/*

 * Copyright (c) 2023, Matthew Olsson <mattco@serenityos.org>.

 *

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

 */

#include <LibJS/Heap/Heap.h>

#include <LibJS/Runtime/Realm.h>

#include <LibWeb/Animations/DocumentTimeline.h>

#include <LibWeb/Bindings/DocumentTimelinePrototype.h>

#include <LibWeb/DOM/Document.h>

#include <LibWeb/HTML/Window.h>

#include <LibWeb/HighResolutionTime/Performance.h>

#include <LibWeb/WebIDL/ExceptionOr.h>

namespace Web::Animations {

JS_DEFINE_ALLOCATOR(DocumentTimeline);

JS::NonnullGCPtr<DocumentTimeline> DocumentTimeline::create(JS::Realm& realm, DOM::Document& document, HighResolutionTime::DOMHighResTimeStamp origin_time)

{

    auto timeline = realm.heap().allocate<DocumentTimeline>(realm, realm, document, origin_time);

    auto current_time = document.last_animation_frame_timestamp();

    if (!current_time.has_value()) {

        // The document hasn't processed an animation frame yet, so just use the exact current time

        auto* window_or_worker = dynamic_cast<HTML::WindowOrWorkerGlobalScopeMixin*>(&realm.global_object());

        VERIFY(window_or_worker);

        current_time = window_or_worker->performance()->now();

    }

    timeline->set_current_time(current_time);

    return timeline;

}

// https://www.w3.org/TR/web-animations-1/#dom-documenttimeline-documenttimeline

WebIDL::ExceptionOr<JS::NonnullGCPtr<DocumentTimeline>> DocumentTimeline::construct_impl(JS::Realm& realm, DocumentTimelineOptions options)

{

    // Creates a new DocumentTimeline. The Document with which the timeline is associated is the Document associated

    // with the Window that is the current global object.

    auto& window = verify_cast<HTML::Window>(realm.global_object());

    return create(realm, window.associated_document(), options.origin_time);

}

// https://www.w3.org/TR/web-animations-1/#ref-for-timeline-time-to-origin-relative-time

Optional<double> DocumentTimeline::convert_a_timeline_time_to_an_origin_relative_time(Optional<double> timeline_time)

{

    // To convert a timeline time, timeline time, to an origin-relative time for a document timeline, timeline, return

    // the sum of the timeline time and timeline’s origin time. If timeline is inactive, return an unresolved time

    // value.

    if (is_inactive() || !timeline_time.has_value())

        return {};

    return timeline_time.value() + m_origin_time;

}

// https://www.w3.org/TR/web-animations-1/#origin-time

void DocumentTimeline::set_current_time(Optional<double> current_time)

{

    // A document timeline is a type of timeline that is associated with a document and whose current time is calculated

    // as a fixed offset from the now timestamp provided each time the update animations and send events procedure is

    // run. This fixed offset is referred to as the document timeline’s origin time.

    if (!current_time.has_value())

        Base::set_current_time({});

    else

        Base::set_current_time(current_time.value() - m_origin_time);

    // After a document timeline becomes active, it is monotonically increasing.

    if (!is_inactive())

        VERIFY(is_monotonically_increasing());

}

// https://www.w3.org/TR/web-animations-1/#document-timelines

bool DocumentTimeline::is_inactive() const

{

    // A document timeline that is associated with a Document which is not an active document is also considered to be

    // inactive.

    return Base::is_inactive() || !associated_document()->is_active();

}

DocumentTimeline::DocumentTimeline(JS::Realm& realm, DOM::Document& document, HighResolutionTime::DOMHighResTimeStamp origin_time)

    : AnimationTimeline(realm)

    , m_origin_time(origin_time)

{

    set_associated_document(document);

}

void DocumentTimeline::initialize(JS::Realm& realm)

{

    Base::initialize(realm);

    WEB_SET_PROTOTYPE_FOR_INTERFACE(DocumentTimeline);

}

}