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

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

/// <summary>
///     #630 — <c>InitializeAsync</c> on a live driver (<c>DriverInstanceActor.AdoptConfigDuringInit</c> runs
///     it with no teardown first) overwrote <c>_devices[host]</c> and orphaned the previous state's
///     probe loop + client. It now releases them first.
/// </summary>
[Trait("Category", "Unit")]
public sealed class FocasReinitializeReleasesStateTests
{
    /// <summary>Initialize twice: the first state's probe loop has finished and its client is disposed.</summary>
    [Fact]
    public async Task SecondInitialize_StopsFirstStatesLoop_AndDisposesItsClient()
    {
        const string host = "focas://10.0.0.5:8193";
        var factory = new FakeFocasClientFactory();
        var options = new FocasDriverOptions
        {
            Devices = [new FocasDeviceOptions(host)],
            RawTags = [FocasRawTags.Entry(new FocasTagDefinition("R", host, "R100", FocasDataType.Byte))],
            Probe = new FocasProbeOptions { Enabled = true, Interval = TimeSpan.FromMilliseconds(20), Timeout = TimeSpan.FromSeconds(2) },
        };
        var drv = new FocasDriver(options, "focas-reinit", factory);
        await drv.InitializeAsync("{}", CancellationToken.None);

        var first = drv.GetDeviceState(host)!;
        // Positive control: the first state's probe loop is demonstrably running and holds a live client.
        await WaitUntilAsync(() => factory.Clients.Count > 0 && factory.Clients[0].IsConnected);
        var firstLoop = first.ProbeTask;
        firstLoop.ShouldNotBeNull();
        firstLoop!.IsCompleted.ShouldBeFalse();
        var firstClient = factory.Clients[0];

        await drv.InitializeAsync("{}", CancellationToken.None);

        firstLoop.IsCompleted.ShouldBeTrue(); // joined
        firstClient.DisposeCount.ShouldBeGreaterThanOrEqualTo(1);
        firstClient.IsConnected.ShouldBeFalse();
        drv.GetDeviceState(host).ShouldNotBeSameAs(first);
        drv.GetDeviceState(host)!.ProbeTask.ShouldNotBeNull(); // the new state is running

        await drv.ShutdownAsync(CancellationToken.None);
    }

    private static async Task WaitUntilAsync(Func<bool> cond)
    {
        var deadline = DateTime.UtcNow.AddSeconds(5);
        while (!cond())
        {
            if (DateTime.UtcNow > deadline) throw new TimeoutException("condition not met");
            await Task.Delay(10);
        }
    }
}