工单 增加 接收服务端推送的新工单，支持 推送增加消息

OrderSupportTicket/ViewModels/OrderSupportTicketViewModel.cs

@@ -42,6 +42,7 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
     private readonly AsyncDelegateCommand _sendMessageCommand;
     private readonly AsyncDelegateCommand<PendingAttachmentViewModel> _removePendingAttachmentCommand;
     private readonly AsyncDelegateCommand _loadEarlierMessagesCommand;
+    private readonly AsyncDelegateCommand _refreshMessagesCommand;
     private readonly AsyncDelegateCommand _retryRealtimeCommand;
 	private readonly DelegateCommand<FrameworkElement> _addImagesCommand;
     private readonly HashSet<string> _seenEventIds =
@@ -50,6 +51,12 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
         new Dictionary<string, int>(StringComparer.Ordinal);
     private Dictionary<string, WorkOrderListCacheItem> _savedWorkOrders =
         new Dictionary<string, WorkOrderListCacheItem>(StringComparer.Ordinal);
+    // 按 APPID 和订单号隔离各工单消息，切换会话不丢失推送。
+    private readonly Dictionary<string, Dictionary<string, TicketMessageDto>> _conversationMessages =
+        new Dictionary<string, Dictionary<string, TicketMessageDto>>(StringComparer.Ordinal);
+    private readonly Dictionary<string, WorkOrderMessagesResponse> _conversationPages = new Dictionary<string, WorkOrderMessagesResponse>(StringComparer.Ordinal);
+    private readonly Dictionary<string, Task> _conversationLoads = new Dictionary<string, Task>(StringComparer.Ordinal);
+    private bool IsRealtimeConversation => _options?.ConversationMode == TicketConversationMode.Realtime;
     private bool _hasSavedCache;
     private TicketClientOptions _options;
     private bool _configured;
@@ -114,6 +121,9 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
         _loadEarlierMessagesCommand = new AsyncDelegateCommand(
             LoadEarlierMessagesAsync,
             () => !IsBusy && SelectedTicket != null && HasMoreMessages);
+        _refreshMessagesCommand = new AsyncDelegateCommand(
+            RefreshMessagesAsync,
+            () => _configured && !IsBusy && !IsLoadingMessages && !IsDraft && SelectedTicket != null);
         _retryRealtimeCommand = new AsyncDelegateCommand(
             RestartRealtimeAsync,
             () => _configured);
@@ -198,6 +208,9 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
     /// </summary>
     public ICommand LoadEarlierMessagesCommand => _loadEarlierMessagesCommand;
 
+    /// <summary>强制重新获取当前工单消息，两种会话模式均不使用缓存代替请求。</summary>
+    public ICommand RefreshMessagesCommand => _refreshMessagesCommand;
+
     /// <summary>
     /// 手动重新连接 SSE 的命令。
     /// </summary>
@@ -377,7 +390,11 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
     public bool IsLoadingMessages
     {
         get => _isLoadingMessages;
-        private set => SetValue(ref _isLoadingMessages, value);
+        private set
+        {
+            if (SetValue(ref _isLoadingMessages, value))
+                _refreshMessagesCommand.RaiseCanExecuteChanged();
+        }
     }
 
     /// <summary>
@@ -865,6 +882,11 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
         _initialized = false;
         _pendingOpenKey = null;
         _options = CloneOptions(options);
+        _conversationMessages.Clear();
+        _conversationPages.Clear();
+        _conversationLoads.Clear();
+        _seenEventIds.Clear();
+        _lastReadSequences.Clear();
         HasNewData = false;
         NewDataText = string.Empty;
 
@@ -943,6 +965,7 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
 
             if (!_initialized || started)
             {
+                // 会话模式不改变初始化列表和历史对话加载流程。
                 await RefreshAllWorkOrdersAsync(loadSelectedMessages: true);
                 _initialized = true;
             }
@@ -1272,7 +1295,10 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
                 receipts);
 
             if (result.Message != null)
-                AppendMessage(result.Message);
+            {
+                RememberMessage(ticket.Key, result.Message);
+                MergeMessages(new[] { result.Message });
+            }
             ticket.ApplySendResult(result.Status, result.Version);
             MoveTicketToTop(ticket);
             TicketView.Refresh();
@@ -1337,6 +1363,36 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
         }
     }
 
