Add PrivilegeInputDate component with permission handling

Author: pwelter34

src/Privileged.Components/PrivilegeInputDate.cs

@@ -0,0 +1,114 @@
+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.Components.Forms;
+
+namespace Privileged.Components;
+
+/// <summary>
+/// A custom input date component that integrates privilege-based access control.
+/// </summary>
+public class PrivilegeInputDate<TValue> : InputDate<TValue>
+{
+    /// <summary>
+    /// Gets or sets the cascading privilege context used to evaluate access permissions.
+    /// </summary>
+    [CascadingParameter]
+    protected PrivilegeContext? PrivilegeContext { get; set; }
+
+    /// <summary>
+    /// Gets or sets the subject for privilege evaluation. Defaults to the model's type name if not specified.
+    /// When null, empty, or whitespace, all privileges are assumed to be granted.
+    /// </summary>
+    [Parameter]
+    public string? Subject { get; set; }
+
+    /// <summary>
+    /// Gets or sets the field qualifier for privilege evaluation. Defaults to the input's name attribute if not specified.
+    /// </summary>
+    [Parameter]
+    public string? Field { get; set; }
+
+    /// <summary>
+    /// Gets or sets the action name for read permissions. Defaults to "read".
+    /// </summary>
+    [Parameter]
+    public string ReadAction { get; set; } = "read";
+
+    /// <summary>
+    /// Gets or sets the action name for update permissions. Defaults to "update".
+    /// </summary>
+    [Parameter]
+    public string UpdateAction { get; set; } = "update";
+
+    /// <summary>
+    /// Gets a value indicating whether the user has read permission for the input.
+    /// </summary>
+    protected bool HasReadPermission { get; set; }
+
+    /// <summary>
+    /// Gets a value indicating whether the user has update permission for the input.
+    /// </summary>
+    protected bool HasUpdatePermission { get; set; }
+
+    /// <summary>
+    /// Called when the component's parameters are set. Evaluates permissions and adjusts attributes accordingly.
+    /// </summary>
+    /// <exception cref="InvalidOperationException">
+    /// Thrown if the <see cref="PrivilegeContext"/> is not provided.
+    /// </exception>
+    protected override void OnParametersSet()
+    {
+        base.OnParametersSet();
+
+        if (PrivilegeContext == null)
+            throw new InvalidOperationException("Component requires a cascading parameter of type PrivilegeContext.");
+
+        var subject = Subject ?? EditContext?.Model.GetType().Name;
+        var qualifier = Field ?? NameAttributeValue;
+
+        HasReadPermission = string.IsNullOrWhiteSpace(Subject)
+            || PrivilegeContext.Allowed(ReadAction, subject, qualifier);
+
+        HasUpdatePermission = string.IsNullOrWhiteSpace(Subject)
+            || PrivilegeContext.Allowed(UpdateAction, subject, qualifier);
+
+        if (HasUpdatePermission)
+            return;
+
+        // If no update permission, set readonly or disabled attributes
+        var attributes = AdditionalAttributes?.ToDictionary(kvp => kvp.Key, kvp => kvp.Value) ?? [];
+        if (!HasUpdatePermission)
+            attributes["readonly"] = true;
+
+        AdditionalAttributes = attributes;
+    }
+
+    /// <summary>
+    /// Builds the render tree for the component, rendering either the input or a disabled password field based on permissions.
+    /// </summary>
+    /// <param name="builder">The <see cref="Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder"/> used to build the render tree.</param>
+    protected override void BuildRenderTree(Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder builder)
+    {
+        // If the user has read permission, render the base InputText component
+        if (HasReadPermission)
+        {
+            base.BuildRenderTree(builder);
+            return;
+        }
+
+        // If the user does not have read permission, render a password input
+        builder.OpenElement(0, "input");
+        builder.AddAttribute(1, "type", "password");
+        builder.AddAttribute(2, "disabled", true);
+        builder.AddMultipleAttributes(3, AdditionalAttributes);
+
+        if (!string.IsNullOrEmpty(NameAttributeValue))
+            builder.AddAttribute(4, "name", NameAttributeValue);
+
+        if (!string.IsNullOrEmpty(CssClass))
+            builder.AddAttribute(5, "class", CssClass);
+
+        builder.AddAttribute(6, "value", CurrentValueAsString);
+        builder.AddElementReferenceCapture(7, __inputReference => Element = __inputReference);
+        builder.CloseElement();
+    }
+}