bool recvGift(NETQUEUE queue)
{
	uint8_t	type, from, to;
	int		audioTrack;
	uint32_t droidID;

	NETbeginDecode(queue, GAME_GIFT);
	NETuint8_t(&type);
	NETuint8_t(&from);
	NETuint8_t(&to);
	NETuint32_t(&droidID);
	NETend();

	if (!canGiveOrdersFor(queue.index, from))
	{
		debug(LOG_WARNING, "Gift (%d) from %d, to %d, queue.index %d", (int)type, (int)from, (int)to, (int)queue.index);
		syncDebug("Wrong player.");
		return false;
	}

	// Handle the gift depending on what it is
	switch (type)
	{
	case RADAR_GIFT:
		audioTrack = ID_SENSOR_DOWNLOAD;
		giftRadar(from, to, false);
		break;
	case DROID_GIFT:
		audioTrack = ID_UNITS_TRANSFER;
		recvGiftDroids(from, to, droidID);
		break;
	case STRUCTURE_GIFT:
		audioTrack = ID_GIFT;
		recvGiftStruct(from, to, droidID);
		break;
	case RESEARCH_GIFT:
		audioTrack = ID_TECHNOLOGY_TRANSFER;
		giftResearch(from, to, false);
		break;
	case POWER_GIFT:
		audioTrack = ID_POWER_TRANSMIT;
		giftPower(from, to, droidID, false);
		break;
	case AUTOGAME_GIFT:
		audioTrack = ID_SOUND_NEXUS_SYNAPTIC_LINK;
		giftAutoGame(from, to, false);
		break;
	default:
		debug(LOG_ERROR, "recvGift: Unknown Gift recvd");
		return false;
		break;
	}

	// If we are on the receiving end play an audio alert.
	if (bMultiPlayer && to == selectedPlayer)
	{
		audio_QueueTrack(audioTrack);
	}
	return true;
}

// ////////////////////////////////////////////////////////////////////////////
// give technologies.
static void giftResearch(uint8_t from, uint8_t to, bool send)
{
	int		i;
	uint32_t	dummy = 0;

	if (send)
	{
		uint8_t giftType = RESEARCH_GIFT;

		NETbeginEncode(NETgameQueue(selectedPlayer), GAME_GIFT);
		NETuint8_t(&giftType);
		NETuint8_t(&from);
		NETuint8_t(&to);
		NETuint32_t(&dummy);
		NETend();
	}
	else if (alliancesCanGiveResearchAndRadar(game.alliance))
	{
		if (to == selectedPlayer)
		{
			CONPRINTF(ConsoleString, (ConsoleString, _("%s Gives You Technology Documents"), getPlayerName(from)));
		}
		// For each topic
		for (i = 0; i < asResearch.size(); i++)
		{
			// If they have it and we don't research it
			if (IsResearchCompleted(&asPlayerResList[from][i])
			    && !IsResearchCompleted(&asPlayerResList[to][i]))
			{
				MakeResearchCompleted(&asPlayerResList[to][i]);
				researchResult(i, to, false, NULL, true);
			}
		}
	}
}

// ////////////////////////////////////////////////////////////////////////////
// give radar information
void giftRadar(uint8_t from, uint8_t to, bool send)
{
	uint32_t dummy = 0;

	if (send)
	{
		uint8_t subType = RADAR_GIFT;

		NETbeginEncode(NETgameQueue(selectedPlayer), GAME_GIFT);
		NETuint8_t(&subType);
		NETuint8_t(&from);
		NETuint8_t(&to);
		NETuint32_t(&dummy);
		NETend();
	}
	// If we are recieving the gift
	else
	{
		hqReward(from, to);
		if (to == selectedPlayer)
		{
			CONPRINTF(ConsoleString, (ConsoleString, _("%s Gives You A Visibility Report"), getPlayerName(from)));
		}
	}
}

BOOL recvAlliance(BOOL allowAudio)
{
	uint8_t to, from, state;
	int32_t value;

