3 files changed, 31 insertions, 2 deletions
diff --git a/src/server/game/DungeonFinding/LFGMgr.cpp b/src/server/game/DungeonFinding/LFGMgr.cpp
index 16277601b74..0d25ca0a569 100644
--- a/src/server/game/DungeonFinding/LFGMgr.cpp
+++ b/src/server/game/DungeonFinding/LFGMgr.cpp
@@ -1107,6 +1107,11 @@ void LFGMgr::UpdateProposal(uint32 proposalId, ObjectGuid guid, bool accept)
                 break;
         }
 
+        // Store the number of players that were present in group when joining RFD, used for achievement purposes
+        if (Player* player = ObjectAccessor::FindConnectedPlayer(pguid))
+            if (Group* group = player->GetGroup())
+                PlayersStore[pguid].SetNumberOfPartyMembersAtJoin(group->GetMembersCount());
+
         SetState(pguid, LFG_STATE_DUNGEON);
     }
 
@@ -1476,7 +1481,14 @@ void LFGMgr::FinishDungeon(ObjectGuid gguid, const uint32 dungeonId, Map const*
 
         // Update achievements
         if (dungeon->difficulty == DIFFICULTY_HEROIC)
-            player->UpdateCriteria(CriteriaType::CompletedLFGDungeonWithStrangers, 1);
+        {
+            uint8 lfdRandomPlayers = 0;
+            if (uint8 numParty = PlayersStore[guid].GetNumberOfPartyMembersAtJoin())
+                lfdRandomPlayers = 5 - numParty;
+            else
+                lfdRandomPlayers = 4;
+            player->UpdateCriteria(CriteriaType::CompletedLFGDungeonWithStrangers, lfdRandomPlayers);
+        }
 
         LfgReward const* reward = GetRandomDungeonReward(rDungeonId, player->getLevel());
         if (!reward)
diff --git a/src/server/game/DungeonFinding/LFGPlayerData.cpp b/src/server/game/DungeonFinding/LFGPlayerData.cpp
index 6d8612ed9fc..18488f2890a 100644
--- a/src/server/game/DungeonFinding/LFGPlayerData.cpp
+++ b/src/server/game/DungeonFinding/LFGPlayerData.cpp
@@ -21,7 +21,7 @@ namespace lfg
 {
 
 LfgPlayerData::LfgPlayerData(): m_State(LFG_STATE_NONE), m_OldState(LFG_STATE_NONE),
-    m_Team(0), m_Group(), m_Roles(0)
+    m_Team(0), m_Group(), m_Roles(0), m_NumberOfPartyMembersAtJoin(0)
 { }
 
 LfgPlayerData::~LfgPlayerData() { }
@@ -113,4 +113,14 @@ LfgDungeonSet const& LfgPlayerData::GetSelectedDungeons() const
     return m_SelectedDungeons;
 }
 
+void LfgPlayerData::SetNumberOfPartyMembersAtJoin(uint8 count)
+{
+    m_NumberOfPartyMembersAtJoin = count;
+}
+
+uint8 LfgPlayerData::GetNumberOfPartyMembersAtJoin()
+{
+    return m_NumberOfPartyMembersAtJoin;
+}
+
 } // namespace lfg
diff --git a/src/server/game/DungeonFinding/LFGPlayerData.h b/src/server/game/DungeonFinding/LFGPlayerData.h
index 5c8ad907dfe..95603b16180 100644
--- a/src/server/game/DungeonFinding/LFGPlayerData.h
+++ b/src/server/game/DungeonFinding/LFGPlayerData.h
@@ -55,6 +55,10 @@ class TC_GAME_API LfgPlayerData
         uint8 GetRoles() const;
         LfgDungeonSet const& GetSelectedDungeons() const;
 
+        // Achievement-related
+        void SetNumberOfPartyMembersAtJoin(uint8 count);
+        uint8 GetNumberOfPartyMembersAtJoin();
+
     private:
         // General
         WorldPackets::LFG::RideTicket m_Ticket;            ///< Join ticket
@@ -67,6 +71,9 @@ class TC_GAME_API LfgPlayerData
         // Queue
         uint8 m_Roles;                                     ///< Roles the player selected when joined LFG
         LfgDungeonSet m_SelectedDungeons;                  ///< Selected Dungeons when joined LFG
+
+        // Achievement-related
+        uint8 m_NumberOfPartyMembersAtJoin;
 };
 
 } // namespace lfg