/*
 * 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.
 *
 * 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.
 */

#ifndef SelectorChecker_h
#define SelectorChecker_h

#include "Attribute.h"
#include "CSSSelector.h"
#include "InspectorInstrumentation.h"
#include "SpaceSplitString.h"
#include "StyledElement.h"
#include <wtf/HashSet.h>
#include <wtf/Vector.h>

namespace WebCore {

class CSSSelector;
class RenderScrollbar;
class RenderStyle;

class SelectorChecker {
    WTF_MAKE_NONCOPYABLE(SelectorChecker);
    enum class Match { SelectorMatches, SelectorFailsLocally, SelectorFailsAllSiblings, SelectorFailsCompletely };

	enum class MatchType { VirtualPseudoElementOnly, Element };

	struct MatchResult {
		Match match;
		MatchType matchType;

		static MatchResult matches(MatchType matchType)
		{
			return { Match::SelectorMatches, matchType };
		}

		static MatchResult updateWithMatchType(MatchResult result, MatchType matchType)
		{
			if (matchType == MatchType::VirtualPseudoElementOnly)
				result.matchType = MatchType::VirtualPseudoElementOnly;
			return result;
		}

		static MatchResult fails(Match match)
		{
			return { match, MatchType::Element };
		}
	};

public:
    enum class Mode : unsigned char {
		ResolvingStyle = 0, CollectingRules, CollectingRulesIgnoringVirtualPseudoElements, QueryingRules
	};

    explicit SelectorChecker(Document*);

    struct StyleRelation {
        enum Type {
            AffectedByActive,
            AffectedByDrag,
            AffectedByEmpty,
            AffectedByHover,
            AffectedByPreviousSibling,
            AffectsNextSibling,
            ChildrenAffectedByBackwardPositionalRules,
            ChildrenAffectedByFirstChildRules,
            ChildrenAffectedByPropertyBasedBackwardPositionalRules,
            ChildrenAffectedByLastChildRules,
            FirstChild,
            LastChild,
            NthChildIndex,
            Unique,
        };
        StyleRelation(Element& element, Type type, unsigned value)
        : element(element)
        , type(type)
        , value(value)
        {
        }
        Element& element;
        Type type;
        unsigned value;
    };
    typedef Vector<StyleRelation, 8> StyleRelations;

    struct CheckingContext {
        CheckingContext(SelectorChecker::Mode resolvingMode)
            : resolvingMode(resolvingMode)
            , pseudoId(NOPSEUDO)
            , scrollbar(0)
            , scrollbarPart(NoPart)
            , scope(0)
        { }

        const SelectorChecker::Mode resolvingMode;
        PseudoId pseudoId;
        RenderScrollbar* scrollbar;
        ScrollbarPart scrollbarPart;
        const ContainerNode* scope;

        // FIXME: It would be nicer to have a separate object for return values. This requires some more work in the selector compiler.
        StyleRelations styleRelations;
        PseudoIdSet pseudoIDSet;
    };

    bool match(const CSSSelector&, const Element&, CheckingContext&, unsigned& specificity) const;

    static bool tagMatches(const Element*, const QualifiedName&);
    static bool isCommonPseudoClassSelector(const CSSSelector*);
    static bool matchesFocusPseudoClass(const Element*);
    static bool attributeSelectorMatches(const Element&, const QualifiedName&, const AtomicString& attributeValue, const CSSSelector&);
    static bool checkExactAttribute(const Element*, const CSSSelector*, const QualifiedName& selectorAttributeName, const AtomicStringImpl* value);

    enum LinkMatchMask { MatchLink = 1, MatchVisited = 2, MatchAll = MatchLink | MatchVisited };
    static unsigned determineLinkMatchType(const CSSSelector*);

    struct LocalContext;

private:
    MatchResult matchRecursively(CheckingContext&, const LocalContext&, PseudoIdSet&, unsigned& specificity) const;
    bool checkOne(CheckingContext&, const LocalContext&, PseudoIdSet&, MatchType&, unsigned& specificity) const;
    bool matchSelectorList(CheckingContext&, const LocalContext&, const Element&, const CSSSelectorList&, unsigned& specificity) const;

    bool checkScrollbarPseudoClass(const CheckingContext&, const Element&, const CSSSelector*) const;

    bool m_strictParsing;
    bool m_documentIsHTML;
};

ALWAYS_INLINE bool SelectorChecker::isCommonPseudoClassSelector(const CSSSelector* selector)
{
    if (selector->m_match != CSSSelector::PseudoClass)
        return false;
    CSSSelector::PseudoClassType pseudoType = selector->pseudoClassType();
    return pseudoType == CSSSelector::PseudoClassLink
#if ENABLE(CSS_SELECTORS_LEVEL4)
        || pseudoType == CSSSelector::PseudoClassAnyLink
#endif
        || pseudoType == CSSSelector::PseudoClassAnyLinkDeprecated
        || pseudoType == CSSSelector::PseudoClassVisited
        || pseudoType == CSSSelector::PseudoClassFocus;
}

ALWAYS_INLINE bool SelectorChecker::tagMatches(const Element* element, const QualifiedName& tagQName)
{
    if (tagQName == anyQName())
        return true;
    const AtomicString& localName = tagQName.localName();
    if (localName != starAtom && localName != element->localName())
        return false;
    const AtomicString& namespaceURI = tagQName.namespaceURI();
    return namespaceURI == starAtom || namespaceURI == element->namespaceURI();
}

ALWAYS_INLINE bool SelectorChecker::checkExactAttribute(const Element* element, const CSSSelector* selector, const QualifiedName& selectorAttributeName, const AtomicStringImpl* value)
{
    if (!element->hasAttributesWithoutUpdate())
        return false;
    const AtomicString& localName = element->isHTMLElement() ? selector->attributeCanonicalLocalName() : selectorAttributeName.localName();
	unsigned size = element->attributeCount();
    for (unsigned i = 0; i < size; ++i) {
        const Attribute& attribute = element->attributeAt(i);
        if (attribute.matches(selectorAttributeName.prefix(), localName, selectorAttributeName.namespaceURI()) && (!value || attribute.value().impl() == value))
			return true;
    }
    return false;
}

}

#endif
