/**
   * Process list of event objects. Checks whether message source contact already exist for this
   * event object, if yes just update it with the new values (not sure whether we should do this, as
   * it may bring old messages) and if status of provider is changed, init its details, updates its
   * capabilities. It still adds the found messages source contact to the list of the new contacts,
   * as later we will detect this and fire update event. If nothing found a new contact is created.
   *
   * @param res list of event
   * @param cachedRecentMessages list of newly created source contacts or already existed but
   *     updated with corresponding event object
   * @param isStatusChanged whether provider status changed and we are processing
   */
  private void processEventObjects(
      Collection<EventObject> res,
      List<ComparableEvtObj> cachedRecentMessages,
      boolean isStatusChanged) {
    for (EventObject obj : res) {
      ComparableEvtObj oldMsg = findRecentMessage(obj, recentMessages);

      if (oldMsg != null) {
        oldMsg.update(obj); // update

        if (isStatusChanged && recentQuery != null) recentQuery.updateCapabilities(oldMsg, obj);

        // we still add it to cachedRecentMessages
        // later we will find it is duplicate and will fire
        // update event
        if (!cachedRecentMessages.contains(oldMsg)) cachedRecentMessages.add(oldMsg);

        continue;
      }

      oldMsg = findRecentMessage(obj, cachedRecentMessages);

      if (oldMsg == null) {
        oldMsg = new ComparableEvtObj(obj);

        if (isStatusChanged && recentQuery != null) recentQuery.updateCapabilities(oldMsg, obj);

        cachedRecentMessages.add(oldMsg);
      }
    }
  }
  /**
   * Permanently removes locally stored message history for the metacontact, remove any recent
   * contacts if any.
   */
  public void eraseLocallyStoredHistory(MetaContact contact) throws IOException {
    List<ComparableEvtObj> toRemove = null;
    synchronized (recentMessages) {
      toRemove = new ArrayList<ComparableEvtObj>();
      Iterator<Contact> iter = contact.getContacts();
      while (iter.hasNext()) {
        Contact item = iter.next();
        String id = item.getAddress();
        ProtocolProviderService provider = item.getProtocolProvider();

        for (ComparableEvtObj msc : recentMessages) {
          if (msc.getProtocolProviderService().equals(provider)
              && msc.getContactAddress().equals(id)) {
            toRemove.add(msc);
          }
        }
      }

      recentMessages.removeAll(toRemove);
    }
    if (recentQuery != null) {
      for (ComparableEvtObj msc : toRemove) {
        recentQuery.fireContactRemoved(msc);
      }
    }
  }
 /**
  * Indicates that a MetaContact has been modified.
  *
  * @param evt the MetaContactListEvent containing the corresponding contact
  */
 public void metaContactRenamed(MetaContactRenamedEvent evt) {
   for (ComparableEvtObj msc : recentMessages) {
     if (evt.getSourceMetaContact().containsContact(msc.getContact())) {
       if (recentQuery != null) recentQuery.updateContactDisplayName(msc, evt.getNewDisplayName());
     }
   }
 }
  @Override
  public void localUserPresenceChanged(LocalUserChatRoomPresenceChangeEvent evt) {
    if (recentQuery == null) return;

    ComparableEvtObj srcContact = null;

    synchronized (recentMessages) {
      for (ComparableEvtObj msg : recentMessages) {
        if (msg.getRoom() != null && msg.getRoom().equals(evt.getChatRoom())) {
          srcContact = msg;
          break;
        }
      }
    }

    if (srcContact == null) return;

