/**
   * Returns the index of the source contact, in the list of recent messages.
   *
   * @param messageSourceContact
   * @return
   */
  int getIndex(MessageSourceContact messageSourceContact) {
    synchronized (recentMessages) {
      for (int i = 0; i < recentMessages.size(); i++)
        if (recentMessages.get(i).equals(messageSourceContact)) return i;

      return -1;
    }
  }
  /**
   * 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));
    }
  }