[Core] Add get messages by resId api

Lagrange.Core/Common/Interface/Api/OperationExt.cs

@@ -89,7 +89,7 @@ public static Task<bool> RecallGroupMessage(this BotContext bot, uint groupUin,
     /// <returns>Successfully recalled or not</returns>
     public static Task<bool> RecallFriendMessage(this BotContext bot, uint friendUin, MessageResult result)
         => bot.ContextCollection.Business.OperationLogic.RecallFriendMessage(friendUin, result);
-    
+
     /// <summary>
     /// Recall the group message by <see cref="MessageChain"/>
     /// </summary>
@@ -98,7 +98,7 @@ public static Task<bool> RecallFriendMessage(this BotContext bot, uint friendUin
     /// <returns>Successfully recalled or not</returns>
     public static Task<bool> RecallFriendMessage(this BotContext bot, MessageChain chain)
         => bot.ContextCollection.Business.OperationLogic.RecallFriendMessage(chain);
-    
+
     /// <summary>
     /// Fetch Notifications and requests such as friend requests and Group Join Requests
     /// </summary>
@@ -186,6 +186,11 @@ public static Task<bool> Like(this BotContext bot, uint targetUin, uint count =
         return bot.ContextCollection.Business.OperationLogic.GetC2cMessage(friendUin, startSequence, endSequence);
     }
 
+    public static Task<(int code, List<MessageChain>? chains)> GetMessagesByResId(this BotContext bot, string resId)
+    {
+        return bot.ContextCollection.Business.OperationLogic.GetMessagesByResId(resId);
+    }
+
     /// <summary>
     /// Do group clock in (群打卡)
     /// </summary>

Lagrange.Core/Internal/Context/Logic/Implementation/OperationLogic.cs

@@ -453,6 +453,17 @@ public async Task<bool> SetFriendRequest(string targetUid, bool accept)
         return results.Count != 0 ? ((GetC2cMessageEvent)results[0]).Chains : null;
     }
 
+    public async Task<(int code, List<MessageChain>? chains)> GetMessagesByResId(string resId)
+    {
+        var @event = MultiMsgDownloadEvent.Create(Collection.Keystore.Uid ?? "", resId);
+        var results = await Collection.Business.SendEvent(@event);
+
+        if (results.Count == 0) return (-9999, null);
+        var result = (MultiMsgDownloadEvent)results[0];
+
+        return (result.ResultCode, result.Chains);
+    }
+
     public async Task<List<string>?> FetchCustomFace()
     {
         var fetchCustomFaceEvent = FetchCustomFaceEvent.Create();

Lagrange.OneBot/Core/Operation/Message/GetForwardMsgOperation.cs

@@ -1,6 +1,7 @@
 using System.Text.Json;
 using System.Text.Json.Nodes;
 using Lagrange.Core;
+using Lagrange.Core.Common.Interface.Api;
 using Lagrange.Core.Internal.Event.Message;
 using Lagrange.OneBot.Core.Entity.Action;
 using Lagrange.OneBot.Core.Entity.Action.Response;
@@ -17,11 +18,14 @@ public async Task<OneBotResult> HandleOperation(BotContext context, JsonNode? pa
     {
         if (payload.Deserialize<OneBotGetForwardMsg>(SerializerOptions.DefaultOptions) is { } forwardMsg)
         {
+            var (code, chains) = await context.GetMessagesByResId(forwardMsg.Id);
+
+            if (code != 0) return new OneBotResult(null, code, "failed");
+
             var nodes = new List<OneBotSegment>();
+            if (chains == null) return new OneBotResult(new OneBotGetForwardMsgResponse(nodes), 0, "ok");
 
-            var @event = MultiMsgDownloadEvent.Create(context.ContextCollection.Keystore.Uid ?? "", forwardMsg.Id);
-            var results = await context.ContextCollection.Business.SendEvent(@event);
-            foreach (var chain in ((MultiMsgDownloadEvent)results[0]).Chains ?? throw new Exception())
+            foreach (var chain in chains)
             {
                 var parsed = service.Convert(chain);
                 var nickname = string.IsNullOrEmpty(chain.FriendInfo?.Nickname)