	NETbeginDecode(NET_ALLIANCE);
		NETuint8_t(&from);
		NETuint8_t(&to);
		NETuint8_t(&state);
		NETint32_t(&value);
	NETend();

	switch (state)
	{
		case ALLIANCE_NULL:
			break;
		case ALLIANCE_REQUESTED:
			requestAlliance(from, to, false, allowAudio);
			break;
		case ALLIANCE_FORMED:
			formAlliance(from, to, false, allowAudio, true);
			break;
		case ALLIANCE_BROKEN:
			breakAlliance(from, to, false, allowAudio);
			break;
		default:
			debug(LOG_ERROR, "Unknown alliance state recvd.");
			return false;
			break;
	}

	return true;
}

// recv lassat info on the receiving end.
BOOL recvLasSat(NETQUEUE queue)
{
	BASE_OBJECT	*psObj;
	UBYTE		player,targetplayer;
	STRUCTURE	*psStruct;
	uint32_t	id,targetid;

	// TODO Add some kind of checking, so that things don't get lasatted by bunkers.
	NETbeginDecode(queue, GAME_LASSAT);
		NETuint8_t(&player);
		NETuint32_t(&id);
		NETuint32_t(&targetid);
		NETuint8_t(&targetplayer);
	NETend();

	psStruct = IdToStruct (id, player);
	psObj	 = IdToPointer(targetid, targetplayer);

	if (psStruct && psObj)
	{
		// Give enemy no quarter, unleash the lasat
		proj_SendProjectile(&psStruct->asWeaps[0], NULL, player, psObj->pos, psObj, true, 0);
		psStruct->asWeaps[0].lastFired = gameTime;

		// Play 5 second countdown message
		audio_QueueTrackPos( ID_SOUND_LAS_SAT_COUNTDOWN, psObj->pos.x, psObj->pos.y, psObj->pos.z);
	}

	return true;
}

// ////////////////////////////////////////////////////////////////////////////
// give Power
void giftPower(uint8_t from, uint8_t to, BOOL send)
{
	UDWORD gifval;
	uint32_t dummy = 0;

	if (from == ANYPLAYER)
	{
		gifval = OILDRUM_POWER;
	}
	else
	{
		// Give 1/3 of our power away
		gifval = getPower(from) / 3;
		usePower(from, gifval);
	}

	addPower(to, gifval);

	if (send)
	{
		uint8_t giftType = POWER_GIFT;

		NETbeginEncode(NET_GIFT, NET_ALL_PLAYERS);
			NETuint8_t(&giftType);
			NETuint8_t(&from);
			NETuint8_t(&to);
			NETuint32_t(&dummy);
		NETend();
	}
	else if (to == selectedPlayer)
	{
		CONPRINTF(ConsoleString,(ConsoleString,_("%s Gives You %u Power"),getPlayerName(from),gifval));
	}
}

// recv lassat info on the receiving end.
BOOL recvLasSat()
{
    BASE_OBJECT	*psObj;
    UBYTE		player,targetplayer;
    STRUCTURE	*psStruct;
    uint32_t	id,targetid;

    NETbeginDecode(NET_LASSAT);
    NETuint8_t(&player);
    NETuint32_t(&id);
    NETuint32_t(&targetid);
    NETuint8_t(&targetplayer);
    NETend();

    psStruct = IdToStruct (id, player);
    psObj	 = IdToPointer(targetid, targetplayer);

    if (psStruct && psObj)
    {
        // Give enemy no quarter, unleash the lasat
        proj_SendProjectile(&psStruct->asWeaps[0], NULL, player, psObj->pos, psObj, true, 0);

        // Play 5 second countdown message
        audio_QueueTrackPos( ID_SOUND_LAS_SAT_COUNTDOWN, psObj->pos.x, psObj->pos.y, psObj->pos.z);
    }

    return true;
}

static void giftAutoGame(uint8_t from, uint8_t to, bool send)
{
	uint32_t dummy = 0;

	if (send)
	{
		uint8_t subType = AUTOGAME_GIFT;

