using Moq;
using Opc.Ua;
using Opc.Ua.Client;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;

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

/// <summary>
///     Review 2026-10-21 R06:O-8 — <c>AcknowledgeAsync</c> swallowed every non-cancellation transport failure, so
///     the host logged the Part 9 ack as applied while upstream still showed the condition unacknowledged. A
///     transport failure (no reply) now propagates with its status; a reply — even one carrying per-ack refusals —
///     still returns normally (that is the server answering, logged per ack).
/// </summary>
[Trait("Category", "Unit")]
public sealed class OpcUaClientAcknowledgeFailureTests
{
    private const string Condition = "ns=2;s=Pump17";

    private static Mock<ISession> NewSession()
    {
        var mock = new Mock<ISession>(MockBehavior.Loose);
        mock.SetupGet(s => s.MessageContext).Returns(new ServiceMessageContext(SdkTelemetry.Context));
        mock.SetupGet(s => s.NamespaceUris).Returns(new NamespaceTable());
        return mock;
    }

    private static AlarmAcknowledgeRequest[] Ack() => [new(Condition, Condition, "operator ack")];

    /// <summary>A transport failure on the Acknowledge call reaches the caller with the transport status.</summary>
    [Fact]
    public async Task A_transport_failure_propagates_with_its_status()
    {
        using var drv = new OpcUaClientDriver(new OpcUaClientDriverOptions(), "opcua-o8");
        var session = NewSession();
        session.Setup(s => s.CallAsync(It.IsAny<RequestHeader>(), It.IsAny<CallMethodRequestCollection>(), It.IsAny<CancellationToken>()))
            .ThrowsAsync(new ServiceResultException(StatusCodes.BadConnectionClosed));
        drv.SetSessionForTest(session.Object);

        var ex = await Should.ThrowAsync<ServiceResultException>(() =>
            drv.AcknowledgeAsync(Ack(), TestContext.Current.CancellationToken));

        ex.StatusCode.ShouldBe(StatusCodes.BadConnectionClosed);
    }

    /// <summary>Positive control: a reply returns normally and the call reached the wire.</summary>
    [Fact]
    public async Task Positive_control_a_reply_returns_normally()
    {
        using var drv = new OpcUaClientDriver(new OpcUaClientDriverOptions(), "opcua-o8-ok");
        var session = NewSession();
        session.Setup(s => s.CallAsync(It.IsAny<RequestHeader>(), It.IsAny<CallMethodRequestCollection>(), It.IsAny<CancellationToken>()))
            .ReturnsAsync(new CallResponse
            {
                ResponseHeader = new ResponseHeader(),
                Results = [new CallMethodResult { StatusCode = StatusCodes.BadConditionBranchAlreadyAcked }],
                DiagnosticInfos = [],
            });
        drv.SetSessionForTest(session.Object);

        await drv.AcknowledgeAsync(Ack(), TestContext.Current.CancellationToken);

        session.Verify(s => s.CallAsync(It.IsAny<RequestHeader>(), It.IsAny<CallMethodRequestCollection>(), It.IsAny<CancellationToken>()),
            Times.Once);
    }

    /// <summary>A session lost while the ack queued on the gate fails the ack rather than reporting it applied.</summary>
    [Fact]
    public async Task A_session_lost_while_queued_fails_the_ack()
    {
        var ct = TestContext.Current.CancellationToken;
        using var drv = new OpcUaClientDriver(new OpcUaClientDriverOptions(), "opcua-o8-lost");
        drv.SetSessionForTest(NewSession().Object);

        await drv.Gate.WaitAsync(ct);
        var call = drv.AcknowledgeAsync(Ack(), ct);
        drv.SetSessionForTest(null);
        drv.Gate.Release();

        await Should.ThrowAsync<ServiceResultException>(() => call);
    }
}