using Akka.Actor;
using Akka.TestKit.Xunit2;
using ScadaLink.Commons.Messages.Communication;
using ScadaLink.Commons.Messages.Deployment;
using ScadaLink.Commons.Messages.DebugView;
using ScadaLink.Commons.Messages.Health;
using ScadaLink.Communication.Actors;

namespace ScadaLink.Communication.Tests;

/// <summary>
/// WP-4: Tests for CentralCommunicationActor message routing.
/// WP-5: Tests for connection failure and failover handling.
/// </summary>
public class CentralCommunicationActorTests : TestKit
{
    public CentralCommunicationActorTests()
        : base(@"akka.loglevel = DEBUG")
    {
    }

    [Fact]
    public void RegisterSite_AllowsMessageRouting()
    {
        var centralActor = Sys.ActorOf(Props.Create(() => new CentralCommunicationActor()));

        // Register a site pointing to the test probe
        var probe = CreateTestProbe();
        centralActor.Tell(new RegisterSite("site1", probe.Ref.Path.ToString()));

        // Send a message to the site
        var command = new DeployInstanceCommand(
            "dep1", "inst1", "hash1", "{}", "admin", DateTimeOffset.UtcNow);
        centralActor.Tell(new SiteEnvelope("site1", command));

        // The probe should receive the inner message (not the envelope)
        probe.ExpectMsg<DeployInstanceCommand>(msg => msg.DeploymentId == "dep1");
    }

    [Fact]
    public void UnregisteredSite_MessageIsDropped()
    {
        var centralActor = Sys.ActorOf(Props.Create(() => new CentralCommunicationActor()));

        var command = new DeployInstanceCommand(
            "dep1", "inst1", "hash1", "{}", "admin", DateTimeOffset.UtcNow);
        centralActor.Tell(new SiteEnvelope("unknown-site", command));

        // No crash, no response — the ask will timeout on the caller side
        ExpectNoMsg(TimeSpan.FromMilliseconds(200));
    }

    [Fact]
    public void ConnectionLost_DebugStreamsKilled()
    {
        var centralActor = Sys.ActorOf(Props.Create(() => new CentralCommunicationActor()));
        var siteProbe = CreateTestProbe();

        // Register site
        centralActor.Tell(new RegisterSite("site1", siteProbe.Ref.Path.ToString()));

        // Subscribe to debug view (this tracks the subscription)
        var subscriberProbe = CreateTestProbe();
        var subRequest = new SubscribeDebugViewRequest("inst1", "corr-123");
        centralActor.Tell(new SiteEnvelope("site1", subRequest), subscriberProbe.Ref);

        // Simulate site disconnection
        centralActor.Tell(new ConnectionStateChanged("site1", false, DateTimeOffset.UtcNow));

        // The subscriber should receive a DebugStreamTerminated notification
        subscriberProbe.ExpectMsg<DebugStreamTerminated>(
            msg => msg.SiteId == "site1" && msg.CorrelationId == "corr-123");
    }

    [Fact]
    public void ConnectionLost_SiteSelectionRemoved()
    {
        var centralActor = Sys.ActorOf(Props.Create(() => new CentralCommunicationActor()));
        var siteProbe = CreateTestProbe();

        centralActor.Tell(new RegisterSite("site1", siteProbe.Ref.Path.ToString()));

        // Disconnect
        centralActor.Tell(new ConnectionStateChanged("site1", false, DateTimeOffset.UtcNow));

        // Sending a message to the disconnected site should be dropped
        centralActor.Tell(new SiteEnvelope("site1",
            new DeployInstanceCommand("dep2", "inst2", "hash2", "{}", "admin", DateTimeOffset.UtcNow)));

        siteProbe.ExpectNoMsg(TimeSpan.FromMilliseconds(200));
    }

    [Fact]
    public void Heartbeat_ForwardedToParent()
    {
        var parentProbe = CreateTestProbe();
        var centralActor = parentProbe.ChildActorOf(
            Props.Create(() => new CentralCommunicationActor()));

        var heartbeat = new HeartbeatMessage("site1", "host1", true, DateTimeOffset.UtcNow);
        centralActor.Tell(heartbeat);

        parentProbe.ExpectMsg<HeartbeatMessage>(msg => msg.SiteId == "site1");
    }
}