		NETbeginEncode(NETgameQueue(selectedPlayer), GAME_GIFT);
		NETuint8_t(&subType);
		NETuint8_t(&from);
		NETuint8_t(&to);
		NETuint32_t(&dummy);
		NETend();
		debug(LOG_SYNC, "We (%d) are telling %d we want to enable/disable a autogame", from, to);
	}
	// If we are recieving the "gift"
	else
	{
		if (to == selectedPlayer)
		{
			NetPlay.players[from].autoGame = !NetPlay.players[from].autoGame ;
			CONPRINTF(ConsoleString, (ConsoleString, "%s has %s the autoGame command", getPlayerName(from), NetPlay.players[from].autoGame ? "Enabled" : "Disabled"));
			debug(LOG_SYNC, "We (%d) are being told that %d has %s autogame", selectedPlayer, from, NetPlay.players[from].autoGame ? "Enabled" : "Disabled");
		}
	}
}

// accept and process incoming ping messages.
bool recvPing(NETQUEUE queue)
{
	bool	isNew = false;
	uint8_t	sender, us = selectedPlayer;
	uint8_t challenge[sizeof(pingChallenge)];
	EcKey::Sig challengeResponse;

	NETbeginDecode(queue, NET_PING);
	NETuint8_t(&sender);
	NETbool(&isNew);
	if (isNew)
	{
		NETbin(challenge, sizeof(pingChallenge));
	}
	else
	{
		NETbytes(&challengeResponse);
	}
	NETend();

	if (sender >= MAX_PLAYERS)
	{
		debug(LOG_ERROR, "Bad NET_PING packet, sender is %d", (int)sender);
		return false;
	}

	// If this is a new ping, respond to it
	if (isNew)
	{
		challengeResponse = getMultiStats(us).identity.sign(&challenge, sizeof(pingChallenge));

		NETbeginEncode(NETnetQueue(sender), NET_PING);
		// We are responding to a new ping
		isNew = false;

		NETuint8_t(&us);
		NETbool(&isNew);
		NETbytes(&challengeResponse);
		NETend();
	}
	// They are responding to one of our pings
	else
	{
		if (!getMultiStats(sender).identity.empty() && !getMultiStats(sender).identity.verify(challengeResponse, pingChallenge, sizeof(pingChallenge)))
		{
			// Either bad signature, or we sent more than one ping packet and this response is to an older one than the latest.
			debug(LOG_NEVER, "Bad and/or old NET_PING packet, alleged sender is %d", (int)sender);
			return false;
		}

		// Work out how long it took them to respond
		ingame.PingTimes[sender] = (realTime - PingSend[sender]) / 2;

		// Note that we have received it
		PingSend[sender] = 0;
	}

	return true;
}

// sendGiftDroids()
// We give selected droid(s) as a gift to another player.
//
// \param from  :player that sent us the droid
// \param to    :player that should be getting the droid
static void sendGiftDroids(uint8_t from, uint8_t to)
{
	DROID        *next, *psD;
	uint8_t      giftType = DROID_GIFT;
	uint8_t      totalToSend;

	if (apsDroidLists[from] == NULL)
	{
		return;
	}

	/*
	 * Work out the number of droids to send. As well as making sure they are
	 * selected we also need to make sure they will NOT put the receiving player
	 * over their droid limit.
	 */

	for (totalToSend = 0, psD = apsDroidLists[from];
	     psD && getNumDroids(to) + totalToSend < getMaxDroids(to) && totalToSend != UINT8_MAX;
	     psD = psD->psNext)
	{
		if (psD->selected)
				++totalToSend;
	}
	/*
	 * We must send one droid at a time, due to the fact that giftSingleDroid()
	 * does its own net calls.
	 */

	for (psD = apsDroidLists[from]; psD && totalToSend != 0; psD = next)
	{
		// Store the next droid in the list as the list may change
		next = psD->psNext;

		if (psD->droidType == DROID_TRANSPORTER
		 && !transporterIsEmpty(psD))
		{
			CONPRINTF(ConsoleString, (ConsoleString, _("Tried to give away a non-empty %s - but this is not allowed."), psD->aName));
			continue;
		}
		if (psD->selected)
		{
			NETbeginEncode(NET_GIFT, NET_ALL_PLAYERS);
			NETuint8_t(&giftType);
			NETuint8_t(&from);
			NETuint8_t(&to);
			// Add the droid to the packet
			NETuint32_t(&psD->id);
			NETend();

