using Moq;
using Opc.Ua;
using Opc.Ua.Client;
using Shouldly;
using Xunit;

namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.Tests;

/// <summary>
///     Review 2026-10-21 R06:O-5 — the live picker's side-panel <c>AttributesAsync</c> was a stub returning nothing,
///     so the operator saw no DataType / array / access information for an upstream variable. It now reads the
///     variable's attributes and maps them through the same <see cref="UpstreamAttributeMapping"/> the runtime
///     driver's discovery uses.
/// </summary>
[Trait("Category", "Unit")]
public sealed class OpcUaClientBrowseSessionAttributesTests
{
    private const string Speed = "ns=0;s=Speed";

    private static Mock<ISession> SessionReturning(NodeClass nodeClass, NodeId dataType, int valueRank, byte userAccess)
    {
        var mock = new Mock<ISession>(MockBehavior.Loose);
        mock.SetupGet(s => s.MessageContext).Returns(new ServiceMessageContext());
        mock.SetupGet(s => s.NamespaceUris).Returns(new NamespaceTable());
        mock.Setup(s => s.ReadAsync(
                It.IsAny<RequestHeader>(), It.IsAny<double>(), It.IsAny<TimestampsToReturn>(),
                It.IsAny<ReadValueIdCollection>(), It.IsAny<CancellationToken>()))
            .ReturnsAsync((RequestHeader _, double _, TimestampsToReturn _, ReadValueIdCollection nodes, CancellationToken _) =>
                new ReadResponse
                {
                    ResponseHeader = new ResponseHeader(),
                    Results = [.. nodes.Select(n => n.AttributeId switch
                    {
                        Attributes.NodeClass => new DataValue(new Variant((int)nodeClass)),
                        Attributes.DisplayName => new DataValue(new Variant(new LocalizedText("Speed"))),
                        Attributes.DataType => new DataValue(new Variant(dataType)),
                        Attributes.ValueRank => new DataValue(new Variant(valueRank)),
                        Attributes.UserAccessLevel => new DataValue(new Variant(userAccess)),
                        _ => new DataValue(StatusCodes.BadAttributeIdInvalid),
                    })],
                    DiagnosticInfos = [],
                });
        return mock;
    }

    private static OpcUaClientBrowseSession NewSession(Mock<ISession> mock)
        => new(mock.Object, NamespaceMap.FromTable(new NamespaceTable()), ObjectIds.ObjectsFolder);

    /// <summary>A writable Double array variable reports Float64 / array / Operate.</summary>
    [Fact]
    public async Task A_variable_reports_its_mapped_data_type_array_shape_and_access()
    {
        var mock = SessionReturning(NodeClass.Variable, DataTypeIds.Double, valueRank: 1, userAccess: 0x03);
        await using var session = NewSession(mock);

        var attrs = await session.AttributesAsync(Speed, TestContext.Current.CancellationToken);

        var a = attrs.ShouldHaveSingleItem();
        a.Name.ShouldBe("Speed");
        a.DriverDataType.ShouldBe("Float64");
        a.IsArray.ShouldBeTrue();
        a.SecurityClass.ShouldBe("Operate");
        a.IsAlarm.ShouldBeFalse();
    }

    /// <summary>A read-only scalar Int32 variable reports Int32 / scalar / ViewOnly.</summary>
    [Fact]
    public async Task A_read_only_scalar_reports_view_only()
    {
        var mock = SessionReturning(NodeClass.Variable, DataTypeIds.Int32, valueRank: -1, userAccess: 0x01);
        await using var session = NewSession(mock);

        var a = (await session.AttributesAsync(Speed, TestContext.Current.CancellationToken)).ShouldHaveSingleItem();

        a.DriverDataType.ShouldBe("Int32");
        a.IsArray.ShouldBeFalse();
        a.SecurityClass.ShouldBe("ViewOnly");
    }

    /// <summary>
    ///     An Object (folder) has no value attributes to show. The positive control is the variable case above,
    ///     through the same mock and read.
    /// </summary>
    [Fact]
    public async Task An_object_node_has_no_attributes()
    {
        var mock = SessionReturning(NodeClass.Object, DataTypeIds.Int32, valueRank: -1, userAccess: 0x01);
        await using var session = NewSession(mock);

        (await session.AttributesAsync(Speed, TestContext.Current.CancellationToken)).ShouldBeEmpty();
    }

    /// <summary>An unresolvable node id is refused like <c>ExpandAsync</c> does.</summary>
    [Fact]
    public async Task An_unresolvable_node_id_throws()
    {
        var mock = SessionReturning(NodeClass.Variable, DataTypeIds.Int32, -1, 1);
        await using var session = NewSession(mock);

        await Should.ThrowAsync<ArgumentException>(() =>
            session.AttributesAsync("nsu=urn:not-in-table;s=X", TestContext.Current.CancellationToken));
    }

    private sealed class TrackingCredential : IDisposable
    {
        public int Disposed { get; private set; }

        public void Dispose() => Disposed++;
    }

    /// <summary>Review m9: the browse session disposes the user certificate it was handed, with itself.</summary>
    [Fact]
    public async Task The_session_disposes_the_credential_it_owns()
    {
        var mock = SessionReturning(NodeClass.Variable, DataTypeIds.Int32, -1, 1);
        var credential = new TrackingCredential();
        var session = new OpcUaClientBrowseSession(
            mock.Object, NamespaceMap.FromTable(new NamespaceTable()), ObjectIds.ObjectsFolder, credential);

        credential.Disposed.ShouldBe(0, "positive control: still owned while the session is open");
        await session.DisposeAsync();
        await session.DisposeAsync();

        credential.Disposed.ShouldBe(1);
    }
}