/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.help.internal.webapp.data;
import java.io.*;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;

import org.eclipse.help.*;
import org.eclipse.help.internal.HelpSystem;
import org.eclipse.help.internal.webapp.servlet.*;

/**
 * Helper class for tocView.jsp initialization
 */
public class TocData extends RequestData {

	// Request parameters
	private String tocHref;
	private String topicHref;

	// help form of selected topic href
	private String topicHelpHref;
	// Selected TOC
	private int selectedToc;

	// List of TOC's
	private IToc[] tocs;

	// images directory
	private String imagesDirectory;

	/**
	 * Constructs the xml data for the contents page.
	 * @param context
	 * @param request
	 */
	public TocData(ServletContext context, HttpServletRequest request) {
		super(context, request);

		this.tocHref = request.getParameter("toc");
		this.topicHref = request.getParameter("topic");
		if (tocHref != null && tocHref.length() == 0)
			tocHref = null;
		if (topicHref != null && topicHref.length() == 0)
			topicHref = null;

		imagesDirectory = preferences.getImagesDirectory();

		loadTocs();
	}

	// Accessor methods to avoid exposing help classes directly to JSP.
	// Note: this seems ok for now, but maybe we need to reconsider this 
	//       and allow help classes in JSP's.

	public int getTocCount() {
		return tocs.length;
	}

	public String getTocLabel(int i) {
		return tocs[i].getLabel();
	}

	public String getTocHref(int i) {
		return tocs[i].getHref();
	}

	public String getTocDescriptionTopic(int i) {
		return UrlUtil.getHelpURL(tocs[i].getTopic(null).getHref());
	}

	/**
	 * Returns the selected TOC
	 * @return int
	 */
	public int getSelectedToc() {
		return selectedToc;
	}

	/**
	 * Returns the topic to display.
	 * If there is a TOC, return its topic description.
	 * Return null if no topic is specified and there is no toc description.
	 * @return String
	 */
	public String getSelectedTopic() {
		if (topicHref != null && topicHref.length() > 0)
			return UrlUtil.getHelpURL(topicHref);
		else {
			if (selectedToc == -1)
				return null;
			IToc toc = tocs[selectedToc];
			ITopic tocDescription = toc.getTopic(null);
			if (tocDescription != null)
				return UrlUtil.getHelpURL(tocDescription.getHref());
			else
				return UrlUtil.getHelpURL(null);
		}
	}

	/**
	 * Returns a list of all the TOC's as xml elements.
	 * Individual TOC's are not loaded yet.
	 * @return Element[]
	 */
	public IToc[] getTocs() {
		return tocs;
	}

	private void loadTocs() {
		tocs = HelpSystem.getTocManager().getTocs(getLocale());
		// Find the requested TOC
		selectedToc = -1;
		if (tocHref != null && tocHref.length() > 0) {
			tocs = getTocs();
			for (int i = 0; selectedToc == -1 && i < tocs.length; i++)
				if (tocHref.equals(tocs[i].getHref()))
					selectedToc = i;
		} else {
			// try obtaining the TOC from the topic
			selectedToc = findTocContainingTopic(topicHref);
		}
	}

	/**
	 * Finds a TOC that contains specified topic
	 * @param topic the topic href
	 */
	private int findTocContainingTopic(String topic) {
		if (topic == null || topic.equals(""))
			return -1;

		int index = topic.indexOf("/topic/");
		if (index != -1)
			topic = topic.substring(index + 6);
		index = topic.indexOf('?');
		if (index != -1)
			topic = topic.substring(0, index);

		if (topic == null || topic.equals(""))
			return -1;

		tocs = getTocs();
		for (int i = 0; i < tocs.length; i++)
			if (tocs[i].getTopic(topic) != null)
				return i;

		// nothing found
		return -1;
	}

	/**
	 * Generates the HTML code (a tree) for a TOC.
	 * @param toc
	 * @param out
	 * @throws IOException
	 */
	public void generateToc(int toc, Writer out) throws IOException {

