main-db.cpp

/*
 * main-db.cpp
 * Copyright (C) 2010-2017 Belledonne Communications SARL
 *
 * 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 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include <algorithm>
#include <ctime>

#ifdef SOCI_ENABLED
	#include <soci/soci.h>
#endif // ifdef SOCI_ENABLED

#include "linphone/utils/utils.h"

#include "chat/chat-message/chat-message-p.h"
#include "chat/chat-room/chat-room-p.h"
#include "chat/chat-room/client-group-chat-room.h"
#include "chat/chat-room/server-group-chat-room.h"
#include "conference/participant-p.h"
#include "content/content-type.h"
#include "content/content.h"
#include "core/core-p.h"
#include "db/session/db-session-provider.h"
#include "event-log/event-log-p.h"
#include "event-log/events.h"
#include "logger/logger.h"
#include "main-db-key-p.h"
#include "main-db-p.h"

// =============================================================================

// See: http://soci.sourceforge.net/doc/3.2/exchange.html
// Part: Object lifetime and immutability

// -----------------------------------------------------------------------------

using namespace std;

LINPHONE_BEGIN_NAMESPACE

// -----------------------------------------------------------------------------

MainDb::MainDb (const shared_ptr<Core> &core) : AbstractDb(*new MainDbPrivate), CoreAccessor(core) {}

#ifdef SOCI_ENABLED

// -----------------------------------------------------------------------------
// Soci backend.
// -----------------------------------------------------------------------------

	template<typename T>
	struct EnumToSql {
		T first;
		const char *second;
	};

	template<typename T>
	static constexpr const char *mapEnumToSql (const EnumToSql<T> enumToSql[], size_t n, T key) {
		return n == 0 ? "" : (
			enumToSql[n - 1].first == key ? enumToSql[n - 1].second : mapEnumToSql(enumToSql, n - 1, key)
		);
	}

	static constexpr EnumToSql<MainDb::Filter> eventFilterToSql[] = {
		{ MainDb::ConferenceCallFilter, "3, 4" },
		{ MainDb::ConferenceChatMessageFilter, "5" },
		{ MainDb::ConferenceInfoFilter, "1, 2, 6, 7, 8, 9, 10, 11, 12" }
	};

	static constexpr const char *mapEventFilterToSql (MainDb::Filter filter) {
		return mapEnumToSql(
			eventFilterToSql, sizeof eventFilterToSql / sizeof eventFilterToSql[0], filter
		);
	}

// -----------------------------------------------------------------------------

	static string buildSqlEventFilter (
		const list<MainDb::Filter> &filters,
		MainDb::FilterMask mask,
		const string &condKeyWord = "WHERE"
	) {
		L_ASSERT(
			find_if(filters.cbegin(), filters.cend(), [](const MainDb::Filter &filter) {
				return filter == MainDb::NoFilter;
			}) == filters.cend()
		);

		if (mask == MainDb::NoFilter)
			return "";

		bool isStart = true;
		string sql;
		for (const auto &filter : filters) {
			if (!(mask & filter))
				continue;

			if (isStart) {
				isStart = false;
				sql += " " + condKeyWord + " type IN (";
			} else
				sql += ", ";
			sql += mapEventFilterToSql(filter);
		}

		if (!isStart)
			sql += ") ";

		return sql;
	}

// -----------------------------------------------------------------------------

	long long MainDbPrivate::resolveId (const soci::row &row, int col) const {
		L_Q();
		// See: http://soci.sourceforge.net/doc/master/backends/
		// `row id` is not supported by soci on Sqlite3. It's necessary to cast id to int...
		return q->getBackend() == AbstractDb::Sqlite3
			? static_cast<long long>(row.get<int>(0))
			: static_cast<long long>(row.get<unsigned long long>(0));
	}

	long long MainDbPrivate::insertSipAddress (const string &sipAddress) {
		L_Q();
		soci::session *session = dbSession.getBackendSession<soci::session>();

		long long id = selectSipAddressId(sipAddress);
		if (id >= 0)
			return id;

