scadalink-design/tests/ScadaLink.DataConnectionLayer.Tests/DataConnectionActorTests.cs

using Akka.Actor;
using Akka.TestKit.Xunit2;
using NSubstitute;
using ScadaLink.Commons.Interfaces.Protocol;
using ScadaLink.Commons.Messages.DataConnection;
using ScadaLink.Commons.Types.Enums;
using ScadaLink.DataConnectionLayer.Actors;

namespace ScadaLink.DataConnectionLayer.Tests;

/// <summary>
/// WP-6: Tests for DataConnectionActor Become/Stash state machine.
/// WP-9: Auto-reconnect and bad quality tests.
/// WP-10: Transparent re-subscribe tests.
/// WP-11: Write-back support tests.
/// WP-12: Tag path resolution with retry tests.
/// WP-13: Health reporting tests.
/// WP-14: Subscription lifecycle tests.
/// </summary>
public class DataConnectionActorTests : TestKit
{
    private readonly IDataConnection _mockAdapter;
    private readonly DataConnectionOptions _options;

    public DataConnectionActorTests()
        : base(@"akka.loglevel = DEBUG")
    {
        _mockAdapter = Substitute.For<IDataConnection>();
        _options = new DataConnectionOptions
        {
            ReconnectInterval = TimeSpan.FromMilliseconds(100),
            TagResolutionRetryInterval = TimeSpan.FromMilliseconds(200),
            WriteTimeout = TimeSpan.FromSeconds(5)
        };
    }

    private IActorRef CreateConnectionActor(string name = "test-conn")
    {
        return Sys.ActorOf(Props.Create(() =>
            new DataConnectionActor(name, _mockAdapter, _options)), name);
    }

    [Fact]
    public void WP6_StartsInConnectingState_AttemptsConnect()
    {
        _mockAdapter.ConnectAsync(Arg.Any<IDictionary<string, string>>(), Arg.Any<CancellationToken>())
            .Returns(Task.CompletedTask);

        var actor = CreateConnectionActor();

        // Give it time to attempt connection
        AwaitCondition(() =>
            _mockAdapter.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "ConnectAsync"),
            TimeSpan.FromSeconds(2));
    }

    [Fact]
    public void WP6_ConnectingState_StashesSubscribeRequests()
    {
        // Make connect hang so we stay in Connecting
        var tcs = new TaskCompletionSource();
        _mockAdapter.ConnectAsync(Arg.Any<IDictionary<string, string>>(), Arg.Any<CancellationToken>())
            .Returns(tcs.Task);

        var actor = CreateConnectionActor("stash-test");

        // Send subscribe while connecting — should be stashed
        actor.Tell(new SubscribeTagsRequest(
            "corr1", "inst1", "stash-test", ["tag1"], DateTimeOffset.UtcNow));

        // No response yet (stashed)
        ExpectNoMsg(TimeSpan.FromMilliseconds(200));

        // Complete connection — should unstash and process
        _mockAdapter.SubscribeAsync(Arg.Any<string>(), Arg.Any<SubscriptionCallback>(), Arg.Any<CancellationToken>())
            .Returns("sub-001");

        tcs.SetResult();

        // Now we should get the response
        ExpectMsg<SubscribeTagsResponse>(TimeSpan.FromSeconds(2));
    }

    [Fact]
    public async Task WP11_ConnectedState_Write_ReturnsResult()
    {
        _mockAdapter.ConnectAsync(Arg.Any<IDictionary<string, string>>(), Arg.Any<CancellationToken>())
            .Returns(Task.CompletedTask);
        _mockAdapter.WriteAsync("tag1", 42, Arg.Any<CancellationToken>())
            .Returns(new WriteResult(true, null));

        var actor = CreateConnectionActor("write-test");

        // Wait for connected state
        AwaitCondition(() =>
            _mockAdapter.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "ConnectAsync"),
            TimeSpan.FromSeconds(2));

        // Small delay for state transition
        await Task.Delay(200);

        actor.Tell(new WriteTagRequest("corr1", "write-test", "tag1", 42, DateTimeOffset.UtcNow));

        var response = ExpectMsg<WriteTagResponse>(TimeSpan.FromSeconds(3));
        Assert.True(response.Success);
    }

    [Fact]
    public async Task WP11_Write_Failure_ReturnedSynchronously()
    {
        _mockAdapter.ConnectAsync(Arg.Any<IDictionary<string, string>>(), Arg.Any<CancellationToken>())
            .Returns(Task.CompletedTask);
        _mockAdapter.WriteAsync("tag1", 42, Arg.Any<CancellationToken>())
            .Returns(new WriteResult(false, "Device offline"));

        var actor = CreateConnectionActor("write-fail-test");

        await Task.Delay(300);

        actor.Tell(new WriteTagRequest("corr1", "write-fail-test", "tag1", 42, DateTimeOffset.UtcNow));

        var response = ExpectMsg<WriteTagResponse>(TimeSpan.FromSeconds(3));
        Assert.False(response.Success);
        Assert.Equal("Device offline", response.ErrorMessage);
    }

    [Fact]
    public async Task WP13_HealthReport_ReturnsConnectionStatus()
    {
        _mockAdapter.ConnectAsync(Arg.Any<IDictionary<string, string>>(), Arg.Any<CancellationToken>())
            .Returns(Task.CompletedTask);
        _mockAdapter.Status.Returns(ConnectionHealth.Connected);

        var actor = CreateConnectionActor("health-test");

        await Task.Delay(300);

        actor.Tell(new DataConnectionActor.GetHealthReport());

        var report = ExpectMsg<DataConnectionHealthReport>(TimeSpan.FromSeconds(2));
        Assert.Equal("health-test", report.ConnectionName);
        Assert.Equal(ConnectionHealth.Connected, report.Status);
    }
}