    String eventType = evt.getEventType();

    if (LocalUserChatRoomPresenceChangeEvent.LOCAL_USER_JOINED.equals(eventType)) {
      recentQuery.updateContactStatus(srcContact, ChatRoomPresenceStatus.CHAT_ROOM_ONLINE);
    } else if ((LocalUserChatRoomPresenceChangeEvent.LOCAL_USER_LEFT.equals(eventType)
        || LocalUserChatRoomPresenceChangeEvent.LOCAL_USER_KICKED.equals(eventType)
        || LocalUserChatRoomPresenceChangeEvent.LOCAL_USER_DROPPED.equals(eventType))) {
      recentQuery.updateContactStatus(srcContact, ChatRoomPresenceStatus.CHAT_ROOM_OFFLINE);
    }
  }
  /**
   * Updates contact source contacts with status.
   *
   * @param evt the ContactPresenceStatusChangeEvent describing the status
   */
  @Override
  public void contactPresenceStatusChanged(ContactPresenceStatusChangeEvent evt) {
    if (recentQuery == null) return;

    synchronized (recentMessages) {
      for (ComparableEvtObj msg : recentMessages) {
        if (msg.getContact() != null && msg.getContact().equals(evt.getSourceContact())) {
          recentQuery.updateContactStatus(msg, evt.getNewStatus());
        }
      }
    }
  }
  @Override
  public void supportedOperationSetsChanged(ContactCapabilitiesEvent event) {
    Contact contact = event.getSourceContact();

    if (contact == null) return;

    for (ComparableEvtObj msc : recentMessages) {
      if (contact.equals(msc.getContact())) {
        if (recentQuery != null) recentQuery.updateCapabilities(msc, contact);

        return;
      }
    }
  }
  /**
   * If a contact is renamed update the locally stored message if any.
   *
   * @param evt the <tt>ContactPropertyChangeEvent</tt> containing the source
   */
  @Override
  public void contactModified(ContactPropertyChangeEvent evt) {
    if (!evt.getPropertyName().equals(ContactPropertyChangeEvent.PROPERTY_DISPLAY_NAME)) return;

    Contact contact = evt.getSourceContact();

    if (contact == null) return;

    for (ComparableEvtObj msc : recentMessages) {
      if (contact.equals(msc.getContact())) {
        if (recentQuery != null)
          recentQuery.updateContactDisplayName(msc, contact.getDisplayName());

        return;
      }
    }
  }
  /**
   * Permanently removes locally stored message history for the chatroom, remove any recent contacts
   * if any.
   */
  public void eraseLocallyStoredHistory(ChatRoom room) {
    ComparableEvtObj toRemove = null;
    synchronized (recentMessages) {
      for (ComparableEvtObj msg : recentMessages) {
        if (msg.getRoom() != null && msg.getRoom().equals(room)) {
          toRemove = msg;
          break;
        }
      }

      if (toRemove == null) return;

      recentMessages.remove(toRemove);
    }

    if (recentQuery != null) recentQuery.fireContactRemoved(toRemove);
  }
  /**
   * Updates the contact sources in the recent query if any. Done here in order to sync with
   * recentMessages instance, and to check for already existing instances of contact sources.
   * Normally called from the query.
   */
  public void updateRecentMessages() {
    if (recentQuery == null) return;

    synchronized (recentMessages) {
      List<SourceContact> currentContactsInQuery = recentQuery.getQueryResults();

      for (ComparableEvtObj evtObj : recentMessages) {
        // the contains will use the correct equals method of
        // the object evtObj
        if (!currentContactsInQuery.contains(evtObj)) {
          MessageSourceContact newSourceContact =
              new MessageSourceContact(evtObj.getEventObject(), MessageSourceService.this);
          newSourceContact.initDetails(evtObj.getEventObject());

          recentQuery.addQueryResult(newSourceContact);
        }
      }
    }
  }
  /**
   * Tries to match the event object to already existing ComparableEvtObj in the supplied list.
   *
   * @param obj the object that we will try to match.
   * @param list the list we will search in.
   * @return the found ComparableEvtObj
   */
  private static ComparableEvtObj findRecentMessage(EventObject obj, List<ComparableEvtObj> list) {
    Contact contact = null;
    ChatRoom chatRoom = null;

