Core/Creatures: Various fixes for creatures, regarding combat conditions, despawning, and few others (#18998)

* Made some changes to kiting mechanics, simplified code and made taunt auras prolong combat no matter the distance from the spawn
Unified some creature despawning code, removed some brutal direct calls in scripts
Don't play death anim on forced despawn
Removed some redundant visibility changes on creature despawn
Fixed possible problem with pet initializing template info from difficulty greater than normal
Properly keep UNIT_FLAG_IN_COMBAT on UpdateEntry call
Moved RegenerateMana function to general Regenerate(Power) function
Fixed increased health regeneration from polymorph for pets
Implemented CREATURE_TYPE_FLAG_GHOST_VISIBLE, those creatures will be properly seen when player is dead also
Removed hackfix from Gaeriyan and Franclorn Forgewright, fixed properly
Simplified ForcedRespawnTime code in ForcedDespawn
Do not allow to assist unit while evading or when enemy is evading
Do not allow to attack other units when evading or when the unit is evading
Corrected distance checking code before creature is allowed to evade, should fix some common problems
Properly return summon position for summoned creatures as their respawn position
Properly stop all moving units on gossip hello, no matter their npc flags

(cherrypicked from e1f14215d86fc9f0cd041f0e87bf0a689c086329)

22 files changed, 69 insertions, 63 deletions

diff --git a/src/server/scripts/Commands/cs_pet.cpp b/src/server/scripts/Commands/cs_pet.cpp
index 37484bba405..9ae7ddd02b1 100644
--- a/src/server/scripts/Commands/cs_pet.cpp
+++ b/src/server/scripts/Commands/cs_pet.cpp
@@ -98,8 +98,7 @@ public:
             return false;
         }
 
-        creatureTarget->setDeathState(JUST_DIED);
-        creatureTarget->RemoveCorpse();
+        creatureTarget->DespawnOrUnsummon();
         creatureTarget->SetHealth(0); // just for nice GM-mode view
 
