Core: Combat/threat system rewrite (PR #19930)

- PvE combat is now always mutual. UNIT_FLAG_IN_COMBAT is backed by actual references to the units we're in combat with.
- PvP combat is now also tracked, and almost always mutual; spells like Vanish and Feign Death can break this rule. That means we can easily determine a list of players we're fighting.
- By extension, IsInCombatWith now has sensible behavior when invoked on nonplayers.
- Threat and combat systems are no longer the same.
  - They still have an enforced relationship (threat implies combat - clearing combat clears threat)...
  - ...but we can have combat without threat. A creature (with threat list) isn't considered to be engaged until it has an entry on its threat list...
  - ...which means we can now faithfully replicate retail engage behavior. Combat on projectile launch - engagement start on projectile impact. Yay for progress!
- AI method refactor, as already ported in 6113b9d - `JustEngagedWith`, `JustEnteredCombat` and `JustExitedCombat`.
- Vehicle threat is now properly pooled on the main vehicle body (fixes #16542).
- Various edge case bug fixes for threat redirects (Misdirection "cancelling" Vigilance and similar).
- Target re-selection is now significantly faster.
- Fixed a ton of other smaller edge case bugs, probably.

Closes #7951 and #19998.

(cherry picked from commit 532ab1c7f8653d1a2e48aa1f1f8a9ba1041d4bb7)

5 files changed, 29 insertions, 56 deletions

diff --git a/src/server/scripts/EasternKingdoms/BaradinHold/boss_occuthar.cpp b/src/server/scripts/EasternKingdoms/BaradinHold/boss_occuthar.cpp
index 438230d622a..f2c8ef442ea 100644
--- a/src/server/scripts/EasternKingdoms/BaradinHold/boss_occuthar.cpp
+++ b/src/server/scripts/EasternKingdoms/BaradinHold/boss_occuthar.cpp
@@ -212,7 +212,7 @@ class FocusedFireTargetSelector : public std::unary_function<Unit *, bool>
 
         bool operator() (WorldObject* target)
         {
-            if (target == _victim && _me->GetThreatManager().getThreatList().size() > 1)
+            if (target == _victim && _me->GetThreatManager().GetThreatListSize() > 1)
                 return true;
 
             if (target->GetTypeId() != TYPEID_PLAYER)
diff --git a/src/server/scripts/EasternKingdoms/MagistersTerrace/boss_felblood_kaelthas.cpp b/src/server/scripts/EasternKingdoms/MagistersTerrace/boss_felblood_kaelthas.cpp
index 0338a3ad73f..6e0d047514e 100644
--- a/src/server/scripts/EasternKingdoms/MagistersTerrace/boss_felblood_kaelthas.cpp
+++ b/src/server/scripts/EasternKingdoms/MagistersTerrace/boss_felblood_kaelthas.cpp
@@ -198,30 +198,21 @@ public:
             if (!summonedUnit)
                 return;
 
-            ThreatContainer::StorageType const& threatlist = me->GetThreatManager().getThreatList();
-            ThreatContainer::StorageType::const_iterator i = threatlist.begin();
-            for (i = threatlist.begin(); i != threatlist.end(); ++i)
+            for (auto* ref : me->GetThreatManager().GetUnsortedThreatList())
             {
-                Unit* unit = ObjectAccessor::GetUnit(*me, (*i)->getUnitGuid());
+                Unit* unit = ref->GetVictim();
                 if (unit && unit->IsAlive())
-                {
-                    float threat = me->GetThreatManager().getThreat(unit);
-                    AddThreat(unit, threat, summonedUnit);
-                }
+                    AddThreat(unit, ref->GetThreat(), summonedUnit);
             }
         }
 