			// Hand over the droid on our sidde
			giftSingleDroid(psD, to);

			// Decrement the number of droids left to send
			--totalToSend;
		}
	}
}

void sendAlliance(uint8_t from, uint8_t to, uint8_t state, int32_t value)
{
	NETbeginEncode(NET_ALLIANCE, NET_ALL_PLAYERS);
		NETuint8_t(&from);
		NETuint8_t(&to);
		NETuint8_t(&state);
		NETint32_t(&value);
	NETend();
}

void sendAlliance(uint8_t from, uint8_t to, uint8_t state, int32_t value)
{
	NETbeginEncode(NETgameQueue(selectedPlayer), GAME_ALLIANCE);
	NETuint8_t(&from);
	NETuint8_t(&to);
	NETuint8_t(&state);
	NETint32_t(&value);
	NETend();
}

// ///////////////////////////////////////////////////////////////
// receive splattered artifacts
void recvMultiPlayerRandomArtifacts(NETQUEUE queue)
{
	int				count, i;
	uint8_t			quantity, player;
	uint32_t		tx,ty;
	uint32_t		ref;
	FEATURE_TYPE            type = FEAT_TREE;  // Dummy initialisation.
	FEATURE 		*pF;

	NETbeginDecode(queue, GAME_ARTIFACTS);
		NETuint8_t(&quantity);
		NETenum(&type);

	debug(LOG_FEATURE, "receiving %u artifact(s) type: (%s)", quantity, feature_names[type]);
	for (i = 0; i < numFeatureStats && asFeatureStats[i].subType != type; i++) {}

	for (count = 0; count < quantity; count++)
	{
		MAPTILE *psTile;

		NETuint32_t(&tx);
		NETuint32_t(&ty);
		NETuint32_t(&ref);
		NETuint8_t(&player);

		if (tx == INVALID_XY)
		{
			continue;
		}
		else if (!tileOnMap(tx, ty))
		{
			debug(LOG_ERROR, "Bad tile coordinates (%u,%u)", tx, ty);
			continue;
		}
		psTile = mapTile(tx, ty);
		if (!psTile || psTile->psObject != NULL)
		{
			debug(LOG_ERROR, "Already something at (%u,%u)!", tx, ty);
			continue;
		}

		pF = buildFeature((asFeatureStats + i), world_coord(tx), world_coord(ty), false);
		if (pF)
		{
			pF->id		= ref;
			pF->player	= player;
			syncDebugFeature(pF, '+');
		}
		else
		{
			debug(LOG_ERROR, "Couldn't build feature %u for player %u ?", ref, player);
		}
	}
	NETend();
}

// ////////////////////////////////////////////////////////////////////////////
// Send a new Droid to the other players
bool SendDroid(DROID_TEMPLATE *pTemplate, uint32_t x, uint32_t y, uint8_t player, uint32_t id, const INITIAL_DROID_ORDERS *initialOrdersP)
{
	if (!bMultiMessages)
	{
		return true;
	}

	ASSERT_OR_RETURN(false, x != 0 && y != 0, "SendDroid: Invalid droid coordinates");
	ASSERT_OR_RETURN(false, player < MAX_PLAYERS, "invalid player %u", player);

	// Dont send other droids during campaign setup
	if (ingame.localJoiningInProgress)
	{
		return true;
	}

	// Only send the droid if we are responsible
	if (!myResponsibility(player))
	{
		// Don't build if we are not responsible
		return false;
	}

	debug(LOG_SYNC, "Droid sent with id of %u", id);
	NETbeginEncode(NETgameQueue(selectedPlayer), GAME_DEBUG_ADD_DROID);
	{
		Position pos(x, y, 0);
		bool haveInitialOrders = initialOrdersP != NULL;
		int32_t droidType = pTemplate->droidType;

