Core/Spells: Fixed npcs channeling spells with SPELL_ATTR5_ALLOW_ACTIONS_DURING_CHANNEL being prevented from casting other spells during that time

src/server/game/Entities/Unit/Unit.cpp

@@ -2192,11 +2192,7 @@ void Unit::DoMeleeAttackIfReady()
         return;
 
     if (HasUnitState(UNIT_STATE_CASTING))
-    {
-        Spell* channeledSpell = GetCurrentSpell(CURRENT_CHANNELED_SPELL);
-        if (!channeledSpell || !channeledSpell->GetSpellInfo()->HasAttribute(SPELL_ATTR5_ALLOW_ACTIONS_DURING_CHANNEL))
-            return;
-    }
+        return;
 
     Unit* victim = GetVictim();
     if (!victim)
@@ -3127,7 +3123,9 @@ void Unit::SetCurrentCastSpell(Spell* pSpell)
             if (m_currentSpells[CURRENT_AUTOREPEAT_SPELL] &&
                 m_currentSpells[CURRENT_AUTOREPEAT_SPELL]->GetSpellInfo()->Id != 75)
                 InterruptSpell(CURRENT_AUTOREPEAT_SPELL);
-            AddUnitState(UNIT_STATE_CASTING);
+
+            if (!pSpell->GetSpellInfo()->HasAttribute(SPELL_ATTR5_ALLOW_ACTIONS_DURING_CHANNEL))
+                AddUnitState(UNIT_STATE_CASTING);
 
             break;
         }
@@ -3204,7 +3202,8 @@ void Unit::FinishSpell(CurrentSpellTypes spellType, SpellCastResult result /*= S
     spell->finish(result);
 }
 
-bool Unit::IsNonMeleeSpellCast(bool withDelayed, bool skipChanneled, bool skipAutorepeat, bool isAutoshoot, bool skipInstant) const
+bool Unit::IsNonMeleeSpellCast(bool withDelayed, bool skipChanneled /*= false*/, bool skipAutorepeat /*= false*/, bool isAutoshoot /*= false*/,
+    bool skipInstant /*= true*/, bool skipChanneledAllowingActions /*= false*/) const
 {
     // We don't do loop here to explicitly show that melee spell is excluded.
     // Maybe later some special spells will be excluded too.
@@ -3216,7 +3215,7 @@ bool Unit::IsNonMeleeSpellCast(bool withDelayed, bool skipChanneled, bool skipAu
     {
         if (!skipInstant || m_currentSpells[CURRENT_GENERIC_SPELL]->GetCastTime())
         {
-            if (!isAutoshoot || !(m_currentSpells[CURRENT_GENERIC_SPELL]->m_spellInfo->HasAttribute(SPELL_ATTR2_DO_NOT_RESET_COMBAT_TIMERS)))
+            if (!isAutoshoot || !m_currentSpells[CURRENT_GENERIC_SPELL]->m_spellInfo->HasAttribute(SPELL_ATTR2_DO_NOT_RESET_COMBAT_TIMERS))
                 return true;
         }
     }
@@ -3224,7 +3223,8 @@ bool Unit::IsNonMeleeSpellCast(bool withDelayed, bool skipChanneled, bool skipAu
     if (!skipChanneled && m_currentSpells[CURRENT_CHANNELED_SPELL] &&
         (m_currentSpells[CURRENT_CHANNELED_SPELL]->getState() != SPELL_STATE_FINISHED))
     {
-        if (!isAutoshoot || !(m_currentSpells[CURRENT_CHANNELED_SPELL]->m_spellInfo->HasAttribute(SPELL_ATTR2_DO_NOT_RESET_COMBAT_TIMERS)))
+        if ((!isAutoshoot || !m_currentSpells[CURRENT_CHANNELED_SPELL]->m_spellInfo->HasAttribute(SPELL_ATTR2_DO_NOT_RESET_COMBAT_TIMERS)) &&
+            (!skipChanneledAllowingActions || !m_currentSpells[CURRENT_CHANNELED_SPELL]->m_spellInfo->HasAttribute(SPELL_ATTR5_ALLOW_ACTIONS_DURING_CHANNEL)))
             return true;
     }
     // autorepeat spells may be finished or delayed, but they are still considered cast
@@ -3266,23 +3266,19 @@ int32 Unit::GetCurrentSpellCastTime(uint32 spell_id) const
 
 bool Unit::IsMovementPreventedByCasting() const
 {
-    // can always move when not casting
-    if (!HasUnitState(UNIT_STATE_CASTING))
-        return false;
-
     if (Spell* spell = m_currentSpells[CURRENT_GENERIC_SPELL])
-        if (CanCastSpellWhileMoving(spell->GetSpellInfo()) || spell->getState() == SPELL_STATE_FINISHED ||
-            !spell->m_spellInfo->InterruptFlags.HasFlag(SpellInterruptFlags::Movement))
-            return false;
+        if (!CanCastSpellWhileMoving(spell->GetSpellInfo())
+            && spell->getState() == SPELL_STATE_PREPARING && spell->m_spellInfo->InterruptFlags.HasFlag(SpellInterruptFlags::Movement))
+            return true;
 