         pet->SetCreatorGUID(player->GetGUID());
diff --git a/src/server/scripts/EasternKingdoms/Gnomeregan/gnomeregan.cpp b/src/server/scripts/EasternKingdoms/Gnomeregan/gnomeregan.cpp
index 13133405643..bfb8ede424c 100644
--- a/src/server/scripts/EasternKingdoms/Gnomeregan/gnomeregan.cpp
+++ b/src/server/scripts/EasternKingdoms/Gnomeregan/gnomeregan.cpp
@@ -196,10 +196,7 @@ public:
                 {
                     if (Creature* summon = ObjectAccessor::GetCreature(*me, *itr))
                     {
-                        if (summon->IsAlive())
-                            summon->DisappearAndDie();
-                        else
-                            summon->RemoveCorpse();
+                        summon->DespawnOrUnsummon();
                     }
                 }
         }
diff --git a/src/server/scripts/EasternKingdoms/Karazhan/karazhan.cpp b/src/server/scripts/EasternKingdoms/Karazhan/karazhan.cpp
index 6a431713222..faf4bca902c 100644
--- a/src/server/scripts/EasternKingdoms/Karazhan/karazhan.cpp
+++ b/src/server/scripts/EasternKingdoms/Karazhan/karazhan.cpp
@@ -480,8 +480,7 @@ public:
             }
             else
             {
-                me->DealDamage(me, me->GetHealth(), NULL, DIRECT_DAMAGE, SPELL_SCHOOL_MASK_NORMAL, NULL, false);
-                me->RemoveCorpse();
+                me->DespawnOrUnsummon();
             }
         }
         void EnterCombat(Unit* /*who*/) override { }
diff --git a/src/server/scripts/EasternKingdoms/SunwellPlateau/boss_felmyst.cpp b/src/server/scripts/EasternKingdoms/SunwellPlateau/boss_felmyst.cpp
index 0edada91c6b..321a4ae4299 100644
--- a/src/server/scripts/EasternKingdoms/SunwellPlateau/boss_felmyst.cpp
+++ b/src/server/scripts/EasternKingdoms/SunwellPlateau/boss_felmyst.cpp
@@ -499,9 +499,7 @@ public:
                     me->SummonCreature(NPC_DEAD, x, y, z, 0, TEMPSUMMON_TIMED_DESPAWN_OUT_OF_COMBAT, 5000);
                 }
                 (*i)->SetVisible(false);
-                (*i)->setDeathState(JUST_DIED);
-                if ((*i)->getDeathState() == CORPSE)
-                    (*i)->RemoveCorpse();
+                (*i)->DespawnOrUnsummon();
             }
         }
     };
diff --git a/src/server/scripts/EasternKingdoms/SunwellPlateau/boss_kiljaeden.cpp b/src/server/scripts/EasternKingdoms/SunwellPlateau/boss_kiljaeden.cpp
index b8e8bb91aae..9b58046036f 100644
--- a/src/server/scripts/EasternKingdoms/SunwellPlateau/boss_kiljaeden.cpp
+++ b/src/server/scripts/EasternKingdoms/SunwellPlateau/boss_kiljaeden.cpp
@@ -1174,8 +1174,7 @@ public:
                         uiTimer = 5000;
                         break;
                     case 3:
-                        me->KillSelf();
-                        me->RemoveCorpse();
+                        me->DespawnOrUnsummon();
                         break;
                 }
             } else uiTimer -=diff;
diff --git a/src/server/scripts/EasternKingdoms/Uldaman/instance_uldaman.cpp b/src/server/scripts/EasternKingdoms/Uldaman/instance_uldaman.cpp
index 0dfb5cfe69d..ee598fff9a5 100644
--- a/src/server/scripts/EasternKingdoms/Uldaman/instance_uldaman.cpp
+++ b/src/server/scripts/EasternKingdoms/Uldaman/instance_uldaman.cpp
@@ -228,8 +228,7 @@ class instance_uldaman : public InstanceMapScript
                     Creature* target = instance->GetCreature(*i);
                     if (!target || target->isDead() || target->getFaction() != 14)
                         continue;
-                    target->setDeathState(JUST_DIED);
-                    target->RemoveCorpse();
+                    target->DespawnOrUnsummon();
                 }
 
                 // Vault Walkers
@@ -238,8 +237,7 @@ class instance_uldaman : public InstanceMapScript
                     Creature* target = instance->GetCreature(*i);
                     if (!target || target->isDead() || target->getFaction() != 14)
                         continue;
-                    target->setDeathState(JUST_DIED);
-                    target->RemoveCorpse();
+                    target->DespawnOrUnsummon();
                 }
 
                 // Earthen Guardians
@@ -248,8 +246,7 @@ class instance_uldaman : public InstanceMapScript
                     Creature* target = instance->GetCreature(*i);
                     if (!target || target->isDead() || target->getFaction() != 14)
                         continue;
-                    target->setDeathState(JUST_DIED);
-                    target->RemoveCorpse();
+                    target->DespawnOrUnsummon();
                 }
             }
 
