//===========================================================================//
// File:	messmgr.cpp                                                         //
// Project: BattleTech           Brick: Mech subsystems                       //
// Contents: SubsystemMessageManager -- the per-mech damage/explosion hub     //
//---------------------------------------------------------------------------//
// Copyright (C) 1995, Virtual World Entertainment, Inc.                     //
// All Rights reserved worldwide                                             //
// This unpublished sourcecode is PROPRIETARY and CONFIDENTIAL               //
//===========================================================================//

#include <bt.hpp>
#pragma hdrstop

#if !defined(MESSMGR_HPP)
#	include <messmgr.hpp>
#endif

#if !defined(MECH_HPP)
#	include <mech.hpp>
#endif

#if !defined(MECHWEAP_HPP)
#	include <mechweap.hpp>		// ExplosionResourceIDOf (weapon @0x3e4)
#endif

#if !defined(EXPLODE_HPP)
#	include <explode.hpp>		// Explosion::MakeMessage
#endif

#if !defined(APP_HPP)
#	include <app.hpp>			// application->Post / GetRegistry / priorities
#endif

#if !defined(REGISTRY_HPP)
#	include <registry.hpp>		// complete Registry type for the Post upcast
#endif

Derivation
	SubsystemMessageManager::ClassDerivations(
		Subsystem::ClassDerivations,
		"SubsystemMessageManager"
	);

SubsystemMessageManager::SharedData
	SubsystemMessageManager::DefaultData(
		SubsystemMessageManager::ClassDerivations,
		Subsystem::MessageHandlers,
		Subsystem::AttributeIndex,
		Subsystem::StateCount
	);

SubsystemMessageManager::SubsystemMessageManager(
	Mech				*owner,
	int					subsystem_ID,
	SubsystemResource	*sub_res,
	SharedData			&shared_data
):
	Subsystem(owner, subsystem_ID, sub_res, shared_data),
	weaponExplosions(NULL, True),		// @0049bca4: chain ctor (0, 1) --
										// UNIQUE-keyed (one plug per explosion
										// resource; the consolidator also
										// Find()s before adding)
	damageInformation(NULL, False)		// (0, 0) -- duplicate keys allowed
{
	Check(owner);
	Check_Pointer(sub_res);

	//
	// [T3] The binary ctor also allocates a 0x160-byte engine-internal
	// helper object at this+0xE0 (FUN_0041de1c(obj, this, 0); released in
	// the dtor by virtual op 3).  It is not declared in the surviving
	// MESSMGR.HPP and nothing in the reconstructed damage path touches it;
	// STAGED until its class is identified.
	//

	//
	// The per-frame Performance (binary @0049bca4 copies the member-pointer
	// triple @0050b6fc..0050b704 == &ConsolidateAndSendDamage).
	//
	SetPerformance(&SubsystemMessageManager::ConsolidateAndSendDamage);

	//
	// The two streamed resource fields (res+0x30 / res+0x34).
	//
	terrainHitExplosionID	= sub_res->terrainHitExplosionID;
	rendererCompensateTime	= sub_res->rendererCompensateTime;

	//
	// The common-damage record starts empty (first hit of a frame fills it).
	//
	commonDamageInformation.entityHit		= NULL;
	commonDamageInformation.damageZoneIndex	= -1;
	commonDamageInformation.impactPoint		= Point3D::Identity;

	Check_Fpu();
}

SubsystemMessageManager::~SubsystemMessageManager()
{
}

Logical
	SubsystemMessageManager::TestInstance() const
{
	return IsDerivedFrom(ClassDerivations);
}

//
//#############################################################################
// AddDamageMessage -- binary @0049b6d8 (172 bytes), verified against the raw
// decomp (part_012.c).
//
// Called by the damage paths while a frame runs: the FIRST hit of the frame
// wins each field of the common record (entity, impact point, zone), and
// every message queues a DamageInformation plug into the damage chain KEYED
// BY ITS DAMAGE AMOUNT (the chain key is the Scalar the consolidator later
// reads back with GetValue()).
//#############################################################################
//
void
	SubsystemMessageManager::AddDamageMessage(
		Entity						*damaged_entity,
		Entity__TakeDamageMessage	*message
	)
{
	Check(this);
	Check(damaged_entity);
	Check_Pointer(message);

	if (commonDamageInformation.entityHit == NULL)
	{
		commonDamageInformation.entityHit = damaged_entity;
	}

	//
	// The binary's origin test is an epsilon compare against the zero point
	// (FUN_004084fc(point, origin, 0.0001)).
	//
	if (Close_Enough(commonDamageInformation.impactPoint, Point3D::Identity, 0.0001f))
	{
		commonDamageInformation.impactPoint = message->damageData.impactPoint;
	}

	if (commonDamageInformation.damageZoneIndex == -1)
	{
		commonDamageInformation.damageZoneIndex = message->damageZone;
	}

