/* This file is part of the Spring engine (GPL v2 or later), see LICENSE.html */

#include "System/mmgr.h"

#include <list>
#include <cstdlib>
#include <cstring>

#include "LosHandler.h"
#include "ModInfo.h"

#include "Sim/Units/Unit.h"
#include "Sim/Misc/TeamHandler.h"
#include "Map/ReadMap.h"
#include "System/Log/ILog.h"
#include "System/TimeProfiler.h"
#include "System/creg/STL_Deque.h"
#include "System/creg/STL_List.h"

using std::min;
using std::max;

CR_BIND(LosInstance, );
CR_BIND(CLosHandler, );
CR_BIND(CLosHandler::DelayedInstance, );

CR_REG_METADATA(LosInstance,(
//		CR_MEMBER(losSquares),
		CR_MEMBER(losSize),
		CR_MEMBER(airLosSize),
		CR_MEMBER(refCount),
		CR_MEMBER(allyteam),
		CR_MEMBER(basePos),
		CR_MEMBER(baseSquare),
		CR_MEMBER(baseAirPos),
		CR_MEMBER(hashNum),
		CR_MEMBER(baseHeight),
		CR_MEMBER(toBeDeleted),
		CR_RESERVED(16)
		));

void CLosHandler::PostLoad()
{
	for (int a = 0; a < LOSHANDLER_MAGIC_PRIME; ++a) {
		for (std::list<LosInstance*>::iterator li = instanceHash[a].begin(); li != instanceHash[a].end(); ++li) {
			if ((*li)->refCount) {
				LosAdd(*li);
			}
		}
	}
}

CR_REG_METADATA(CLosHandler,(
		CR_MEMBER(instanceHash),
		CR_MEMBER(toBeDeleted),
		CR_MEMBER(delayQue),
		CR_RESERVED(8),
		CR_POSTLOAD(PostLoad)
		));

CR_REG_METADATA_SUB(CLosHandler,DelayedInstance,(
		CR_MEMBER(instance),
		CR_MEMBER(timeoutTime)));


//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////


CLosHandler* loshandler;


CLosHandler::CLosHandler() :
	losMaps(teamHandler->ActiveAllyTeams()),
	airLosMaps(teamHandler->ActiveAllyTeams()),
	// airAlgo(int2(airSizeX, airSizeY), -1e6f, 15, readmap->GetMIPHeightMapSynced(airMipLevel)),
	losMipLevel(modInfo.losMipLevel),
	airMipLevel(modInfo.airMipLevel),
	losDiv(SQUARE_SIZE * (1 << losMipLevel)),
	airDiv(SQUARE_SIZE * (1 << airMipLevel)),
	invLosDiv(1.0f / losDiv),
	invAirDiv(1.0f / airDiv),
	airSizeX(std::max(1, gs->mapx >> airMipLevel)),
	airSizeY(std::max(1, gs->mapy >> airMipLevel)),
	losSizeX(std::max(1, gs->mapx >> losMipLevel)),
	losSizeY(std::max(1, gs->mapy >> losMipLevel)),
	requireSonarUnderWater(modInfo.requireSonarUnderWater),
	losAlgo(int2(losSizeX, losSizeY), -1e6f, 15, readmap->GetMIPHeightMapSynced(losMipLevel))
{
	for (int a = 0; a < teamHandler->ActiveAllyTeams(); ++a) {
		losMaps[a].SetSize(losSizeX, losSizeY);
		airLosMaps[a].SetSize(airSizeX, airSizeY);
	}
}


CLosHandler::~CLosHandler()
{
	for (int a = 0; a < LOSHANDLER_MAGIC_PRIME; ++a) {
		for (std::list<LosInstance*>::iterator li = instanceHash[a].begin(); li != instanceHash[a].end(); ++li) {
			LosInstance* i = *li;
			i->_DestructInstance(i);
			mempool.Free(i, sizeof(LosInstance));
		}
	}

}


void CLosHandler::MoveUnit(CUnit* unit, bool redoCurrent)
{
	SCOPED_TIMER("LOSHandler::MoveUnit");

	// NOTE: under normal circumstances, this only gets called if a unit
	// has moved to a new map square since its last SlowUpdate cycle, so
	// any units that changed position between enabling and disabling of
	// globalLOS and *stopped* will continue to provide LOS at their old
	// square *after* it is disabled (until they are moved again)
	if (gs->globalLOS[unit->allyteam]) { return; }
	if (unit->losRadius <= 0 && unit->airLosRadius <= 0) {
		return;
	}

	unit->lastLosUpdate = gs->frameNum;

	const float3& losPos = unit->pos;
	const int allyteam = unit->allyteam;

	const int baseX = max(0, min(losSizeX - 1, int(losPos.x * invLosDiv)));
	const int baseY = max(0, min(losSizeY - 1, int(losPos.z * invLosDiv)));
	const int baseSquare = baseY * losSizeX + baseX;
	const int baseAirX = max(0, min(airSizeX - 1, int(losPos.x * invAirDiv)));
	const int baseAirY = max(0, min(airSizeY - 1, int(losPos.z * invAirDiv)));

