/*
This file is part of Telegram Desktop,
the official desktop version of Telegram messaging app, see https://telegram.org

Telegram Desktop 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 3 of the License, or
(at your option) any later version.

It 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.

In addition, as a special exception, the copyright holders give permission
to link the code of portions of this program with the OpenSSL library.

Full license: https://github.com/telegramdesktop/tdesktop/blob/master/LICENSE
Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
*/
#include "stdafx.h"
#include "mtproto/mtp_instance.h"

#include "mtproto/dc_options.h"
#include "localstorage.h"
#include "auth_session.h"
#include "messenger.h"
#include "mtproto/connection.h"

namespace MTP {

class Instance::Private {
public:
	Private(Instance *instance, DcOptions *options);

	void start(Config &&config);

	void suggestMainDcId(DcId mainDcId);
	void setMainDcId(DcId mainDcId);
	DcId mainDcId() const;

	void setKeyForWrite(DcId dcId, const AuthKeyPtr &key);
	AuthKeysMap getKeysForWrite() const;

	DcOptions *dcOptions();

	void configLoadRequest();

	void restart();
	void restart(ShiftedDcId shiftedDcId);
	int32 dcstate(ShiftedDcId shiftedDcId = 0);
	QString dctransport(ShiftedDcId shiftedDcId = 0);
	void ping();
	void cancel(mtpRequestId requestId);
	int32 state(mtpRequestId requestId); // < 0 means waiting for such count of ms
	void killSession(ShiftedDcId shiftedDcId);
	void stopSession(ShiftedDcId shiftedDcId);
	void logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail);

	internal::DcenterPtr getDcById(DcId dcId);
	void unpaused();

	void queueQuittingConnection(std::unique_ptr<internal::Connection> connection);
	void connectionFinished(internal::Connection *connection);

	void registerRequest(mtpRequestId requestId, int32 dcWithShift);
	void unregisterRequest(mtpRequestId requestId);
	mtpRequestId storeRequest(mtpRequest &request, const RPCResponseHandler &parser);
	mtpRequest getRequest(mtpRequestId requestId);
	void clearCallbacks(mtpRequestId requestId, int32 errorCode = RPCError::NoError); // 0 - do not toggle onError callback
	void clearCallbacksDelayed(const RPCCallbackClears &requestIds);
	void performDelayedClear();
	void execCallback(mtpRequestId requestId, const mtpPrime *from, const mtpPrime *end);
	bool hasCallbacks(mtpRequestId requestId);
	void globalCallback(const mtpPrime *from, const mtpPrime *end);

	void onStateChange(ShiftedDcId dcWithShift, int32 state);
	void onSessionReset(ShiftedDcId dcWithShift);

	// return true if need to clean request data
	bool rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err);
	inline bool rpcErrorOccured(mtpRequestId requestId, const RPCResponseHandler &handler, const RPCError &err) {
		return rpcErrorOccured(requestId, handler.onFail, err);
	}

	void setUpdatesHandler(RPCDoneHandlerPtr onDone);
	void setGlobalFailHandler(RPCFailHandlerPtr onFail);
	void setStateChangedHandler(base::lambda<void(ShiftedDcId shiftedDcId, int32 state)> &&handler);
	void setSessionResetHandler(base::lambda<void(ShiftedDcId shiftedDcId)> &&handler);
	void clearGlobalHandlers();

	internal::Session *getSession(ShiftedDcId shiftedDcId);

	~Private();

private:
	bool hasAuthorization();
	void importDone(const MTPauth_Authorization &result, mtpRequestId requestId);
	bool importFail(const RPCError &error, mtpRequestId requestId);
	void exportDone(const MTPauth_ExportedAuthorization &result, mtpRequestId requestId);
	bool exportFail(const RPCError &error, mtpRequestId requestId);
	bool onErrorDefault(mtpRequestId requestId, const RPCError &error);

	bool logoutGuestDone(mtpRequestId requestId);

	void configLoadDone(const MTPConfig &result);
	bool configLoadFail(const RPCError &error);

	void checkDelayedRequests();

	Instance *_instance = nullptr;

	DcOptions *_dcOptions = nullptr;

	DcId _mainDcId = Config::kDefaultMainDc;
	bool _mainDcIdForced = false;
	internal::DcenterMap _dcenters;

	internal::Session *_mainSession = nullptr;
	std::map<ShiftedDcId, std::unique_ptr<internal::Session>> _sessions;

	base::set_of_unique_ptr<internal::Connection> _quittingConnections;

	std::unique_ptr<internal::ConfigLoader> _configLoader;

	std::map<DcId, AuthKeyPtr> _keysForWrite;
	mutable QReadWriteLock _keysForWriteLock;

	std::map<ShiftedDcId, mtpRequestId> _logoutGuestRequestIds;

	// holds dcWithShift for request to this dc or -dc for request to main dc
	std::map<mtpRequestId, ShiftedDcId> _requestsByDc;
	QMutex _requestByDcLock;

	// holds target dcWithShift for auth export request
	std::map<mtpRequestId, ShiftedDcId> _authExportRequests;

	std::map<mtpRequestId, RPCResponseHandler> _parserMap;
	QMutex _parserMapLock;

	std::map<mtpRequestId, mtpRequest> _requestMap;
	QReadWriteLock _requestMapLock;

	std::deque<std::pair<mtpRequestId, TimeMs>> _delayedRequests;

	std::map<mtpRequestId, int> _requestsDelays;

	std::set<mtpRequestId> _badGuestDcRequests;

	std::map<DcId, std::vector<mtpRequestId>> _authWaiters;

