Core/Spells: Start spells triggered by SPELL_EFFECT_FORCE_CAST_2 without any trigger flags

(cherry picked from commit 0fd418eb7472039bb953a7167a48f6495c2b2efb)

# Conflicts:
#	src/server/game/Spells/SpellEffects.cpp

3 files changed, 45 insertions, 3 deletions

diff --git a/src/server/game/Spells/Spell.cpp b/src/server/game/Spells/Spell.cpp
index c52543ec6d9..b697a8e2a04 100644
--- a/src/server/game/Spells/Spell.cpp
+++ b/src/server/game/Spells/Spell.cpp
@@ -3861,6 +3861,8 @@ void Spell::_cast(bool skipCheck)
     if (!m_spellInfo->HasAttribute(SPELL_ATTR12_START_COOLDOWN_ON_CAST_START))
         SendSpellCooldown();
 
+    m_spellState = SPELL_STATE_LAUNCHED;
+
     if (!m_spellInfo->LaunchDelay)
     {
         HandleLaunchPhase();
@@ -3886,7 +3888,6 @@ void Spell::_cast(bool skipCheck)
 
         // Okay, maps created, now prepare flags
         m_immediateHandled = false;
-        m_spellState = SPELL_STATE_LAUNCHED;
         SetDelayStart(0);
 
         if (Unit* unitCaster = m_caster->ToUnit())
diff --git a/src/server/game/Spells/Spell.h b/src/server/game/Spells/Spell.h
index 48bd69d3cf7..9a742e2d42b 100644
--- a/src/server/game/Spells/Spell.h
+++ b/src/server/game/Spells/Spell.h
@@ -310,6 +310,7 @@ class TC_GAME_API Spell
         void EffectLearnPetSpell();
         void EffectWeaponDmg();
         void EffectForceCast();
+        void EffectForceCast2();
         void EffectTriggerSpell();
         void EffectTriggerMissileSpell();
         void EffectThreat();
diff --git a/src/server/game/Spells/SpellEffects.cpp b/src/server/game/Spells/SpellEffects.cpp
index 0b5edea46a0..2512b64a8cc 100644
--- a/src/server/game/Spells/SpellEffects.cpp
+++ b/src/server/game/Spells/SpellEffects.cpp
@@ -244,7 +244,7 @@ NonDefaultConstructible<SpellEffectHandlerFn> SpellEffectHandlers[TOTAL_SPELL_EF
     &Spell::EffectCreateItem2,                              //157 SPELL_EFFECT_CREATE_ITEM_2            create item or create item template and replace by some randon spell loot item
     &Spell::EffectMilling,                                  //158 SPELL_EFFECT_MILLING                  milling
     &Spell::EffectRenamePet,                                //159 SPELL_EFFECT_ALLOW_RENAME_PET         allow rename pet once again
-    &Spell::EffectForceCast,                                //160 SPELL_EFFECT_FORCE_CAST_2
+    &Spell::EffectForceCast2,                               //160 SPELL_EFFECT_FORCE_CAST_2
     &Spell::EffectTalentSpecCount,                          //161 SPELL_EFFECT_TALENT_SPEC_COUNT        second talent spec (learn/revert)
     &Spell::EffectActivateSpec,                             //162 SPELL_EFFECT_TALENT_SPEC_SELECT       activate primary/secondary spec
     &Spell::EffectNULL,                                     //163 SPELL_EFFECT_OBLITERATE_ITEM
@@ -808,7 +808,7 @@ void Spell::EffectForceCast()
             return;
     }
 
-    CastSpellExtraArgs args(TRIGGERED_FULL_MASK & ~(TRIGGERED_IGNORE_POWER_COST | TRIGGERED_IGNORE_REAGENT_COST));
+    CastSpellExtraArgs args(TRIGGERED_FULL_MASK & ~(TRIGGERED_IGNORE_POWER_COST | TRIGGERED_CAST_DIRECTLY | TRIGGERED_IGNORE_REAGENT_COST));
     if (effectInfo->Effect == SPELL_EFFECT_FORCE_CAST_WITH_VALUE)
         for (std::size_t i = 0; i < spellInfo->GetEffects().size(); ++i)
             args.AddSpellMod(SpellValueMod(SPELLVALUE_BASE_POINT0 + i), damage);
@@ -816,6 +816,46 @@ void Spell::EffectForceCast()
     unitTarget->CastSpell(m_caster, spellInfo->Id, args);
 }
 
+void Spell::EffectForceCast2()
+{
+    if (effectHandleMode != SPELL_EFFECT_HANDLE_LAUNCH_TARGET)
+        return;
+
+    if (!unitTarget)
+        return;
+
+    uint32 triggered_spell_id = effectInfo->TriggerSpell;
+    if (triggered_spell_id == 0)
+    {
+        TC_LOG_WARN("spells.effect.nospell", "Spell::EffectForceCast2: Spell {} [EffectIndex: {}] does not have triggered spell.", m_spellInfo->Id, effectInfo->EffectIndex);
+        return;
+    }
+
+    // normal case
+    if (!sSpellMgr->GetSpellInfo(triggered_spell_id, GetCastDifficulty()))
+    {
+        TC_LOG_ERROR("spells.effect.nospell", "Spell::EffectForceCast2 of spell {}: triggering unknown spell id {}.", m_spellInfo->Id, triggered_spell_id);
+        return;
+    }
+
+    // Start the cast during next update tick
+    // This is neccessary to preserve proper SMSG_SPELL_START and SMSG_SPELL_GO packet sequence
+    // (if packet sequence is not preserved then client cast bar in UI bugs and doesn't stop when the spell is interrupted)
+    // Triggered spells from effects handled during launch phase (such as SPELL_EFFECT_TRIGGER_SPELL)
+    // normally have their SMSG_SPELL_GO sent before parent spell SMSG_SPELL_GO
+    // SPELL_EFFECT_FORCE_CAST_2 requires these packets to be sent after parent spell
+    // but also needs to be handled during launch phase as well
+    unitTarget->m_Events.AddEventAtOffset([triggered_spell_id, target = CastSpellTargetArg(m_caster), caster = unitTarget]() mutable
+    {
+        if (!target.Targets)
+            return;
+
+        target.Targets->Update(caster);
+
+        caster->CastSpell(target, triggered_spell_id);
+    }, 0ms);
+}
+
 void Spell::EffectTriggerRitualOfSummoning()
 {
     if (effectHandleMode != SPELL_EFFECT_HANDLE_HIT)