using Akka.Actor;
using Akka.Hosting;
using Akka.TestKit.Xunit;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.AdminUI.Clients;
using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
using ZB.MOM.WW.OtOpcUa.Runtime;
using ZB.MOM.WW.OtOpcUa.Runtime.Historian;

namespace ZB.MOM.WW.OtOpcUa.AdminUI.Tests;

/// <summary>
///     R04 L3: <c>/alarms-historian</c> distinguishes "this role runs no historian" (a permanent state, shown
///     once, not polled) from a sink that did not answer, instead of swallowing both into "Loading…" forever.
/// </summary>
[Trait("Category", "Unit")]
public sealed class AlarmsHistorianReaderTests : TestKit
{
    private static readonly HistorianSinkStatus Status = new(3, 1, null, null, null, HistorianDrainState.Idle);

    private sealed class StatusActor : ReceiveActor
    {
        public StatusActor() => Receive<HistorianAdapterActor.GetStatus>(_ => Sender.Tell(Status));
    }

    [Fact]
    public async Task An_answering_sink_is_available()
    {
        var actor = Sys.ActorOf(Props.Create(() => new StatusActor()));

        var reading = await HistorianSinkStatusReader.ReadAsync(() => actor, TimeSpan.FromSeconds(5), CancellationToken.None);

        reading.Availability.ShouldBe(HistorianSinkAvailability.Available);
        reading.Status.ShouldBe(Status);
    }

    [Fact]
    public async Task A_node_without_the_registry_entry_reports_not_on_this_role()
    {
        // The real Akka.Hosting registry: an admin-only node never registers the historian key.
        var registry = new ActorRegistry();

        var reading = await HistorianSinkStatusReader.ReadAsync(
            () => registry.Get<HistorianAdapterActorKey>(), TimeSpan.FromSeconds(5), CancellationToken.None);

        reading.Availability.ShouldBe(HistorianSinkAvailability.NotOnThisRole);
        reading.Status.ShouldBeNull();
        reading.Message!.ShouldContain("driver role");
    }

    [Fact]
    public async Task A_silent_sink_is_unavailable_not_loading()
    {
        var silent = CreateTestProbe(); // receives the Ask, never replies

        var reading = await HistorianSinkStatusReader.ReadAsync(() => silent.Ref, TimeSpan.FromMilliseconds(200), CancellationToken.None);

        reading.Availability.ShouldBe(HistorianSinkAvailability.Unavailable);
        reading.Message!.ShouldContain("did not answer");
        // Positive control: the Ask really was delivered — the classification is about the missing reply.
        silent.ExpectMsg<HistorianAdapterActor.GetStatus>(cancellationToken: TestContext.Current.CancellationToken);
    }

    [Fact]
    public async Task Page_teardown_cancellation_propagates()
    {
        var silent = CreateTestProbe();
        using var cts = new CancellationTokenSource();
        cts.Cancel();

        await Should.ThrowAsync<OperationCanceledException>(() =>
            HistorianSinkStatusReader.ReadAsync(() => silent.Ref, TimeSpan.FromSeconds(30), cts.Token));
    }

    [Fact]
    public void Not_registered_keeps_a_slow_repoll_instead_of_stopping()
    {
        // Review r0 M6: a driver node opened mid-startup is "not registered" for a moment — never permanent.
        HistorianSinkStatusReader.PollIntervalFor(HistorianSinkAvailability.NotOnThisRole)
            .ShouldBe(HistorianSinkStatusReader.NotRegisteredPollInterval);
        HistorianSinkStatusReader.PollIntervalFor(HistorianSinkAvailability.Available)
            .ShouldBe(HistorianSinkStatusReader.PollInterval);
        HistorianSinkStatusReader.PollIntervalFor(null).ShouldBe(HistorianSinkStatusReader.PollInterval);

        var src = AdminUiSource.Read("Components", "Pages", "AlarmsHistorian.razor");
        src.ShouldContain("_timer.Change(interval, interval)");
        src.ShouldNotContain("if (_reading?.Availability == HistorianSinkAvailability.NotOnThisRole) return;");
    }

    [Fact]
    public void Page_uses_the_reader_and_the_async_dispose_lifecycle()
    {
        var src = AdminUiSource.Read("Components", "Pages", "AlarmsHistorian.razor");
        src.ShouldContain("HistorianSinkStatusReader.ReadAsync(");
        src.ShouldContain("@implements IAsyncDisposable");
        src.ShouldContain("HistorianSinkAvailability.NotOnThisRole");
        System.Text.RegularExpressions.Regex.IsMatch(src, @"catch\s*\{").ShouldBeFalse("a bare catch {} swallows every failure");
    }
}