/*
* PriorityEvaluator.cpp, part of VCMI engine
*
* Authors: listed in file AUTHORS in main folder
*
* License: GNU General Public License v2.0 or later
* Full text of license available in license.txt file, in main folder
*
*/
#include "StdInc.h"
#include "PriorityEvaluator.h"
#include <limits>

#include "../../../lib/mapObjects/MapObjects.h"
#include "../../../lib/mapObjects/CommonConstructors.h"
#include "../../../lib/CCreatureHandler.h"
#include "../../../lib/CPathfinder.h"
#include "../../../lib/CGameStateFwd.h"
#include "../../../lib/VCMI_Lib.h"
#include "../../../CCallback.h"
#include "../../../lib/filesystem/Filesystem.h"
#include "../VCAI.h"
#include "../AIhelper.h"
#include "../Engine/Nullkiller.h"
#include "../Goals/ExecuteHeroChain.h"

#define MIN_AI_STRENGHT (0.5f) //lower when combat AI gets smarter
#define UNGUARDED_OBJECT (100.0f) //we consider unguarded objects 100 times weaker than us

struct BankConfig;
class CBankInfo;
class Engine;
class InputVariable;
class CGTownInstance;

extern boost::thread_specific_ptr<CCallback> cb;
extern boost::thread_specific_ptr<VCAI> ai;

PriorityEvaluator::~PriorityEvaluator()
{
	delete engine;
}

void PriorityEvaluator::initVisitTile()
{
	auto file = CResourceHandler::get()->load(ResourceID("config/ai/object-priorities.txt"))->readAll();
	std::string str = std::string((char *)file.first.get(), file.second);
	engine = fl::FllImporter().fromString(str);
	armyLossPersentageVariable = engine->getInputVariable("armyLoss");
	heroRoleVariable = engine->getInputVariable("heroRole");
	dangerVariable = engine->getInputVariable("danger");
	mainTurnDistanceVariable = engine->getInputVariable("mainTurnDistance");
	scoutTurnDistanceVariable = engine->getInputVariable("scoutTurnDistance");
	goldRewardVariable = engine->getInputVariable("goldReward");
	armyRewardVariable = engine->getInputVariable("armyReward");
	skillRewardVariable = engine->getInputVariable("skillReward");
	rewardTypeVariable = engine->getInputVariable("rewardType");
	closestHeroRatioVariable = engine->getInputVariable("closestHeroRatio");
	strategicalValueVariable = engine->getInputVariable("strategicalValue");
	value = engine->getOutputVariable("Value");
}

int32_t estimateTownIncome(const CGObjectInstance * target, const CGHeroInstance * hero)
{
	auto relations = cb->getPlayerRelations(hero->tempOwner, target->tempOwner);

	if(relations != PlayerRelations::ENEMIES)
		return 0; // if we already own it, no additional reward will be received by just visiting it

	auto town = cb->getTown(target->id);
	auto isNeutral = target->tempOwner == PlayerColor::NEUTRAL;
	auto isProbablyDeveloped = !isNeutral && town->hasFort();

	return isProbablyDeveloped ? 1500 : 500;
}

TResources getCreatureBankResources(const CGObjectInstance * target, const CGHeroInstance * hero)
{
	auto objectInfo = VLC->objtypeh->getHandlerFor(target->ID, target->subID)->getObjectInfo(target->appearance);
	CBankInfo * bankInfo = dynamic_cast<CBankInfo *>(objectInfo.get());
	auto resources = bankInfo->getPossibleResourcesReward();

	return resources;
}

uint64_t getCreatureBankArmyReward(const CGObjectInstance * target, const CGHeroInstance * hero)
{
	auto objectInfo = VLC->objtypeh->getHandlerFor(target->ID, target->subID)->getObjectInfo(target->appearance);
	CBankInfo * bankInfo = dynamic_cast<CBankInfo *>(objectInfo.get());
	auto creatures = bankInfo->getPossibleCreaturesReward();
	uint64_t result = 0;

