From 58a459bb15a736f245f6f2ccf1e9fcc8a6375568 Mon Sep 17 00:00:00 2001
From: Rogee <rogee@ipao.vip>
Date: Tue, 22 Sep 2026 17:32:16 +0800
Subject: [PATCH] Split large connection-authorized batches by payload size

---
 .../RemoteAgentHostedService.cs               | 61 ++++++++++++++-----
 1 file changed, 47 insertions(+), 14 deletions(-)

diff --git a/node-agent/WxAgent.Service/RemoteAgentHostedService.cs b/node-agent/WxAgent.Service/RemoteAgentHostedService.cs
index 21e4613..922fb94 100644
--- a/node-agent/WxAgent.Service/RemoteAgentHostedService.cs
+++ b/node-agent/WxAgent.Service/RemoteAgentHostedService.cs
@@ -192,25 +192,41 @@ public sealed class RemoteAgentHostedService(
                 continue;
 
             var sequence = sourceChanged ? 1 : checkpoint.ConfirmedSequence + 1;
-            var remainingConversations = collection.Conversations.ToList();
-            var remainingMessages = collection.Messages.ToList();
+            var conversationIndex = 0;
+            var messageIndex = 0;
             var cursorStartJson = SerializeCursors(cursorStart);
             var cursorEndJson = SerializeCursors(collection.NextCursors);
             var allQueued = true;
             RemoteSyncBatch? lastQueuedBatch = null;
-            while (remainingConversations.Count > 0 || remainingMessages.Count > 0 || lastQueuedBatch is null)
+            while (conversationIndex < collection.Conversations.Count || messageIndex < collection.Messages.Count || lastQueuedBatch is null)
             {
-                var conversationCount = Math.Min(remainingConversations.Count, RemoteDataProtocol.MaxBatchMessages);
-                var conversations = remainingConversations.Take(conversationCount).ToArray();
-                remainingConversations.RemoveRange(0, conversationCount);
-                var messageCount = Math.Min(remainingMessages.Count, RemoteDataProtocol.MaxBatchMessages - conversations.Length);
-                var messages = remainingMessages.Take(messageCount).ToArray();
-                remainingMessages.RemoveRange(0, messageCount);
-                var batch = new RemoteSyncBatch(
-                    remote.NodeId!, account.AccountId, Guid.NewGuid().ToString("N"), collection.SourceGeneration,
-                    "messages", sequence++, cursorStartJson, cursorEndJson, string.Empty,
-                    collection.IsComplete ? "complete" : "partial", conversations, messages);
-                batch = batch with { PayloadHash = RemoteDataBatchAuthorization.ComputePayloadHash(batch) };
+                var conversations = new List<RemoteSyncConversation>();
+                var messages = new List<RemoteSyncMessage>();
+                while (conversationIndex < collection.Conversations.Count && conversations.Count + messages.Count < RemoteDataProtocol.MaxBatchMessages)
+                {
+                    conversations.Add(collection.Conversations[conversationIndex]);
+                    var candidate = CreateSyncBatch(remote, account.AccountId, collection.SourceGeneration, sequence, cursorStartJson, cursorEndJson, collection.IsComplete, conversations, messages);
+                    if (JsonSerializer.SerializeToUtf8Bytes(candidate, RemoteJson.Options).LongLength > RemoteDataProtocol.MaxBatchBytes)
+                    {
+                        conversations.RemoveAt(conversations.Count - 1);
+                        break;
+                    }
+                    conversationIndex++;
+                }
+                while (messageIndex < collection.Messages.Count && conversations.Count + messages.Count < RemoteDataProtocol.MaxBatchMessages)
+                {
+                    messages.Add(collection.Messages[messageIndex]);
+                    var candidate = CreateSyncBatch(remote, account.AccountId, collection.SourceGeneration, sequence, cursorStartJson, cursorEndJson, collection.IsComplete, conversations, messages);
+                    if (JsonSerializer.SerializeToUtf8Bytes(candidate, RemoteJson.Options).LongLength > RemoteDataProtocol.MaxBatchBytes)
+                    {
+                        messages.RemoveAt(messages.Count - 1);
+                        break;
+                    }
+                    messageIndex++;
+                }
+                if (conversations.Count == 0 && messages.Count == 0)
+                    throw new WxAgentException(WxAgentErrorCode.InvalidArgument, "A single sync item exceeds the maximum batch size.");
+                var batch = CreateSyncBatch(remote, account.AccountId, collection.SourceGeneration, sequence++, cursorStartJson, cursorEndJson, collection.IsComplete, conversations, messages);
                 var queued = queue.Enqueue(reporting, batch);
                 if (!queued.Accepted || queued.Batch is null)
                 {
@@ -303,6 +319,23 @@ public sealed class RemoteAgentHostedService(
         }
     }
 
+    private static RemoteSyncBatch CreateSyncBatch(
+        RemoteAgentOptions remote,
+        string accountId,
+        string sourceGeneration,
+        long sequence,
+        string cursorStart,
+        string cursorEnd,
+        bool complete,
+        IReadOnlyList<RemoteSyncConversation> conversations,
+        IReadOnlyList<RemoteSyncMessage> messages)
+    {
+        var batch = new RemoteSyncBatch(
+            remote.NodeId!, accountId, Guid.NewGuid().ToString("N"), sourceGeneration, "messages", sequence,
+            cursorStart, cursorEnd, string.Empty, complete ? "complete" : "partial", conversations, messages);
+        return batch with { PayloadHash = RemoteDataBatchAuthorization.ComputePayloadHash(batch) };
+    }
+
     private static string SerializeCursors(IReadOnlyDictionary<string, long> cursors) =>
         JsonSerializer.Serialize(cursors.OrderBy(item => item.Key).ToDictionary(item => item.Key, item => item.Value), RemoteJson.Options);