    if (obj instanceof MessageDeliveredEvent) {
      contact = ((MessageDeliveredEvent) obj).getDestinationContact();
    } else if (obj instanceof MessageReceivedEvent) {
      contact = ((MessageReceivedEvent) obj).getSourceContact();
    } else if (obj instanceof ChatRoomMessageDeliveredEvent) {
      chatRoom = ((ChatRoomMessageDeliveredEvent) obj).getSourceChatRoom();
    } else if (obj instanceof ChatRoomMessageReceivedEvent) {
      chatRoom = ((ChatRoomMessageReceivedEvent) obj).getSourceChatRoom();
    }

    for (ComparableEvtObj evt : list) {
      if ((contact != null && contact.equals(evt.getContact()))
          || (chatRoom != null && chatRoom.equals(evt.getRoom()))) return evt;
    }

    return null;
  }
  /** Adds recent message in history. */
  private void saveRecentMessageToHistory(ComparableEvtObj msc) {
    synchronized (historyID) {
      // and create it
      try {
        History history = getHistory();
        HistoryWriter writer = history.getWriter();

        SimpleDateFormat sdf = new SimpleDateFormat(HistoryService.DATE_FORMAT);

        writer.addRecord(
            new String[] {
              msc.getProtocolProviderService().getAccountID().getAccountUniqueID(),
              msc.getContactAddress(),
              sdf.format(msc.getTimestamp()),
              RECENT_MSGS_VER
            },
            NUMBER_OF_MSGS_IN_HISTORY);
      } catch (IOException ex) {
        logger.error("cannot create recent_messages history", ex);
        return;
      }
    }
  }
  /**
   * A provider has been removed.
   *
   * @param provider the ProtocolProviderService that has been unregistered.
   */
  void handleProviderRemoved(ProtocolProviderService provider) {
    // lets remove the recent messages for this provider, and update
    // with recent messages for the available providers
    synchronized (recentMessages) {
      if (provider != null) {
        List<ComparableEvtObj> removedItems = new ArrayList<ComparableEvtObj>();
        for (ComparableEvtObj msc : recentMessages) {
          if (msc.getProtocolProviderService().equals(provider)) removedItems.add(msc);
        }

        recentMessages.removeAll(removedItems);
        if (!recentMessages.isEmpty())
          oldestRecentMessage = recentMessages.get(recentMessages.size() - 1).getTimestamp();
        else oldestRecentMessage = null;

        if (recentQuery != null) {
          for (ComparableEvtObj msc : removedItems) {
            recentQuery.fireContactRemoved(msc);
          }
        }
      }

      // handleProviderRemoved can be invoked due to stopped
      // history service, if this is the case we do not want to
      // update messages
      if (!this.messageHistoryService.isHistoryLoggingEnabled()) return;

      // lets do the same as we enable provider
      // for all registered providers and finally fire events
      List<ComparableEvtObj> contactsToAdd = new ArrayList<ComparableEvtObj>();
      for (ProtocolProviderService pps : messageHistoryService.getCurrentlyAvailableProviders()) {
        contactsToAdd.addAll(getCachedRecentMessages(pps, true));
      }

      addNewRecentMessages(contactsToAdd);
    }
  }
  /**
   * Handles new events.
   *
   * @param obj the event object
   * @param provider the provider
   * @param id the id of the source of the event
   */
  private void handle(EventObject obj, ProtocolProviderService provider, String id) {
    // check if provider - contact exist update message content
    synchronized (recentMessages) {
      ComparableEvtObj existingMsc = null;
      for (ComparableEvtObj msc : recentMessages) {
        if (msc.getProtocolProviderService().equals(provider)
            && msc.getContactAddress().equals(id)) {
          // update
          msc.update(obj);
          updateRecentMessageToHistory(msc);

          existingMsc = msc;
        }
      }

      if (existingMsc != null) {
        Collections.sort(recentMessages);
        oldestRecentMessage = recentMessages.get(recentMessages.size() - 1).getTimestamp();

        if (recentQuery != null) {
          recentQuery.updateContact(existingMsc, existingMsc.getEventObject());
          recentQuery.fireContactChanged(existingMsc);
        }

        return;
      }

      // if missing create source contact
      // and update recent messages, trim and sort
      MessageSourceContact newSourceContact =
          new MessageSourceContact(obj, MessageSourceService.this);
      newSourceContact.initDetails(obj);
      // we have already checked for duplicate
      ComparableEvtObj newMsg = new ComparableEvtObj(obj);
      recentMessages.add(newMsg);

