Core/Movement: Fix issues where creatures cancel spell casts chasing target and Implement SPELL_ATTR5_CAN_CHANNEL_WHEN_MOVING

5 files changed, 28 insertions, 8 deletions

diff --git a/src/server/game/Entities/Unit/Unit.cpp b/src/server/game/Entities/Unit/Unit.cpp
index d2d85dbfca6..9ec55343e7d 100644
--- a/src/server/game/Entities/Unit/Unit.cpp
+++ b/src/server/game/Entities/Unit/Unit.cpp
@@ -3189,6 +3189,15 @@ int32 Unit::GetCurrentSpellCastTime(uint32 spell_id) const
     return 0;
 }
 
+bool Unit::CanMoveDuringChannel() const
+{
+    if (Spell* spell = m_currentSpells[CURRENT_CHANNELED_SPELL])
+        if (spell->getState() != SPELL_STATE_FINISHED)
+            return spell->GetSpellInfo()->HasAttribute(SPELL_ATTR5_CAN_CHANNEL_WHEN_MOVING) && spell->IsChannelActive();
+
+    return false;
+}
+
 bool Unit::isInFrontInMap(Unit const* target, float distance,  float arc) const
 {
     return IsWithinDistInMap(target, distance) && HasInArc(arc, target);
diff --git a/src/server/game/Entities/Unit/Unit.h b/src/server/game/Entities/Unit/Unit.h
index 1a6fbeb44fb..47193cd0c45 100644
--- a/src/server/game/Entities/Unit/Unit.h
+++ b/src/server/game/Entities/Unit/Unit.h
@@ -1857,6 +1857,9 @@ class TC_GAME_API Unit : public WorldObject
         Spell* FindCurrentSpellBySpellId(uint32 spell_id) const;
         int32 GetCurrentSpellCastTime(uint32 spell_id) const;
 
+        // Check if our current channel spell has attribute SPELL_ATTR5_CAN_CHANNEL_WHEN_MOVING
+        bool CanMoveDuringChannel() const;
+
         SpellHistory* GetSpellHistory() { return m_spellHistory; }
         SpellHistory const* GetSpellHistory() const { return m_spellHistory; }
 
diff --git a/src/server/game/Miscellaneous/SharedDefines.h b/src/server/game/Miscellaneous/SharedDefines.h
index f9a98cffd0e..125cd69178b 100644
--- a/src/server/game/Miscellaneous/SharedDefines.h
+++ b/src/server/game/Miscellaneous/SharedDefines.h
@@ -456,7 +456,7 @@ enum SpellAttr4
 
 enum SpellAttr5
 {
-    SPELL_ATTR5_UNK0                             = 0x00000001, //  0
+    SPELL_ATTR5_CAN_CHANNEL_WHEN_MOVING          = 0x00000001, //  0 available casting channel spell when moving
     SPELL_ATTR5_NO_REAGENT_WHILE_PREP            = 0x00000002, //  1 not need reagents if UNIT_FLAG_PREPARATION
     SPELL_ATTR5_UNK2                             = 0x00000004, //  2
     SPELL_ATTR5_USABLE_WHILE_STUNNED             = 0x00000008, //  3 usable while stunned
diff --git a/src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.cpp b/src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.cpp
index 94c37a8d6a3..533b087c7a1 100644
--- a/src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.cpp
+++ b/src/server/game/Movement/MovementGenerators/TargetedMovementGenerator.cpp
@@ -36,6 +36,9 @@ void TargetedMovementGeneratorMedium<T, D>::_setTargetLocation(T* owner, bool up
     if (owner->HasUnitState(UNIT_STATE_NOT_MOVE))
         return;
 
+    if (owner->HasUnitState(UNIT_STATE_CASTING) && !owner->CanMoveDuringChannel())
+        return;
+
     if (owner->GetTypeId() == TYPEID_UNIT && !i_target->isInAccessiblePlaceFor(owner->ToCreature()))
         return;
 
@@ -139,7 +142,7 @@ bool TargetedMovementGeneratorMedium<T, D>::DoUpdate(T* owner, uint32 time_diff)
     }
 
     // prevent movement while casting spells with cast time or channel time
-    if (owner->HasUnitState(UNIT_STATE_CASTING))
+    if (owner->HasUnitState(UNIT_STATE_CASTING) && !owner->CanMoveDuringChannel())
     {
         if (!owner->IsStopped())
             owner->StopMoving();
diff --git a/src/server/game/Spells/Spell.cpp b/src/server/game/Spells/Spell.cpp
index 1ce1c433620..8329e0f3ca1 100644
--- a/src/server/game/Spells/Spell.cpp
+++ b/src/server/game/Spells/Spell.cpp
@@ -2974,12 +2974,17 @@ void Spell::prepare(SpellCastTargets const* targets, AuraEffect const* triggered
         }
 
     // don't allow channeled spells / spells with cast time to be cast while moving
+    // exception are only channeled spells that have no casttime and SPELL_ATTR5_CAN_CHANNEL_WHEN_MOVING
     // (even if they are interrupted on moving, spells with almost immediate effect get to have their effect processed before movement interrupter kicks in)
     if ((m_spellInfo->IsChanneled() || m_casttime) && m_caster->GetTypeId() == TYPEID_PLAYER && m_caster->isMoving() && m_spellInfo->InterruptFlags & SPELL_INTERRUPT_FLAG_MOVEMENT)
     {
-        SendCastResult(SPELL_FAILED_MOVING);
-        finish(false);
-        return;
+        // 1. Is a channel spell, 2. Has no casttime, 3. And has flag to allow movement during channel
+        if (!(m_spellInfo->IsChanneled() && !m_casttime && m_spellInfo->HasAttribute(SPELL_ATTR5_CAN_CHANNEL_WHEN_MOVING)))
+        {
+            SendCastResult(SPELL_FAILED_MOVING);
+            finish(false);
+            return;
+        }
     }
 
     // set timer base at cast time
@@ -3516,11 +3521,11 @@ void Spell::update(uint32 difftime)
 
     // check if the player caster has moved before the spell finished
     if ((m_caster->GetTypeId() == TYPEID_PLAYER && m_timer != 0) &&
-        m_caster->isMoving() && (m_spellInfo->InterruptFlags & SPELL_INTERRUPT_FLAG_MOVEMENT) &&
-        (m_spellInfo->Effects[0].Effect != SPELL_EFFECT_STUCK || !m_caster->HasUnitMovementFlag(MOVEMENTFLAG_FALLING_FAR)))
+        m_caster->isMoving() && (m_spellInfo->InterruptFlags & SPELL_INTERRUPT_FLAG_MOVEMENT &&
+        (m_spellInfo->Effects[0].Effect != SPELL_EFFECT_STUCK || !m_caster->HasUnitMovementFlag(MOVEMENTFLAG_FALLING_FAR))))
     {
         // don't cancel for melee, autorepeat, triggered and instant spells
-        if (!IsNextMeleeSwingSpell() && !IsAutoRepeat() && !IsTriggered())
+        if (!IsNextMeleeSwingSpell() && !IsAutoRepeat() && !IsTriggered() && !(IsChannelActive() && m_spellInfo->HasAttribute(SPELL_ATTR5_CAN_CHANNEL_WHEN_MOVING)))
             cancel();
     }