/*
 *  Copyright 2005,2006 Fabrice Colin
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Library General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifndef _XAPIAN_ENGINE_H
#define _XAPIAN_ENGINE_H

#include <string>
#include <set>
#include <vector>

#include <xapian.h>

#include "config.h"
#include "SearchEngineInterface.h"
#include "DownloaderFactory.h"

#if !ENABLE_XAPIAN_SPELLING_CORRECTION
// Spelling correction in Xapian 1.0.2 may cause a crash
// See http://www.xapian.org/cgi-bin/bugzilla/show_bug.cgi?id=194
#if XAPIAN_NUM_VERSION > 1000002
#define ENABLE_XAPIAN_SPELLING_CORRECTION 1
#else
#define ENABLE_XAPIAN_SPELLING_CORRECTION 0
#endif
#endif

/// Wraps Xapian's search funtionality.
class XapianEngine : public SearchEngineInterface
{
	public:
		XapianEngine(const std::string &database);
		virtual ~XapianEngine();

		/// Sets the set of documents to limit to.
		virtual bool setLimitSet(const std::set<std::string> &docsSet);

		/// Sets the set of documents to expand from.
		virtual bool setExpandSet(const std::set<std::string> &docsSet);

		/// Runs a query; true if success.
		virtual bool runQuery(QueryProperties& queryProps,
			unsigned int startDoc = 0);

	protected:
		std::string m_databaseName;
		std::string m_limitQuery;
		std::set<std::string> m_expandDocuments;

		bool queryDatabase(Xapian::Database *pIndex, Xapian::Query &query,
			unsigned int startDoc, const QueryProperties &queryProps);

		static Xapian::Query parseQuery(Xapian::Database *pIndex, const QueryProperties &queryProps,
			const string &stemLanguage, DefaultOperator defaultOperator,
			const string &limitQuery, string &correctedFreeQuery, bool minimal = false);

	private:
		XapianEngine(const XapianEngine &other);
		XapianEngine &operator=(const XapianEngine &other);

};

#endif // _XAPIAN_ENGINE_H