         void TeleportPlayersToSelf()
         {
-            float x = KaelLocations[0][0];
-            float y = KaelLocations[0][1];
-            me->UpdatePosition(x, y, LOCATION_Z, 0.0f);
-            ThreatContainer::StorageType threatlist = me->GetThreatManager().getThreatList();
-            ThreatContainer::StorageType::const_iterator i = threatlist.begin();
-            for (i = threatlist.begin(); i != threatlist.end(); ++i)
+            me->UpdatePosition(KaelLocations[0][0], KaelLocations[0][1], LOCATION_Z, 0.0f);
+            for (auto const& pair : me->GetCombatManager().GetPvECombatRefs())
             {
-                Unit* unit = ObjectAccessor::GetUnit(*me, (*i)->getUnitGuid());
-                if (unit && (unit->GetTypeId() == TYPEID_PLAYER))
+                Unit* unit = pair.second->GetOther(me);
+                if (unit->GetTypeId() == TYPEID_PLAYER)
                     unit->CastSpell(unit, SPELL_TELEPORT_CENTER, true);
             }
             DoCast(me, SPELL_TELEPORT_CENTER, true);
@@ -229,14 +220,11 @@ public:
 
         void CastGravityLapseKnockUp()
         {
-            ThreatContainer::StorageType threatlist = me->GetThreatManager().getThreatList();
-            ThreatContainer::StorageType::const_iterator i = threatlist.begin();
-            for (i = threatlist.begin(); i != threatlist.end(); ++i)
+            for (auto const& pair : me->GetCombatManager().GetPvECombatRefs())
             {
-                Unit* unit = ObjectAccessor::GetUnit(*me, (*i)->getUnitGuid());
-                if (unit && (unit->GetTypeId() == TYPEID_PLAYER))
+                Unit* unit = pair.second->GetOther(me);
+                if (unit->GetTypeId() == TYPEID_PLAYER)
                 {
-                    // Knockback into the air
                     CastSpellExtraArgs args;
                     args.TriggerFlags = TRIGGERED_FULL_MASK;
                     args.OriginalCaster = me->GetGUID();
@@ -247,12 +235,10 @@ public:
 
         void CastGravityLapseFly()                              // Use Fly Packet hack for now as players can't cast "fly" spells unless in map 530. Has to be done a while after they get knocked into the air...
         {
-            ThreatContainer::StorageType threatlist = me->GetThreatManager().getThreatList();
-            ThreatContainer::StorageType::const_iterator i = threatlist.begin();
-            for (i = threatlist.begin(); i != threatlist.end(); ++i)
+            for (auto const& pair : me->GetCombatManager().GetPvECombatRefs())
             {
-                Unit* unit = ObjectAccessor::GetUnit(*me, (*i)->getUnitGuid());
-                if (unit && (unit->GetTypeId() == TYPEID_PLAYER))
+                Unit* unit = pair.second->GetOther(me);
+                if (unit->GetTypeId() == TYPEID_PLAYER)
                 {
                     // Also needs an exception in spell system.
                     CastSpellExtraArgs args;
@@ -266,12 +252,10 @@ public:
 
         void RemoveGravityLapse()
         {
-            ThreatContainer::StorageType threatlist = me->GetThreatManager().getThreatList();
-            ThreatContainer::StorageType::const_iterator i = threatlist.begin();
-            for (i = threatlist.begin(); i != threatlist.end(); ++i)
+            for (auto const& pair : me->GetCombatManager().GetPvECombatRefs())
             {
-                Unit* unit = ObjectAccessor::GetUnit(*me, (*i)->getUnitGuid());
-                if (unit && (unit->GetTypeId() == TYPEID_PLAYER))
+                Unit* unit = pair.second->GetOther(me);
+                if (unit->GetTypeId() == TYPEID_PLAYER)
                 {
                     unit->RemoveAurasDueToSpell(SPELL_GRAVITY_LAPSE_FLY);
                     unit->RemoveAurasDueToSpell(SPELL_GRAVITY_LAPSE_DOT);
@@ -684,8 +668,8 @@ public:
             {
                 if (Unit* target = SelectTarget(SELECT_TARGET_RANDOM, 0, 100, true))
                 {
-                    AddThreat(target, 1.0f);
-                    me->TauntApply(target);
+                    ResetThreatList();
+                    AddThreat(target, 1000000.0f);
                     AttackStart(target);
                 }
 