diff --git a/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/boss_anetheron.cpp b/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/boss_anetheron.cpp
index a127321c138..744a8f974ac 100644
--- a/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/boss_anetheron.cpp
+++ b/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/boss_anetheron.cpp
@@ -240,8 +240,7 @@ public:
                     Creature* boss = ObjectAccessor::GetCreature(*me, AnetheronGUID);
                     if (!boss || boss->isDead())
                     {
-                        me->setDeathState(JUST_DIED);
-                        me->RemoveCorpse();
+                        me->DespawnOrUnsummon();
                         return;
                     }
                 }
diff --git a/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/boss_azgalor.cpp b/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/boss_azgalor.cpp
index fb1f8ff102b..0427de88471 100644
--- a/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/boss_azgalor.cpp
+++ b/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/boss_azgalor.cpp
@@ -249,8 +249,7 @@ public:
                     Creature* boss = ObjectAccessor::GetCreature(*me, AzgalorGUID);
                     if (!boss || boss->isDead())
                     {
-                        me->setDeathState(JUST_DIED);
-                        me->RemoveCorpse();
+                        me->DespawnOrUnsummon();
                         return;
                     }
                 }
diff --git a/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/hyjal_trash.cpp b/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/hyjal_trash.cpp
index 2f1fad60e10..adff04f2e0c 100644
--- a/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/hyjal_trash.cpp
+++ b/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/hyjal_trash.cpp
@@ -577,8 +577,7 @@ public:
             {
                 if ((faction == 0 && LastOverronPos == 17) || (faction == 1 && LastOverronPos == 21))
                 {
-                    me->setDeathState(DEAD);
-                    me->RemoveCorpse();
+                    me->DespawnOrUnsummon();
                 }
             }
         }
@@ -677,8 +676,7 @@ public:
                 me->SetEmoteState(EMOTE_ONESHOT_ATTACK_UNARMED);
                 if ((faction == 0 && LastOverronPos == 17) || (faction == 1 && LastOverronPos == 21))
                 {
-                    me->setDeathState(DEAD);
-                    me->RemoveCorpse();
+                    me->DespawnOrUnsummon();
                 }
             }
         }
diff --git a/src/server/scripts/Kalimdor/CavernsOfTime/TheBlackMorass/the_black_morass.cpp b/src/server/scripts/Kalimdor/CavernsOfTime/TheBlackMorass/the_black_morass.cpp
index cd8ef1f253a..acb5b82c1b1 100644
--- a/src/server/scripts/Kalimdor/CavernsOfTime/TheBlackMorass/the_black_morass.cpp
+++ b/src/server/scripts/Kalimdor/CavernsOfTime/TheBlackMorass/the_black_morass.cpp
@@ -207,8 +207,7 @@ public:
                     //if we reach this it means event was running but at some point reset.
                     if (instance->GetData(TYPE_MEDIVH) == NOT_STARTED)
                     {
-                        me->DealDamage(me, me->GetHealth(), NULL, DIRECT_DAMAGE, SPELL_SCHOOL_MASK_NORMAL, NULL, false);
-                        me->RemoveCorpse();
+                        me->DespawnOrUnsummon();
                         me->Respawn();
                         return;
                     }
diff --git a/src/server/scripts/Kalimdor/TempleOfAhnQiraj/boss_skeram.cpp b/src/server/scripts/Kalimdor/TempleOfAhnQiraj/boss_skeram.cpp
index e8bedc0e8c3..b44b6013666 100644
--- a/src/server/scripts/Kalimdor/TempleOfAhnQiraj/boss_skeram.cpp
+++ b/src/server/scripts/Kalimdor/TempleOfAhnQiraj/boss_skeram.cpp
@@ -128,7 +128,7 @@ class boss_skeram : public CreatureScript
                 if (!me->IsSummon())
                     Talk(SAY_DEATH);
                 else
-                    me->RemoveCorpse();
+                    me->DespawnOrUnsummon();
             }
 
             void EnterCombat(Unit* /*who*/) override
diff --git a/src/server/scripts/Kalimdor/zone_silithus.cpp b/src/server/scripts/Kalimdor/zone_silithus.cpp
index 7b7f94a63f3..9dc9dd23070 100644
--- a/src/server/scripts/Kalimdor/zone_silithus.cpp
+++ b/src/server/scripts/Kalimdor/zone_silithus.cpp
@@ -936,7 +936,7 @@ public:
 
 void npc_qiraj_war_spawn::npc_qiraj_war_spawnAI::JustDied(Unit* /*slayer*/)
 {
-    me->RemoveCorpse();
+    me->DespawnOrUnsummon();
 
