using Akka.Actor;
using Akka.TestKit.Xunit2;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using NSubstitute;
using ScadaLink.Commons.Entities.Deployment;
using ScadaLink.Commons.Entities.Instances;
using ScadaLink.Commons.Interfaces.Repositories;
using ScadaLink.Commons.Interfaces.Services;
using ScadaLink.Commons.Messages.Deployment;
using ScadaLink.Commons.Messages.Lifecycle;
using ScadaLink.Commons.Types;
using ScadaLink.Commons.Types.Enums;
using ScadaLink.Commons.Types.Flattening;
using ScadaLink.Communication;
using ScadaLink.TemplateEngine.Flattening;

namespace ScadaLink.DeploymentManager.Tests;

/// <summary>
/// WP-1/2/4/5/6/8/16: Tests for central-side DeploymentService.
/// </summary>
public class DeploymentServiceTests : TestKit
{
    private readonly IDeploymentManagerRepository _repo;
    private readonly IFlatteningPipeline _pipeline;
    private readonly CommunicationService _comms;
    private readonly OperationLockManager _lockManager;
    private readonly IAuditService _audit;
    private readonly DeploymentService _service;

    public DeploymentServiceTests()
    {
        _repo = Substitute.For<IDeploymentManagerRepository>();
        _pipeline = Substitute.For<IFlatteningPipeline>();
        _comms = new CommunicationService(
            Options.Create(new CommunicationOptions()),
            NullLogger<CommunicationService>.Instance);
        _lockManager = new OperationLockManager();
        _audit = Substitute.For<IAuditService>();

        var options = Options.Create(new DeploymentManagerOptions
        {
            OperationLockTimeout = TimeSpan.FromSeconds(5)
        });

        var siteRepo = Substitute.For<ISiteRepository>();
        _service = new DeploymentService(
            _repo, siteRepo, _pipeline, _comms, _lockManager, _audit,
            new DiffService(),
            new DeploymentStatusNotifier(NullLogger<DeploymentStatusNotifier>.Instance),
            options,
            NullLogger<DeploymentService>.Instance);
    }

    // ── WP-1: Deployment flow ──

    [Fact]
    public async Task DeployInstanceAsync_InstanceNotFound_ReturnsFailure()
    {
        _repo.GetInstanceByIdAsync(1).Returns((Instance?)null);

        var result = await _service.DeployInstanceAsync(1, "admin");

        Assert.True(result.IsFailure);
        Assert.Contains("not found", result.Error);
    }

    [Fact]
    public async Task DeployInstanceAsync_ValidationFails_ReturnsFailure()
    {
        var instance = new Instance("TestInst") { Id = 1, SiteId = 1, State = InstanceState.NotDeployed };
        _repo.GetInstanceByIdAsync(1).Returns(instance);

        var validationResult = new ValidationResult
        {
            Errors = [ValidationEntry.Error(ValidationCategory.ScriptCompilation, "Compile error")]
        };
        _pipeline.FlattenAndValidateAsync(1, Arg.Any<CancellationToken>())
            .Returns(Result<FlatteningPipelineResult>.Success(
                new FlatteningPipelineResult(new FlattenedConfiguration(), "hash1", validationResult)));

        var result = await _service.DeployInstanceAsync(1, "admin");

        Assert.True(result.IsFailure);
        Assert.Contains("validation failed", result.Error);
    }

    [Fact]
    public async Task DeployInstanceAsync_FlatteningFails_ReturnsFailure()
    {
        var instance = new Instance("TestInst") { Id = 1, SiteId = 1, State = InstanceState.NotDeployed };
        _repo.GetInstanceByIdAsync(1).Returns(instance);

        _pipeline.FlattenAndValidateAsync(1, Arg.Any<CancellationToken>())
            .Returns(Result<FlatteningPipelineResult>.Failure("Template chain empty"));

        var result = await _service.DeployInstanceAsync(1, "admin");

        Assert.True(result.IsFailure);
        Assert.Contains("Validation failed", result.Error);
    }

    // ── WP-2: Deployment identity ──

    [Fact]
    public async Task DeployInstanceAsync_CreatesUniqueDeploymentId()
    {
        var instance = new Instance("TestInst") { Id = 1, SiteId = 1, State = InstanceState.NotDeployed };
        _repo.GetInstanceByIdAsync(1).Returns(instance);

        // Pipeline succeeds
        var config = new FlattenedConfiguration { InstanceUniqueName = "TestInst" };
        var validResult = ValidationResult.Success();
        _pipeline.FlattenAndValidateAsync(1, Arg.Any<CancellationToken>())
            .Returns(Result<FlatteningPipelineResult>.Success(
                new FlatteningPipelineResult(config, "sha256:abc", validResult)));

        // Capture the deployment record
        DeploymentRecord? captured = null;
        await _repo.AddDeploymentRecordAsync(Arg.Do<DeploymentRecord>(r => captured = r), Arg.Any<CancellationToken>());

        // CommunicationService will throw because actor not set -- this tests the flow up to that point
        try
        {
            await _service.DeployInstanceAsync(1, "admin");
        }
        catch (InvalidOperationException)
        {
            // Expected -- CommunicationService not initialized
        }

        Assert.NotNull(captured);
        Assert.False(string.IsNullOrEmpty(captured!.DeploymentId));
        Assert.Equal(32, captured.DeploymentId.Length); // GUID without hyphens
        Assert.Equal("sha256:abc", captured.RevisionHash);
    }