		lInfo() << "Insert new sip address in database: `" << sipAddress << "`.";
		*session << "INSERT INTO sip_address (value) VALUES (:sipAddress)", soci::use(sipAddress);
		return q->getLastInsertId();
	}

	void MainDbPrivate::insertContent (long long eventId, const Content &content) {
		L_Q();
		soci::session *session = dbSession.getBackendSession<soci::session>();

		const long long &contentTypeId = insertContentType(content.getContentType().asString());
		const string &body = content.getBodyAsString();
		*session << "INSERT INTO chat_message_content (event_id, content_type_id, body) VALUES"
			"  (:eventId, :contentTypeId, :body)", soci::use(eventId), soci::use(contentTypeId),
			soci::use(body);

		const long long &messageContentId = q->getLastInsertId();
		if (content.getContentType().isFile()) {
			const FileContent &fileContent = static_cast<const FileContent &>(content);
			const string &fileName = fileContent.getFileName();
			const size_t &fileSize = fileContent.getFileSize();
			const string &filePath = fileContent.getFilePath();
			*session << "INSERT INTO chat_message_file_content (chat_message_content_id, name, size, path) VALUES "
				" (:contentId, :name, :size, :path)",
				soci::use(messageContentId), soci::use(fileName), soci::use(fileSize), soci::use(filePath);
		}

		for (const auto &appData : content.getAppDataMap())
			*session << "INSERT INTO chat_message_content_app_data (chat_message_content_id, name, data) VALUES"
				"  (:messageContentId, :name, :data)",
				soci::use(messageContentId), soci::use(appData.first), soci::use(appData.second);
	}

	void MainDbPrivate::updateContent (long long eventId, long long messageContentId, const Content &content) {
		soci::session *session = dbSession.getBackendSession<soci::session>();

		const long long &contentTypeId = insertContentType(content.getContentType().asString());
		const string &body = content.getBodyAsString();
		*session << "UPDATE chat_message_content SET content_type_id=:contentTypeId, body=:body WHERE event_id=:eventId",
			soci::use(contentTypeId), soci::use(body), soci::use(eventId);

		for (const auto &appData : content.getAppDataMap())
			*session << "UPDATE chat_message_content_app_data SET name=:name, data=:data WHERE chat_message_content_id=:messageContentId",
				soci::use(appData.first), soci::use(appData.second), soci::use(messageContentId);
	}

	void MainDbPrivate::removeContentsForChatMessageEvent (long long eventId) {
		soci::session *session = dbSession.getBackendSession<soci::session>();

		*session << "DELETE FROM chat_message_content WHERE event_id=:eventId", soci::use(eventId);

		//TODO: remove file content if exists
		//*session << "DELETE FROM chat_message_file_content WHERE chat_message_content_id=:messageContentId", soci::use(messageContentId);

		//TODO: remove contents' app_data
		//*session << "DELETE FROM chat_message_content_app_data WHERE chat_message_content_id=:messageContentId", soci::use(messageContentId);
	}

	long long MainDbPrivate::insertContentType (const string &contentType) {
		L_Q();
		soci::session *session = dbSession.getBackendSession<soci::session>();

		long long id;
		*session << "SELECT id FROM content_type WHERE value = :contentType", soci::use(contentType), soci::into(id);
		if (session->got_data())
			return id;

		lInfo() << "Insert new content type in database: `" << contentType << "`.";
		*session << "INSERT INTO content_type (value) VALUES (:contentType)", soci::use(contentType);
		return q->getLastInsertId();
	}

	long long MainDbPrivate::insertBasicChatRoom (
		long long peerSipAddressId,
		long long localSipAddressId,
		const tm &creationTime
	) {
		L_Q();

		soci::session *session = dbSession.getBackendSession<soci::session>();

		long long id = selectChatRoomId(peerSipAddressId, localSipAddressId);
		if (id >= 0)
			return id;

