Core/AI: initial support for monster sparring (#17673)

(cherry picked from commit 303066509d907d4836a935371492092f05d47c7e)

5 files changed, 67 insertions, 10 deletions

diff --git a/src/server/game/AI/CoreAI/UnitAI.cpp b/src/server/game/AI/CoreAI/UnitAI.cpp
index 28f1308b57f..52a6aaff65e 100644
--- a/src/server/game/AI/CoreAI/UnitAI.cpp
+++ b/src/server/game/AI/CoreAI/UnitAI.cpp
@@ -56,16 +56,25 @@ void UnitAI::DoMeleeAttackIfReady()
     if (!me->IsWithinMeleeRange(victim))
         return;
 
+    bool sparAttack = me->GetFactionTemplateEntry()->ShouldSparAttack() && victim->GetFactionTemplateEntry()->ShouldSparAttack();
     //Make sure our attack is ready and we aren't currently casting before checking distance
     if (me->isAttackReady())
     {
-        me->AttackerStateUpdate(victim);
+        if (sparAttack)
+            me->FakeAttackerStateUpdate(victim);
+        else
+            me->AttackerStateUpdate(victim);
+
         me->resetAttackTimer();
     }
 
     if (me->haveOffhandWeapon() && me->isAttackReady(OFF_ATTACK))
     {
-        me->AttackerStateUpdate(victim, OFF_ATTACK);
+        if (sparAttack)
+            me->FakeAttackerStateUpdate(victim, OFF_ATTACK);
+        else
+            me->AttackerStateUpdate(victim, OFF_ATTACK);
+
         me->resetAttackTimer(OFF_ATTACK);
     }
 }
diff --git a/src/server/game/DataStores/DB2Structure.h b/src/server/game/DataStores/DB2Structure.h
index f889b4e5410..8a06351d288 100644
--- a/src/server/game/DataStores/DB2Structure.h
+++ b/src/server/game/DataStores/DB2Structure.h
@@ -913,6 +913,7 @@ struct FactionTemplateEntry
         return EnemyMask == 0 && FriendMask == 0;
     }
     bool IsContestedGuardFaction() const { return (Flags & FACTION_TEMPLATE_FLAG_CONTESTED_GUARD) != 0; }
+    bool ShouldSparAttack() const { return (Flags & FACTION_TEMPLATE_ENEMY_SPAR) != 0; }
 };
 
 struct GameObjectsEntry
diff --git a/src/server/game/DataStores/DBCEnums.h b/src/server/game/DataStores/DBCEnums.h
index fe529ed3076..5903be4f347 100644
--- a/src/server/game/DataStores/DBCEnums.h
+++ b/src/server/game/DataStores/DBCEnums.h
@@ -535,6 +535,7 @@ enum SpawnMask
 
 enum FactionTemplateFlags
 {
+    FACTION_TEMPLATE_ENEMY_SPAR             = 0x00000020,   // guessed, sparring with enemies?
     FACTION_TEMPLATE_FLAG_PVP               = 0x00000800,   // flagged for PvP
     FACTION_TEMPLATE_FLAG_CONTESTED_GUARD   = 0x00001000,   // faction will attack players that were involved in PvP combats
     FACTION_TEMPLATE_FLAG_HOSTILE_BY_DEFAULT= 0x00002000
diff --git a/src/server/game/Entities/Unit/Unit.cpp b/src/server/game/Entities/Unit/Unit.cpp
index 75222e078b0..750643ec126 100644
--- a/src/server/game/Entities/Unit/Unit.cpp
+++ b/src/server/game/Entities/Unit/Unit.cpp
@@ -1895,6 +1895,50 @@ void Unit::AttackerStateUpdate (Unit* victim, WeaponAttackType attType, bool ext
     }
 }
 
