fix(Core/Loot): make Loot::AddItem() honor LootItem::AllowedForPlayer() (#5774)

Original Author: @Wyrserth

src/server/game/Loot/LootMgr.cpp

@@ -474,6 +474,36 @@ void Loot::AddItem(LootStoreItem const& item)
         lootItems.push_back(generatedLoot);
         count -= proto->GetMaxStackSize();
 
+        // In some cases, a dropped item should be visible/lootable only for some players in group
+        bool canSeeItemInLootWindow = false;
+        if (auto player = ObjectAccessor::FindPlayer(lootOwnerGUID))
+        {
+            if (auto group = player->GetGroup())
+            {
+                for (auto itr = group->GetFirstMember(); itr != nullptr; itr = itr->next())
+                {
+                    if (auto member = itr->GetSource())
+                    {
+                        if (generatedLoot.AllowedForPlayer(member))
+                        {
+                            canSeeItemInLootWindow = true;
+                            break;
+                        }
+                    }
+                }
+            }
+            else if (generatedLoot.AllowedForPlayer(player))
+            {
+                canSeeItemInLootWindow = true;
+            }
+        }
+
+        if (!canSeeItemInLootWindow)
+        {
+            LOG_DEBUG("loot", "Skipping ++unlootedCount for unlootable item: %u", item.itemid);
+            continue;
+        }
+
         // non-conditional one-player only items are counted here,
         // free for all items are counted in FillFFALoot(),
         // non-ffa conditionals are counted in FillNonQuestNonFFAConditionalLoot()
@@ -489,6 +519,8 @@ bool Loot::FillLoot(uint32 lootId, LootStore const& store, Player* lootOwner, bo
     if (!lootOwner)
         return false;
 
+    lootOwnerGUID = lootOwner->GetGUID();
+
     LootTemplate const* tab = store.GetLootFor(lootId);
 
     if (!tab)

src/server/game/Loot/LootMgr.h

@@ -309,6 +309,7 @@ struct Loot
     uint32 gold;
     uint8 unlootedCount{0};
     ObjectGuid roundRobinPlayer;        // GUID of the player having the Round-Robin ownership for the loot. If 0, round robin owner has released.
+    ObjectGuid lootOwnerGUID;
     LootType loot_type{LOOT_NONE};      // required for achievement system
 
     // GUID of container that holds this loot (item_instance.entry), set for items that can be looted