/*

 * Copyright (c) 2020, the SerenityOS developers.

 * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>

 *

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

 */

#include <LibWeb/Bindings/HTMLDetailsElementPrototype.h>

#include <LibWeb/Bindings/Intrinsics.h>

#include <LibWeb/DOM/ElementFactory.h>

#include <LibWeb/DOM/Event.h>

#include <LibWeb/DOM/ShadowRoot.h>

#include <LibWeb/DOM/Text.h>

#include <LibWeb/HTML/EventLoop/TaskQueue.h>

#include <LibWeb/HTML/HTMLDetailsElement.h>

#include <LibWeb/HTML/HTMLSlotElement.h>

#include <LibWeb/HTML/HTMLSummaryElement.h>

#include <LibWeb/HTML/ToggleEvent.h>

#include <LibWeb/Namespace.h>

namespace Web::HTML {

JS_DEFINE_ALLOCATOR(HTMLDetailsElement);

HTMLDetailsElement::HTMLDetailsElement(DOM::Document& document, DOM::QualifiedName qualified_name)

    : HTMLElement(document, move(qualified_name))

{

}

HTMLDetailsElement::~HTMLDetailsElement() = default;

void HTMLDetailsElement::visit_edges(Cell::Visitor& visitor)

{

    Base::visit_edges(visitor);

    visitor.visit(m_summary_slot);

    visitor.visit(m_descendants_slot);

}

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

{

    Base::initialize(realm);

    WEB_SET_PROTOTYPE_FOR_INTERFACE(HTMLDetailsElement);

}

void HTMLDetailsElement::inserted()

{

    create_shadow_tree_if_needed().release_value_but_fixme_should_propagate_errors();

    update_shadow_tree_slots();

}

void HTMLDetailsElement::removed_from(DOM::Node*)

{

    set_shadow_root(nullptr);

}

void HTMLDetailsElement::attribute_changed(FlyString const& name, Optional<String> const& old_value, Optional<String> const& value)

{

    Base::attribute_changed(name, old_value, value);

    // https://html.spec.whatwg.org/multipage/interactive-elements.html#details-notification-task-steps

    if (name == HTML::AttributeNames::open) {

        // 1. If the open attribute is added, queue a details toggle event task given the details element, "closed", and "open".

        if (value.has_value()) {

            queue_a_details_toggle_event_task("closed"_string, "open"_string);

        }

        // 2. Otherwise, queue a details toggle event task given the details element, "open", and "closed".

        else {

            queue_a_details_toggle_event_task("open"_string, "closed"_string);

        }

        update_shadow_tree_style();

    }

}

void HTMLDetailsElement::children_changed()

{

    Base::children_changed();

    update_shadow_tree_slots();

}

// https://html.spec.whatwg.org/multipage/interactive-elements.html#queue-a-details-toggle-event-task

void HTMLDetailsElement::queue_a_details_toggle_event_task(String old_state, String new_state)

{

    // 1. If element's details toggle task tracker is not null, then:

    if (m_details_toggle_task_tracker.has_value()) {

        // 1. Set oldState to element's details toggle task tracker's old state.

        old_state = move(m_details_toggle_task_tracker->old_state);

        // 2. Remove element's details toggle task tracker's task from its task queue.

        HTML::main_thread_event_loop().task_queue().remove_tasks_matching([&](auto const& task) {

            return task.id() == m_details_toggle_task_tracker->task_id;

        });

        // 3. Set element's details toggle task tracker to null.

        m_details_toggle_task_tracker->task_id = {};

    }

    // 2. Queue an element task given the DOM manipulation task source and element to run the following steps:

    auto task_id = queue_an_element_task(HTML::Task::Source::DOMManipulation, [this, old_state, new_state = move(new_state)]() mutable {

        // 1. Fire an event named toggle at element, using ToggleEvent, with the oldState attribute initialized to

        //    oldState and the newState attribute initialized to newState.