      Collections.sort(recentMessages);
      oldestRecentMessage = recentMessages.get(recentMessages.size() - 1).getTimestamp();

      // trim
      List<ComparableEvtObj> removedItems = null;
      if (recentMessages.size() > numberOfMessages) {
        removedItems =
            new ArrayList<ComparableEvtObj>(
                recentMessages.subList(numberOfMessages, recentMessages.size()));

        recentMessages.removeAll(removedItems);
      }

      // save
      saveRecentMessageToHistory(newMsg);

      // no query nothing to fire
      if (recentQuery == null) return;

      // now fire
      if (removedItems != null) {
        for (ComparableEvtObj msc : removedItems) {
          recentQuery.fireContactRemoved(msc);
        }
      }

      recentQuery.addQueryResult(newSourceContact);
    }
  }
  /**
   * Add the ComparableEvtObj, newly added will fire new, for existing fire update and when trimming
   * the list to desired length fire remove for those that were removed
   *
   * @param contactsToAdd
   */
  private void addNewRecentMessages(List<ComparableEvtObj> contactsToAdd) {
    // now find object to fire new, and object to fire remove
    // let us find duplicates and fire update
    List<ComparableEvtObj> duplicates = new ArrayList<ComparableEvtObj>();
    for (ComparableEvtObj msgToAdd : contactsToAdd) {
      if (recentMessages.contains(msgToAdd)) {
        duplicates.add(msgToAdd);

        // save update
        updateRecentMessageToHistory(msgToAdd);
      }
    }
    recentMessages.removeAll(duplicates);

    // now contacts to add has no duplicates, add them all
    boolean changed = recentMessages.addAll(contactsToAdd);

    if (changed) {
      Collections.sort(recentMessages);

      if (recentQuery != null) {
        for (ComparableEvtObj obj : duplicates)
          recentQuery.updateContact(obj, obj.getEventObject());
      }
    }

    if (!recentMessages.isEmpty())
      oldestRecentMessage = recentMessages.get(recentMessages.size() - 1).getTimestamp();

    // trim
    List<ComparableEvtObj> removedItems = null;
    if (recentMessages.size() > numberOfMessages) {
      removedItems =
          new ArrayList<ComparableEvtObj>(
              recentMessages.subList(numberOfMessages, recentMessages.size()));

      recentMessages.removeAll(removedItems);
    }

    if (recentQuery != null) {
      // now fire, removed for all that were in the list
      // and now are removed after trim
      if (removedItems != null) {
        for (ComparableEvtObj msc : removedItems) {
          if (!contactsToAdd.contains(msc)) recentQuery.fireContactRemoved(msc);
        }
      }

      // fire new for all that were added, and not removed after trim
      for (ComparableEvtObj msc : contactsToAdd) {
        if ((removedItems == null || !removedItems.contains(msc)) && !duplicates.contains(msc)) {
          MessageSourceContact newSourceContact =
              new MessageSourceContact(msc.getEventObject(), MessageSourceService.this);
          newSourceContact.initDetails(msc.getEventObject());

          recentQuery.addQueryResult(newSourceContact);
        }
      }

      // if recent messages were changed, indexes have change lets
      // fire event for the last element which will reorder the whole
      // group if needed.
      if (changed) recentQuery.fireContactChanged(recentMessages.get(recentMessages.size() - 1));
    }
  }
    /**
     * Compares two ComparableEvtObj.
     *
     * @param o the object to compare with
     * @return 0, less than zero, greater than zero, if equals, less or greater.
     */
    @Override
    public int compareTo(ComparableEvtObj o) {
      if (o == null || o.getTimestamp() == null) return 1;

      return o.getTimestamp().compareTo(getTimestamp());
    }