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)

6 files changed, 7 insertions, 12 deletions

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;