	QMutex _toClearLock;
	RPCCallbackClears _toClear;

	RPCResponseHandler _globalHandler;
	base::lambda<void(ShiftedDcId shiftedDcId, int32 state)> _stateChangedHandler;
	base::lambda<void(ShiftedDcId shiftedDcId)> _sessionResetHandler;

	SingleTimer _checkDelayedTimer;

};

Instance::Private::Private(Instance *instance, DcOptions *options) : _instance(instance)
, _dcOptions(options) {
}

void Instance::Private::start(Config &&config) {
	unixtimeInit();

	for (auto &keyData : config.keys) {
		auto dcId = keyData.first;
		auto key = std::make_shared<AuthKey>();
		key->setDC(dcId);
		key->setKey(keyData.second);

		_keysForWrite[dcId] = key;

		auto dc = std::make_shared<internal::Dcenter>(_instance, dcId, std::move(key));
		_dcenters.emplace(dcId, std::move(dc));
	}

	if (config.mainDcId != Config::kNotSetMainDc) {
		_mainDcId = config.mainDcId;
		_mainDcIdForced = true;
	}
	if (_mainDcId != Config::kNoneMainDc) {
		auto main = std::make_unique<internal::Session>(_instance, _mainDcId);
		_mainSession = main.get();
		auto newMainDcId = main->getDcWithShift();
		_sessions.emplace(newMainDcId, std::move(main));
	}

	_checkDelayedTimer.setTimeoutHandler([this] {
		checkDelayedRequests();
	});

	configLoadRequest();
}

void Instance::Private::suggestMainDcId(DcId mainDcId) {
	if (_mainDcIdForced) return;
	setMainDcId(mainDcId);
}

void Instance::Private::setMainDcId(DcId mainDcId) {
	if (!_mainSession) {
		LOG(("MTP Error: attempting to change mainDcId in an MTP instance without main session."));
		return;
	}

	_mainDcIdForced = true;
	auto oldMainDcId = _mainSession->getDcWithShift();
	_mainDcId = mainDcId;
	if (oldMainDcId != _mainDcId) {
		killSession(oldMainDcId);
	}
	Local::writeMtpData();
}

DcId Instance::Private::mainDcId() const {
	t_assert(_mainDcId != Config::kNoneMainDc);
	return _mainDcId;
}

void Instance::Private::configLoadRequest() {
	if (_configLoader) {
		return;
	}
	_configLoader = std::make_unique<internal::ConfigLoader>(_instance, rpcDone([this](const MTPConfig &result) {
		configLoadDone(result);
	}), rpcFail([this](const RPCError &error) {
		return configLoadFail(error);
	}));
	_configLoader->load();
}

void Instance::Private::restart() {
	for (auto &session : _sessions) {
		session.second->restart();
	}
}

void Instance::Private::restart(ShiftedDcId shiftedDcId) {
	auto dcId = bareDcId(shiftedDcId);
	for (auto &session : _sessions) {
		if (bareDcId(session.second->getDcWithShift()) == dcId) {
			session.second->restart();
		}
	}
}

int32 Instance::Private::dcstate(ShiftedDcId shiftedDcId) {
	if (!shiftedDcId) {
		t_assert(_mainSession != nullptr);
		return _mainSession->getState();
	}

	if (!bareDcId(shiftedDcId)) {
		t_assert(_mainSession != nullptr);
		shiftedDcId += bareDcId(_mainSession->getDcWithShift());
	}

	auto it = _sessions.find(shiftedDcId);
	if (it != _sessions.cend()) return it->second->getState();

	return DisconnectedState;
}

QString Instance::Private::dctransport(ShiftedDcId shiftedDcId) {
	if (!shiftedDcId) {
		t_assert(_mainSession != nullptr);
		return _mainSession->transport();
	}
	if (!bareDcId(shiftedDcId)) {
		t_assert(_mainSession != nullptr);
		shiftedDcId += bareDcId(_mainSession->getDcWithShift());
	}

	auto it = _sessions.find(shiftedDcId);
	if (it != _sessions.cend()) {
		return it->second->transport();
	}

	return QString();
}

void Instance::Private::ping() {
	if (auto session = getSession(0)) {
		session->ping();
	}
}

void Instance::Private::cancel(mtpRequestId requestId) {
	if (!requestId) return;

	mtpMsgId msgId = 0;
	_requestsDelays.erase(requestId);
	{
		QWriteLocker locker(&_requestMapLock);
		auto it = _requestMap.find(requestId);
		if (it != _requestMap.end()) {
			msgId = *(mtpMsgId*)(it->second->constData() + 4);
			_requestMap.erase(it);
		}
	}
	{
		QMutexLocker locker(&_requestByDcLock);
		auto it = _requestsByDc.find(requestId);
		if (it != _requestsByDc.end()) {
			if (auto session = getSession(qAbs(it->second))) {
				session->cancel(requestId, msgId);
			}
			_requestsByDc.erase(it);
		}
	}
	clearCallbacks(requestId);
}

int32 Instance::Private::state(mtpRequestId requestId) { // < 0 means waiting for such count of ms
	if (requestId > 0) {
		QMutexLocker locker(&_requestByDcLock);
		auto i = _requestsByDc.find(requestId);
		if (i != _requestsByDc.end()) {
			if (auto session = getSession(qAbs(i->second))) {
				return session->requestState(requestId);
			}
			return MTP::RequestConnecting;
		}
		return MTP::RequestSent;
	}
	if (auto session = getSession(-requestId)) {
		return session->requestState(0);
	}
	return MTP::RequestConnecting;
}

