Dynamic Creature/Go spawning:

 - True blizzlike creature spawn/respawn behavior - new creature = new object
 - Toggleable spawn groups (with C++/SAI/command options to use them)
 - Custom feature: dynamic spawn rate scaling. Accelerates respawn rate based on players in the zone.
 - Backward compatibility mode (set via group and for summons)
   to support creatures/gos that currently don't work well with this
   (this should be removed once the exceptions are fixed)

Fixes and closes #2858
Tags #8661 as fixable.
Fixes and closes #13787
Fixes #15222.

4 files changed, 47 insertions, 9 deletions

diff --git a/src/server/game/AI/ScriptedAI/ScriptedCreature.cpp b/src/server/game/AI/ScriptedAI/ScriptedCreature.cpp
index e9e252bcf35..afa7e789b7a 100644
--- a/src/server/game/AI/ScriptedAI/ScriptedCreature.cpp
+++ b/src/server/game/AI/ScriptedAI/ScriptedCreature.cpp
@@ -478,7 +478,7 @@ void BossAI::_Reset()
     events.Reset();
     summons.DespawnAll();
     scheduler.CancelAll();
-    if (instance)
+    if (instance && instance->GetBossState(_bossId) != DONE)
         instance->SetBossState(_bossId, NOT_STARTED);
 }
 
@@ -564,12 +564,12 @@ bool BossAI::CanAIAttack(Unit const* target) const
     return CheckBoundary(target);
 }
 
-void BossAI::_DespawnAtEvade(uint32 delayToRespawn /*= 30*/, Creature* who /*= nullptr*/)
+void BossAI::_DespawnAtEvade(Seconds delayToRespawn, Creature* who)
 {
-    if (delayToRespawn < 2)
+    if (delayToRespawn < Seconds(2))
     {
-        TC_LOG_ERROR("scripts", "_DespawnAtEvade called with delay of %u seconds, defaulting to 2.", delayToRespawn);
-        delayToRespawn = 2;
+        TC_LOG_ERROR("scripts", "_DespawnAtEvade called with delay of %ld seconds, defaulting to 2.", delayToRespawn.count());
+        delayToRespawn = Seconds(2);
     }
 
     if (!who)
diff --git a/src/server/game/AI/ScriptedAI/ScriptedCreature.h b/src/server/game/AI/ScriptedAI/ScriptedCreature.h
index 6fc85b6a81a..9f2e49c1ffb 100644
--- a/src/server/game/AI/ScriptedAI/ScriptedCreature.h
+++ b/src/server/game/AI/ScriptedAI/ScriptedCreature.h
@@ -366,8 +366,8 @@ class TC_GAME_API BossAI : public ScriptedAI
         void _EnterCombat();
         void _JustDied();
         void _JustReachedHome();
-        void _DespawnAtEvade(uint32 delayToRespawn = 30, Creature* who = nullptr);
-        void _DespawnAtEvade(Seconds const& time, Creature* who = nullptr) { _DespawnAtEvade(uint32(time.count()), who); }
+        void _DespawnAtEvade(Seconds delayToRespawn,  Creature* who = nullptr);
+        void _DespawnAtEvade(uint32 delayToRespawn = 30, Creature* who = nullptr) { _DespawnAtEvade(Seconds(delayToRespawn), who); }
 
         void TeleportCheaters();
 
diff --git a/src/server/game/AI/ScriptedAI/ScriptedEscortAI.cpp b/src/server/game/AI/ScriptedAI/ScriptedEscortAI.cpp
index bcf060e2ad6..5f5330c3c8d 100644
--- a/src/server/game/AI/ScriptedAI/ScriptedEscortAI.cpp
+++ b/src/server/game/AI/ScriptedAI/ScriptedEscortAI.cpp
@@ -239,13 +239,17 @@ void npc_escortAI::UpdateAI(uint32 diff)
                         return;
                     }
 
