // FIXME: Do this when animation-name supports multiple values
        return {};
    }

    // The composite order of CSS Animations without an owning element is based on their position in the global animation list.
    return global_animation_list_order() - other->global_animation_list_order();
}

Animations::AnimationClass CSSAnimation::animation_class() const
{
    if (owning_element())
        return Animations::AnimationClass::CSSAnimationWithOwningElement;
    return Animations::AnimationClass::CSSAnimationWithoutOwningElement;
}

CSSAnimation::CSSAnimation(JS::Realm& realm)
    : Animations::Animation(realm)
{
    // FIXME:
    // CSS Animations generated using the markup defined in this specification are not added to the global animation
    // list when they are created. Instead, these animations are appended to the global animation list at the first
    // moment when they transition out of the idle play state after being disassociated from their owning element. CSS
    // Animations that have been disassociated from their owning element but are still idle do not have a defined
    // composite order.
}

void CSSAnimation::initialize(JS::Realm& realm)
{
    WEB_SET_PROTOTYPE_FOR_INTERFACE(CSSAnimation);
    Base::initialize(realm);
}

}