	for(auto c : creatures)
	{
		result += c.type->AIValue * c.count;
	}

	return result;
}

uint64_t getDwellingScore(const CGObjectInstance * target, bool checkGold)
{
	auto dwelling = dynamic_cast<const CGDwelling *>(target);
	uint64_t score = 0;
	
	for(auto & creLevel : dwelling->creatures)
	{
		if(creLevel.first && creLevel.second.size())
		{
			auto creature = creLevel.second.back().toCreature();
			auto creaturesAreFree = creature->level == 1;
			if(!creaturesAreFree && checkGold && !cb->getResourceAmount().canAfford(creature->cost * creLevel.first))
				continue;

			score += creature->AIValue * creLevel.first;
		}
	}

	return score;
}

uint64_t evaluateArtifactArmyValue(CArtifactInstance * art)
{
	if(art->artType->id == ArtifactID::SPELL_SCROLL)
		return 1500;

	auto statsValue =
		4 * art->valOfBonuses(Bonus::LAND_MOVEMENT)
		+ 700 * art->valOfBonuses(Bonus::MORALE)
		+ 700 * art->getAttack(false)
		+ 700 * art->getDefence(false)
		+ 700 * art->valOfBonuses(Bonus::PRIMARY_SKILL, PrimarySkill::KNOWLEDGE)
		+ 700 * art->valOfBonuses(Bonus::PRIMARY_SKILL, PrimarySkill::SPELL_POWER)
		+ 700 * art->getDefence(false)
		+ 500 * art->valOfBonuses(Bonus::LUCK);

	auto classValue = 0;

	switch(art->artType->aClass)
	{
	case CArtifact::EartClass::ART_MINOR:
		classValue = 1000;
		break;

	case CArtifact::EartClass::ART_MAJOR:
		classValue = 3000;
		break;
	case CArtifact::EartClass::ART_RELIC:
	case CArtifact::EartClass::ART_SPECIAL:
		classValue = 8000;
		break;
	}

	return statsValue > classValue ? statsValue : classValue;
}

uint64_t getArmyReward(const CGObjectInstance * target, const CGHeroInstance * hero, const CCreatureSet * army, bool checkGold)
{
	const float enemyArmyEliminationRewardRatio = 0.5f;

	if(!target)
		return 0;

	switch(target->ID)
	{
	case Obj::TOWN:
		return target->tempOwner == PlayerColor::NEUTRAL ? 1000 : 10000;
	case Obj::HILL_FORT:
		return ai->ah->calculateCreateresUpgrade(army, target, cb->getResourceAmount()).upgradeValue;
	case Obj::CREATURE_BANK:
		return getCreatureBankArmyReward(target, hero);
	case Obj::CREATURE_GENERATOR1:
	case Obj::CREATURE_GENERATOR2:
	case Obj::CREATURE_GENERATOR3:
	case Obj::CREATURE_GENERATOR4:
		return getDwellingScore(target, checkGold);
	case Obj::CRYPT:
	case Obj::SHIPWRECK:
	case Obj::SHIPWRECK_SURVIVOR:
	case Obj::WARRIORS_TOMB:
		return 1000;
	case Obj::ARTIFACT:
		return evaluateArtifactArmyValue(dynamic_cast<const CGArtifact *>(target)->storedArtifact);
	case Obj::DRAGON_UTOPIA:
		return 10000;
	case Obj::HERO:
		return cb->getPlayerRelations(target->tempOwner, ai->playerID) == PlayerRelations::ENEMIES
			? enemyArmyEliminationRewardRatio * dynamic_cast<const CGHeroInstance *>(target)->getArmyStrength()
			: 0;
	default:
		return 0;
	}
}

float getStrategicalValue(const CGObjectInstance * target);

float getEnemyHeroStrategicalValue(const CGHeroInstance * enemy)
{
	auto objectsUnderTreat = ai->nullkiller->dangerHitMap->getOneTurnAccessibleObjects(enemy);
	float objectValue = 0;

	for(auto obj : objectsUnderTreat)
	{
		vstd::amax(objectValue, getStrategicalValue(obj));
	}

