//----------------------------------------------------------
// pet_ping.script
// -----------------------------------------------------------------------
// This script is a re-hash of vehicle_ping.script, altered to function for pets
// Original script notes listed below.
//
// This script is attached to a vehicle.  It is setup to
// send a ping to the vehicle's vehicle control device (PCD).
// If the PCD does not respond to the ping in a timely fashion
// or it responds with an indication that this vehicle is not
// supposed to be out, the vehicle is destroyed.  A positive
// acknowledgement from the PCD is required for the vehicle
// to continue to exist in the world.
//----------------------------------------------------------

include library.callable;
include library.pet_lib;
include library.utils;

//----------------------------------------------------------

const string PCDPING_PCD_SCRIPT_NAME         = "ai.pcd_ping_response";

const string PCDPING_SEND_MESSAGE_NUMBER     = "pcdping.sendMsgNumber";
const string PCDPING_LAST_ACK_MESSAGE_NUMBER = "pcdping.lastAckNumber";

const string PCDPING_MESSAGE_PET_ID_NAME = "petId";
const string PCDPING_MESSAGE_MESSAGE_ID_NAME = "messageId";
const string PCDPING_MESSAGE_RIDER_ID_NAME   = "riderId";

const string PCDPING_PING_CALLBACK_NAME      = "petPingCallback";
const string PCDPING_PCD_MESSAGEHANDLER_NAME = "handlePetPing";

const int    PCDPING_MAX_UNACKNOWLEDGED_MESSAGE_COUNT = 3;
const int    PCDPING_PING_INTERVAL_INITIAL            = 1;
const int    PCDPING_PING_INTERVAL_STANDARD           = 300;
const int    PCDPING_PING_INTERVAL_RETRY              = 30;

const boolean debug = false;

//----------------------------------------------------------

trigger OnAttach()
{
	if (debug)
		LOG("pcdping-debug", "pet_ping.OnAttach(): self = [" + self + "] entered");

	//-- Initialize pcd ping variables.
	// Note: these objvars are not expensive because pets are not persisted.
	setObjVar(self, PCDPING_SEND_MESSAGE_NUMBER, 0);
	setObjVar(self, PCDPING_LAST_ACK_MESSAGE_NUMBER, 0);

	//-- Kick off the first ping heartbeat now.
	messageTo(self, PCDPING_PING_CALLBACK_NAME, null, PCDPING_PING_INTERVAL_INITIAL, false);

	if (debug)
		LOG("pcdping-debug", "pet_ping.OnAttach(): self = [" + self + "] exited");

	return SCRIPT_CONTINUE;
}

//----------------------------------------------------------
/**
 * This is the heartbeat callback function for the pet/pcd ping system.
 */

messageHandler petPingCallback()
{
	if (debug)
		LOG("pcdping-debug", "pet_ping.petPingCallback(): self = [" + self + "] entered");


	obj_id player = getRiderId(self);
	if(!isValidId(player) && pet_lib.isMount(self))
	{
		pet_lib.storePet(self);
		return SCRIPT_CONTINUE;
	}
	
	//-- Setup the new pet ping message number.  These get incremented by 1 each ping callback.
	const int previousMessageNumber = getIntObjVar(self, PCDPING_SEND_MESSAGE_NUMBER);
	const int newMessageNumber = previousMessageNumber + 1;
	setObjVar(self, PCDPING_SEND_MESSAGE_NUMBER, newMessageNumber);

	//-- If previousMessageNumber == 0, this means we're just starting.
	if (previousMessageNumber == 0)
		ensurePcdHasSisterScript(self);

	//-- Retrieve the last PCD-acknowledged message number.
	const int mostRecentAcknowledgedMessageNumber = getIntObjVar(self, PCDPING_LAST_ACK_MESSAGE_NUMBER);

