feat: Add dungeon key count Subscription field

backend/app/Savor22b/GraphTypes/Types/DungeonStateType.cs

@@ -0,0 +1,24 @@
+namespace Savor22b.GraphTypes.Types;
+
+using GraphQL.Types;
+using Libplanet.Blockchain;
+using Libplanet.Net;
+using Libplanet.Store;
+using Savor22b.States;
+
+public class DungeonStateType : ObjectGraphType<DungeonState>
+{
+    public DungeonStateType(
+        BlockChain blockChain,
+        BlockRenderer blockRenderer,
+        IStore store,
+        Swarm? swarm = null
+    )
+    {
+        Field<NonNullGraphType<IntGraphType>>(
+            name: "DungeonKeyCount",
+            description: "The number of dungeon keys the user has.",
+            resolve: context => context.Source.GetDungeonKeyCount(blockChain.Count)
+        );
+    }
+}

backend/app/Savor22b/GraphTypes/Types/UserStateType.cs

@@ -17,5 +17,10 @@ public UserStateType()
             description: "The village state of the user.",
             resolve: context => context.Source.VillageState
         );
+        Field<NonNullGraphType<DungeonStateType>>(
+            name: "dungeonState",
+            description: "The dungeon state of the user.",
+            resolve: context => context.Source.DungeonState
+        );
     }
 }

backend/app/Savor22b/States/DungeonState.cs

@@ -44,6 +44,11 @@ public IValue Serialize()
         });
     }
 
+    public int GetDungeonKeyCount(long blockIndex)
+    {
+        return MaxDungeonKey - GetCurrentDungeonKeyHistories(blockIndex).Count;
+    }
+
     public ImmutableList<DungeonKeyHistory> GetCurrentDungeonKeyHistories(long blockIndex)
     {
         var lowerBoundIndex = blockIndex - (MaxDungeonKey * DungeonKeyChargeIntervalBlock);