Core/Units: Refactor GetCastSpellInfo to return values via return value and hide internal lookup state tracker

Port From (https://github.com/TrinityCore/TrinityCore/commit/e233079d2d8dbdc1bcd7beb593f047b26a6c4cc9)

Source/Game/Entities/Player/Player.Spells.cs

@@ -274,7 +274,7 @@ namespace Game.Entities
             return false;
         }
 
-        public override SpellInfo GetCastSpellInfo(SpellInfo spellInfo, TriggerCastFlags triggerFlag, GetCastSpellInfoContext context)
+        public override SpellInfo GetCastSpellInfo(SpellInfo spellInfo, ref TriggerCastFlags triggerFlag, GetCastSpellInfoContext context)
         {
             var overrides = m_overrideSpells.LookupByKey(spellInfo.Id);
             if (!overrides.Empty())
@@ -285,12 +285,12 @@ namespace Game.Entities
                     {
                         SpellInfo newInfo = Global.SpellMgr.GetSpellInfo(spellId, GetMap().GetDifficultyID());
                         if (newInfo != null)
-                            return GetCastSpellInfo(newInfo, triggerFlag, context);
+                            return GetCastSpellInfo(newInfo, ref triggerFlag, context);
                     }
                 }
             }
 
-            return base.GetCastSpellInfo(spellInfo, triggerFlag, context);
+            return base.GetCastSpellInfo(spellInfo, ref triggerFlag, context);
         }
 
         public void SetOverrideSpellsId(uint overrideSpellsId) { SetUpdateFieldValue(m_values.ModifyValue(m_activePlayerData).ModifyValue(m_activePlayerData.OverrideSpellsID), overrideSpellsId); }
@@ -3889,8 +3889,9 @@ namespace Game.Entities
             }
 
             // Check possible spell cast overrides
-            GetCastSpellInfoContext overrideContext = new();
+            var (overrideSpellInfo, overrideTriggerFlag) = castingUnit.GetCastSpellInfo(spellInfo);
-            spellInfo = castingUnit.GetCastSpellInfo(spellInfo, triggerFlag, overrideContext);
+            spellInfo = overrideSpellInfo;
+            triggerFlag |= overrideTriggerFlag;
             if (spellInfo.IsPassive())
             {
                 CancelPendingCastRequest();

Source/Game/Entities/Unit/Unit.Spells.cs

@@ -944,9 +944,18 @@ namespace Game.Entities
             spell.Finish(result);
         }
 
-        public virtual SpellInfo GetCastSpellInfo(SpellInfo spellInfo, TriggerCastFlags triggerFlag, GetCastSpellInfoContext context)
+        public (SpellInfo, TriggerCastFlags) GetCastSpellInfo(SpellInfo spellInfo)
         {
-            SpellInfo findMatchingAuraEffectIn(AuraType type)
+            GetCastSpellInfoContext context = new();
+            TriggerCastFlags triggerFlag = TriggerCastFlags.None;
+
+            var newSpellInfo = GetCastSpellInfo(spellInfo, ref triggerFlag, context);
+            return (newSpellInfo, triggerFlag);
+        }
+
+        public virtual SpellInfo GetCastSpellInfo(SpellInfo spellInfo, ref TriggerCastFlags triggerFlag, GetCastSpellInfoContext context)
+        {
+            SpellInfo findMatchingAuraEffectIn(AuraType type, ref TriggerCastFlags triggerFlag)
             {
                 foreach (AuraEffect auraEffect in GetAuraEffectsByType(type))
                 {
@@ -967,26 +976,25 @@ namespace Game.Entities
                                 triggerFlag &= ~TriggerCastFlags.IgnoreShapeshift;
 
                             return info;
-
                         }
                     }
                 }
 
                 return null;
-            }
+            };
 
-            SpellInfo newInfo = findMatchingAuraEffectIn(AuraType.OverrideActionbarSpells);
+            SpellInfo newInfo = findMatchingAuraEffectIn(AuraType.OverrideActionbarSpells, ref triggerFlag);
             if (newInfo != null)
             {
                 triggerFlag &= ~TriggerCastFlags.IgnoreCastTime;
-                return GetCastSpellInfo(newInfo, triggerFlag, context);
+                return GetCastSpellInfo(newInfo, ref triggerFlag, context);
             }
 
-            newInfo = findMatchingAuraEffectIn(AuraType.OverrideActionbarSpellsTriggered);
+            newInfo = findMatchingAuraEffectIn(AuraType.OverrideActionbarSpellsTriggered, ref triggerFlag);
             if (newInfo != null)
             {
                 triggerFlag |= TriggerCastFlags.IgnoreCastTime;
-                return GetCastSpellInfo(newInfo, triggerFlag, context);
+                return GetCastSpellInfo(newInfo, ref triggerFlag, context);
             }
 
             return spellInfo;
@@ -4644,7 +4652,7 @@ namespace Game.Entities
                 return true;
             }
 
-            return false;
+            return false;// no free slots left
         }
     }
 }