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 * Copyright (c) 2005-2025 The OPC Foundation, Inc. All rights reserved.
 *
 * OPC Foundation MIT License 1.00
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
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 *
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 * OTHER DEALINGS IN THE SOFTWARE.
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 * http://opcfoundation.org/License/MIT/1.00/
 * ======================================================================*/

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Moq;
using NUnit.Framework;
using Opc.Ua.Client.Subscriptions;
using Opc.Ua.Client.Subscriptions.Engine;
using Opc.Ua.Tests;

// CA2000: test code; many disposables are ownership-transferred to test fixtures or short-lived,
// making CA2000 noisy without a real leak risk. Disabled file-level for the suite (the existing
// narrow-scope pragma below at line ~163 predates the file-level decision).
#pragma warning disable CA2000

namespace Opc.Ua.Client.Tests
{
    [TestFixture]
    [Parallelizable]
    [Category("Client")]
    [Category("DefaultSubscriptionEngine")]
    public class DefaultSubscriptionEngineTests
    {
        private ITelemetryContext m_telemetry;
        private Mock<ISubscriptionEngineContext> m_mockContext;

        [SetUp]
        public void SetUp()
        {
            m_telemetry = NUnitTelemetryContext.Create();

            m_mockContext = new Mock<ISubscriptionEngineContext>();
            m_mockContext
                .Setup(c => c.SessionId)
                .Returns(new NodeId(1));
            m_mockContext
                .Setup(c => c.Disposed)
                .Returns(false);
            m_mockContext
                .Setup(c => c.Reconnecting)
                .Returns(false);
            m_mockContext
                .Setup(c => c.Connected)
                .Returns(false);
            m_mockContext
                .Setup(c => c.Closing)
                .Returns(false);
            m_mockContext
                .Setup(c => c.Telemetry)
                .Returns(m_telemetry);
            m_mockContext
                .Setup(c => c.OperationTimeout)
                .Returns(60000);
            m_mockContext
                .Setup(c => c.ReturnDiagnostics)
                .Returns(DiagnosticsMasks.None);
            m_mockContext
                .Setup(c => c.ReconnectLock)
                .Returns(new SemaphoreSlim(1, 1));
            m_mockContext
                .Setup(c => c.GoodPublishRequestCount)
                .Returns(0);
#if OPCUA_V1_CLIENT
            m_mockContext
                .Setup(c => c.Subscriptions)
                .Returns(new List<Subscription>());
#endif
        }

        [Test]
        public void FactoryCreateReturnsV2Engine()
        {
            ISubscriptionEngine engine =
                DefaultSubscriptionEngineFactory.Instance.Create(
                    m_mockContext.Object);

            Assert.That(engine, Is.Not.Null);
            Assert.That(
                engine,
                Is.InstanceOf<DefaultSubscriptionEngine>());

            engine.Dispose();
        }

        [Test]
        public void FactoryInstanceIsSingleton()
        {
            DefaultSubscriptionEngineFactory first =
                DefaultSubscriptionEngineFactory.Instance;
            DefaultSubscriptionEngineFactory second =
                DefaultSubscriptionEngineFactory.Instance;

            Assert.That(first, Is.SameAs(second));
        }

        [Test]
        public void ConstructorThrowsOnNullContext()
        {
            Assert.That(
                () => new DefaultSubscriptionEngine(null!),
                Throws.TypeOf<ArgumentNullException>());
        }

        [Test]
        public void SubscriptionContextReportsRevisedSessionTimeout()
        {
            m_mockContext
                .Setup(c => c.OperationTimeout)
                .Returns(120000);
            m_mockContext
                .Setup(c => c.SessionTimeout)
                .Returns(60000);

            var context =
                new DefaultSubscriptionEngine.SubscriptionContextAdapter(
                    m_mockContext.Object);

            Assert.That(
                context.SessionTimeout,
                Is.EqualTo(TimeSpan.FromSeconds(60)));
        }

