using Akka.Actor;
using Akka.TestKit.Xunit2;
using NSubstitute;
using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Protocol;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.DataConnection;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums;
using ZB.MOM.WW.ScadaBridge.DataConnectionLayer.Actors;
using ZB.MOM.WW.ScadaBridge.HealthMonitoring;

namespace ZB.MOM.WW.ScadaBridge.DataConnectionLayer.Tests.Actors;

/// <summary>
/// Review 2026-10-21 (lane A M2): a data connection name becomes its DataConnectionActor's
/// name. The old sanitiser kept non-ASCII letters and '$' (both refused by Akka) and mapped
/// "PLC A" and "PLC-A" to the same name; either made <c>Context.ActorOf</c> throw on the
/// manager's own thread, restarting it and dropping every live connection.
/// </summary>
[Collection("DataConnectionManagerActor")]
public class ConnectionActorNameTests : TestKit
{
    private readonly IDataConnectionFactory _factory = Substitute.For<IDataConnectionFactory>();
    private readonly ISiteHealthCollector _health = Substitute.For<ISiteHealthCollector>();
    private volatile bool _slowDispose;
    private readonly DataConnectionOptions _options = new()
    {
        ReconnectInterval = TimeSpan.FromMilliseconds(100),
        TagResolutionRetryInterval = TimeSpan.FromMilliseconds(200)
    };

    /// <summary>Creates the test kit with a factory that hands out connected mock adapters.</summary>
    public ConnectionActorNameTests()
    {
        _factory.Create(Arg.Any<string>(), Arg.Any<IDictionary<string, string>>()).Returns(_ =>
        {
            var adapter = Substitute.For<IDataConnection>();
            adapter.ConnectAsync(Arg.Any<IDictionary<string, string>>(), Arg.Any<CancellationToken>())
                .Returns(Task.CompletedTask);
            adapter.Status.Returns(ConnectionHealth.Connected);
            adapter.SubscribeAsync(Arg.Any<string>(), Arg.Any<SubscriptionCallback>(), Arg.Any<CancellationToken>())
                .Returns("sub-1");
            // A synchronous delay inside DisposeAsync holds the stopping child in PostStop, which
            // keeps its actor name reserved — the dispose window the L2 tests exercise.
            adapter.DisposeAsync().Returns(_ =>
            {
                if (_slowDispose) Thread.Sleep(400);
                return ValueTask.CompletedTask;
            });
            return adapter;
        });
    }

    /// <summary>Every sanitised name is a legal Akka path element, including non-ASCII and '$' input.</summary>
    [Theory]
    [InlineData("PLC A")]
    [InlineData("Ofen Süd")]
    [InlineData("$PLC")]
    [InlineData("名前")]
    [InlineData("a/b#c[d]%e")]
    [InlineData("")]
    public void Sanitize_AlwaysYieldsAValidActorName(string connectionName)
    {
        Assert.True(ActorPath.IsValidPathElement(ConnectionActorNames.Sanitize(connectionName)));
    }

    private IActorRef CreateManager() => Sys.ActorOf(Props.Create(() =>
        new DataConnectionManagerActor(_factory, _options, _health)));

    private SubscribeTagsResponse Subscribe(IActorRef manager, string connection)
    {
        manager.Tell(new SubscribeTagsRequest(
            Guid.NewGuid().ToString("N"), "inst1", connection, ["tag1"], DateTimeOffset.UtcNow));
        return ExpectMsg<SubscribeTagsResponse>(TimeSpan.FromSeconds(10));
    }

    /// <summary>A non-ASCII connection name is created instead of crashing the manager.</summary>
    [Fact]
    public void NonAsciiConnectionName_IsCreated()
    {
        var manager = CreateManager();
        manager.Tell(new CreateConnectionCommand("Ofen Süd", "OpcUa", new Dictionary<string, string>(), null, 3));

        var response = Subscribe(manager, "Ofen Süd");
        Assert.DoesNotContain("Unknown connection", response.ErrorMessage ?? "");
    }

    /// <summary>
    /// Two names that sanitise alike: the second fails alone; the first — and the manager —
    /// keep working.
    /// </summary>
    [Fact]
    public void CollidingSanitisedNames_FailOnlyTheLaterConnection()
    {
        var manager = CreateManager();
        manager.Tell(new CreateConnectionCommand("PLC A", "OpcUa", new Dictionary<string, string>(), null, 3));
        manager.Tell(new CreateConnectionCommand("PLC-A", "OpcUa", new Dictionary<string, string>(), null, 3));

        Assert.Contains("Unknown connection", Subscribe(manager, "PLC-A").ErrorMessage);
        Assert.DoesNotContain("Unknown connection", Subscribe(manager, "PLC A").ErrorMessage ?? "");
    }

    /// <summary>
    /// Follow-up L2: a Remove immediately followed by a Create of the SAME name (a redeploy that
    /// rebuilds the connection) lands while the stopped child is still terminating, so its actor
    /// name is still reserved. The create used to be refused permanently as a "collision" — and
    /// the deployment manager, having recorded the config hash, never resent it. The manager now
    /// queues the create until the old child's Terminated arrives.
    /// </summary>
    [Fact]
    public void RemoveThenCreateSameName_InsideDisposeWindow_IsCreatedOnceTheOldChildTerminates()
    {
        _slowDispose = true;
        var manager = CreateManager();
        manager.Tell(new CreateConnectionCommand("PLC1", "OpcUa", new Dictionary<string, string>(), null, 3));
        manager.Tell(new RemoveConnectionCommand("PLC1"));
        manager.Tell(new CreateConnectionCommand("PLC1", "OpcUa", new Dictionary<string, string>(), null, 3));

        AwaitAssert(
            () => Assert.DoesNotContain("Unknown connection", Subscribe(manager, "PLC1").ErrorMessage ?? ""),
            TimeSpan.FromSeconds(10),
            TimeSpan.FromMilliseconds(100));
    }

    /// <summary>
    /// Follow-up L2: a Remove that arrives while a create is still queued behind a terminating
    /// child cancels the queued create — the connection stays removed.
    /// </summary>
    [Fact]
    public void RemoveWhileCreateQueued_CancelsTheQueuedCreate()
    {
        _slowDispose = true;
        var manager = CreateManager();
        manager.Tell(new CreateConnectionCommand("PLC2", "OpcUa", new Dictionary<string, string>(), null, 3));
        manager.Tell(new RemoveConnectionCommand("PLC2"));
        manager.Tell(new CreateConnectionCommand("PLC2", "OpcUa", new Dictionary<string, string>(), null, 3));
        manager.Tell(new RemoveConnectionCommand("PLC2"));

        // Let the old child terminate (and any wrongly-queued create run) before asserting.
        Thread.Sleep(1000);
        Assert.Contains("Unknown connection", Subscribe(manager, "PLC2").ErrorMessage);
    }
}