-                    if (m_bCanInstantRespawn)
+                    if (m_bCanInstantRespawn && !sWorld->getBoolConfig(CONFIG_RESPAWN_DYNAMIC_ESCORTNPC))
                     {
                         me->setDeathState(JUST_DIED);
                         me->Respawn();
                     }
                     else
+                    {
+                        if (sWorld->getBoolConfig(CONFIG_RESPAWN_DYNAMIC_ESCORTNPC))
+                            me->GetMap()->RemoveRespawnTime(SPAWN_TYPE_CREATURE, me->GetSpawnId(), true);
                         me->DespawnOrUnsummon();
+                    }
 
                     return;
                 }
@@ -280,11 +284,17 @@ void npc_escortAI::UpdateAI(uint32 diff)
             {
                 TC_LOG_DEBUG("scripts", "EscortAI failed because player/group was to far away or not found");
 
-                if (m_bCanInstantRespawn)
+                bool isEscort = false;
+                if (CreatureData const* cdata = me->GetCreatureData())
+                    isEscort = (sWorld->getBoolConfig(CONFIG_RESPAWN_DYNAMIC_ESCORTNPC) && (cdata->spawnGroupData->flags & SPAWNGROUP_FLAG_ESCORTQUESTNPC));
+
+                if (m_bCanInstantRespawn && !isEscort)
                 {
                     me->setDeathState(JUST_DIED);
                     me->Respawn();
                 }
+                else if (m_bCanInstantRespawn && isEscort)
+                    me->GetMap()->RemoveRespawnTime(SPAWN_TYPE_CREATURE, me->GetSpawnId(), true);
                 else
                     me->DespawnOrUnsummon();
 
@@ -424,6 +434,22 @@ void npc_escortAI::SetRun(bool on)
 /// @todo get rid of this many variables passed in function.
 void npc_escortAI::Start(bool isActiveAttacker /* = true*/, bool run /* = false */, ObjectGuid playerGUID /* = 0 */, Quest const* quest /* = nullptr */, bool instantRespawn /* = false */, bool canLoopPath /* = false */, bool resetWaypoints /* = true */)
 {
+    // Queue respawn from the point it starts
+    if (Map* map = me->GetMap())
+    {
+        if (CreatureData const* cdata = me->GetCreatureData())
+        {
+            if (SpawnGroupTemplateData const* groupdata = cdata->spawnGroupData)
+            {
+                if (sWorld->getBoolConfig(CONFIG_RESPAWN_DYNAMIC_ESCORTNPC) && (groupdata->flags & SPAWNGROUP_FLAG_ESCORTQUESTNPC) && !map->GetCreatureRespawnTime(me->GetSpawnId()))
+                {
+                    me->SetRespawnTime(me->GetRespawnDelay());
+                    me->SaveRespawnTime();
+                }
+            }
+        }
+    }
+
     if (me->GetVictim())
     {
         TC_LOG_ERROR("scripts.escortai", "TSCR ERROR: EscortAI (script: %s, creature entry: %u) attempts to Start while in combat", me->GetScriptName().c_str(), me->GetEntry());
@@ -567,3 +593,14 @@ bool npc_escortAI::GetWaypointPosition(uint32 pointId, float& x, float& y, float
 
     return false;
 }
+
+bool npc_escortAI::IsEscortNPC(bool onlyIfActive) const
+{
+    if (!onlyIfActive)
+        return true;
+
+    if (GetEventStarterGUID())
+        return true;
+
+    return false;
+}
diff --git a/src/server/game/AI/ScriptedAI/ScriptedEscortAI.h b/src/server/game/AI/ScriptedAI/ScriptedEscortAI.h
index 754d96dced9..7d6f210f034 100644
--- a/src/server/game/AI/ScriptedAI/ScriptedEscortAI.h
+++ b/src/server/game/AI/ScriptedAI/ScriptedEscortAI.h
@@ -107,6 +107,7 @@ struct TC_GAME_API npc_escortAI : public ScriptedAI
         bool GetAttack() const { return m_bIsActiveAttacker; }//used in EnterEvadeMode override
         void SetCanAttack(bool attack) { m_bIsActiveAttacker = attack; }
         ObjectGuid GetEventStarterGUID() const { return m_uiPlayerGUID; }
+        virtual bool IsEscortNPC(bool isEscorting) const override;
 
     protected:
         Player* GetPlayerForEscort();