using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;

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

/// <summary>
///     Review 02 P1: AbLegacy ran <see cref="PollGroupEngine"/> but did not implement <see cref="IBatchSubscribable"/>,
///     so every changed tag paid its own trip through the actor chain. It now raises one
///     <see cref="IBatchSubscribable.OnDataChangeBatch"/> per poll cycle, alongside the per-tag event.
/// </summary>
[Trait("Category", "Unit")]
public sealed class AbLegacyBatchSubscribeTests
{
    private const string Host = "ab://10.0.0.5/1,0";

    [Fact]
    public async Task One_batch_per_poll_carries_every_changed_tag_and_per_tag_events_still_fire()
    {
        var factory = new FakeAbLegacyTagFactory { Customise = p => new FakeAbLegacyTag(p) { Value = p.TagName == "N7:0" ? 1 : 2 } };
        var drv = new AbLegacyDriver(new AbLegacyDriverOptions
        {
            Devices = [new AbLegacyDeviceOptions(Host)],
            RawTags = AbLegacyRawTags.Entries(
                new AbLegacyTagDefinition("A", Host, "N7:0", AbLegacyDataType.Int),
                new AbLegacyTagDefinition("B", Host, "N9:0", AbLegacyDataType.Int)),
            Probe = new AbLegacyProbeOptions { Enabled = false },
        }, "drv-batch", factory);
        await drv.InitializeAsync("{}", CancellationToken.None);
        IBatchSubscribable batching = drv; // the capability the actor prefers

        var batches = new System.Collections.Concurrent.ConcurrentQueue<DataChangeBatchEventArgs>();
        var singles = new System.Collections.Concurrent.ConcurrentQueue<DataChangeEventArgs>();
        batching.OnDataChangeBatch += (_, e) => batches.Enqueue(e);
        drv.OnDataChange += (_, e) => singles.Enqueue(e);

        var handle = await drv.SubscribeAsync(["A", "B"], TimeSpan.FromMilliseconds(100), CancellationToken.None);
        var deadline = DateTime.UtcNow.AddSeconds(5);
        while (batches.IsEmpty && DateTime.UtcNow < deadline) await Task.Delay(10, TestContext.Current.CancellationToken);

        batches.TryPeek(out var first).ShouldBeTrue();
        first!.SubscriptionHandle.ShouldBe(handle);
        first.Items.Select(i => i.FullReference).ShouldBe(new[] { "A", "B" }, ignoreOrder: true);
        first.Items.Single(i => i.FullReference == "A").Snapshot.Value.ShouldBe(1);
        singles.Count.ShouldBeGreaterThanOrEqualTo(2); // positive control: the legacy per-tag event still fires

        await drv.UnsubscribeAsync(handle, CancellationToken.None);
        await drv.ShutdownAsync(CancellationToken.None);
    }
}