feat(Core/CreatureAI): improve npc position during the combat (#3369)

+ tangent equation to find correct angle and distance when moving

+ implemented proper backward

* Improved performance + random angle margin

* chore: add tollerance calculation in instance

* improved LOS checks with movements

* implemented collisions using raycast (imported by TC)

+ improved collision detection for CanReachPositionAndGetCoords

+ improved collision check

+ set correct flags for the backward movement

+ first implementation of slope angle (to improve)

Co-authored-by: Yehonal <yehonal.azeroth@gmail.com>

src/server/game/AI/CreatureAI.cpp

@@ -257,6 +257,40 @@ bool CreatureAI::_EnterEvadeMode()
     return true;
 }
 
+void CreatureAI::MoveCircleChecks()
+{
+    Unit *victim = me->GetVictim();
+
+    if (
+        !victim ||
+        !me->IsFreeToMove() ||
+        !me->IsWithinMeleeRange(victim) ||
+        (victim->GetTypeId() != TYPEID_PLAYER && !victim->IsPet())
+    )
+    {
+        return;
+    }
+
+    me->GetMotionMaster()->MoveCircleTarget(me->GetVictim());
+}
+
+void CreatureAI::MoveBackwardsChecks() {
+    Unit *victim = me->GetVictim();
+
+    if (
+        !victim ||
+        !me->IsFreeToMove() ||
+        (victim->GetTypeId() != TYPEID_PLAYER && !victim->IsPet())
+    )
+    {
+        return;
+    }
+
+    float moveDist = CalculatePct(me->GetCombatReach() + victim->GetCombatReach(), 100);
+
+    me->GetMotionMaster()->MoveBackwards(victim, moveDist);
+}
+
 Creature* CreatureAI::DoSummon(uint32 entry, const Position& pos, uint32 despawnTime, TempSummonType summonType)
 {
     return me->SummonCreature(entry, pos, summonType, despawnTime);