/*

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */
package org.apache.batik.dom.svg;

import org.apache.batik.parser.LengthListHandler;
import org.apache.batik.parser.LengthListParser;
import org.apache.batik.parser.ParseException;
import org.w3c.dom.DOMException;
import org.w3c.dom.Element;
import org.w3c.dom.svg.SVGException;
import org.w3c.dom.svg.SVGLength;
import org.w3c.dom.svg.SVGLengthList;

/**
 * This class is the implementation of
 * <code>SVGLengthList</code>.
 *
 * @author <a href="mailto:nicolas.socheleau@bitflash.com">Nicolas Socheleau</a>
 * @version $Id: AbstractSVGLengthList.java 489226 2006-12-21 00:05:36Z cam $
 */
public abstract class AbstractSVGLengthList
    extends AbstractSVGList
    implements SVGLengthList {

    /**
     * This length list's direction.
     */
    protected short direction;

    /**
     * Separator for a length list.
     */
    public static final String SVG_LENGTH_LIST_SEPARATOR
        = " ";

    /**
     * Return the separator between values in the list.
     */
    protected String getItemSeparator() {
        return SVG_LENGTH_LIST_SEPARATOR;
    }

    /**
     * Create an SVGException when the checkItemType fails.
     * @return SVGException
     */
    protected abstract SVGException createSVGException(short type,
                                                       String key,
                                                       Object[] args);

    /**
     * Returns the element owning this SVGLengthList.
     */
    protected abstract Element getElement();

    /**
     * Creates a new SVGLengthList.
     */
    protected AbstractSVGLengthList(short direction) {
        this.direction = direction;
    }

    /**
     * <b>DOM</b>: Implements {@link SVGLengthList#initialize(SVGLength)}.
     */
    public SVGLength initialize(SVGLength newItem)
            throws DOMException, SVGException {
        return (SVGLength) initializeImpl(newItem);
    }

    /**
     * <b>DOM</b>: Implements {@link SVGLengthList#getItem(int)}.
     */
    public SVGLength getItem(int index) throws DOMException {
        return (SVGLength) getItemImpl(index);
    }

    /**
     * <b>DOM</b>: Implements {@link
     * SVGLengthList#insertItemBefore(SVGLength,int)}.
     */
    public SVGLength insertItemBefore(SVGLength newItem, int index)
            throws DOMException, SVGException {
        return (SVGLength) insertItemBeforeImpl(newItem, index);
    }

    /**
     * <b>DOM</b>: Implements {@link
     * SVGLengthList#replaceItem(SVGLength,int)}.
     */
    public SVGLength replaceItem(SVGLength newItem, int index)
            throws DOMException, SVGException {
        return (SVGLength) replaceItemImpl(newItem,index);
    }

    /**
     * <b>DOM</b>: Implements {@link SVGLengthList#removeItem(int)}.
     */
    public SVGLength removeItem(int index) throws DOMException {
        return (SVGLength) removeItemImpl(index);
    }

    /**
     * <b>DOM</b>: Implements {@link SVGLengthList#appendItem(SVGLength)}.
     */
    public SVGLength appendItem(SVGLength newItem)
            throws DOMException, SVGException {
        return (SVGLength) appendItemImpl(newItem);
    }

    /**
     * Creates a new {@link SVGItem} object from the given {@link SVGLength}.
     */
    protected SVGItem createSVGItem(Object newItem) {
        SVGLength l = (SVGLength) newItem;
        return new SVGLengthItem(l.getUnitType(), l.getValueInSpecifiedUnits(),
                                 direction);
    }

    /**
     * Parses the attribute associated with this SVGLengthList.
     *
     * @param value attribute value
     * @param handler length list handler
     */
    protected void doParse(String value, ListHandler handler)
        throws ParseException{

        LengthListParser lengthListParser = new LengthListParser();

        LengthListBuilder builder = new LengthListBuilder(handler);

        lengthListParser.setLengthListHandler(builder);
        lengthListParser.parse(value);
    }

    /**
     * Asserts that the given item is an {@link SVGLengthList}.
     */
    protected void checkItemType(Object newItem) throws SVGException {
        if (!(newItem instanceof SVGLength)) {
            createSVGException(SVGException.SVG_WRONG_TYPE_ERR,
                               "expected.length", null);
        }
    }

