/* Copyright (C) 2005-2007, Thorvald Natvig <thorvald@natvig.com>

   All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:

   - Redistributions of source code must retain the above copyright notice,
     this list of conditions and the following disclaimer.
   - Redistributions in binary form must reproduce the above copyright notice,
     this list of conditions and the following disclaimer in the documentation
     and/or other materials provided with the distribution.
   - Neither the name of the Mumble Developers nor the names of its
     contributors may be used to endorse or promote products derived from this
     software without specific prior written permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include "Message.h"
#include "Connection.h"
#include "PacketDataStream.h"

#ifdef Q_OS_UNIX
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#endif
#ifdef Q_OS_WIN
#include <winsock2.h>
#endif

int Connection::iReceiveLevel = 0;
QSet<Connection *> Connection::qsReceivers;

Connection::Connection(QObject *p, QSslSocket *qtsSock) : QObject(p) {
	qtsSocket = qtsSock;
	qtsSocket->setParent(this);
	iPacketLength = -1;
	bDisconnectedEmitted = false;

	dUDPPingAvg = dUDPPingVar = 0.0L;
	dTCPPingAvg = dTCPPingVar = 0.0L;
	uiUDPPackets = uiTCPPackets = 0;

	connect(qtsSocket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(socketError(QAbstractSocket::SocketError)));
	connect(qtsSocket, SIGNAL(readyRead()), this, SLOT(socketRead()));
	connect(qtsSocket, SIGNAL(disconnected()), this, SLOT(socketDisconnected()));
	connect(qtsSocket, SIGNAL(sslErrors(const QList<QSslError> &)), this, SLOT(socketSslErrors(const QList<QSslError> &)));
	qtLastPacket.restart();
}

Connection::~Connection() {
	qsReceivers.remove(this);
}

int Connection::activityTime() const {
	return qtLastPacket.elapsed();
}

void Connection::socketRead() {
	// QSslSocket will, during writes, emit readyRead. Meaning we'd reenter from the message handlers.
	// At the same time, DBus connections don't like getting multiple concurrent requests.
	// So, this is a big workaround to serialize user requests.

	int iPrevLevel = iReceiveLevel;

	iReceiveLevel = 2;

	if (iPrevLevel == 2) {
		// Recursive entry. Put on list and ignore.
		qsReceivers.insert(this);
		return;
	} else if (iPrevLevel == 1) {
		// We're iterating from the topmost one.
		qsReceivers.remove(this);
	}

	int iAvailable = qtsSocket->bytesAvailable();

	if (iPacketLength == -1) {
		if (iAvailable < 3) {
			iReceiveLevel = iPrevLevel;
			return;
		}

		unsigned char a_ucBuffer[3];

		qtsSocket->read(reinterpret_cast<char *>(a_ucBuffer), 3);
		iPacketLength = ((a_ucBuffer[0] << 16) & 0xff0000) + ((a_ucBuffer[1] << 8) & 0xff00) + a_ucBuffer[2];
		iAvailable -= 3;
	}

	if ((iPacketLength != -1) && (iAvailable >= iPacketLength)) {
		QByteArray qbaBuffer = qtsSocket->read(iPacketLength);
		iPacketLength = -1;
		qtLastPacket.restart();
		iAvailable -= iPacketLength;
		if (iAvailable >= 3)
			qsReceivers.insert(this);

		emit message(qbaBuffer);
	}

	// At this point, the current *this might be destroyed.

	if (iPrevLevel == 0) {
		iReceiveLevel = 1;
		QSet<Connection *>::const_iterator i = qsReceivers.constBegin();
		while (i != qsReceivers.constEnd()) {
			(*i)->socketRead();
			i = qsReceivers.constBegin();
		}
	}
	iReceiveLevel = iPrevLevel;
}

void Connection::socketError(QAbstractSocket::SocketError) {
	if (! bDisconnectedEmitted) {
		bDisconnectedEmitted = true;
		emit connectionClosed(qtsSocket->errorString());
	}
}

void Connection::socketSslErrors(const QList<QSslError> &qlErr) {
	emit handleSslErrors(qlErr);
}

void Connection::proceedAnyway() {
	qtsSocket->ignoreSslErrors();
}

void Connection::socketDisconnected() {
	if (! bDisconnectedEmitted) {
		bDisconnectedEmitted = true;
		emit connectionClosed(QString());
	}
}

void Connection::sendMessage(const Message *mMsg) {
	QByteArray qbaBuffer;
	mMsg->messageToNetwork(qbaBuffer);

	sendMessage(qbaBuffer);
}

void Connection::sendMessage(const QByteArray &qbaMsg) {
	unsigned char a_ucBuffer[3 + qbaMsg.size()];

	if (qtsSocket->state() != QAbstractSocket::ConnectedState)
		return;

	if (! qtsSocket->isEncrypted())
		return;

	if (qbaMsg.size() > 0xfffff) {
		qFatal("Connection: Oversized message (%d bytes)", qbaMsg.size());
	}

	a_ucBuffer[0]=(qbaMsg.size() >> 16) & 0xff;
	a_ucBuffer[1]=(qbaMsg.size() >> 8) & 0xff;
	a_ucBuffer[2]=(qbaMsg.size() & 0xff);
	memcpy(a_ucBuffer + 3, qbaMsg.constData(), qbaMsg.size());

	int iPrevLevel = iReceiveLevel;
	iReceiveLevel = 2;

	qtsSocket->write(reinterpret_cast<const char *>(a_ucBuffer), 3 + qbaMsg.size());

	if (iPrevLevel == 0) {
		iReceiveLevel = 1;
		QSet<Connection *>::const_iterator i = qsReceivers.constBegin();
		while (i != qsReceivers.constEnd()) {
			(*i)->socketRead();
			i = qsReceivers.constBegin();
		}
	}
	iReceiveLevel = iPrevLevel;
}

void Connection::forceFlush() {
	if (qtsSocket->state() != QAbstractSocket::ConnectedState)
		return;

	if (! qtsSocket->isEncrypted())
		return;

	int nodelay;

	qtsSocket->flush();

	nodelay = 1;
	setsockopt(qtsSocket->socketDescriptor(), IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&nodelay), sizeof(nodelay));
	nodelay = 0;
	setsockopt(qtsSocket->socketDescriptor(), IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&nodelay), sizeof(nodelay));
}

void Connection::disconnectSocket() {
	qtsSocket->disconnectFromHost();
}

void Connection::updatePing(double &avg, double &var, quint32 &samples, quint64 usec) {
	samples++;
	double x = usec / 1000.0L;
	double delta = x - avg;
	avg += delta / (samples * 1.0L);
	var += delta * (x - avg);
};

QHostAddress Connection::peerAddress() const {
	return qtsSocket->peerAddress();
}

quint16 Connection::peerPort() const {
	return qtsSocket->peerPort();
}

QList<QSslCertificate> Connection::peerCertificateChain() const {
	return qtsSocket->peerCertificateChain();
}

QSslCipher Connection::sessionCipher() const {
	return qtsSocket->sessionCipher();
}