diff --git a/src/server/scripts/EasternKingdoms/MagistersTerrace/boss_priestess_delrissa.cpp b/src/server/scripts/EasternKingdoms/MagistersTerrace/boss_priestess_delrissa.cpp
index e50740d8dac..21417362610 100644
--- a/src/server/scripts/EasternKingdoms/MagistersTerrace/boss_priestess_delrissa.cpp
+++ b/src/server/scripts/EasternKingdoms/MagistersTerrace/boss_priestess_delrissa.cpp
@@ -850,17 +850,12 @@ public:
             if (Blink_Timer <= diff)
             {
                 bool InMeleeRange = false;
-                ThreatContainer::StorageType const& t_list = me->GetThreatManager().getThreatList();
-                for (ThreatContainer::StorageType::const_iterator itr = t_list.begin(); itr!= t_list.end(); ++itr)
+                for (auto const& pair : me->GetCombatManager().GetPvECombatRefs())
                 {
-                    if (Unit* target = ObjectAccessor::GetUnit(*me, (*itr)->getUnitGuid()))
+                    if (pair.second->GetOther(me)->IsWithinMeleeRange(me))
                     {
-                        //if in melee range
-                        if (target->IsWithinDistInMap(me, 5))
-                        {
-                            InMeleeRange = true;
-                            break;
-                        }
+                        InMeleeRange = true;
+                        break;
                     }
                 }
 
@@ -944,17 +939,12 @@ public:
             if (Intercept_Stun_Timer <= diff)
             {
                 bool InMeleeRange = false;
-                ThreatContainer::StorageType const& t_list = me->GetThreatManager().getThreatList();
-                for (ThreatContainer::StorageType::const_iterator itr = t_list.begin(); itr!= t_list.end(); ++itr)
+                for (auto const& pair : me->GetCombatManager().GetPvECombatRefs())
                 {
-                    if (Unit* target = ObjectAccessor::GetUnit(*me, (*itr)->getUnitGuid()))
+                    if (pair.second->GetOther(me)->IsWithinMeleeRange(me))
                     {
-                        //if in melee range
-                        if (target->IsWithinDistInMap(me, ATTACK_DISTANCE))
-                        {
-                            InMeleeRange = true;
-                            break;
-                        }
+                        InMeleeRange = true;
+                        break;
                     }
                 }
 
diff --git a/src/server/scripts/EasternKingdoms/TheStockade/boss_randolph_moloch.cpp b/src/server/scripts/EasternKingdoms/TheStockade/boss_randolph_moloch.cpp
index 901a1522223..573d3c6a4d5 100644
--- a/src/server/scripts/EasternKingdoms/TheStockade/boss_randolph_moloch.cpp
+++ b/src/server/scripts/EasternKingdoms/TheStockade/boss_randolph_moloch.cpp
@@ -115,7 +115,6 @@ struct boss_randolph_moloch : public BossAI
                 me->RemoveAllAuras();
                 DoCastSelf(SPELL_VANISH);
                 me->SetReactState(REACT_PASSIVE);
-                me->SetInCombatState(true); // Prevents the boss from resetting
                 events.ScheduleEvent(EVENT_JUST_VANISHED, 2s);
                 break;
             case EVENT_JUST_VANISHED:
diff --git a/src/server/scripts/EasternKingdoms/ZulGurub/boss_mandokir.cpp b/src/server/scripts/EasternKingdoms/ZulGurub/boss_mandokir.cpp
index 5c63f224ff7..da7fff52dac 100644
--- a/src/server/scripts/EasternKingdoms/ZulGurub/boss_mandokir.cpp
+++ b/src/server/scripts/EasternKingdoms/ZulGurub/boss_mandokir.cpp
@@ -555,7 +555,7 @@ class DevastatingSlamTargetSelector : public std::unary_function<Unit *, bool>
 
         bool operator() (WorldObject* target)
         {
-            if (target == _victim && _me->GetThreatManager().getThreatList().size() > 1)
+            if (target == _victim && _me->GetThreatManager().GetThreatListSize() > 1)
                 return true;
 
             if (target->GetTypeId() != TYPEID_PLAYER)
@@ -684,7 +684,7 @@ class spell_mandokir_ohgan_orders_trigger : public SpellScriptLoader
                     caster->GetMotionMaster()->Clear();
                     caster->GetThreatManager().ClearAllThreat();
                     caster->GetThreatManager().AddThreat(target, 50000000.0f);
-                    caster->TauntApply(target);
+                    // TODO: Fixate mechanic
                 }
             }