+    private async Task RefreshMessagesAsync()
+    {
+        var ticket = SelectedTicket;
+        if (!_configured || IsBusy || IsLoadingMessages || IsDraft || ticket == null)
+            return;
+
+        var options = _options;
+        IsBusy = true;
+        IsLoadingMessages = true;
+        ClearNotice();
+        try
+        {
+            await FetchConversationAsync(ticket.AppId, ticket.WechatOrderId, force: true);
+            if (_disposed || !ReferenceEquals(options, _options)
+                || IsDraft || SelectedTicket?.Key != ticket.Key)
+                return;
+            ShowCachedConversation(SelectedTicket);
+            await MarkReadBestEffortAsync(SelectedTicket);
+        }
+        catch (Exception ex)
+        {
+            SetNotice("刷新工单消息失败：" + DescribeException(ex), true);
+        }
+        finally
+        {
+            IsLoadingMessages = false;
+            IsBusy = false;
+        }
+    }
+
     private async Task LoadEarlierMessagesAsync()
     {
         var ticket = SelectedTicket;
@@ -1352,6 +1408,9 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
                 ticket.WechatOrderId,
                 _nextBefore,
                 50);
+            foreach (var message in response.Items ?? new List<TicketMessageDto>())
+                RememberMessage(ticket.Key, message);
+            _conversationPages[ticket.Key] = response;
             MergeMessages(response.Items ?? new List<TicketMessageDto>());
             HasMoreMessages = response.HasMore;
             _nextBefore = response.NextBefore;
@@ -1398,41 +1457,82 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
         IsLoadingMessages = true;
         try
         {
-            var response = await _ticketService.GetMessagesAsync(
-                _options,
-                ticket.AppId,
-                ticket.WechatOrderId,
-                null,
-                50);
-            if (version != _selectionVersion
-                || SelectedTicket == null
-                || !string.Equals(ticket.Key, SelectedTicket.Key, StringComparison.Ordinal))
-            {
+            // 点击工单始终可读取历史，Realtime 模式复用已加载的会话。
+            if (!IsRealtimeConversation || !_conversationMessages.ContainsKey(ticket.Key))
+                await FetchConversationAsync(ticket.AppId, ticket.WechatOrderId, force: !IsRealtimeConversation);
+            if (version != _selectionVersion || SelectedTicket?.Key != ticket.Key || IsDraft)
                 return;
-            }
-
-            if (replace)
-                Messages.Clear();
-            MergeMessages(response.Items ?? new List<TicketMessageDto>());
-            HasMoreMessages = response.HasMore;
-            _nextBefore = response.NextBefore;
+            ShowCachedConversation(ticket);
             await MarkReadBestEffortAsync(ticket);
-            MessageScrollVersion++;
         }
         catch (Exception ex)
         {
-            if (replace)
-                Messages.Clear();
-            HasMoreMessages = false;
-            _nextBefore = null;
-            SetNotice(DescribeException(ex), true);
+            if (version == _selectionVersion)
+            {
+                if (replace) Messages.Clear();
+                HasMoreMessages = false;
+                _nextBefore = null;
+                SetNotice(DescribeException(ex), true);
+            }
         }
         finally
         {
-            IsLoadingMessages = false;
+            if (version == _selectionVersion)
+                IsLoadingMessages = false;
         }
     }
 
