/**
 * Copyright (C) 2010 Orbeon, Inc.
 *
 * 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
 * 2.1 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.
 *
 * The full text of the license is available at http://www.gnu.org/copyleft/lesser.html
 */
package org.orbeon.oxf.portlet;

import java.io.IOException;
import java.io.Writer;

import javax.portlet.MimeResponse;

import org.apache.commons.lang.StringEscapeUtils;
import org.apache.commons.lang.StringUtils;
import org.orbeon.oxf.common.OXFException;

public class CopyOfWSRP2Utils
{
	private static final String BASE_TAG = "wsrp_rewrite";
	private static final char START_TAG_MARKER = '?';
	private static final String END_TAG = '/' + BASE_TAG;
	private static final char NAMESPACE_PLACEHOLDER_MARKER = '_';

	private MimeResponse mimeResponse;
	private Writer out;
	private String content;
	private String namespace;
	private boolean encodeForXML;
	private int currentPosition;

	public CopyOfWSRP2Utils(MimeResponse mimeResponse, String content, String namespace, boolean encodeForXML)
			throws IOException
	{
		this.mimeResponse = mimeResponse;
		this.content = content;
		this.namespace = namespace;
		this.encodeForXML = encodeForXML;
		currentPosition = 0;

		out = mimeResponse.getWriter();
	}

	private void parse() throws IOException
	{
		int nextTagPosition;
		while ((nextTagPosition = content.indexOf(BASE_TAG, currentPosition)) != -1)
		{
			passthruUntil(nextTagPosition);
			currentPosition = nextTagPosition + BASE_TAG.length();
			parseTag();
		}
		writeRemainder();
	}

	private void passthruUntil(int nextTagPosition) throws IOException
	{
		out.write(content, currentPosition, nextTagPosition - currentPosition);
	}

	private void writeRemainder() throws IOException
	{
		passthruUntil(content.length());
	}

	private void parseTag() throws IOException
	{
		if (isEscapeTag())
		{
			out.write(BASE_TAG);
			currentPosition += BASE_TAG.length();
		}
		else if (isStartTag())
		{
			int endTagPosition = content.indexOf(END_TAG);
			if (endTagPosition == -1)
				throw new OXFException("wsrp-rewrite tag at position " + (currentPosition - BASE_TAG.length())
						+ "is missing a closing tag");
			String tagValue = content.substring(currentPosition + 1, endTagPosition);
			currentPosition = endTagPosition + END_TAG.length();

			String decodedPortletURL = new WsrpToPortletURL(mimeResponse, tagValue).decode();
            if (encodeForXML)
            	decodedPortletURL = StringEscapeUtils.escapeXml(decodedPortletURL);
            out.write(decodedPortletURL);
		}
		else if (isNamespacePlaceholder())
		{
			out.write(namespace);
			++currentPosition;
		}
		else
			throw new OXFException("Invalid wsrp rewrite tagging at position " + currentPosition + " near '"
					+ StringUtils.substring(content, currentPosition - BASE_TAG.length(), currentPosition + 10) + "'");
	}

	private boolean isNamespacePlaceholder()
	{
		return content.charAt(currentPosition) == NAMESPACE_PLACEHOLDER_MARKER;
	}

	private boolean isStartTag()
	{
		return content.charAt(currentPosition) == START_TAG_MARKER;
	}

	private boolean isEscapeTag()
	{
		return StringUtils.substring(content, currentPosition, currentPosition + BASE_TAG.length()).equals(BASE_TAG);
	}

	/**
	 * This method parses a string containing WSRP Consumer URL and namespace
	 * encoding and encode the URLs and namespaces as per the Portlet API.
	 * 
	 * It is possible to escape by using the string wsrp_rewritewsrp_rewrite.
	 */
	public static void write(MimeResponse response, String content, String namespace, boolean encodeForXML)
			throws IOException
	{
		new CopyOfWSRP2Utils(response, content, namespace, encodeForXML).parse();
	}
}