/**
 * Copyright © 2001 The JA-SIG Collaborative.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the JA-SIG Collaborative
 *    (http://www.jasig.org/)."
 *
 * THIS SOFTWARE IS PROVIDED BY THE JA-SIG COLLABORATIVE "AS IS" AND ANY
 * EXPRESSED 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 JA-SIG COLLABORATIVE OR
 * ITS 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.
 *
 */

package  org.jasig.portal;

import java.util.Date;
import java.util.Iterator;

import org.apache.xpath.XPathAPI;
import org.jasig.portal.groups.IEntity;
import org.jasig.portal.groups.IEntityGroup;
import org.jasig.portal.groups.IGroupMember;
import org.jasig.portal.properties.PropertiesManager;
import org.jasig.portal.security.IPerson;
import org.jasig.portal.services.GroupService;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jasig.portal.utils.CommonUtils;
import org.jasig.portal.utils.DocumentFactory;
import org.jasig.portal.utils.SmartCache;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

/**
 * Provides a list of summarized channel statistics. 
 * @author rtwigg@uccs.edu, adapted from ChannelRegistryManager
 */
public class ChannelStatisticsManager {
    
    private static final Log log = LogFactory.getLog(ChannelStatisticsManager.class);
    
  protected static final IChannelStatisticsStore css = ChannelStatisticsStoreFactory.getChannelStatisticsStoreImpl();
  protected static final IChannelRegistryStore crs = ChannelRegistryStoreFactory.getChannelRegistryStoreImpl();

  // Cache timeout properties
  protected static final int statisticsCacheTimeout = PropertiesManager.getPropertyAsInt("org.jasig.portal.ChannelStatisticsManager.channel_statistics_cache_timeout");

  // I18n property
  protected static final boolean localeAware = PropertiesManager.getPropertyAsBoolean("org.jasig.portal.i18n.LocaleManager.locale_aware");

  // Caches
  protected static final SmartCache channelStatisticsCache = new SmartCache(statisticsCacheTimeout);

  // Cache keys
  private static final String CHANNEL_STATISTICS_CACHE_KEY = "channelStatisticsCacheKey";

  // Permission constants
  private static final String FRAMEWORK_OWNER = "UP_FRAMEWORK";
  private static final String SUBSCRIBER_ACTIVITY = "SUBSCRIBE";
  private static final String GRANT_PERMISSION_TYPE = "GRANT";

  /**
   * Returns a copy of the channel statistics listing as a Document.
   * This document is not filtered according to a user's channel permissions.
   * For a filtered list, see  <code>getChannelSummaryStats(IPerson person)</code>
   * @return a copy of the channel registry as a Document
   */
  public static Document getChannelStatsListing() throws PortalException {
    Document channelStatsListing = (Document)channelStatisticsCache.get(CHANNEL_STATISTICS_CACHE_KEY);
    if (channelStatsListing == null) {
      // Channel stats listing has expired, so get it and cache it
      try {
        channelStatsListing = getChannelStatsListingXML();
log.info("RT: Got the channel stats listing in XML");
      } catch (Exception e) {
        throw new PortalException(e);
      }

      if (channelStatsListing != null) {
        channelStatisticsCache.put(CHANNEL_STATISTICS_CACHE_KEY, channelStatsListing);
        log.info( "Caching channel stats listing.");
      }
    }
    return channelStatsListing;
  }


  /**
   * Returns an XML document which describes the channel statistics listing.
   * @return doc the channel statistics listing document
   * @throws java.lang.Exception
   */
  public static Document getChannelStatsListingXML() throws Exception {
    Document doc = DocumentFactory.getNewDocument();
    Element statsListing = doc.createElement("statsListing");
    doc.appendChild(statsListing);

    IEntityGroup channelCategoriesGroup = GroupService.getDistinguishedGroup(GroupService.CHANNEL_CATEGORIES);
    processGroupsRecursively(channelCategoriesGroup, doc, statsListing);

    return doc;
  }

  private static void processGroupsRecursively(IEntityGroup group,
    Document owner, Element parentGroup) throws Exception {
    Date now = new Date();
    Iterator iter = group.getMembers();
    while (iter.hasNext()) {
      IGroupMember member = (IGroupMember)iter.next();
      if (member.isGroup()) {
        IEntityGroup memberGroup = (IEntityGroup)member;
        String key = memberGroup.getKey();
        String name = memberGroup.getName();
        String description = memberGroup.getDescription();

        // Create category element and append it to its parent
        Element categoryE = owner.createElement("category");
        categoryE.setAttribute("ID", "cat" + key);
        categoryE.setAttribute("name", name);
        categoryE.setAttribute("description", description);
        parentGroup.appendChild(categoryE);
        processGroupsRecursively(memberGroup, owner, categoryE);
      } else {
        IEntity channelStatsMember = (IEntity)member;
        int channelPublishId = CommonUtils.parseInt(channelStatsMember.getKey());
        if ( channelPublishId > 0 ) {
          ChannelStatistics channelStats = css.getChannelStatistics(channelPublishId);
          if (channelStats != null) {
            Element channelStatsE = channelStats.getDocument(owner, "chan" + channelPublishId);
            channelStatsE = (Element)owner.importNode(channelStatsE, true);
            parentGroup.appendChild(channelStatsE);
          }
        }
      }
    }
  }

  /**
   * Looks in channel statistics listing for a channel element matching the
   * given channel ID.
   * @param channelPublishId the channel publish id
   * @return the channel element matching specified channel publish id
   * @throws PortalException
   */
  public static Element getChannelDetails (String channelPublishId) throws PortalException {
    Document channelStatsListing = getChannelStatsListing();
    Element channelStatsE = null;
    try {
      // This is unfortunately dependent on Xalan 2.  Is there a way to use a standard interface?
      channelStatsE = (Element)XPathAPI.selectSingleNode(channelStatsListing, "(//channelStats[@ID = '" + channelPublishId + "'])[1]");
    } catch (javax.xml.transform.TransformerException te) {
      throw new GeneralRenderingException("Not able to find channel " + channelPublishId + " within channel stats listing: " + te.getMessageAndLocation());
    }
    return channelStatsE;
  }

  /**
   * Looks in channel registry for a channel element matching the
   * given channel ID.
   * @param channelPublishId the channel publish ID
   * @return the channel element matching chanID
   * @throws org.jasig.portal.PortalException
   */
  public static NodeList getCategories(String channelPublishId) throws PortalException {
    Document channelStatsListing = (Document)channelStatisticsCache.get(CHANNEL_STATISTICS_CACHE_KEY);
    NodeList categories = null;
    try {
      // This is unfortunately dependent on Xalan 2.  Is there a way to use a standard interface?
      categories = (NodeList)XPathAPI.selectNodeList(channelStatsListing, "//category[channel/@ID = '" + channelPublishId + "']");
    } catch (javax.xml.transform.TransformerException te) {
      throw new GeneralRenderingException("Not able to find channel " + channelPublishId + " within channel stats listing: " + te.getMessageAndLocation());
    }
    return categories;
  }


}