feat(centralui): tree rendering + lazy load + selection in OpcUaBrowserDialog

src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Dialogs/OpcUaBrowserDialog.razor

@@ -22,7 +22,19 @@
                     }
 
                     <div class="opcua-browser-tree">
-                        <!-- Task 16 fills this in -->
+                        @if (_rootNodes.Count == 0 && _failure is null)
+                        {
+                            <em class="text-muted">Loading…</em>
+                        }
+                        else
+                        {
+                            <ul class="list-unstyled mb-0">
+                                @foreach (var node in _rootNodes)
+                                {
+                                    <TreeRow Node="node" OnToggle="ToggleAsync" OnSelect="Select" SelectedNodeId="@_selectedNodeId" />
+                                }
+                            </ul>
+                        }
                     </div>
 
                     <hr />
@@ -56,6 +68,28 @@
     private string _manualNodeId = "";
     private BrowseFailure? _failure;
     private string _failureMessage = "";
+    private List<TreeNode> _rootNodes = new();
+
+    public sealed class TreeNode
+    {
+        public TreeNode(string nodeId, string displayName, BrowseNodeClass nodeClass, bool hasChildren)
+        {
+            NodeId = nodeId;
+            DisplayName = displayName;
+            NodeClass = nodeClass;
+            HasChildren = hasChildren;
+        }
+
+        public string NodeId { get; }
+        public string DisplayName { get; }
+        public BrowseNodeClass NodeClass { get; }
+        public bool HasChildren { get; }
+
+        public List<TreeNode>? Children { get; set; }   // null = not loaded yet
+        public bool Expanded { get; set; }
+        public bool Loading { get; set; }
+        public bool Truncated { get; set; }
+    }
 
     public async Task ShowAsync()
     {
@@ -67,7 +101,66 @@
 
     private async Task LoadRootAsync()
     {
-        // Task 16
+        _failure = null;
+        _rootNodes = new();
+        StateHasChanged();
+
+        var result = await BrowseService.BrowseChildrenAsync(SiteId, DataConnectionId, parentNodeId: null);
+        if (result.Failure is not null)
+        {
+            SetFailure(result.Failure);
+            return;
+        }
+
+        _rootNodes = result.Children.Select(c => new TreeNode(c.NodeId, c.DisplayName, c.NodeClass, c.HasChildren)).ToList();
+        StateHasChanged();
+    }
+
+    private async Task ToggleAsync(TreeNode node)
+    {
+        if (!node.HasChildren) return;
+
+        if (node.Expanded)
+        {
+            node.Expanded = false;
+            return;
+        }
+
+        if (node.Children is null)
+        {
+            node.Loading = true;
+            StateHasChanged();
+            var result = await BrowseService.BrowseChildrenAsync(SiteId, DataConnectionId, node.NodeId);
+            node.Loading = false;
+
+            if (result.Failure is not null)
+            {
+                SetFailure(result.Failure);
+                return;
+            }
+
+            node.Children = result.Children
+                .Select(c => new TreeNode(c.NodeId, c.DisplayName, c.NodeClass, c.HasChildren))
+                .ToList();
+            node.Truncated = result.Truncated;
+        }
+
+        node.Expanded = true;
+    }
+
+    private void Select(TreeNode node)
+    {
+        if (node.NodeClass != BrowseNodeClass.Variable) return;
+        _selectedNodeId = node.NodeId;
+        _manualNodeId = node.NodeId;
+    }
+
+    // NOTE: Task 17 will replace this body with the full BrowseFailureKind switch
+    //       that maps each failure kind to a friendly UI message.
+    private void SetFailure(BrowseFailure failure)
+    {
+        _failure = failure;
+        _failureMessage = failure.Message;
     }
 
     private Task RetryRootLoad() => LoadRootAsync();

src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Dialogs/TreeRow.razor

@@ -0,0 +1,53 @@
+@using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Protocol
+<li>
+    <span style="cursor: @(Node.HasChildren ? "pointer" : "default");" @onclick="() => OnToggle.InvokeAsync(Node)">
+        @if (Node.HasChildren)
+        {
+            <span>@(Node.Expanded ? "▼" : "▶")</span>
+        }
+        else
+        {
+            <span style="display:inline-block; width:1em;">&nbsp;</span>
+        }
+    </span>
+
+    @if (Node.NodeClass == BrowseNodeClass.Variable)
+    {
+        <a href="javascript:void(0)"
+           class="@(Node.NodeId == SelectedNodeId ? "fw-bold text-primary" : "")"
+           @onclick="() => OnSelect.InvokeAsync(Node)"
+           @ondblclick="() => OnSelect.InvokeAsync(Node)">
+            @Node.DisplayName <small class="text-muted">(@Node.NodeId)</small>
+        </a>
+    }
+    else
+    {
+        <span class="text-muted">@Node.DisplayName</span>
+    }
+
+    @if (Node.Loading)
+    {
+        <em class="ms-2 text-muted">loading…</em>
+    }
+
+    @if (Node.Expanded && Node.Children is not null)
+    {
+        <ul class="list-unstyled ms-4">
+            @foreach (var child in Node.Children)
+            {
+                <TreeRow Node="child" OnToggle="OnToggle" OnSelect="OnSelect" SelectedNodeId="@SelectedNodeId" />
+            }
+            @if (Node.Truncated)
+            {
+                <li><small class="text-warning">Results truncated — use manual entry if your tag isn't listed.</small></li>
+            }
+        </ul>
+    }
+</li>
+
+@code {
+    [Parameter] public OpcUaBrowserDialog.TreeNode Node { get; set; } = default!;
+    [Parameter] public EventCallback<OpcUaBrowserDialog.TreeNode> OnToggle { get; set; }
+    [Parameter] public EventCallback<OpcUaBrowserDialog.TreeNode> OnSelect { get; set; }
+    [Parameter] public string? SelectedNodeId { get; set; }
+}