    /**
     * An {@link SVGLength} in the list.
     */
    protected class SVGLengthItem extends AbstractSVGLength implements SVGItem {

        /**
         * Creates a new SVGLengthItem.
         */
        public SVGLengthItem(short type, float value, short direction) {
            super(direction);
            this.unitType = type;
            this.value = value;
        }

        /**
         * Returns the element this length is associated with.
         */
        protected SVGOMElement getAssociatedElement() {
            return (SVGOMElement) AbstractSVGLengthList.this.getElement();
        }

        /**
         * List the item belongs to.
         */
        protected AbstractSVGList parentList;

        /**
         * Assigns a parent list to this item.
         * @param list The list the item belongs.
         */
        public void setParent(AbstractSVGList list) {
            parentList = list;
        }

        /**
         * Returns the parent list of this item.
         */
        public AbstractSVGList getParent() {
            return parentList;
        }

        /**
         * Notifies the parent list that this item has changed.
         */
        protected void reset() {
            if (parentList != null) {
                parentList.itemChanged();
            }
        }
    }

    /**
     * Helper class to interface the {@link LengthListParser} and the
     * {@link ListHandler}.
     */
    protected class LengthListBuilder implements LengthListHandler {

        /**
         * The ListHandler to pass newly created {@link SVGLengthItem} objects
         * to.
         */
        protected ListHandler listHandler;

        /**
         * The the length value just parsed.
         */
        protected float currentValue;

        /**
         * The length unit just parsed.
         */
        protected short currentType;

        /**
         * Creates a new LengthListBuilder.
         */
        public LengthListBuilder(ListHandler listHandler) {
            this.listHandler = listHandler;
        }

        /**
         * Implements {@link LengthListHandler#startLengthList()}.
         */
        public void startLengthList() throws ParseException {
            listHandler.startList();
        }

        /**
         * Implements {@link LengthListHandler#startLength()}.
         */
        public void startLength() throws ParseException {
            currentType = SVGLength.SVG_LENGTHTYPE_NUMBER;
            currentValue = 0.0f;
        }

        /**
         * Implements {@link LengthListHandler#lengthValue(float)}.
         */
        public void lengthValue(float v) throws ParseException {
            currentValue = v;
        }

        /**
         * Implements {@link LengthListHandler#em()}.
         */
        public void em() throws ParseException {
            currentType = SVGLength.SVG_LENGTHTYPE_EMS;
        }

        /**
         * Implements {@link LengthListHandler#ex()}.
         */
        public void ex() throws ParseException {
            currentType = SVGLength.SVG_LENGTHTYPE_EXS;
        }

        /**
         * Implements {@link LengthListHandler#in()}.
         */
        public void in() throws ParseException {
            currentType = SVGLength.SVG_LENGTHTYPE_IN;
        }

        /**
         * Implements {@link LengthListHandler#cm()}.
         */
        public void cm() throws ParseException {
            currentType = SVGLength.SVG_LENGTHTYPE_CM;
        }

        /**
         * Implements {@link LengthListHandler#mm()}.
         */
        public void mm() throws ParseException {
            currentType = SVGLength.SVG_LENGTHTYPE_MM;
        }

        /**
         * Implements {@link LengthListHandler#pc()}.
         */
        public void pc() throws ParseException {
            currentType = SVGLength.SVG_LENGTHTYPE_PC;
        }

        /**
         * Implements {@link LengthListHandler#pt()}.
         */
        public void pt() throws ParseException {
            currentType = SVGLength.SVG_LENGTHTYPE_EMS;
        }

        /**
         * Implements {@link LengthListHandler#px()}.
         */
        public void px() throws ParseException {
            currentType = SVGLength.SVG_LENGTHTYPE_PX;
        }

        /**
         * Implements {@link LengthListHandler#percentage()}.
         */
        public void percentage() throws ParseException {
            currentType = SVGLength.SVG_LENGTHTYPE_PERCENTAGE;
        }

        /**
         * Implements {@link LengthListHandler#endLength()}.
         */
        public void endLength() throws ParseException {
            listHandler.item
                (new SVGLengthItem(currentType,currentValue,direction));
        }

        /**
         * Implements {@link LengthListHandler#endLengthList()}.
         */
        public void endLengthList() throws ParseException {
            listHandler.endList();
        }
    }
}