+    private async Task FetchConversationAsync(string appId, string orderId, bool force = false)
+    {
+        var key = appId + "|" + orderId;
+        if (_conversationLoads.TryGetValue(key, out var loading))
+        {
+            await loading;
+            if (!force) return;
+        }
+        var task = FetchConversationCoreAsync(appId, orderId);
+        _conversationLoads[key] = task;
+        try { await task; }
+        finally
+        {
+            if (_conversationLoads.TryGetValue(key, out var current) && ReferenceEquals(current, task))
+                _conversationLoads.Remove(key);
+        }
+    }
+
+    private async Task FetchConversationCoreAsync(string appId, string orderId)
+    {
+        var options = _options;
+        var key = appId + "|" + orderId;
+        var before = _conversationMessages.TryGetValue(key, out var existing)
+            ? new Dictionary<string, TicketMessageDto>(existing, StringComparer.Ordinal) : null;
+        var response = await _ticketService.GetMessagesAsync(options, appId, orderId, null, 50);
+        if (_disposed || !ReferenceEquals(options, _options)) return;
+        // 刷新历史期间收到的增量不能被较早的接口快照覆盖。
+        var addedDuringLoad = before != null && _conversationMessages.TryGetValue(key, out var latest)
+            ? latest.Where(pair => !before.TryGetValue(pair.Key, out var old)
+                || !ReferenceEquals(old, pair.Value)).Select(pair => pair.Value).ToList()
+            : new List<TicketMessageDto>();
+        // 只在历史请求成功后建立缓存；首次推送触发的历史已包含该消息，不再追加。
+        _conversationMessages[key] = new Dictionary<string, TicketMessageDto>(StringComparer.Ordinal);
+        foreach (var message in response.Items ?? new List<TicketMessageDto>())
+            RememberMessage(key, message);
+        foreach (var message in addedDuringLoad)
+            RememberMessage(key, message);
+        _conversationPages[key] = response;
+    }
+
+    private void ShowCachedConversation(WorkOrderSummaryViewModel ticket)
+    {
+        Messages.Clear();
+        if (_conversationMessages.TryGetValue(ticket.Key, out var cached))
+            MergeMessages(cached.Values);
+        _conversationPages.TryGetValue(ticket.Key, out var page);
+        HasMoreMessages = page?.HasMore ?? false;
+        _nextBefore = page?.NextBefore;
+        MessageScrollVersion++;
+    }
+
     private async Task RefreshAllWorkOrdersAsync(
         bool loadSelectedMessages,
         string preferredKey = null)
@@ -1471,8 +1571,8 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
                 var hasNewMessage = HasNewMessage(dto);
                 if (existing.TryGetValue(key, out var item))
                 {
-                    if (!item.TryApply(dto))
-                        continue;
+                    // 查询期间可能先收到更新的 SSE，保留较新摘要，不能丢掉该工单。
+                    item.TryApply(dto);
                 }
                 else
                 {
@@ -1498,7 +1598,15 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
             SaveWorkOrderList();
 
             if (loadSelectedMessages && SelectedTicket != null && !IsDraft)
-                await LoadMessagesAsync(SelectedTicket, replace: true);
+            {
+                var selected = SelectedTicket;
+                await FetchConversationAsync(selected.AppId, selected.WechatOrderId, force: true);
+                if (!IsDraft && SelectedTicket?.Key == selected.Key)
+                {
+                    ShowCachedConversation(selected);
+                    await MarkReadBestEffortAsync(selected);
+                }
+            }
         }
         catch (Exception ex)
         {
@@ -1579,26 +1687,6 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
             Messages.Add(message);
     }
 
-    private void AppendMessage(TicketMessageDto dto)
-    {
-        if (dto == null)
-            return;
-        var id = string.IsNullOrWhiteSpace(dto.MessageId)
-            ? "sequence:" + dto.SequenceNo
-            : dto.MessageId;
-        if (Messages.Any(m => string.Equals(m.MessageId, id, StringComparison.Ordinal)))
-            return;
-
-        var incoming = new ChatMessageViewModel(dto);
-        var index = 0;
-        while (index < Messages.Count
-               && Messages[index].SequenceNo <= incoming.SequenceNo)
-        {
-            index++;
-        }
-        Messages.Insert(index, incoming);
-    }
-
     private async Task MarkReadBestEffortAsync(WorkOrderSummaryViewModel ticket)
     {
         if (!_isWindowActive || ticket == null)
@@ -1680,21 +1768,33 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
 