void Instance::Private::killSession(ShiftedDcId shiftedDcId) {
	auto it = _sessions.find(shiftedDcId);
	if (it != _sessions.cend()) {
		bool wasMain = (it->second.get() == _mainSession);

		it->second->kill();
		it->second.release()->deleteLater();
		_sessions.erase(it);

		if (wasMain) {
			auto main = std::make_unique<internal::Session>(_instance, _mainDcId);
			_mainSession = main.get();
			auto newMainDcId = main->getDcWithShift();
			it = _sessions.find(newMainDcId);
			if (it != _sessions.cend()) {
				it->second->kill();
				it->second.release()->deleteLater();
				_sessions.erase(it);
			}
			_sessions.insert(std::make_pair(newMainDcId, std::move(main)));
		}
	}
}

void Instance::Private::stopSession(ShiftedDcId shiftedDcId) {
	auto it = _sessions.find(shiftedDcId);
	if (it != _sessions.end()) {
		if (it->second.get() != _mainSession) { // don't stop main session
			it->second->stop();
		}
	}
}

void Instance::Private::logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail) {
	_instance->send(MTPauth_LogOut(), onDone, onFail);

	auto dcIds = std::vector<DcId>();
	{
		QReadLocker lock(&_keysForWriteLock);
		dcIds.reserve(_keysForWrite.size());
		for (auto &key : _keysForWrite) {
			dcIds.push_back(key.first);
		}
	}
	for (auto dcId : dcIds) {
		if (dcId != mainDcId()) {
			auto shiftedDcId = MTP::lgtDcId(dcId);
			auto requestId = _instance->send(MTPauth_LogOut(), rpcDone([this](mtpRequestId requestId) {
				logoutGuestDone(requestId);
			}), rpcFail([this](mtpRequestId requestId) {
				return logoutGuestDone(requestId);
			}), shiftedDcId);
			_logoutGuestRequestIds.insert(std::make_pair(shiftedDcId, requestId));
		}
	}
}

bool Instance::Private::logoutGuestDone(mtpRequestId requestId) {
	for (auto i = _logoutGuestRequestIds.begin(), e = _logoutGuestRequestIds.end(); i != e; ++i) {
		if (i->second == requestId) {
			killSession(i->first);
			_logoutGuestRequestIds.erase(i);
			return true;
		}
	}
	return false;
}

internal::DcenterPtr Instance::Private::getDcById(DcId dcId) {
	auto it = _dcenters.find(dcId);
	if (it == _dcenters.cend()) {
		auto result = std::make_shared<internal::Dcenter>(_instance, dcId, AuthKeyPtr());
		auto insert = std::make_pair(dcId, std::move(result));
		it = _dcenters.insert(std::move(insert)).first;
	}
	return it->second;
}

void Instance::Private::setKeyForWrite(DcId dcId, const AuthKeyPtr &key) {
	QWriteLocker lock(&_keysForWriteLock);
	if (key) {
		_keysForWrite[dcId] = key;
	} else {
		_keysForWrite.erase(dcId);
	}
}

AuthKeysMap Instance::Private::getKeysForWrite() const {
	auto result = AuthKeysMap();
	QReadLocker lock(&_keysForWriteLock);
	for (auto &key : _keysForWrite) {
		result.push_back(key.second);
	}
	return result;
}

DcOptions *Instance::Private::dcOptions() {
	return _dcOptions;
}

void Instance::Private::unpaused() {
	for (auto &session : _sessions) {
		session.second->unpaused();
	}
}

void Instance::Private::queueQuittingConnection(std::unique_ptr<internal::Connection> connection) {
	_quittingConnections.insert(std::move(connection));
}

void Instance::Private::connectionFinished(internal::Connection *connection) {
	auto it = _quittingConnections.find(connection);
	if (it != _quittingConnections.end()) {
		_quittingConnections.erase(it);
	}
}

void Instance::Private::configLoadDone(const MTPConfig &result) {
	_configLoader.reset();

	if (result.type() != mtpc_config) {
		LOG(("MTP Error: wrong config constructor: %1").arg(result.type()));
		return;
	}
	auto &data = result.c_config();

	DEBUG_LOG(("MTP Info: got config, chat_size_max: %1, date: %2, test_mode: %3, this_dc: %4, dc_options.length: %5").arg(data.vchat_size_max.v).arg(data.vdate.v).arg(mtpIsTrue(data.vtest_mode)).arg(data.vthis_dc.v).arg(data.vdc_options.c_vector().v.size()));

	if (data.vdc_options.c_vector().v.empty()) {
		LOG(("MTP Error: config with empty dc_options received!"));
	} else {
		_dcOptions->setFromList(data.vdc_options);
	}

	Global::SetChatSizeMax(data.vchat_size_max.v);
	Global::SetMegagroupSizeMax(data.vmegagroup_size_max.v);
	Global::SetForwardedCountMax(data.vforwarded_count_max.v);
	Global::SetOnlineUpdatePeriod(data.vonline_update_period_ms.v);
	Global::SetOfflineBlurTimeout(data.voffline_blur_timeout_ms.v);
	Global::SetOfflineIdleTimeout(data.voffline_idle_timeout_ms.v);
	Global::SetOnlineCloudTimeout(data.vonline_cloud_timeout_ms.v);
	Global::SetNotifyCloudDelay(data.vnotify_cloud_delay_ms.v);
	Global::SetNotifyDefaultDelay(data.vnotify_default_delay_ms.v);
	Global::SetChatBigSize(data.vchat_big_size.v); // ?
	Global::SetPushChatPeriod(data.vpush_chat_period_ms.v); // ?
	Global::SetPushChatLimit(data.vpush_chat_limit.v); // ?
	Global::SetSavedGifsLimit(data.vsaved_gifs_limit.v);
	Global::SetEditTimeLimit(data.vedit_time_limit.v); // ?
	Global::SetStickersRecentLimit(data.vstickers_recent_limit.v);
	Global::SetPinnedDialogsCountMax(data.vpinned_dialogs_count_max.v);

