using Microsoft.Extensions.Logging.Abstractions;
using Moq;
using ScadaLink.Commons.Entities.Audit;
using ScadaLink.Commons.Interfaces.Services;
using ScadaLink.Commons.Messages.Integration;
using ScadaLink.Commons.Types;
using ScadaLink.Commons.Types.Enums;
using ScadaLink.SiteRuntime.Scripts;

namespace ScadaLink.SiteRuntime.Tests.Scripts;

/// <summary>
/// Audit Log #23 — M3 Bundle E (Task E3): every script-initiated
/// <c>ExternalSystem.CachedCall</c> emits exactly one <c>CachedSubmit</c>
/// combined-telemetry packet at enqueue time, returns a fresh
/// <see cref="TrackedOperationId"/>, and threads that id down to the
/// store-and-forward layer so the retry-loop emissions (Tasks E4/E5) can join
/// them by id. The audit emission is best-effort: a thrown forwarder must
/// never abort the script's call, and the original
/// <see cref="ExternalCallResult"/> must surface to the caller unchanged.
/// </summary>
public class ExternalSystemCachedCallEmissionTests
{
    private sealed class CapturingForwarder : ICachedCallTelemetryForwarder
    {
        public List<CachedCallTelemetry> Telemetry { get; } = new();
        public Exception? ThrowOnForward { get; set; }

        public Task ForwardAsync(CachedCallTelemetry telemetry, CancellationToken ct = default)
        {
            if (ThrowOnForward != null)
            {
                return Task.FromException(ThrowOnForward);
            }
            Telemetry.Add(telemetry);
            return Task.CompletedTask;
        }
    }

    private const string SiteId = "site-77";
    private const string InstanceName = "Plant.Pump42";
    private const string SourceScript = "ScriptActor:CheckPressure";

    private static ScriptRuntimeContext.ExternalSystemHelper CreateHelper(
        IExternalSystemClient client,
        ICachedCallTelemetryForwarder? forwarder)
    {
        return new ScriptRuntimeContext.ExternalSystemHelper(
            client,
            InstanceName,
            NullLogger.Instance,
            auditWriter: null,
            siteId: SiteId,
            sourceScript: SourceScript,
            cachedForwarder: forwarder);
    }

    [Fact]
    public async Task CachedCall_EmitsSubmitTelemetry_OnEnqueue()
    {
        var client = new Mock<IExternalSystemClient>();
        client
            .Setup(c => c.CachedCallAsync(
                "ERP", "GetOrder",
                It.IsAny<IReadOnlyDictionary<string, object?>?>(),
                InstanceName,
                It.IsAny<CancellationToken>(),
                It.IsAny<TrackedOperationId?>()))
            .ReturnsAsync(new ExternalCallResult(true, null, null, WasBuffered: true));
        var forwarder = new CapturingForwarder();

        var helper = CreateHelper(client.Object, forwarder);
        var trackedId = await helper.CachedCall("ERP", "GetOrder");

        Assert.NotEqual(default, trackedId);
        Assert.Single(forwarder.Telemetry);
        var packet = forwarder.Telemetry[0];

        Assert.Equal(AuditChannel.ApiOutbound, packet.Audit.Channel);
        Assert.Equal(AuditKind.CachedSubmit, packet.Audit.Kind);
        Assert.Equal(AuditStatus.Submitted, packet.Audit.Status);
        Assert.Equal("ERP.GetOrder", packet.Audit.Target);
        Assert.Equal(trackedId.Value, packet.Audit.CorrelationId);
        Assert.Equal(AuditForwardState.Pending, packet.Audit.ForwardState);

        // Operational mirror — same id, Submitted, RetryCount 0, not terminal.
        Assert.Equal(trackedId, packet.Operational.TrackedOperationId);
        Assert.Equal("ApiOutbound", packet.Operational.Channel);
        Assert.Equal("ERP.GetOrder", packet.Operational.Target);
        Assert.Equal(SiteId, packet.Operational.SourceSite);
        Assert.Equal("Submitted", packet.Operational.Status);
        Assert.Equal(0, packet.Operational.RetryCount);
        Assert.Null(packet.Operational.LastError);
        Assert.Null(packet.Operational.TerminalAtUtc);
    }

