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using NUnit.Framework;
using Opc.Ua.Redundancy.Server;
using Opc.Ua.Tests;

namespace Opc.Ua.Server.Tests.Redundancy
{
    /// <summary>
    /// Unit tests for <see cref="NodeStateSerializer"/>.
    /// </summary>
    [TestFixture]
    [Category("Distributed")]
    [Parallelizable(ParallelScope.All)]
    public class NodeStateSerializerTests
    {
        private const ushort NamespaceIndex = 1;
        private SystemContext m_context = null!;

        [OneTimeSetUp]
        public void OneTimeSetUp()
        {
            ITelemetryContext telemetry = NUnitTelemetryContext.Create();
            var messageContext = ServiceMessageContext.CreateEmpty(telemetry);
            messageContext.NamespaceUris.GetIndexOrAppend("urn:test:serializer");
            m_context = new SystemContext(telemetry)
            {
                NamespaceUris = messageContext.NamespaceUris,
                ServerUris = messageContext.ServerUris,
                EncodeableFactory = messageContext.Factory
            };
        }

        [Test]
        public void ObjectRoundTripsAsBaseObjectState()
        {
            var original = new BaseObjectState(null)
            {
                NodeId = new NodeId("obj", NamespaceIndex),
                BrowseName = new QualifiedName("Obj", NamespaceIndex),
                DisplayName = new LocalizedText("Obj")
            };

            ByteString payload = NodeStateSerializer.Serialize(m_context, original);
            NodeState restored = NodeStateSerializer.Deserialize(m_context, payload);

            Assert.That(restored, Is.InstanceOf<BaseObjectState>());
            Assert.That(restored.NodeClass, Is.EqualTo(NodeClass.Object));
            Assert.That(restored.BrowseName, Is.EqualTo(original.BrowseName));
        }

        [Test]
        public void VariableRoundTripsWithValue()
        {
            var original = new BaseDataVariableState(null)
            {
                NodeId = new NodeId("var", NamespaceIndex),
                BrowseName = new QualifiedName("Var", NamespaceIndex),
                DisplayName = new LocalizedText("Var"),
                DataType = DataTypeIds.Double,
                ValueRank = ValueRanks.Scalar,
                Value = new Variant(2.5)
            };

            ByteString payload = NodeStateSerializer.Serialize(m_context, original);
            NodeState restored = NodeStateSerializer.Deserialize(m_context, payload);

            Assert.That(restored, Is.InstanceOf<BaseDataVariableState>());
            Assert.That(restored.NodeClass, Is.EqualTo(NodeClass.Variable));
            var variable = (BaseDataVariableState)restored;
            Assert.That(variable.Value, Is.EqualTo(new Variant(2.5)));
            Assert.That(variable.DataType, Is.EqualTo(DataTypeIds.Double));
        }

        [Test]
        public void MethodRoundTripsAsMethodState()
        {
            var original = new MethodState(null)
            {
                NodeId = new NodeId("m", NamespaceIndex),
                BrowseName = new QualifiedName("DoIt", NamespaceIndex),
                DisplayName = new LocalizedText("DoIt"),
                Executable = true,
                UserExecutable = true
            };

            ByteString payload = NodeStateSerializer.Serialize(m_context, original);
            NodeState restored = NodeStateSerializer.Deserialize(m_context, payload);

            Assert.That(restored, Is.InstanceOf<MethodState>());
            Assert.That(((MethodState)restored).Executable, Is.True);
        }

        [Test]
        public void DeserializeTooShortPayloadThrows()
        {
            var tooShort = ByteString.From(new byte[] { 1, 2 });

            Assert.That(
                () => NodeStateSerializer.Deserialize(m_context, tooShort),
                Throws.TypeOf<ServiceResultException>());
        }

        [Test]
        public void SerializeThrowsOnNullContext()
        {
            var node = new BaseObjectState(null);

            Assert.That(
                () => NodeStateSerializer.Serialize(null!, node),
                Throws.ArgumentNullException);
        }

        [Test]
        public void SerializeThrowsOnNullNode()
        {
            Assert.That(
                () => NodeStateSerializer.Serialize(m_context, null!),
                Throws.ArgumentNullException);
        }

        [Test]
        public void DeserializeThrowsOnNullContext()
        {
            var node = new BaseObjectState(null)
            {
                NodeId = new NodeId("obj", NamespaceIndex),
                BrowseName = new QualifiedName("Obj", NamespaceIndex)
            };
            ByteString payload = NodeStateSerializer.Serialize(m_context, node);