	Local::writeSettings();

	emit _instance->configLoaded();
}

bool Instance::Private::configLoadFail(const RPCError &error) {
	if (isDefaultHandledError(error)) return false;

	//	loadingConfig = false;
	LOG(("MTP Error: failed to get config!"));
	return false;
}

void Instance::Private::checkDelayedRequests() {
	auto now = getms(true);
	while (!_delayedRequests.empty() && now >= _delayedRequests.front().second) {
		auto requestId = _delayedRequests.front().first;
		_delayedRequests.pop_front();

		auto dcWithShift = ShiftedDcId(0);
		{
			QMutexLocker locker(&_requestByDcLock);
			auto it = _requestsByDc.find(requestId);
			if (it != _requestsByDc.cend()) {
				dcWithShift = it->second;
			} else {
				LOG(("MTP Error: could not find request dc for delayed resend, requestId %1").arg(requestId));
				continue;
			}
		}

		auto request = mtpRequest();
		{
			QReadLocker locker(&_requestMapLock);
			auto it = _requestMap.find(requestId);
			if (it == _requestMap.cend()) {
				DEBUG_LOG(("MTP Error: could not find request %1").arg(requestId));
				continue;
			}
			request = it->second;
		}
		if (auto session = getSession(qAbs(dcWithShift))) {
			session->sendPrepared(request);
		}
	}

	if (!_delayedRequests.empty()) {
		_checkDelayedTimer.start(_delayedRequests.front().second - now);
	}
}

void Instance::Private::registerRequest(mtpRequestId requestId, int32 dcWithShift) {
	{
		QMutexLocker locker(&_requestByDcLock);
		_requestsByDc.emplace(requestId, dcWithShift);
	}
	performDelayedClear(); // need to do it somewhere...
}

void Instance::Private::unregisterRequest(mtpRequestId requestId) {
	_requestsDelays.erase(requestId);

	{
		QWriteLocker locker(&_requestMapLock);
		_requestMap.erase(requestId);
	}

	QMutexLocker locker(&_requestByDcLock);
	_requestsByDc.erase(requestId);
}

mtpRequestId Instance::Private::storeRequest(mtpRequest &request, const RPCResponseHandler &parser) {
	mtpRequestId res = reqid();
	request->requestId = res;
	if (parser.onDone || parser.onFail) {
		QMutexLocker locker(&_parserMapLock);
		_parserMap.emplace(res, parser);
	}
	{
		QWriteLocker locker(&_requestMapLock);
		_requestMap.emplace(res, request);
	}
	return res;
}

mtpRequest Instance::Private::getRequest(mtpRequestId requestId) {
	auto result = mtpRequest();
	{
		QReadLocker locker(&_requestMapLock);
		auto it = _requestMap.find(requestId);
		if (it != _requestMap.cend()) {
			result = it->second;
		}
	}
	return result;
}


void Instance::Private::clearCallbacks(mtpRequestId requestId, int32 errorCode) {
	RPCResponseHandler h;
	bool found = false;
	{
		QMutexLocker locker(&_parserMapLock);
		auto it = _parserMap.find(requestId);
		if (it != _parserMap.end()) {
			h = it->second;
			found = true;

			_parserMap.erase(it);
		}
	}
	if (errorCode && found) {
		rpcErrorOccured(requestId, h, internal::rpcClientError("CLEAR_CALLBACK", QString("did not handle request %1, error code %2").arg(requestId).arg(errorCode)));
	}
}

void Instance::Private::clearCallbacksDelayed(const RPCCallbackClears &requestIds) {
	uint32 idsCount = requestIds.size();
	if (!idsCount) return;

	if (cDebug()) {
		QString idsStr = QString("%1").arg(requestIds[0].requestId);
		for (uint32 i = 1; i < idsCount; ++i) {
			idsStr += QString(", %1").arg(requestIds[i].requestId);
		}
		DEBUG_LOG(("RPC Info: clear callbacks delayed, msgIds: %1").arg(idsStr));
	}

	QMutexLocker lock(&_toClearLock);
	uint32 toClearNow = _toClear.size();
	if (toClearNow) {
		_toClear.resize(toClearNow + idsCount);
		memcpy(_toClear.data() + toClearNow, requestIds.constData(), idsCount * sizeof(RPCCallbackClear));
	} else {
		_toClear = requestIds;
	}
}

void Instance::Private::performDelayedClear() {
	QMutexLocker lock(&_toClearLock);
	if (!_toClear.isEmpty()) {
		for (auto &clearRequest : _toClear) {
			if (cDebug()) {
				QMutexLocker locker(&_parserMapLock);
				if (_parserMap.find(clearRequest.requestId) != _parserMap.end()) {
					DEBUG_LOG(("RPC Info: clearing delayed callback %1, error code %2").arg(clearRequest.requestId).arg(clearRequest.errorCode));
				}
			}
			clearCallbacks(clearRequest.requestId, clearRequest.errorCode);
			unregisterRequest(clearRequest.requestId);
		}
		_toClear.clear();
	}
}

void Instance::Private::execCallback(mtpRequestId requestId, const mtpPrime *from, const mtpPrime *end) {
	RPCResponseHandler h;
	{
		QMutexLocker locker(&_parserMapLock);
		auto it = _parserMap.find(requestId);
		if (it != _parserMap.cend()) {
			h = it->second;
			_parserMap.erase(it);

