using Akka.Actor;
using Akka.TestKit.Xunit2;
using Microsoft.CodeAnalysis.CSharp.Scripting;
using Microsoft.CodeAnalysis.Scripting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging.Abstractions;
using ZB.MOM.WW.Audit;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.ScriptExecution;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.Streaming;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Audit;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Debugging;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Flattening;
using IAuditWriter = ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services.IAuditWriter;
using ZB.MOM.WW.ScadaBridge.SiteRuntime.Actors;
using ZB.MOM.WW.ScadaBridge.SiteRuntime.Scripts;

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

/// <summary>
/// Flow Debugger design 2026-09-05 §5.1/§5.4: a traced <see cref="ScriptCallRequest"/> makes
/// the launched run emit a <c>ScriptRun</c> row and return its <c>ExecutionId</c> plus the
/// inline trace events on the <see cref="ScriptCallResult"/>; a traced, stamped
/// <see cref="AttributeValueChanged"/> parents the value-change run to the writer. Untraced
/// paths are pinned unchanged.
/// </summary>
public class ScriptActorTraceTests : TestKit, IDisposable
{
    private sealed class CapturingAuditWriter : IAuditWriter
    {
        public List<AuditEvent> Events { get; } = new();
        public Task WriteAsync(AuditEvent evt, CancellationToken ct = default)
        {
            lock (Events) Events.Add(evt);
            return Task.CompletedTask;
        }
        public AuditEvent? WaitForKind(string action, TimeSpan timeout)
        {
            var deadline = DateTime.UtcNow + timeout;
            while (DateTime.UtcNow < deadline)
            {
                lock (Events)
                {
                    var hit = Events.FirstOrDefault(e => e.Action == action);
                    if (hit is not null) return hit;
                }
                Thread.Sleep(25);
            }
            return null;
        }
    }

    private readonly SharedScriptLibrary _sharedLibrary;
    private readonly SiteRuntimeOptions _options;
    private readonly ScriptExecutionScheduler _scheduler;
    private readonly CapturingAuditWriter _writer = new();
    private readonly IServiceProvider _services;

    public ScriptActorTraceTests()
    {
        _sharedLibrary = new SharedScriptLibrary(
            new ScriptCompilationService(NullLogger<ScriptCompilationService>.Instance),
            NullLogger<SharedScriptLibrary>.Instance);
        _options = new SiteRuntimeOptions { MaxScriptCallDepth = 10, ScriptExecutionTimeoutSeconds = 30 };
        _scheduler = new ScriptExecutionScheduler(_options.ScriptExecutionThreadCount);
        var sc = new ServiceCollection();
        sc.AddSingleton<IAuditWriter>(_writer);
        _services = sc.BuildServiceProvider();
    }

    void IDisposable.Dispose()
    {
        Shutdown();
        _scheduler.Dispose();
    }

    private static Script<object?> Compile(string code)
    {
        var script = CSharpScript.Create<object?>(code,
            ScriptOptions.Default.WithReferences(typeof(object).Assembly, typeof(Enumerable).Assembly)
                .WithImports("System", "System.Collections.Generic", "System.Linq", "System.Threading.Tasks"),
            typeof(ScriptGlobals));
        script.Compile();
        return script;
    }

    private IActorRef CreateActor(string name, string code, string? triggerJson = null)
    {
        var config = new ResolvedScript { CanonicalName = name, Code = code, TriggerType = triggerJson is null ? null : "valuechange", TriggerConfiguration = triggerJson };
        return ActorOf(Props.Create(() => new ScriptActor(
            name, "Pump1", CreateTestProbe().Ref, Compile(code), config, _sharedLibrary, _options,
            NullLogger<ScriptActor>.Instance, null, null, null, _services, _scheduler)));
    }

