using Akka.Actor;
using Akka.Configuration;
using ZB.MOM.WW.ScadaBridge.Host.Health;

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

public class ClusterActivityEvaluatorTests : IAsyncLifetime
{
    private ActorSystem? _system;

    public async Task InitializeAsync()
    {
        var port = FreePort();
        var config = ConfigurationFactory.ParseString($@"
akka {{
    actor.provider = cluster
    remote.dot-netty.tcp {{ hostname = ""127.0.0.1"", port = {port} }}
    cluster {{
        seed-nodes = [""akka.tcp://eval-test@127.0.0.1:{port}""]
        roles = [""Central""]
        min-nr-of-members = 1
    }}
}}");
        _system = ActorSystem.Create("eval-test", config);
        var cluster = Akka.Cluster.Cluster.Get(_system);
        var deadline = DateTime.UtcNow.AddSeconds(20);
        while (cluster.SelfMember.Status != Akka.Cluster.MemberStatus.Up && DateTime.UtcNow < deadline)
            await Task.Delay(100);
    }

    public async Task DisposeAsync() { if (_system != null) await _system.Terminate(); }

    [Fact]
    public void SelfIsOldest_SoleUpMember_ReturnsTrue()
    {
        var cluster = Akka.Cluster.Cluster.Get(_system!);
        Assert.True(ClusterActivityEvaluator.SelfIsOldest(cluster));
        Assert.True(ClusterActivityEvaluator.SelfIsOldest(cluster, "Central"));
    }

    [Fact]
    public void SelfIsOldest_RoleNotHeld_ReturnsFalse()
    {
        var cluster = Akka.Cluster.Cluster.Get(_system!);
        // Self doesn't carry the role => it can never host that role's singletons.
        Assert.False(ClusterActivityEvaluator.SelfIsOldest(cluster, "site-nonexistent"));
    }

    private static int FreePort()
    {
        var l = new System.Net.Sockets.TcpListener(System.Net.IPAddress.Loopback, 0);
        l.Start(); var p = ((System.Net.IPEndPoint)l.LocalEndpoint).Port; l.Stop(); return p;
    }
}