/*
 * Copyright (C) 2005-2009 MaNGOS <http://getmangos.com/>
 *
 * Copyright (C) 2008-2009 Trinity <http://www.trinitycore.org/>
 *
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "UnitAI.h"
#include "Player.h"
#include "Creature.h"
#include "SpellAuras.h"
#include "SpellMgr.h"
#include "CreatureAIImpl.h"

void UnitAI::AttackStart(Unit *victim)
{
    if(victim && me->Attack(victim, true))
        me->GetMotionMaster()->MoveChase(victim);
}

void UnitAI::AttackStartCaster(Unit *victim, float dist)
{
    if(victim && me->Attack(victim, false))
        me->GetMotionMaster()->MoveChase(victim, dist);
}

void UnitAI::DoMeleeAttackIfReady()
{
    if(me->hasUnitState(UNIT_STAT_CASTING))
        return;

    //Make sure our attack is ready and we aren't currently casting before checking distance
    if (me->isAttackReady())
    {
        //If we are within range melee the target
        if (me->IsWithinMeleeRange(me->getVictim()))
        {
            me->AttackerStateUpdate(me->getVictim());
            me->resetAttackTimer();
        }
    }
    if (me->haveOffhandWeapon() && me->isAttackReady(OFF_ATTACK))
    {
        //If we are within range melee the target
        if (me->IsWithinMeleeRange(me->getVictim()))
        {
            me->AttackerStateUpdate(me->getVictim(), OFF_ATTACK);
            me->resetAttackTimer(OFF_ATTACK);
        }
    }
}

bool UnitAI::DoSpellAttackIfReady(uint32 spell)
{
    if(me->hasUnitState(UNIT_STAT_CASTING))
        return true;

    if(me->isAttackReady())
    {
        if(me->IsWithinCombatRange(me->getVictim(), GetSpellMaxRange(spell, false)))
        {
            me->CastSpell(me->getVictim(), spell, false);
            me->resetAttackTimer();
        }
        else
            return false;
    }
    return true;
}

inline bool SelectTargetHelper(const Unit * me, const Unit * target, const bool &playerOnly, const float &dist, const int32 &aura)
{
    if(playerOnly && target->GetTypeId() != TYPEID_PLAYER)
        return false;

    if(dist && !me->IsWithinCombatRange(target, dist))
        return false;

    if(aura)
    {
        if(aura > 0)
        {
            if(!target->HasAura(aura))
                return false;
        }
        else
        {
            if(target->HasAura(aura))
                return false;
        }
    }

    return true;
}

struct TargetDistanceOrder : public std::binary_function<const Unit *, const Unit *, bool>
{
    const Unit * me;
    TargetDistanceOrder(const Unit* Target) : me(Target) {};
    // functor for operator ">"
    bool operator()(const Unit * _Left, const Unit * _Right) const
    {
        return (me->GetDistanceSq(_Left) < me->GetDistanceSq(_Right));
    }
};

Unit* UnitAI::SelectTarget(SelectAggroTarget targetType, uint32 position, float dist, bool playerOnly, int32 aura)
{
    if(targetType == SELECT_TARGET_NEAREST || targetType == SELECT_TARGET_FARTHEST)
    {
        std::list<HostilReference*> &m_threatlist = me->getThreatManager().getThreatList();
        if(position >= m_threatlist.size())
            return NULL;

        std::list<Unit*> targetList;
        for(std::list<HostilReference*>::iterator itr = m_threatlist.begin(); itr!= m_threatlist.end(); ++itr)
            if(SelectTargetHelper(me, (*itr)->getTarget(), playerOnly, dist, aura))
                targetList.push_back((*itr)->getTarget());

        if(position >= targetList.size())
            return NULL;

        targetList.sort(TargetDistanceOrder(me));

