Core/Spells: Fixed effects targeting the caster not hitting him immediately on spell launch if the spell targets a dest

Port From (https://github.com/TrinityCore/TrinityCore/commit/295c8f63269d966812f37a8bd8e988a9f2dc1235)

Source/Game/Movement/Generators/PathGenerator.cs

@@ -920,6 +920,15 @@ namespace Game.Movement
             return (p1 - p2).LengthSquared();
         }
 
+        public float GetPathLength()
+        {
+            float length = 0.0f;
+            for (var i = 0; i < _pathPoints.Length - 1; ++i)
+                length += (_pathPoints[i + 1] - _pathPoints[i]).Length();
+
+            return length;
+        }
+        
         public void ShortenPathUntilDist(Position pos, float dist) { ShortenPathUntilDist(new Vector3(pos.posX, pos.posY, pos.posZ), dist); }
 
         public void ShortenPathUntilDist(Vector3 target, float dist)

Source/Game/Movement/Generators/PointMovement.cs

@@ -192,7 +192,9 @@ namespace Game.Movement
 
         public void MovementInform(Unit owner)
         {
-            owner.ToCreature()?.GetAI()?.MovementInform(MovementGeneratorType.Point, _movementId);
+            // deliver EVENT_CHARGE to scripts, EVENT_CHARGE_PREPATH is just internal implementation detail of this movement generator
+            uint movementId = _movementId == EventId.ChargePrepath ? EventId.Charge : _movementId;
+            owner.ToCreature()?.GetAI()?.MovementInform(MovementGeneratorType.Point, movementId);
         }
 
         public override void UnitSpeedChanged()

Source/Game/Movement/MotionMaster.cs

@@ -702,6 +702,8 @@ namespace Game.Movement
 
             MoveCharge(dest.X, dest.Y, dest.Z, SPEED_CHARGE, EventId.ChargePrepath);
 
+            // If this is ever changed to not happen immediately then all spell effect handlers that use this must be updated
+
             // Charge movement is not started when using EVENT_CHARGE_PREPATH
             MoveSplineInit init = new(_owner);
             init.MovebyPath(path.GetPath());

Source/Game/Spells/Spell.cs

@@ -337,8 +337,36 @@ namespace Game.Spells
 
         public void RecalculateDelayMomentForDst()
         {
-            m_delayMoment = CalculateDelayMomentForDst(0.0f);
+            UpdateDelayMomentForDst(CalculateDelayMomentForDst(0.0f));
-            m_caster.m_Events.ModifyEventTime(_spellEvent, TimeSpan.FromMilliseconds(GetDelayStart() + m_delayMoment));
+        }
+
+        void UpdateDelayMomentForDst(ulong hitDelay)
+        {
+            m_delayMoment = hitDelay;
+
+            if (GetDelayStart() != 0)
+                m_caster.m_Events.ModifyEventTime(_spellEvent, TimeSpan.FromMilliseconds(GetDelayStart() + m_delayMoment));
+        }
+
+        void UpdateDelayMomentForUnitTarget(Unit unit, ulong hitDelay)
+        {
+            var itr = m_UniqueTargetInfo.Find(targetInfo => targetInfo.TargetGUID == unit.GetGUID());
+
+            ulong oldDelay = itr.TimeDelay;
+            itr.TimeDelay = hitDelay;
+
+            if (hitDelay != 0 && (m_delayMoment == 0 || m_delayMoment > hitDelay))
+                m_delayMoment = hitDelay;
+            else if (m_delayMoment != 0 && oldDelay < hitDelay)
+            {
+                // if new hit delay is greater than old delay for this target we must check all other spell targets to see if m_delayMoment can be increased
+                var minDelay = m_UniqueTargetInfo.Min(targetInfo => targetInfo.TimeDelay);
+
+                m_delayMoment = minDelay;
+            }
+
+            if (GetDelayStart() != 0)
+                m_caster.m_Events.ModifyEventTime(_spellEvent, TimeSpan.FromMilliseconds(GetDelayStart() + m_delayMoment));
         }
 
         void SelectEffectImplicitTargets(SpellEffectInfo spellEffectInfo, SpellImplicitTargetInfo targetType, ref uint processedEffectMask)
@@ -3054,7 +3082,9 @@ namespace Game.Spells
                 return 0;
             }
 
+            // when spell has a single missile we hit all targets (except caster) at the same time
             bool single_missile = m_targets.HasDst();
+            bool ignoreTargetInfoTimeDelay = single_missile;
             ulong next_time = 0;
 
             if (!m_launchHandled)
@@ -3065,21 +3095,13 @@ namespace Game.Spells
 
                 HandleLaunchPhase();
                 m_launchHandled = true;
-                if (m_delayMoment > offset)
-                {
-                    if (single_missile)
-                        return m_delayMoment;
-
-                    next_time = m_delayMoment;
-                    if ((m_UniqueTargetInfo.Count > 2 || (m_UniqueTargetInfo.Count == 1 && m_UniqueTargetInfo[0].TargetGUID == m_caster.GetGUID())) || !m_UniqueGOTargetInfo.Empty())
-                    {
-                        offset = 0; // if LaunchDelay was present then the only target that has timeDelay = 0 is m_caster - and that is the only target we want to process now
-                    }
-                }
             }
 
-            if (single_missile && offset == 0)
+            if (m_delayMoment > offset)
-                return m_delayMoment;
+            {
+                ignoreTargetInfoTimeDelay = false;
+                next_time = m_delayMoment;
+            }
 
             Player modOwner = m_caster.GetSpellModOwner();
             if (modOwner != null)
@@ -3087,7 +3109,7 @@ namespace Game.Spells
 
             PrepareTargetProcessing();
 
