using Shouldly;
using ZB.MOM.WW.OtOpcUa.Tests;
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 with no teardown first (the <c>IDriver</c> contract
///     allows it) 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(ITestOutputHelper output)
{
    /// <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 FixtureCleanup.RunAsync(async () =>
        {
            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
        }, () => drv.ShutdownAsync(CancellationToken.None),
            failure => output.WriteLine($"FOCAS SecondInitialize cleanup failed: {failure}"));
    }


    /// <summary>Failure after a live first or replacement state must release both owned resources.</summary>
    [Theory]
    [InlineData(false)]
    [InlineData(true)]
    public async Task Body_failure_releases_live_probe_resources(bool afterReplacement)
    {
        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);
        Task? firstLoop = null, secondLoop = null;
        FakeFocasClient? firstClient = null, secondClient = null;
        var sentinel = new InvalidOperationException("body sentinel");
        var actual = await Should.ThrowAsync<InvalidOperationException>(() => FixtureCleanup.RunAsync(async () =>
        {
            await drv.InitializeAsync("{}", CancellationToken.None);
            await WaitUntilAsync(() => factory.Clients.Count > 0 && factory.Clients[0].IsConnected);
            firstClient = factory.Clients[0];
            firstLoop = drv.GetDeviceState(host)!.ProbeTask;
            _ = firstLoop.ShouldNotBeNull();
            firstLoop!.IsCompleted.ShouldBeFalse();
            if (afterReplacement)
            {
                await drv.InitializeAsync("{}", CancellationToken.None);
                await WaitUntilAsync(() => factory.Clients.Count > 1 && factory.Clients[1].IsConnected);
                secondClient = factory.Clients[1];
                secondLoop = drv.GetDeviceState(host)!.ProbeTask;
                _ = secondLoop.ShouldNotBeNull();
                secondLoop!.IsCompleted.ShouldBeFalse();
            }
            throw sentinel;
        }, () => drv.ShutdownAsync(CancellationToken.None),
            failure => output.WriteLine($"FOCAS failure fixture cleanup failed: {failure}")));
        actual.ShouldBeSameAs(sentinel);
        firstLoop!.IsCompleted.ShouldBeTrue();
        firstClient!.DisposeCount.ShouldBeGreaterThanOrEqualTo(1);
        firstClient.IsConnected.ShouldBeFalse();
        if (afterReplacement)
        {
            secondLoop!.IsCompleted.ShouldBeTrue();
            secondClient!.DisposeCount.ShouldBeGreaterThanOrEqualTo(1);
            secondClient.IsConnected.ShouldBeFalse();
        }
    }

    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);
        }
    }
}