Core/Creatures: moved summon duration handling to SummonInfo API and implement SummonPropertiesFlags::DespawnWhenExpired

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

@@ -809,6 +809,9 @@ void Creature::Update(uint32 diff)
         {
             Unit::Update(diff);
 
+            if (SummonInfo* summonInfo = GetSummonInfo())
+                summonInfo->UpdateRemainingDuration(Milliseconds(diff));
+
             // creature can be dead after Unit::Update call
             // CORPSE/DEAD state will processed at next tick (in other case death timer will be updated unexpectedly)
             if (!IsAlive())

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

@@ -103,6 +103,21 @@ Optional<uint8> SummonInfo::GetCreatureLevel() const
     return _creatureLevel;
 }
 
+void SummonInfo::UpdateRemainingDuration(Milliseconds deltaTime)
+{
+    if (!_remainingDuration.has_value() || _remainingDuration <= 0ms)
+        return;
+
+    *_remainingDuration -= deltaTime;
+    if (_remainingDuration <= 0ms)
+    {
+        if (DespawnsWhenExpired())
+            GetSummonedCreature()->DespawnOrUnsummon();
+        else
+            GetSummonedCreature()->KillSelf();
+    }
+}
+
 bool SummonInfo::DespawnsOnSummonerLogout() const
 {
     return _flags.HasFlag(SummonPropertiesFlags::DespawnOnSummonerLogout);

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

@@ -59,6 +59,9 @@ public:
     // Returns the level of the creature that will override the default level calculation. Nullopt when the creature uses its default values.
     Optional<uint8> GetCreatureLevel() const;
 
+    // Updates the remaining duration of a summon and triggers the expiration
+    void UpdateRemainingDuration(Milliseconds deltaTime);
+
     // Returns true when the summon will despawn when the summoner logs out. This also includes despawning and teleporting between map instances.
     bool DespawnsOnSummonerLogout() const;
     // Marks the summon to despawn when the summoner logs out. This also includes despawning and teleporting between map instaces.

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

@@ -24,6 +24,7 @@
 #include "ObjectAccessor.h"
 #include "Pet.h"
 #include "Player.h"
+#include "SummonInfo.h"
 
 TempSummon::TempSummon(SummonPropertiesEntry const* properties, Unit* owner, bool isWorldObject) :
 Creature(isWorldObject), m_Properties(properties), m_type(TEMPSUMMON_MANUAL_DESPAWN),
@@ -58,18 +59,8 @@ void TempSummon::Update(uint32 diff)
     {
         case TEMPSUMMON_MANUAL_DESPAWN:
         case TEMPSUMMON_DEAD_DESPAWN:
-            break;
         case TEMPSUMMON_TIMED_DESPAWN:
-        {
-            if (m_timer <= diff)
-            {
-                UnSummon();
-                return;
-            }
-
-            m_timer -= diff;
             break;
-        }
         case TEMPSUMMON_TIMED_DESPAWN_OUT_OF_COMBAT:
         {
             if (!IsInCombat())
@@ -216,6 +207,7 @@ void TempSummon::UpdateObjectVisibilityOnCreate()
 void TempSummon::SetTempSummonType(TempSummonType type)
 {
     m_type = type;
+    GetSummonInfo()->SetDespawnWhenExpired(true); // To maintain legacy behavior in which all summons just despawn when expired
 }
 
 void TempSummon::UnSummon(uint32 msTime)