        if(targetType == SELECT_TARGET_NEAREST)
        {
            std::list<Unit*>::iterator i = targetList.begin();
            advance(i, position);
            return *i;
        }
        else
        {
            std::list<Unit*>::reverse_iterator i = targetList.rbegin();
            advance(i, position);
            return *i;
        }
    }
    else
    {
        std::list<HostilReference*> m_threatlist = me->getThreatManager().getThreatList();
        std::list<HostilReference*>::iterator i;
        while(position < m_threatlist.size())
        {
            if(targetType == SELECT_TARGET_BOTTOMAGGRO)
            {
                i = m_threatlist.end();
                advance(i, - (int32)position - 1);
            }
            else
            {
                i = m_threatlist.begin();
                if(targetType == SELECT_TARGET_TOPAGGRO)
                    advance(i, position);
                else // random
                    advance(i, position + rand()%(m_threatlist.size() - position));
            }

            if(SelectTargetHelper(me, (*i)->getTarget(), playerOnly, dist, aura))
                return (*i)->getTarget();
            else
                m_threatlist.erase(i);
        }
    }

    return NULL;
}

void UnitAI::SelectTargetList(std::list<Unit*> &targetList, uint32 num, SelectAggroTarget targetType, float dist, bool playerOnly, int32 aura)
{
    if(targetType == SELECT_TARGET_NEAREST || targetType == SELECT_TARGET_FARTHEST)
    {
        std::list<HostilReference*> &m_threatlist = me->getThreatManager().getThreatList();
        if(m_threatlist.empty())
            return;

        for(std::list<HostilReference*>::iterator itr = m_threatlist.begin(); itr!= m_threatlist.end(); ++itr)
            if(SelectTargetHelper(me, (*itr)->getTarget(), playerOnly, dist, aura))
                targetList.push_back((*itr)->getTarget());

        targetList.sort(TargetDistanceOrder(me));
        targetList.resize(num);
        if(targetType == SELECT_TARGET_FARTHEST)
            targetList.reverse();
    }
    else
    {
        std::list<HostilReference*> m_threatlist = me->getThreatManager().getThreatList();
        std::list<HostilReference*>::iterator i;
        while(!m_threatlist.empty() && num)
        {
            if(targetType == SELECT_TARGET_BOTTOMAGGRO)
            {
                i = m_threatlist.end();
                --i;
            }
            else
            {
                i = m_threatlist.begin();
                if(targetType == SELECT_TARGET_RANDOM)
                    advance(i, rand()%m_threatlist.size());
            }

            if(SelectTargetHelper(me, (*i)->getTarget(), playerOnly, dist, aura))
            {
                targetList.push_back((*i)->getTarget());
                --num;
            }
            m_threatlist.erase(i);
        }
    }
}

void UnitAI::DoCast(uint32 spellId)
{
    Unit *target = NULL;
    //sLog.outError("aggre %u %u", spellId, (uint32)AISpellInfo[spellId].target);
    switch(AISpellInfo[spellId].target)
    {
        default:
        case AITARGET_SELF:     target = me; break;
        case AITARGET_VICTIM:   target = me->getVictim(); break;
        case AITARGET_ENEMY:
        {
            const SpellEntry * spellInfo = GetSpellStore()->LookupEntry(spellId);
            bool playerOnly = spellInfo->AttributesEx3 & SPELL_ATTR_EX3_PLAYERS_ONLY;
            float range = GetSpellMaxRange(spellInfo, false);
            target = SelectTarget(SELECT_TARGET_RANDOM, 0, GetSpellMaxRange(spellInfo, false), playerOnly);
            break;
        }
        case AITARGET_ALLY:     target = me; break;
        case AITARGET_BUFF:     target = me; break;
        case AITARGET_DEBUFF:
        {
            const SpellEntry * spellInfo = GetSpellStore()->LookupEntry(spellId);
            bool playerOnly = spellInfo->AttributesEx3 & SPELL_ATTR_EX3_PLAYERS_ONLY;
            float range = GetSpellMaxRange(spellInfo, false);
            if(!(spellInfo->Attributes & SPELL_ATTR_BREAKABLE_BY_DAMAGE)
                && !(spellInfo->AuraInterruptFlags & AURA_INTERRUPT_FLAG_NOT_VICTIM)
                && SelectTargetHelper(me, me->getVictim(), playerOnly, range, -(int32)spellId))
                target = me->getVictim();
            else
                target = SelectTarget(SELECT_TARGET_RANDOM, 0, range, playerOnly, -(int32)spellId);
            break;
        }
    }