		static const int capabilities = static_cast<int>(ChatRoom::Capabilities::Basic);
		lInfo() << "Insert new chat room in database: (peer=" << peerSipAddressId <<
			", local=" << localSipAddressId << ", capabilities=" << capabilities << ").";
		*session << "INSERT INTO chat_room ("
			"  peer_sip_address_id, local_sip_address_id, creation_time, last_update_time, capabilities"
			") VALUES (:peerSipAddressId, :localSipAddressId, :creationTime, :lastUpdateTime, :capabilities)",
			soci::use(peerSipAddressId), soci::use(localSipAddressId), soci::use(creationTime), soci::use(creationTime),
			soci::use(capabilities);

		return q->getLastInsertId();
	}

	long long MainDbPrivate::insertChatRoom (const shared_ptr<ChatRoom> &chatRoom) {
		L_Q();

		soci::session *session = dbSession.getBackendSession<soci::session>();

		const ChatRoomId &chatRoomId = chatRoom->getChatRoomId();
		const long long &peerSipAddressId = insertSipAddress(chatRoomId.getPeerAddress().asString());
		const long long &localSipAddressId = insertSipAddress(chatRoomId.getLocalAddress().asString());

		long long id = selectChatRoomId(peerSipAddressId, localSipAddressId);
		if (id >= 0) {
			lWarning() << "Unable to insert chat room (it already exists): (peer=" << peerSipAddressId <<
				", local=" << localSipAddressId << ").";
			return id;
		}

		lInfo() << "Insert new chat room in database: (peer=" << peerSipAddressId <<
			", local=" << localSipAddressId << ").";

		const tm &creationTime = Utils::getTimeTAsTm(chatRoom->getCreationTime());
		const int &capabilities = static_cast<int>(chatRoom->getCapabilities());
		const string &subject = chatRoom->getSubject();
		const int &flags = chatRoom->hasBeenLeft();
		*session << "INSERT INTO chat_room ("
			"  peer_sip_address_id, local_sip_address_id, creation_time, last_update_time, capabilities, subject, flags"
			") VALUES (:peerSipAddressId, :localSipAddressId, :creationTime, :lastUpdateTime, :capabilities, :subject, :flags)",
			soci::use(peerSipAddressId), soci::use(localSipAddressId), soci::use(creationTime), soci::use(creationTime),
			soci::use(capabilities), soci::use(subject), soci::use(flags);

		id = q->getLastInsertId();

		if (!chatRoom->canHandleParticipants())
			return id;

		// Do not add 'me' when creating a server-group-chat-room.
		if (chatRoomId.getLocalAddress() != chatRoomId.getPeerAddress()) {
			shared_ptr<Participant> me = chatRoom->getMe();
			long long meId = insertChatRoomParticipant(
				id,
				insertSipAddress(me->getAddress().asString()),
				me->isAdmin()
			);
			for (const auto &device : me->getPrivate()->getDevices())
				insertChatRoomParticipantDevice(meId, insertSipAddress(device->getAddress().asString()));
		}

		for (const auto &participant : chatRoom->getParticipants()) {
			long long participantId = insertChatRoomParticipant(
				id,
				insertSipAddress(participant->getAddress().asString()),
				participant->isAdmin()
			);
			for (const auto &device : participant->getPrivate()->getDevices())
				insertChatRoomParticipantDevice(participantId, insertSipAddress(device->getAddress().asString()));
		}

		return id;
	}

	long long MainDbPrivate::insertChatRoomParticipant (long long chatRoomId, long long sipAddressId, bool isAdmin) {
		L_Q();

		long long id = -1;
		soci::session *session = dbSession.getBackendSession<soci::session>();
		*session << "SELECT id from chat_room_participant"
			"  WHERE chat_room_id = :chatRoomId AND participant_sip_address_id = :sipAddressId",
			soci::into(id), soci::use(chatRoomId), soci::use(sipAddressId);

		if (id >= 0) {
			// See: https://stackoverflow.com/a/15299655 (cast to reference)
			*session << "UPDATE chat_room_participant SET is_admin = :isAdmin"
				"  WHERE id = :id",
				soci::use(static_cast<const int &>(isAdmin)), soci::use(id);
			return id;
		}

