using Akka.Cluster;
using Akka.TestKit.Xunit2;
using Microsoft.EntityFrameworkCore;
using ZB.MOM.WW.OtOpcUa.Configuration;

namespace ZB.MOM.WW.OtOpcUa.ControlPlane.Tests.Harness;

/// <summary>
/// Akka TestKit fixture for ControlPlane actor tests. Provides:
/// - A test ActorSystem (xunit2 TestKit) wired with PubSub/Cluster extensions.
/// - A fresh in-memory <see cref="OtOpcUaConfigDbContext"/> per harness instance.
/// - An <see cref="IDbContextFactory{TContext}"/> the actors can hold.
///
/// One harness per test fact — InMemory provider gives strong isolation when the database
/// name is unique (random Guid).
/// </summary>
public abstract class ControlPlaneActorTestBase : TestKit
{
    /// <summary>
    ///     Shared upper bound for a <b>presence</b> wait (<c>ExpectMsg</c> / <c>ExpectTerminated</c> /
    ///     <c>AwaitAssert</c>) — the same doctrine as <c>RuntimeActorTestBase.PresenceBudget</c>.
    /// </summary>
    /// <remarks>
    ///     A budget, not a delay: the helpers return the instant the condition holds, so raising it costs
    ///     nothing on the happy path and cannot make a genuinely failing assertion pass. Several actors here
    ///     do their first EF Core (InMemory) work inside the waited-for step — model build is a multi-second
    ///     cold cost on a loaded CI runner — and 3–5 s budgets sized on an idle machine failed there (#606).
    ///     Absence windows (<c>ExpectNoMsg</c>) keep their own short literals and must not use this.
    /// </remarks>
    protected static readonly TimeSpan PresenceBudget = TimeSpan.FromSeconds(15);

    /// <summary>Gets the Akka configuration for test actors, including cluster and pub-sub extensions.</summary>
    /// <remarks>
    ///     <c>akka.test.single-expect-default</c> is raised from Akka's 3 s to <see cref="PresenceBudget"/>:
    ///     it is the budget every duration-less <c>ExpectMsg</c>/<c>ExpectTerminated</c>/<c>AwaitAssert</c>
    ///     uses, all of which are presence waits. Nothing in this assembly calls a duration-less
    ///     <c>ExpectNoMsg()</c>, the one absence wait that would also read it.
    ///     <para><c>akka.test.timefactor</c> comes from <see cref="TestTimeFactor"/>.</para>
    /// </remarks>
    protected static string AkkaTestHocon => BaseHocon + TestTimeFactor.Hocon;

    private const string BaseHocon = @"
akka {
    loglevel = ""WARNING""
    test.single-expect-default = 15s
    extensions = [
        ""Akka.Cluster.Tools.PublishSubscribe.DistributedPubSubExtensionProvider, Akka.Cluster.Tools""
    ]
    actor {
        provider = ""Akka.Cluster.ClusterActorRefProvider, Akka.Cluster""
    }
    remote.dot-netty.tcp {
        hostname = ""127.0.0.1""
        port = 0
    }
    cluster {
        seed-nodes = []
        roles = [""admin""]
        min-nr-of-members = 1
        run-coordinated-shutdown-when-down = off
        pub-sub.role = """"
    }
}";

    /// <summary>Initializes a new instance of the test harness; joins the cluster and waits for up status.</summary>
    protected ControlPlaneActorTestBase() : base(AkkaTestHocon)
    {
        // Self-join so the cluster transitions to Up and DistributedPubSub forms.
        var cluster = Akka.Cluster.Cluster.Get(Sys);
        cluster.Join(cluster.SelfAddress);
        AwaitCondition(() => cluster.State.Members.Any(m => m.Status == MemberStatus.Up),
            TimeSpan.FromSeconds(5));
    }

    /// <summary>Creates a new in-memory database context factory with an optional database name.</summary>
    /// <param name="dbName">Optional database name; defaults to a random GUID if not provided.</param>
    /// <returns>A context factory for creating in-memory config database contexts.</returns>
    protected static IDbContextFactory<OtOpcUaConfigDbContext> NewInMemoryDbFactory(string? dbName = null)
    {
        dbName ??= Guid.NewGuid().ToString("N");
        return new InMemoryConfigDbFactory(dbName);
    }

    private sealed class InMemoryConfigDbFactory(string dbName) : IDbContextFactory<OtOpcUaConfigDbContext>
    {
        /// <summary>Creates a new in-memory database context.</summary>
        /// <returns>A new OtOpcUaConfigDbContext instance.</returns>
        public OtOpcUaConfigDbContext CreateDbContext()
        {
            var opts = new DbContextOptionsBuilder<OtOpcUaConfigDbContext>()
                .UseInMemoryDatabase(dbName)
                .Options;
            return new OtOpcUaConfigDbContext(opts);
        }
    }
}