refactor(ui/templates): extract dialog modals into shared components

src/ScadaLink.CentralUI/Components/Shared/NewFolderDialog.razor

@@ -0,0 +1,52 @@
+@if (IsVisible)
+{
+    <div class="modal show d-block" tabindex="-1" style="background: rgba(0,0,0,0.4);">
+        <div class="modal-dialog modal-sm">
+            <div class="modal-content">
+                <div class="modal-header">
+                    <h6 class="modal-title">New Folder</h6>
+                    <button type="button" class="btn-close" @onclick="Close"></button>
+                </div>
+                <div class="modal-body">
+                    <input class="form-control form-control-sm" placeholder="Folder name" @bind="_name" />
+                    @if (!string.IsNullOrEmpty(ErrorMessage)) { <div class="text-danger small mt-1">@ErrorMessage</div> }
+                </div>
+                <div class="modal-footer">
+                    <button class="btn btn-outline-secondary btn-sm" @onclick="Close">Cancel</button>
+                    <button class="btn btn-primary btn-sm" @onclick="Submit">Create</button>
+                </div>
+            </div>
+        </div>
+    </div>
+}
+
+@code {
+    [Parameter] public bool IsVisible { get; set; }
+    [Parameter] public EventCallback<bool> IsVisibleChanged { get; set; }
+    [Parameter] public int? ParentFolderId { get; set; }
+    [Parameter] public string? ErrorMessage { get; set; }
+    [Parameter] public EventCallback<(int? ParentFolderId, string Name)> OnSubmit { get; set; }
+
+    private bool _wasVisible;
+    private string _name = string.Empty;
+
+    protected override void OnParametersSet()
+    {
+        // Reset internal state on transition from hidden -> visible.
+        if (IsVisible && !_wasVisible)
+        {
+            _name = string.Empty;
+        }
+        _wasVisible = IsVisible;
+    }
+
+    private async Task Close()
+    {
+        await IsVisibleChanged.InvokeAsync(false);
+    }
+
+    private async Task Submit()
+    {
+        await OnSubmit.InvokeAsync((ParentFolderId, _name.Trim()));
+    }
+}