			DEBUG_LOG(("RPC Info: found parser for request %1, trying to parse response...").arg(requestId));
		}
	}
	if (h.onDone || h.onFail) {
		try {
			if (from >= end) throw mtpErrorInsufficient();

			if (*from == mtpc_rpc_error) {
				RPCError err(MTPRpcError(from, end));
				DEBUG_LOG(("RPC Info: error received, code %1, type %2, description: %3").arg(err.code()).arg(err.type()).arg(err.description()));
				if (!rpcErrorOccured(requestId, h, err)) {
					QMutexLocker locker(&_parserMapLock);
					_parserMap.emplace(requestId, h);
					return;
				}
			} else {
				if (h.onDone) {
					(*h.onDone)(requestId, from, end);
				}
			}
		} catch (Exception &e) {
			if (!rpcErrorOccured(requestId, h, internal::rpcClientError("RESPONSE_PARSE_FAILED", QString("exception text: ") + e.what()))) {
				QMutexLocker locker(&_parserMapLock);
				_parserMap.emplace(requestId, h);
				return;
			}
		}
	} else {
		DEBUG_LOG(("RPC Info: parser not found for %1").arg(requestId));
	}
	unregisterRequest(requestId);
}

bool Instance::Private::hasCallbacks(mtpRequestId requestId) {
	QMutexLocker locker(&_parserMapLock);
	auto it = _parserMap.find(requestId);
	return (it != _parserMap.cend());
}

void Instance::Private::globalCallback(const mtpPrime *from, const mtpPrime *end) {
	if (_globalHandler.onDone) {
		(*_globalHandler.onDone)(0, from, end); // some updates were received
	}
}

void Instance::Private::onStateChange(int32 dcWithShift, int32 state) {
	if (_stateChangedHandler) {
		_stateChangedHandler(dcWithShift, state);
	}
}

void Instance::Private::onSessionReset(int32 dcWithShift) {
	if (_sessionResetHandler) {
		_sessionResetHandler(dcWithShift);
	}
}

bool Instance::Private::rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err) { // return true if need to clean request data
	if (isDefaultHandledError(err)) {
		if (onFail && (*onFail)(requestId, err)) return true;
	}

	if (onErrorDefault(requestId, err)) {
		return false;
	}
	LOG(("RPC Error: request %1 got fail with code %2, error %3%4").arg(requestId).arg(err.code()).arg(err.type()).arg(err.description().isEmpty() ? QString() : QString(": %1").arg(err.description())));
	onFail && (*onFail)(requestId, err);
	return true;
}

bool Instance::Private::hasAuthorization() {
	return (AuthSession::Current() != nullptr);
}

void Instance::Private::importDone(const MTPauth_Authorization &result, mtpRequestId requestId) {
	QMutexLocker locker1(&_requestByDcLock);

	auto it = _requestsByDc.find(requestId);
	if (it == _requestsByDc.end()) {
		LOG(("MTP Error: auth import request not found in requestsByDC, requestId: %1").arg(requestId));
		RPCError error(internal::rpcClientError("AUTH_IMPORT_FAIL", QString("did not find import request in requestsByDC, request %1").arg(requestId)));
		if (_globalHandler.onFail && hasAuthorization()) {
			(*_globalHandler.onFail)(requestId, error); // auth failed in main dc
		}
		return;
	}
	auto newdc = bareDcId(it->second);

	DEBUG_LOG(("MTP Info: auth import to dc %1 succeeded").arg(newdc));

	auto &waiters = _authWaiters[newdc];
	if (waiters.size()) {
		QReadLocker locker(&_requestMapLock);
		for (auto waitedRequestId : waiters) {
			auto it = _requestMap.find(waitedRequestId);
			if (it == _requestMap.cend()) {
				LOG(("MTP Error: could not find request %1 for resending").arg(waitedRequestId));
				continue;
			}
			auto dcWithShift = ShiftedDcId(newdc);
			{
				auto k = _requestsByDc.find(waitedRequestId);
				if (k == _requestsByDc.cend()) {
					LOG(("MTP Error: could not find request %1 by dc for resending").arg(waitedRequestId));
					continue;
				}
				if (k->second < 0) {
					_instance->setMainDcId(newdc);
					k->second = -newdc;
				} else {
					dcWithShift = shiftDcId(newdc, getDcIdShift(k->second));
					k->second = dcWithShift;
				}
				DEBUG_LOG(("MTP Info: resending request %1 to dc %2 after import auth").arg(waitedRequestId).arg(k->second));
			}
			if (auto session = getSession(dcWithShift)) {
				session->sendPrepared(it->second);
			}
		}
		waiters.clear();
	}
}

bool Instance::Private::importFail(const RPCError &error, mtpRequestId requestId) {
	if (isDefaultHandledError(error)) return false;

	if (_globalHandler.onFail && hasAuthorization()) {
		(*_globalHandler.onFail)(requestId, error); // auth import failed
	}
	return true;
}