	LosInstance* instance = NULL;
	if (redoCurrent) {
		if (!unit->los) {
			return;
		}
		instance = unit->los;
		CleanupInstance(instance);
		instance->losSquares.clear();
		instance->basePos.x = baseX;
		instance->basePos.y = baseY;
		instance->baseSquare = baseSquare; //this could be a problem if several units are sharing the same instance
		instance->baseAirPos.x = baseAirX;
		instance->baseAirPos.y = baseAirY;
	} else {
		if (unit->los && (unit->los->baseSquare == baseSquare)) {
			return;
		}

		FreeInstance(unit->los);
		const int hash = GetHashNum(unit);

		std::list<LosInstance*>::iterator lii;
		for (lii = instanceHash[hash].begin(); lii != instanceHash[hash].end(); ++lii) {
			if ((*lii)->baseSquare == baseSquare         &&
			    (*lii)->losSize    == unit->losRadius    &&
			    (*lii)->airLosSize == unit->airLosRadius &&
			    (*lii)->baseHeight == unit->losHeight    &&
			    (*lii)->allyteam   == allyteam) {
				AllocInstance(*lii);
				unit->los = *lii;
				return;
			}
		}

		instance = new(mempool.Alloc(sizeof(LosInstance))) LosInstance(
			unit->losRadius,
			unit->airLosRadius,
			allyteam,
			int2(baseX,baseY),
			baseSquare,
			int2(baseAirX, baseAirY),
			hash, unit->losHeight
		);

		instanceHash[hash].push_back(instance);
		unit->los = instance;
	}

	LosAdd(instance);
}


void CLosHandler::LosAdd(LosInstance* instance)
{
	assert(instance);
	assert(teamHandler->IsValidAllyTeam(instance->allyteam));

	losAlgo.LosAdd(instance->basePos, instance->losSize, instance->baseHeight, instance->losSquares);

	if (instance->losSize > 0) { losMaps[instance->allyteam].AddMapSquares(instance->losSquares, instance->allyteam, 1); }
	if (instance->airLosSize > 0) { airLosMaps[instance->allyteam].AddMapArea(instance->baseAirPos, instance->allyteam, instance->airLosSize, 1); }
}


void CLosHandler::FreeInstance(LosInstance* instance)
{
	if (instance == 0)
		return;

	instance->refCount--;

	if (instance->refCount == 0) {
		CleanupInstance(instance);

		if (!instance->toBeDeleted) {
			instance->toBeDeleted = true;
			toBeDeleted.push_back(instance);
		}

		if (instance->hashNum >= LOSHANDLER_MAGIC_PRIME || instance->hashNum < 0) {
			LOG_L(L_WARNING,
					"[LosHandler::FreeInstance][1] bad LOS-instance hash (%d)",
					instance->hashNum);
		}

		if (toBeDeleted.size() > 500) {
			LosInstance* i = toBeDeleted.front();
			toBeDeleted.pop_front();

			if (i->hashNum >= LOSHANDLER_MAGIC_PRIME || i->hashNum < 0) {
				LOG_L(L_WARNING,
						"[LosHandler::FreeInstance][2] bad LOS-instance hash (%d)",
						i->hashNum);
				return;
			}

			i->toBeDeleted = false;

			if (i->refCount == 0) {
				std::list<LosInstance*>::iterator lii;

				for (lii = instanceHash[i->hashNum].begin(); lii != instanceHash[i->hashNum].end(); ++lii) {
					if ((*lii) == i) {
						instanceHash[i->hashNum].erase(lii);
						i->_DestructInstance(i);
						mempool.Free(i, sizeof(LosInstance));
						break;
					}
				}
			}
		}
	}
}


int CLosHandler::GetHashNum(CUnit* unit)
{
	const unsigned int t =
		(unit->mapSquare * unit->losRadius + unit->allyteam) ^
		(*(unsigned int*) &unit->losHeight);
	//! hash-value range is [0, LOSHANDLER_MAGIC_PRIME - 1]
	return (t % LOSHANDLER_MAGIC_PRIME);
}


void CLosHandler::AllocInstance(LosInstance* instance)
{
	if (instance->refCount == 0) {
		LosAdd(instance);
	}
	instance->refCount++;
}


void CLosHandler::CleanupInstance(LosInstance* instance)
{
	if (instance->losSize > 0) { losMaps[instance->allyteam].AddMapSquares(instance->losSquares, instance->allyteam, -1); }
	if (instance->airLosSize > 0) { airLosMaps[instance->allyteam].AddMapArea(instance->baseAirPos, instance->allyteam, instance->airLosSize, -1); }
}


void CLosHandler::Update(void)
{
	while (!delayQue.empty() && delayQue.front().timeoutTime < gs->frameNum) {
		FreeInstance(delayQue.front().instance);
		delayQue.pop_front();
	}
}


void CLosHandler::DelayedFreeInstance(LosInstance* instance)
{
	DelayedInstance di;
	di.instance = instance;
	di.timeoutTime = (gs->frameNum + (GAME_SPEED + (GAME_SPEED >> 1)));

	delayQue.push_back(di);
}