    // ── WP-4: State transition validation ──

    [Fact]
    public async Task DeployInstanceAsync_EnabledInstance_AllowsDeploy()
    {
        var instance = new Instance("TestInst") { Id = 1, SiteId = 1, State = InstanceState.Enabled };
        _repo.GetInstanceByIdAsync(1).Returns(instance);

        var config = new FlattenedConfiguration { InstanceUniqueName = "TestInst" };
        _pipeline.FlattenAndValidateAsync(1, Arg.Any<CancellationToken>())
            .Returns(Result<FlatteningPipelineResult>.Success(
                new FlatteningPipelineResult(config, "hash", ValidationResult.Success())));

        // Will fail at communication layer, but passes state validation
        try { await _service.DeployInstanceAsync(1, "admin"); } catch (InvalidOperationException) { }

        // If we got past state validation, the deployment record was created
        await _repo.Received().AddDeploymentRecordAsync(Arg.Any<DeploymentRecord>(), Arg.Any<CancellationToken>());
    }

    // ── DeploymentManager-001: unexpected exception must not leave record InProgress ──

    [Fact]
    public async Task DeployInstanceAsync_CommunicationThrowsUnexpectedException_RecordMarkedFailed()
    {
        var instance = new Instance("TestInst") { Id = 1, SiteId = 1, State = InstanceState.NotDeployed };
        _repo.GetInstanceByIdAsync(1).Returns(instance);

        var config = new FlattenedConfiguration { InstanceUniqueName = "TestInst" };
        _pipeline.FlattenAndValidateAsync(1, Arg.Any<CancellationToken>())
            .Returns(Result<FlatteningPipelineResult>.Success(
                new FlatteningPipelineResult(config, "sha256:abc", ValidationResult.Success())));

        // Capture the deployment record so we can inspect its final state.
        DeploymentRecord? captured = null;
        await _repo.AddDeploymentRecordAsync(
            Arg.Do<DeploymentRecord>(r => captured = r), Arg.Any<CancellationToken>());

        // _comms has no actor set, so DeployInstanceAsync throws
        // InvalidOperationException -- a non-timeout, non-cancellation exception.
        var result = await _service.DeployInstanceAsync(1, "admin");

        // The exception must be handled, not escape.
        Assert.True(result.IsFailure);
        Assert.Contains("Deployment failed", result.Error);

        // The record must not be left stuck in InProgress.
        Assert.NotNull(captured);
        Assert.Equal(DeploymentStatus.Failed, captured!.Status);
        Assert.NotNull(captured.ErrorMessage);
        Assert.NotNull(captured.CompletedAt);
    }

    // ── DeploymentManager-002: failure write must not use a cancelled token ──

    [Fact]
    public async Task DeployInstanceAsync_FailureWrite_UsesNonCancellableToken()
    {
        var instance = new Instance("TestInst") { Id = 1, SiteId = 1, State = InstanceState.NotDeployed };
        _repo.GetInstanceByIdAsync(Arg.Any<int>(), Arg.Any<CancellationToken>()).Returns(instance);

        var config = new FlattenedConfiguration { InstanceUniqueName = "TestInst" };
        _pipeline.FlattenAndValidateAsync(Arg.Any<int>(), Arg.Any<CancellationToken>())
            .Returns(Result<FlatteningPipelineResult>.Success(
                new FlatteningPipelineResult(config, "sha256:abc", ValidationResult.Success())));

        DeploymentRecord? captured = null;
        await _repo.AddDeploymentRecordAsync(
            Arg.Do<DeploymentRecord>(r => captured = r), Arg.Any<CancellationToken>());

        // Simulate a repository that rejects already-cancelled tokens (the
        // real EF Core behaviour when the operation token is cancelled). If the
        // catch block passes the operation's cancelled token, the Failed-status
        // write throws and the record stays InProgress -- the exact bug.
        _repo.UpdateDeploymentRecordAsync(
                Arg.Is<DeploymentRecord>(r => r.Status == DeploymentStatus.Failed),
                Arg.Is<CancellationToken>(ct => ct.IsCancellationRequested))
            .Returns<Task>(_ => throw new OperationCanceledException());
        _repo.SaveChangesAsync(Arg.Is<CancellationToken>(ct => ct.IsCancellationRequested))
            .Returns<Task<int>>(_ => throw new OperationCanceledException());

        // The communication call fails (no actor set). The catch block must
        // persist the Failed status with a non-cancellable token, so cleanup
        // succeeds even when the caller's token is cancelled.
        var result = await _service.DeployInstanceAsync(1, "admin");

        Assert.True(result.IsFailure);
        Assert.NotNull(captured);
        Assert.Equal(DeploymentStatus.Failed, captured!.Status);

        // The Failed-status write happened with a non-cancelled token.
        await _repo.Received().UpdateDeploymentRecordAsync(
            Arg.Is<DeploymentRecord>(r => r.Status == DeploymentStatus.Failed),
            Arg.Is<CancellationToken>(ct => !ct.IsCancellationRequested));
    }

    // ── WP-6: Lifecycle commands ──

    [Fact]
    public async Task DisableInstanceAsync_InstanceNotFound_ReturnsFailure()
    {
        _repo.GetInstanceByIdAsync(1).Returns((Instance?)null);

        var result = await _service.DisableInstanceAsync(1, "admin");

        Assert.True(result.IsFailure);
        Assert.Contains("not found", result.Error);
    }

    [Fact]
    public async Task DisableInstanceAsync_WhenDisabled_ReturnsTransitionError()
    {
        var instance = new Instance("TestInst") { Id = 1, SiteId = 1, State = InstanceState.Disabled };
        _repo.GetInstanceByIdAsync(1).Returns(instance);

        var result = await _service.DisableInstanceAsync(1, "admin");

        Assert.True(result.IsFailure);
        Assert.Contains("not allowed", result.Error);
    }