        [TestCase(0.0)]
        [TestCase(-1.0)]
        [TestCase(double.NaN)]
        [TestCase(double.PositiveInfinity)]
        [TestCase(1e300)]
        public void SubscriptionContextReportsZeroForUnusableSessionTimeout(
            double sessionTimeout)
        {
            m_mockContext
                .Setup(c => c.SessionTimeout)
                .Returns(sessionTimeout);

            var context =
                new DefaultSubscriptionEngine.SubscriptionContextAdapter(
                    m_mockContext.Object);

            Assert.That(context.SessionTimeout, Is.EqualTo(TimeSpan.Zero));
        }

        [Test]
        public void StartPublishingDoesNotThrow()
        {
            using var engine =
                new DefaultSubscriptionEngine(m_mockContext.Object);

            Assert.That(
                () => engine.StartPublishing(timeout: 5000, fullQueue: false),
                Throws.Nothing);
        }

        [Test]
        public void PauseAndResumeDoNotThrow()
        {
            using var engine =
                new DefaultSubscriptionEngine(m_mockContext.Object);

            Assert.That(engine.PausePublishing, Throws.Nothing);
            Assert.That(engine.ResumePublishing, Throws.Nothing);
        }

        [Test]
        public async Task StopPublishingDisposesCleanlyAsync()
        {
            using var engine =
                new DefaultSubscriptionEngine(m_mockContext.Object);

            await engine.StopPublishingAsync(CancellationToken.None)
                .ConfigureAwait(false);
        }

        [Test]
        public void DisposeIsIdempotent()
        {
#pragma warning disable CA2000 // Dispose objects before losing scope
            var engine =
                new DefaultSubscriptionEngine(m_mockContext.Object);
#pragma warning restore CA2000 // Dispose objects before losing scope

            Assert.That(engine.Dispose, Throws.Nothing);
            Assert.That(engine.Dispose, Throws.Nothing);
        }

        [Test]
        public void NotifySubscriptionsChangedDoesNotThrow()
        {
            using var engine =
                new DefaultSubscriptionEngine(m_mockContext.Object);

            Assert.That(
                engine.NotifySubscriptionsChanged,
                Throws.Nothing);
        }

        [Test]
        public void GoodPublishRequestCountDefaultsToZero()
        {
            using var engine =
                new DefaultSubscriptionEngine(m_mockContext.Object);

            Assert.That(
                engine.GoodPublishRequestCount, Is.Zero);
        }

        [Test]
        public void BadPublishRequestCountDefaultsToZero()
        {
            using var engine =
                new DefaultSubscriptionEngine(m_mockContext.Object);

            Assert.That(
                engine.BadPublishRequestCount, Is.Zero);
        }

        [Test]
        public void MinMaxPublishRequestCountCanBeSet()
        {
            using var engine =
                new DefaultSubscriptionEngine(m_mockContext.Object);

            engine.MinPublishRequestCount = 3;
            engine.MaxPublishRequestCount = 20;

            Assert.That(
                engine.MinPublishRequestCount, Is.EqualTo(3));
            Assert.That(
                engine.MaxPublishRequestCount, Is.EqualTo(20));
        }

        [Test]
        public void BridgeConstructorThrowsOnNullSink()
        {
            Assert.That(
                () => new SubscriptionBridge(null!),
                Throws.TypeOf<ArgumentNullException>());
        }

        [Test]
        public void BridgeCanBeInstantiated()
        {
            var sink = new RecordingSubscriptionMessageSink();

            var bridge = new SubscriptionBridge(sink);

            Assert.That(bridge, Is.Not.Null);
        }

        [Test]
        public async Task BridgeOnKeepAliveForwardsToCacheSinkAsync()
        {
            var sink = new RecordingSubscriptionMessageSink();
            var bridge = new SubscriptionBridge(sink);
            var mockSubscription = new Mock<ISubscription>();

            await bridge.OnKeepAliveNotificationAsync(
                mockSubscription.Object,
                sequenceNumber: 1,
                publishTime: DateTime.UtcNow,
                publishStateMask: PublishState.None)
                .ConfigureAwait(false);

            Assert.That(sink.Calls, Has.Count.EqualTo(1));
            Assert.That(sink.Calls[0].Message.SequenceNumber, Is.EqualTo(1u));
        }