void Instance::Private::exportDone(const MTPauth_ExportedAuthorization &result, mtpRequestId requestId) {
	auto it = _authExportRequests.find(requestId);
	if (it == _authExportRequests.cend()) {
		LOG(("MTP Error: auth export request target dcWithShift not found, requestId: %1").arg(requestId));
		RPCError error(internal::rpcClientError("AUTH_IMPORT_FAIL", QString("did not find target dcWithShift, request %1").arg(requestId)));
		if (_globalHandler.onFail && hasAuthorization()) {
			(*_globalHandler.onFail)(requestId, error); // auth failed in main dc
		}
		return;
	}

	auto &data = result.c_auth_exportedAuthorization();
	_instance->send(MTPauth_ImportAuthorization(data.vid, data.vbytes), rpcDone([this](const MTPauth_Authorization &result, mtpRequestId requestId) {
		importDone(result, requestId);
	}), rpcFail([this](const RPCError &error, mtpRequestId requestId) {
		return importFail(error, requestId);
	}), it->second);
	_authExportRequests.erase(requestId);
}

bool Instance::Private::exportFail(const RPCError &error, mtpRequestId requestId) {
	if (isDefaultHandledError(error)) return false;

	auto it = _authExportRequests.find(requestId);
	if (it != _authExportRequests.cend()) {
		_authWaiters[bareDcId(it->second)].clear();
	}
	if (_globalHandler.onFail && hasAuthorization()) {
		(*_globalHandler.onFail)(requestId, error); // auth failed in main dc
	}
	return true;
}

bool Instance::Private::onErrorDefault(mtpRequestId requestId, const RPCError &error) {
	auto &err(error.type());
	auto code = error.code();
	if (!isFloodError(error) && err != qstr("AUTH_KEY_UNREGISTERED")) {
		int breakpoint = 0;
	}
	auto badGuestDc = (code == 400) && (err == qsl("FILE_ID_INVALID"));
	QRegularExpressionMatch m;
	if ((m = QRegularExpression("^(FILE|PHONE|NETWORK|USER)_MIGRATE_(\\d+)$").match(err)).hasMatch()) {
		if (!requestId) return false;

		ShiftedDcId dcWithShift = 0, newdcWithShift = m.captured(2).toInt();
		{
			QMutexLocker locker(&_requestByDcLock);
			auto it = _requestsByDc.find(requestId);
			if (it == _requestsByDc.end()) {
				LOG(("MTP Error: could not find request %1 for migrating to %2").arg(requestId).arg(newdcWithShift));
			} else {
				dcWithShift = it->second;
			}
		}
		if (!dcWithShift || !newdcWithShift) return false;

		DEBUG_LOG(("MTP Info: changing request %1 from dcWithShift%2 to dc%3").arg(requestId).arg(dcWithShift).arg(newdcWithShift));
		if (dcWithShift < 0) { // newdc shift = 0
			if (false && hasAuthorization() && _authExportRequests.find(requestId) == _authExportRequests.cend()) {
				//
				// migrate not supported at this moment
				// this was not tested even once
				//
				//DEBUG_LOG(("MTP Info: importing auth to dc %1").arg(newdcWithShift));
				//auto &waiters(_authWaiters[newdcWithShift]);
				//if (waiters.empty()) {
				//	auto exportRequestId = _instance->send(MTPauth_ExportAuthorization(MTP_int(newdcWithShift)), rpcDone([this](const MTPauth_ExportedAuthorization &result, mtpRequestId requestId) {
				//		exportDone(result, requestId);
				//	}), rpcFail([this](const RPCError &error, mtpRequestId requestId) {
				//		return exportFail(error, requestId);
				//	}));
				//	_authExportRequests.emplace(exportRequestId, newdcWithShift);
				//}
				//waiters.push_back(requestId);
				//return true;
			} else {
				_instance->setMainDcId(newdcWithShift);
			}
		} else {
			newdcWithShift = shiftDcId(newdcWithShift, getDcIdShift(dcWithShift));
		}

		auto request = mtpRequest();
		{
			QReadLocker locker(&_requestMapLock);
			auto it = _requestMap.find(requestId);
			if (it == _requestMap.cend()) {
				LOG(("MTP Error: could not find request %1").arg(requestId));
				return false;
			}
			request = it->second;
		}
		if (auto session = getSession(newdcWithShift)) {
			registerRequest(requestId, (dcWithShift < 0) ? -newdcWithShift : newdcWithShift);
			session->sendPrepared(request);
		}
		return true;
	} else if (code < 0 || code >= 500 || (m = QRegularExpression("^FLOOD_WAIT_(\\d+)$").match(err)).hasMatch()) {
		if (!requestId) return false;

		int32 secs = 1;
		if (code < 0 || code >= 500) {
			auto it = _requestsDelays.find(requestId);
			if (it != _requestsDelays.cend()) {
				secs = (it->second > 60) ? it->second : (it->second *= 2);
			} else {
				_requestsDelays.emplace(requestId, secs);
			}
		} else {
			secs = m.captured(1).toInt();
//			if (secs >= 60) return false;
		}
		auto sendAt = getms(true) + secs * 1000 + 10;
		auto it = _delayedRequests.begin(), e = _delayedRequests.end();
		for (; it != e; ++it) {
			if (it->first == requestId) return true;
			if (it->second > sendAt) break;
		}
		_delayedRequests.insert(it, std::make_pair(requestId, sendAt));

		checkDelayedRequests();

		return true;
	} else if (code == 401 || (badGuestDc && _badGuestDcRequests.find(requestId) == _badGuestDcRequests.cend())) {
		auto dcWithShift = ShiftedDcId(0);
		{
			QMutexLocker locker(&_requestByDcLock);
			auto it = _requestsByDc.find(requestId);
			if (it != _requestsByDc.end()) {
				dcWithShift = it->second;
			} else {
				LOG(("MTP Error: unauthorized request without dc info, requestId %1").arg(requestId));
			}
		}
		auto newdc = bareDcId(qAbs(dcWithShift));
		if (!newdc || newdc == mainDcId() || !hasAuthorization()) {
			if (!badGuestDc && _globalHandler.onFail) {
				(*_globalHandler.onFail)(requestId, error); // auth failed in main dc
			}
			return false;
		}

