/*
 * $Id: LabelEndFunction.java,v 1.4 2003/03/05 21:59:47 jeremias Exp $
 * ============================================================================
 *                    The Apache Software License, Version 1.1
 * ============================================================================
 *
 * Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, 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.
 *
 * 3. The end-user documentation included with the redistribution, if any, must
 *    include the following acknowledgment: "This product includes software
 *    developed by the Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself, if
 *    and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "FOP" and "Apache Software Foundation" must not be used to
 *    endorse or promote products derived from this software without prior
 *    written permission. For written permission, please contact
 *    apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache", nor may
 *    "Apache" appear in their name, without prior written permission of the
 *    Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 THE
 * APACHE SOFTWARE FOUNDATION OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLU-
 * DING, 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.
 * ============================================================================
 *
 * This software consists of voluntary contributions made by many individuals
 * on behalf of the Apache Software Foundation and was originally created by
 * James Tauber <jtauber@jtauber.com>. For more information on the Apache
 * Software Foundation, please see <http://www.apache.org/>.
 */
package org.apache.fop.fo.expr;

import org.apache.fop.datatypes.Length;
import org.apache.fop.datatypes.LengthBase;
import org.apache.fop.datatypes.LinearCombinationLength;
import org.apache.fop.datatypes.PercentLength;
import org.apache.fop.fo.Property;
import org.apache.fop.fo.LengthProperty;
import org.apache.fop.fo.FONode;
import org.apache.fop.fo.flow.ListItem;

/**
 * Class modelling the label-end Property Value function. See Sec. 5.10.4 of the
 * XSL-FO spec.
 */
public class LabelEndFunction extends FunctionBase {

    /**
     * @return 0 (the number of arguments required for the label-end function)
     */
    public int nbArgs() {
        return 0;
    }

    /**
     *
     * @param args array of arguments for the function (none are needed, but
     * required for the Function interface)
     * @param pInfo PropertyInfo object for the function
     * @return the calculated label-end value for the list
     * @throws PropertyException if called from outside of an fo:list-item
     */
    public Property eval(Property[] args,
                         PropertyInfo pInfo) throws PropertyException {

        Length distance =
            pInfo.getPropertyList().get("provisional-distance-between-starts").getLength();
        Length separation =
            pInfo.getPropertyList().getNearestSpecified("provisional-label-separation").getLength();

        FONode item = pInfo.getFO();
        while (item != null && !(item instanceof ListItem)) {
            item = item.getParent();
        }
        if (item == null) {
            throw new PropertyException("label-end() called from outside an fo:list-item");
        }
        Length startIndent = ((ListItem)item).properties.get("start-indent").getLength();

        LinearCombinationLength labelEnd = new LinearCombinationLength();

        // Should be CONTAINING_REFAREA but that doesn't work
        LengthBase base = new LengthBase((ListItem)item, pInfo.getPropertyList(),
                                         LengthBase.CONTAINING_BOX);
        PercentLength refWidth = new PercentLength(1.0, base);

        labelEnd.addTerm(1.0, refWidth);
        labelEnd.addTerm(-1.0, distance);
        labelEnd.addTerm(-1.0, startIndent);
        labelEnd.addTerm(1.0, separation);

        return new LengthProperty(labelEnd);
    }

}