Core/Spell: implement SPELL_FAILED_AURA_BOUNCED on DR spells

Closes #13695

(cherry picked from commit 5e2c5a52cd8a4ce12e189034df66b42d0d0b2c01)

1 files changed, 36 insertions, 13 deletions

diff --git a/src/server/game/Spells/Spell.cpp b/src/server/game/Spells/Spell.cpp
index 754e25011d7..a9a5c34f38a 100644
--- a/src/server/game/Spells/Spell.cpp
+++ b/src/server/game/Spells/Spell.cpp
@@ -2650,9 +2650,7 @@ SpellMissInfo Spell::DoSpellHitOnUnit(Unit* unit, uint32 effectMask)
         diminishLevel = unit->GetDiminishing(diminishGroup);
         DiminishingReturnsType type = m_spellInfo->GetDiminishingReturnsGroupType();
         // Increase Diminishing on unit, current informations for actually casts will use values above
-        if ((type == DRTYPE_PLAYER &&
-            (unit->GetCharmerOrOwnerPlayerOrPlayerItself() || (unit->GetTypeId() == TYPEID_UNIT && unit->ToCreature()->GetCreatureTemplate()->flags_extra & CREATURE_FLAG_EXTRA_ALL_DIMINISH))) ||
-            type == DRTYPE_ALL)
+        if (type == DRTYPE_ALL || (type == DRTYPE_PLAYER && unit->IsAffectedByDiminishingReturns()))
             unit->IncrDiminishing(m_spellInfo);
     }
 
@@ -3203,11 +3201,9 @@ void Spell::_cast(bool skipCheck)
     // skip check if done already (for instant cast spells for example)
     if (!skipCheck)
     {
-        uint32 param1 = 0, param2 = 0;
-        SpellCastResult castResult = CheckCast(false, &param1, &param2);
-        if (castResult != SPELL_CAST_OK)
+        auto cleanupSpell = [this, modOwner](SpellCastResult res, uint32* p1 = nullptr, uint32* p2 = nullptr)
         {
-            SendCastResult(castResult, &param1, &param2);
+            SendCastResult(res, p1, p2);
             SendInterrupted(0);
 
             if (modOwner)
@@ -3215,6 +3211,13 @@ void Spell::_cast(bool skipCheck)
 
             finish(false);
             SetExecutedCurrently(false);
+        };
+
+        uint32 param1 = 0, param2 = 0;
+        SpellCastResult castResult = CheckCast(false, &param1, &param2);
+        if (castResult != SPELL_CAST_OK)
+        {
+            cleanupSpell(castResult, &param1, &param2);
             return;
         }
 
@@ -3230,14 +3233,34 @@ void Spell::_cast(bool skipCheck)
                     {
                         // Spell will be cast after completing the trade. Silently ignore at this place
                         my_trade->SetSpell(m_spellInfo->Id, m_CastItem);
-                        SendCastResult(SPELL_FAILED_DONT_REPORT);
-                        SendInterrupted(0);
+                        cleanupSpell(SPELL_FAILED_DONT_REPORT);
+                        return;
+                    }
+                }
+            }
+        }
 
-                        modOwner->SetSpellModTakingSpell(this, false);
+        // check diminishing returns (again, only after finish cast bar, tested on retail)
+        if (Unit* target = m_targets.GetUnitTarget())
+        {
+            uint8 aura_effmask = 0;
+            for (uint8 i = 0; i < MAX_SPELL_EFFECTS; ++i)
+                if (m_spellInfo->GetEffect(i)->IsUnitOwnedAuraEffect())
+                    aura_effmask |= 1 << i;
 
-                        finish(false);
-                        SetExecutedCurrently(false);
-                        return;
+            if (aura_effmask)
+            {
+                if (DiminishingGroup diminishGroup = m_spellInfo->GetDiminishingReturnsGroupForSpell())
+                {
+                    DiminishingReturnsType type = m_spellInfo->GetDiminishingReturnsGroupType();
+                    if (type == DRTYPE_ALL || (type == DRTYPE_PLAYER && target->IsAffectedByDiminishingReturns()))
+                    {
+                        Unit* caster = m_originalCaster ? m_originalCaster : m_caster;
+                        if (target->HasStrongerAuraWithDR(m_spellInfo, caster))
+                        {
+                            cleanupSpell(SPELL_FAILED_AURA_BOUNCED);
+                            return;
+                        }
                     }
                 }
             }