	return objectValue / 2.0f + enemy->level / 15.0f;
}

float getResourceRequirementStrength(int resType)
{
	TResources requiredResources = ai->nullkiller->buildAnalyzer->getResourcesRequiredNow();
	TResources dailyIncome = ai->nullkiller->buildAnalyzer->getDailyIncome();

	if(requiredResources[resType] == 0)
		return 0;

	if(dailyIncome[resType] == 0)
		return 1;

	return (float)requiredResources[resType] / dailyIncome[resType] / 3;
}

float getTotalResourceRequirementStrength(int resType)
{
	TResources requiredResources = ai->nullkiller->buildAnalyzer->getTotalResourcesRequired();
	TResources dailyIncome = ai->nullkiller->buildAnalyzer->getDailyIncome();

	if(requiredResources[resType] == 0)
		return 0;

	if(dailyIncome[resType] == 0)
		return requiredResources[resType] / 30;

	return (float)requiredResources[resType] / dailyIncome[resType] / 30;
}

float getStrategicalValue(const CGObjectInstance * target)
{
	if(!target)
		return 0;

	switch(target->ID)
	{
	case Obj::MINE:
		return target->subID == Res::GOLD ? 0.8f : 0.05f + 0.3f * getTotalResourceRequirementStrength(target->subID) + 0.5f * getResourceRequirementStrength(target->subID);

	case Obj::RESOURCE:
		return target->subID == Res::GOLD ? 0 : 0.5f * getResourceRequirementStrength(target->subID);

	case Obj::TOWN:
		return target->tempOwner == PlayerColor::NEUTRAL ? 0.5 : 1;

	case Obj::HERO:
		return cb->getPlayerRelations(target->tempOwner, ai->playerID) == PlayerRelations::ENEMIES
			? getEnemyHeroStrategicalValue(dynamic_cast<const CGHeroInstance *>(target))
			: 0;
	default:
		return 0;
	}
}

float evaluateWitchHutSkillScore(const CGWitchHut * hut, const CGHeroInstance * hero, HeroRole role)
{
	if(!hut->wasVisited(hero->tempOwner))
		return role == HeroRole::SCOUT ? 2 : 0;

	auto skill = SecondarySkill(hut->ability);

	if(hero->getSecSkillLevel(skill) != SecSkillLevel::NONE
		|| hero->secSkills.size() >= GameConstants::SKILL_PER_HERO)
		return 0;

	auto score = ai->ah->evaluateSecSkill(skill, hero);

	return score >= 2 ? (role == HeroRole::MAIN ? 10 : 4) : score;
}

float getSkillReward(const CGObjectInstance * target, const CGHeroInstance * hero, HeroRole role)
{
	const float enemyHeroEliminationSkillRewardRatio = 0.5f;

	if(!target)
		return 0;

	switch(target->ID)
	{
	case Obj::STAR_AXIS:
	case Obj::SCHOLAR:
	case Obj::SCHOOL_OF_MAGIC:
	case Obj::SCHOOL_OF_WAR:
	case Obj::GARDEN_OF_REVELATION:
	case Obj::MARLETTO_TOWER:
	case Obj::MERCENARY_CAMP:
	case Obj::SHRINE_OF_MAGIC_GESTURE:
	case Obj::SHRINE_OF_MAGIC_INCANTATION:
	case Obj::TREE_OF_KNOWLEDGE:
		return 1;
	case Obj::LEARNING_STONE:
		return 1.0f / std::sqrtf(hero->level);
	case Obj::ARENA:
	case Obj::SHRINE_OF_MAGIC_THOUGHT:
		return 2;
	case Obj::LIBRARY_OF_ENLIGHTENMENT:
		return 8;
	case Obj::WITCH_HUT:
		return evaluateWitchHutSkillScore(dynamic_cast<const CGWitchHut *>(target), hero, role);
	case Obj::HERO:
		return cb->getPlayerRelations(target->tempOwner, ai->playerID) == PlayerRelations::ENEMIES
			? enemyHeroEliminationSkillRewardRatio * dynamic_cast<const CGHeroInstance *>(target)->level
			: 0;
	default:
		return 0;
	}
}

