fix(Core/Creatures): Fixed displaying trainer npcflags that are not valid to player. (#4848)

src/server/game/Entities/Creature/Creature.cpp

@@ -1033,6 +1033,47 @@ bool Creature::isCanTrainingAndResetTalentsOf(Player* player) const
            && player->getClass() == GetCreatureTemplate()->trainer_class;
 }
 
+bool Creature::IsValidTrainerForPlayer(Player* player, uint32* npcFlags /*= nullptr*/) const
+{
+    if (!IsTrainer())
+    {
+        return false;
+    }
+
+    switch (m_creatureInfo->trainer_type)
+    {
+        case TRAINER_TYPE_CLASS:
+        case TRAINER_TYPE_PETS:
+            if (m_creatureInfo->trainer_class && m_creatureInfo->trainer_class != player->getClass())
+            {
+                if (npcFlags)
+                    *npcFlags &= ~UNIT_NPC_FLAG_TRAINER_CLASS;
+
+                return false;
+            }
+            break;
+        case TRAINER_TYPE_MOUNTS:
+            if (m_creatureInfo->trainer_race && m_creatureInfo->trainer_race != player->getRace())
+            {
+                return false;
+            }
+            break;
+        case TRAINER_TYPE_TRADESKILLS:
+            if (m_creatureInfo->trainer_spell && !player->HasSpell(m_creatureInfo->trainer_spell))
+            {
+                if (npcFlags)
+                    *npcFlags &= ~UNIT_NPC_FLAG_TRAINER_PROFESSION;
+
+                return false;
+            }
+            break;
+        default:
+            break;
+    }
+
+    return true;
+}
+
 Player* Creature::GetLootRecipient() const
 {
     if (!m_lootRecipient)

src/server/game/Entities/Creature/Creature.h

@@ -474,6 +474,7 @@ public:
     ///// TODO RENAME THIS!!!!!
     bool isCanInteractWithBattleMaster(Player* player, bool msg) const;
     bool isCanTrainingAndResetTalentsOf(Player* player) const;
+    [[nodiscard]] bool IsValidTrainerForPlayer(Player* player, uint32* npcFlags = nullptr) const;
     bool CanCreatureAttack(Unit const* victim, bool skipDistCheck = false) const;
     void LoadSpellTemplateImmunity();
     bool IsImmunedToSpell(SpellInfo const* spellInfo) override;

src/server/game/Entities/Player/Player.cpp

@@ -15074,6 +15074,11 @@ void Player::PrepareGossipMenu(WorldObject* source, uint32 menuId /*= 0*/, bool
                     canTalk = false;
                     break;
                 case GOSSIP_OPTION_TRAINER:
+                    if (!creature->IsValidTrainerForPlayer(this))
+                    {
+                        canTalk = false;
+                    }
+                    break;
                 case GOSSIP_OPTION_GOSSIP:
                 case GOSSIP_OPTION_SPIRITGUIDE:
                 case GOSSIP_OPTION_INNKEEPER:

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

@@ -19844,6 +19844,11 @@ void Unit::BuildValuesUpdate(uint8 updateType, ByteBuffer* data, Player* target)
 
                     if (!target->CanSeeSpellClickOn(creature))
                         appendValue &= ~UNIT_NPC_FLAG_SPELLCLICK;
+
+                    if (!creature->IsValidTrainerForPlayer(target, &appendValue))
+                    {
+                        appendValue &= ~UNIT_NPC_FLAG_TRAINER;
+                    }
                 }
 
                 fieldBuffer << uint32(appendValue);