+void Unit::FakeAttackerStateUpdate(Unit* victim, WeaponAttackType attType /*= BASE_ATTACK*/)
+{
+    if (HasUnitState(UNIT_STATE_CANNOT_AUTOATTACK) || HasFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_PACIFIED))
+        return;
+
+    if (!victim->IsAlive())
+        return;
+
+    if ((attType == BASE_ATTACK || attType == OFF_ATTACK) && !IsWithinLOSInMap(victim))
+        return;
+
+    CombatStart(victim);
+    RemoveAurasWithInterruptFlags(AURA_INTERRUPT_FLAG_MELEE_ATTACK);
+
+    if (attType != BASE_ATTACK && attType != OFF_ATTACK)
+        return;                                             // ignore ranged case
+
+    if (GetTypeId() == TYPEID_UNIT && !HasFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_PLAYER_CONTROLLED))
+        SetFacingToObject(victim); // update client side facing to face the target (prevents visual glitches when casting untargeted spells)
+
+    CalcDamageInfo damageInfo;
+    damageInfo.attacker = this;
+    damageInfo.target = victim;
+    damageInfo.damageSchoolMask = GetMeleeDamageSchoolMask();
+    damageInfo.attackType = attType;
+    damageInfo.damage = 0;
+    damageInfo.cleanDamage = 0;
+    damageInfo.absorb = 0;
+    damageInfo.resist = 0;
+    damageInfo.blocked_amount = 0;
+
+    damageInfo.TargetState = VICTIMSTATE_HIT;
+    damageInfo.HitInfo = HITINFO_AFFECTS_VICTIM | HITINFO_NORMALSWING | HITINFO_FAKE_DAMAGE;
+    if (attType == OFF_ATTACK)
+        damageInfo.HitInfo |= HITINFO_OFFHAND;
+
+    damageInfo.procAttacker = PROC_FLAG_NONE;
+    damageInfo.procVictim = PROC_FLAG_NONE;
+    damageInfo.procEx = PROC_EX_NONE;
+    damageInfo.hitOutCome = MELEE_HIT_NORMAL;
+
+    SendAttackStateUpdate(&damageInfo);
+}
+
 void Unit::HandleProcExtraAttackFor(Unit* victim)
 {
     while (m_extraAttacks)
diff --git a/src/server/game/Entities/Unit/Unit.h b/src/server/game/Entities/Unit/Unit.h
index 1cc7536ea8c..58cab981dfc 100644
--- a/src/server/game/Entities/Unit/Unit.h
+++ b/src/server/game/Entities/Unit/Unit.h
@@ -362,20 +362,21 @@ enum HitInfo
     HITINFO_FULL_RESIST         = 0x00000080,
     HITINFO_PARTIAL_RESIST      = 0x00000100,
     HITINFO_CRITICALHIT         = 0x00000200,               // critical hit
-    // 0x00000400
-    // 0x00000800
+    HITINFO_UNK10               = 0x00000400,
+    HITINFO_UNK11               = 0x00000800,
     HITINFO_UNK12               = 0x00001000,
     HITINFO_BLOCK               = 0x00002000,               // blocked damage
-    // 0x00004000                                           // Hides worldtext for 0 damage
-    // 0x00008000                                           // Related to blood visual
+    HITINFO_UNK14               = 0x00004000,               // set only if meleespellid is present//  no world text when victim is hit for 0 dmg(HideWorldTextForNoDamage?)
+    HITINFO_UNK15               = 0x00008000,               // player victim?// something related to blod sprut visual (BloodSpurtInBack?)
     HITINFO_GLANCING            = 0x00010000,
     HITINFO_CRUSHING            = 0x00020000,
     HITINFO_NO_ANIMATION        = 0x00040000,
-    // 0x00080000
-    // 0x00100000
+    HITINFO_UNK19               = 0x00080000,
+    HITINFO_UNK20               = 0x00100000,
     HITINFO_SWINGNOHITSOUND     = 0x00200000,               // unused?
-    // 0x00400000
-    HITINFO_RAGE_GAIN           = 0x00800000
+    HITINFO_UNK22               = 0x00400000,
+    HITINFO_RAGE_GAIN           = 0x00800000,
+    HITINFO_FAKE_DAMAGE         = 0x01000000                // enables damage animation even if no damage done, set only if no damage
 };
 
 //i would like to remove this: (it is defined in item.h
@@ -1549,6 +1550,7 @@ class TC_GAME_API Unit : public WorldObject
 
         void HandleEmoteCommand(uint32 anim_id);
         void AttackerStateUpdate (Unit* victim, WeaponAttackType attType = BASE_ATTACK, bool extra = false);
+        void FakeAttackerStateUpdate(Unit* victim, WeaponAttackType attType = BASE_ATTACK);
 
         void CalculateMeleeDamage(Unit* victim, uint32 damage, CalcDamageInfo* damageInfo, WeaponAttackType attackType = BASE_ATTACK);
         void DealMeleeDamage(CalcDamageInfo* damageInfo, bool durabilityLoss);