	//-- Check if we've exceeded the maximum number of unacknowledged
	const int unacknowledgedGap = previousMessageNumber - mostRecentAcknowledgedMessageNumber;
	if (unacknowledgedGap > PCDPING_MAX_UNACKNOWLEDGED_MESSAGE_COUNT)
	{
		boolean killSuccess = doPingBasedKill(self, "pet received no acknowledgement from PCD, killing pet with unacknowleged gap=[" + unacknowledgedGap + "]. PCD appears to be unloaded.");
		if (killSuccess)
			return SCRIPT_CONTINUE;
		else
		{
			LOG("mounts-bug", "pet_ping.petPingCallback(): doPingBasedKill() failed for pet=[" + self + "], continuing ping loop so that we can try to kill it later.");
			// continue through here so we requeue the callback for another attempt (or possible recovery) later.
		}
	}

	//-- Determine next callback interval based on whether our most recent send was acknowledged.
	//   If our most recent send has been acknowledged, use the infrequent, standard time interval
	//   for this callback.  Otherwise accelerate the ping so we get rid of this suspect pet
	//   more rapidly.
	const int nextCallbackInterval = (unacknowledgedGap <= 0) ? PCDPING_PING_INTERVAL_STANDARD : PCDPING_PING_INTERVAL_RETRY;

	//-- Setup ping message to the pet control device.
	// Get the PCD id.
	obj_id controlDevice = callable.getCallableCD(self);
	
	const boolean hasValidPcd = isIdValid(controlDevice);

	if (!hasValidPcd)
	{
		boolean killSuccess = doPingBasedKill(self, "pet does not have a valid PCD objvar");
		if (killSuccess)
			return SCRIPT_CONTINUE;
		else
		{
			LOG("mounts-bug", "pet_ping.petPingCallback(): doPingBasedKill() failed for pet=[" + self + "], continuing ping loop so that we can try to kill it later.");
			// continue through here so we requeue the callback for another attempt (or possible recovery) later.
		}
	}
	else
	{
		// Construct the dictionary of info about this pet that we'll pass to the PCD.
		dictionary messageData = new dictionary();

		messageData.put(PCDPING_MESSAGE_PET_ID_NAME, self);
		messageData.put(PCDPING_MESSAGE_MESSAGE_ID_NAME, newMessageNumber);

		// If this pet has a rider, include the rider id.
		obj_id riderId = getRiderId(self);
		if (isIdValid(riderId))
			messageData.put(PCDPING_MESSAGE_RIDER_ID_NAME, riderId);

		// Send the ping message to the PCD, get it there as fast as possible.
		messageTo(controlDevice, PCDPING_PCD_MESSAGEHANDLER_NAME, messageData, 1, false);

		if (debug)
			LOG("pcdping-debug", "pet_ping.petPingCallback(): self = [" + self + "] sent ping message to PCD.");
	}


	//-- Enqueue next pet ping callback.
	messageTo(self, PCDPING_PING_CALLBACK_NAME, null, nextCallbackInterval, false);

	if (debug)
		LOG("pcdping-debug", "pet_ping.petPingCallback(): self = [" + self + "] exited");

	return SCRIPT_CONTINUE;
}

//----------------------------------------------------------
/**
 * This message is sent by the PCD and received by the pet
 * when the PCD is in agreement that this pet should be out.
 */

messageHandler handlePositiveAcknowledgementFromPcd()
{
	if (debug)
		LOG("pcdping-debug", "pet_ping.handlePositiveAcknowledgementFromPcd(): self = [" + self + "] entered");

	//-- Extract the acknowledgement message number from the message data.
	const int ackMessageNumber = params.getInt(PCDPING_MESSAGE_MESSAGE_ID_NAME);

	//-- Retrieve the last acknowledged message number for the pet.
	const int mostRecentAckMessageNumber = getIntObjVar(self, PCDPING_LAST_ACK_MESSAGE_NUMBER);

