using Akka.Actor;
using Akka.TestKit;
using Akka.TestKit.Xunit2;
using Microsoft.Extensions.Logging.Abstractions;
using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Protocol;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.DataConnection;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.Instance;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.Streaming;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Flattening;
using ZB.MOM.WW.ScadaBridge.SiteRuntime.Actors;
using ZB.MOM.WW.ScadaBridge.SiteRuntime.Persistence;
using ZB.MOM.WW.ScadaBridge.SiteRuntime.Scripts;
using ZB.MOM.WW.ScadaBridge.SiteRuntime.Streaming;
using ZB.MOM.WW.ScadaBridge.TestSupport;
using System.Text.Json;

namespace ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests.Actors;

/// <summary>
/// Flow Debugger design 2026-09-05 §5.3 — the Instance Actor trace arm: a TRACED write to a
/// data-sourced attribute stamps the next DCL echo for that attribute with the writer's
/// <c>SourceExecutionId</c> and <c>Trace</c>; the arm is consumed once and expires unconsumed.
/// Untraced writes never arm (the production-unchanged pin). A traced static write publishes
/// the flag directly.
/// </summary>
public class InstanceActorTraceArmTests : TestKit, IDisposable
{
    private const string Tag = "ns=3;s=Recipe.Processed";
    private readonly SiteStorageService _storage;
    private readonly ScriptCompilationService _compilationService;
    private readonly SharedScriptLibrary _sharedScriptLibrary;
    private readonly TestLocalDb _localDb;

    public InstanceActorTraceArmTests()
    {
        _localDb = TestLocalDb.CreateTemp("instance-tracearm-test");
        _storage = new SiteStorageService(_localDb.Db, NullLogger<SiteStorageService>.Instance);
        _storage.InitializeAsync().GetAwaiter().GetResult();
        _compilationService = new ScriptCompilationService(NullLogger<ScriptCompilationService>.Instance);
        _sharedScriptLibrary = new SharedScriptLibrary(_compilationService, NullLogger<SharedScriptLibrary>.Instance);
    }

    void IDisposable.Dispose()
    {
        Shutdown();
        var path = _localDb.Path;
        _localDb.Dispose();
        TestLocalDb.DeleteFiles(path);
    }

    private static FlattenedConfiguration Config(string instance) => new()
    {
        InstanceUniqueName = instance,
        Attributes =
        [
            new ResolvedAttribute
            {
                CanonicalName = "Processed", Value = "false", DataType = "Boolean",
                DataSourceReference = Tag, BoundDataConnectionName = "PLC"
            },
            new ResolvedAttribute { CanonicalName = "Status", Value = "Idle", DataType = "String" },
        ]
    };

    private (IActorRef Actor, TestProbe Dcl, TestProbe Subscriber) Create(string instance, int armWindowSeconds = 30)
    {
        var options = new SiteRuntimeOptions { StreamBufferSize = 100, TraceArmWindowSeconds = armWindowSeconds };
        var streamManager = new SiteStreamManager(options, NullLogger<SiteStreamManager>.Instance);
        streamManager.Initialize(Sys);
        var dcl = CreateTestProbe();
        var actor = ActorOf(Props.Create(() => new InstanceActor(
            instance, JsonSerializer.Serialize(Config(instance)), _storage, _compilationService,
            _sharedScriptLibrary, streamManager, options, NullLogger<InstanceActor>.Instance, dcl.Ref)));
        var subscriber = CreateTestProbe();
        streamManager.Subscribe(instance, subscriber.Ref);
        return (actor, dcl, subscriber);
    }

    private static WriteTagRequest ExpectWrite(TestProbe dcl)
        => dcl.FishForMessage<WriteTagRequest>(_ => true, TimeSpan.FromSeconds(5));

    private void Write(IActorRef actor, TestProbe dcl, string instance, Guid? source, bool trace)
    {
        actor.Tell(new SetStaticAttributeCommand("c", instance, "Processed", "true", DateTimeOffset.UtcNow,
            SourceExecutionId: source, Trace: trace));
        var write = ExpectWrite(dcl);
        Assert.Equal(Tag, write.TagPath);
        dcl.Reply(new WriteTagResponse(write.CorrelationId, true, null, DateTimeOffset.UtcNow));
        Assert.True(ExpectMsg<SetStaticAttributeResponse>(TimeSpan.FromSeconds(5)).Success);
    }

    /// <summary>Same as <see cref="Write"/> but the DCL rejects the write, so the arm must be dropped.</summary>
    private void FailingWrite(IActorRef actor, TestProbe dcl, string instance, Guid? source, bool trace)
    {
        actor.Tell(new SetStaticAttributeCommand("c", instance, "Processed", "true", DateTimeOffset.UtcNow,
            SourceExecutionId: source, Trace: trace));
        var write = ExpectWrite(dcl);
        Assert.Equal(Tag, write.TagPath);
        dcl.Reply(new WriteTagResponse(write.CorrelationId, false, "rejected", DateTimeOffset.UtcNow));
        Assert.False(ExpectMsg<SetStaticAttributeResponse>(TimeSpan.FromSeconds(5)).Success);
    }

    private static AttributeValueChanged Echo(IActorRef actor, TestProbe subscriber, object? value)
    {
        actor.Tell(new TagValueUpdate("PLC", Tag, value, QualityCode.Good, DateTimeOffset.UtcNow));
        return subscriber.FishForMessage<AttributeValueChanged>(
            m => m.AttributeName == "Processed" && Equals(m.Value, value), TimeSpan.FromSeconds(10));
    }

