using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Driver.FOCAS;

namespace ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Tests;

/// <summary>
///     STAB-23 / #602 — the probe / recycle / fixed-tree loops were fire-and-forget, so shutdown
///     cancelled and disposed while a loop could still be parked inside a connect that ignores
///     cancellation, and that connect then completed against a shut-down driver. Shutdown now joins
///     the loops (bounded) before disposing the client.
/// </summary>
[Trait("Category", "Unit")]
public sealed class FocasShutdownJoinTests
{
    /// <summary>A client whose connect parks until released and deliberately ignores the cancellation token.</summary>
    private sealed class ParkedConnectClient(TaskCompletionSource entered, TaskCompletionSource release) : FakeFocasClient
    {
        public override async Task ConnectAsync(FocasHostAddress address, TimeSpan timeout, CancellationToken ct)
        {
            entered.TrySetResult();
            await release.Task.ConfigureAwait(false);
            await base.ConnectAsync(address, timeout, CancellationToken.None).ConfigureAwait(false);
        }
    }

    /// <summary>Shutdown blocks on a probe loop parked in connect, then disposes the client that connect produced.</summary>
    [Fact]
    public async Task Shutdown_WaitsForLoopParkedInConnect_ThenDisposesItsClient()
    {
        var entered = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
        var release = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
        var factory = new FakeFocasClientFactory { Customise = () => new ParkedConnectClient(entered, release) };
        var options = new FocasDriverOptions
        {
            Devices = [new FocasDeviceOptions("focas://10.0.0.5:8193")],
            RawTags = [FocasRawTags.Entry(new FocasTagDefinition("R", "focas://10.0.0.5:8193", "R100", FocasDataType.Byte))],
            Probe = new FocasProbeOptions { Enabled = true, Interval = TimeSpan.FromMilliseconds(50), Timeout = TimeSpan.FromSeconds(10) },
        };
        var drv = new FocasDriver(options, "focas-1", factory);
        await drv.InitializeAsync("{}", CancellationToken.None);
        await entered.Task.WaitAsync(TimeSpan.FromSeconds(5));

        var shutdown = drv.ShutdownAsync(CancellationToken.None);

        await Task.Delay(300);
        shutdown.IsCompleted.ShouldBeFalse("shutdown must join the probe loop parked in connect");

        // Positive control: releasing the parked connect lets shutdown finish.
        release.SetResult();
        await shutdown.WaitAsync(TimeSpan.FromSeconds(5));

        factory.Clients.ShouldNotBeEmpty();
        factory.Clients.ShouldAllBe(c => c.DisposeCount >= 1);
        factory.Clients.ShouldAllBe(c => !c.IsConnected);
    }
}