		DEBUG_LOG(("MTP Info: importing auth to dcWithShift %1").arg(dcWithShift));
		auto &waiters(_authWaiters[newdc]);
		if (!waiters.size()) {
			auto exportRequestId = _instance->send(MTPauth_ExportAuthorization(MTP_int(newdc)), rpcDone([this](const MTPauth_ExportedAuthorization &result, mtpRequestId requestId) {
				exportDone(result, requestId);
			}), rpcFail([this](const RPCError &error, mtpRequestId requestId) {
				return exportFail(error, requestId);
			}));
			_authExportRequests.emplace(exportRequestId, abs(dcWithShift));
		}
		waiters.push_back(requestId);
		if (badGuestDc) _badGuestDcRequests.insert(requestId);
		return true;
	} else if (err == qstr("CONNECTION_NOT_INITED") || err == qstr("CONNECTION_LAYER_INVALID")) {
		mtpRequest request;
		{
			QReadLocker locker(&_requestMapLock);
			auto it = _requestMap.find(requestId);
			if (it == _requestMap.cend()) {
				LOG(("MTP Error: could not find request %1").arg(requestId));
				return false;
			}
			request = it->second;
		}
		auto dcWithShift = ShiftedDcId(0);
		{
			QMutexLocker locker(&_requestByDcLock);
			auto it = _requestsByDc.find(requestId);
			if (it == _requestsByDc.end()) {
				LOG(("MTP Error: could not find request %1 for resending with init connection").arg(requestId));
			} else {
				dcWithShift = it->second;
			}
		}
		if (!dcWithShift) return false;

		if (auto session = getSession(qAbs(dcWithShift))) {
			request->needsLayer = true;
			session->sendPrepared(request);
		}
		return true;
	} else if (err == qstr("MSG_WAIT_FAILED")) {
		mtpRequest request;
		{
			QReadLocker locker(&_requestMapLock);
			auto it = _requestMap.find(requestId);
			if (it == _requestMap.cend()) {
				LOG(("MTP Error: could not find request %1").arg(requestId));
				return false;
			}
			request = it->second;
		}
		if (!request->after) {
			LOG(("MTP Error: wait failed for not dependent request %1").arg(requestId));
			return false;
		}
		auto dcWithShift = ShiftedDcId(0);
		{
			QMutexLocker locker(&_requestByDcLock);
			auto it = _requestsByDc.find(requestId);
			auto afterIt = _requestsByDc.find(request->after->requestId);
			if (it == _requestsByDc.end()) {
				LOG(("MTP Error: could not find request %1 by dc").arg(requestId));
			} else if (afterIt == _requestsByDc.end()) {
				LOG(("MTP Error: could not find dependent request %1 by dc").arg(request->after->requestId));
			} else {
				dcWithShift = it->second;
				if (it->second != afterIt->second) {
					request->after = mtpRequest();
				}
			}
		}
		if (!dcWithShift) return false;

		if (!request->after) {
			if (auto session = getSession(qAbs(dcWithShift))) {
				request->needsLayer = true;
				session->sendPrepared(request);
			}
		} else {
			auto newdc = bareDcId(qAbs(dcWithShift));
			auto &waiters(_authWaiters[newdc]);
			if (base::contains(waiters, request->after->requestId)) {
				if (!base::contains(waiters, requestId)) {
					waiters.push_back(requestId);
				}
				if (_badGuestDcRequests.find(request->after->requestId) != _badGuestDcRequests.cend()) {
					if (_badGuestDcRequests.find(requestId) == _badGuestDcRequests.cend()) {
						_badGuestDcRequests.insert(requestId);
					}
				}
			} else {
				auto i = _delayedRequests.begin(), e = _delayedRequests.end();
				for (; i != e; ++i) {
					if (i->first == requestId) return true;
					if (i->first == request->after->requestId) break;
				}
				if (i != e) {
					_delayedRequests.insert(i, std::make_pair(requestId, i->second));
				}

				checkDelayedRequests();
			}
		}
		return true;
	}
	if (badGuestDc) _badGuestDcRequests.erase(requestId);
	return false;
}

internal::Session *Instance::Private::getSession(ShiftedDcId shiftedDcId) {
	if (!shiftedDcId) {
		t_assert(_mainSession != nullptr);
		return _mainSession;
	}
	if (!bareDcId(shiftedDcId)) {
		t_assert(_mainSession != nullptr);
		shiftedDcId += bareDcId(_mainSession->getDcWithShift());
	}

	auto it = _sessions.find(shiftedDcId);
	if (it == _sessions.cend()) {
		it = _sessions.emplace(shiftedDcId, std::make_unique<internal::Session>(_instance, shiftedDcId)).first;
	}
	return it->second.get();
}

void Instance::Private::setUpdatesHandler(RPCDoneHandlerPtr onDone) {
	_globalHandler.onDone = onDone;
}