    [Fact]
    public void Call_WithTrace_ReplyCarriesExecutionId_AndAScriptRunEvent()
    {
        var actor = CreateActor("Add", "(int)Parameters[\"x\"] + 1");

        actor.Tell(new ScriptCallRequest("Add", new Dictionary<string, object?> { ["x"] = 41 }, 0, "cid", Trace: true));

        var result = ExpectMsg<ScriptCallResult>(TimeSpan.FromSeconds(10));
        Assert.True(result.Success, result.ErrorMessage);
        Assert.Equal(42, result.ReturnValue);
        Assert.NotNull(result.ExecutionId);
        var evt = Assert.Single(result.TraceEvents!);
        var row = evt.AsRow();
        Assert.Equal("ScriptTrace.ScriptRun", evt.Action);
        Assert.Equal("Delivered", row.Status.ToString());
        Assert.Equal(result.ExecutionId, row.ExecutionId);
        Assert.Equal("Add", evt.Target);
        Assert.Equal("Pump1", row.SourceInstanceId);
        Assert.Contains("\"x\":41", row.RequestSummary);
        Assert.Equal("42", row.ResponseSummary);
        Assert.Equal("call", ScriptTraceExtra.TryParse(row.Extra)!.TriggerKind);

        // The same row went through the audit writer.
        Assert.NotNull(_writer.WaitForKind("ScriptTrace.ScriptRun", TimeSpan.FromSeconds(5)));
    }

    [Fact]
    public void Call_WithTrace_FailedRun_ReturnsFailedScriptRunEvent()
    {
        var actor = CreateActor("Boom", "throw new InvalidOperationException(\"kaboom\");");

        actor.Tell(new ScriptCallRequest("Boom", null, 0, "cid", Trace: true));

        var result = ExpectMsg<ScriptCallResult>(TimeSpan.FromSeconds(10));
        Assert.False(result.Success);
        Assert.NotNull(result.ExecutionId);
        var row = Assert.Single(result.TraceEvents!).AsRow();
        Assert.Equal("Failed", row.Status.ToString());
        Assert.Contains("kaboom", row.ErrorMessage);
    }

    [Fact]
    public void Call_WithoutTrace_ReplyHasNoTraceEvents_ButStillCarriesExecutionId()
    {
        var actor = CreateActor("Answer", "42");

        actor.Tell(new ScriptCallRequest("Answer", null, 0, "cid"));

        var result = ExpectMsg<ScriptCallResult>(TimeSpan.FromSeconds(10));
        Assert.True(result.Success);
        Assert.NotNull(result.ExecutionId);
        Assert.Null(result.TraceEvents);
        Thread.Sleep(200);
        Assert.Empty(_writer.Events);
    }

    [Fact]
    public void ValueChangeTrigger_TracedChange_RunParentsToSourceExecutionId()
    {
        var actor = CreateActor("OnStatus", "1", "{\"attribute\":\"Status\"}");
        var writer = Guid.NewGuid();
        var now = DateTimeOffset.UtcNow;

        actor.Tell(new AttributeValueChanged("Pump1", "Status", "Status", "Running", "Good", now, SourceExecutionId: writer, Trace: true));

        var evt = _writer.WaitForKind("ScriptTrace.ScriptRun", TimeSpan.FromSeconds(10));
        Assert.NotNull(evt);
        var row = evt!.AsRow();
        Assert.Equal(writer, row.ParentExecutionId);
        Assert.NotEqual(writer, row.ExecutionId);
        var extra = ScriptTraceExtra.TryParse(row.Extra)!;
        Assert.Equal("valuechange", extra.TriggerKind);
        Assert.Equal("Status", extra.TriggerAttribute);
        Assert.Equal("Running", extra.TriggerValue);
        Assert.Equal("value-change", extra.TriggerSource);
    }

    [Fact]
    public void ValueChangeTrigger_UntracedChange_RunStaysRoot_AndEmitsNothing()
    {
        var actor = CreateActor("OnStatus", "1", "{\"attribute\":\"Status\"}");

        // Stamped but NOT traced (an ordinary script write) — and a plain DCL change.
        actor.Tell(new AttributeValueChanged("Pump1", "Status", "Status", "Running", "Good", DateTimeOffset.UtcNow, SourceExecutionId: Guid.NewGuid()));
        actor.Tell(new AttributeValueChanged("Pump1", "Status", "Status", "Stopped", "Good", DateTimeOffset.UtcNow));

        Assert.Null(_writer.WaitForKind("ScriptTrace.ScriptRun", TimeSpan.FromSeconds(1)));
        Assert.Empty(_writer.Events);
    }
}