using System.Collections.Immutable;
using Akka.Actor;
using Akka.Cluster.Tools.Client;
using Akka.Configuration;
using Akka.TestKit.Xunit2;
using Microsoft.Extensions.DependencyInjection;
using NSubstitute;
using Xunit;
using ZB.MOM.WW.ScadaBridge.Commons.Entities.Sites;
using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Repositories;
using ZB.MOM.WW.ScadaBridge.Communication;
using ZB.MOM.WW.ScadaBridge.Communication.Actors;
using ZB.MOM.WW.ScadaBridge.HealthMonitoring;

namespace ZB.MOM.WW.ScadaBridge.Communication.Tests;

public class CentralCommunicationActorClientLifecycleTests : TestKit
{
    private static readonly Config TestConfig = ConfigurationFactory.ParseString(@"
        akka.actor.provider = cluster
        akka.remote.dot-netty.tcp.port = 0
        akka.remote.dot-netty.tcp.hostname = localhost")
        .WithFallback(ClusterClientReceptionist.DefaultConfig());

    public CentralCommunicationActorClientLifecycleTests() : base(TestConfig) { }

    // Empty ServiceProvider with a no-op ISiteRepository so the actor's periodic
    // db-refresh (fired at PreStart) resolves and returns no sites, keeping the
    // logs clean; the tests drive SiteAddressCacheLoaded directly.
    private static IServiceProvider EmptyProvider()
    {
        var siteRepo = Substitute.For<ISiteRepository>();
        siteRepo.GetAllSitesAsync(Arg.Any<CancellationToken>()).Returns(new List<Site>());
        var services = new ServiceCollection();
        services.AddScoped(_ => siteRepo);
        return services.BuildServiceProvider();
    }

    private static SiteAddressCacheLoaded Load(string siteId, params string[] addrs) =>
        new(new Dictionary<string, IReadOnlyList<string>>
            { [siteId] = addrs.ToList().AsReadOnly() },
            new[] { siteId });

    [Fact]
    public void PeriodicRefresh_PrunesDeletedSites_FromHealthAggregator()
    {
        // PLAN-01 Task 18: the periodic site refresh feeds the currently-configured
        // site ids to the aggregator so a deleted site is evicted within one
        // refresh interval. Repo returns only "site-a".
        var siteRepo = Substitute.For<ISiteRepository>();
        siteRepo.GetAllSitesAsync(Arg.Any<CancellationToken>())
            .Returns(new List<Site> { new("Site A", "site-a") });
        var aggregator = Substitute.For<ICentralHealthAggregator>();
        var services = new ServiceCollection();
        services.AddScoped(_ => siteRepo);
        services.AddSingleton(aggregator);
        var provider = services.BuildServiceProvider();

        var actor = Sys.ActorOf(Props.Create(() => new CentralCommunicationActor(
            provider, new DefaultSiteClientFactory(), null)));

        // Trigger the refresh (also fires at PreStart, but drive it explicitly so
        // the assertion is deterministic). The load runs on a detached task and
        // pipes SiteAddressCacheLoaded back to the actor, which then prunes.
        actor.Tell(new RefreshSiteAddresses());

        AwaitAssert(
            () => aggregator.Received().PruneUnknownSites(
                Arg.Is<IReadOnlyCollection<string>>(ids => ids.Contains("site-a"))),
            TimeSpan.FromSeconds(3));
    }

    [Fact]
    public void AddressEdit_RecreatesClient_WithoutRestartLoop()
    {
        var actor = Sys.ActorOf(Props.Create(() => new CentralCommunicationActor(
            EmptyProvider(), new DefaultSiteClientFactory(), null)));

        // First load creates the client; second load (edited NodeA address) stops
        // the old one and creates a replacement in the same message handling.
        // Pre-fix this throws InvalidActorNameException and restarts the actor.
        EventFilter.Exception<InvalidActorNameException>().Expect(0, () =>
        {
            actor.Tell(Load("site-a", "akka.tcp://scadabridge@node-a:8081"));
            actor.Tell(Load("site-a", "akka.tcp://scadabridge@node-a-edited:8081"));
            actor.Tell(Load("site-a", "akka.tcp://scadabridge@node-a:8081")); // and back — third generation
        });

        // The actor must still be alive and routing (not crash-looping):
        // an envelope for an unknown site produces the "No ClusterClient" warning,
        // proving the Receive pipeline is healthy.
        EventFilter.Warning(contains: "No ClusterClient for site").ExpectOne(() =>
            actor.Tell(new SiteEnvelope("unknown-site", new object())));
    }

    [Fact]
    public void FactoryThrow_SkipsSite_DoesNotCrashActor()
    {
        var throwingFactory = Substitute.For<ISiteClientFactory>();
        throwingFactory.Create(Arg.Any<ActorSystem>(), Arg.Any<string>(), Arg.Any<ImmutableHashSet<ActorPath>>())
            .Returns(_ => throw new InvalidOperationException("boom"));
        var actor = Sys.ActorOf(Props.Create(() => new CentralCommunicationActor(
            EmptyProvider(), throwingFactory, null)));

        EventFilter.Error(contains: "Failed to create ClusterClient").ExpectOne(() =>
            actor.Tell(Load("site-a", "akka.tcp://scadabridge@node-a:8081")));

        // Actor survived — a subsequent envelope for that (unrouted) site still
        // produces the healthy "No ClusterClient" warning rather than a dead actor.
        EventFilter.Warning(contains: "No ClusterClient for site").ExpectOne(() =>
            actor.Tell(new SiteEnvelope("site-a", new object())));
    }
}