		ITopic[] topics = tocs[toc].getTopics();
		for (int i = 0; i < topics.length; i++) {
			generateTopic(topics[i], out);
		}
	}

	private void generateTopic(ITopic topic, Writer out) throws IOException {

		out.write("<li>");

		boolean hasNodes = topic.getSubtopics().length > 0;
		if (hasNodes) {
			out.write("<img src='");
			out.write(imagesDirectory);
			out.write("/plus.gif' class='collapsed' >");
			out.write("<a href='" + UrlUtil.getHelpURL(topic.getHref()) + "'>");
			out.write("<img src='");
			out.write(imagesDirectory);
			out.write("/container_obj.gif'>");
			out.write(UrlUtil.htmlEncode(topic.getLabel()));
			out.write("</a>");

			out.write("<ul class='collapsed'>");

			ITopic[] topics = topic.getSubtopics();
			for (int i = 0; i < topics.length; i++) {
				generateTopic(topics[i], out);
			}

			out.write("</ul>");
		} else {
			out.write("<img src='");
			out.write(imagesDirectory);
			out.write("/plus.gif' class='h'>");
			out.write("<a href='" + UrlUtil.getHelpURL(topic.getHref()) + "'>");
			out.write("<img src='");
			out.write(imagesDirectory);
			out.write("/topic.gif'>");
			out.write(UrlUtil.htmlEncode(topic.getLabel()));
			out.write("</a>");
		}

		out.write("</li>");
	}

	/**
	 * Generates the HTML code (a tree) for a TOC.
	 * @param toc
	 * @param out
	 * @throws IOException
	 */
	public void generateBasicToc(int toc, Writer out) throws IOException {
		ITopic[] topics = tocs[toc].getTopics();
		for (int i = 0; i < topics.length; i++) {
			generateBasicTopic(topics[i], out);
		}

	}

	private void generateBasicTopic(ITopic topic, Writer out)
		throws IOException {

		out.write("<li>");
		boolean hasNodes = topic.getSubtopics().length > 0;
		if (hasNodes) {
			out.write("<nobr>");
			out.write("<a ");
			if (getSelectedTopicHelpHref().equals(topic.getHref())) {
				out.write("name=\"selectedItem\" ");
			}
			out.write("href='" + UrlUtil.getHelpURL(topic.getHref()) + "'>");
			out.write("<img src='");
			out.write(imagesDirectory);
			out.write("/container_obj.gif' border=0>&nbsp;");
			out.write(UrlUtil.htmlEncode(topic.getLabel()));
			out.write("</a>");
			out.write("</nobr>");

			out.write("<ul>");

			ITopic[] topics = topic.getSubtopics();
			for (int i = 0; i < topics.length; i++) {
				generateBasicTopic(topics[i], out);
			}

			out.write("</ul>");
		} else {
			out.write("<nobr>");
			out.write("<a ");
			if (getSelectedTopicHelpHref().equals(topic.getHref())) {
				out.write("name=\"selectedItem\" ");
			}
			out.write("href='" + UrlUtil.getHelpURL(topic.getHref()) + "'>");
			out.write("<img src='");
			out.write(imagesDirectory);
			out.write("/topic.gif' border=0>&nbsp;");
			out.write(UrlUtil.htmlEncode(topic.getLabel()));
			out.write("</a>");
			out.write("</nobr>");
		}

		out.write("</li>");
	}
	/**
	 * @return String - help form of selected topic URL, or ""
	 */
	private String getSelectedTopicHelpHref() {
		if (topicHelpHref == null) {
			String topic = getSelectedTopic();
			if (topic == null || topic.length() == 0) {
				topicHelpHref = "";
				return topicHelpHref;
			}
			int index = topic.indexOf("/topic/");
			if (index != -1)
				topic = topic.substring(index + 6);
			index = topic.indexOf('?');
			if (index != -1)
				topic = topic.substring(0, index);
			topicHelpHref = topic;
			if (topic == null) {
				topicHelpHref = "";
			}
		}
		return topicHelpHref;
	}
}