    [Fact]
    public async Task EnableInstanceAsync_WhenEnabled_ReturnsTransitionError()
    {
        var instance = new Instance("TestInst") { Id = 1, SiteId = 1, State = InstanceState.Enabled };
        _repo.GetInstanceByIdAsync(1).Returns(instance);

        var result = await _service.EnableInstanceAsync(1, "admin");

        Assert.True(result.IsFailure);
        Assert.Contains("not allowed", result.Error);
    }

    [Fact]
    public async Task DeleteInstanceAsync_InstanceNotFound_ReturnsFailure()
    {
        _repo.GetInstanceByIdAsync(1).Returns((Instance?)null);

        var result = await _service.DeleteInstanceAsync(1, "admin");

        Assert.True(result.IsFailure);
        Assert.Contains("not found", result.Error);
    }

    // ── DeploymentManager-004: site-success but central-delete-failure must not escape uncaught ──

    [Fact]
    public async Task DeleteInstanceAsync_SiteSucceeds_CentralDeleteFails_ReturnsDistinctFailure()
    {
        // The site destroys the Instance Actor and removes its config (response
        // Success), but the central record removal throws. The exception must
        // NOT propagate uncaught -- it must be surfaced as a distinct failure so
        // an operator can reconcile the orphaned central record.
        var instance = new Instance("OrphanInst") { Id = 30, SiteId = 1, State = InstanceState.Enabled };
        _repo.GetInstanceByIdAsync(30, Arg.Any<CancellationToken>()).Returns(instance);

        _repo.DeleteInstanceAsync(30, Arg.Any<CancellationToken>())
            .Returns<Task>(_ => throw new InvalidOperationException("db unavailable"));

        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "sha256:x", failQuery: false)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.DeleteInstanceAsync(30, "admin");

        // The failure is surfaced (not thrown) and clearly says the site
        // succeeded but the central record could not be removed.
        Assert.True(result.IsFailure);
        Assert.Contains("site", result.Error, StringComparison.OrdinalIgnoreCase);
        Assert.Contains("central", result.Error, StringComparison.OrdinalIgnoreCase);
    }

    // ── WP-8: Deployment comparison ──

    [Fact]
    public async Task GetDeploymentComparisonAsync_NoSnapshot_ReturnsFailure()
    {
        _repo.GetDeployedSnapshotByInstanceIdAsync(1).Returns((DeployedConfigSnapshot?)null);

        var result = await _service.GetDeploymentComparisonAsync(1);

        Assert.True(result.IsFailure);
        Assert.Contains("No deployed snapshot", result.Error);
    }

    [Fact]
    public async Task GetDeploymentComparisonAsync_SameHash_NotStale()
    {
        var snapshot = new DeployedConfigSnapshot("dep1", "sha256:abc", "{}")
        {
            InstanceId = 1,
            DeployedAt = DateTimeOffset.UtcNow
        };
        _repo.GetDeployedSnapshotByInstanceIdAsync(1).Returns(snapshot);

        var config = new FlattenedConfiguration { InstanceUniqueName = "TestInst" };
        _pipeline.FlattenAndValidateAsync(1, Arg.Any<CancellationToken>())
            .Returns(Result<FlatteningPipelineResult>.Success(
                new FlatteningPipelineResult(config, "sha256:abc", ValidationResult.Success())));

        var result = await _service.GetDeploymentComparisonAsync(1);

        Assert.True(result.IsSuccess);
        Assert.False(result.Value.IsStale);
    }

    [Fact]
    public async Task GetDeploymentComparisonAsync_DifferentHash_IsStale()
    {
        var snapshot = new DeployedConfigSnapshot("dep1", "sha256:abc", "{}")
        {
            InstanceId = 1,
            DeployedAt = DateTimeOffset.UtcNow
        };
        _repo.GetDeployedSnapshotByInstanceIdAsync(1).Returns(snapshot);

        var config = new FlattenedConfiguration { InstanceUniqueName = "TestInst" };
        _pipeline.FlattenAndValidateAsync(1, Arg.Any<CancellationToken>())
            .Returns(Result<FlatteningPipelineResult>.Success(
                new FlatteningPipelineResult(config, "sha256:xyz", ValidationResult.Success())));

        var result = await _service.GetDeploymentComparisonAsync(1);

        Assert.True(result.IsSuccess);
        Assert.True(result.Value.IsStale);
    }

    // ── DeploymentManager-007: comparison must produce a structured diff ──

    [Fact]
    public async Task GetDeploymentComparisonAsync_ProducesStructuredDiff()
    {
        // The deployed snapshot has one attribute; the current template-derived
        // config has a different attribute. The comparison must surface a real
        // Added/Removed diff via the TemplateEngine DiffService, not just a
        // boolean staleness flag.
        var deployedConfig = new FlattenedConfiguration
        {
            InstanceUniqueName = "DiffInst",
            Attributes = [new ResolvedAttribute { CanonicalName = "OldAttr", DataType = "Int" }]
        };
        var snapshot = new DeployedConfigSnapshot(
            "dep1", "sha256:old", System.Text.Json.JsonSerializer.Serialize(deployedConfig))
        {
            InstanceId = 40,
            DeployedAt = DateTimeOffset.UtcNow
        };
        _repo.GetDeployedSnapshotByInstanceIdAsync(40, Arg.Any<CancellationToken>()).Returns(snapshot);

        var currentConfig = new FlattenedConfiguration
        {
            InstanceUniqueName = "DiffInst",
            Attributes = [new ResolvedAttribute { CanonicalName = "NewAttr", DataType = "Int" }]
        };
        _pipeline.FlattenAndValidateAsync(40, Arg.Any<CancellationToken>())
            .Returns(Result<FlatteningPipelineResult>.Success(
                new FlatteningPipelineResult(currentConfig, "sha256:new", ValidationResult.Success())));

        var result = await _service.GetDeploymentComparisonAsync(40);

