/*******************************************************************************
 * RetroShare full text indexing and search implementation based on Xapian     *
 *                                                                             *
 * Copyright (C) 2018-2019 Gioacchino Mazzurco <gio@eigenlab.org>              *
 * Copyright (C) 2019  Asociación Civil Altermundi <info@altermundi.net>       *
 *                                                                             *
 * This program is free software: you can redistribute it and/or modify        *
 * it under the terms of the GNU Affero General Public License version 3 as    *
 * published by the Free Software Foundation.                                  *
 *                                                                             *
 * 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 Affero General Public License for more details.                         *
 *                                                                             *
 * You should have received a copy of the GNU Affero General Public License    *
 * along with this program. If not, see <https://www.gnu.org/licenses/>.       *
 *                                                                             *
 *******************************************************************************/
#pragma once

#include "retroshare/rstypes.h"
#include "util/rsdebug.h"

#include <string>
#include <cstdint>
#include <vector>
#include <xapian.h>
#include <map>
#include <functional>

struct DeepFilesSearchResult
{
	DeepFilesSearchResult() : mWeight(0) {}

	RsFileHash mFileHash;
	double mWeight;
	std::string mSnippet;
};

class DeepFilesIndex
{
public:
	DeepFilesIndex(const std::string& dbPath) : mDbPath(dbPath) {}

	/**
	 * @brief Search indexed files
	 * @param[in] maxResults maximum number of acceptable search results, 0 for
	 * no limits
	 * @return search results count
	 */
	uint32_t search( const std::string& queryStr,
	                 std::vector<DeepFilesSearchResult>& results,
	                 uint32_t maxResults = 100 );

	/**
	 * @return false if file could not be indexed because of error or
	 *	unsupported type, true otherwise.
	 */
	bool indexFile(
	        const std::string& path, const std::string& name,
	        const RsFileHash& hash );

	/**
	 * @brief Remove file entry from database
	 * @return false on error, true otherwise.
	 */
	bool removeFileFromIndex(const RsFileHash& hash);

	static std::string dbDefaultPath();

	using IndexerFunType = std::function<
	uint32_t( const std::string& path, const std::string& name,
	Xapian::TermGenerator& xTG, Xapian::Document& xDoc ) >;

	static bool registerIndexer(
	        int order, const IndexerFunType& indexerFun );

private:
	enum : Xapian::valueno
	{
		/// Used to store RsFileHash of indexed documents
		FILE_HASH_VALUENO,

		/** Used to check if some file need reindex because was indexed with an
		 * older version of the indexer */
		INDEXER_VERSION_VALUENO,

		/** Used to check if some file need reindex because was indexed with an
		 * older version of the indexer */
		INDEXERS_COUNT_VALUENO,

		/// @see Xapian::BAD_VALUENO
		BAD_VALUENO = Xapian::BAD_VALUENO
	};

	const std::string mDbPath;

	/** Storage for indexers function by order */
	static std::multimap<int, IndexerFunType> indexersRegister;

	RS_SET_CONTEXT_DEBUG_LEVEL(1)
};