using ZB.MOM.WW.ScadaBridge.AuditLog.Site.Telemetry;
using ZB.MOM.WW.ScadaBridge.Communication.Grpc;

namespace ZB.MOM.WW.ScadaBridge.AuditLog.Tests.Site.Telemetry;

/// <summary>
/// Tests for <see cref="NoOpSiteStreamAuditClient"/>. The NoOp
/// client is the default <see cref="ISiteStreamAuditClient"/> binding until the
/// gRPC-backed implementation is delivered; both <c>IngestAuditEventsAsync</c>
/// and <c>IngestCachedTelemetryAsync</c> must return an empty ack
/// (no rows flipped to Forwarded) without throwing or partially handling the
/// batch.
/// </summary>
public class NoOpSiteStreamAuditClientTests
{
    /// <summary>Verifies that ingesting an empty cached-telemetry batch returns an empty acknowledgement.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task IngestCachedTelemetryAsync_EmptyBatch_ReturnsEmptyAck()
    {
        var sut = new NoOpSiteStreamAuditClient();
        var batch = new CachedTelemetryBatch();

        var ack = await sut.IngestCachedTelemetryAsync(batch, CancellationToken.None);

        Assert.NotNull(ack);
        Assert.Empty(ack.AcceptedEventIds);
    }

    /// <summary>Verifies that ingesting a populated batch still returns an empty acknowledgement, because the no-op client forwards nothing.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task IngestCachedTelemetryAsync_PopulatedBatch_ReturnsEmptyAck()
    {
        var sut = new NoOpSiteStreamAuditClient();
        var batch = new CachedTelemetryBatch();
        batch.Packets.Add(new CachedTelemetryPacket
        {
            AuditEvent = new AuditEventDto
            {
                EventId = Guid.NewGuid().ToString(),
                Channel = "ApiOutbound",
                Kind = "CachedSubmit",
                Status = "Submitted",
            },
        });

        var ack = await sut.IngestCachedTelemetryAsync(batch, CancellationToken.None);

        // No EventIds flipped — NoOp does not forward to anyone.
        Assert.Empty(ack.AcceptedEventIds);
    }

    /// <summary>Verifies that ingesting a null batch throws an <see cref="ArgumentNullException"/>.</summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task IngestCachedTelemetryAsync_NullBatch_Throws()
    {
        var sut = new NoOpSiteStreamAuditClient();

        await Assert.ThrowsAsync<ArgumentNullException>(
            () => sut.IngestCachedTelemetryAsync(null!, CancellationToken.None));
    }
}