		NETuint8_t(&player);
		NETuint32_t(&id);
		NETPosition(&pos);
		NETqstring(pTemplate->name);
		NETint32_t(&droidType);
		NETuint8_t(&pTemplate->asParts[COMP_BODY]);
		NETuint8_t(&pTemplate->asParts[COMP_BRAIN]);
		NETuint8_t(&pTemplate->asParts[COMP_PROPULSION]);
		NETuint8_t(&pTemplate->asParts[COMP_REPAIRUNIT]);
		NETuint8_t(&pTemplate->asParts[COMP_ECM]);
		NETuint8_t(&pTemplate->asParts[COMP_SENSOR]);
		NETuint8_t(&pTemplate->asParts[COMP_CONSTRUCT]);
		NETint8_t(&pTemplate->numWeaps);
		for (int i = 0; i < pTemplate->numWeaps; i++)
		{
			NETuint8_t(&pTemplate->asWeaps[i]);
		}
		NETbool(&haveInitialOrders);
		if (haveInitialOrders)
		{
			INITIAL_DROID_ORDERS initialOrders = *initialOrdersP;
			NETuint32_t(&initialOrders.secondaryOrder);
			NETint32_t(&initialOrders.moveToX);
			NETint32_t(&initialOrders.moveToY);
			NETuint32_t(&initialOrders.factoryId);  // For making scripts happy.
		}
	}
	debug(LOG_LIFE, "===> sending Droid from %u id of %u ", player, id);
	return NETend();
}

BOOL sendLasSat(UBYTE player, STRUCTURE *psStruct, BASE_OBJECT *psObj)
{
	NETbeginEncode(NETgameQueue(selectedPlayer), GAME_LASSAT);

		NETuint8_t(&player);
		NETuint32_t(&psStruct->id);
		NETuint32_t(&psObj->id);	// Target
		NETuint8_t(&psObj->player);	// Target player

	return NETend();
}

// sendGiftDroids()
// We give selected droid(s) as a gift to another player.
//
// \param from  :player that sent us the droid
// \param to    :player that should be getting the droid
static void sendGiftDroids(uint8_t from, uint8_t to)
{
	DROID        *psD;
	uint8_t      giftType = DROID_GIFT;
	uint8_t      totalToSend;

	if (apsDroidLists[from] == nullptr)
	{
		return;
	}

	/*
	 * Work out the number of droids to send. As well as making sure they are
	 * selected we also need to make sure they will NOT put the receiving player
	 * over their droid limit.
	 */

	for (totalToSend = 0, psD = apsDroidLists[from];
	     psD && getNumDroids(to) + totalToSend < getMaxDroids(to) && totalToSend != UINT8_MAX;
	     psD = psD->psNext)
	{
		if (psD->selected)
		{
			++totalToSend;
		}
	}
	/*
	 * We must send one droid at a time, due to the fact that giftSingleDroid()
	 * does its own net calls.
	 */

	for (psD = apsDroidLists[from]; psD && totalToSend != 0; psD = psD->psNext)
	{
		if (isTransporter(psD)
		    && !transporterIsEmpty(psD))
		{
			CONPRINTF(ConsoleString, (ConsoleString, _("Tried to give away a non-empty %s - but this is not allowed."), psD->aName));
			continue;
		}
		if (psD->selected)
		{
			NETbeginEncode(NETgameQueue(selectedPlayer), GAME_GIFT);
			NETuint8_t(&giftType);
			NETuint8_t(&from);
			NETuint8_t(&to);
			// Add the droid to the packet
			NETuint32_t(&psD->id);
			NETend();

			// Decrement the number of droids left to send
			--totalToSend;
		}
	}
}

BOOL sendLasSat(UBYTE player, STRUCTURE *psStruct, BASE_OBJECT *psObj)
{
    NETbeginEncode(NET_LASSAT, NET_ALL_PLAYERS);

    NETuint8_t(&player);
    NETuint32_t(&psStruct->id);
    NETuint32_t(&psObj->id);	// Target
    NETuint8_t(&psObj->player);	// Target player

    return NETend();
}

// ////////////////////////////////////////////////////////////////////////////
// add an artifact on destruction if required.
void  technologyGiveAway(const STRUCTURE *pS)
{
	int				i;
	uint8_t			count = 1;
	uint32_t		x, y;
	FEATURE			*pF = NULL;
	FEATURE_TYPE	type = FEAT_GEN_ARTE;