    [Fact]
    public void TracedDataWrite_ThenEcho_PublishesChangeStampedWithSourceAndTrace()
    {
        var (actor, dcl, sub) = Create("P1");
        var writer = Guid.NewGuid();

        Write(actor, dcl, "P1", writer, trace: true);
        // The device clamps/echoes whatever it wants — the stamp does not depend on the value.
        var published = Echo(actor, sub, "clamped");

        Assert.Equal(writer, published.SourceExecutionId);
        Assert.True(published.Trace);
    }

    [Fact]
    public void UntracedDataWrite_ThenEcho_PublishesUnstampedChange()
    {
        var (actor, dcl, sub) = Create("P2");

        // Stamped writer but NOT traced — the ordinary script-write path.
        Write(actor, dcl, "P2", Guid.NewGuid(), trace: false);
        var published = Echo(actor, sub, true);

        Assert.Null(published.SourceExecutionId);
        Assert.False(published.Trace);
    }

    /// <summary>
    /// Arch-review F6: the arm is recorded when the write is ISSUED, not when the DCL acknowledges
    /// it. A write the device rejects must drop the arm, otherwise the next unrelated subscription
    /// update on that attribute is stamped with the debugger's execution id for the rest of the
    /// 30 s window — the Flow Debugger would draw a "device echo" of a write that never landed.
    /// </summary>
    [Fact]
    public void TracedDataWrite_ThatFails_DisarmsTheAttribute_SoTheNextEchoIsUnstamped()
    {
        var (actor, dcl, sub) = Create("P6");

        FailingWrite(actor, dcl, "P6", Guid.NewGuid(), trace: true);
        var published = Echo(actor, sub, "unrelated");

        Assert.Null(published.SourceExecutionId);
        Assert.False(published.Trace);
    }

    /// <summary>
    /// A failed write must only drop ITS OWN arm — a newer traced write that succeeded in the
    /// meantime owns the arm and keeps it (the disarm is keyed on the writer's execution id).
    /// </summary>
    [Fact]
    public void FailedWrite_DoesNotDisarm_AnArmTakenByALaterWriter()
    {
        var (actor, dcl, sub) = Create("P7");
        var loser = Guid.NewGuid();
        var winner = Guid.NewGuid();

        // Issue the traced write that will fail, but hold its DCL reply back. The reply goes to the
        // Ask's temporary ref, so capture it now — a later Reply() would answer the second write.
        actor.Tell(new SetStaticAttributeCommand("c1", "P7", "Processed", "true", DateTimeOffset.UtcNow,
            SourceExecutionId: loser, Trace: true));
        var first = ExpectWrite(dcl);
        var firstAsker = dcl.LastSender;

        // A second traced write lands and succeeds — it now owns the arm.
        Write(actor, dcl, "P7", winner, trace: true);

        // Only now does the first write fail; its disarm must not steal the winner's arm.
        firstAsker.Tell(new WriteTagResponse(first.CorrelationId, false, "rejected", DateTimeOffset.UtcNow), dcl.Ref);
        Assert.False(ExpectMsg<SetStaticAttributeResponse>(TimeSpan.FromSeconds(5)).Success);

        var published = Echo(actor, sub, "echo");
        Assert.Equal(winner, published.SourceExecutionId);
        Assert.True(published.Trace);
    }

    [Fact]
    public void Arm_IsConsumedOnce()
    {
        var (actor, dcl, sub) = Create("P3");
        var writer = Guid.NewGuid();

        Write(actor, dcl, "P3", writer, trace: true);
        var first = Echo(actor, sub, "one");
        var second = Echo(actor, sub, "two");

        Assert.Equal(writer, first.SourceExecutionId);
        Assert.True(first.Trace);
        Assert.Null(second.SourceExecutionId);
        Assert.False(second.Trace);
    }

    [Fact]
    [Trait("Category", "Slow")]
    public void Arm_Expired_IsIgnored()
    {
        var (actor, dcl, sub) = Create("P4", armWindowSeconds: 1);

        Write(actor, dcl, "P4", Guid.NewGuid(), trace: true);
        Thread.Sleep(1100);
        var published = Echo(actor, sub, true);

        Assert.Null(published.SourceExecutionId);
        Assert.False(published.Trace);
    }

    [Fact]
    public void StaticWrite_Traced_PublishesTraceFlag()
    {
        var (actor, _, sub) = Create("P5");
        var writer = Guid.NewGuid();

        actor.Tell(new SetStaticAttributeCommand("c", "P5", "Status", "Running", DateTimeOffset.UtcNow,
            SourceExecutionId: writer, Trace: true));
        Assert.True(ExpectMsg<SetStaticAttributeResponse>(TimeSpan.FromSeconds(5)).Success);

        var published = sub.FishForMessage<AttributeValueChanged>(
            m => m.AttributeName == "Status" && Equals(m.Value, "Running"), TimeSpan.FromSeconds(10));
        Assert.Equal(writer, published.SourceExecutionId);
        Assert.True(published.Trace);

        // And an untraced static write publishes Trace=false (pin).
        actor.Tell(new SetStaticAttributeCommand("c2", "P5", "Status", "Idle2", DateTimeOffset.UtcNow, SourceExecutionId: writer));
        ExpectMsg<SetStaticAttributeResponse>(TimeSpan.FromSeconds(5));
        var plain = sub.FishForMessage<AttributeValueChanged>(
            m => m.AttributeName == "Status" && Equals(m.Value, "Idle2"), TimeSpan.FromSeconds(10));
        Assert.False(plain.Trace);
    }
}