-            if (!m_immediateHandled && offset != 0)
+            if (!m_immediateHandled && m_delayMoment <= offset)
             {
                 _handle_immediate_phase();
                 m_immediateHandled = true;
@@ -3098,13 +3120,13 @@ namespace Game.Spells
                 List<TargetInfo> delayedTargets = new();
                 m_UniqueTargetInfo.RemoveAll(target =>
                 {
-                    if (single_missile || target.TimeDelay <= offset)
+                    if (ignoreTargetInfoTimeDelay || target.TimeDelay <= offset)
                     {
                         target.TimeDelay = offset;
                         delayedTargets.Add(target);
                         return true;
                     }
-                    else if (next_time == 0 || target.TimeDelay < next_time)
+                    else if (!single_missile && (next_time == 0 || target.TimeDelay < next_time))
                         next_time = target.TimeDelay;
                     return false;
                 });
@@ -3117,13 +3139,13 @@ namespace Game.Spells
                 List<GOTargetInfo> delayedGOTargets = new();
                 m_UniqueGOTargetInfo.RemoveAll(goTarget =>
                 {
-                    if (single_missile || goTarget.TimeDelay <= offset)
+                    if (ignoreTargetInfoTimeDelay || goTarget.TimeDelay <= offset)
                     {
                         goTarget.TimeDelay = offset;
                         delayedGOTargets.Add(goTarget);
                         return true;
                     }
-                    else if (next_time == 0 || goTarget.TimeDelay < next_time)
+                    else if (!single_missile && (next_time == 0 || goTarget.TimeDelay < next_time))
                         next_time = goTarget.TimeDelay;
                     return false;
                 });
@@ -9070,7 +9092,7 @@ namespace Game.Spells
                         if (m_Spell.m_spellInfo.LaunchDelay != 0)
                             Cypher.Assert(n_offset == (ulong)Math.Floor(m_Spell.m_spellInfo.LaunchDelay * 1000.0f));
                         else
-                            Cypher.Assert(n_offset == m_Spell.GetDelayMoment());
+                            Cypher.Assert(n_offset == m_Spell.GetDelayMoment(), $"{n_offset} == {m_Spell.GetDelayMoment()}");
 
                         // re-plan the event for the delay moment
                         m_Spell.GetCaster().m_Events.AddEvent(this, TimeSpan.FromMilliseconds(e_time + n_offset), false);

Source/Game/Spells/SpellEffects.cs

@@ -3528,21 +3528,17 @@ namespace Game.Spells
                 if (m_preGeneratedPath == null)
                 {
                     Position pos = unitTarget.GetFirstCollisionPosition(unitTarget.GetCombatReach(), unitTarget.GetRelativeAngle(m_caster.GetPosition()));
-                    if (MathFunctions.fuzzyGt(m_spellInfo.Speed, 0.0f) && m_spellInfo.HasAttribute(SpellAttr9.SpecialDelayCalculation))
+                    m_preGeneratedPath = new PathGenerator(unitCaster);
-                        speed = pos.GetExactDist(m_caster) / speed;
+                    m_preGeneratedPath.CalculatePath(pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ(), false);
-
-                    unitCaster.GetMotionMaster().MoveCharge(pos.posX, pos.posY, pos.posZ, speed, EventId.Charge, false, unitTarget, spellEffectExtraData);
                 }
-                else
-                {
-                    if (MathFunctions.fuzzyGt(m_spellInfo.Speed, 0.0f) && m_spellInfo.HasAttribute(SpellAttr9.SpecialDelayCalculation))
-                    {
-                        Vector3 pos = m_preGeneratedPath.GetActualEndPosition();
-                        speed = new Position(pos.X, pos.Y, pos.Z).GetExactDist(m_caster) / speed;
-                    }
 
-                    unitCaster.GetMotionMaster().MoveCharge(m_preGeneratedPath, speed, unitTarget, spellEffectExtraData);
+                if (MathFunctions.fuzzyGt(m_spellInfo.Speed, 0.0f) && m_spellInfo.HasAttribute(SpellAttr9.SpecialDelayCalculation))
-                }
+                    speed = m_preGeneratedPath.GetPathLength() / speed;
+
+                unitCaster.GetMotionMaster().MoveCharge(m_preGeneratedPath, speed, unitTarget, spellEffectExtraData);
+
+                // abuse implementation detail of MoveCharge accepting PathGenerator argument (instantly started spline)
+                UpdateDelayMomentForUnitTarget(unitTarget, (uint)unitCaster.MoveSpline.Duration());
             }
 
             if (effectHandleMode == SpellEffectHandleMode.HitTarget)
@@ -3578,7 +3574,18 @@ namespace Game.Spells
                     pos = unitCaster.GetFirstCollisionPosition(dist, angle);
                 }
 
-                unitCaster.GetMotionMaster().MoveCharge(pos.posX, pos.posY, pos.posZ);
+                PathGenerator path = new(unitCaster);
+                path.CalculatePath(pos.GetPositionX(), pos.GetPositionY(), pos.GetPositionZ(), false);
+
+                float speed = MathFunctions.fuzzyGt(m_spellInfo.Speed, 0.0f) ? m_spellInfo.Speed : MotionMaster.SPEED_CHARGE;
+
+                if (MathFunctions.fuzzyGt(m_spellInfo.Speed, 0.0f) && m_spellInfo.HasAttribute(SpellAttr9.SpecialDelayCalculation))
+                    speed = path.GetPathLength() / speed;
+
+                unitCaster.GetMotionMaster().MoveCharge(path, speed);
+
+                // abuse implementation detail of MoveCharge accepting PathGenerator argument (instantly started spline)
+                UpdateDelayMomentForDst((uint)unitCaster.MoveSpline.Duration());
             }
             else if (effectHandleMode == SpellEffectHandleMode.Hit)
             {