//
// This file is part of Kepka,
// an unofficial desktop version of Telegram messaging app,
// see https://github.com/procxx/kepka
//
// Kepka 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/procxx/kepka/blob/master/LICENSE
// Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
// Copyright (c) 2017- Kepka Contributors, https://github.com/procxx
//
#pragma once

#include "mtproto/auth_key.h"
#include "mtproto/connection_abstract.h"

#include <QAbstractSocket>
#include <QTcpSocket>
#include <QTimer>

namespace MTP {
namespace internal {

class AbstractTCPConnection : public AbstractConnection {
	Q_OBJECT

public:
	AbstractTCPConnection(QThread *thread);
	virtual ~AbstractTCPConnection() = 0;

public slots:

	void socketRead();

protected:
	QTcpSocket sock;
	quint32 packetNum; // sent packet number

	quint32 packetRead, packetLeft; // reading from socket
	bool readingToShort;
	char *currentPos;
	mtpBuffer longBuffer;
	mtpPrime shortBuffer[MTPShortBufferSize];
	virtual void socketPacket(const char *packet, quint32 length) = 0;

	static mtpBuffer handleResponse(const char *packet, quint32 length);
	static void handleError(QAbstractSocket::SocketError e, QTcpSocket &sock);
	static quint32 fourCharsToUInt(char ch1, char ch2, char ch3, char ch4) {
		char ch[4] = {ch1, ch2, ch3, ch4};
		return *reinterpret_cast<quint32 *>(ch);
	}

	void tcpSend(mtpBuffer &buffer);
	uchar _sendKey[CTRState::KeySize];
	CTRState _sendState;
	uchar _receiveKey[CTRState::KeySize];
	CTRState _receiveState;
};

class TCPConnection : public AbstractTCPConnection {
	Q_OBJECT

public:
	TCPConnection(QThread *thread);

	void sendData(mtpBuffer &buffer) override;
	void disconnectFromServer() override;
	void connectTcp(const DcOptions::Endpoint &endpoint) override;
	void connectHttp(const DcOptions::Endpoint &endpoint) override { // not supported
	}
	bool isConnected() const override;

	qint32 debugState() const override;

	QString transport() const override;

public slots:

	void socketError(QAbstractSocket::SocketError e);

	void onSocketConnected();
	void onSocketDisconnected();

	void onTcpTimeoutTimer();

protected:
	void socketPacket(const char *packet, quint32 length) override;

private:
	enum Status { WaitingTcp = 0, UsingTcp, FinishedWork };
	Status status;
	MTPint128 tcpNonce;

	QString _addr;
	qint32 _port, _tcpTimeout;
	MTPDdcOption::Flags _flags;
	QTimer tcpTimeoutTimer;
};

} // namespace internal
} // namespace MTP