dashboard: lazy-load BrowsePage via DashboardBrowseService

src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/BrowsePage.razor

@@ -2,6 +2,8 @@
 @implements IAsyncDisposable
 @inject IGalaxyHierarchyCache GalaxyCache
 @inject IDashboardLiveDataService LiveData
+@inject IDashboardBrowseService BrowseService
+@inject IGalaxyDeployNotifier DeployNotifier
 @using ZB.MOM.WW.MxGateway.Contracts.Proto.Galaxy
 @using ZB.MOM.WW.MxGateway.Server.Galaxy
 
@@ -71,12 +73,18 @@
         }
         else
         {
+            @if (!string.IsNullOrEmpty(_staleBanner))
+            {
+                <div class="alert alert-info browse-stale-banner" role="status"
+                     @onclick="ClearStaleBanner">@_staleBanner</div>
+            }
             <div class="browse-tree">
                 @foreach (DashboardBrowseNode root in _roots)
                 {
                     <BrowseTreeNodeView Node="root"
                                         OnAddTag="AddTagAsync"
-                                        OnTagContextMenu="OnTagContextMenu" />
+                                        OnTagContextMenu="OnTagContextMenu"
+                                        OnLoadChildren="LoadChildrenAsync" />
                 }
             </div>
             <div class="browse-search-note">Double-click a tag, or right-click for the menu.</div>
@@ -186,7 +194,11 @@
 @code {
     private const int SearchResultLimit = 300;
 
-    private IReadOnlyList<DashboardBrowseNode> _roots = [];
+    private List<DashboardBrowseNode> _roots = [];
+    private ulong _cacheSequence;
+    private string? _staleBanner;
+    private CancellationTokenSource _deployCts = new();
+    private Task? _deployTask;
     private string _search = string.Empty;
     private IReadOnlyList<GalaxyAttribute> _searchMatches = [];
     private readonly List<string> _subscribed = [];
@@ -210,8 +222,58 @@
     /// <inheritdoc />
     protected override void OnInitialized()
     {
-        _roots = DashboardBrowseTreeBuilder.Build(GalaxyCache.Current.Objects);
+        BrowseLevelResult roots = BrowseService.GetRoots(new BrowseFilterArgs());
+        _roots = [.. roots.Nodes];
+        _cacheSequence = roots.CacheSequence;
         _pollTask = PollLoopAsync();
+        _deployTask = SubscribeToDeployEventsAsync();
+    }
+
+    private async Task LoadChildrenAsync(DashboardBrowseNode node)
+    {
+        BrowseLevelResult result = BrowseService.GetChildren(node.Object.GobjectId, new BrowseFilterArgs());
+        node.Children.Clear();
+        foreach (DashboardBrowseNode child in result.Nodes)
+        {
+            node.Children.Add(child);
+        }
+
+        // First expand interaction also dismisses the stale banner — the user
+        // is clearly engaging with the tree, no need to keep nagging.
+        _staleBanner = null;
+        await InvokeAsync(StateHasChanged);
+    }
+
+    private async Task SubscribeToDeployEventsAsync()
+    {
+        try
+        {
+            await foreach (GalaxyDeployEventInfo info in DeployNotifier
+                .SubscribeAsync(_deployCts.Token)
+                .ConfigureAwait(false))
+            {
+                // First Latest replay echoes the sequence we already projected
+                // from — skip those to avoid a spurious "redeployed" banner.
+                if (info.Sequence == 0 || (ulong)info.Sequence == _cacheSequence)
+                {
+                    continue;
+                }
+
+                BrowseLevelResult roots = BrowseService.GetRoots(new BrowseFilterArgs());
+                _roots = [.. roots.Nodes];
+                _cacheSequence = roots.CacheSequence;
+                _staleBanner = "Galaxy redeployed — tree refreshed.";
+                await InvokeAsync(StateHasChanged);
+            }
+        }
+        catch (OperationCanceledException)
+        {
+        }
+    }
+
+    private void ClearStaleBanner()
+    {
+        _staleBanner = null;
     }
 
     private string HeaderLine()
@@ -405,6 +467,7 @@
     public async ValueTask DisposeAsync()
     {
         await _cts.CancelAsync();
+        await _deployCts.CancelAsync();
         if (_pollTask is not null)
         {
             try
@@ -415,8 +478,19 @@
             {
             }
         }
+        if (_deployTask is not null)
+        {
+            try
+            {
+                await _deployTask;
+            }
+            catch (OperationCanceledException)
+            {
+            }
+        }
 
         _cts.Dispose();
+        _deployCts.Dispose();
         GC.SuppressFinalize(this);
     }
 }