chore(PlayerScript/Hook) : Add CanSetTradeItem Hook in PlayerScript (#18583)

* chore(PlayerScript/Hook) : Add CanSetTradeItem Hook in PlayerScript

* Allowing non traded slots

* Fix typo and codestyle

src/server/game/Handlers/TradeHandler.cpp

@@ -708,6 +708,15 @@ void WorldSession::HandleSetTradeItemOpcode(WorldPacket& recvPacket)
         return;
     }
 
+    // PlayerScript Hook for checking traded items if we want to filter them in a custom module
+    if (!sScriptMgr->CanSetTradeItem(_player, item, tradeSlot))
+    {
+        // Do not send TRADE_STATUS_TRADE_CANCELED because it will cause double display of "Transaction canceled" notification
+        // On the trade initiator screen
+        SendTradeStatus(TRADE_STATUS_CLOSE_WINDOW);
+        return;
+    }
+
     my_trade->SetItem(TradeSlots(tradeSlot), item);
 }
 

src/server/game/Scripting/ScriptDefines/PlayerScript.cpp

@@ -1508,6 +1508,19 @@ bool ScriptMgr::CanInitTrade(Player* player, Player* target)
     return true;
 }
 
+bool ScriptMgr::CanSetTradeItem(Player* player, Item* tradedItem, uint8 tradeSlot)
+{
+    auto ret = IsValidBoolScript<PlayerScript>([&](PlayerScript* script)
+        {
+            return !script->CanSetTradeItem(player, tradedItem, tradeSlot);
+        });
+
+    if (ret && *ret)
+        return false;
+
+    return true;
+}
+
 void ScriptMgr::OnSetServerSideVisibility(Player* player, ServerSideVisibilityType& type, AccountTypes& sec)
 {
     ExecuteScript<PlayerScript>([&](PlayerScript* script)

src/server/game/Scripting/ScriptDefines/PlayerScript.h

@@ -421,6 +421,16 @@ public:
 
     [[nodiscard]] virtual bool CanInitTrade(Player* /*player*/, Player* /*target*/) { return true; }
 
+    /**
+     * @brief This hook called just before finishing the handling of the action of a player setting an item in a trade slot
+     *
+     * @param player Contains information about the trade initiator Player
+     * @param tradedItem Contains information about the item set in the trade slot
+     *
+     * @return True if you want to continue setting the item in the trade slot, false if you want to cancel the trade
+     */
+    [[nodiscard]] virtual bool CanSetTradeItem(Player* /*player*/, Item* /*tradedItem*/, uint8 /*tradeSlot*/) { return true; }
+
     virtual void OnSetServerSideVisibility(Player* /*player*/, ServerSideVisibilityType& /*type*/, AccountTypes& /*sec*/) { }
 
     virtual void OnSetServerSideVisibilityDetect(Player* /*player*/, ServerSideVisibilityType& /*type*/, AccountTypes& /*sec*/) { }

src/server/game/Scripting/ScriptMgr.h

@@ -440,6 +440,7 @@ public: /* PlayerScript */
     bool CanJoinLfg(Player* player, uint8 roles, lfg::LfgDungeonSet& dungeons, const std::string& comment);
     bool CanEnterMap(Player* player, MapEntry const* entry, InstanceTemplate const* instance, MapDifficulty const* mapDiff, bool loginCheck);
     bool CanInitTrade(Player* player, Player* target);
+    bool CanSetTradeItem(Player* player, Item* tradedItem, uint8 tradeSlot);
     void OnSetServerSideVisibility(Player* player, ServerSideVisibilityType& type, AccountTypes& sec);
     void OnSetServerSideVisibilityDetect(Player* player, ServerSideVisibilityType& type, AccountTypes& sec);
     void OnPlayerResurrect(Player* player, float restore_percent, bool applySickness);