#include <QtCore/QDebug>
#include <QtCore/QTimerEvent>

#include "sappeer.h"
#include "sapconnection.h"
#include "sapsocket.h"

#define DELAYED_ACK_TIME 1000

SAPSocket::SAPSocket(SAPConnection *conn, int sessionId, const SAPChannelInfo &chanInfo) :
	QObject(conn), _sessionId(sessionId), _info(chanInfo), _open(false),
	_outLastSeqNum(0), _inLastSeqNum(0), _inLastAck(0)
{
}

SAPPeer * SAPSocket::peer()
{
	return connection()->peer();
}

SAPConnection * SAPSocket::connection()
{
	return static_cast<SAPConnection*>(parent());
}

SAPChannelInfo SAPSocket::channelInfo() const
{
	return _info;
}

bool SAPSocket::isOpen() const
{
	return _open;
}

bool SAPSocket::messageAvailable() const
{
	return !_in.empty();
}

QByteArray SAPSocket::receive()
{
	if (!_in.empty()) {
		return _in.dequeue();
	} else {
		return QByteArray();
	}
}

bool SAPSocket::send(const QByteArray &data)
{
	SAProtocol::DataFrame frame;

	if (!isOpen()) {
		qWarning() << "Socket is not yet open";
		return false;
	}

	frame.withSeqNum = isWithSeqNum();
	if (isReliable()) {
		frame.seqNum = ++_outLastSeqNum;
	} else {
		frame.seqNum = 0;
	}
	frame.unk_1 = 0;
	frame.data = data;

	peer()->writeDataToSession(_sessionId, SAProtocol::packDataFrame(frame));
	return true;
}

void SAPSocket::setOpen(bool open)
{
	_open = open;
}

void SAPSocket::acceptIncomingData(const QByteArray &data)
{
	if (data.isEmpty()) return;
	SAProtocol::DataFrame frame = SAProtocol::unpackDataFrame(data, isWithSeqNum());

	if (isReliable()) {
		quint16 expectedSeqNum = _inLastSeqNum + 1;
		if (frame.seqNum != expectedSeqNum) {
			qWarning() << "Unexpected sequence number" << frame.seqNum
					   << "on session" << _sessionId
					   << "(expected " << expectedSeqNum << ")";
		} else {
			_inLastSeqNum = frame.seqNum;

			if (!_timer.isActive()) {
				_timer.start(DELAYED_ACK_TIME, Qt::CoarseTimer, this);
			}
		}
	}

	_in.enqueue(frame.data);

	emit messageReceived();
}

int SAPSocket::sessionId() const
{
	return _sessionId;
}

void SAPSocket::timerEvent(QTimerEvent *event)
{
	if (event->timerId() == _timer.timerId()) {
		if (_inLastSeqNum != _inLastAck) {
			peer()->writeAckToSession(_sessionId, _inLastSeqNum);
			_inLastAck = _inLastSeqNum;
		}
		_timer.stop();
	} else {
		QObject::timerEvent(event);
	}
}

bool SAPSocket::isReliable() const
{
	return _info.qosType() == SAPChannelInfo::QoSReliabilityEnable;
}

bool SAPSocket::isWithSeqNum() const
{
	return _info.qosType() == SAPChannelInfo::QoSReliabilityDisable ||
		   _info.qosType() == SAPChannelInfo::QoSReliabilityEnable;
}