using Akka.Actor;
using Akka.Event;
using Microsoft.EntityFrameworkCore;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
using ZB.MOM.WW.OtOpcUa.Commons.Types;
using ZB.MOM.WW.OtOpcUa.Configuration;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.Runtime.Drivers;
using ZB.MOM.WW.OtOpcUa.Runtime.Tests.Harness;

namespace ZB.MOM.WW.OtOpcUa.Runtime.Tests.Drivers;

/// <summary>
///     Review 02 H5: the <c>Stale</c> behaviour registered no receive for a driver child's value/alarm bursts (nor
///     for a late <c>ArtifactForApply</c> / <c>ApplyWedged</c> pipe-back), so any that landed there hit
///     <c>Unhandled</c> — dead-letter noise and a dropped message with no log naming why. They are now explicit
///     drops. The two private pipe-back records cannot be constructed from a test; the two public child
///     messages are pinned here, and the private pair by the same registration pattern (compile-time).
/// </summary>
public sealed class DriverHostActorStaleDropTests : RuntimeActorTestBase
{
    private static readonly NodeId TestNode = NodeId.Parse("stale-drop-test");

    [Fact]
    public void Child_value_and_alarm_bursts_landing_in_Stale_are_dropped_not_unhandled()
    {
        var unhandled = CreateTestProbe();
        Sys.EventStream.Subscribe(unhandled.Ref, typeof(UnhandledMessage));

        // ThrowingDbFactory ⇒ Bootstrap's catch ⇒ Become(Stale).
        var host = Sys.ActorOf(DriverHostActor.Props(
            new ThrowingDbFactory(), TestNode, CreateTestProbe().Ref,
            localRoles: new HashSet<string> { "driver" }));
        // Barrier: Stale answers RouteNodeWrite synchronously, so a reply proves the host is in Stale.
        var asker = CreateTestProbe();
        host.Tell(new DriverHostActor.RouteNodeWrite("eq-x/speed", 0.0, AddressSpaceRealm.Uns), asker.Ref);
        asker.ExpectMsg<DriverHostActor.NodeWriteResult>(PresenceBudget).Reason!.ShouldContain("stale");

        // Positive control: an unknown message IS reported as unhandled by this host.
        host.Tell("not a message the host knows");
        unhandled.ExpectMsg<UnhandledMessage>(m => ReferenceEquals(m.Recipient, host) || m.Recipient.Equals(host), PresenceBudget);

        host.Tell(new DriverInstanceActor.AttributeValueBatchPublished(
            "DI-1", new[] { new DriverInstanceActor.AttributeValueItem("Plant/x/y", 1.0, OpcUaStatus.Good, DateTime.UtcNow) }));
        host.Tell(new DriverInstanceActor.AttributeAlarmPublished(
            "DI-1", new AlarmEventArgs(new Handle(), "Plant/x/alarm", "Plant/x/alarm", "AlarmCondition", "test",
                AlarmSeverity.High, DateTime.UtcNow)));
        // Barrier again, then the absence window.
        host.Tell(new DriverHostActor.RouteNodeWrite("eq-x/speed", 0.0, AddressSpaceRealm.Uns), asker.Ref);
        asker.ExpectMsg<DriverHostActor.NodeWriteResult>(PresenceBudget);

        unhandled.ExpectNoMsg(TimeSpan.FromMilliseconds(500));
    }

    private sealed class Handle : IAlarmSubscriptionHandle
    {
        public string DiagnosticId => "stale-test";
    }

    private sealed class ThrowingDbFactory : IDbContextFactory<OtOpcUaConfigDbContext>
    {
        public OtOpcUaConfigDbContext CreateDbContext() => throw new InvalidOperationException("db unreachable");
    }
}