int32_t getArmyCost(const CArmedInstance * army)
{
	int32_t value = 0;

	for(auto stack : army->Slots())
	{
		value += stack.second->getCreatureID().toCreature()->cost[Res::GOLD] * stack.second->count;
	}

	return value;
}

/// Gets aproximated reward in gold. Daily income is multiplied by 5
int32_t getGoldReward(const CGObjectInstance * target, const CGHeroInstance * hero)
{
	if(!target)
		return 0;

	const int dailyIncomeMultiplier = 5;
	const float enemyArmyEliminationGoldRewardRatio = 0.2f;
	const int32_t heroEliminationBonus = GameConstants::HERO_GOLD_COST / 2;
	auto isGold = target->subID == Res::GOLD; // TODO: other resorces could be sold but need to evaluate market power

	switch(target->ID)
	{
	case Obj::RESOURCE:
		return isGold ? 600 : 100;
	case Obj::TREASURE_CHEST:
		return 1500;
	case Obj::WATER_WHEEL:
		return 1000;
	case Obj::TOWN:
		return dailyIncomeMultiplier * estimateTownIncome(target, hero);
	case Obj::MINE:
	case Obj::ABANDONED_MINE:
		return dailyIncomeMultiplier * (isGold ? 1000 : 75);
	case Obj::MYSTICAL_GARDEN:
	case Obj::WINDMILL:
		return 100;
	case Obj::CAMPFIRE:
		return 800;
	case Obj::WAGON:
		return 100;
	case Obj::CREATURE_BANK:
		return getCreatureBankResources(target, hero)[Res::GOLD];
	case Obj::CRYPT:
	case Obj::DERELICT_SHIP:
		return 3000;
	case Obj::DRAGON_UTOPIA:
		return 10000;
	case Obj::SEA_CHEST:
		return 1500;
	case Obj::HERO:
		return cb->getPlayerRelations(target->tempOwner, ai->playerID) == PlayerRelations::ENEMIES
			? heroEliminationBonus + enemyArmyEliminationGoldRewardRatio * getArmyCost(dynamic_cast<const CGHeroInstance *>(target))
			: 0;
	default:
		return 0;
	}
}

class ExecuteHeroChainEvaluationContextBuilder : public IEvaluationContextBuilder
{
public:
	virtual Goals::EvaluationContext buildEvaluationContext(Goals::TSubgoal task) const override
	{
		Goals::ExecuteHeroChain & chain = dynamic_cast<Goals::ExecuteHeroChain &>(*task);
		auto evaluationContext = task->evaluationContext;

		auto heroPtr = task->hero;
		const CGObjectInstance * target = cb->getObj((ObjectInstanceID)task->objid, false);
		auto day = cb->getDate(Date::DAY);
		auto hero = heroPtr.get();
		bool checkGold = evaluationContext.danger == 0;

		evaluationContext.armyLossPersentage = task->evaluationContext.armyLoss / (double)task->evaluationContext.heroStrength;
		evaluationContext.heroRole = ai->ah->getHeroRole(heroPtr);
		evaluationContext.goldReward = getGoldReward(target, hero);
		evaluationContext.armyReward = getArmyReward(target, hero, chain.getPath().heroArmy, checkGold);
		evaluationContext.skillReward = getSkillReward(target, hero, evaluationContext.heroRole);
		evaluationContext.strategicalValue = getStrategicalValue(target);

		return evaluationContext;
	}
};

class BuildThisEvaluationContextBuilder : public IEvaluationContextBuilder
{
public:
	virtual Goals::EvaluationContext buildEvaluationContext(Goals::TSubgoal task) const override
	{
		Goals::EvaluationContext evaluationContext;
		Goals::BuildThis & buildThis = dynamic_cast<Goals::BuildThis &>(*task);
		auto & bi = buildThis.buildingInfo;
		
		evaluationContext.goldReward = bi.dailyIncome[Res::GOLD] / 2;
		evaluationContext.heroRole = HeroRole::MAIN;
		evaluationContext.movementCostByRole[evaluationContext.heroRole] = bi.prerequisitesCount;
		evaluationContext.armyReward = 0;
		evaluationContext.strategicalValue = buildThis.townInfo.armyScore / 50000.0;