         try
         {
-            if (notification.IsResyncRequired)
+            if (notification.IsResyncRequired
+                || string.Equals(notification.Type, "relay.ticket.created", StringComparison.OrdinalIgnoreCase))
             {
-                await RefreshAllWorkOrdersAsync(
-                    loadSelectedMessages: SelectedTicket != null && !IsDraft);
+                // 刷新后仍恢复当前工单，不能自动切换到新工单。
+                await RefreshAllWorkOrdersAsync(loadSelectedMessages: true);
+                var created = FindTicket(notification.AppId + "|" + notification.WechatOrderId);
+                if (created != null && !notification.IsResyncRequired) MoveTicketToTop(created);
                 return;
             }
-
             if (string.IsNullOrWhiteSpace(notification.AppId)
-                || string.IsNullOrWhiteSpace(notification.WechatOrderId))
+                || string.IsNullOrWhiteSpace(notification.WechatOrderId)
+                || !_options.AppIds.Contains(notification.AppId)) return;
+
+            if (IsRealtimeConversation)
+                await ApplyRealtimeNotificationAsync(notification);
+            else
             {
-                return;
+                // History 保持原有查询摘要、刷新当前对话的流程。
+                var ticket = FindTicket(notification.AppId + "|" + notification.WechatOrderId);
+                var unreadCount = (ticket?.UnreadCount ?? 0) + 1;
+                ticket?.EnsureUnreadCount(unreadCount);
+                await RefreshSingleWorkOrderAsync(notification.AppId, notification.WechatOrderId);
+                ticket = FindTicket(notification.AppId + "|" + notification.WechatOrderId);
+                if (ticket != null && (SelectedTicket?.Key != ticket.Key || !_isWindowActive))
+                    ticket.EnsureUnreadCount(unreadCount);
+                SaveWorkOrderList();
             }
-            await RefreshSingleWorkOrderAsync(
-                notification.AppId,
-                notification.WechatOrderId);
         }
         catch (Exception ex)
         {
@@ -1702,6 +1802,64 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
         }
     }
 
+    private void RememberMessage(string key, TicketMessageDto message, bool preserveExisting = false)
+    {
+        if (message == null)
+            return;
+        if (!_conversationMessages.TryGetValue(key, out var messages))
+            _conversationMessages[key] = messages = new Dictionary<string, TicketMessageDto>(StringComparer.Ordinal);
+        var id = string.IsNullOrWhiteSpace(message.MessageId)
+            ? "sequence:" + message.SequenceNo : message.MessageId;
+        if (!preserveExisting || !messages.ContainsKey(id))
+            messages[id] = message;
+    }
+
+    private async Task ApplyRealtimeNotificationAsync(TicketRealtimeNotification notification)
+    {
+        var key = notification.AppId + "|" + notification.WechatOrderId;
+        var ticket = FindTicket(key);
+        // 未加载过会话：获取历史，推送消息不再额外插入。
+        if (!_conversationMessages.TryGetValue(key, out var cached))
+        {
+            await FetchConversationAsync(notification.AppId, notification.WechatOrderId);
+            ticket?.MarkHasNewMessage();
+            if (!IsDraft && SelectedTicket?.Key == key)
+            {
+                ShowCachedConversation(SelectedTicket);
+                await MarkReadBestEffortAsync(SelectedTicket);
+            }
+            SaveWorkOrderList();
+            return;
+        }
+        var message = notification.Message;
+        if (message == null) return;
+        var id = string.IsNullOrWhiteSpace(message.MessageId) ? "sequence:" + message.SequenceNo : message.MessageId;
+        var isNew = !cached.ContainsKey(id);
+        RememberMessage(key, message);
+        if (notification.Ticket != null && ticket != null)
+        {
+            var dto = notification.Ticket;
+            dto.AppId = notification.AppId;
+            dto.WechatOrderId = notification.WechatOrderId;
+            dto.Version = dto.Version ?? notification.Version;
+            dto.LastMessageAt = message.CreatedAt;
+            dto.LastSenderType = message.SenderType;
+            dto.UnreadCount = ticket.UnreadCount;
+            ticket.TryApply(dto);
+        }
+        if (isNew) ticket?.IncrementUnreadCount();
+        if (!IsDraft && SelectedTicket?.Key == key)
+        {
+            var existing = Messages.FirstOrDefault(m => m.MessageId == id);
+            if (existing != null) existing.UpdateFrom(message);
+            else Messages.Add(new ChatMessageViewModel(message));
+            MessageScrollVersion++;
+            await MarkReadBestEffortAsync(SelectedTicket);
+        }
+        TicketView.Refresh();
+        SaveWorkOrderList();
+    }
+
     private void OnRealtimeStateChanged(
         object sender,
         TicketRealtimeStateChangedEventArgs args)
@@ -1801,6 +1959,7 @@ public sealed class OrderSupportTicketViewModel : BindableBaseEx, IDialogAware,
     private void RaiseLoadEarlierCanExecuteChanged()
     {
         _loadEarlierMessagesCommand.RaiseCanExecuteChanged();
+        _refreshMessagesCommand.RaiseCanExecuteChanged();
     }
 
     private void SetNotice(string text, bool isError)