fix(Core/AI): Improve creature leashing behavior. (#19751)

* Init.

https: //github.com/vmangos/core/commit/7d2f1e2923734ea1b983eeaa0208cfd158d4af02
Co-Authored-By: ratkosrb <35845488+ratkosrb@users.noreply.github.com>

* Hackfix for pets.

* Whoops.

* Correct evade uses.

* Conflict.

* Actually fix grace timer.

* Add visibility distance check.

Creatures should always fail combat checks in the open world if they're outside of visibility distance, might not be the case for worldbosses.

---------

Co-authored-by: ratkosrb <35845488+ratkosrb@users.noreply.github.com>

src/server/game/AI/CreatureAI.cpp

@@ -307,7 +307,7 @@ bool CreatureAI::_EnterEvadeMode(EvadeReason /*why*/)
     me->LoadCreaturesAddon(true);
     me->SetLootRecipient(nullptr);
     me->ResetPlayerDamageReq();
-    me->SetLastDamagedTime(0);
+    me->ClearLastLeashExtensionTimePtr();
     me->SetCannotReachTarget();
 
     if (ZoneScript* zoneScript = me->GetZoneScript() ? me->GetZoneScript() : (ZoneScript*)me->GetInstanceScript())

src/server/game/Entities/Creature/Creature.cpp

@@ -220,9 +220,6 @@ bool AssistDelayEvent::Execute(uint64 /*e_time*/, uint32 /*p_time*/)
 {
     if (Unit* victim = ObjectAccessor::GetUnit(*m_owner, m_victim))
     {
-        // Initialize last damage timer if it doesn't exist
-        m_owner->SetLastDamagedTime(GameTime::GetGameTime().count() + MAX_AGGRO_RESET_TIME);
-
         while (!m_assistants.empty())
         {
             Creature* assistant = ObjectAccessor::GetCreature(*m_owner, *m_assistants.begin());
@@ -233,9 +230,14 @@ bool AssistDelayEvent::Execute(uint64 /*e_time*/, uint32 /*p_time*/)
                 assistant->SetNoCallAssistance(true);
                 assistant->CombatStart(victim);
                 if (assistant->IsAIEnabled)
+                {
                     assistant->AI()->AttackStart(victim);
 
-                assistant->SetLastDamagedTimePtr(m_owner->GetLastDamagedTimePtr());
+                    // When nearby mobs aggro from another mob's initial call for assistance
+                    // their leash timers become linked and attacking one will keep the rest from evading.
+                    if (assistant->GetVictim())
+                        assistant->SetLastLeashExtensionTimePtr(m_owner->GetLastLeashExtensionTimePtr());
+                }
             }
         }
     }
@@ -272,7 +274,7 @@ Creature::Creature(bool isWorldObject): Unit(isWorldObject), MovableMapObject(),
     m_transportCheckTimer(1000), lootPickPocketRestoreTime(0), m_combatPulseTime(0), m_combatPulseDelay(0), m_reactState(REACT_AGGRESSIVE), m_defaultMovementType(IDLE_MOTION_TYPE),
     m_spawnId(0), m_equipmentId(0), m_originalEquipmentId(0), m_AlreadyCallAssistance(false),
     m_AlreadySearchedAssistance(false), m_regenHealth(true), m_regenPower(true), m_AI_locked(false), m_meleeDamageSchoolMask(SPELL_SCHOOL_MASK_NORMAL), m_originalEntry(0), m_moveInLineOfSightDisabled(false), m_moveInLineOfSightStrictlyDisabled(false),
-    m_homePosition(), m_transportHomePosition(), m_creatureInfo(nullptr), m_creatureData(nullptr), m_detectionDistance(20.0f), m_waypointID(0), m_path_id(0), m_formation(nullptr), _lastDamagedTime(nullptr), m_cannotReachTimer(0),
+    m_homePosition(), m_transportHomePosition(), m_creatureInfo(nullptr), m_creatureData(nullptr), m_detectionDistance(20.0f), m_waypointID(0), m_path_id(0), m_formation(nullptr), m_lastLeashExtensionTime(nullptr), m_cannotReachTimer(0),
     _isMissingSwimmingFlagOutOfCombat(false), m_assistanceTimer(0), _playerDamageReq(0), _damagedByPlayer(false), _isCombatMovementAllowed(true)
 {
     m_regenTimer = CREATURE_REGEN_INTERVAL;
@@ -1961,8 +1963,6 @@ void Creature::setDeathState(DeathState state, bool despawn)
 
     if (state == DeathState::JustDied)
     {
-        _lastDamagedTime.reset();
-
         m_corpseRemoveTime = GameTime::GetGameTime().count() + m_corpseDelay;
         m_respawnTime = GameTime::GetGameTime().count() + m_respawnDelay + m_corpseDelay;
 
@@ -2640,7 +2640,7 @@ bool Creature::CanCreatureAttack(Unit const* victim, bool skipDistCheck) const
         return false;
 