	DamageInformation
		*info = new DamageInformation;
	Register_Object(info);
	info->damageType	= message->damageData.damageType;
	info->subsystemID	= message->inflictingSubsystemID;

	damageInformation.AddValue(info, message->damageData.damageAmount);
}

//
//#############################################################################
// ConsolidateAndSendDamage -- binary @0049b784 (796 bytes), the per-frame
// Performance, verified against the raw decomp.
//
// If any damage queued this frame: build ONE TakeDamageStreamMessage for the
// common hit entity (impact point, zone, shooter = the owning mech), append
// {count, [damageType, damageAmount, subsystemID]...} through a dynamic
// message -- the wire format is fixed by the ENGINE'S OWN PARSER
// (Entity::TakeDamageStreamMessageHandler, entity.cpp: count first, then the
// triple per record) -- bundle each firing weapon's explosion resource into
// the explosion queue (dedup'd), Dispatch the stream at the hit entity, and
// flush the queued explosions.  Always: purge the damage chain and reset the
// common record for the next frame.
//#############################################################################
//
void
	SubsystemMessageManager::ConsolidateAndSendDamage(Scalar)
{
	Check(this);

	Mech
		*owner = GetEntity();
	Check(owner);

	VChainIteratorOf<DamageInformation*, Scalar>
		damageWalk(&damageInformation);

	damageWalk.First();
	if (damageWalk.GetCurrent() != NULL)
	{
		//
		// The engine parser reads the record count first, so count the
		// chain up front.
		//
		int
			entry_count = 0;
		for (damageWalk.First(); damageWalk.GetCurrent() != NULL; damageWalk.Next())
		{
			++entry_count;
		}

		//
		// The consolidated stream (binary: Receiver__DynamicMessage ctor
		// FUN_00419e18(TakeDamageStreamMessageID == 0x13, sizeof == 0x34),
		// header fields written in place at +0x1c/+0x28/+0x2c).
		//
		Receiver::DynamicMessage
			stream_message(
				Entity::TakeDamageStreamMessageID,
				sizeof(Entity::TakeDamageStreamMessage)
			);
		{
			Entity::TakeDamageStreamMessage
				*header =
					(Entity::TakeDamageStreamMessage *)
						stream_message.GetMessagePointer();
			header->impactPoint		= commonDamageInformation.impactPoint;
			header->damageZoneIndex	= commonDamageInformation.damageZoneIndex;
			header->shootingEntity	= owner->GetEntityID();
		}

		stream_message << entry_count;

		for (damageWalk.First(); damageWalk.GetCurrent() != NULL; damageWalk.Next())
		{
			DamageInformation
				*info = damageWalk.GetCurrent();

			stream_message
				<< (int)info->damageType
				<< (Scalar)damageWalk.GetValue()
				<< (int)info->subsystemID;

			//
			// Bundle the FIRING weapon's explosion (binary: blind read of
			// roster[subsystemID]+0x3e4).  [T1] The binary neither range-
			// checks the id nor verifies the subsystem is a weapon; damage
			// with an unthreaded id (-1) or a non-weapon inflicter would
			// read garbage there.  Guarded here -- a guarded miss queues
			// nothing, which is also what a Null resource does.
			//
			Subsystem
				*firing = NULL;
			if (
				info->subsystemID >= 0 &&
				info->subsystemID < owner->GetSubsystemCount()
			)
			{
				firing = owner->GetSubsystem(info->subsystemID);
			}
			if (
				firing != NULL &&
				firing->IsDerivedFrom(MechWeapon::ClassDerivations)
			)
			{
				ResourceDescription::ResourceID
					explosion_ID =
						((MechWeapon *)firing)->ExplosionResourceIDOf();
				if (
					explosion_ID != ResourceDescription::NullResourceID &&
					weaponExplosions.Find(explosion_ID) == NULL
				)
				{
					ResourceIDPlug
						*plug = new ResourceIDPlug(explosion_ID);
					Register_Object(plug);
					weaponExplosions.AddValue(plug, explosion_ID);
				}
			}
		}

		//
		// [T3] The binary computes a terrain-hit flag here:
		// entityHit->IsDerivedFrom(<Derivation @0x4e6f54>).  The class at
		// that BSS address is UNRESOLVED (no static-ctor reference survives
		// in the decomp parts) -- but the flag is PROVABLY INERT:
		// CreateWeaponExplosions (@0049baa0) never reads its first
		// argument, and terrainHitExplosionID is never consumed anywhere in
		// the shipped cluster.  A declared, resourced, and abandoned 1995
		// feature; False preserves shipped behavior exactly.
		//
		Logical
			terrain_hit = False;

		if (commonDamageInformation.entityHit != NULL)
		{
			CreateWeaponExplosions(
				terrain_hit,
				commonDamageInformation.entityHit->GetEntityID(),
				commonDamageInformation.impactPoint
			);
			commonDamageInformation.entityHit->Dispatch(
				stream_message.GetMessagePointer());
		}
	}