        Assert.True(result.IsSuccess);
        Assert.True(result.Value.IsStale);

        // A structured diff is present with the added and removed attributes.
        Assert.NotNull(result.Value.Diff);
        Assert.True(result.Value.Diff!.HasChanges);
        Assert.Contains(result.Value.Diff.AttributeChanges,
            c => c.CanonicalName == "NewAttr" && c.ChangeType == DiffChangeType.Added);
        Assert.Contains(result.Value.Diff.AttributeChanges,
            c => c.CanonicalName == "OldAttr" && c.ChangeType == DiffChangeType.Removed);
    }

    // ── WP-2: GetDeploymentStatusAsync ──

    [Fact]
    public async Task GetDeploymentStatusAsync_ReturnsRecordByDeploymentId()
    {
        var record = new DeploymentRecord("dep1", "admin")
        {
            Status = DeploymentStatus.Success
        };
        _repo.GetDeploymentByDeploymentIdAsync("dep1").Returns(record);

        var result = await _service.GetDeploymentStatusAsync("dep1");

        Assert.NotNull(result);
        Assert.Equal("dep1", result!.DeploymentId);
        Assert.Equal(DeploymentStatus.Success, result.Status);
    }

    // ── Audit logging ──

    [Fact]
    public async Task DeployInstanceAsync_FlatteningFails_DoesNotReachAudit()
    {
        // DeploymentManager-011: this test previously asserted nothing. A
        // flatten failure returns before any site communication, so no audit
        // entry is written.
        var instance = new Instance("TestInst") { Id = 1, SiteId = 1, State = InstanceState.NotDeployed };
        _repo.GetInstanceByIdAsync(1).Returns(instance);

        _pipeline.FlattenAndValidateAsync(1, Arg.Any<CancellationToken>())
            .Returns(Result<FlatteningPipelineResult>.Failure("Error"));

        await _service.DeployInstanceAsync(1, "admin");

        await _audit.DidNotReceive().LogAsync(
            Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>(),
            Arg.Any<string>(), Arg.Any<object>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task DeployInstanceAsync_SiteSucceeds_WritesDeployAuditEntry()
    {
        // DeploymentManager-011: a successful deployment must write a "Deploy"
        // audit entry referencing the deployed instance.
        var instance = new Instance("AuditInst") { Id = 50, SiteId = 1, State = InstanceState.NotDeployed };
        _repo.GetInstanceByIdAsync(50, Arg.Any<CancellationToken>()).Returns(instance);
        SetupValidPipeline(50, "AuditInst", "sha256:target");
        _repo.GetCurrentDeploymentStatusAsync(50, Arg.Any<CancellationToken>())
            .Returns((DeploymentRecord?)null);

        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "sha256:target", failQuery: false)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.DeployInstanceAsync(50, "admin");

        Assert.True(result.IsSuccess);
        await _audit.Received().LogAsync(
            "admin", "Deploy", "Instance", "50", "AuditInst",
            Arg.Any<object>(), Arg.Any<CancellationToken>());
    }

    // ── DeploymentManager-011: lifecycle success paths ──

    [Fact]
    public async Task DisableInstanceAsync_SiteSucceeds_SetsDisabledStateAndAudits()
    {
        var instance = new Instance("DisInst") { Id = 51, SiteId = 1, State = InstanceState.Enabled };
        _repo.GetInstanceByIdAsync(51, Arg.Any<CancellationToken>()).Returns(instance);

        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "x", failQuery: false)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.DisableInstanceAsync(51, "admin");

        Assert.True(result.IsSuccess);
        Assert.Equal(InstanceState.Disabled, instance.State);
        await _repo.Received().UpdateInstanceAsync(instance, Arg.Any<CancellationToken>());
        await _audit.Received().LogAsync(
            "admin", "Disable", "Instance", "51", "DisInst",
            Arg.Any<object>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task EnableInstanceAsync_SiteSucceeds_SetsEnabledStateAndAudits()
    {
        var instance = new Instance("EnInst") { Id = 52, SiteId = 1, State = InstanceState.Disabled };
        _repo.GetInstanceByIdAsync(52, Arg.Any<CancellationToken>()).Returns(instance);

        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "x", failQuery: false)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.EnableInstanceAsync(52, "admin");

        Assert.True(result.IsSuccess);
        Assert.Equal(InstanceState.Enabled, instance.State);
        await _repo.Received().UpdateInstanceAsync(instance, Arg.Any<CancellationToken>());
        await _audit.Received().LogAsync(
            "admin", "Enable", "Instance", "52", "EnInst",
            Arg.Any<object>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task DeleteInstanceAsync_SiteSucceeds_RemovesRecordAndAudits()
    {
        var instance = new Instance("DelInst") { Id = 53, SiteId = 1, State = InstanceState.Enabled };
        _repo.GetInstanceByIdAsync(53, Arg.Any<CancellationToken>()).Returns(instance);

        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "x", failQuery: false)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.DeleteInstanceAsync(53, "admin");

        Assert.True(result.IsSuccess);
        await _repo.Received().DeleteInstanceAsync(53, Arg.Any<CancellationToken>());
        await _audit.Received().LogAsync(
            "admin", "Delete", "Instance", "53", "DelInst",
            Arg.Any<object>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task DeployInstanceAsync_SameInstance_OperationLockSerializesConcurrentDeploys()
    {
        // DeploymentManager-011: two concurrent deploys of the SAME instance
        // must be serialized by the per-instance operation lock — the site sees
        // them one at a time, never overlapping.
        var instance = new Instance("LockInst") { Id = 54, SiteId = 1, State = InstanceState.Enabled };
        _repo.GetInstanceByIdAsync(54, Arg.Any<CancellationToken>()).Returns(instance);
        SetupValidPipeline(54, "LockInst", "sha256:target");
        _repo.GetCurrentDeploymentStatusAsync(54, Arg.Any<CancellationToken>())
            .Returns((DeploymentRecord?)null);

        var commActor = Sys.ActorOf(Props.Create(() =>
            new SerializationProbeActor()));
        var service = CreateServiceWithCommActor(commActor);

        var deploy1 = service.DeployInstanceAsync(54, "admin");
        var deploy2 = service.DeployInstanceAsync(54, "admin");
        var results = await Task.WhenAll(deploy1, deploy2);

