using Akka.Actor;
using Akka.TestKit.Xunit2;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging.Abstractions;
using NSubstitute;
using ScadaLink.Commons.Entities.Audit;
using ScadaLink.Commons.Entities.Notifications;
using ScadaLink.Commons.Interfaces.Repositories;
using ScadaLink.Commons.Interfaces.Services;
using ScadaLink.Commons.Messages.Notification;
using ScadaLink.Commons.Types.Enums;
using ScadaLink.NotificationOutbox.Delivery;
using ScadaLink.NotificationOutbox.Messages;

namespace ScadaLink.NotificationOutbox.Tests;

/// <summary>
/// M4 Bundle B (B3) — verifies the <see cref="NotificationOutboxActor"/>
/// emits a second
/// <see cref="AuditChannel.Notification"/>/<see cref="AuditKind.NotifyDeliver"/>
/// audit row carrying the terminal status (Delivered, Parked, Discarded) on
/// every terminal-state transition. The B2 Attempted row is still emitted
/// alongside the terminal one — these tests assert ONLY the terminal row
/// presence and status.
/// </summary>
public class NotificationOutboxActorTerminalEmissionTests : TestKit
{
    private readonly INotificationOutboxRepository _outboxRepository =
        Substitute.For<INotificationOutboxRepository>();

    private readonly INotificationRepository _notificationRepository =
        Substitute.For<INotificationRepository>();

    private readonly RecordingCentralAuditWriter _auditWriter = new();

    private sealed class RecordingCentralAuditWriter : ICentralAuditWriter
    {
        public List<AuditEvent> Events { get; } = new();
        public Func<AuditEvent, Task>? OnWrite { get; set; }

        public Task WriteAsync(AuditEvent evt, CancellationToken ct = default)
        {
            lock (Events)
            {
                Events.Add(evt);
            }

            return OnWrite?.Invoke(evt) ?? Task.CompletedTask;
        }
    }

    private IServiceProvider BuildServiceProvider(IEnumerable<INotificationDeliveryAdapter> adapters)
    {
        var services = new ServiceCollection();
        services.AddScoped(_ => _outboxRepository);
        services.AddScoped(_ => _notificationRepository);
        foreach (var adapter in adapters)
        {
            services.AddScoped<INotificationDeliveryAdapter>(_ => adapter);
        }

        return services.BuildServiceProvider();
    }

    private sealed class StubAdapter : INotificationDeliveryAdapter
    {
        private readonly Func<DeliveryOutcome> _outcome;

        public StubAdapter(Func<DeliveryOutcome> outcome) { _outcome = outcome; }

        public NotificationType Type => NotificationType.Email;

        public Task<DeliveryOutcome> DeliverAsync(
            Notification notification, CancellationToken cancellationToken = default)
            => Task.FromResult(_outcome());
    }

    private IActorRef CreateActor(IEnumerable<INotificationDeliveryAdapter> adapters)
    {
        return Sys.ActorOf(Props.Create(() => new NotificationOutboxActor(
            BuildServiceProvider(adapters),
            new NotificationOutboxOptions { DispatchInterval = TimeSpan.FromHours(1) },
            (ICentralAuditWriter)_auditWriter,
            NullLogger<NotificationOutboxActor>.Instance)));
    }

    private static Notification MakeNotification(
        NotificationStatus status = NotificationStatus.Pending,
        int retryCount = 0,
        Guid? notificationId = null,
        Guid? originExecutionId = null)
    {
        return new Notification(
            (notificationId ?? Guid.NewGuid()).ToString("D"),
            NotificationType.Email,
            "ops-team",
            "Tank overflow",
            "Tank 3 level critical",
            "site-1")
        {
            Status = status,
            RetryCount = retryCount,
            CreatedAt = DateTimeOffset.UtcNow,
            OriginExecutionId = originExecutionId,
        };
    }

    private void SetupSmtpRetryPolicy(int maxRetries, TimeSpan retryDelay)
    {
        var config = new SmtpConfiguration("smtp.example.com", "Basic", "noreply@example.com")
        {
            MaxRetries = maxRetries,
            RetryDelay = retryDelay,
        };
        _notificationRepository.GetAllSmtpConfigurationsAsync(Arg.Any<CancellationToken>())
            .Returns(new[] { config });
    }

    private List<AuditEvent> EventsByStatus(AuditStatus status)
    {
        lock (_auditWriter.Events)
        {
            return _auditWriter.Events.Where(e => e.Status == status).ToList();
        }
    }

