using Shouldly;
using ZB.MOM.WW.OtOpcUa.Tests;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.PlcFamilies;

namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.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 + runtime. It now releases them first.
/// </summary>
[Trait("Category", "Unit")]
public sealed class AbLegacyReinitializeReleasesStateTests(ITestOutputHelper output)
{
    /// <summary>Initialize twice: the first state's probe loop has stopped and its probe runtime is disposed.</summary>
    [Fact]
    public async Task SecondInitialize_StopsFirstStatesLoop_AndDisposesItsRuntime()
    {
        const string host = "ab://10.0.0.5/1,0";
        var factory = new FakeAbLegacyTagFactory();
        var drv = new AbLegacyDriver(new AbLegacyDriverOptions
        {
            Devices = [new AbLegacyDeviceOptions(host, AbLegacyPlcFamily.Slc500)],
            Probe = new AbLegacyProbeOptions { Enabled = true, Interval = TimeSpan.FromMilliseconds(20), ProbeAddress = "S:0" },
        }, "drv-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 running and has created + initialised its runtime.
            var deadline = DateTime.UtcNow.AddSeconds(5);
            while (!(factory.Tags.TryGetValue("S:0", out var t) && t.InitializeCount > 0))
            {
                if (DateTime.UtcNow > deadline) throw new TimeoutException("probe never started");
                await Task.Delay(10);
            }
            var firstTag = factory.Tags["S:0"];
            var firstLoop = first.ProbeTask;
            _ = firstLoop.ShouldNotBeNull();
            firstLoop!.IsCompleted.ShouldBeFalse();
            firstTag.Disposed.ShouldBeFalse();

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

            firstLoop.IsCompleted.ShouldBeTrue(); // joined
            firstTag.Disposed.ShouldBeTrue();
            drv.GetDeviceState(host).ShouldNotBeSameAs(first);
        }, () => drv.ShutdownAsync(CancellationToken.None),
            failure => output.WriteLine($"AbLegacy 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 = "ab://10.0.0.5/1,0";
        var factory = new FakeAbLegacyTagFactory();
        var drv = new AbLegacyDriver(new AbLegacyDriverOptions
        {
            Devices = [new AbLegacyDeviceOptions(host, AbLegacyPlcFamily.Slc500)],
            Probe = new AbLegacyProbeOptions { Enabled = true, Interval = TimeSpan.FromMilliseconds(20), ProbeAddress = "S:0" },
        }, "drv-reinit", factory);
        Task? firstLoop = null, secondLoop = null;
        FakeAbLegacyTag? firstTag = null, secondTag = null;
        var sentinel = new InvalidOperationException("body sentinel");
        var actual = await Should.ThrowAsync<InvalidOperationException>(() => FixtureCleanup.RunAsync(async () =>
        {
            await drv.InitializeAsync("{}", CancellationToken.None);
            await WaitForProbeAsync(() => factory.Tags.TryGetValue("S:0", out var tag) && tag.InitializeCount > 0);
            firstTag = factory.Tags["S:0"];
            firstLoop = drv.GetDeviceState(host)!.ProbeTask;
            _ = firstLoop.ShouldNotBeNull();
            firstLoop!.IsCompleted.ShouldBeFalse();
            firstTag.Disposed.ShouldBeFalse();
            if (afterReplacement)
            {
                await drv.InitializeAsync("{}", CancellationToken.None);
                await WaitForProbeAsync(() => factory.Tags.TryGetValue("S:0", out var tag) && !ReferenceEquals(tag, firstTag) && tag.InitializeCount > 0);
                secondTag = factory.Tags["S:0"];
                secondLoop = drv.GetDeviceState(host)!.ProbeTask;
                _ = secondLoop.ShouldNotBeNull();
                secondLoop!.IsCompleted.ShouldBeFalse();
            }
            throw sentinel;
        }, () => drv.ShutdownAsync(CancellationToken.None),
            failure => output.WriteLine($"AbLegacy failure fixture cleanup failed: {failure}")));
        actual.ShouldBeSameAs(sentinel);
        firstLoop!.IsCompleted.ShouldBeTrue();
        firstTag!.Disposed.ShouldBeTrue();
        if (afterReplacement)
        {
            secondLoop!.IsCompleted.ShouldBeTrue();
            secondTag!.Disposed.ShouldBeTrue();
        }
    }

    private static async Task WaitForProbeAsync(Func<bool> condition)
    {
        var deadline = DateTime.UtcNow.AddSeconds(5);
        while (!condition())
        {
            if (DateTime.UtcNow > deadline) throw new TimeoutException("probe never started");
            await Task.Delay(10);
        }
    }

}