        Assert.True(results[0].IsSuccess);
        Assert.True(results[1].IsSuccess);
        // The probe records the maximum concurrency observed; the lock must
        // keep it at 1 for a single instance.
        Assert.Equal(1, SerializationProbeActor.MaxConcurrent);
    }

    // ── DeploymentManager-006: query-the-site-before-redeploy idempotency ──

    /// <summary>
    /// Builds a DeploymentService whose CommunicationService is backed by the
    /// supplied actor, so the site query and deploy commands can be observed.
    /// </summary>
    private DeploymentService CreateServiceWithCommActor(IActorRef commActor)
    {
        var comms = new CommunicationService(
            Options.Create(new CommunicationOptions
            {
                QueryTimeout = TimeSpan.FromSeconds(5),
                DeploymentTimeout = TimeSpan.FromSeconds(5)
            }),
            NullLogger<CommunicationService>.Instance);
        comms.SetCommunicationActor(commActor);

        var siteRepo = Substitute.For<ISiteRepository>();
        return new DeploymentService(
            _repo, siteRepo, _pipeline, comms, _lockManager, _audit,
            new DiffService(),
            new DeploymentStatusNotifier(NullLogger<DeploymentStatusNotifier>.Instance),
            Options.Create(new DeploymentManagerOptions { OperationLockTimeout = TimeSpan.FromSeconds(5) }),
            NullLogger<DeploymentService>.Instance);
    }

    private void SetupValidPipeline(int instanceId, string instanceName, string revisionHash)
    {
        var config = new FlattenedConfiguration { InstanceUniqueName = instanceName };
        _pipeline.FlattenAndValidateAsync(instanceId, Arg.Any<CancellationToken>())
            .Returns(Result<FlatteningPipelineResult>.Success(
                new FlatteningPipelineResult(config, revisionHash, ValidationResult.Success())));
    }

    [Fact]
    public async Task DeployInstanceAsync_PriorInProgressRecord_SiteHasTargetHash_MarksSuccessWithoutRedeploy()
    {
        // Prior record stuck InProgress -> site is queried. The site reports it
        // already has the TARGET revision hash, so the prior record is marked
        // Success and NO new DeployInstanceCommand is sent.
        var instance = new Instance("RedeployInst") { Id = 7, SiteId = 1, State = InstanceState.Enabled };
        _repo.GetInstanceByIdAsync(7, Arg.Any<CancellationToken>()).Returns(instance);
        SetupValidPipeline(7, "RedeployInst", "sha256:target");

        var prior = new DeploymentRecord("dep-prior", "admin")
        {
            InstanceId = 7,
            Status = DeploymentStatus.InProgress,
            RevisionHash = "sha256:target"
        };
        _repo.GetCurrentDeploymentStatusAsync(7, Arg.Any<CancellationToken>()).Returns(prior);

        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "sha256:target", failQuery: false)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.DeployInstanceAsync(7, "admin");

        Assert.True(result.IsSuccess);
        Assert.Equal(DeploymentStatus.Success, prior.Status);
        // The site query was issued, but no new deploy command was sent.
        Assert.Equal(1, ReconcileProbeActor.QueryCount);
        Assert.Equal(0, ReconcileProbeActor.DeployCount);
        // No new deployment record was created — the prior one was reconciled.
        await _repo.DidNotReceive().AddDeploymentRecordAsync(
            Arg.Any<DeploymentRecord>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task DeployInstanceAsync_PriorInProgressRecord_SiteHasDifferentHash_ProceedsWithDeploy()
    {
        // Prior record stuck InProgress -> site is queried. The site has a
        // DIFFERENT revision hash, so the normal deploy proceeds.
        var instance = new Instance("RedeployInst2") { Id = 8, SiteId = 1, State = InstanceState.Enabled };
        _repo.GetInstanceByIdAsync(8, Arg.Any<CancellationToken>()).Returns(instance);
        SetupValidPipeline(8, "RedeployInst2", "sha256:target");

        var prior = new DeploymentRecord("dep-prior2", "admin")
        {
            InstanceId = 8,
            Status = DeploymentStatus.InProgress,
            RevisionHash = "sha256:old"
        };
        _repo.GetCurrentDeploymentStatusAsync(8, Arg.Any<CancellationToken>()).Returns(prior);

        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "sha256:old", failQuery: false)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.DeployInstanceAsync(8, "admin");

        Assert.True(result.IsSuccess);
        Assert.Equal(1, ReconcileProbeActor.QueryCount);
        // The normal deploy proceeded — a new command was sent.
        Assert.Equal(1, ReconcileProbeActor.DeployCount);
        await _repo.Received().AddDeploymentRecordAsync(
            Arg.Any<DeploymentRecord>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public async Task DeployInstanceAsync_PriorFailedTimeoutRecord_QueriesSite()
    {
        // A prior record Failed due to a timeout also triggers the site query.
        var instance = new Instance("TimedOutInst") { Id = 9, SiteId = 1, State = InstanceState.Enabled };
        _repo.GetInstanceByIdAsync(9, Arg.Any<CancellationToken>()).Returns(instance);
        SetupValidPipeline(9, "TimedOutInst", "sha256:target");

        var prior = new DeploymentRecord("dep-prior3", "admin")
        {
            InstanceId = 9,
            Status = DeploymentStatus.Failed,
            RevisionHash = "sha256:target",
            ErrorMessage = "Communication failure: deployment Ask timed out"
        };
        _repo.GetCurrentDeploymentStatusAsync(9, Arg.Any<CancellationToken>()).Returns(prior);