	//
	// Teardown every frame (binary FUN_00417858(iter, 1)): unregister and
	// delete the consumed plugs, then reset the common record.
	//
	damageWalk.First();
	damageWalk.DeletePlugs();

	commonDamageInformation.entityHit		= NULL;
	commonDamageInformation.damageZoneIndex	= -1;
	commonDamageInformation.impactPoint		= Point3D::Identity;

	Check_Fpu();
}

//
//#############################################################################
// CreateWeaponExplosions -- binary @0049baa0 (516 bytes), verified against
// the raw decomp.  The authentic signature is the surviving MESSMGR.HPP's;
// note terrain_hit is never read by the shipped body (see the [T3] note in
// the consolidator).
//
// Flush the queued explosion resources: for each, post an
// Explosion::MakeMessage at the Registry -- the byte-for-byte template from
// the binary: MakeMessageID (3), sizeof 0x5c, ExplosionClassID (0x31 -- the
// VDATA enum ordinal matches the binary exactly), no owner, the queued
// resource, instance flags 0x100, an identity-rotation Origin at the impact
// point, the hit entity, and the owning mech as creator.  Deliveries stagger
// 0.1s apart (the first at now+0.1) so several impacts in one frame read as
// separate blasts.  Then purge the queue.
//#############################################################################
//
void
	SubsystemMessageManager::CreateWeaponExplosions(
		Logical		/*terrain_hit*/,
		EntityID	entity_hit,
		Point3D		explode_position
	)
{
	Check(this);

	Mech
		*owner = GetEntity();
	Check(owner);

	VChainIteratorOf<ResourceIDPlug*, ResourceDescription::ResourceID>
		explosionWalk(&weaponExplosions);

	Origin
		explosion_origin(Origin::Identity);
	explosion_origin.linearPosition = explode_position;

	Scalar
		time_step = 0.0f;

	for (
		explosionWalk.First();
		explosionWalk.GetCurrent() != NULL;
		explosionWalk.Next()
	)
	{
		ResourceDescription::ResourceID
			explosion_ID = explosionWalk.GetValue();

		time_step += 0.1f;
		Time
			when = Now();
		when += time_step;

		Explosion::MakeMessage
			make_message(
				Entity::MakeMessageID,
				sizeof(Explosion::MakeMessage),
				RegisteredClass::ExplosionClassID,
				EntityID(),
				explosion_ID,
				0x100,
				explosion_origin,
				entity_hit,
				owner->GetEntityID()
			);

		Check(application);
		application->Post(
			CreationEventPriority,
			application->GetRegistry(),
			&make_message,
			when
		);
	}

	explosionWalk.First();
	explosionWalk.DeletePlugs();

	Check_Fpu();
}


//
//#############################################################################
// CreateStreamedSubsystem -- binary @0049be10 (324 bytes).  Chains the base
// Subsystem record, stamps classID 0x0BD3 / size 0x38, resolves the
// REQUIRED "TerrainHitExplosion" model family, reads the REQUIRED
// "RendererCompensateTime".  (The runtime never consumes either field --
// see the inert terrain-hit note above -- but the authored stream carries
// both, so the converter writes both.)
//#############################################################################
//
Logical
	SubsystemMessageManager::CreateStreamedSubsystem(
		ResourceFile				*resource_file,
		NotationFile				*model_file,
		const char					*model_name,
		const char					*subsystem_name,
		SubsystemResource			*subsystem_resource,
		NotationFile				*subsystem_file,
		const ResourceDirectories	*directories
	)
{
	if (
		!Subsystem::CreateStreamedSubsystem(
			model_file, model_name, subsystem_name,
			subsystem_resource, subsystem_file, directories
		)
	)
	{
		return False;
	}

	subsystem_resource->classID				=
		RegisteredClass::SubsystemMessageManagerClassID;
	subsystem_resource->subsystemModelSize	= 0x38;

	const char
		*terrain_hit_name;
	if (
		!subsystem_file->GetEntry(subsystem_name, "TerrainHitExplosion",
			&terrain_hit_name)
	)
	{
		DEBUG_STREAM << subsystem_name << " missing TerrainHitExplosion!" << endl;
		return False;
	}
	ResourceDescription
		*description =
			resource_file->FindResourceDescription(
				terrain_hit_name,
				ResourceDescription::ModelListResourceType);
	if (description == NULL)
	{
		DEBUG_STREAM << subsystem_name << " cannot find " << terrain_hit_name
			<< " in resource file!" << endl;
		return False;
	}
	subsystem_resource->terrainHitExplosionID = description->resourceID;

	if (
		!subsystem_file->GetEntry(subsystem_name, "RendererCompensateTime",
			&subsystem_resource->rendererCompensateTime)
	)
	{
		DEBUG_STREAM << subsystem_name << " missing RendererCompensateTime" << endl;
		return False;
	}

	Check_Fpu();
	return True;
}