/**
 * Copyright - See the COPYRIGHT that is included with this distribution.
 * pvAccessCPP is distributed subject to a Software License Agreement found
 * in file LICENSE that is included with this distribution.
 */

#ifdef _WIN32
#define NOMINMAX
#endif

#include <pv/beaconEmitter.h>
#include <pv/serializationHelper.h>

#include <pv/logger.h>
#include <algorithm>

#include <pv/serverContext.h>

using namespace std;
using namespace epics::pvData;

namespace epics { namespace pvAccess {

const float BeaconEmitter::EPICS_PVA_MIN_BEACON_PERIOD = 1.0;
const float BeaconEmitter::EPICS_PVA_MIN_BEACON_COUNT_LIMIT = 3.0;

//BeaconEmitter::BeaconEmitter(Transport::shared_pointer const & transport, ServerContextImpl::shared_pointer const & context) :
BeaconEmitter::BeaconEmitter(std::string const & protocol,
    Transport::shared_pointer const & transport, std::tr1::shared_ptr<ServerContextImpl>& context) :
    _protocol(protocol),
    _transport(transport),
    _beaconSequenceID(0),
    _guid(context->getGUID()),
    _fastBeaconPeriod(std::max(context->getBeaconPeriod(), EPICS_PVA_MIN_BEACON_PERIOD)),
    _slowBeaconPeriod(std::max(180.0, _fastBeaconPeriod)), // TODO configurable
    _beaconCountLimit((int16)std::max(10.0f, EPICS_PVA_MIN_BEACON_COUNT_LIMIT)), // TODO configurable
    _serverAddress(*(context->getServerInetAddress())),
    _serverPort(context->getServerPort()),
    _serverStatusProvider(context->getBeaconServerStatusProvider()),
    _timer(context->getTimer())
{
}

BeaconEmitter::~BeaconEmitter()
{
	// shared_from_this is not yet allows in destructor
	// be sure to call destroy() first !!!
	// destroy();
}

void BeaconEmitter::lock()
{
	//noop
}

void BeaconEmitter::unlock()
{
	//noop
}

void BeaconEmitter::send(ByteBuffer* buffer, TransportSendControl* control)
{
	// get server status
	PVField::shared_pointer serverStatus;
	if(_serverStatusProvider.get())
	{
		try
		{
			serverStatus = _serverStatusProvider->getServerStatusData();
		}
		catch (...) {
			// we have to proctect internal code from external implementation...
			LOG(logLevelDebug, "BeaconServerStatusProvider implementation thrown an exception.");
		}
	}

	// send beacon
	control->startMessage((int8)0, 12+2+2+16+2);

    buffer->put(_guid.value, 0, sizeof(_guid.value));

    // TODO qos/flags (e.g. multicast/unicast)
    buffer->putByte(0);

    buffer->putByte(_beaconSequenceID);

	// TODO for now fixed changeCount
	buffer->putShort(0);

	// NOTE: is it possible (very likely) that address is any local address ::ffff:0.0.0.0
	encodeAsIPv6Address(buffer, &_serverAddress);
	buffer->putShort((int16)_serverPort);

    SerializeHelper::serializeString(_protocol, buffer, control);

	if (serverStatus)
	{
		// introspection interface + data
		serverStatus->getField()->serialize(buffer, control);
		serverStatus->serialize(buffer, control);
	}
	else
	{
        SerializationHelper::serializeNullField(buffer, control);
	}
	control->flush(true);

	// increment beacon sequence ID
	_beaconSequenceID++;

	reschedule();
}

void BeaconEmitter::timerStopped()
{
	//noop
}

void BeaconEmitter::destroy()
{
    _timer->cancel(shared_from_this());
}

void BeaconEmitter::start()
{
    _timer->scheduleAfterDelay(shared_from_this(), 0.0);
}

void BeaconEmitter::reschedule()
{
    const double period = (_beaconSequenceID >= _beaconCountLimit) ? _slowBeaconPeriod : _fastBeaconPeriod;
	if (period > 0)
	{
        _timer->scheduleAfterDelay(shared_from_this(), period);
	}
}

void BeaconEmitter::callback()
{
	_transport->enqueueSendRequest(shared_from_this());
}

}}