        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "sha256:target", failQuery: false)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.DeployInstanceAsync(9, "admin");

        Assert.True(result.IsSuccess);
        Assert.Equal(1, ReconcileProbeActor.QueryCount);
        Assert.Equal(0, ReconcileProbeActor.DeployCount);
        Assert.Equal(DeploymentStatus.Success, prior.Status);
    }

    [Fact]
    public async Task DeployInstanceAsync_PriorSuccessRecord_SkipsSiteQuery()
    {
        // A clean prior Success record must NOT trigger the extra round-trip.
        var instance = new Instance("CleanInst") { Id = 10, SiteId = 1, State = InstanceState.Enabled };
        _repo.GetInstanceByIdAsync(10, Arg.Any<CancellationToken>()).Returns(instance);
        SetupValidPipeline(10, "CleanInst", "sha256:target");

        var prior = new DeploymentRecord("dep-clean", "admin")
        {
            InstanceId = 10,
            Status = DeploymentStatus.Success,
            RevisionHash = "sha256:old"
        };
        _repo.GetCurrentDeploymentStatusAsync(10, Arg.Any<CancellationToken>()).Returns(prior);

        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "sha256:target", failQuery: false)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.DeployInstanceAsync(10, "admin");

        Assert.True(result.IsSuccess);
        // No site query — the prior deploy completed cleanly.
        Assert.Equal(0, ReconcileProbeActor.QueryCount);
        Assert.Equal(1, ReconcileProbeActor.DeployCount);
    }

    [Fact]
    public async Task DeployInstanceAsync_FreshFirstTimeDeploy_SkipsSiteQuery()
    {
        // No prior record at all -> fresh deploy, no extra round-trip.
        var instance = new Instance("FreshInst") { Id = 11, SiteId = 1, State = InstanceState.NotDeployed };
        _repo.GetInstanceByIdAsync(11, Arg.Any<CancellationToken>()).Returns(instance);
        SetupValidPipeline(11, "FreshInst", "sha256:target");
        _repo.GetCurrentDeploymentStatusAsync(11, Arg.Any<CancellationToken>())
            .Returns((DeploymentRecord?)null);

        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "sha256:target", failQuery: false)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.DeployInstanceAsync(11, "admin");

        Assert.True(result.IsSuccess);
        Assert.Equal(0, ReconcileProbeActor.QueryCount);
        Assert.Equal(1, ReconcileProbeActor.DeployCount);
    }

    [Fact]
    public async Task DeployInstanceAsync_PriorInProgressRecord_QueryFails_FallsThroughToDeploy()
    {
        // The site query fails (unreachable / times out). The deploy must NOT
        // abort — it falls through to a normal deploy and relies on site-side
        // stale-rejection as the safety net.
        var instance = new Instance("UnreachableInst") { Id = 12, SiteId = 1, State = InstanceState.Enabled };
        _repo.GetInstanceByIdAsync(12, Arg.Any<CancellationToken>()).Returns(instance);
        SetupValidPipeline(12, "UnreachableInst", "sha256:target");

        var prior = new DeploymentRecord("dep-prior5", "admin")
        {
            InstanceId = 12,
            Status = DeploymentStatus.InProgress,
            RevisionHash = "sha256:target"
        };
        _repo.GetCurrentDeploymentStatusAsync(12, Arg.Any<CancellationToken>()).Returns(prior);

        // The probe drops the query (no reply) -> the Ask times out.
        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "sha256:target", failQuery: true)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.DeployInstanceAsync(12, "admin");

        // Did not abort — the deploy proceeded after the failed query.
        Assert.True(result.IsSuccess);
        Assert.Equal(1, ReconcileProbeActor.QueryCount);
        Assert.Equal(1, ReconcileProbeActor.DeployCount);
    }

    // ── DeploymentManager-015: reconciliation must perform the normal success side effects ──

    [Fact]
    public async Task DeployInstanceAsync_Reconciled_SetsInstanceEnabledAndStoresSnapshot()
    {
        // A prior deploy timed out; the site actually applied the target
        // revision. Reconciliation marks the prior record Success WITHOUT
        // re-sending -- but it must still perform the same side effects as the
        // normal success path: set the instance State to Enabled and store the
        // deployed-config snapshot. Otherwise central and site diverge.
        var instance = new Instance("ReconcileSideEffects")
        {
            Id = 70, SiteId = 1, State = InstanceState.NotDeployed
        };
        _repo.GetInstanceByIdAsync(70, Arg.Any<CancellationToken>()).Returns(instance);
        SetupValidPipeline(70, "ReconcileSideEffects", "sha256:target");

        var prior = new DeploymentRecord("dep-prior-70", "admin")
        {
            InstanceId = 70,
            Status = DeploymentStatus.InProgress,
            RevisionHash = "sha256:target"
        };
        _repo.GetCurrentDeploymentStatusAsync(70, Arg.Any<CancellationToken>()).Returns(prior);
        _repo.GetDeployedSnapshotByInstanceIdAsync(70, Arg.Any<CancellationToken>())
            .Returns((DeployedConfigSnapshot?)null);

        DeployedConfigSnapshot? storedSnapshot = null;
        await _repo.AddDeployedSnapshotAsync(
            Arg.Do<DeployedConfigSnapshot>(s => storedSnapshot = s), Arg.Any<CancellationToken>());

