//===========================================================================//
// File:	reservr.cpp                                                         //
// Project: BattleTech           Brick: Mech subsystems                       //
// Contents: Reservoir -- the coolant store                                  //
//---------------------------------------------------------------------------//
// 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// This unpublished sourcecode is PROPRIETARY and CONFIDENTIAL               //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(RESERVR_HPP)
#	include <reservr.hpp>
#endif

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

#if !defined(MECHWEAP_HPP)
#	include <mechweap.hpp>
#endif

#include <math.h>

Derivation
	Reservoir::ClassDerivations(
		HeatSink::ClassDerivations,
		"Reservoir"
	);

//
// The cockpit coolant-flush button (id 4, "InjectCoolant"); ToggleCooling
// (id 3) is inherited from the HeatSink chain.
//
const Reservoir::HandlerEntry
	Reservoir::MessageHandlerEntries[]=
{
	MESSAGE_ENTRY(Reservoir, InjectCoolant)
};

Reservoir::MessageHandlerSet
	Reservoir::MessageHandlers(
		ELEMENTS(Reservoir::MessageHandlerEntries),
		Reservoir::MessageHandlerEntries,
		HeatSink::MessageHandlers
	);

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

//
//#############################################################################
// The coolant store (binary ctor @4af408): CoolantCapacity overlays the
// inherited HeatSink thermalCapacity slot; the charge starts full; the flush
// flow scale is zero (a reservoir never conducts like an ordinary sink).  A
// master reservoir registers the CoolantSimulation performance.
//
// Deferred with the AggregateHeatSink wave: the authentic master path also
// attaches the reservoir into the central bank's radiator loop and rescales
// the capacity by 0.05 x the bank's heat-sink count (the central sink here is
// still a plain HeatSink, which has no count) -- until then the streamed
// capacity is used as-is (a larger tank than authentic; noted).
//#############################################################################
//
Reservoir::Reservoir(
	Mech				*owner,
	int					subsystem_ID,
	SubsystemResource	*r,
	SharedData			&shared_data
):
	HeatSink(owner, subsystem_ID, r, shared_data)
{
	Check(owner);
	Check_Pointer(r);

	reservoirAlarm.Initialize(2);

	squirtEfficiency	= 0.5f;
	thermalCapacity		= r->coolantCapacity;
	coolantSquirtMass	= r->coolantSquirtMass;
	coolantLevel		= thermalCapacity;
	coolantFlowScale	= 0.0f;
	injectAccumulator	= 0.0f;
	reservoirAlarm.SetLevel(0);

	if (getenv("BT_POWER_LOG"))
	{
		DEBUG_STREAM << "[resv] '" << GetName()
			<< "' capacity=" << thermalCapacity
			<< " squirtMass=" << coolantSquirtMass << endl << flush;
	}

	if (owner->GetInstance() != Entity::ReplicantInstance)
	{
		SetPerformance(&Reservoir::CoolantSimulation);

		//
		// The authentic master path scales the tank by the bank's aggregate
		// heat-sink count: capacity = 0.05 x count x streamed (binary
		// @4af408, CoolantCapacityScale byte-verified 0.05).  The linked sink
		// (from the resource) IS the bank.  (The bank-side Attach that routes
		// its DrawCoolant top-ups here joins the attach wave.)
		//
		HeatSink *link = (HeatSink *)linkedSinks.Resolve();
		if (link != NULL
			&& link->IsDerivedFrom(AggregateHeatSink::ClassDerivations))
		{
			Scalar masterScale =
				(Scalar)((AggregateHeatSink *)link)->GetHeatSinkCount();
			thermalCapacity = 0.05f * masterScale * thermalCapacity;
			coolantLevel    = thermalCapacity;
			if (getenv("BT_POWER_LOG"))
			{
				DEBUG_STREAM << "[resv] capacity rescaled by bank count -> "
					<< thermalCapacity << endl << flush;
			}
		}
	}

	Check_Fpu();
}

Reservoir::~Reservoir()
{
}

Logical
	Reservoir::TestClass(Mech &)
{
	return True;
}

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

//
//#############################################################################
// DrawCoolant -- the SOURCE (binary @4af3b0): hand out up to coolantLevel of
// the requested amount and deduct it from the charge.
//#############################################################################
//
Scalar
	Reservoir::DrawCoolant(Scalar requested)
{
	Check(this);

	Scalar supplied = 0.0f;
	if (requested >= 0.0f)
	{
		supplied = requested;
		if (coolantLevel < requested)
		{
			supplied = coolantLevel;
		}
	}
	coolantLevel -= supplied;
	return supplied;
}

//
//#############################################################################
// InjectCoolantMessageHandler -- the cockpit coolant-flush button (binary
// @4aee70, id 4): novice-locked.  Release drops the inject alarm (flush OFF);
// press raises it when the tank holds charge (the flush-cloud effect joins
// the psfx wave) and zeroes the elapsed accumulator.
//#############################################################################
//
void
	Reservoir::InjectCoolantMessageHandler(ReceiverDataMessageOf<int> *message)
{
	Check(this);
	Check(message);

	if (NoviceLockout())
	{
		return;
	}

	if (message->dataContents < 1)
	{
		reservoirAlarm.SetLevel(0);			// release -> flush OFF
	}
	else
	{
		if (reservoirAlarm.GetLevel() != 1 && coolantLevel > 0.0f)
		{
			reservoirAlarm.SetLevel(1);		// flush ON
			if (getenv("BT_MECH_LOG"))
			{
				DEBUG_STREAM << "[resv] FLUSH ON via button (charge="
					<< coolantLevel << ")" << endl << flush;
			}
		}
		injectAccumulator = 0.0f;
	}
	ForceUpdate();
}