     if (!MobGUID)
         return;
diff --git a/src/server/scripts/Northrend/Naxxramas/boss_four_horsemen.cpp b/src/server/scripts/Northrend/Naxxramas/boss_four_horsemen.cpp
index bf6b3cd3558..6a9dac9f620 100644
--- a/src/server/scripts/Northrend/Naxxramas/boss_four_horsemen.cpp
+++ b/src/server/scripts/Northrend/Naxxramas/boss_four_horsemen.cpp
@@ -276,7 +276,7 @@ struct boss_four_horsemen_baseAI : public BossAI
             {
                 if (Creature* cBoss = getHorsemanHandle(boss))
                 {
-                    cBoss->DespawnOrUnsummon(0);
+                    cBoss->DespawnOrUnsummon();
                     cBoss->SetRespawnTime(15);
                 }
                 else
diff --git a/src/server/scripts/Northrend/Ulduar/Ulduar/boss_freya.cpp b/src/server/scripts/Northrend/Ulduar/Ulduar/boss_freya.cpp
index 0d3ccc74685..0d36e85cdd4 100644
--- a/src/server/scripts/Northrend/Ulduar/Ulduar/boss_freya.cpp
+++ b/src/server/scripts/Northrend/Ulduar/Ulduar/boss_freya.cpp
@@ -248,7 +248,7 @@ class npc_iron_roots : public CreatureScript
                     target->RemoveAurasDueToSpell(SPELL_ROOTS_FREYA);
                 }
 
-                me->RemoveCorpse(false);
+                me->DespawnOrUnsummon();
             }
 
         private:
diff --git a/src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_hydross_the_unstable.cpp b/src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_hydross_the_unstable.cpp
index d40f46bbaaa..5617e708b10 100644
--- a/src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_hydross_the_unstable.cpp
+++ b/src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_hydross_the_unstable.cpp
@@ -172,8 +172,7 @@ public:
             {
                 if (Creature* mob = ObjectAccessor::GetCreature(*me, beams[i]))
                 {
-                    mob->setDeathState(DEAD);
-                    mob->RemoveCorpse();
+                    mob->DespawnOrUnsummon();
                 }
             }
         }
diff --git a/src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_lady_vashj.cpp b/src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_lady_vashj.cpp
index 211be3d55f2..4a5c82d0c75 100644
--- a/src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_lady_vashj.cpp
+++ b/src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_lady_vashj.cpp
@@ -805,9 +805,9 @@ public:
                 if (!Vashj || !Vashj->IsAlive() || ENSURE_AI(boss_lady_vashj::boss_lady_vashjAI, Vashj->ToCreature()->AI())->Phase != 3)
                 {
                     // remove
-                    me->setDeathState(DEAD);
-                    me->RemoveCorpse();
                     me->setFaction(35);
+                    me->DespawnOrUnsummon();
+                    return;
                 }
 
                 CheckTimer = 1000;
diff --git a/src/server/scripts/Outland/HellfireCitadel/ShatteredHalls/boss_warchief_kargath_bladefist.cpp b/src/server/scripts/Outland/HellfireCitadel/ShatteredHalls/boss_warchief_kargath_bladefist.cpp
index c5df85fc291..51082af5744 100644
--- a/src/server/scripts/Outland/HellfireCitadel/ShatteredHalls/boss_warchief_kargath_bladefist.cpp
+++ b/src/server/scripts/Outland/HellfireCitadel/ShatteredHalls/boss_warchief_kargath_bladefist.cpp
@@ -179,11 +179,7 @@ class boss_warchief_kargath_bladefist : public CreatureScript
                 {
                     Creature* creature = ObjectAccessor::GetCreature(*me, *itr);
                     if (creature && creature->IsAlive())
-                    {
-                        creature->GetMotionMaster()->Clear(true);
-                        me->DealDamage(creature, creature->GetHealth(), NULL, DIRECT_DAMAGE, SPELL_SCHOOL_MASK_NORMAL, NULL, false);
-                        creature->RemoveCorpse();
-                    }
+                        creature->DespawnOrUnsummon();
                 }
                 adds.clear();
 