        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "sha256:target", failQuery: false)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.DeployInstanceAsync(70, "admin");

        Assert.True(result.IsSuccess);
        // No re-deploy was sent -- this was reconciled.
        Assert.Equal(1, ReconcileProbeActor.QueryCount);
        Assert.Equal(0, ReconcileProbeActor.DeployCount);

        // DeploymentManager-015: the instance State must reflect the deployed
        // config the site is actually running.
        Assert.Equal(InstanceState.Enabled, instance.State);
        await _repo.Received().UpdateInstanceAsync(instance, Arg.Any<CancellationToken>());

        // DeploymentManager-015: a deployed-config snapshot must be stored so
        // GetDeploymentComparisonAsync has something to compare against.
        Assert.NotNull(storedSnapshot);
        Assert.Equal(70, storedSnapshot!.InstanceId);
        Assert.Equal("sha256:target", storedSnapshot.RevisionHash);
    }

    // ── DeploymentManager-016: reconciled record must carry the target revision hash ──

    [Fact]
    public async Task DeployInstanceAsync_Reconciled_PriorRecordRevisionHashUpdatedToTarget()
    {
        // The prior record carries a stale revision hash (R1), but the site
        // reports it has the freshly-flattened target revision (R2). After
        // reconciliation the prior record's RevisionHash must agree with the
        // site's applied revision -- not keep the stale R1.
        var instance = new Instance("ReconcileStaleHash")
        {
            Id = 71, SiteId = 1, State = InstanceState.Enabled
        };
        _repo.GetInstanceByIdAsync(71, Arg.Any<CancellationToken>()).Returns(instance);
        SetupValidPipeline(71, "ReconcileStaleHash", "sha256:target");

        var prior = new DeploymentRecord("dep-prior-71", "admin")
        {
            InstanceId = 71,
            Status = DeploymentStatus.InProgress,
            RevisionHash = "sha256:stale-R1"
        };
        _repo.GetCurrentDeploymentStatusAsync(71, Arg.Any<CancellationToken>()).Returns(prior);
        _repo.GetDeployedSnapshotByInstanceIdAsync(71, Arg.Any<CancellationToken>())
            .Returns((DeployedConfigSnapshot?)null);

        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "sha256:target", failQuery: false)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.DeployInstanceAsync(71, "admin");

        Assert.True(result.IsSuccess);
        Assert.Equal(DeploymentStatus.Success, prior.Status);
        // DeploymentManager-016: the persisted record's RevisionHash must agree
        // with the site's applied revision, not keep the stale R1.
        Assert.Equal("sha256:target", prior.RevisionHash);
    }

    // ── DeploymentManager-012: LifecycleCommandTimeout must actually bound lifecycle commands ──

    [Fact]
    public async Task DisableInstanceAsync_SiteUnresponsive_LifecycleCommandTimeoutBoundsTheWait()
    {
        // The site never replies to the DisableInstanceCommand. A short
        // LifecycleCommandTimeout must abort the wait quickly -- if the option
        // is dead code the call would instead hang until CommunicationOptions
        // .LifecycleTimeout (much longer) elapses.
        var instance = new Instance("StuckInst") { Id = 60, SiteId = 1, State = InstanceState.Enabled };
        _repo.GetInstanceByIdAsync(60, Arg.Any<CancellationToken>()).Returns(instance);

        // Probe drops every message -> no reply ever arrives.
        var commActor = Sys.ActorOf(Props.Create(() => new SilentProbeActor()));

        var comms = new CommunicationService(
            Options.Create(new CommunicationOptions
            {
                // Long communication-layer timeout: if LifecycleCommandTimeout
                // were dead, the test would wait this long.
                LifecycleTimeout = TimeSpan.FromSeconds(30)
            }),
            NullLogger<CommunicationService>.Instance);
        comms.SetCommunicationActor(commActor);

        var siteRepo = Substitute.For<ISiteRepository>();
        var service = new DeploymentService(
            _repo, siteRepo, _pipeline, comms, _lockManager, _audit,
            new DiffService(),
            new DeploymentStatusNotifier(NullLogger<DeploymentStatusNotifier>.Instance),
            Options.Create(new DeploymentManagerOptions
            {
                OperationLockTimeout = TimeSpan.FromSeconds(5),
                LifecycleCommandTimeout = TimeSpan.FromMilliseconds(300)
            }),
            NullLogger<DeploymentService>.Instance);

        var sw = System.Diagnostics.Stopwatch.StartNew();
        var result = await service.DisableInstanceAsync(60, "admin");
        sw.Stop();

        Assert.True(result.IsFailure);
        // The 300ms LifecycleCommandTimeout bounded the wait well under the
        // 30s communication-layer timeout.
        Assert.True(sw.Elapsed < TimeSpan.FromSeconds(10),
            $"Lifecycle command was not bounded by LifecycleCommandTimeout (took {sw.Elapsed}).");
    }

    /// <summary>Stand-in actor that never replies to anything.</summary>
    private class SilentProbeActor : ReceiveActor
    {
        public SilentProbeActor() => ReceiveAny(_ => { });
    }

    // ── DeploymentManager-003: post-success persistence must commit the Success status ──

    [Fact]
    public async Task DeployInstanceAsync_SiteSucceeds_SnapshotWriteFails_RecordStillCommittedSuccess()
    {
        // The site applies the deployment (response Success), but storing the
        // deployed-config snapshot afterwards throws. The deployment record's
        // Success status MUST still be durably committed -- otherwise central
        // and site diverge: the site runs the new config while central shows a
        // non-Success record forever.
        var instance = new Instance("SnapFailInst") { Id = 20, SiteId = 1, State = InstanceState.NotDeployed };
        _repo.GetInstanceByIdAsync(20, Arg.Any<CancellationToken>()).Returns(instance);
        SetupValidPipeline(20, "SnapFailInst", "sha256:target");
        _repo.GetCurrentDeploymentStatusAsync(20, Arg.Any<CancellationToken>())
            .Returns((DeploymentRecord?)null);

