/*

* Copyright (c) 2007 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:  Compares W3C DOM Elements and CSS Selectors

 *

*/

package com.nokia.tools.themeinstaller.cssparser;

import java.util.Collection;

import java.util.Iterator;

import org.w3c.css.sac.AttributeCondition;

import org.w3c.css.sac.CSSException;

import org.w3c.css.sac.CombinatorCondition;

import org.w3c.css.sac.Condition;

import org.w3c.css.sac.ConditionalSelector;

import org.w3c.css.sac.DescendantSelector;

import org.w3c.css.sac.ElementSelector;

import org.w3c.css.sac.Selector;

import org.w3c.dom.Element;

import org.w3c.dom.Node;

/**

 * The Class CSSMatchMaker compares W3C DOM Elements and CSS Selectors. Match

 * method returns true if CSS Selector has style rules for the given DOM Element

 */

public class CSSMatchMaker

    {

    /** The Constant STRING_CLASS. */

    private static final String STRING_CLASS = "class";

    /** The Constant STRING_ID. */

    private static final String STRING_ID = "id";

    /** The Constant STRING_SPACE. */

    private static final String STRING_SPACE = " ";

    /** The pseudo class resolver. */

    private PseudoClassResolver iPseudoClassResolver;

    /**

     * Instantiates a new CSS Match Maker.

     */

    public CSSMatchMaker()

        {

        iPseudoClassResolver = new PseudoClassResolver();

        }

    /**

     * Compares if CSS rule with it's selector has style instructions for given

     * DOM Element.

     *

     * @param aElement W3C DOM Element

     * @param aRule The style rule

     *

     * @return true, if CSS Selector matches DOM Element

     */

    public boolean match( CSSRule aRule, Element aElement ){

        aRule.resetSpecificity();

        return match( aRule.getSelector(), aRule.getSpecificity(), aElement );

    }

    /**

     * Compares if CSS rule's selector has style instructions for given DOM

     * Element.

     *

     * @param aSelector the a selector

     * @param aSpecificity CSSRules specificity table to be updated during the

     *            comparison

     * @param aElement the a element

     *

     * @return true, if given selector match DOM Element

     */

    private boolean match( Selector aSelector, CSSSpecificity aSpecificity, Element aElement )

        {

        switch ( aSelector.getSelectorType() )

            {

            case Selector.SAC_ELEMENT_NODE_SELECTOR:

                {

                ElementSelector eSelector = ( ElementSelector ) aSelector;

                String name = eSelector.getLocalName();

//                if("box".equals(aElement.getLocalName())&& "box".equals(name) ){

//                	System.out.println("!!!");

//                }

                if ( name == null || name.equals( aElement.getLocalName() ) )

                    {

                    aSpecificity.incElement();

                    return true;

                    }

                return false;

                }

            case Selector.SAC_CONDITIONAL_SELECTOR:

                {

                ConditionalSelector cSelector = ( ConditionalSelector ) aSelector;

                if ( !match( cSelector.getSimpleSelector(), aSpecificity,

                        aElement ) )

                    {

                    return false;

                    }

                return matchCondition( cSelector.getCondition(), aSpecificity,

                        aElement );

                }

            case Selector.SAC_CHILD_SELECTOR:

                {

                DescendantSelector dSelector = ( DescendantSelector ) aSelector;

                if ( !match( dSelector.getSimpleSelector(), aSpecificity,

                        aElement ) )

                    {

                    return false;

                    }

                return match( dSelector.getAncestorSelector(), aSpecificity,

                        ( Element ) aElement.getParentNode() );

                }

            case Selector.SAC_DESCENDANT_SELECTOR:

                {

                DescendantSelector dSelector = ( DescendantSelector ) aSelector;

                if ( !match( dSelector.getSimpleSelector(), aSpecificity,

                        aElement ) )

                    {

                    return false;

                    }

                Node ancestor = aElement;

                while ( ( ancestor = ancestor.getParentNode() ) != null )

                    {

                    if ( ancestor.getNodeType() == Node.ELEMENT_NODE )

                        {

                        if ( match( dSelector.getAncestorSelector(),

                                aSpecificity, ( Element ) ancestor ) )

                            {

                            return true;

                            }

                        }

                    }

                return false;