    [Fact]
    public async Task CachedCall_ReturnsTrackedOperationId()
    {
        var client = new Mock<IExternalSystemClient>();
        client
            .Setup(c => c.CachedCallAsync(
                It.IsAny<string>(), It.IsAny<string>(),
                It.IsAny<IReadOnlyDictionary<string, object?>?>(),
                It.IsAny<string?>(),
                It.IsAny<CancellationToken>(),
                It.IsAny<TrackedOperationId?>()))
            .ReturnsAsync(new ExternalCallResult(true, null, null, WasBuffered: true));
        var forwarder = new CapturingForwarder();

        var helper = CreateHelper(client.Object, forwarder);

        var id1 = await helper.CachedCall("ERP", "GetOrder");
        var id2 = await helper.CachedCall("ERP", "GetOrder");

        Assert.NotEqual(default, id1);
        Assert.NotEqual(default, id2);
        Assert.NotEqual(id1, id2);

        // Both ids were threaded into the client invocations.
        client.Verify(c => c.CachedCallAsync(
            "ERP", "GetOrder",
            It.IsAny<IReadOnlyDictionary<string, object?>?>(),
            InstanceName,
            It.IsAny<CancellationToken>(),
            id1),
            Times.Once);
        client.Verify(c => c.CachedCallAsync(
            "ERP", "GetOrder",
            It.IsAny<IReadOnlyDictionary<string, object?>?>(),
            InstanceName,
            It.IsAny<CancellationToken>(),
            id2),
            Times.Once);
    }

    [Fact]
    public async Task CachedCall_ForwarderThrows_StillReturnsTrackedOperationId_OriginalCallProceeds()
    {
        var client = new Mock<IExternalSystemClient>();
        client
            .Setup(c => c.CachedCallAsync(
                It.IsAny<string>(), It.IsAny<string>(),
                It.IsAny<IReadOnlyDictionary<string, object?>?>(),
                It.IsAny<string?>(),
                It.IsAny<CancellationToken>(),
                It.IsAny<TrackedOperationId?>()))
            .ReturnsAsync(new ExternalCallResult(true, null, null, WasBuffered: true));
        var forwarder = new CapturingForwarder
        {
            ThrowOnForward = new InvalidOperationException("simulated forwarder outage"),
        };

        var helper = CreateHelper(client.Object, forwarder);

        // Must not throw — best-effort emission contract.
        var trackedId = await helper.CachedCall("ERP", "GetOrder");

        Assert.NotEqual(default, trackedId);
        // The underlying call still ran exactly once.
        client.Verify(c => c.CachedCallAsync(
            "ERP", "GetOrder",
            It.IsAny<IReadOnlyDictionary<string, object?>?>(),
            InstanceName,
            It.IsAny<CancellationToken>(),
            trackedId),
            Times.Once);
    }

    [Fact]
    public async Task CachedCall_Provenance_Populated_FromContext()
    {
        var client = new Mock<IExternalSystemClient>();
        client
            .Setup(c => c.CachedCallAsync(
                It.IsAny<string>(), It.IsAny<string>(),
                It.IsAny<IReadOnlyDictionary<string, object?>?>(),
                It.IsAny<string?>(),
                It.IsAny<CancellationToken>(),
                It.IsAny<TrackedOperationId?>()))
            .ReturnsAsync(new ExternalCallResult(true, null, null, WasBuffered: true));
        var forwarder = new CapturingForwarder();

        var helper = CreateHelper(client.Object, forwarder);
        await helper.CachedCall("ERP", "GetOrder");

        var packet = Assert.Single(forwarder.Telemetry);
        Assert.Equal(SiteId, packet.Audit.SourceSiteId);
        Assert.Equal(InstanceName, packet.Audit.SourceInstanceId);
        Assert.Equal(SourceScript, packet.Audit.SourceScript);
        Assert.Equal(SiteId, packet.Operational.SourceSite);
    }