     // cannot attack if is during 5 second grace period, unless being attacked
-    if (m_respawnedTime && (GameTime::GetGameTime().count() - m_respawnedTime) < 5 && !GetLastDamagedTime())
+    if (m_respawnedTime && (GameTime::GetGameTime().count() - m_respawnedTime) < 5 && !IsEngagedBy(victim))
     {
         return false;
     }
@@ -2656,9 +2656,15 @@ bool Creature::CanCreatureAttack(Unit const* victim, bool skipDistCheck) const
         if (GetMap()->IsDungeon())
             return true;
 
+        float visibility = std::max<float>(GetVisibilityRange(), victim->GetVisibilityRange());
+
+        // if outside visibility
+        if (!IsWithinDist(victim, visibility))
+            return false;
+
         // pussywizard: don't check distance to home position if recently damaged (allow kiting away from spawnpoint!)
         // xinef: this should include taunt auras
-        if (!isWorldBoss() && (GetLastDamagedTime() > GameTime::GetGameTime().count() || HasAuraType(SPELL_AURA_MOD_TAUNT)))
+        if (!isWorldBoss() && (GetLastLeashExtensionTime() + 12 > GameTime::GetGameTime().count() || HasAuraType(SPELL_AURA_MOD_TAUNT)))
             return true;
     }
 
@@ -2666,10 +2672,13 @@ bool Creature::CanCreatureAttack(Unit const* victim, bool skipDistCheck) const
         return true;
 
     // xinef: added size factor for huge npcs
-    float dist = std::min<float>(GetMap()->GetVisibilityRange() + GetObjectSize() * 2, 150.0f);
+    float dist = std::min<float>(GetDetectionRange() + GetObjectSize() * 2, 150.0f);
 
     if (Unit* unit = GetCharmerOrOwner())
+    {
+        dist = std::min<float>(GetMap()->GetVisibilityRange() + GetObjectSize() * 2, 150.0f);
         return victim->IsWithinDist(unit, dist);
+    }
     else
     {
         // to prevent creatures in air ignore attacks because distance is already too high...
@@ -3666,35 +3675,31 @@ bool Creature::IsNotReachableAndNeedRegen() const
     return false;
 }
 
-time_t Creature::GetLastDamagedTime() const
+std::shared_ptr<time_t> const& Creature::GetLastLeashExtensionTimePtr() const
 {
-    if (!_lastDamagedTime)
+    if (m_lastLeashExtensionTime == nullptr)
-        return time_t(0);
+        m_lastLeashExtensionTime = std::make_shared<time_t>(time(nullptr));
-
+    return m_lastLeashExtensionTime;
-    return *_lastDamagedTime;
 }
 
-std::shared_ptr<time_t> const& Creature::GetLastDamagedTimePtr() const
+void Creature::SetLastLeashExtensionTimePtr(std::shared_ptr<time_t> const& timer)
 {
-    return _lastDamagedTime;
+    m_lastLeashExtensionTime = timer;
 }
 
-void Creature::SetLastDamagedTime(time_t val)
+void Creature::ClearLastLeashExtensionTimePtr()
 {
-    if (val > 0)
+    m_lastLeashExtensionTime.reset();
-    {
-        if (_lastDamagedTime)
-            *_lastDamagedTime = val;
-        else
-            _lastDamagedTime = std::make_shared<time_t>(val);
-    }
-    else
-        _lastDamagedTime.reset();
 }
 
-void Creature::SetLastDamagedTimePtr(std::shared_ptr<time_t> const& val)
+time_t Creature::GetLastLeashExtensionTime() const
 {
-    _lastDamagedTime = val;
+    return *GetLastLeashExtensionTimePtr();
+}
+
+void Creature::UpdateLeashExtensionTime()
+{
+    (*GetLastLeashExtensionTimePtr()) = time(nullptr);
 }
 
 bool Creature::CanPeriodicallyCallForAssistance() const

src/server/game/Entities/Creature/Creature.h

@@ -381,10 +381,11 @@ public:
     [[nodiscard]] bool IsMovementPreventedByCasting() const override;
 
     // Part of Evade mechanics
-    [[nodiscard]] time_t GetLastDamagedTime() const;
+    std::shared_ptr<time_t> const& GetLastLeashExtensionTimePtr() const;
-    [[nodiscard]] std::shared_ptr<time_t> const& GetLastDamagedTimePtr() const;
+    void SetLastLeashExtensionTimePtr(std::shared_ptr<time_t> const& timer);
-    void SetLastDamagedTime(time_t val);
+    void ClearLastLeashExtensionTimePtr();
-    void SetLastDamagedTimePtr(std::shared_ptr<time_t> const& val);
+    time_t GetLastLeashExtensionTime() const;
+    void UpdateLeashExtensionTime();
 
     bool IsFreeToMove();
     static constexpr uint32 MOVE_CIRCLE_CHECK_INTERVAL = 3000;
@@ -500,7 +501,9 @@ private:
     CreatureGroup* m_formation;
     bool TriggerJustRespawned;
 