	//-- Apply message ack number if it is larger than the largest ack number we've seen so far.
	if (ackMessageNumber > mostRecentAckMessageNumber)
	{
		// This message is an ack to a newer message number than the previous highest ack.  Store it.
		setObjVar(self, PCDPING_LAST_ACK_MESSAGE_NUMBER, ackMessageNumber);

		if (debug)
			LOG("pcdping-debug", "pet_ping.handlePositiveAcknowledgementFromPcd(): processed newer positive PCD ack number=[" + ackMessageNumber + "]");
	}
	else
	{
		// Skip this ack --- it's an ack for an older message when we've already received a newer one.
		if (debug)
			LOG("pcdping-debug", "pet_ping.handlePositiveAcknowledgementFromPcd(): discarded older positive PCD ack number=[" + ackMessageNumber + "], highest ack is [" + mostRecentAckMessageNumber + "]");
	}

	if (debug)
		LOG("pcdping-debug", "pet_ping.handlePositiveAcknowledgementFromPcd(): self = [" + self + "] exited");

	return SCRIPT_CONTINUE;
}

//----------------------------------------------------------
/**
 * This message is sent by the PCD and received by the pet
 * when the PCD does not believe this pet should be out.
 */

messageHandler handleNegativeAcknowledgementFromPcd()
{
	if (debug)
		LOG("pcdping-debug", "pet_ping.handleNegativeAcknowledgementFromPcd(): self = [" + self + "] entered");

	//-- Destroy the pet now.
	const boolean killSuccess = doPingBasedKill(self, "PCD indicated that this pet should not exist");
	if (debug)
		LOG("pcdping-debug", "pet_ping.handleNegativeAcknowledgementFromPcd(): self = [" + self + "] attempted to kill pet per PCD request.  killSuccess=[" + killSuccess + "]");

	if (debug)
		LOG("pcdping-debug", "pet_ping.handleNegativeAcknowledgementFromPcd(): self = [" + self + "] exited");

	return SCRIPT_CONTINUE;
}

//----------------------------------------------------------

boolean doPingBasedKill(obj_id pet, string reason)
{
	if(debug)
		LOG("pcdping-debug", "pet_ping.doPingBasedKill(): pet = [" + pet + "] entered");

	//-- Log the ping-based kill.
	LOG("pcdping-kill", "Killing pet id=[" + pet + "]: reason=[" + reason + "]");

	//-- Destroy the pet.

	// Dismount the rider of this mount/pet if there's anything on it.
	obj_id rider = getRiderId(pet);

	if(isIdValid(rider))
	{
		// Do the dismount immediately.
		boolean dismountSuccess = pet_lib.doDismountNow(rider);

		if(!dismountSuccess)
		{
			LOG("mounts-bug", "pet_ping.doPingBasedKill(): creature [" + pet + "], rider [" + rider + "] failed to dismount.  Will still try to kill the pet.");
		}
	}

	// Destroy the pet.
	obj_id petControlDevice = callable.getCallableCD(pet);
	pet_lib.savePetInfo(pet, petControlDevice);
	utils.setScriptVar(pet, "stored", true);

	boolean killSuccess = destroyObject(pet);

	if(!killSuccess)
	{
		LOG("pcdping-kill", "failed to destroy pet=[" + pet + "].");
	}

	if(debug)
	{
		LOG("pcdping-debug", "pet_ping.doPingBasedKill(): pet = [" + pet + "] exited");
	}

	return killSuccess;
}

//----------------------------------------------------------

void ensurePcdHasSisterScript(obj_id pet)
{
	//-- Double check that the PCD for this pet has the PCD sister script attached.
	// @todo might as well handle this here and remove the one that attaches the script
	// to the PCD via the pet_control_device.script's OnInitialize() trigger.

	// Get the pet control device.
	obj_id controlDevice = callable.getCallableCD(pet);

	// Ensure that the PCD has the pet ping response script attached.
	if(isIdValid(controlDevice) && !hasScript(controlDevice, PCDPING_PCD_SCRIPT_NAME))
	{
		if (debug)
		{
			LOG("pcdping-debug", "pet_ping.ensurePcdHasSisterScript(): attaching script [" + PCDPING_PCD_SCRIPT_NAME + "] to PCD id=[" + controlDevice + "]");
		}

		attachScript(controlDevice, PCDPING_PCD_SCRIPT_NAME);
	}
	else
	{
		if (debug)
		{
			LOG("pcdping-debug", "pet_ping.ensurePcdHasSisterScript(): couldn't attach script [" + PCDPING_PCD_SCRIPT_NAME + "] to PCD because didn't have objvar");
		}
	}

}

//----------------------------------------------------------