bool Unit::IsImmunedToSpell(SpellInfo const* spellInfo)
{
    if (!spellInfo)
        return false;

    // Single spell immunity.
    SpellImmuneList const& idList = m_spellImmune[IMMUNITY_ID];
    for (SpellImmuneList::const_iterator itr = idList.begin(); itr != idList.end(); ++itr)
        if (itr->type == spellInfo->Id)
            return true;

    if (spellInfo->Attributes & SPELL_ATTR0_UNAFFECTED_BY_INVULNERABILITY)
        return false;

    if (spellInfo->Dispel)
    {
        SpellImmuneList const& dispelList = m_spellImmune[IMMUNITY_DISPEL];
        for (SpellImmuneList::const_iterator itr = dispelList.begin(); itr != dispelList.end(); ++itr)
            if (itr->type == spellInfo->Dispel)
                return true;
    }

    // Spells that don't have effectMechanics.
    if (!spellInfo->HasAnyEffectMechanic() && spellInfo->Mechanic)
    {
        SpellImmuneList const& mechanicList = m_spellImmune[IMMUNITY_MECHANIC];
        for (SpellImmuneList::const_iterator itr = mechanicList.begin(); itr != mechanicList.end(); ++itr)
            if (itr->type == spellInfo->Mechanic)
                return true;
    }

    bool immuneToAllEffects = true;
    for (uint8 i = 0; i < MAX_SPELL_EFFECTS; ++i)
    {
        // State/effect immunities applied by aura expect full spell immunity
        // Ignore effects with mechanic, they are supposed to be checked separately
        if (spellInfo->Effects[i].Mechanic || !IsImmunedToSpellEffect(spellInfo, i))
        {
            immuneToAllEffects = false;
            break;
        }
    }
    if (immuneToAllEffects) //Return immune only if the target is immune to all spell effects.
        return true;

    if (spellInfo->Id != 42292 && spellInfo->Id !=59752)
    {
        SpellImmuneList const& schoolList = m_spellImmune[IMMUNITY_SCHOOL];
        for (SpellImmuneList::const_iterator itr = schoolList.begin(); itr != schoolList.end(); ++itr)
        {
            SpellInfo const* immuneSpellInfo = sSpellMgr->GetSpellInfo(itr->spellId);
            if ((itr->type & spellInfo->GetSchoolMask())
                && !(immuneSpellInfo && immuneSpellInfo->IsPositive() && spellInfo->IsPositive())
                && !spellInfo->CanPierceImmuneAura(immuneSpellInfo))
                return true;
        }
    }

    return false;
}

bool Unit::IsImmunedToSpellEffect(SpellInfo const* spellInfo, uint32 index) const
{
    if (!spellInfo)
        return false;
    // If m_immuneToEffect type contain this effect type, IMMUNE effect.
    uint32 effect = spellInfo->Effects[index].Effect;
    SpellImmuneList const& effectList = m_spellImmune[IMMUNITY_EFFECT];
    for (SpellImmuneList::const_iterator itr = effectList.begin(); itr != effectList.end(); ++itr)
        if (itr->type == effect)
            return true;

    if (uint32 mechanic = spellInfo->Effects[index].Mechanic)
    {
        SpellImmuneList const& mechanicList = m_spellImmune[IMMUNITY_MECHANIC];
        for (SpellImmuneList::const_iterator itr = mechanicList.begin(); itr != mechanicList.end(); ++itr)
            if (itr->type == mechanic)
                return true;
    }

    if (uint32 aura = spellInfo->Effects[index].ApplyAuraName)
    {
        SpellImmuneList const& list = m_spellImmune[IMMUNITY_STATE];
        for (SpellImmuneList::const_iterator itr = list.begin(); itr != list.end(); ++itr)
            if (itr->type == aura)
                return true;
        // Check for immune to application of harmful magical effects
        AuraEffectList const& immuneAuraApply = GetAuraEffectsByType(SPELL_AURA_MOD_IMMUNE_AURA_APPLY_SCHOOL);
        for (AuraEffectList::const_iterator iter = immuneAuraApply.begin(); iter != immuneAuraApply.end(); ++iter)
            if ((spellInfo->Dispel == DISPEL_MAGIC || spellInfo->Dispel == DISPEL_CURSE || spellInfo->Dispel == DISPEL_POISON || spellInfo->Dispel == DISPEL_DISEASE || spellInfo->Mechanic == MECHANIC_BANISH) &&                                      // Magic debuff
                ((*iter)->GetMiscValue() & spellInfo->GetSchoolMask()) &&  // Check school
                !spellInfo->IsPositiveEffect(index))                                  // Harmful
                return true;
    }

    return false;
}