@@ -191,11 +187,7 @@ class boss_warchief_kargath_bladefist : public CreatureScript
                 {
                     Creature* creature = ObjectAccessor::GetCreature(*me, *itr);
                     if (creature && creature->IsAlive())
-                    {
-                        creature->GetMotionMaster()->Clear(true);
-                        me->DealDamage(creature, creature->GetHealth(), NULL, DIRECT_DAMAGE, SPELL_SCHOOL_MASK_NORMAL, NULL, false);
-                        creature->RemoveCorpse();
-                    }
+                        creature->DespawnOrUnsummon();
                 }
                 assassins.clear();
             }
diff --git a/src/server/scripts/Outland/TempestKeep/Mechanar/boss_nethermancer_sepethrea.cpp b/src/server/scripts/Outland/TempestKeep/Mechanar/boss_nethermancer_sepethrea.cpp
index 175caeb0dea..f66c90eead0 100644
--- a/src/server/scripts/Outland/TempestKeep/Mechanar/boss_nethermancer_sepethrea.cpp
+++ b/src/server/scripts/Outland/TempestKeep/Mechanar/boss_nethermancer_sepethrea.cpp
@@ -196,8 +196,8 @@ class npc_ragin_flames : public CreatureScript
                         if (instance->GetData(DATA_NETHERMANCER_SEPRETHREA) != IN_PROGRESS)
                         {
                             //remove
-                            me->setDeathState(JUST_DIED);
-                            me->RemoveCorpse();
+                            me->DespawnOrUnsummon();
+                            return;
                         }
                         Check_Timer = 1000;
                     } else Check_Timer -= diff;
diff --git a/src/server/scripts/Outland/TempestKeep/Mechanar/boss_pathaleon_the_calculator.cpp b/src/server/scripts/Outland/TempestKeep/Mechanar/boss_pathaleon_the_calculator.cpp
index 251954cbb73..449dc48fac4 100644
--- a/src/server/scripts/Outland/TempestKeep/Mechanar/boss_pathaleon_the_calculator.cpp
+++ b/src/server/scripts/Outland/TempestKeep/Mechanar/boss_pathaleon_the_calculator.cpp
@@ -232,8 +232,8 @@ class npc_nether_wraith : public CreatureScript
                 {
                     if (Die_Timer <= diff)
                     {
-                        me->setDeathState(JUST_DIED);
-                        me->RemoveCorpse();
+                        me->DespawnOrUnsummon();
+                        return;
                     }
                     else
                         Die_Timer -= diff;
diff --git a/src/server/scripts/Outland/zone_blades_edge_mountains.cpp b/src/server/scripts/Outland/zone_blades_edge_mountains.cpp
index 0c00d733bcb..4f9f1f18da9 100644
--- a/src/server/scripts/Outland/zone_blades_edge_mountains.cpp
+++ b/src/server/scripts/Outland/zone_blades_edge_mountains.cpp
@@ -123,11 +123,7 @@ public:
                 return;
 
             if (id == 0)
-            {
-                me->setDeathState(JUST_DIED);
-                me->RemoveCorpse();
-                me->SetHealth(0);
-            }
+                me->DespawnOrUnsummon(1);
         }
 
         void SpellHit(Unit* caster, const SpellInfo* spell) override
@@ -155,7 +151,8 @@ public:
                         EnterEvadeMode();
                         me->AddUnitFlag(UNIT_FLAG_NON_ATTACKABLE);
                         IsNihil = true;
-                    }else
+                    }
+                    else
                         AttackStart(caster);
                 }
             }
diff --git a/src/server/scripts/Outland/zone_shadowmoon_valley.cpp b/src/server/scripts/Outland/zone_shadowmoon_valley.cpp
index 025b0ece9e4..5107eb8dac1 100644
--- a/src/server/scripts/Outland/zone_shadowmoon_valley.cpp
+++ b/src/server/scripts/Outland/zone_shadowmoon_valley.cpp
@@ -384,7 +384,6 @@ public:
 
             FlyTimer = 10000;
             me->SetDisableGravity(false);
-            me->SetVisible(true);
         }
 
         void SpellHit(Unit* caster, const SpellInfo* spell) override
@@ -428,10 +427,8 @@ public:
 