//
//#############################################################################
// CoolantSimulation -- the registered Performance (binary @4aef78): while
// injection is active, accumulate elapsed time and run the coolant
// distribution.  The InjectCoolant COCKPIT BUTTON (the id-4 message handler
// that raises the alarm) joins with the cockpit-button message wave; the DEV
// hook BT_FORCE_FLUSH=1 raises it here so the flush machinery is exercisable
// headlessly (one press ~4 s after the sim starts ticking).
//#############################################################################
//
void
	Reservoir::CoolantSimulation(Scalar time_slice)
{
	Check(this);

	{
		static int forceFlush = -1;
		if (forceFlush < 0)
		{
			forceFlush = (getenv("BT_FORCE_FLUSH") != NULL) ? 1 : 0;
		}
		if (forceFlush == 1)
		{
			static Scalar armAccum = 0.0f;
			armAccum += time_slice;
			if (armAccum >= 4.0f && reservoirAlarm.GetLevel() != 1
				&& coolantLevel > 0.0f)
			{
				forceFlush = 2;
				reservoirAlarm.SetLevel(1);
				injectAccumulator = 0.0f;
				if (getenv("BT_MECH_LOG"))
				{
					DEBUG_STREAM << "[resv] FLUSH ON (charge="
						<< coolantLevel << ")" << endl << flush;
				}
			}
		}
	}

	if (reservoirAlarm.GetLevel() == 1)
	{
		injectAccumulator += time_slice;
		InjectCoolant(time_slice);
	}
}

//
//#############################################################################
// InjectCoolant -- the coolant-flush distribution (binary @4aefa4).  Walk the
// roster gathering the flush targets in the authentic pass order -- the
// condensers, then the weapons, then every heat sink, then the linked master
// (the duplicate visits are intentional weighting) -- and squirt
// (coolantSquirtMass x the target's coolantFlowScale x dt) into each,
// crediting a negative pending-heat chill for the moved mass.  Squirts only
// ever leave the tank; the chill only ever cools.
//#############################################################################
//
void
	Reservoir::InjectCoolant(Scalar time_slice)
{
	Check(this);

	if (fabs(coolantLevel) <= 1.0e-4f)			// the tank is empty
	{
		return;
	}

	enum { kMaxWork = 96 };
	HeatSink	*work[kMaxWork];
	int			workCount = 0;
	Entity		*own = (Entity *)owner;
	int			count = own->GetSubsystemCount();
	int			i;

	for (i = 2; i < count && workCount < kMaxWork; ++i)
	{
		Subsystem *s = own->GetSubsystem(i);
		if (s != NULL && s->IsDerivedFrom(Condenser::ClassDerivations))
		{
			work[workCount++] = (HeatSink *)s;
		}
	}
	for (i = 2; i < count && workCount < kMaxWork; ++i)
	{
		Subsystem *s = own->GetSubsystem(i);
		if (s != NULL && s->IsDerivedFrom(MechWeapon::ClassDerivations))
		{
			work[workCount++] = (HeatSink *)s;
		}
	}
	for (i = 2; i < count && workCount < kMaxWork; ++i)
	{
		Subsystem *s = own->GetSubsystem(i);
		if (s != NULL && s->IsDerivedFrom(HeatSink::ClassDerivations))
		{
			work[workCount++] = (HeatSink *)s;
		}
	}
	{
		HeatSink *link = (HeatSink *)linkedSinks.Resolve();
		if (link != NULL && workCount < kMaxWork)
		{
			work[workCount++] = link;
		}
	}

	for (int w = 0; w < workCount; ++w)
	{
		if (fabs(coolantLevel) <= 1.0e-4f)		// ran dry mid-pass
		{
			return;
		}
		HeatSink *sink = work[w];
		if (sink->coolantFlowScale == 0.0f)
		{
			continue;
		}

		//
		// squirt = -(squirtMass x flowScale x dt), clamped to [-coolantLevel, 0].
		//
		Scalar move = -coolantSquirtMass
			* sink->coolantFlowScale
			* time_slice;
		Scalar lo = -coolantLevel;
		if (move < lo)		move = lo;
		if (move > 0.0f)	move = 0.0f;

		//
		// The heat delta riding the moved mass (computed BEFORE the level
		// updates, as in the binary).
		//
		Scalar den = (fabs(sink->coolantLevel) > 1.0e-4f)
			? sink->coolantLevel
			: sink->thermalCapacity;
		Scalar moved = (move < 0.0f) ? -move : move;
		Scalar fracSink = moved / den;
		Scalar fracRes  = moved / coolantLevel;
		Scalar heatDelta =
			sink->heatEnergy * fracSink
			- heatEnergy * fracRes;

		coolantLevel       += move;				// the reservoir drains (move <= 0)
		sink->coolantLevel -= move;				// the sink gains
		if (sink->coolantLevel >= 0.0f)
		{
			if (sink->coolantLevel > sink->thermalCapacity)
			{
				sink->coolantLevel = sink->thermalCapacity;
			}
		}
		else
		{
			sink->coolantLevel = 0.0f;
		}

		Scalar cap = sink->thermalMass * startingTemperature;
		if (heatDelta > cap)
		{
			heatDelta = cap;
		}
		Scalar chill = -heatDelta;
		if (chill > 0.0f)
		{
			chill = 0.0f;						// the flush only ever COOLS
		}
		sink->pendingHeat += chill;
	}
}