/*
 * Copyright (C) 2019 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "WindowEventLoop.h"

#include "Document.h"

namespace WebCore {

static HashMap<RegistrableDomain, WindowEventLoop*>& windowEventLoopMap()
{
    RELEASE_ASSERT(isMainThread());
    static NeverDestroyed<HashMap<RegistrableDomain, WindowEventLoop*>> map;
    return map.get();
}

Ref<WindowEventLoop> WindowEventLoop::ensureForRegistrableDomain(const RegistrableDomain& domain)
{
    auto addResult = windowEventLoopMap().add(domain, nullptr);
    if (UNLIKELY(addResult.isNewEntry)) {
        auto newEventLoop = adoptRef(*new WindowEventLoop(domain));
        addResult.iterator->value = newEventLoop.ptr();
        return newEventLoop;
    }
    return *addResult.iterator->value;
}

inline WindowEventLoop::WindowEventLoop(const RegistrableDomain& domain)
    : m_domain(domain)
{
}

WindowEventLoop::~WindowEventLoop()
{
    auto didRemove = windowEventLoopMap().remove(m_domain);
    RELEASE_ASSERT(didRemove);
}

void WindowEventLoop::queueTask(TaskSource source, ScriptExecutionContext& context, TaskFunction&& task)
{
    ASSERT(isMainThread());
    ASSERT(is<Document>(context));
    scheduleToRunIfNeeded();
    m_tasks.append(Task { source, WTFMove(task), downcast<Document>(context).identifier() });
}

void WindowEventLoop::suspend(Document&)
{
    ASSERT(isMainThread());
}

void WindowEventLoop::resume(Document& document)
{
    ASSERT(isMainThread());
    if (!m_documentIdentifiersForSuspendedTasks.contains(document.identifier()))
        return;
    scheduleToRunIfNeeded();
}

void WindowEventLoop::stop(Document& document)
{
    m_tasks.removeAllMatching([identifier = document.identifier()] (auto& task) {
        return task.documentIdentifier == identifier;
    });
}

void WindowEventLoop::scheduleToRunIfNeeded()
{
    if (m_isScheduledToRun)
        return;

    m_isScheduledToRun = true;
    callOnMainThread([eventLoop = makeRef(*this)] () {
        eventLoop->m_isScheduledToRun = false;
        eventLoop->run();
    });
}

void WindowEventLoop::run()
{
    if (m_tasks.isEmpty())
        return;

    Vector<Task> tasks = WTFMove(m_tasks);
    m_documentIdentifiersForSuspendedTasks.clear();
    Vector<Task> remainingTasks;
    for (auto& task : tasks) {
        auto* document = Document::allDocumentsMap().get(task.documentIdentifier);
        if (!document || document->activeDOMObjectsAreStopped())
            continue;
        if (document->activeDOMObjectsAreSuspended()) {
            m_documentIdentifiersForSuspendedTasks.add(task.documentIdentifier);
            remainingTasks.append(WTFMove(task));
            continue;
        }
        task.task();
    }
    for (auto& task : m_tasks)
        remainingTasks.append(WTFMove(task));
    m_tasks = WTFMove(remainingTasks);
}

} // namespace WebCore