		lInfo() << "Insert new chat room participant in database: `" << sipAddressId << "` (isAdmin=" << isAdmin << ").";
		*session << "INSERT INTO chat_room_participant (chat_room_id, participant_sip_address_id, is_admin)"
			"  VALUES (:chatRoomId, :sipAddressId, :isAdmin)",
			soci::use(chatRoomId), soci::use(sipAddressId), soci::use(static_cast<const int &>(isAdmin));

		return q->getLastInsertId();
	}

	void MainDbPrivate::insertChatRoomParticipantDevice (long long participantId, long long sipAddressId) {
		soci::session *session = dbSession.getBackendSession<soci::session>();
		long long count;
		*session << "SELECT COUNT(*) FROM chat_room_participant_device"
			"  WHERE chat_room_participant_id = :participantId"
			"  AND participant_device_sip_address_id = :sipAddressId",
			soci::into(count), soci::use(participantId), soci::use(sipAddressId);
		if (count)
			return;

		lInfo() << "Insert new chat room participant device in database: `" << sipAddressId << "`.";
		*session << "INSERT INTO chat_room_participant_device (chat_room_participant_id, participant_device_sip_address_id)"
			"  VALUES (:participantId, :sipAddressId)",
			soci::use(participantId), soci::use(sipAddressId);
	}

	void MainDbPrivate::insertChatMessageParticipant (long long eventId, long long sipAddressId, int state) {
		soci::session *session = dbSession.getBackendSession<soci::session>();
		soci::statement statement = (
			session->prepare << "UPDATE chat_message_participant SET state = :state"
				"  WHERE event_id = :eventId AND participant_sip_address_id = :sipAddressId",
				soci::use(state), soci::use(eventId), soci::use(sipAddressId)
		);
		statement.execute(true);
		if (statement.get_affected_rows() == 0 && state != static_cast<int>(ChatMessage::State::Displayed))
			*session << "INSERT INTO chat_message_participant (event_id, participant_sip_address_id, state)"
				"  VALUES (:eventId, :sipAddressId, :state)",
				soci::use(eventId), soci::use(sipAddressId), soci::use(state);
	}

	long long MainDbPrivate::selectSipAddressId (const string &sipAddress) const {
		soci::session *session = dbSession.getBackendSession<soci::session>();

		long long id;
		*session << "SELECT id FROM sip_address WHERE value = :sipAddress", soci::use(sipAddress), soci::into(id);
		return session->got_data() ? id : -1;
	}

	long long MainDbPrivate::selectChatRoomId (long long peerSipAddressId, long long localSipAddressId) const {
		soci::session *session = dbSession.getBackendSession<soci::session>();

		long long id;
		*session << "SELECT id FROM chat_room"
			"  WHERE peer_sip_address_id = :peerSipAddressId AND local_sip_address_id = :localSipAddressId",
			soci::use(peerSipAddressId), soci::use(localSipAddressId), soci::into(id);
		return session->got_data() ? id : -1;
	}

	long long MainDbPrivate::selectChatRoomId (const ChatRoomId &chatRoomId) const {
		long long peerSipAddressId = selectSipAddressId(chatRoomId.getPeerAddress().asString());
		if (peerSipAddressId < 0)
			return -1;

		long long localSipAddressId = selectSipAddressId(chatRoomId.getLocalAddress().asString());
		if (localSipAddressId < 0)
			return -1;

		return selectChatRoomId(peerSipAddressId, localSipAddressId);
	}

	void MainDbPrivate::deleteChatRoomParticipant (long long chatRoomId, long long participantSipAddressId) {
		soci::session *session = dbSession.getBackendSession<soci::session>();
		*session << "DELETE FROM chat_room_participant"
			"  WHERE chat_room_id = :chatRoomId AND participant_sip_address_id = :participantSipAddressId",
			soci::use(chatRoomId), soci::use(participantSipAddressId);
	}

