/*
 * AIUtility.h, 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
 *
 */
#pragma once

#include "../../lib/VCMI_Lib.h"
#include "../../lib/CBuildingHandler.h"
#include "../../lib/CCreatureHandler.h"
#include "../../lib/CTownHandler.h"
#include "../../lib/spells/CSpellHandler.h"
#include "../../lib/CStopWatch.h"
#include "../../lib/mapObjects/CObjectHandler.h"
#include "../../lib/mapObjects/CGHeroInstance.h"
#include "../../lib/CPathfinder.h"

class CCallback;
struct creInfo;

typedef const int3 & crint3;
typedef const std::string & crstring;
typedef std::pair<ui32, std::vector<CreatureID>> dwellingContent;

const int GOLD_MINE_PRODUCTION = 1000, WOOD_ORE_MINE_PRODUCTION = 2, RESOURCE_MINE_PRODUCTION = 1;
const int ACTUAL_RESOURCE_COUNT = 7;
const int ALLOWED_ROAMING_HEROES = 8;

//implementation-dependent
extern const double SAFE_ATTACK_CONSTANT;
extern const int GOLD_RESERVE;

//provisional class for AI to store a reference to an owned hero object
//checks if it's valid on access, should be used in place of const CGHeroInstance*

struct DLL_EXPORT HeroPtr
{
	const CGHeroInstance * h;
	ObjectInstanceID hid;

public:
	std::string name;


	HeroPtr();
	HeroPtr(const CGHeroInstance * H);
	~HeroPtr();

	operator bool() const
	{
		return validAndSet();
	}

	bool operator<(const HeroPtr & rhs) const;
	const CGHeroInstance * operator->() const;
	const CGHeroInstance * operator*() const; //not that consistent with -> but all interfaces use CGHeroInstance*, so it's convenient
	bool operator==(const HeroPtr & rhs) const;

	const CGHeroInstance * get(bool doWeExpectNull = false) const;
	bool validAndSet() const;


	template<typename Handler> void serialize(Handler & h, const int version)
	{
		h & this->h;
		h & hid;
		h & name;
	}
};

enum BattleState
{
	NO_BATTLE,
	UPCOMING_BATTLE,
	ONGOING_BATTLE,
	ENDING_BATTLE
};

// AI lives in a dangerous world. CGObjectInstances under pointer may got deleted/hidden.
// This class stores object id, so we can detect when we lose access to the underlying object.
struct ObjectIdRef
{
	ObjectInstanceID id;

	const CGObjectInstance * operator->() const;
	operator const CGObjectInstance *() const;

	ObjectIdRef(ObjectInstanceID _id);
	ObjectIdRef(const CGObjectInstance * obj);

	bool operator<(const ObjectIdRef & rhs) const;


	template<typename Handler> void serialize(Handler & h, const int version)
	{
		h & id;
	}
};

struct TimeCheck
{
	CStopWatch time;
	std::string txt;
	TimeCheck(crstring TXT)
		: txt(TXT)
	{
	}

	~TimeCheck()
	{
		logAi->trace("Time of %s was %d ms.", txt, time.getDiff());
	}
};

//TODO: replace with vstd::
struct AtScopeExit
{
	std::function<void()> foo;
	AtScopeExit(const std::function<void()> & FOO)
		: foo(FOO)
	{}
	~AtScopeExit()
	{
		foo();
	}
};


class ObjsVector : public std::vector<ObjectIdRef>
{
};

template<int id>
bool objWithID(const CGObjectInstance * obj)
{
	return obj->ID == id;
}

struct creInfo
{
	int count;
	CreatureID creID;
	CCreature * cre;
	int level;
};
creInfo infoFromDC(const dwellingContent & dc);

void foreach_tile_pos(std::function<void(const int3 & pos)> foo);
void foreach_tile_pos(CCallback * cbp, std::function<void(CCallback * cbp, const int3 & pos)> foo); // avoid costly retrieval of thread-specific pointer
void foreach_neighbour(const int3 & pos, std::function<void(const int3 & pos)> foo);
void foreach_neighbour(CCallback * cbp, const int3 & pos, std::function<void(CCallback * cbp, const int3 & pos)> foo); // avoid costly retrieval of thread-specific pointer

int howManyTilesWillBeDiscovered(const int3 & pos, int radious, CCallback * cbp, HeroPtr hero);
void getVisibleNeighbours(const std::vector<int3> & tiles, std::vector<int3> & out);

bool canBeEmbarkmentPoint(const TerrainTile * t, bool fromWater);
bool isBlockedBorderGate(int3 tileToHit);
bool isBlockVisitObj(const int3 & pos);

bool isWeeklyRevisitable(const CGObjectInstance * obj);
bool shouldVisit(HeroPtr h, const CGObjectInstance * obj);

ui64 evaluateDanger(const CGObjectInstance * obj);
ui64 evaluateDanger(crint3 tile, const CGHeroInstance * visitor);
bool isSafeToVisit(HeroPtr h, crint3 tile);

bool compareMovement(HeroPtr lhs, HeroPtr rhs);
bool compareHeroStrength(HeroPtr h1, HeroPtr h2);
bool compareArmyStrength(const CArmedInstance * a1, const CArmedInstance * a2);
bool compareArtifacts(const CArtifactInstance * a1, const CArtifactInstance * a2);
ui64 howManyReinforcementsCanBuy(HeroPtr h, const CGTownInstance * t);
ui64 howManyReinforcementsCanGet(HeroPtr h, const CGTownInstance * t);
int3 whereToExplore(HeroPtr h);

class CDistanceSorter
{
	const CGHeroInstance * hero;

public:
	CDistanceSorter(const CGHeroInstance * hero)
		: hero(hero)
	{
	}
	bool operator()(const CGObjectInstance * lhs, const CGObjectInstance * rhs);
};