        [Test]
        public async Task BridgeOnDataChangeForwardsToCacheSinkAsync()
        {
            var sink = new RecordingSubscriptionMessageSink();
            var bridge = new SubscriptionBridge(sink);
            var mockSubscription = new Mock<ISubscription>();

            var changes = new DataValueChange[]
            {
                new(
                    MonitoredItem: null,
                    Value: new DataValue(new Variant(42)),
                    DiagnosticInfo: null)
            };

            await bridge.OnDataChangeNotificationAsync(
                mockSubscription.Object,
                sequenceNumber: 5,
                publishTime: DateTime.UtcNow,
                notification: changes.AsMemory(),
                publishStateMask: PublishState.None,
                stringTable: [])
                .ConfigureAwait(false);

            Assert.That(sink.Calls, Has.Count.EqualTo(1));
            Assert.That(sink.Calls[0].Message.SequenceNumber, Is.EqualTo(5u));
        }

        [Test]
        public async Task BridgeOnEventNotificationForwardsToCacheSinkAsync()
        {
            var sink = new RecordingSubscriptionMessageSink();
            var bridge = new SubscriptionBridge(sink);
            var mockSubscription = new Mock<ISubscription>();

            var events = new EventNotification[]
            {
                new(
                    MonitoredItem: null,
                    Fields: new ArrayOf<Variant>(
                        new[] { new Variant("event-data") }))
            };

            await bridge.OnEventDataNotificationAsync(
                mockSubscription.Object,
                sequenceNumber: 10,
                publishTime: DateTime.UtcNow,
                notification: events.AsMemory(),
                publishStateMask: PublishState.None,
                stringTable: ["ns-entry"])
                .ConfigureAwait(false);

            Assert.That(sink.Calls, Has.Count.EqualTo(1));
            Assert.That(sink.Calls[0].Message.SequenceNumber, Is.EqualTo(10u));
        }

        [Test]
        public async Task BridgeDataChangeWithDiagnosticsPreservesDiagnosticInfoAsync()
        {
            var sink = new RecordingSubscriptionMessageSink();
            var bridge = new SubscriptionBridge(sink);
            var mockSubscription = new Mock<ISubscription>();

            var diag = new DiagnosticInfo
            {
                AdditionalInfo = "test-diag"
            };
            var changes = new DataValueChange[]
            {
                new(
                    MonitoredItem: null,
                    Value: new DataValue(new Variant(1)),
                    DiagnosticInfo: diag)
            };

            await bridge.OnDataChangeNotificationAsync(
                mockSubscription.Object,
                sequenceNumber: 7,
                publishTime: DateTime.UtcNow,
                notification: changes.AsMemory(),
                publishStateMask: PublishState.None,
                stringTable: [])
                .ConfigureAwait(false);

            Assert.That(sink.Calls, Has.Count.EqualTo(1));
            NotificationMessage captured = sink.Calls[0].Message;
            Assert.That(
                captured.NotificationData.Count, Is.EqualTo(1));
            ExtensionObject ext = captured.NotificationData[0];
            Assert.That(
                ext.TryGetValue(
                    out DataChangeNotification? dcn),
                Is.True);
            Assert.That(
                dcn!.DiagnosticInfos.Count, Is.EqualTo(1));
            Assert.That(
                dcn.DiagnosticInfos[0].AdditionalInfo,
                Is.EqualTo("test-diag"));
        }

        /// <summary>
        /// Hand-rolled fake for <see cref="ISubscriptionMessageSink"/>
        /// (internal interface) that records every <c>SaveMessageInCache</c>
        /// call. Replaces a Moq-driven mock so that the test assembly does
        /// not need <c>InternalsVisibleTo("DynamicProxyGenAssembly2")</c>
        /// on the production assembly.
        /// </summary>
        private sealed class RecordingSubscriptionMessageSink
            : ISubscriptionMessageSink
        {
            public List<(ArrayOf<uint> AvailableSequenceNumbers, NotificationMessage Message)> Calls { get; } = [];

            public void SaveMessageInCache(
                ArrayOf<uint> availableSequenceNumbers,
                NotificationMessage message)
            {
                Calls.Add((availableSequenceNumbers, message));
            }
        }
    }
}