// -----------------------------------------------------------------------------

	shared_ptr<EventLog> MainDbPrivate::selectGenericConferenceEvent (
		long long eventId,
		EventLog::Type type,
		time_t creationTime,
		const ChatRoomId &chatRoomId
	) const {
		shared_ptr<EventLog> eventLog;

		switch (type) {
			case EventLog::Type::None:
				return nullptr;

			case EventLog::Type::ConferenceCreated:
			case EventLog::Type::ConferenceTerminated:
				eventLog = selectConferenceEvent(eventId, type, creationTime, chatRoomId);
				break;

			case EventLog::Type::ConferenceCallStart:
			case EventLog::Type::ConferenceCallEnd:
				eventLog = selectConferenceCallEvent(eventId, type, creationTime, chatRoomId);
				break;

			case EventLog::Type::ConferenceChatMessage:
				eventLog = selectConferenceChatMessageEvent(eventId, type, creationTime, chatRoomId);
				break;

			case EventLog::Type::ConferenceParticipantAdded:
			case EventLog::Type::ConferenceParticipantRemoved:
			case EventLog::Type::ConferenceParticipantSetAdmin:
			case EventLog::Type::ConferenceParticipantUnsetAdmin:
				eventLog = selectConferenceParticipantEvent(eventId, type, creationTime, chatRoomId);
				break;

			case EventLog::Type::ConferenceParticipantDeviceAdded:
			case EventLog::Type::ConferenceParticipantDeviceRemoved:
				eventLog = selectConferenceParticipantDeviceEvent(eventId, type, creationTime, chatRoomId);
				break;

			case EventLog::Type::ConferenceSubjectChanged:
				eventLog = selectConferenceSubjectEvent(eventId, type, creationTime, chatRoomId);
				break;
		}

		if (eventLog)
			cache(eventLog, eventId);

		return eventLog;
	}

	shared_ptr<EventLog> MainDbPrivate::selectConferenceEvent (
		long long,
		EventLog::Type type,
		time_t creationTime,
		const ChatRoomId &chatRoomId
	) const {
		return make_shared<ConferenceEvent>(
			type,
			creationTime,
			chatRoomId
		);
	}

	shared_ptr<EventLog> MainDbPrivate::selectConferenceCallEvent (
		long long eventId,
		EventLog::Type type,
		time_t creationTime,
		const ChatRoomId &chatRoomId
	) const {
		// TODO.
		return nullptr;
	}

	shared_ptr<EventLog> MainDbPrivate::selectConferenceChatMessageEvent (
		long long eventId,
		EventLog::Type type,
		time_t creationTime,
		const ChatRoomId &chatRoomId
	) const {
		L_Q();

		shared_ptr<Core> core = q->getCore();
		shared_ptr<ChatRoom> chatRoom = core->findChatRoom(chatRoomId);
		if (!chatRoom)
			return nullptr;

		bool hasFileTransferContent = false;

		// 1 - Fetch chat message.
		shared_ptr<ChatMessage> chatMessage = getChatMessageFromCache(eventId);
		if (chatMessage)
			goto end;
		{
			string fromSipAddress;
			string toSipAddress;

			tm messageTime;

			string imdnMessageId;

			int state;
			int direction;
			int isSecured;

			soci::session *session = dbSession.getBackendSession<soci::session>();
			*session << "SELECT from_sip_address.value, to_sip_address.value, time, imdn_message_id, state, direction, is_secured"
				"  FROM event, conference_chat_message_event, sip_address AS from_sip_address,"
				"  sip_address AS to_sip_address"
				"  WHERE event_id = :eventId"
				"  AND event_id = event.id"
				"  AND from_sip_address_id = from_sip_address.id"
				"  AND to_sip_address_id = to_sip_address.id", soci::into(fromSipAddress), soci::into(toSipAddress),
				soci::into(messageTime), soci::into(imdnMessageId), soci::into(state), soci::into(direction),
				soci::into(isSecured), soci::use(eventId);

			chatMessage = shared_ptr<ChatMessage>(new ChatMessage(
				chatRoom,
				static_cast<ChatMessage::Direction>(direction)
			));
			chatMessage->setIsSecured(static_cast<bool>(isSecured));