    if(target)
        me->CastSpell(target, spellId, false);
}

void UnitAI::DoCast(Unit* victim, uint32 spellId, bool triggered)
{
    if(!victim || me->hasUnitState(UNIT_STAT_CASTING) && !triggered)
        return;

    me->CastSpell(victim, spellId, triggered);
}

void UnitAI::DoCastAOE(uint32 spellId, bool triggered)
{
    if(!triggered && me->hasUnitState(UNIT_STAT_CASTING))
        return;

    me->CastSpell((Unit*)NULL, spellId, triggered);
}

#define UPDATE_TARGET(a) {if(AIInfo->target<a) AIInfo->target=a;}

void UnitAI::FillAISpellInfo()
{
    AISpellInfo = new AISpellInfoType[GetSpellStore()->GetNumRows()];

    AISpellInfoType *AIInfo = AISpellInfo;
    const SpellEntry * spellInfo;

    for(uint32 i = 0; i < GetSpellStore()->GetNumRows(); ++i, ++AIInfo)
    {
        spellInfo = GetSpellStore()->LookupEntry(i);
        if(!spellInfo)
            continue;

        if(spellInfo->Attributes & SPELL_ATTR_CASTABLE_WHILE_DEAD)
            AIInfo->condition = AICOND_DIE;
        else if(IsPassiveSpell(i) || GetSpellDuration(spellInfo) == -1)
            AIInfo->condition = AICOND_AGGRO;
        else
            AIInfo->condition = AICOND_COMBAT;

        if(AIInfo->cooldown < spellInfo->RecoveryTime)
            AIInfo->cooldown = spellInfo->RecoveryTime;

        if(!GetSpellMaxRange(spellInfo, false))
            UPDATE_TARGET(AITARGET_SELF)
        else
        {
            for(uint32 j = 0; j < 3; ++j)
            {
                uint32 targetType = spellInfo->EffectImplicitTargetA[j];

                if(targetType == TARGET_UNIT_TARGET_ENEMY
                    || targetType == TARGET_DST_TARGET_ENEMY)
                    UPDATE_TARGET(AITARGET_VICTIM)
                else if(targetType == TARGET_UNIT_AREA_ENEMY_DST)
                    UPDATE_TARGET(AITARGET_ENEMY)

                if(spellInfo->Effect[j] == SPELL_EFFECT_APPLY_AURA)
                {
                    if(targetType == TARGET_UNIT_TARGET_ENEMY)
                        UPDATE_TARGET(AITARGET_DEBUFF)
                    else if(IsPositiveSpell(i))
                        UPDATE_TARGET(AITARGET_BUFF)
                }
            }
        }
    }
}

//Enable PlayerAI when charmed
void PlayerAI::OnCharmed(bool apply) { me->IsAIEnabled = apply; }

void SimpleCharmedAI::UpdateAI(const uint32 /*diff*/)
{
    Creature *charmer = (Creature*)me->GetCharmer();

    //kill self if charm aura has infinite duration
    if(charmer->IsInEvadeMode())
    {
        Unit::AuraEffectList const& auras = me->GetAurasByType(SPELL_AURA_MOD_CHARM);
        for(Unit::AuraEffectList::const_iterator iter = auras.begin(); iter != auras.end(); ++iter)
            if((*iter)->GetCasterGUID() == charmer->GetGUID() && (*iter)->GetParentAura()->IsPermanent())
            {
                charmer->Kill(me);
                return;
            }
    }

    if(!charmer->isInCombat())
        me->GetMotionMaster()->MoveFollow(charmer, PET_FOLLOW_DIST, PET_FOLLOW_ANGLE);

    Unit *target = me->getVictim();
    if(!target || !charmer->canAttack(target))
        AttackStart(charmer->SelectNearestTarget());
}