/*
 JSPWiki - a JSP-based WikiWiki clone.

 Copyright (C) 2001-2003 Janne Jalkanen (Janne.Jalkanen@iki.fi)

 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.

 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package com.ecyrd.jspwiki.tags;

import java.io.IOException;
import java.io.Serializable;
import java.util.LinkedList;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import javax.servlet.jsp.JspWriter;

import org.apache.log4j.Logger;

import com.ecyrd.jspwiki.WikiContext;

/**
 * Implement a "breadcrumb" (most recently visited) trail. This tag can be added
 * to any view jsp page. Separate breadcrumb trails are not tracked across
 * multiple browser windows.<br>
 * The optional attributes are:
 * <p>
 * <b>maxpages</b>, the number of pages to store, 10 by default<br>
 * <b>separator</b>, the separator string to use between pages, " | " by
 * default<br>
 * </p>
 * 
 * <p>
 * This class is implemented by storing a breadcrumb trail, which is a fixed
 * size queue, into a session variable "breadCrumbTrail". This queue is
 * displayed as a series of links separated by a separator character.
 * </p>
 * 
 * <p>
 * JPSR: cambiado el comportamiento para que cuando el usuario haga click en un enlace del
 * breadcrumb se haga un pop del resto de enlaces hasta el final del breadcrumb, quedando
 * un comportamiento más intuitivo. Esto se consigue gestionando un parámetro adicional en la
 * request, navbreadcrumb. La página Wiki.jsp también ha sido cambiada un poco para evitar que
 * se muestre este parámetro en la url (hace un redirect a si misma pero pasando solamente el
 * parámetro page a la request). De este modo se consigue que el comportamiento añadido sea 
 * totalmente transparente al resto de la aplicación. 
 * </p>
 * <p>
 * JPSR: changed behaviour so when a user clicks on a breadcrumb link, the next links until 
 * end of breadcrumb are "popped" out, which is a little more intuitive. This is done
 * managing the navbreadcrumb request parameter. Wiki.jsp has also a little change to
 * avoid showing this parameter on the url (it performs a redirect to itself with only
 * the page parameter). By doing this we achieve that the added behaviour remains transparent
 * to the rest of the application.
 * </p>
 * 
 * @author Ken Liu ken@kenliu.net / modified by Juan Pablo Santos Rodríguez (juanpablo.santos at vass dot es)
 */
public class BreadcrumbsTag extends WikiTagBase {
	private static final long serialVersionUID = 0L;

	private static final Logger log = Logger.getLogger(BreadcrumbsTag.class);

	private static final String BREADCRUMBTRAIL_KEY = "breadCrumbTrail";

	private int m_maxQueueSize = 11;

	private String m_separator = " > ";

	public int getMaxpages() {
		return m_maxQueueSize;
	}

	public void setMaxpages(int maxpages) {
		m_maxQueueSize = maxpages + 1;
	}

	public String getSeparator() {
		return m_separator;
	}

	public void setSeparator(String separator) {
		m_separator = separator;
	}

	public final int doWikiStartTag() throws IOException {
		HttpSession session = pageContext.getSession();
		HttpServletRequest request = m_wikiContext.getHttpRequest(); // para gestionar la request más fácilmente
																	 // used to handle the request more easily
		FixedQueue trail = (FixedQueue) session
				.getAttribute(BREADCRUMBTRAIL_KEY);

		String page = m_wikiContext.getPage().getName();

		if (trail == null) {
			trail = new FixedQueue(m_maxQueueSize);
		}
		
		// Detectar si el usuario ha hecho click en el breadcrumb
		// Detect if user has clicked on breadcrumb
        String clickOnBreadcrumb = request.getParameter("navbreadcrumb");
        if (clickOnBreadcrumb != null) {
            int newSize = Integer.parseInt(clickOnBreadcrumb);
            if (newSize >= 0) {
                while (trail.size() >= newSize) {
                    trail.pop();
				}
			}
		}

		if (m_wikiContext.getRequestContext().equals(WikiContext.VIEW)) {
			if (trail.isEmpty()) {
				trail.push(page);
			} else {
				//
				// Don't add the page to the queue if the page was just
				// refreshed
				//
				if (!((String) trail.getLast()).equals(page)) {
					trail.push(page);
					log.debug("added page: " + page);
				}
				log.debug("didn't add page because of refresh");
			}
		}

		session.setAttribute(BREADCRUMBTRAIL_KEY, trail);

		//
		// Print out the breadcrumb trail
		//

		// FIXME: this code would be much simpler if we could just output the
		// [pagename] and then use the
		// wiki engine to output the appropriate wikilink

		JspWriter out = pageContext.getOut();
		int queueSize = trail.size();
		String linkclass = "wikipage";
		String curPage = null;
		
		for (int i = 0; i < queueSize - 1; i++) {
			curPage = (String) trail.get(i);

			// FIXME: I can't figure out how to detect the appropriate jsp page
			// to put here, so I hard coded Wiki.jsp
			// This breaks when you view an attachment metadata page
			String href = m_wikiContext.getViewURL(curPage);
			String hrefComplete = request.getScheme() + "://" + request.getServerName() + ":" +
					request.getServerPort() + href;
			
			out.print("<a class=\"" + linkclass + "\" " + "onmouseover=\"window.status='" + hrefComplete + 
					"';return true;\" href=\"" + href + "&amp;navbreadcrumb=" + i + 
					"\" >" + curPage + "</a>");
			// FIXMozilla: en los enlaces, si en el evento onmouseover se cambia el window.status y se devuelve
			// true entonces no lo cambia, que es lo que debería ocurrir cuando se devolviese false. Cfr con
			// http://www.quirksmode.org/bugreports/archives/mozilla/index.html
			// FIXMozilla: on anchors, if onmouseover event changes window.status and returns true then it does 
			// *not* do anything, just the behaviour it should have when returning false. Check with
			// http://www.quirksmode.org/bugreports/archives/mozilla/index.html 

			if (i < queueSize - 2) {
				out.print(m_separator);
			}
		}

		return SKIP_BODY;
	}

	/**
	 * Extends the LinkedList class to provide a fixed-size queue implementation
	 */
	private static class FixedQueue extends LinkedList implements Serializable {
		private int m_size;

		private static final long serialVersionUID = 0L;

		FixedQueue(int size) {
			m_size = size;
		}

		Object push(Object o) {
			add(o);
			if (size() > m_size) {
				return removeFirst();
			}

			return null;
		}
		
		Object pop() {
			if (size() > 0) { 
				return removeLast();
			}
			return null;
		}
	}

}