			ChatMessagePrivate *dChatMessage = chatMessage->getPrivate();
			dChatMessage->setState(static_cast<ChatMessage::State>(state), true);

			dChatMessage->forceFromAddress(IdentityAddress(fromSipAddress));
			dChatMessage->forceToAddress(IdentityAddress(toSipAddress));

			dChatMessage->setTime(Utils::getTmAsTimeT(messageTime));
		}

		// 2 - Fetch contents.
		{
			soci::session *session = dbSession.getBackendSession<soci::session>();
			static const string query = "SELECT chat_message_content.id, content_type.id, content_type.value, body"
				"  FROM chat_message_content, content_type"
				"  WHERE event_id = :eventId AND content_type_id = content_type.id";
			soci::rowset<soci::row> rows = (session->prepare << query, soci::use(eventId));
			for (const auto &row : rows) {
				ContentType contentType(row.get<string>(2));
				const long long &contentId = resolveId(row, 0);
				Content *content;

				if (contentType == ContentType::FileTransfer) {
					hasFileTransferContent = true;
					content = new FileTransferContent();
				}
				else if (contentType.isFile()) {
					// 2.1 - Fetch contents' file informations.
					string name;
					int size;
					string path;

					*session << "SELECT name, size, path FROM chat_message_file_content"
						"  WHERE chat_message_content_id = :contentId",
						soci::into(name), soci::into(size), soci::into(path), soci::use(contentId);

					FileContent *fileContent = new FileContent();
					fileContent->setFileName(name);
					fileContent->setFileSize(static_cast<size_t>(size));
					fileContent->setFilePath(path);

					content = fileContent;
				} else
					content = new Content();

				// 2.2 - Fetch contents' app data.
				static const string query = "SELECT name, data FROM chat_message_content_app_data"
					"  WHERE chat_message_content_id = :contentId";
				soci::rowset<soci::row> rows = (session->prepare << query, soci::use(contentId));
				for (const auto &row : rows)
					content->setAppData(row.get<string>(0), row.get<string>(1));

				content->setContentType(contentType);
				content->setBody(row.get<string>(3));
				chatMessage->addContent(*content);
			}
		}

		// 3 - Load external body url from body into FileTransferContent if needed
		if (hasFileTransferContent) {
			ChatMessagePrivate *dChatMessage = chatMessage->getPrivate();
			dChatMessage->loadFileTransferUrlFromBodyToContent();
		}

		cache(chatMessage, eventId);

	end:
		return make_shared<ConferenceChatMessageEvent>(
			creationTime,
			chatMessage
		);
	}

	shared_ptr<EventLog> MainDbPrivate::selectConferenceParticipantEvent (
		long long eventId,
		EventLog::Type type,
		time_t creationTime,
		const ChatRoomId &chatRoomId
	) const {
		unsigned int notifyId;
		string participantAddress;

		soci::session *session = dbSession.getBackendSession<soci::session>();
		*session << "SELECT notify_id, participant_address.value"
			"  FROM conference_notified_event, conference_participant_event, sip_address as participant_address"
			"  WHERE conference_participant_event.event_id = :eventId"
			"    AND conference_notified_event.event_id = conference_participant_event.event_id"
			"    AND participant_address.id = participant_sip_address_id",
			soci::into(notifyId), soci::into(participantAddress), soci::use(eventId);

		return make_shared<ConferenceParticipantEvent>(
			type,
			creationTime,
			chatRoomId,
			notifyId,
			IdentityAddress(participantAddress)
		);
	}

	shared_ptr<EventLog> MainDbPrivate::selectConferenceParticipantDeviceEvent (
		long long eventId,
		EventLog::Type type,
		time_t creationTime,
		const ChatRoomId &chatRoomId
	) const {
		unsigned int notifyId;
		string participantAddress;
		string deviceAddress;

		soci::session *session = dbSession.getBackendSession<soci::session>();
		*session << "SELECT notify_id, participant_address.value, device_address.value"
			"  FROM conference_notified_event, conference_participant_event, conference_participant_device_event,"
			"    sip_address AS participant_address, sip_address AS device_address"
			"  WHERE conference_participant_device_event.event_id = :eventId"
			"    AND conference_participant_event.event_id = conference_participant_device_event.event_id"
			"    AND conference_notified_event.event_id = conference_participant_event.event_id"
			"    AND participant_address.id = participant_sip_address_id"
			"    AND device_address.id = device_sip_address_id",
			soci::into(notifyId), soci::into(participantAddress), soci::into(deviceAddress), soci::use(eventId);