    [Fact]
    public async Task CachedCall_NoForwarder_StillReturnsTrackedOperationId()
    {
        // Forwarder not wired (tests / minimal hosts) — must still return a
        // fresh id and invoke the underlying call.
        var client = new Mock<IExternalSystemClient>();
        client
            .Setup(c => c.CachedCallAsync(
                It.IsAny<string>(), It.IsAny<string>(),
                It.IsAny<IReadOnlyDictionary<string, object?>?>(),
                It.IsAny<string?>(),
                It.IsAny<CancellationToken>(),
                It.IsAny<TrackedOperationId?>()))
            .ReturnsAsync(new ExternalCallResult(true, null, null, WasBuffered: true));

        var helper = CreateHelper(client.Object, forwarder: null);
        var trackedId = await helper.CachedCall("ERP", "GetOrder");

        Assert.NotEqual(default, trackedId);
        client.Verify(c => c.CachedCallAsync(
            "ERP", "GetOrder",
            It.IsAny<IReadOnlyDictionary<string, object?>?>(),
            InstanceName,
            It.IsAny<CancellationToken>(),
            trackedId),
            Times.Once);
    }

    /// <summary>
    /// Audit Log #23 — M3 Bundle F (F2): when the underlying client call
    /// completes immediately (no S&amp;F buffering, <c>WasBuffered=false</c>),
    /// the S&amp;F retry loop never engages and the
    /// <c>ICachedCallLifecycleObserver</c> hook never fires. The cached-call
    /// helper itself must therefore emit the terminal lifecycle rows —
    /// otherwise <c>Tracking.Status(id)</c> would return <c>Submitted</c>
    /// forever and the audit log would be missing the <c>Attempted</c> /
    /// <c>CachedResolve</c> pair the M3 contract requires.
    ///
    /// Expected emissions on immediate success:
    ///   1. CachedSubmit / Submitted  (already covered)
    ///   2. ApiCallCached / Attempted
    ///   3. CachedResolve / Delivered (TerminalAtUtc set)
    /// </summary>
    [Fact]
    public async Task CachedCall_ImmediateSuccess_EmitsAttemptedAndCachedResolve()
    {
        var client = new Mock<IExternalSystemClient>();
        client
            .Setup(c => c.CachedCallAsync(
                "ERP", "GetOrder",
                It.IsAny<IReadOnlyDictionary<string, object?>?>(),
                InstanceName,
                It.IsAny<CancellationToken>(),
                It.IsAny<TrackedOperationId?>()))
            // WasBuffered=false — the immediate HTTP attempt succeeded; S&F
            // is bypassed entirely.
            .ReturnsAsync(new ExternalCallResult(true, "{\"ok\":true}", null, WasBuffered: false));
        var forwarder = new CapturingForwarder();

        var helper = CreateHelper(client.Object, forwarder);
        var trackedId = await helper.CachedCall("ERP", "GetOrder");

        // Three telemetry packets emitted: Submit, Attempted, Resolve.
        Assert.Equal(3, forwarder.Telemetry.Count);

        var submit = forwarder.Telemetry[0];
        Assert.Equal(AuditKind.CachedSubmit, submit.Audit.Kind);
        Assert.Equal(AuditStatus.Submitted, submit.Audit.Status);
        Assert.Equal(trackedId, submit.Operational.TrackedOperationId);
        Assert.Null(submit.Operational.TerminalAtUtc);

        var attempted = forwarder.Telemetry[1];
        Assert.Equal(AuditChannel.ApiOutbound, attempted.Audit.Channel);
        Assert.Equal(AuditKind.ApiCallCached, attempted.Audit.Kind);
        Assert.Equal(AuditStatus.Attempted, attempted.Audit.Status);
        Assert.Equal(trackedId.Value, attempted.Audit.CorrelationId);
        Assert.Equal("ERP.GetOrder", attempted.Audit.Target);
        Assert.Equal(trackedId, attempted.Operational.TrackedOperationId);
        Assert.Equal("Attempted", attempted.Operational.Status);
        Assert.Null(attempted.Operational.TerminalAtUtc);

        var resolve = forwarder.Telemetry[2];
        Assert.Equal(AuditChannel.ApiOutbound, resolve.Audit.Channel);
        Assert.Equal(AuditKind.CachedResolve, resolve.Audit.Kind);
        Assert.Equal(AuditStatus.Delivered, resolve.Audit.Status);
        Assert.Equal(trackedId.Value, resolve.Audit.CorrelationId);
        Assert.Equal(trackedId, resolve.Operational.TrackedOperationId);
        Assert.Equal("Delivered", resolve.Operational.Status);
        // Terminal row carries TerminalAtUtc.
        Assert.NotNull(resolve.Operational.TerminalAtUtc);
    }