		if(bi.creatureID != CreatureID::NONE)
		{
			evaluationContext.strategicalValue += 0.5f + 0.1f * bi.creatureLevel;

			if(bi.baseCreatureID == bi.creatureID)
			{
				evaluationContext.armyReward = ai->ah->evaluateStackPower(bi.creatureID.toCreature(), bi.creatureGrows);
			}
			
			auto creaturesToUpgrade = ai->ah->getTotalCreaturesAvailable(bi.baseCreatureID);
			auto upgradedPower = ai->ah->evaluateStackPower(bi.creatureID.toCreature(), creaturesToUpgrade.count);

			evaluationContext.armyReward = upgradedPower - creaturesToUpgrade.power;
		}
		
		return evaluationContext;
	}
};

PriorityEvaluator::PriorityEvaluator()
{
	initVisitTile();
	evaluationContextBuilders[Goals::EXECUTE_HERO_CHAIN] = std::make_shared<ExecuteHeroChainEvaluationContextBuilder>();
	evaluationContextBuilders[Goals::BUILD_STRUCTURE] = std::make_shared<BuildThisEvaluationContextBuilder>();
}

Goals::EvaluationContext PriorityEvaluator::buildEvaluationContext(Goals::TSubgoal goal) const
{
	auto builder = evaluationContextBuilders.find(goal->goalType);

	if(builder == evaluationContextBuilders.end())
		return goal->evaluationContext;

	return builder->second->buildEvaluationContext(goal);
}

/// distance
/// nearest hero?
/// gold income
/// army income
/// hero strength - hero skills
/// danger
/// importance
float PriorityEvaluator::evaluate(Goals::TSubgoal task)
{
	if(task->priority > 0)
		return task->priority;

	auto evaluationContext = buildEvaluationContext(task);

	int rewardType = (evaluationContext.goldReward > 0 ? 1 : 0) 
		+ (evaluationContext.armyReward > 0 ? 1 : 0)
		+ (evaluationContext.skillReward > 0 ? 1 : 0)
		+ (evaluationContext.strategicalValue > 0 ? 1 : 0);
	
	double result = 0;

	try
	{
		armyLossPersentageVariable->setValue(evaluationContext.armyLossPersentage);
		heroRoleVariable->setValue(evaluationContext.heroRole);
		mainTurnDistanceVariable->setValue(evaluationContext.movementCostByRole[HeroRole::MAIN]);
		scoutTurnDistanceVariable->setValue(evaluationContext.movementCostByRole[HeroRole::SCOUT]);
		goldRewardVariable->setValue(evaluationContext.goldReward);
		armyRewardVariable->setValue(evaluationContext.armyReward);
		skillRewardVariable->setValue(evaluationContext.skillReward);
		dangerVariable->setValue(evaluationContext.danger);
		rewardTypeVariable->setValue(rewardType);
		closestHeroRatioVariable->setValue(evaluationContext.closestWayRatio);
		strategicalValueVariable->setValue(evaluationContext.strategicalValue);

		engine->process();
		//engine.process(VISIT_TILE); //TODO: Process only Visit_Tile
		result = value->getValue();
	}
	catch(fl::Exception & fe)
	{
		logAi->error("evaluate VisitTile: %s", fe.getWhat());
	}
	assert(result >= 0);

#ifdef VCMI_TRACE_PATHFINDER
	logAi->trace("Evaluated %s, loss: %f, turns main: %f, scout: %f, gold: %d, army gain: %d, danger: %d, role: %s, strategical value: %f, result %f",
		task->name(),
		evaluationContext.armyLossPersentage,
		evaluationContext.movementCostByRole[HeroRole::MAIN],
		evaluationContext.movementCostByRole[HeroRole::SCOUT],
		evaluationContext.goldReward,
		evaluationContext.armyReward,
		evaluationContext.danger,
		evaluationContext.heroRole ? "scout" : "main",
		evaluationContext.strategicalValue,
		result);
#endif

	return result;
}