/*

 * Copyright (c) 2024, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>

 *

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

 */

#include <LibWeb/HTML/Navigable.h>

#include <LibWeb/HTML/SessionHistoryTraversalQueue.h>

namespace Web::HTML {

JS_DEFINE_ALLOCATOR(SessionHistoryTraversalQueue);

JS_DEFINE_ALLOCATOR(SessionHistoryTraversalQueueEntry);

JS::NonnullGCPtr<SessionHistoryTraversalQueueEntry> SessionHistoryTraversalQueueEntry::create(JS::VM& vm, JS::NonnullGCPtr<JS::HeapFunction<void()>> steps, JS::GCPtr<HTML::Navigable> target_navigable)

{

    return vm.heap().allocate_without_realm<SessionHistoryTraversalQueueEntry>(steps, target_navigable);

}

void SessionHistoryTraversalQueueEntry::visit_edges(JS::Cell::Visitor& visitor)

{

    Base::visit_edges(visitor);

    visitor.visit(m_steps);

    visitor.visit(m_target_navigable);

}

SessionHistoryTraversalQueue::SessionHistoryTraversalQueue()

{

    m_timer = Core::Timer::create_single_shot(0, [this] {

        if (m_is_task_running && m_queue.size() > 0) {

            m_timer->start();

            return;

        }

        while (m_queue.size() > 0) {

            m_is_task_running = true;

            auto entry = m_queue.take_first();

            entry->execute_steps();

            m_is_task_running = false;

        }

    });

}

void SessionHistoryTraversalQueue::visit_edges(JS::Cell::Visitor& visitor)

{

    Base::visit_edges(visitor);

    visitor.visit(m_queue);

}

void SessionHistoryTraversalQueue::append(JS::NonnullGCPtr<JS::HeapFunction<void()>> steps)

{

    m_queue.append(SessionHistoryTraversalQueueEntry::create(vm(), steps, nullptr));

    if (!m_timer->is_active()) {

        m_timer->start();

    }

}

void SessionHistoryTraversalQueue::append_sync(JS::NonnullGCPtr<JS::HeapFunction<void()>> steps, JS::GCPtr<Navigable> target_navigable)

{

    m_queue.append(SessionHistoryTraversalQueueEntry::create(vm(), steps, target_navigable));

    if (!m_timer->is_active()) {

        m_timer->start();

    }

}

// https://html.spec.whatwg.org/multipage/browsing-the-web.html#sync-navigations-jump-queue

JS::GCPtr<SessionHistoryTraversalQueueEntry> SessionHistoryTraversalQueue::first_synchronous_navigation_steps_with_target_navigable_not_contained_in(HashTable<JS::NonnullGCPtr<Navigable>> const& set)

{

    auto index = m_queue.find_first_index_if([&set](auto const& entry) -> bool {

        return (entry->target_navigable() != nullptr) && !set.contains(*entry->target_navigable());

    });

    if (index.has_value())

        return m_queue.take(*index);

    return {};

}

}