[Core/Unit] Fix a crash by taken damage. (#379)

src/server/game/AI/CreatureAI.h

@@ -1,5 +1,5 @@
 /*
-* This file is part of the Pandaria 5.4.8 Project. See THANKS file for Copyright information
+* This file is part of the Legends of Azeroth Pandaria Project. See THANKS 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
@@ -80,13 +80,23 @@ class TC_GAME_API CreatureAI : public UnitAI
         Creature* DoSummonFlyer(uint32 entry, WorldObject* obj, float flightZ, float radius = 5.0f, uint32 despawnTime = 30000, TempSummonType summonType = TEMPSUMMON_CORPSE_TIMED_DESPAWN);
 
     public:
-        void Talk(uint8 id, WorldObject const* whisperTarget = nullptr);
-        void TalkToMap(uint8 id, WorldObject const* whisperTarget = nullptr);
+        // EnumUtils: DESCRIBE THIS (in CreatureAI::)
+        enum EvadeReason
+        {
+            EVADE_REASON_NO_HOSTILES,       // the creature's threat list is empty
+            EVADE_REASON_BOUNDARY,          // the creature has moved outside its evade boundary
+            EVADE_REASON_NO_PATH,           // the creature was unable to reach its target for over 5 seconds
+            EVADE_REASON_SEQUENCE_BREAK,    // this is a boss and the pre-requisite encounters for engaging it are not defeated yet
+            EVADE_REASON_OTHER,             // anything else
+        };
 
         explicit CreatureAI(Creature* creature);
 
         virtual ~CreatureAI();
 
+        void Talk(uint8 id, WorldObject const* whisperTarget = nullptr);
+        void TalkToMap(uint8 id, WorldObject const* whisperTarget = nullptr);
+
         /// == Reactions At =================================
 
         // Called if IsVisible(Unit* who) is true at each who move, reaction at visibility zone enter

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

@@ -213,7 +213,7 @@ lootForPickPocketed(false), lootForBody(false), m_groupLootTimer(0), lootingGrou
 m_PlayerDamageReq(0), m_lootRecipient(), m_lootRecipientGroup(0), m_corpseRemoveTime(0), m_respawnTime(0),
 m_respawnDelay(300), m_corpseDelay(60), m_wanderDistance(0.0f), m_WalkMode(0.0f), 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_AI_locked(false), m_meleeDamageSchoolMask(SPELL_SCHOOL_MASK_NORMAL),
+m_AlreadySearchedAssistance(false), m_cannotReachTarget(false), m_cannotReachTimer(0), m_regenHealth(true), m_AI_locked(false), m_meleeDamageSchoolMask(SPELL_SCHOOL_MASK_NORMAL),
 m_creatureInfo(nullptr), m_creatureData(nullptr), m_path_id(0), m_formation(nullptr), m_triggerJustAppeared(false), m_respawnDelayMax(0), dynamicHealthPlayersCount(0)
 {
     m_regenTimer = 0;
@@ -682,6 +682,15 @@ void Creature::Update(uint32 diff)
             m_regenTimer += diff;
 
             Regenerate();
+
+            if (CanNotReachTarget() && !IsInEvadeMode() && !GetMap()->IsRaid())
+            {
+                m_cannotReachTimer += diff;
+                if (m_cannotReachTimer >= CREATURE_NOPATH_EVADE_TIME)
+                    if (CreatureAI* ai = AI())
+                        ai->EnterEvadeMode(); // TODO missing EVADE_REASON
+                        // ai->EnterEvadeMode(CreatureAI::EVADE_REASON_NO_PATH);
+            }            
             break;
         }
         default:
@@ -2737,6 +2746,18 @@ uint32 Creature::GetPetAutoSpellOnPos(uint8 pos) const
         return m_charmInfo->GetCharmSpell(pos)->GetAction();
 }
 
+void Creature::SetCannotReachTarget(bool cannotReach)
+{
+    if (cannotReach == m_cannotReachTarget)
+        return;
+    m_cannotReachTarget = cannotReach;
+    m_cannotReachTimer = 0;
+
+    if (cannotReach)
+        TC_LOG_DEBUG("entities.unit.chase", "Creature::SetCannotReachTarget() called with true");
+        // TC_LOG_DEBUG("entities.unit.chase", "Creature::SetCannotReachTarget() called with true. Details: s%", GetDebugInfo()); // TODO GetDebugInfo missing
+}
+
 void Creature::SetPosition(float x, float y, float z, float o)
 {
     // prevent crash when a bad coord is sent by the client