        ToggleEventInit event_init {};

        event_init.old_state = move(old_state);

        event_init.new_state = move(new_state);

        dispatch_event(ToggleEvent::create(realm(), HTML::EventNames::toggle, move(event_init)));

        // 2. Set element's details toggle task tracker to null.

        m_details_toggle_task_tracker = {};

    });

    // 3. Set element's details toggle task tracker to a struct with task set to the just-queued task and old state set to oldState.

    m_details_toggle_task_tracker = ToggleTaskTracker {

        .task_id = task_id,

        .old_state = move(old_state),

    };

}

// https://html.spec.whatwg.org/#the-details-and-summary-elements

WebIDL::ExceptionOr<void> HTMLDetailsElement::create_shadow_tree_if_needed()

{

    if (shadow_root())

        return {};

    auto& realm = this->realm();

    // The element is also expected to have an internal shadow tree with two slots.

    auto shadow_root = heap().allocate<DOM::ShadowRoot>(realm, document(), *this, Bindings::ShadowRootMode::Closed);

    shadow_root->set_slot_assignment(Bindings::SlotAssignmentMode::Manual);

    // The first slot is expected to take the details element's first summary element child, if any.

    auto summary_slot = TRY(DOM::create_element(document(), HTML::TagNames::slot, Namespace::HTML));

    MUST(shadow_root->append_child(summary_slot));

    // The second slot is expected to take the details element's remaining descendants, if any.

    auto descendants_slot = TRY(DOM::create_element(document(), HTML::TagNames::slot, Namespace::HTML));

    MUST(shadow_root->append_child(descendants_slot));

    m_summary_slot = static_cast<HTML::HTMLSlotElement&>(*summary_slot);

    m_descendants_slot = static_cast<HTML::HTMLSlotElement&>(*descendants_slot);

    set_shadow_root(shadow_root);

    return {};

}

void HTMLDetailsElement::update_shadow_tree_slots()

{

    if (!shadow_root())

        return;

    Vector<HTMLSlotElement::SlottableHandle> summary_assignment;

    Vector<HTMLSlotElement::SlottableHandle> descendants_assignment;

    auto* summary = first_child_of_type<HTMLSummaryElement>();

    if (summary != nullptr)

        summary_assignment.append(JS::make_handle(static_cast<DOM::Element&>(*summary)));

    for_each_in_subtree([&](auto& child) {

        if (&child == summary)

            return TraversalDecision::Continue;

        if (!child.is_slottable())

            return TraversalDecision::Continue;

        child.as_slottable().visit([&](auto& node) {

            descendants_assignment.append(JS::make_handle(node));

        });

Unexecuted instantiation: HTMLDetailsElement.cpp:auto Web::HTML::HTMLDetailsElement::update_shadow_tree_slots()::$_0::operator()<Web::DOM::Node>(Web::DOM::Node&) const::{lambda(auto:1&)#1}::operator()<JS::NonnullGCPtr<Web::DOM::Element> >(Web::DOM::Node&) const

Unexecuted instantiation: HTMLDetailsElement.cpp:auto Web::HTML::HTMLDetailsElement::update_shadow_tree_slots()::$_0::operator()<Web::DOM::Node>(Web::DOM::Node&) const::{lambda(auto:1&)#1}::operator()<JS::NonnullGCPtr<Web::DOM::Text> >(Web::DOM::Node&) const

        return TraversalDecision::Continue;

    });

    m_summary_slot->assign(move(summary_assignment));

    m_descendants_slot->assign(move(descendants_assignment));

    update_shadow_tree_style();

}

// https://html.spec.whatwg.org/#the-details-and-summary-elements:the-details-element-6

void HTMLDetailsElement::update_shadow_tree_style()

{

    if (!shadow_root())

        return;

    if (has_attribute(HTML::AttributeNames::open)) {

        MUST(m_descendants_slot->set_attribute(HTML::AttributeNames::style, R"~~~(

            display: block;

        )~~~"_string));

    } else {

        MUST(m_descendants_slot->set_attribute(HTML::AttributeNames::style, R"~~~(

            display: block;

            content-visibility: hidden;

        )~~~"_string));

    }

}

}