/*
    * Copyright 2003 - 2013 The eFaps Team
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   * Revision:        $Rev$
   * Last Changed:    $Date$
   * Last Changed By: $Author$
   */
  
  package org.efaps.message;
  
  import java.sql.PreparedStatement;
  import java.sql.ResultSet;
  import java.sql.SQLException;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.UUID;
  
  import org.efaps.admin.datamodel.Status;
  import org.efaps.db.Context;
  import org.efaps.db.transaction.ConnectionResource;
  import org.efaps.util.EFapsException;
  import org.quartz.Job;
  import org.quartz.JobExecutionContext;
  import org.quartz.JobExecutionException;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Holds the status of the messages including their count.
   *
   * @author The eFaps Team
   * @version $Id$
   */
  public class MessageStatusHolder
      implements Job
  {
      /**
       * Logging instance used in this class.
       */
      private static final Logger LOG = LoggerFactory.getLogger(MessageStatusHolder.class);
  
      /**
       * basis select.
       */
      private static final String SELECT = "SELECT DISTINCT userid, count(*) "
          + "FROM t_msg2user WHERE status = ? GROUP BY userid";
  
      /**
       * Cache used for the MessageStatus.
       */
      private static final MsgCache CACHE = new MsgCache();
  
      /**
       * Execute the job.
       * @param _context JobExecutionContext
       * @throws JobExecutionException on error
       */
      @Override
      public void execute(final JobExecutionContext _context)
          throws JobExecutionException
      {
          MessageStatusHolder.CACHE.update();
      }
  
      /**
       * has the given user read messages.
       * @param _userId   user id the status is wanted for
       * @return true if unread exist
       */
      public static boolean hasReadMsg(final Long _userId)
      {
          return MessageStatusHolder.CACHE.userID2Read.containsKey(_userId);
      }
  
      /**
       * Count of read messages.
       * @param _userId  user id the count is wanted for
       * @return count of read messages
       */
      public static int getReadCount(final Long _userId)
      {
          int ret = 0;
          if (MessageStatusHolder.CACHE.userID2Read.containsKey(_userId)) {
              ret = MessageStatusHolder.CACHE.userID2Read.get(_userId);
          }
          return ret;
      }
 
     /**
      * has the given user unread messages.
      * @param _userId   user id the status is wanted for
      * @return true if unread exist
      */
     public static boolean hasUnreadMsg(final Long _userId)
     {
         return MessageStatusHolder.CACHE.userID2UnRead.containsKey(_userId);
     }
 
     /**
      * Count of unread messages.
      * @param _userId  user id the count is wanted for
      * @return count of unread messages
      */
     public static int getUnReadCount(final Long _userId)
     {
         int ret = 0;
         if (MessageStatusHolder.CACHE.userID2UnRead.containsKey(_userId)) {
             ret = MessageStatusHolder.CACHE.userID2UnRead.get(_userId);
         }
         return ret;
     }
 
     /**
      * Thread save cache.
      */
     private static final class MsgCache
     {
         /**
          * The map holds all cached data instances by Id. Because of the
          * double-checked locking idiom, the instance variable is defined
          * <i>volatile</i>.
          */
         private volatile Map<Long, Integer> userID2UnRead = null;
 
         /**
          * The map holds all cached data instances by Id. Because of the
          * double-checked locking idiom, the instance variable is defined
          * <i>volatile</i>.
          */
         private volatile Map<Long, Integer> userID2Read = null;
 
         /**
          * Constructor setting empty map.
          */
         private MsgCache()
         {
             this.userID2UnRead = new HashMap<Long,  Integer>();
             this.userID2Read = new HashMap<Long,  Integer>();
         }
 
         /**
          * Update the MessageStatus.
          */
         public void update()
         {
             ConnectionResource con = null;
             boolean abort = true;
             try {
                 con = Context.getThreadContext().getConnectionResource();
 
                 final Map<Long, Integer> unread = new HashMap<Long, Integer>();
                 final Map<Long, Integer> read = new HashMap<Long, Integer>();
 
                 final PreparedStatement stmt = con.getConnection().prepareStatement(MessageStatusHolder.SELECT);
                 stmt.setLong(1, Status.find(UUID.fromString("87b82fee-69d3-4e45-aced-0d57c6a0cd1d"), "Unread").getId());
 
                 final ResultSet rs = stmt.executeQuery();
 
                 while (rs.next()) {
                     final long id = rs.getLong(1);
                     final Integer count = rs.getInt(2);
                     unread.put(id, count);
                 }
                 rs.close();
 
                 stmt.setLong(1, Status.find(UUID.fromString("87b82fee-69d3-4e45-aced-0d57c6a0cd1d"), "Read").getId());
                 final ResultSet rs2 = stmt.executeQuery();
 
                 while (rs2.next()) {
                     final long id = rs2.getLong(1);
                     final Integer count = rs2.getInt(2);
                     read.put(id, count);
                 }
                 rs2.close();
                 stmt.close();
                 con.commit();
                 this.userID2UnRead = unread;
                 this.userID2Read = read;
                 abort = false;
             } catch (final EFapsException e) {
                 MessageStatusHolder.LOG.error("EFapsException");
             } catch (final IllegalStateException e) {
                 MessageStatusHolder.LOG.error("IllegalStateException");
             } catch (final SQLException e) {
                 MessageStatusHolder.LOG.error("SQLException");
             } finally {
                 if (abort && con != null) {
                     try {
                         con.abort();
                     } catch (final EFapsException e) {
                         MessageStatusHolder.LOG.error("EFapsException");
                     }
                 }
             }
         }
     }
 }