            Assert.That(
                () => NodeStateSerializer.Deserialize(null!, payload),
                Throws.ArgumentNullException);
        }

        [Test]
        public void ViewRoundTripsAsViewState()
        {
            var original = new ViewState
            {
                NodeId = new NodeId("view", NamespaceIndex),
                BrowseName = new QualifiedName("View", NamespaceIndex),
                DisplayName = new LocalizedText("View"),
                ContainsNoLoops = true
            };

            NodeState restored = RoundTrip(original);

            Assert.That(restored, Is.InstanceOf<ViewState>());
            Assert.That(restored.NodeClass, Is.EqualTo(NodeClass.View));
            Assert.That(((ViewState)restored).ContainsNoLoops, Is.True);
        }

        [Test]
        public void ObjectTypeRoundTripsAsBaseObjectTypeState()
        {
            var original = new BaseObjectTypeState
            {
                NodeId = new NodeId("otype", NamespaceIndex),
                BrowseName = new QualifiedName("OType", NamespaceIndex),
                DisplayName = new LocalizedText("OType"),
                IsAbstract = true
            };

            NodeState restored = RoundTrip(original);

            Assert.That(restored, Is.InstanceOf<BaseObjectTypeState>());
            Assert.That(restored.NodeClass, Is.EqualTo(NodeClass.ObjectType));
            Assert.That(((BaseObjectTypeState)restored).IsAbstract, Is.True);
        }

        [Test]
        public void VariableTypeRoundTripsAsBaseDataVariableTypeState()
        {
            var original = new BaseDataVariableTypeState
            {
                NodeId = new NodeId("vtype", NamespaceIndex),
                BrowseName = new QualifiedName("VType", NamespaceIndex),
                DisplayName = new LocalizedText("VType"),
                DataType = DataTypeIds.Int32,
                ValueRank = ValueRanks.Scalar
            };

            NodeState restored = RoundTrip(original);

            Assert.That(restored, Is.InstanceOf<BaseDataVariableTypeState>());
            Assert.That(restored.NodeClass, Is.EqualTo(NodeClass.VariableType));
            Assert.That(((BaseDataVariableTypeState)restored).DataType, Is.EqualTo(DataTypeIds.Int32));
        }

        [Test]
        public void ReferenceTypeRoundTripsAsReferenceTypeState()
        {
            var original = new ReferenceTypeState
            {
                NodeId = new NodeId("rtype", NamespaceIndex),
                BrowseName = new QualifiedName("RType", NamespaceIndex),
                DisplayName = new LocalizedText("RType"),
                InverseName = new LocalizedText("RTypeInverse"),
                Symmetric = false
            };

            NodeState restored = RoundTrip(original);

            Assert.That(restored, Is.InstanceOf<ReferenceTypeState>());
            Assert.That(restored.NodeClass, Is.EqualTo(NodeClass.ReferenceType));
            Assert.That(((ReferenceTypeState)restored).InverseName, Is.EqualTo(original.InverseName));
        }

        [Test]
        public void DataTypeRoundTripsAsDataTypeState()
        {
            var original = new DataTypeState
            {
                NodeId = new NodeId("dtype", NamespaceIndex),
                BrowseName = new QualifiedName("DType", NamespaceIndex),
                DisplayName = new LocalizedText("DType"),
                IsAbstract = true
            };

            NodeState restored = RoundTrip(original);

            Assert.That(restored, Is.InstanceOf<DataTypeState>());
            Assert.That(restored.NodeClass, Is.EqualTo(NodeClass.DataType));
            Assert.That(((DataTypeState)restored).IsAbstract, Is.True);
        }

        [Test]
        public void DeserializeUnknownNodeClassThrows()
        {
            // A framed payload whose header is a NodeClass value the reconstructor does not support.
            var payload = ByteString.From(new byte[] { 3, 0, 0, 0 });

            Assert.That(
                () => NodeStateSerializer.Deserialize(m_context, payload),
                Throws.TypeOf<ServiceResultException>());
        }

        private NodeState RoundTrip(NodeState original)
        {
            ByteString payload = NodeStateSerializer.Serialize(m_context, original);
            return NodeStateSerializer.Deserialize(m_context, payload);
        }
    }
}