-    // channeled spells during channel stage (after the initial cast timer) allow movement with a specific spell attribute
+    // channeled spells during channel stage (after the initial cast timer) allow movement without Moving channel interrupt flag
     if (Spell* spell = m_currentSpells[CURRENT_CHANNELED_SPELL])
-        if (spell->getState() != SPELL_STATE_FINISHED && spell->IsChannelActive())
-            if (spell->GetSpellInfo()->IsMoveAllowedChannel() || CanCastSpellWhileMoving(spell->GetSpellInfo()))
-                return false;
+        if (!CanCastSpellWhileMoving(spell->GetSpellInfo())
+            && ((spell->getState() == SPELL_STATE_PREPARING && spell->m_spellInfo->InterruptFlags.HasFlag(SpellInterruptFlags::Movement))
+                || spell->getState() == SPELL_STATE_CHANNELING && !spell->GetSpellInfo()->IsMoveAllowedChannel()))
+            return true;
 
-    // prohibit movement for all other spell casts
-    return true;
+    return false;
 }
 
 bool Unit::CanCastSpellWhileMoving(SpellInfo const* spellInfo) const

src/server/game/Entities/Unit/Unit.h

@@ -1471,7 +1471,8 @@ class TC_GAME_API Unit : public WorldObject
         // set withDelayed to true to account delayed spells as cast
         // delayed+channeled spells are always accounted as cast
         // we can skip channeled or delayed checks using flags
-        bool IsNonMeleeSpellCast(bool withDelayed, bool skipChanneled = false, bool skipAutorepeat = false, bool isAutoshoot = false, bool skipInstant = true) const;
+        bool IsNonMeleeSpellCast(bool withDelayed, bool skipChanneled = false, bool skipAutorepeat = false, bool isAutoshoot = false,
+            bool skipInstant = true, bool skipChanneledAllowingActions = false) const;
 
         // set withDelayed to true to interrupt delayed spells too
         // delayed+channeled spells are always interrupted

src/server/game/Spells/Spell.cpp

@@ -3932,7 +3932,7 @@ void Spell::_cast(bool skipCheck)
         SetDelayStart(0);
 
         if (Unit* unitCaster = m_caster->ToUnit())
-            if (unitCaster->HasUnitState(UNIT_STATE_CASTING) && !unitCaster->IsNonMeleeSpellCast(false, false, true))
+            if (unitCaster->HasUnitState(UNIT_STATE_CASTING) && !unitCaster->IsNonMeleeSpellCast(false, false, true, false, true, true))
                 unitCaster->ClearUnitState(UNIT_STATE_CASTING);
     }
     else
@@ -4376,7 +4376,7 @@ void Spell::finish(SpellCastResult result)
     if (m_spellInfo->IsChanneled())
         unitCaster->UpdateInterruptMask();
 
-    if (unitCaster->HasUnitState(UNIT_STATE_CASTING) && !unitCaster->IsNonMeleeSpellCast(false, false, true))
+    if (unitCaster->HasUnitState(UNIT_STATE_CASTING) && !unitCaster->IsNonMeleeSpellCast(false, false, true, false, true, true))
         unitCaster->ClearUnitState(UNIT_STATE_CASTING);
 
     // Unsummon summon as possessed creatures on spell cancel

src/server/scripts/EasternKingdoms/ZulAman/boss_hexlord.cpp

@@ -20,7 +20,6 @@
  * Combat timers requires to be revisited, mainly player class abilities, half of timers are guessed
  * Move spell script of spell 43421 to this file
  * Currently we generate random companions after every wipe, doubt it is correct
- * We interrupt Siphon Soul instantly to allow casting player class abilities, that's a hack
  */
 
 #include "ScriptMgr.h"
@@ -359,7 +358,6 @@ struct boss_hexlord_malacrass : public BossAI
                 break;
             case SPELL_SIPHON_SOUL:
                 Talk(SAY_CHARM);
-                me->InterruptNonMeleeSpells(false);
                 break;
             case SPELL_DRAIN_POWER:
                 Talk(SAY_DRAIN_POWER);