/**
 * The class responsible for managing a backend.
 * The implementation of this abstract class contains
 * the complete database handling.
 *
 * Copyright (c) 2002 by Stefan Eilers (Eilers.Stefan@epost.de)
 * Copyright (c) 2002 by Holger Freyther (zecke@handhelds.org)
 *
 * =====================================================================
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU Library General Public
 *      License as published by the Free Software Foundation;
 *      either version 2 of the License, or (at your option) any later
 *      version.
 * =====================================================================
 * ToDo: Define enum for query settings
 * =====================================================================
 * Version: $Id$
 * =====================================================================
 * History:
 * $Log$
 * Revision 1.7  2004/02/19 02:05:37  zecke
 * Add notes for API fixes and BC stuff
 *
 * Revision 1.6  2003/08/01 12:30:16  eilers
 * Merging changes from BRANCH_1_0 to HEAD
 *
 * Revision 1.5.4.1  2003/06/30 14:34:19  eilers
 * Patches from Zecke:
 * Fixing and cleaning up extraMap handling
 * Adding d_ptr for binary compatibility in the future
 *
 * Revision 1.5  2003/04/13 18:07:10  zecke
 * More API doc
 * QString -> const QString&
 * QString = 0l -> QString::null
 *
 * Revision 1.4  2002/11/13 14:14:51  eilers
 * Added sorted for Contacts..
 *
 * Revision 1.3  2002/11/01 15:10:42  eilers
 * Added regExp-search in database for all fields in a contact.
 *
 * Revision 1.2  2002/10/07 17:34:24  eilers
 * added OBackendFactory for advanced backend access
 *
 * Revision 1.1  2002/09/27 17:11:44  eilers
 * Added API for accessing the Contact-Database ! It is compiling, but
 * please do not expect that anything is working !
 * I will debug that stuff in the next time ..
 * Please read README_COMPILE for compiling !
 *
 * =====================================================================
 *
 */

#ifndef _OCONTACTACCESSBACKEND_H_
#define _OCONTACTACCESSBACKEND_H_

#include "ocontact.h"
#include "opimaccessbackend.h"

#include <qregexp.h>

/**
 * This class represents the interface of all Contact Backends.
 * Derivates of this class will be used to access the contacts.
 * As implementation currently XML and vCard exist. This class needs to be implemented
 * if you want to provide your own storage.
 * In all queries a list of uids is passed on instead of loading the actual record!
 *
 * @see OContactAccessBackend_VCard
 * @see OContactAccessBackend_XML
 */
class OContactAccessBackend: public OPimAccessBackend<OContact> {
 public:
	/**
	 * @todo make non line in regard to BC guide of KDE
	 */
	OContactAccessBackend() {}
	/**
	 * @todo make non inline in regard to the BC guide of KDE
	 */
	virtual ~OContactAccessBackend() {}


	/**
         * Return if database was changed externally.
	 * This may just make sense on file based databases like a XML-File.
	 * It is used to prevent to overwrite the current database content
	 * if the file was already changed by something else !
	 * If this happens, we have to reload before save our data.
	 * If we use real databases, this should be handled by the database
	 * management system themselve, therefore this function should always return false in
	 * this case. It is not our problem to handle this conflict ...
	 * @return <i>true</i> if the database was changed and if save without reload will
	 * be dangerous. <i>false</i> if the database was not changed or it is save to write
	 * in this situation.
	 */
	virtual bool wasChangedExternally() = 0;

	virtual QArray<int> matchRegexp(  const QRegExp &r ) const = 0;

	/**
         *  Return all possible settings.
	 *  @return All settings provided by the current backend
	 * (i.e.: query_WildCards & query_IgnoreCase)
	 */
	virtual const uint querySettings() = 0;

	/**
         * Check whether settings are correct.
	 * @return <i>true</i> if the given settings are correct and possible.
	 */
	virtual bool hasQuerySettings (uint querySettings) const = 0;

        /**
         * FIXME!!!
         * Returns a sorted list of records either ascendinf or descending for a giving criteria and category
         */
        virtual QArray<int> sorted( bool ascending, int sortOrder, int sortFilter, int cat ) = 0;
	
	
private:
	class Private;
	Private *d;
};
#endif