    [Fact]
    public void Terminal_Delivered_EmitsEvent_StatusDelivered()
    {
        SetupSmtpRetryPolicy(maxRetries: 5, retryDelay: TimeSpan.FromMinutes(1));
        var notification = MakeNotification();
        _outboxRepository.GetDueAsync(Arg.Any<DateTimeOffset>(), Arg.Any<int>(), Arg.Any<CancellationToken>())
            .Returns(new[] { notification });
        var adapter = new StubAdapter(() => DeliveryOutcome.Success("ops@example.com"));
        var actor = CreateActor([adapter]);

        actor.Tell(InternalMessages.DispatchTick.Instance);

        AwaitAssert(() =>
        {
            var delivered = EventsByStatus(AuditStatus.Delivered);
            Assert.Single(delivered);
            var evt = delivered[0];
            Assert.Equal(AuditChannel.Notification, evt.Channel);
            Assert.Equal(AuditKind.NotifyDeliver, evt.Kind);
            Assert.Equal("ops-team", evt.Target);
        });
    }

    [Fact]
    public void Terminal_Delivered_CarriesOriginExecutionId_AsExecutionId()
    {
        // Audit Log #23: the terminal NotifyDeliver row must echo the
        // notification's OriginExecutionId so it shares the per-run id with
        // the site-emitted NotifySend row.
        SetupSmtpRetryPolicy(maxRetries: 5, retryDelay: TimeSpan.FromMinutes(1));
        var executionId = Guid.NewGuid();
        var notification = MakeNotification(originExecutionId: executionId);
        _outboxRepository.GetDueAsync(Arg.Any<DateTimeOffset>(), Arg.Any<int>(), Arg.Any<CancellationToken>())
            .Returns(new[] { notification });
        var adapter = new StubAdapter(() => DeliveryOutcome.Success("ops@example.com"));
        var actor = CreateActor([adapter]);

        actor.Tell(InternalMessages.DispatchTick.Instance);

        AwaitAssert(() =>
        {
            var delivered = EventsByStatus(AuditStatus.Delivered);
            Assert.Single(delivered);
            Assert.Equal(executionId, delivered[0].ExecutionId);
        });
    }

    [Fact]
    public void Terminal_Delivered_NullOriginExecutionId_HasNullExecutionId()
    {
        SetupSmtpRetryPolicy(maxRetries: 5, retryDelay: TimeSpan.FromMinutes(1));
        var notification = MakeNotification(originExecutionId: null);
        _outboxRepository.GetDueAsync(Arg.Any<DateTimeOffset>(), Arg.Any<int>(), Arg.Any<CancellationToken>())
            .Returns(new[] { notification });
        var adapter = new StubAdapter(() => DeliveryOutcome.Success("ops@example.com"));
        var actor = CreateActor([adapter]);

        actor.Tell(InternalMessages.DispatchTick.Instance);

        AwaitAssert(() =>
        {
            var delivered = EventsByStatus(AuditStatus.Delivered);
            Assert.Single(delivered);
            Assert.Null(delivered[0].ExecutionId);
        });
    }

    [Fact]
    public void Terminal_Parked_OnPermanentFailure_EmitsEvent_StatusParked()
    {
        SetupSmtpRetryPolicy(maxRetries: 5, retryDelay: TimeSpan.FromMinutes(1));
        var notification = MakeNotification();
        _outboxRepository.GetDueAsync(Arg.Any<DateTimeOffset>(), Arg.Any<int>(), Arg.Any<CancellationToken>())
            .Returns(new[] { notification });
        var adapter = new StubAdapter(() => DeliveryOutcome.Permanent("invalid recipient address"));
        var actor = CreateActor([adapter]);

        actor.Tell(InternalMessages.DispatchTick.Instance);

        AwaitAssert(() =>
        {
            var parked = EventsByStatus(AuditStatus.Parked);
            Assert.Single(parked);
            Assert.Equal(AuditKind.NotifyDeliver, parked[0].Kind);
            Assert.Equal("invalid recipient address", parked[0].ErrorMessage);
        });
    }

    [Fact]
    public void Terminal_Parked_OnTransientReachingMaxRetries_EmitsEvent_StatusParked()
    {
        SetupSmtpRetryPolicy(maxRetries: 3, retryDelay: TimeSpan.FromMinutes(1));
        // RetryCount starts at max-1; the failed attempt increments it to max
        // which triggers the Parked terminal transition.
        var notification = MakeNotification(retryCount: 2);
        _outboxRepository.GetDueAsync(Arg.Any<DateTimeOffset>(), Arg.Any<int>(), Arg.Any<CancellationToken>())
            .Returns(new[] { notification });
        var adapter = new StubAdapter(() => DeliveryOutcome.Transient("smtp timeout"));
        var actor = CreateActor([adapter]);

        actor.Tell(InternalMessages.DispatchTick.Instance);