                }

            case Selector.SAC_ANY_NODE_SELECTOR:

            case Selector.SAC_DIRECT_ADJACENT_SELECTOR:

            case Selector.SAC_CDATA_SECTION_NODE_SELECTOR:

            case Selector.SAC_COMMENT_NODE_SELECTOR:

            case Selector.SAC_NEGATIVE_SELECTOR:

            case Selector.SAC_PROCESSING_INSTRUCTION_NODE_SELECTOR:

            case Selector.SAC_PSEUDO_ELEMENT_SELECTOR:

            case Selector.SAC_ROOT_NODE_SELECTOR:

            case Selector.SAC_TEXT_NODE_SELECTOR:

                {

                throw new CSSException( "Selector : "

                        + aSelector.getSelectorType() + " not supported" );

                }

            default:

                throw new CSSException( "Unknown selector : "

                        + aSelector.getSelectorType() );

            }

        }

    /**

     * For Conditional Selectors, it is also necessary to check if selectors

     * conditions match with the DOM Element.

     *

     * @param aCondition The condition of the conditional selector

     * @param aElement The DOM element

     * @param aSpecificity CSSRules specificity table to be updated during the

     *            comparison

     *

     * @return true, if given Condition match DOM Element

     */

    private boolean matchCondition( Condition aCondition,

            CSSSpecificity aSpecificity, Element aElement )

        {

        switch ( aCondition.getConditionType() )

            {

            case Condition.SAC_ID_CONDITION:

                {

                AttributeCondition idCondition = ( AttributeCondition ) aCondition;

                String idAttribute = aElement.getAttribute( STRING_ID );

                String[] idTexts = idAttribute.split( STRING_SPACE );

                for ( int i = 0; i < idTexts.length; i++ )

                    {

                    String idText = idTexts[ i ];

                    if ( idAttribute != null

                            && idText.equals( idCondition.getValue() ) )

                        {

                        aSpecificity.incID();

                        return true;

                        }

                    }

                return false;

                }

            case Condition.SAC_CLASS_CONDITION:

                {

                AttributeCondition classCondition = ( AttributeCondition ) aCondition;

                String classAttribute = aElement.getAttribute( STRING_CLASS );

                String[] classTexts = classAttribute.split( STRING_SPACE );

                for ( int i = 0; i < classTexts.length; i++ )

                    {

                    String classText = classTexts[ i ];

                    if ( classAttribute != null

                            && classText.equals( classCondition.getValue() ) )

                        {

                        aSpecificity.incAttribute();

                        return true;

                        }

                    }

                return false;

                }

            case Condition.SAC_AND_CONDITION:

                {

                CombinatorCondition combCondition = ( CombinatorCondition ) aCondition;

                return matchCondition( combCondition.getFirstCondition(),

                        aSpecificity, aElement )

                        && matchCondition( combCondition.getSecondCondition(),

                                aSpecificity, aElement );

                }

            case Condition.SAC_PSEUDO_CLASS_CONDITION:

                {

                Collection pseudoTypes = iPseudoClassResolver

                        .getPseudoTypes();

                for ( Iterator it = pseudoTypes.iterator(); it

                        .hasNext(); )

                    {

                    if ( it.next()

                            .equals( aCondition.toString().substring( 1 ) ) )

                        {

                        aSpecificity.incAttribute();

                        return true;

                        }

                    }

                return false;

                }

            case Condition.SAC_ATTRIBUTE_CONDITION:

            case Condition.SAC_ONE_OF_ATTRIBUTE_CONDITION:

            case Condition.SAC_BEGIN_HYPHEN_ATTRIBUTE_CONDITION:

            case Condition.SAC_OR_CONDITION:

            case Condition.SAC_NEGATIVE_CONDITION:

            case Condition.SAC_POSITIONAL_CONDITION:

            case Condition.SAC_LANG_CONDITION:

            case Condition.SAC_ONLY_CHILD_CONDITION:

            case Condition.SAC_ONLY_TYPE_CONDITION:

            case Condition.SAC_CONTENT_CONDITION:

                {

                throw new CSSException( "condition : "

                        + aCondition.getConditionType() + " not supported" );

                }

            default:

                throw new CSSException( "Unknown condition : "

                        + aCondition.getConditionType() );

            }

        }

    }