/*
 * eXist Open Source Native XML Database
 * Copyright (C) 2001-2007 The eXist Project
 * http://exist-db.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *  
 * This program 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 Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *  
 *  $Id$
 */
package org.exist.xquery;

import org.exist.memtree.MemTreeBuilder;
import org.exist.memtree.NodeImpl;
import org.exist.xquery.util.ExpressionDumper;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Constructor for processing-instruction nodes.
 * 
 * @author wolf
 */
public class PIConstructor extends NodeConstructor {

	private static Pattern wsContentStart = Pattern.compile("^(\\s)*(.*)");
	private final String target;
	private String data = null;
	
	public PIConstructor(XQueryContext context, String pi) throws XPathException {
		super(context);
        //TODO : handle this from the parser -pb
		int p = pi.indexOf(" ");
		if(p == Constants.STRING_NOT_FOUND) {
            target = pi;
        } else {
            target = pi.substring(0, p);
            if(++p < pi.length()) {
                data = pi.substring(p);

                Matcher m = wsContentStart.matcher(data);
                if (m.matches()) {
                    data = m.group(2);
                }
            }
        }
        if (target.equalsIgnoreCase("xml")) {
            throw new XPathException(this,   "XPST0003 : The target 'xml' is not allowed in XML processing instructions.");
        }
	}
    
	/* (non-Javadoc)
	 * @see org.exist.xquery.Expression#eval(org.exist.xquery.StaticContext, org.exist.dom.DocumentSet, org.exist.xquery.value.Sequence, org.exist.xquery.value.Item)
	 */
	public Sequence eval(
		Sequence contextSequence,
		Item contextItem)
		throws XPathException {
        if (newDocumentContext)
            context.pushDocumentContext();
        try {
            MemTreeBuilder builder = context.getDocumentBuilder();
            int nodeNr = builder.processingInstruction(target, data);
            NodeImpl node = builder.getDocument().getNode(nodeNr);
            return node;
        } finally {
            if (newDocumentContext)
                context.popDocumentContext();
        }
    }

	 /* (non-Javadoc)
     * @see org.exist.xquery.Expression#dump(org.exist.xquery.util.ExpressionDumper)
     */
    public void dump(ExpressionDumper dumper) {
        dumper.display("processing-instruction {");
        dumper.display(target);
        dumper.display("} {");
        dumper.startIndent();
        dumper.display(data);
        dumper.endIndent().nl().display("}");
    }
    
    public String toString() {
    	StringBuilder result = new StringBuilder();
    	result.append("processing-instruction {");
    	result.append(target.toString());
    	result.append("} {");        
    	result.append(data.toString());
    	result.append("}");
    	return result.toString();
    }    
}