using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;

namespace ZB.MOM.WW.OtOpcUa.Driver.S7.IntegrationTests.S7_1500;

/// <summary>
///     End-to-end coverage for the S7 driver's diagnostics surface against the python-snap7
///     S7-1500 simulator. The simulator runs the upstream Snap7 server which negotiates a
///     fixed 240-byte PDU during the COTP handshake; this suite asserts the driver captures
///     and surfaces that value through <c>DriverHealth.Diagnostics["S7.NegotiatedPduSize"]</c>
///     so the Admin UI driver-diagnostics panel can render it.
/// </summary>
[Collection(Snap7ServerCollection.Name)]
[Trait("Category", "Integration")]
[Trait("Device", "S7_1500")]
public sealed class S7_1500DiagnosticsTests(Snap7ServerFixture sim)
{
    [Fact]
    public async Task Driver_exposes_negotiated_pdu_size_post_init()
    {
        if (sim.SkipReason is not null) Assert.Skip(sim.SkipReason);

        var options = S7_1500Profile.BuildOptions(sim.Host, sim.Port);
        await using var drv = new S7Driver(options, driverInstanceId: "s7-pdu-diag");
        await drv.InitializeAsync("{}", TestContext.Current.CancellationToken);

        // Issue a read so BuildDiagnostics() flows into _health.Diagnostics through the
        // Healthy state-transition (the post-OpenAsync construction also seeds it, but we
        // exercise the read path too so the assertion is robust against future refactors
        // that move the seed point).
        var snapshots = await drv.ReadAsync(
            [S7_1500Profile.ProbeTag], TestContext.Current.CancellationToken);
        snapshots[0].StatusCode.ShouldBe(0u, "probe read must succeed before checking diagnostics");

        var diagnostics = drv.GetHealth().DiagnosticsOrEmpty;
        diagnostics.ContainsKey("S7.NegotiatedPduSize").ShouldBeTrue(
            "S7 driver must surface negotiated PDU size as S7.NegotiatedPduSize");
        diagnostics["S7.NegotiatedPduSize"].ShouldBeGreaterThan(0,
            "Snap7 negotiates a 240-byte PDU on every COTP handshake — anything ≤ 0 means the snapshot was missed");
    }
}