void Instance::Private::setGlobalFailHandler(RPCFailHandlerPtr onFail) {
	_globalHandler.onFail = onFail;
}

void Instance::Private::setStateChangedHandler(base::lambda<void(ShiftedDcId shiftedDcId, int32 state)> &&handler) {
	_stateChangedHandler = std::move(handler);
}

void Instance::Private::setSessionResetHandler(base::lambda<void(ShiftedDcId shiftedDcId)> &&handler) {
	_sessionResetHandler = std::move(handler);
}

void Instance::Private::clearGlobalHandlers() {
	setUpdatesHandler(RPCDoneHandlerPtr());
	setGlobalFailHandler(RPCFailHandlerPtr());
	setStateChangedHandler(base::lambda<void(ShiftedDcId,int32)>());
	setSessionResetHandler(base::lambda<void(ShiftedDcId)>());
}

Instance::Private::~Private() {
	for (auto &session : base::take(_sessions)) {
		session.second->kill();
	}
}

Instance::Instance(DcOptions *options, Config &&config) : QObject()
, _private(std::make_unique<Private>(this, options)) {
	_private->start(std::move(config));
}

void Instance::suggestMainDcId(DcId mainDcId) {
	_private->suggestMainDcId(mainDcId);
}

void Instance::setMainDcId(DcId mainDcId) {
	_private->setMainDcId(mainDcId);
}

DcId Instance::mainDcId() const {
	return _private->mainDcId();
}

void Instance::configLoadRequest() {
	_private->configLoadRequest();
}

void Instance::connectionFinished(internal::Connection *connection) {
	_private->connectionFinished(connection);
}

void Instance::restart() {
	_private->restart();
}

void Instance::restart(ShiftedDcId shiftedDcId) {
	_private->restart(shiftedDcId);
}

int32 Instance::dcstate(ShiftedDcId shiftedDcId) {
	return _private->dcstate(shiftedDcId);
}

QString Instance::dctransport(ShiftedDcId shiftedDcId) {
	return _private->dctransport(shiftedDcId);
}

void Instance::ping() {
	_private->ping();
}

void Instance::cancel(mtpRequestId requestId) {
	_private->cancel(requestId);
}

int32 Instance::state(mtpRequestId requestId) { // < 0 means waiting for such count of ms
	return _private->state(requestId);
}

void Instance::killSession(ShiftedDcId shiftedDcId) {
	_private->killSession(shiftedDcId);
}

void Instance::stopSession(ShiftedDcId shiftedDcId) {
	_private->stopSession(shiftedDcId);
}

void Instance::logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail) {
	_private->logout(onDone, onFail);
}

internal::DcenterPtr Instance::getDcById(DcId dcId) {
	return _private->getDcById(dcId);
}

void Instance::setKeyForWrite(DcId dcId, const AuthKeyPtr &key) {
	_private->setKeyForWrite(dcId, key);
}

AuthKeysMap Instance::getKeysForWrite() const {
	return _private->getKeysForWrite();
}

DcOptions *Instance::dcOptions() {
	return _private->dcOptions();
}

void Instance::unpaused() {
	_private->unpaused();
}

void Instance::queueQuittingConnection(std::unique_ptr<internal::Connection> connection) {
	_private->queueQuittingConnection(std::move(connection));
}

void Instance::setUpdatesHandler(RPCDoneHandlerPtr onDone) {
	_private->setUpdatesHandler(onDone);
}

void Instance::setGlobalFailHandler(RPCFailHandlerPtr onFail) {
	_private->setGlobalFailHandler(onFail);
}

void Instance::setStateChangedHandler(base::lambda<void(ShiftedDcId shiftedDcId, int32 state)> &&handler) {
	_private->setStateChangedHandler(std::move(handler));
}

void Instance::setSessionResetHandler(base::lambda<void(ShiftedDcId shiftedDcId)> &&handler) {
	_private->setSessionResetHandler(std::move(handler));
}

void Instance::clearGlobalHandlers() {
	_private->clearGlobalHandlers();
}

void Instance::onStateChange(ShiftedDcId dcWithShift, int32 state) {
	_private->onStateChange(dcWithShift, state);
}

void Instance::onSessionReset(ShiftedDcId dcWithShift) {
	_private->onSessionReset(dcWithShift);
}

void Instance::registerRequest(mtpRequestId requestId, ShiftedDcId dcWithShift) {
	_private->registerRequest(requestId, dcWithShift);
}

mtpRequestId Instance::storeRequest(mtpRequest &request, const RPCResponseHandler &parser) {
	return _private->storeRequest(request, parser);
}

mtpRequest Instance::getRequest(mtpRequestId requestId) {
	return _private->getRequest(requestId);
}

void Instance::clearCallbacksDelayed(const RPCCallbackClears &requestIds) {
	_private->clearCallbacksDelayed(requestIds);
}

void Instance::execCallback(mtpRequestId requestId, const mtpPrime *from, const mtpPrime *end) {
	_private->execCallback(requestId, from, end);
}

bool Instance::hasCallbacks(mtpRequestId requestId) {
	return _private->hasCallbacks(requestId);
}

void Instance::globalCallback(const mtpPrime *from, const mtpPrime *end) {
	_private->globalCallback(from, end);
}

bool Instance::rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err) {
	return _private->rpcErrorOccured(requestId, onFail, err);
}

internal::Session *Instance::getSession(ShiftedDcId shiftedDcId) {
	return _private->getSession(shiftedDcId);
}

Instance::~Instance() = default;

} // namespace MTP