-    mutable std::shared_ptr<time_t> _lastDamagedTime; // Part of Evade mechanics
+    // Shared timer between mobs who assist another.
+    // Damaging one extends leash range on all of them.
+    mutable std::shared_ptr<time_t> m_lastLeashExtensionTime;
 
     ObjectGuid m_cannotReachTarget;
     uint32 m_cannotReachTimer;

src/server/game/Entities/Unit/Unit.cpp

@@ -1041,10 +1041,6 @@ uint32 Unit::DealDamage(Unit* attacker, Unit* victim, uint32 damage, CleanDamage
 
         if (!victim->IsPlayer())
         {
-            // Part of Evade mechanics. DoT's and Thorns / Retribution Aura do not contribute to this
-            if (damagetype != DOT && damage > 0 && !victim->GetOwnerGUID().IsPlayer() && (!spellProto || !spellProto->HasAura(SPELL_AURA_DAMAGE_SHIELD)))
-                victim->ToCreature()->SetLastDamagedTime(GameTime::GetGameTime().count() + MAX_AGGRO_RESET_TIME);
-
             if (attacker)
             {
                 if (spellProto && victim->CanHaveThreatList() && !victim->HasUnitState(UNIT_STATE_EVADE) && !victim->IsInCombatWith(attacker))
@@ -10387,6 +10383,8 @@ void Unit::CombatStop(bool includingCast)
     RemoveAllAttackers();
     if (IsPlayer())
         ToPlayer()->SendAttackSwingCancelAttack();     // melee and ranged forced attack cancel
+    if (Creature* pCreature = ToCreature())
+        pCreature->ClearLastLeashExtensionTimePtr();
     ClearInCombat();
 
     // xinef: just in case
@@ -13539,6 +13537,9 @@ void Unit::SetInCombatWith(Unit* enemy, uint32 duration)
             return;
         }
     }
+    if (Creature* pCreature = ToCreature())
+        pCreature->UpdateLeashExtensionTime();
+
     SetInCombatState(false, enemy, duration);
 }
 

src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.cpp

@@ -148,6 +148,15 @@ bool ChaseMovementGenerator<T>::DoUpdate(T* owner, uint32 time_diff)
         owner->ClearUnitState(UNIT_STATE_CHASE_MOVE);
         owner->SetInFront(target);
         MovementInform(owner);
+
+        // Mobs should chase you infinitely if you stop and wait every few seconds.
+        i_leashExtensionTimer.Update(time_diff);
+        if (i_leashExtensionTimer.Passed())
+        {
+            i_leashExtensionTimer.Reset(5000);
+            if (Creature* creature = owner->ToCreature())
+                creature->UpdateLeashExtensionTime();
+        }
     }
 
     // if the target moved, we have to consider whether to adjust

src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.h

@@ -39,7 +39,7 @@ class ChaseMovementGenerator : public MovementGeneratorMedium<T, ChaseMovementGe
 {
 public:
     ChaseMovementGenerator(Unit* target, Optional<ChaseRange> range = {}, Optional<ChaseAngle> angle = {})
-        : TargetedMovementGeneratorBase(target), i_path(nullptr), i_recheckDistance(0), i_recalculateTravel(true), _range(range), _angle(angle) {}
+        : TargetedMovementGeneratorBase(target), i_leashExtensionTimer(0), i_path(nullptr), i_recheckDistance(0), i_recalculateTravel(true), _range(range), _angle(angle) {}
     ~ChaseMovementGenerator() { }
 
     MovementGeneratorType GetMovementGeneratorType() { return CHASE_MOTION_TYPE; }
@@ -59,6 +59,7 @@ public:
     bool HasLostTarget(Unit* unit) const { return unit->GetVictim() != this->GetTarget(); }
 
 private:
+    TimeTrackerSmall i_leashExtensionTimer;
     std::unique_ptr<PathGenerator> i_path;
     TimeTrackerSmall i_recheckDistance;
     bool i_recalculateTravel;

src/server/scripts/Northrend/FrozenHalls/PitOfSaron/pit_of_saron.cpp

@@ -1130,7 +1130,7 @@ public:
             me->LoadCreaturesAddon(true);
             me->SetLootRecipient(nullptr);
             me->ResetPlayerDamageReq();
-            me->SetLastDamagedTime(0);
+            me->UpdateLeashExtensionTime();
         }
     };
 

src/server/scripts/Pet/pet_hunter.cpp

@@ -58,7 +58,7 @@ struct npc_pet_hunter_snake_trap : public ScriptedAI
         me->LoadCreaturesAddon(true);
         me->SetLootRecipient(nullptr);
         me->ResetPlayerDamageReq();
-        me->SetLastDamagedTime(0);
+        me->ClearLastLeashExtensionTimePtr();
 
         me->AddUnitState(UNIT_STATE_EVADE);
         me->GetMotionMaster()->MoveTargetedHome();