                     PlayerGUID.Clear();
                 }
-                me->SetVisible(false);
-                me->SetDisableGravity(false);
-                me->DealDamage(me, me->GetHealth(), NULL, DIRECT_DAMAGE, SPELL_SCHOOL_MASK_NORMAL, NULL, false);
-                me->RemoveCorpse();
+
+                me->DespawnOrUnsummon(1);
             }
         }
 
@@ -1197,7 +1194,7 @@ public:
 
         void JustDied(Unit* /*killer*/) override
         {
-            me->RemoveCorpse();
+            me->DespawnOrUnsummon();
             if (Creature* LordIllidan = (ObjectAccessor::GetCreature(*me, LordIllidanGUID)))
                 ENSURE_AI(npc_lord_illidan_stormrage::npc_lord_illidan_stormrageAI, LordIllidan->AI())->LiveCounter();
         }
diff --git a/src/server/scripts/Spells/spell_generic.cpp b/src/server/scripts/Spells/spell_generic.cpp
index 1defc975ab5..8e5e5e633b1 100644
--- a/src/server/scripts/Spells/spell_generic.cpp
+++ b/src/server/scripts/Spells/spell_generic.cpp
@@ -4426,6 +4426,42 @@ class spell_gen_pony_mount_check : public SpellScriptLoader
         }
 };
 
+class spell_gen_shroud_of_death : public SpellScriptLoader
+{
+public:
+    spell_gen_shroud_of_death() : SpellScriptLoader("spell_gen_shroud_of_death") { }
+
+    class spell_gen_shroud_of_death_AuraScript : public AuraScript
+    {
+        PrepareAuraScript(spell_gen_shroud_of_death_AuraScript);
+
+        void OnApply(AuraEffect const* /*aurEff*/, AuraEffectHandleModes /*mode*/)
+        {
+            PreventDefaultAction();
+            GetUnitOwner()->m_serverSideVisibility.SetValue(SERVERSIDE_VISIBILITY_GHOST, GHOST_VISIBILITY_GHOST);
+            GetUnitOwner()->m_serverSideVisibilityDetect.SetValue(SERVERSIDE_VISIBILITY_GHOST, GHOST_VISIBILITY_GHOST);
+        }
+
+        void OnRemove(AuraEffect const* /*aurEff*/, AuraEffectHandleModes /*mode*/)
+        {
+            PreventDefaultAction();
+            GetUnitOwner()->m_serverSideVisibility.SetValue(SERVERSIDE_VISIBILITY_GHOST, GHOST_VISIBILITY_ALIVE);
+            GetUnitOwner()->m_serverSideVisibilityDetect.SetValue(SERVERSIDE_VISIBILITY_GHOST, GHOST_VISIBILITY_ALIVE);
+        }
+
+        void Register() override
+        {
+            OnEffectApply += AuraEffectApplyFn(spell_gen_shroud_of_death_AuraScript::OnApply, EFFECT_0, SPELL_AURA_DUMMY, AURA_EFFECT_HANDLE_REAL);
+            OnEffectRemove += AuraEffectRemoveFn(spell_gen_shroud_of_death_AuraScript::OnRemove, EFFECT_0, SPELL_AURA_DUMMY, AURA_EFFECT_HANDLE_REAL);
+        }
+    };
+
+    AuraScript* GetAuraScript() const override
+    {
+        return new spell_gen_shroud_of_death_AuraScript();
+    }
+};
+
 // 169869 - Transformation Sickness
 class spell_gen_decimatus_transformation_sickness : public SpellScriptLoader
 {
@@ -4752,6 +4788,7 @@ void AddSC_generic_spell_scripts()
     new spell_gen_landmine_knockback_achievement();
     new spell_gen_clear_debuffs();
     new spell_gen_pony_mount_check();
+    new spell_gen_shroud_of_death();
     new spell_gen_decimatus_transformation_sickness();
     new spell_gen_anetheron_summon_towering_infernal();
     new spell_gen_mark_of_kazrogal_hellfire();