/*
 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/ext/MatrixConcatFunction.java,v 1.6 2006/02/05 21:47:42 elharo Exp $
 * $Revision: 1.6 $
 * $Date: 2006/02/05 21:47:42 $
 *
 * ====================================================================
 *
 * Copyright 2000-2002 bob mcwhirter & James Strachan.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   * 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.
 *
 *   * Neither the name of the Jaxen Project nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS 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 COPYRIGHT OWNER
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 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 Jaxen Project and was originally
 * created by bob mcwhirter <bob@werken.com> and
 * James Strachan <jstrachan@apache.org>.  For more information on the
 * Jaxen Project, please see <http://www.jaxen.org/>.
 *
 * $Id: MatrixConcatFunction.java,v 1.6 2006/02/05 21:47:42 elharo Exp $
 */

package org.orbeon.jaxen.function.ext;

import org.orbeon.jaxen.Context;
import org.orbeon.jaxen.Function;
import org.orbeon.jaxen.Navigator;
import org.orbeon.jaxen.function.StringFunction;

import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;

/** <p><b>Extension Function</b> <code><i>boolean</i> matrix-concat(<i>nodeSet</i>,<i>nodeSet</i>,<i>nodeSet*</i>)</code>
  *
  * @author James Pereira (JPereira@CT.BBD.CO.ZA)
  */

public class MatrixConcatFunction implements Function {

    public Object call(Context context, List args) {
        if ( args.size() >= 2 ) {
            return evaluate(args, context.getNavigator());
        }
        return null;
    }

    public static Object evaluate(List list, Navigator nav) {
        ArrayList matrix = new ArrayList();

        Iterator argIter = list.iterator();

        while (argIter.hasNext()) {
            ArrayList v = new ArrayList();
            Object obj = argIter.next();
            if (obj instanceof List) {
                List args = (List) obj;
                for ( int i = 0, size = args.size(); i < size; i++ ) {
                    v.add( StringFunction.evaluate( args.get(i), nav ) );
                }
            }
            else {
                v.add( StringFunction.evaluate( obj, nav ) );
            }
            matrix.add(v);
        }

        ArrayList result = new ArrayList();
        Enumeration elemList = new MatrixEnum( matrix );
        while (elemList.hasMoreElements()) {
            Object obj = elemList.nextElement();
            if (obj instanceof List) {
                StringBuffer text = new StringBuffer(127);
                List args = (List) obj;
                for (Iterator it = args.iterator(); it.hasNext(); ) {
                    text.append(it.next());
                }
                result.add( text.toString() );
            }
            else {
                result.add( obj );
            }
        }
        return result;
    }

    public static class MatrixEnum implements Enumeration {
        private ArrayList m_source;
        private int m_maxSize = 0;
        private int m_currIdx = -1;

        public MatrixEnum (ArrayList _source) {
            m_source = _source;

            for ( Iterator iter = m_source.iterator(); iter.hasNext(); ) {
                ArrayList element = (ArrayList) iter.next();
                int size = element.size();
                if (size > m_maxSize) {
                    m_maxSize = size;
                }
            }
        }

        public MatrixEnum (ArrayList _source, int _maxSize) {
            m_source = _source;
            m_maxSize = _maxSize;
        }

        public boolean hasMoreElements() {
            if ((m_maxSize != 0) && (++m_currIdx < m_maxSize)) {
                return true;
            }
            else {
                return false;
            }
        }

        public Object nextElement() {
            ArrayList result = new ArrayList();
            for ( Iterator iter = m_source.iterator(); iter.hasNext(); ) {
                ArrayList element = (ArrayList) iter.next();
                int size = element.size();
                if ( m_currIdx < size ) {
                    result.add( element.get( m_currIdx ) );
                }
                else {
                    if ( size > 0 ) {
                        result.add( element.get( size - 1 ) );
                    }
                    else {
                        // XXXX: what to do now?
                        result.add( "" );
                    }
                }
            }
            return result;
        }
    }
}