Core/Spells: enable and implement SMSG_MISSILE_CANCEL

Port From (https://github.com/TrinityCore/TrinityCore/commit/71db17220ae67dc6a354e88451ffc0700fe6c5f9)

Source/Framework/Dynamic/EventSystem.cs

@@ -115,6 +115,8 @@ namespace Framework.Dynamic
             return (m_time + t_offset);
         }
 
+        public SortedMultiMap<ulong, BasicEvent> GetEvents() { return m_events; }
+
         ulong m_time;
         SortedMultiMap<ulong, BasicEvent> m_events = new SortedMultiMap<ulong, BasicEvent>();
     }

Source/Game/Entities/Unit/Unit.cs

@@ -1067,6 +1067,32 @@ namespace Game.Entities
             SendMessageToSet(playSpellVisualKit, true);
         }
 
+        void CancelSpellMissiles(uint spellId, bool reverseMissile = false)
+        {
+            bool hasMissile = false;
+            foreach (var pair in m_Events.GetEvents())
+            {
+                Spell spell = Spell.ExtractSpellFromEvent(pair.Value);
+                if (spell != null)
+                {
+                    if (spell.GetSpellInfo().Id == spellId)
+                    {
+                        pair.Value.ScheduleAbort();
+                        hasMissile = true;
+                    }
+                }
+            }
+
+            if (hasMissile)
+            {
+                MissileCancel packet = new MissileCancel();
+                packet.OwnerGUID = GetGUID();
+                packet.SpellID = spellId;
+                packet.Reverse = reverseMissile;
+                SendMessageToSet(packet, false);
+            }
+        }
+
         public void UnsummonAllTotems()
         {
             for (byte i = 0; i < SharedConst.MaxSummonSlot; ++i)

Source/Game/Networking/Packets/SpellPackets.cs

@@ -1119,6 +1119,23 @@ namespace Game.Networking.Packets
         public uint Result;
     }
 
+    class MissileCancel : ServerPacket
+    {
+        public MissileCancel() : base(ServerOpcodes.MissileCancel) { }
+
+        public override void Write()
+        {
+            _worldPacket.WritePackedGuid(OwnerGUID);
+            _worldPacket.WriteUInt32(SpellID);
+            _worldPacket.WriteBit(Reverse);
+            _worldPacket.FlushBits();
+        }
+
+        public ObjectGuid OwnerGUID;
+        public bool Reverse;
+        public uint SpellID;
+    }
+    
     //Structs
     public struct SpellLogPowerData
     {

Source/Game/Spells/Spell.cs

@@ -4418,6 +4418,15 @@ namespace Game.Spells
                 Global.SpellMgr.GetSpellEffectHandler(eff).Invoke(this, i);
         }
 
+        public static Spell ExtractSpellFromEvent(BasicEvent basicEvent)
+        {
+            SpellEvent spellEvent = (SpellEvent)basicEvent;
+            if (spellEvent != null)
+                return spellEvent.GetSpell();
+
+            return null;
+        }
+        
         public SpellCastResult CheckCast(bool strict)
         {
             uint param1 = 0, param2 = 0;
@@ -7998,17 +8007,21 @@ namespace Game.Spells
             m_Spell.GetCaster().m_Events.AddEvent(this, e_time + 1, false);
             return false;                                           // event not complete
         }
+
         public override void Abort(ulong e_time)
         {
             // oops, the spell we try to do is aborted
             if (m_Spell.GetState() != SpellState.Finished)
                 m_Spell.Cancel();
         }
+
         public override bool IsDeletable()
         {
             return m_Spell.IsDeletable();
         }
 
+        public Spell GetSpell() { return m_Spell; }
+
         Spell m_Spell;
     }