        DeploymentRecord? captured = null;
        await _repo.AddDeploymentRecordAsync(
            Arg.Do<DeploymentRecord>(r => captured = r), Arg.Any<CancellationToken>());

        // The snapshot store throws.
        _repo.GetDeployedSnapshotByInstanceIdAsync(20, Arg.Any<CancellationToken>())
            .Returns((DeployedConfigSnapshot?)null);
        _repo.AddDeployedSnapshotAsync(Arg.Any<DeployedConfigSnapshot>(), Arg.Any<CancellationToken>())
            .Returns<Task>(_ => throw new InvalidOperationException("snapshot store unavailable"));

        var commActor = Sys.ActorOf(Props.Create(() =>
            new ReconcileProbeActor(siteHash: "sha256:target", failQuery: false)));
        var service = CreateServiceWithCommActor(commActor);

        var result = await service.DeployInstanceAsync(20, "admin");

        // The site succeeded -> the deployment is reported successful.
        Assert.True(result.IsSuccess);
        Assert.NotNull(captured);
        Assert.Equal(DeploymentStatus.Success, captured!.Status);

        // The Success status was committed (a SaveChanges happened with the
        // record in Success state) BEFORE the snapshot write was attempted.
        await _repo.Received().UpdateDeploymentRecordAsync(
            Arg.Is<DeploymentRecord>(r => r.Status == DeploymentStatus.Success),
            Arg.Any<CancellationToken>());
    }

    /// <summary>
    /// Stand-in CentralCommunicationActor that measures deploy concurrency. It
    /// defers each deploy reply via the scheduler, so if two deploys for the
    /// same instance were NOT serialized by the operation lock their windows
    /// would overlap and <see cref="MaxConcurrent"/> would exceed 1.
    /// </summary>
    private class SerializationProbeActor : ReceiveActor, IWithTimers
    {
        public static int MaxConcurrent;
        private static int _current;
        private static readonly object Gate = new();

        public ITimerScheduler Timers { get; set; } = null!;

        public SerializationProbeActor()
        {
            MaxConcurrent = 0;
            _current = 0;

            Receive<SiteEnvelope>(env =>
            {
                if (env.Message is DeployInstanceCommand d)
                {
                    lock (Gate)
                    {
                        _current++;
                        if (_current > MaxConcurrent) MaxConcurrent = _current;
                    }

                    var replyTo = Sender;
                    // Defer the reply so the deploy "window" stays open long
                    // enough for a non-serialized second deploy to overlap.
                    Timers.StartSingleTimer(
                        d.DeploymentId,
                        new CompleteDeploy(d, replyTo),
                        TimeSpan.FromMilliseconds(150));
                }
                else if (env.Message is DeploymentStateQueryRequest q)
                {
                    Sender.Tell(new DeploymentStateQueryResponse(
                        q.CorrelationId, q.InstanceUniqueName, false, null, null, DateTimeOffset.UtcNow));
                }
            });

            Receive<CompleteDeploy>(c =>
            {
                lock (Gate)
                {
                    _current--;
                }
                c.ReplyTo.Tell(new DeploymentStatusResponse(
                    c.Command.DeploymentId, c.Command.InstanceUniqueName,
                    DeploymentStatus.Success, null, DateTimeOffset.UtcNow));
            });
        }

        private sealed record CompleteDeploy(DeployInstanceCommand Command, IActorRef ReplyTo);
    }

    /// <summary>
    /// Stand-in CentralCommunicationActor for reconciliation tests. Counts the
    /// site queries and deploy commands it receives, answers queries with a
    /// configurable applied revision hash, and (optionally) drops the query to
    /// simulate an unreachable site so the central Ask times out.
    /// </summary>
    private class ReconcileProbeActor : ReceiveActor
    {
        public static int QueryCount;
        public static int DeployCount;

        public ReconcileProbeActor(string siteHash, bool failQuery)
        {
            // Each test creates a fresh actor; reset the shared counters.
            QueryCount = 0;
            DeployCount = 0;

            Receive<SiteEnvelope>(env =>
            {
                switch (env.Message)
                {
                    case DeploymentStateQueryRequest q:
                        QueryCount++;
                        if (!failQuery)
                        {
                            Sender.Tell(new DeploymentStateQueryResponse(
                                q.CorrelationId, q.InstanceUniqueName, true,
                                "dep-applied", siteHash, DateTimeOffset.UtcNow));
                        }
                        // failQuery: drop the message -> caller's Ask times out.
                        break;

                    case DeployInstanceCommand d:
                        DeployCount++;
                        Sender.Tell(new DeploymentStatusResponse(
                            d.DeploymentId, d.InstanceUniqueName,
                            DeploymentStatus.Success, null, DateTimeOffset.UtcNow));
                        break;

                    case DisableInstanceCommand dis:
                        Sender.Tell(new InstanceLifecycleResponse(
                            dis.CommandId, dis.InstanceUniqueName, true, null, DateTimeOffset.UtcNow));
                        break;

                    case EnableInstanceCommand en:
                        Sender.Tell(new InstanceLifecycleResponse(
                            en.CommandId, en.InstanceUniqueName, true, null, DateTimeOffset.UtcNow));
                        break;

                    case DeleteInstanceCommand del:
                        Sender.Tell(new InstanceLifecycleResponse(
                            del.CommandId, del.InstanceUniqueName, true, null, DateTimeOffset.UtcNow));
                        break;
                }
            });
        }
    }
}