    /// <summary>
    /// Audit Log #23 — M3 Bundle F (F2): the immediate-failure terminal
    /// path. When the client returns <c>Success=false</c> with
    /// <c>WasBuffered=false</c> (a permanent failure or a transient failure
    /// without an S&amp;F engine to buffer it), the cached-call helper must
    /// still emit Attempted + CachedResolve with the failed status.
    /// </summary>
    [Fact]
    public async Task CachedCall_ImmediateFailure_EmitsAttemptedAndCachedResolveFailed()
    {
        var client = new Mock<IExternalSystemClient>();
        client
            .Setup(c => c.CachedCallAsync(
                "ERP", "GetOrder",
                It.IsAny<IReadOnlyDictionary<string, object?>?>(),
                InstanceName,
                It.IsAny<CancellationToken>(),
                It.IsAny<TrackedOperationId?>()))
            .ReturnsAsync(new ExternalCallResult(
                false, null, "Permanent error: HTTP 422 bad payload", WasBuffered: false));
        var forwarder = new CapturingForwarder();

        var helper = CreateHelper(client.Object, forwarder);
        var trackedId = await helper.CachedCall("ERP", "GetOrder");

        Assert.Equal(3, forwarder.Telemetry.Count);

        var attempted = forwarder.Telemetry[1];
        Assert.Equal(AuditKind.ApiCallCached, attempted.Audit.Kind);
        Assert.Equal(AuditStatus.Attempted, attempted.Audit.Status);
        // The per-attempt row carries the error message.
        Assert.NotNull(attempted.Audit.ErrorMessage);

        var resolve = forwarder.Telemetry[2];
        Assert.Equal(AuditKind.CachedResolve, resolve.Audit.Kind);
        // Immediate permanent failure -> Failed audit status / operational Failed.
        Assert.Equal(AuditStatus.Failed, resolve.Audit.Status);
        Assert.Equal("Failed", resolve.Operational.Status);
        Assert.NotNull(resolve.Operational.TerminalAtUtc);
        Assert.NotNull(resolve.Operational.LastError);
    }

    /// <summary>
    /// Audit Log #23 — M3 Bundle F (F2): when the client reports
    /// <c>WasBuffered=true</c>, the helper hands the operation to S&amp;F and
    /// the retry-loop observer owns the Attempted + Resolve emissions. The
    /// helper must NOT emit those rows itself (otherwise we'd get duplicate
    /// Attempted + Resolve audit rows under the same tracking id).
    /// </summary>
    [Fact]
    public async Task CachedCall_BufferedPath_DoesNotEmitTerminalTelemetryFromHelper()
    {
        var client = new Mock<IExternalSystemClient>();
        client
            .Setup(c => c.CachedCallAsync(
                "ERP", "GetOrder",
                It.IsAny<IReadOnlyDictionary<string, object?>?>(),
                InstanceName,
                It.IsAny<CancellationToken>(),
                It.IsAny<TrackedOperationId?>()))
            // S&F took ownership — Attempted + Resolve come from the
            // CachedCallLifecycleBridge driven by the retry loop, not the helper.
            .ReturnsAsync(new ExternalCallResult(true, null, null, WasBuffered: true));
        var forwarder = new CapturingForwarder();

        var helper = CreateHelper(client.Object, forwarder);
        await helper.CachedCall("ERP", "GetOrder");

        // Only the CachedSubmit row — no Attempted / Resolve from the helper.
        var only = Assert.Single(forwarder.Telemetry);
        Assert.Equal(AuditKind.CachedSubmit, only.Audit.Kind);
    }
}