using Grpc.Core;
using ZB.MOM.WW.ScadaBridge.Communication.Grpc;

namespace ZB.MOM.WW.ScadaBridge.Communication.Tests.Grpc;

public class AuditWireBudgetTests
{
    /// <summary>Verifies that a row over the soft budget travels alone in its batch without being truncated.</summary>
    [Fact]
    public void OversizeSoftBudgetRow_TravelsAloneWithoutTruncation()
    {
        var batch = new AuditEventBatch();
        var bytes = AuditWireBudget.InitialBytes;
        var row = new AuditEventDto { EventId = "large", ErrorDetail = new string('x', GrpcMessageLimits.AuditBatchBytes + 1) };
        Assert.True(AuditWireBudget.TryAppend(batch.Events, row, ref bytes, row.EventId));
        Assert.False(AuditWireBudget.TryAppend(batch.Events, new AuditEventDto { EventId = "next" }, ref bytes, "next"));
        Assert.Same(row, Assert.Single(batch.Events));
        Assert.Equal(row.ErrorDetail, batch.Events[0].ErrorDetail);
        Assert.True(bytes < GrpcMessageLimits.MaxMessageBytes);
    }

    /// <summary>Verifies that a hard-oversize row does not block the rows before it and fails explicitly when it is first in a batch.</summary>
    [Fact]
    public void HardOversizeRow_DoesNotBlockGoodPrefix_AndFailsExplicitlyWhenFirst()
    {
        var good = new AuditEventDto { EventId = "good", ErrorMessage = "small" };
        var huge = new AuditEventDto { EventId = "retained-id", ErrorDetail = new string('x', GrpcMessageLimits.MaxMessageBytes) };
        var batch = new AuditEventBatch();
        var bytes = AuditWireBudget.InitialBytes;
        Assert.True(AuditWireBudget.TryAppend(batch.Events, good, ref bytes, good.EventId));
        Assert.False(AuditWireBudget.TryAppend(batch.Events, huge, ref bytes, huge.EventId));
        Assert.Equal("good", Assert.Single(batch.Events).EventId);
        var next = new AuditEventBatch();
        bytes = AuditWireBudget.InitialBytes;
        var ex = Assert.Throws<RpcException>(() => AuditWireBudget.TryAppend(next.Events, huge, ref bytes, huge.EventId));
        Assert.Equal(StatusCode.ResourceExhausted, ex.StatusCode);
        Assert.Contains("retained-id", ex.Status.Detail);
        Assert.Contains("retained locally", ex.Status.Detail);
        Assert.Empty(next.Events);
    }
}