using Akka.Actor;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Commons.Types;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.Runtime.Drivers;
using ZB.MOM.WW.OtOpcUa.Runtime.Tests.Harness;

namespace ZB.MOM.WW.OtOpcUa.Runtime.Tests.Drivers;

public sealed class DriverInstanceActorTests : RuntimeActorTestBase
{
    [Fact]
    public async Task ApplyDelta_when_Connected_calls_ReinitializeAsync_and_replies_success()
    {
        var driver = new StubDriver();
        var actor = Sys.ActorOf(DriverInstanceActor.Props(driver));

        // Drive: Initialize → Connected.
        actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
        AwaitCondition(() => driver.InitializeCount > 0, TimeSpan.FromSeconds(2));

        // Issue ApplyDelta and capture the reply via Ask.
        var correlation = CorrelationId.NewId();
        var reply = await actor.Ask<DriverInstanceActor.ApplyResult>(
            new DriverInstanceActor.ApplyDelta("{\"changed\":true}", correlation),
            TimeSpan.FromSeconds(3));

        reply.Success.ShouldBeTrue();
        reply.Correlation.ShouldBe(correlation);
        driver.ReinitializeCount.ShouldBe(1);
    }

    [Fact]
    public void Initialize_failure_keeps_actor_in_Reconnecting_state()
    {
        var driver = new StubDriver { InitializeShouldThrow = true };
        var actor = Sys.ActorOf(DriverInstanceActor.Props(driver, reconnectInterval: TimeSpan.FromMilliseconds(50)));

        actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));

        // The actor should keep trying — we expect multiple Initialize calls because the
        // reconnect timer fires every 50ms.
        AwaitCondition(() => driver.InitializeCount >= 3, TimeSpan.FromSeconds(2));
    }

    [Fact]
    public async Task Write_against_non_IWritable_driver_returns_failure()
    {
        var driver = new StubDriver(); // IDriver only, no IWritable.
        var actor = Sys.ActorOf(DriverInstanceActor.Props(driver));

        actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
        AwaitCondition(() => driver.InitializeCount > 0, TimeSpan.FromSeconds(2));

        var reply = await actor.Ask<DriverInstanceActor.WriteAttributeResult>(
            new DriverInstanceActor.WriteAttribute("tag-1", 42),
            TimeSpan.FromSeconds(3));

        reply.Success.ShouldBeFalse();
        reply.Reason!.ShouldContain("IWritable");
    }

    private sealed class StubDriver : IDriver
    {
        public bool InitializeShouldThrow { get; set; }
        public int InitializeCount;
        public int ReinitializeCount;

        public string DriverInstanceId => "stub-driver-1";
        public string DriverType => "Stub";

        public Task InitializeAsync(string driverConfigJson, CancellationToken cancellationToken)
        {
            Interlocked.Increment(ref InitializeCount);
            if (InitializeShouldThrow) throw new InvalidOperationException("stub-init-fail");
            return Task.CompletedTask;
        }

        public Task ReinitializeAsync(string driverConfigJson, CancellationToken cancellationToken)
        {
            Interlocked.Increment(ref ReinitializeCount);
            return Task.CompletedTask;
        }

        public Task ShutdownAsync(CancellationToken cancellationToken) => Task.CompletedTask;
        public DriverHealth GetHealth() => new(DriverState.Healthy, DateTime.UtcNow, null);
        public long GetMemoryFootprint() => 0;
        public Task FlushOptionalCachesAsync(CancellationToken cancellationToken) => Task.CompletedTask;
    }
}