using System.Threading.Channels;
using Google.Protobuf.WellKnownTypes;
using MxGateway.Contracts.Proto;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Config;
using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Runtime;

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

/// <summary>
///     PR E.7 — pins that the GalaxyDriver populates the extended AlarmEventArgs
///     fields (OperatorComment, OriginalRaiseTimestampUtc, AlarmCategory) when the
///     gateway emits a transition with the rich payload, and leaves them null on
///     events that don't carry them.
/// </summary>
public sealed class GalaxyDriverAlarmEventArgsExtensionTests
{
    [Fact]
    public async Task Acknowledge_transition_with_full_payload_populates_extended_fields()
    {
        var subscriber = new ManualSubscriber();
        using var driver = NewDriver(subscriber);

        await driver.SubscribeAlarmsAsync(["Tank01"], CancellationToken.None);
        var observed = new List<AlarmEventArgs>();
        driver.OnAlarmEvent += (_, args) => observed.Add(args);
        await driver.SubscribeAsync(["Tank01.Level"], TimeSpan.Zero, CancellationToken.None);

        var raise = new DateTime(2026, 5, 1, 12, 0, 0, DateTimeKind.Utc);
        var ack = raise.AddSeconds(45);
        await subscriber.EmitAlarmAsync(new MxEvent
        {
            Family = MxEventFamily.OnAlarmTransition,
            OnAlarmTransition = new OnAlarmTransitionEvent
            {
                AlarmFullReference = "Tank01.Level.HiHi",
                SourceObjectReference = "Tank01",
                AlarmTypeName = "AnalogLimitAlarm.HiHi",
                TransitionKind = AlarmTransitionKind.Acknowledge,
                Severity = 750,
                OriginalRaiseTimestamp = Timestamp.FromDateTime(raise),
                TransitionTimestamp = Timestamp.FromDateTime(ack),
                OperatorUser = "alice",
                OperatorComment = "investigating",
                Category = "Process",
                Description = "Tank 01 high-high level",
            },
        });

        for (var i = 0; i < 20 && observed.Count == 0; i++)
        {
            await Task.Delay(50);
        }
        observed.ShouldHaveSingleItem();
        observed[0].OperatorComment.ShouldBe("investigating");
        observed[0].OriginalRaiseTimestampUtc.ShouldBe(raise);
        observed[0].AlarmCategory.ShouldBe("Process");
    }

    [Fact]
    public async Task Raise_transition_without_optional_fields_leaves_them_null()
    {
        var subscriber = new ManualSubscriber();
        using var driver = NewDriver(subscriber);

        await driver.SubscribeAlarmsAsync(["Tank01"], CancellationToken.None);
        var observed = new List<AlarmEventArgs>();
        driver.OnAlarmEvent += (_, args) => observed.Add(args);
        await driver.SubscribeAsync(["Tank01.Level"], TimeSpan.Zero, CancellationToken.None);

        await subscriber.EmitAlarmAsync(new MxEvent
        {
            Family = MxEventFamily.OnAlarmTransition,
            OnAlarmTransition = new OnAlarmTransitionEvent
            {
                AlarmFullReference = "Tank01.Level.HiHi",
                AlarmTypeName = "AnalogLimitAlarm.HiHi",
                TransitionKind = AlarmTransitionKind.Raise,
                Severity = 750,
                TransitionTimestamp = Timestamp.FromDateTime(DateTime.UtcNow),
            },
        });

        for (var i = 0; i < 20 && observed.Count == 0; i++)
        {
            await Task.Delay(50);
        }
        observed.ShouldHaveSingleItem();
        observed[0].OperatorComment.ShouldBeNull();
        observed[0].OriginalRaiseTimestampUtc.ShouldBeNull();
        observed[0].AlarmCategory.ShouldBeNull();
    }

    private static GalaxyDriver NewDriver(ManualSubscriber subscriber)
    {
        var options = new GalaxyDriverOptions(
            new GalaxyGatewayOptions("http://localhost:5000", "literal-api-key"),
            new GalaxyMxAccessOptions("AlarmExtensionTest"),
            new GalaxyRepositoryOptions(),
            new GalaxyReconnectOptions());
        return new GalaxyDriver(
            driverInstanceId: "drv-1",
            options: options,
            hierarchySource: null,
            dataReader: null,
            dataWriter: null,
            subscriber: subscriber,
            alarmAcknowledger: null);
    }

    private sealed class ManualSubscriber : IGalaxySubscriber
    {
        private readonly Channel<MxEvent> _stream =
            Channel.CreateUnbounded<MxEvent>(new UnboundedChannelOptions { SingleReader = true });

        public Task<IReadOnlyList<SubscribeResult>> SubscribeBulkAsync(
            IReadOnlyList<string> fullReferences, int bufferedUpdateIntervalMs, CancellationToken cancellationToken)
        {
            var results = new List<SubscribeResult>();
            var nextHandle = 100;
            foreach (var r in fullReferences)
            {
                results.Add(new SubscribeResult { TagAddress = r, ItemHandle = nextHandle++, WasSuccessful = true });
            }
            return Task.FromResult<IReadOnlyList<SubscribeResult>>(results);
        }

        public Task UnsubscribeBulkAsync(IReadOnlyList<int> itemHandles, CancellationToken cancellationToken)
            => Task.CompletedTask;

        public IAsyncEnumerable<MxEvent> StreamEventsAsync(CancellationToken cancellationToken)
            => _stream.Reader.ReadAllAsync(cancellationToken);

        public ValueTask EmitAlarmAsync(MxEvent ev) => _stream.Writer.WriteAsync(ev);
    }
}