/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
 * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
 * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
 * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
 * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
 * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
 * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
 * Copyright (C) Research In Motion Limited 2011. All rights reserved.
 * Copyright (C) 2012 Google Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"
#include "VisitedLinkState.h"

#include "Frame.h"
#include "HTMLAnchorElement.h"
#include "HTMLNames.h"
#include "ElementTraversal.h"
#include "Page.h"
#include "PageGroup.h"

#if USE(PLATFORM_STRATEGIES)
#include "PlatformStrategies.h"
#include "VisitedLinkStrategy.h"
#endif

namespace WebCore {

using namespace HTMLNames;

inline static const AtomicString* linkAttribute(Element* element)
{
    if (!element->isLink())
        return 0;
    if (element->isHTMLElement())
        return &element->attributeWithoutSynchronization(HTMLNames::hrefAttr);
    if (element->isSVGElement())
        return &element->getAttribute(XLinkNames::hrefAttr);
    return 0;
}

PassOwnPtr<VisitedLinkState> VisitedLinkState::create(Document* document)
{
    return adoptPtr(new VisitedLinkState(document));
}

VisitedLinkState::VisitedLinkState(Document* document)
    :m_document(document)
{
}

void VisitedLinkState::invalidateStyleForAllLinks()
{
    if (m_linksCheckedForVisitedState.isEmpty())
        return;
    for (Element* element = ElementTraversal::firstWithin(m_document); element; element = ElementTraversal::next(element)) {
        if (element->isLink())
            element->setNeedsStyleRecalc();
    }
}

inline static LinkHash linkHashForElement(Document* document, Element* element)
{
    if (element->hasTagName(aTag))
        return static_cast<HTMLAnchorElement*>(element)->visitedLinkHash();
    if (const AtomicString* attribute = linkAttribute(element))
        return WebCore::visitedLinkHash(document->baseURL(), *attribute);
    return 0;
}

void VisitedLinkState::invalidateStyleForLink(LinkHash linkHash)
{
    if (!m_linksCheckedForVisitedState.contains(linkHash))
        return;
    for (Element* element = ElementTraversal::firstWithin(m_document); element; element = ElementTraversal::next(element)) {
        if (linkHashForElement(m_document, element) == linkHash)
            element->setNeedsStyleRecalc();
    }
}

EInsideLink VisitedLinkState::determineLinkStateSlowCase(Element* element)
{
    ASSERT(element->isLink());

    const AtomicString* attribute = linkAttribute(element);
    if (!attribute || attribute->isNull())
        return NotInsideLink;

    // An empty href refers to the document itself which is always visited. It is useful to check this explicitly so
    // that visited links can be tested in platform independent manner, without explicit support in the test harness.
    if (attribute->isEmpty())
        return InsideVisitedLink;

    LinkHash hash;
    if (element->hasTagName(aTag))
        hash = static_cast<HTMLAnchorElement*>(element)->visitedLinkHash();
    else
        hash = WebCore::visitedLinkHash(element->document()->baseURL(), *attribute);

    if (!hash)
        return InsideUnvisitedLink;

    Frame* frame = element->document()->frame();
    if (!frame)
        return InsideUnvisitedLink;

    Page* page = frame->page();
    if (!page)
        return InsideUnvisitedLink;

    m_linksCheckedForVisitedState.add(hash);

#if USE(PLATFORM_STRATEGIES)
    return platformStrategies()->visitedLinkStrategy()->isLinkVisited(page, hash, element->document()->baseURL(), *attribute) ? InsideVisitedLink : InsideUnvisitedLink;
#else
    return page->group().isLinkVisited(hash) ? InsideVisitedLink : InsideUnvisitedLink;
#endif
}


}
