/*
 * This file is part of the TrinityCore Project. See AUTHORS file for Copyright information
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef TRINITYCORE_UNIT_AI_COMMON_H
#define TRINITYCORE_UNIT_AI_COMMON_H

#include "Define.h"

class SpellInfo;
class Unit;

enum Powers : int8;

// EnumUtils: DESCRIBE THIS
enum class EvadeReason
{
    NoHostiles,     // the creature's threat list is empty
    Boundary,       // the creature has moved outside its evade boundary
    NoPath,         // the creature was unable to reach its target for over 5 seconds
    SequenceBreak,  // this is a boss and the pre-requisite encounters for engaging it are not defeated yet
    Other,          // anything else
};

// Selection method used by SelectTarget
enum class SelectTargetMethod
{
    Random,      // just pick a random target
    MaxThreat,   // prefer targets higher in the threat list
    MinThreat,   // prefer targets lower in the threat list
    MaxDistance, // prefer targets further from us
    MinDistance  // prefer targets closer to us
};

// default predicate function to select target based on distance, player and/or aura criteria
struct TC_GAME_API DefaultTargetSelector
{
    // unit: the reference unit
    // dist: if 0: ignored, if > 0: maximum distance to the reference unit, if < 0: minimum distance to the reference unit
    // playerOnly: self explaining
    // withMainTank: allow current tank to be selected
    // aura: if 0: ignored, if > 0: the target shall have the aura, if < 0, the target shall NOT have the aura
    DefaultTargetSelector(Unit const* unit, float dist, bool playerOnly, bool withMainTank, int32 aura);
    bool operator()(Unit const* target) const;

private:
    Unit const* _me;
    float _dist;
    bool _playerOnly;
    Unit const* _exception;
    int32 _aura;
};

// Target selector for spell casts checking range, auras and attributes
/// @todo Add more checks from Spell::CheckCast
struct TC_GAME_API SpellTargetSelector
{
    SpellTargetSelector(Unit* caster, uint32 spellId);
    bool operator()(Unit const* target) const;

private:
    Unit const* _caster;
    SpellInfo const* _spellInfo;
};

// Very simple target selector, will just skip main target
// NOTE: When passing to UnitAI::SelectTarget remember to use 0 as position for random selection
//       because tank will not be in the temporary list
struct TC_GAME_API NonTankTargetSelector
{
    NonTankTargetSelector(Unit* source, bool playerOnly = true) : _source(source), _playerOnly(playerOnly) { }
    bool operator()(Unit const* target) const;

private:
    Unit* _source;
    bool _playerOnly;
};

// Simple selector for units using mana
struct TC_GAME_API PowerUsersSelector
{
    PowerUsersSelector(Unit const* unit, Powers power, float dist, bool playerOnly) : _me(unit), _power(power), _dist(dist), _playerOnly(playerOnly) { }
    bool operator()(Unit const* target) const;

private:
    Unit const* _me;
    Powers const _power;
    float const _dist;
    bool const _playerOnly;
};

struct TC_GAME_API FarthestTargetSelector
{
    FarthestTargetSelector(Unit const* unit, float dist, bool playerOnly, bool inLos) : _me(unit), _dist(dist), _playerOnly(playerOnly), _inLos(inLos) { }
    bool operator()(Unit const* target) const;

private:
    Unit const* _me;
    float _dist;
    bool _playerOnly;
    bool _inLos;
};

#endif // TRINITYCORE_UNIT_AI_COMMON_H