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

@@ -308,6 +308,7 @@ class TC_GAME_API Creature : public Unit, public GridObject<Creature>, public Ma
         uint8 GetLevelForTarget(WorldObject const* target) const override; // overwrite Unit::getLevelForTarget for boss level support
 
         bool IsInEvadeMode() const { return HasUnitState(UNIT_STATE_EVADE); }
+        bool IsEvadingAttacks() const { return IsInEvadeMode() || CanNotReachTarget(); }
 
         bool AIM_Initialize(CreatureAI* ai = NULL);
         void Motion_Initialize();
@@ -493,6 +494,9 @@ class TC_GAME_API Creature : public Unit, public GridObject<Creature>, public Ma
         virtual uint8 GetPetAutoSpellSize() const { return MAX_SPELL_CHARM; }
         virtual uint32 GetPetAutoSpellOnPos(uint8 pos) const;
 
+        void SetCannotReachTarget(bool cannotReach);
+        bool CanNotReachTarget() const { return m_cannotReachTarget; }
+
         void SetPosition(float x, float y, float z, float o);
         void SetPosition(const Position &pos) { SetPosition(pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ(), pos.GetOrientation()); }
 
@@ -592,6 +596,9 @@ class TC_GAME_API Creature : public Unit, public GridObject<Creature>, public Ma
 
         bool m_AlreadyCallAssistance;
         bool m_AlreadySearchedAssistance;
+        bool m_cannotReachTarget;
+        uint32 m_cannotReachTimer;
+
         bool m_regenHealth;
         bool m_regenMana = true;
         bool m_AI_locked;

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

@@ -127,10 +127,14 @@ struct TC_GAME_API CreatureMovementData
     std::string ToString() const;
 };
 
-static uint8 const MAX_KILL_CREDIT = 2;
-static uint32 const MAX_CREATURE_MODELS = 4;
-static uint32 const MAX_CREATURE_QUEST_ITEMS = 6;
-static uint32 const MAX_CREATURE_SPELLS = 8;
+static const uint32 CREATURE_REGEN_INTERVAL = 2 * IN_MILLISECONDS;
+static const uint32 PET_FOCUS_REGEN_INTERVAL = 4 * IN_MILLISECONDS;
+static const uint32 CREATURE_NOPATH_EVADE_TIME = 5 * IN_MILLISECONDS;
+
+static const uint8 MAX_KILL_CREDIT = 2;
+static const uint32 MAX_CREATURE_MODELS = 4;
+static const uint32 MAX_CREATURE_QUEST_ITEMS = 6;
+static const uint32 MAX_CREATURE_SPELLS = 8;
 
 struct CreatureModel
 {

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

@@ -1638,7 +1638,12 @@ void Unit::DealMeleeDamage(CalcDamageInfo* damageInfo, bool durabilityLoss)
 {
     Unit* victim = damageInfo->target;
 
-    if (!victim->IsAlive() || victim->HasUnitState(UNIT_STATE_IN_FLIGHT) || (victim->GetTypeId() == TYPEID_UNIT && victim->ToCreature()->IsInEvadeMode()))
+    auto canTakeMeleeDamage = [&]()
+    {
+        return victim->IsAlive() && !victim->HasUnitState(UNIT_STATE_IN_FLIGHT) && (victim->GetTypeId() != TYPEID_UNIT || !victim->ToCreature()->IsEvadingAttacks());
+    };
+
+    if (!canTakeMeleeDamage())
         return;
 
     // Hmmmm dont like this emotes client must by self do all animations
@@ -1679,9 +1684,17 @@ void Unit::DealMeleeDamage(CalcDamageInfo* damageInfo, bool durabilityLoss)
         }
     }
 
-    // Call default DealDamage
-    CleanDamage cleanDamage(damageInfo->cleanDamage, damageInfo->absorb, damageInfo->attackType, damageInfo->hitOutCome);
-    DealDamage(victim, damageInfo->damage, &cleanDamage, DIRECT_DAMAGE, SpellSchoolMask(damageInfo->damageSchoolMask), NULL, durabilityLoss);
+    // TODO multi damageschool
+    if (!canTakeMeleeDamage() || (!damageInfo->damage && !damageInfo->absorb && !damageInfo->resist)) 
+    {
+
+    }
+    else
+    {
+        // Call default DealDamage
+        CleanDamage cleanDamage(damageInfo->cleanDamage, damageInfo->absorb, damageInfo->attackType, damageInfo->hitOutCome);
+        DealDamage(victim, damageInfo->damage, &cleanDamage, DIRECT_DAMAGE, SpellSchoolMask(damageInfo->damageSchoolMask), nullptr, durabilityLoss);        
+    }
 
     // If this is a creature and it attacks from behind it has a probability to daze it's victim
     if ((damageInfo->hitOutCome == MELEE_HIT_CRIT || damageInfo->hitOutCome == MELEE_HIT_CRUSHING || damageInfo->hitOutCome == MELEE_HIT_NORMAL || damageInfo->hitOutCome == MELEE_HIT_GLANCING) &&