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 * OPC Foundation MIT License 1.00
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using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Moq;
using NUnit.Framework;

namespace Opc.Ua.Server.Tests
{
    /// <summary>
    /// Focused tests for the permission gate added to
    /// <see cref="EventManager.ReportEventAsync"/> (closes the
    /// permission bypass in the legacy
    /// <c>EventManager.ReportEvent(IFilterTarget, IList&lt;IEventMonitoredItem&gt;)</c>
    /// overload).
    /// </summary>
    [TestFixture]
    [Category("EventManager")]
    [SetCulture("en-us")]
    [SetUICulture("en-us")]
    [Parallelizable]
    public class EventManagerReportEventAsyncTests
    {
        [TestCase(false)]
        [TestCase(true)]
        public async Task OneFailingReceiverDoesNotDiscardLaterEventsAsync(bool permissionFailure)
        {
            var owner = new Mock<IAsyncNodeManager>();
            owner.Setup(value => value.ValidateEventRolePermissionsAsync(
                    It.IsAny<IEventMonitoredItem>(), It.IsAny<IFilterTarget>(), It.IsAny<CancellationToken>()))
                .Returns(new ValueTask<ServiceResult>(ServiceResult.Good));
            var failing = new Mock<IEventMonitoredItem>();
            var following = new Mock<IEventMonitoredItem>();
            if (permissionFailure)
            {
                owner.Setup(value => value.ValidateEventRolePermissionsAsync(
                        failing.Object, It.IsAny<IFilterTarget>(), It.IsAny<CancellationToken>()))
                    .ThrowsAsync(new InvalidOperationException("permission lookup failed"));
            }
            else
            {
                failing.Setup(value => value.QueueEvent(It.IsAny<IFilterTarget>()))
                    .Callback<IFilterTarget>(filter => throw new ArgumentNullException(nameof(filter)));
            }
            var occurrence = new BaseEventState(null);

            await EventManager.ReportEventAsync(occurrence, owner.Object, [failing.Object, following.Object])
                .ConfigureAwait(false);

            following.Verify(value => value.QueueEvent(occurrence), Times.Once);
        }

        [Test]
        public void ReportEventCancellationStillStopsDispatch()
        {
            var owner = new Mock<IAsyncNodeManager>();
            var receiver = new Mock<IEventMonitoredItem>();
            using var cancellation = new CancellationTokenSource();
            cancellation.Cancel();

            Assert.ThrowsAsync<OperationCanceledException>(async () =>
                await EventManager.ReportEventAsync(
                    new BaseEventState(null), owner.Object, [receiver.Object], cancellation.Token)
                    .ConfigureAwait(false));

            receiver.Verify(value => value.QueueEvent(It.IsAny<IFilterTarget>()), Times.Never);
        }

        /// <summary>
        /// When the node manager grants <c>ReceiveEvents</c>, the event is
        /// queued on every supplied item.
        /// </summary>
        [Test]
        public async Task ReportEventAsync_WithPermission_QueuesToAllItems()
        {
            var nodeManagerMock = new Mock<IAsyncNodeManager>();
            nodeManagerMock
                .Setup(m => m.ValidateEventRolePermissionsAsync(
                    It.IsAny<IEventMonitoredItem>(),
                    It.IsAny<IFilterTarget>(),
                    It.IsAny<CancellationToken>()))
                .Returns(new ValueTask<ServiceResult>(ServiceResult.Good));

            var item1 = new Mock<IEventMonitoredItem>();
            item1.Setup(m => m.Id).Returns(1u);
            var item2 = new Mock<IEventMonitoredItem>();
            item2.Setup(m => m.Id).Returns(2u);

            IList<IEventMonitoredItem> receivers = [item1.Object, item2.Object];
            var ev = new BaseEventState(null);

            await EventManager.ReportEventAsync(ev, nodeManagerMock.Object, receivers).ConfigureAwait(false);

            item1.Verify(m => m.QueueEvent(ev), Times.Once);
            item2.Verify(m => m.QueueEvent(ev), Times.Once);
        }