		return make_shared<ConferenceParticipantDeviceEvent>(
			type,
			creationTime,
			chatRoomId,
			notifyId,
			IdentityAddress(participantAddress),
			IdentityAddress(deviceAddress)
		);
	}

	shared_ptr<EventLog> MainDbPrivate::selectConferenceSubjectEvent (
		long long eventId,
		EventLog::Type type,
		time_t creationTime,
		const ChatRoomId &chatRoomId
	) const {
		unsigned int notifyId;
		string subject;

		soci::session *session = dbSession.getBackendSession<soci::session>();
		*session << "SELECT notify_id, subject"
			"  FROM conference_notified_event, conference_subject_event"
			"  WHERE conference_subject_event.event_id = :eventId"
			"    AND conference_notified_event.event_id = conference_subject_event.event_id",
			soci::into(notifyId), soci::into(subject), soci::use(eventId);

		return make_shared<ConferenceSubjectEvent>(
			creationTime,
			chatRoomId,
			notifyId,
			subject
		);
	}

// -----------------------------------------------------------------------------

	long long MainDbPrivate::insertEvent (const shared_ptr<EventLog> &eventLog) {
		L_Q();
		soci::session *session = dbSession.getBackendSession<soci::session>();

		const int &type = static_cast<int>(eventLog->getType());
		const tm &creationTime = Utils::getTimeTAsTm(eventLog->getCreationTime());
		*session << "INSERT INTO event (type, creation_time) VALUES (:type, :creationTime)",
			soci::use(type),
			soci::use(creationTime);

		return q->getLastInsertId();
	}

	long long MainDbPrivate::insertConferenceEvent (const shared_ptr<EventLog> &eventLog, long long *chatRoomId) {
		shared_ptr<ConferenceEvent> conferenceEvent = static_pointer_cast<ConferenceEvent>(eventLog);

		long long eventId = -1;
		const long long &curChatRoomId = selectChatRoomId(conferenceEvent->getChatRoomId());
		if (curChatRoomId < 0) {
			// A conference event can be inserted in database only if chat room exists.
			// Otherwise it's an error.
			const ChatRoomId &chatRoomId = conferenceEvent->getChatRoomId();
			lError() << "Unable to find chat room storage id of (peer=" +
				chatRoomId.getPeerAddress().asString() +
				", local=" + chatRoomId.getLocalAddress().asString() + "`).";
		} else {
			eventId = insertEvent(eventLog);

			soci::session *session = dbSession.getBackendSession<soci::session>();
			*session << "INSERT INTO conference_event (event_id, chat_room_id)"
				"  VALUES (:eventId, :chatRoomId)", soci::use(eventId), soci::use(curChatRoomId);

			const tm &lastUpdateTime = Utils::getTimeTAsTm(eventLog->getCreationTime());
			*session << "UPDATE chat_room SET last_update_time = :lastUpdateTime"
				"  WHERE id = :chatRoomId", soci::use(lastUpdateTime),
				soci::use(curChatRoomId);

			if (eventLog->getType() == EventLog::Type::ConferenceTerminated)
				*session << "UPDATE chat_room SET flags = 1 WHERE id = :chatRoomId", soci::use(curChatRoomId);
		}

		if (chatRoomId)
			*chatRoomId = curChatRoomId;

		return eventId;
	}

	long long MainDbPrivate::insertConferenceCallEvent (const shared_ptr<EventLog> &eventLog) {
		// TODO.
		return 0;
	}

	long long MainDbPrivate::insertConferenceChatMessageEvent (const shared_ptr<EventLog> &eventLog) {
		shared_ptr<ChatMessage> chatMessage = static_pointer_cast<ConferenceChatMessageEvent>(eventLog)->getChatMessage();
		shared_ptr<ChatRoom> chatRoom = chatMessage->getChatRoom();
		if (!chatRoom) {
			lError() << "Unable to get a valid chat room. It was removed from database.";
			return -1;
		}