        AwaitAssert(() =>
        {
            var parked = EventsByStatus(AuditStatus.Parked);
            Assert.Single(parked);
            Assert.Equal(AuditKind.NotifyDeliver, parked[0].Kind);
        });
    }

    [Fact]
    public void Terminal_Parked_OnMissingAdapter_EmitsEvent_StatusParked()
    {
        SetupSmtpRetryPolicy(maxRetries: 5, retryDelay: TimeSpan.FromMinutes(1));
        var notification = MakeNotification();
        _outboxRepository.GetDueAsync(Arg.Any<DateTimeOffset>(), Arg.Any<int>(), Arg.Any<CancellationToken>())
            .Returns(new[] { notification });
        // No adapters registered: the missing-adapter park path runs.
        var actor = CreateActor([]);

        actor.Tell(InternalMessages.DispatchTick.Instance);

        AwaitAssert(() =>
        {
            var parked = EventsByStatus(AuditStatus.Parked);
            Assert.Single(parked);
            Assert.Equal(AuditKind.NotifyDeliver, parked[0].Kind);
            Assert.Contains("no delivery adapter", parked[0].ErrorMessage!);
        });
    }

    [Fact]
    public void Transient_BelowMaxRetries_DoesNotEmitTerminalRow()
    {
        // A transient failure that does not reach max-retries leaves the row
        // in Retrying — non-terminal, so no terminal audit row should be
        // emitted (only the Attempted row from B2).
        SetupSmtpRetryPolicy(maxRetries: 5, retryDelay: TimeSpan.FromMinutes(1));
        var notification = MakeNotification(retryCount: 0);
        _outboxRepository.GetDueAsync(Arg.Any<DateTimeOffset>(), Arg.Any<int>(), Arg.Any<CancellationToken>())
            .Returns(new[] { notification });
        var adapter = new StubAdapter(() => DeliveryOutcome.Transient("smtp timeout"));
        var actor = CreateActor([adapter]);

        actor.Tell(InternalMessages.DispatchTick.Instance);

        // Wait for the Attempted row to land so we know dispatch has run.
        AwaitAssert(() => Assert.Single(EventsByStatus(AuditStatus.Attempted)));

        // No terminal rows of any kind.
        Assert.Empty(EventsByStatus(AuditStatus.Delivered));
        Assert.Empty(EventsByStatus(AuditStatus.Parked));
        Assert.Empty(EventsByStatus(AuditStatus.Discarded));
    }

    [Fact]
    public void Terminal_Discarded_OnManualDiscard_EmitsEvent_StatusDiscarded()
    {
        // Wire the actor with a parked row that GetByIdAsync returns; the
        // discard handler must emit a terminal Discarded audit row.
        SetupSmtpRetryPolicy(maxRetries: 5, retryDelay: TimeSpan.FromMinutes(1));
        var notification = MakeNotification(status: NotificationStatus.Parked);
        _outboxRepository.GetByIdAsync(notification.NotificationId, Arg.Any<CancellationToken>())
            .Returns(notification);
        var actor = CreateActor([]);

        actor.Tell(new DiscardNotificationRequest(
            CorrelationId: "test-corr", NotificationId: notification.NotificationId));

        // First wait for the discard handler to reply (handshake), then assert
        // the audit row landed.
        ExpectMsg<DiscardNotificationResponse>(r => r.Success);
        AwaitAssert(() =>
        {
            var discarded = EventsByStatus(AuditStatus.Discarded);
            Assert.Single(discarded);
            Assert.Equal(AuditKind.NotifyDeliver, discarded[0].Kind);
        });
    }

    [Fact]
    public void AuditWriter_Throws_TerminalUpdate_StillSucceeds()
    {
        // Audit failure NEVER aborts the user-facing action: the dispatcher
        // must still persist the Delivered status via UpdateAsync.
        SetupSmtpRetryPolicy(maxRetries: 5, retryDelay: TimeSpan.FromMinutes(1));
        var notification = MakeNotification();
        _outboxRepository.GetDueAsync(Arg.Any<DateTimeOffset>(), Arg.Any<int>(), Arg.Any<CancellationToken>())
            .Returns(new[] { notification });
        var adapter = new StubAdapter(() => DeliveryOutcome.Success("ops@example.com"));
        _auditWriter.OnWrite = _ => throw new InvalidOperationException("audit dead");
        var actor = CreateActor([adapter]);

        actor.Tell(InternalMessages.DispatchTick.Instance);

        AwaitAssert(() =>
        {
            _outboxRepository.Received(1).UpdateAsync(
                Arg.Is<Notification>(n => n.Status == NotificationStatus.Delivered),
                Arg.Any<CancellationToken>());
        });
    }
}