using System.Reflection;
using AVEVA.Historian.Client.Grpc;
using Xunit;

namespace AVEVA.Historian.Client.Tests;

/// <summary>
/// Reflection guard for the event-on-session seams the B0b reuse spike drives (pending.md A1
/// broadening, Stage B0). Mirrors <see cref="TagClientOnSessionSeamTests"/>: the seam runs ONLY the
/// op against an externally-supplied (connection, session), so the spike can run MULTIPLE event ops
/// on one already-opened + registered v8 Event session to measure reuse.
/// </summary>
public class EventOnSessionSeamTests
{
    private static MethodInfo RequireMethod(Type owner, string name)
    {
        MethodInfo? m = owner.GetMethod(
            name, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public | BindingFlags.Static);
        Assert.NotNull(m);
        return m!;
    }

    [Fact]
    public void SendEventOnSession_ExposesSeam_WithConnectionAndSessionFirst()
    {
        MethodInfo m = RequireMethod(typeof(HistorianGrpcEventWriteOrchestrator), "SendEventOnSession");
        ParameterInfo[] ps = m.GetParameters();
        Assert.Equal("HistorianGrpcConnection", ps[0].ParameterType.Name);
        Assert.Equal("Session", ps[1].ParameterType.Name);
    }

    [Fact]
    public void OpenAndRegisterEventSession_ExposesRegisterOnceSeam()
    {
        // The spike registers CM_EVENT ONCE via this helper, then issues many SendEventOnSession ops.
        MethodInfo m = RequireMethod(typeof(HistorianGrpcEventWriteOrchestrator), "OpenAndRegisterEventSession");
        ParameterInfo[] ps = m.GetParameters();
        Assert.Equal("HistorianGrpcConnection", ps[0].ParameterType.Name);
        Assert.Equal("CancellationToken", ps[1].ParameterType.Name);
        Assert.Equal("Session", m.ReturnType.Name);
    }

    [Fact]
    public void RunEventQueryOnSession_ExposesSeam_WithConnectionAndSessionFirst()
    {
        MethodInfo m = RequireMethod(typeof(HistorianGrpcEventOrchestrator), "RunEventQueryOnSession");
        ParameterInfo[] ps = m.GetParameters();
        Assert.Equal("HistorianGrpcConnection", ps[0].ParameterType.Name);
        Assert.Equal("Session", ps[1].ParameterType.Name);
    }
}