	// If a fully built factory (or with modules under construction) which is our responsibility got destroyed
	if (pS->pStructureType->type == REF_FACTORY && (pS->status == SS_BUILT || pS->currentBuildPts >= pS->body)
	 && myResponsibility(pS->player))
	{
		x = map_coord(pS->pos.x);
		y = map_coord(pS->pos.y);

		// Pick a tile to place the artifact
		if (!pickATileGen(&x, &y, LOOK_FOR_EMPTY_TILE, zonedPAT))
		{
			ASSERT(false, "technologyGiveAway: Unable to find a free location");
		}

		// Get the feature offset
		for(i = 0; i < numFeatureStats && asFeatureStats[i].subType != FEAT_GEN_ARTE; i++);

		// 'Build' the artifact
		pF = buildFeature((asFeatureStats + i), world_coord(x), world_coord(y), false);
		if (pF)
		{
			pF->player = pS->player;
		}

		NETbeginEncode(NET_ARTIFACTS, NET_ALL_PLAYERS);
		{
			/* Make sure that we don't have to violate the constness of pS.
			 * Since the nettype functions aren't const correct when sending
			 */
			uint8_t player = pS->player;

			NETuint8_t(&count);
			NETenum(&type);
			NETuint32_t(&x);
			NETuint32_t(&y);
			NETuint32_t(&pF->id);
			NETuint8_t(&player);
		}
		NETend();
	}

	return;
}

// recv lassat info on the receiving end.
bool recvLasSat(NETQUEUE queue)
{
	BASE_OBJECT	*psObj;
	UBYTE		player, targetplayer;
	STRUCTURE	*psStruct;
	uint32_t	id, targetid;

	NETbeginDecode(queue, GAME_LASSAT);
	NETuint8_t(&player);
	NETuint32_t(&id);
	NETuint32_t(&targetid);
	NETuint8_t(&targetplayer);
	NETend();

	psStruct = IdToStruct(id, player);
	psObj	 = IdToPointer(targetid, targetplayer);
	if (psStruct && !canGiveOrdersFor(queue.index, psStruct->player))
	{
		syncDebug("Wrong player.");
		return false;
	}

	if (psStruct && psObj && psStruct->pStructureType->psWeapStat[0]->weaponSubClass == WSC_LAS_SAT)
	{
		// Lassats have just one weapon
		unsigned firePause = weaponFirePause(&asWeaponStats[psStruct->asWeaps[0].nStat], player);
		unsigned damLevel = PERCENT(psStruct->body, structureBody(psStruct));

		if (damLevel < HEAVY_DAMAGE_LEVEL)
		{
			firePause += firePause;
		}

		if (isHumanPlayer(player) && gameTime - psStruct->asWeaps[0].lastFired <= firePause)
		{
			/* Too soon to fire again */
			return true ^ false;  // Return value meaningless and ignored.
		}

		// Give enemy no quarter, unleash the lasat
		proj_SendProjectile(&psStruct->asWeaps[0], NULL, player, psObj->pos, psObj, true, 0);
		psStruct->asWeaps[0].lastFired = gameTime;
		psStruct->asWeaps[0].ammo = 1; // abducting this field for keeping track of triggers

		// Play 5 second countdown message
		audio_QueueTrackPos(ID_SOUND_LAS_SAT_COUNTDOWN, psObj->pos.x, psObj->pos.y, psObj->pos.z);
	}

	return true;
}

/// Does not read/write info->droidId!
static void NETQueuedDroidInfo(QueuedDroidInfo *info)
{
	NETuint8_t(&info->player);
	NETenum(&info->order);
	NETbool(&info->subType);
	if (info->subType)
	{
		NETuint32_t(&info->destId);
		NETenum(&info->destType);
	}
	else
	{
		NETuint32_t(&info->x);
		NETuint32_t(&info->y);
	}
	if (info->order == DORDER_BUILD || info->order == DORDER_LINEBUILD)
	{
		NETuint32_t(&info->structRef);
		NETuint16_t(&info->direction);
	}
	if (info->order == DORDER_LINEBUILD)
	{
		NETuint32_t(&info->x2);
		NETuint32_t(&info->y2);
	}
}