        /// <summary>
        /// When the node manager denies <c>ReceiveEvents</c>, the event is
        /// dropped silently — no item receives a queue call.
        /// </summary>
        [Test]
        public async Task ReportEventAsync_WithoutPermission_DropsEvent()
        {
            var nodeManagerMock = new Mock<IAsyncNodeManager>();
            nodeManagerMock
                .Setup(m => m.ValidateEventRolePermissionsAsync(
                    It.IsAny<IEventMonitoredItem>(),
                    It.IsAny<IFilterTarget>(),
                    It.IsAny<CancellationToken>()))
                .Returns(new ValueTask<ServiceResult>(new ServiceResult(StatusCodes.BadUserAccessDenied)));

            var item = new Mock<IEventMonitoredItem>();
            item.Setup(m => m.Id).Returns(1u);

            IList<IEventMonitoredItem> receivers = [item.Object];
            var ev = new BaseEventState(null);

            await EventManager.ReportEventAsync(ev, nodeManagerMock.Object, receivers).ConfigureAwait(false);

            item.Verify(m => m.QueueEvent(It.IsAny<IFilterTarget>()), Times.Never);
        }

        /// <summary>
        /// The gate is evaluated per item, so a mixed-permission set still
        /// delivers to the permitted item only.
        /// </summary>
        [Test]
        public async Task ReportEventAsync_MixedPermissions_DeliversOnlyToPermittedItem()
        {
            var permittedItem = new Mock<IEventMonitoredItem>();
            permittedItem.Setup(m => m.Id).Returns(1u);
            var deniedItem = new Mock<IEventMonitoredItem>();
            deniedItem.Setup(m => m.Id).Returns(2u);

            var nodeManagerMock = new Mock<IAsyncNodeManager>();
            nodeManagerMock
                .Setup(m => m.ValidateEventRolePermissionsAsync(
                    permittedItem.Object,
                    It.IsAny<IFilterTarget>(),
                    It.IsAny<CancellationToken>()))
                .Returns(new ValueTask<ServiceResult>(ServiceResult.Good));
            nodeManagerMock
                .Setup(m => m.ValidateEventRolePermissionsAsync(
                    deniedItem.Object,
                    It.IsAny<IFilterTarget>(),
                    It.IsAny<CancellationToken>()))
                .Returns(new ValueTask<ServiceResult>(new ServiceResult(StatusCodes.BadUserAccessDenied)));

            IList<IEventMonitoredItem> receivers = [permittedItem.Object, deniedItem.Object];
            var ev = new BaseEventState(null);

            await EventManager.ReportEventAsync(ev, nodeManagerMock.Object, receivers).ConfigureAwait(false);

            permittedItem.Verify(m => m.QueueEvent(ev), Times.Once);
            deniedItem.Verify(m => m.QueueEvent(It.IsAny<IFilterTarget>()), Times.Never);
        }

        /// <summary>
        /// An Uncertain verdict is not a denial, so the event must still be delivered.
        /// </summary>
        [Test]
        public async Task ReportEventAsync_WithUncertainPermission_StillQueuesEventAsync(
            [ValueSource(nameof(UncertainStatusCodes))] StatusCode statusCode)
        {
            var nodeManagerMock = new Mock<IAsyncNodeManager>();
            nodeManagerMock
                .Setup(m => m.ValidateEventRolePermissionsAsync(
                    It.IsAny<IEventMonitoredItem>(),
                    It.IsAny<IFilterTarget>(),
                    It.IsAny<CancellationToken>()))
                .Returns(new ValueTask<ServiceResult>(new ServiceResult(statusCode)));

            var item = new Mock<IEventMonitoredItem>();
            item.Setup(m => m.Id).Returns(1u);

            IList<IEventMonitoredItem> receivers = [item.Object];
            var ev = new BaseEventState(null);

            await EventManager.ReportEventAsync(ev, nodeManagerMock.Object, receivers).ConfigureAwait(false);

            Assert.That(StatusCode.IsUncertain(statusCode), Is.True);
            item.Verify(m => m.QueueEvent(ev), Times.Once);
        }

        private static StatusCode[] UncertainStatusCodes =>
        [
            StatusCodes.UncertainNotAllNodesAvailable,
            StatusCodes.UncertainReferenceOutOfServer
        ];
    }
}