		const long long &eventId = insertConferenceEvent(eventLog);
		if (eventId < 0)
			return -1;

		soci::session *session = dbSession.getBackendSession<soci::session>();

		const long long &fromSipAddressId = insertSipAddress(chatMessage->getFromAddress().asString());
		const long long &toSipAddressId = insertSipAddress(chatMessage->getToAddress().asString());
		const tm &messageTime = Utils::getTimeTAsTm(chatMessage->getTime());
		const int &state = static_cast<int>(chatMessage->getState());
		const int &direction = static_cast<int>(chatMessage->getDirection());
		const string &imdnMessageId = chatMessage->getImdnMessageId();
		const int &isSecured = chatMessage->isSecured() ? 1 : 0;

		*session << "INSERT INTO conference_chat_message_event ("
			"  event_id, from_sip_address_id, to_sip_address_id,"
			"  time, state, direction, imdn_message_id, is_secured"
			") VALUES ("
			"  :eventId, :localSipaddressId, :remoteSipaddressId,"
			"  :time, :state, :direction, :imdnMessageId, :isSecured"
			")", soci::use(eventId), soci::use(fromSipAddressId), soci::use(toSipAddressId),
			soci::use(messageTime), soci::use(state), soci::use(direction),
			soci::use(imdnMessageId), soci::use(isSecured);

		for (const Content *content : chatMessage->getContents())
			insertContent(eventId, *content);

		return eventId;
	}

	void MainDbPrivate::updateConferenceChatMessageEvent (const shared_ptr<EventLog> &eventLog) {
		shared_ptr<ChatMessage> chatMessage = static_pointer_cast<ConferenceChatMessageEvent>(eventLog)->getChatMessage();
		shared_ptr<ChatRoom> chatRoom = chatMessage->getChatRoom();
		if (!chatRoom) {
			lError() << "Unable to get a valid chat room. It was removed from database.";
			return;
		}

		const EventLogPrivate *dEventLog = eventLog->getPrivate();
		MainDbKeyPrivate *dEventKey = static_cast<MainDbKey &>(dEventLog->dbKey).getPrivate();
		const long long &eventId = dEventKey->storageId;

		soci::session *session = dbSession.getBackendSession<soci::session>();
		const int &state = static_cast<int>(chatMessage->getState());
		*session << "UPDATE conference_chat_message_event SET state = :state WHERE event_id = :eventId",
			soci::use(state), soci::use(eventId);

		//TODO: improve
		removeContentsForChatMessageEvent(eventId);
		for (const Content *content : chatMessage->getContents())
			insertContent(eventId, *content);
	}

	long long MainDbPrivate::insertConferenceNotifiedEvent (const shared_ptr<EventLog> &eventLog, long long *chatRoomId) {
		long long curChatRoomId;
		const long long &eventId = insertConferenceEvent(eventLog, &curChatRoomId);
		if (eventId < 0)
			return -1;

		const unsigned int &lastNotifyId = static_pointer_cast<ConferenceNotifiedEvent>(eventLog)->getNotifyId();

		soci::session *session = dbSession.getBackendSession<soci::session>();
		*session << "INSERT INTO conference_notified_event (event_id, notify_id)"
			"  VALUES (:eventId, :notifyId)", soci::use(eventId), soci::use(lastNotifyId);
		*session << "UPDATE chat_room SET last_notify_id = :lastNotifyId WHERE id = :chatRoomId",
			soci::use(lastNotifyId), soci::use(curChatRoomId);

		if (chatRoomId)
			*chatRoomId = curChatRoomId;

		return eventId;
	}

	long long MainDbPrivate::insertConferenceParticipantEvent (const shared_ptr<EventLog> &eventLog) {
		long long chatRoomId;
		const long long &eventId = insertConferenceNotifiedEvent(eventLog, &chatRoomId);
		if (eventId < 0)
			return -1;

		shared_ptr<ConferenceParticipantEvent> participantEvent =
			static_pointer_cast<ConferenceParticipantEvent>(eventLog);

		const long long &participantAddressId = insertSipAddress(
			participantEvent->getParticipantAddress().asString()