using ZB.MOM.WW.MxGateway.Client;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Config;
using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Runtime;

namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests.Runtime;

/// <summary>
///     Live meter legs for the 06/S-1 write-confirmation gate — the observation that closed the
///     archreview finding: against a correlated gateway (mxaccessgw server ≥ <c>b948e69</c>, worker ≥
///     <c>53f69cd</c>) every unary write reply carries the worker's <c>OnWriteComplete</c> outcome as
///     <c>statuses[0]</c>, so <c>galaxy.writes.unconfirmed</c> — which used to increment on EVERY
///     write — stays flat, and only a completion-wait timeout (or a pre-correlation gateway) meters.
///     <para>
///     ⚠️ Run these FILTERED (one test class), never as part of a full-assembly run with the env vars
///     set: the offline <see cref="GatewayGalaxyDataWriterTests"/> exercise the unconfirmed path
///     against fakes, and xunit runs test classes in parallel, so their increments would pollute the
///     process-wide counters these tests listen to.
///     </para>
/// </summary>
[Trait("Category", "Integration")]
public sealed class GatewayGalaxyWriteMeterLiveTests
{
    private const string WriteRef = "TestMachine_002.TestFloat";

    /// <summary>
    ///     Confirmed writes keep both write meters flat: five committed writes and one refusal, all
    ///     carrying a correlated status row — zero <c>unconfirmed</c> (the counter is presence-based,
    ///     so the refusal must not increment it either) and zero <c>advise_failed</c>.
    /// </summary>
    [Fact]
    public async Task Live_confirmed_writes_keep_unconfirmed_meter_flat()
    {
        var (endpoint, apiKey) = RequireLiveGatewayOrSkip();

        long unconfirmed = 0;
        long adviseFailed = 0;
        using var listener = new System.Diagnostics.Metrics.MeterListener();
        listener.InstrumentPublished = (instrument, l) =>
        {
            if (instrument.Name is "galaxy.writes.unconfirmed" or "galaxy.writes.advise_failed")
                l.EnableMeasurementEvents(instrument);
        };
        listener.SetMeasurementEventCallback<long>((instrument, value, _, _) =>
        {
            if (instrument.Name == "galaxy.writes.unconfirmed") Interlocked.Add(ref unconfirmed, value);
            else Interlocked.Add(ref adviseFailed, value);
        });
        listener.Start();

        var ct = TestContext.Current.CancellationToken;
        await using var session = new GalaxyMxSession(new GalaxyMxAccessOptions(ClientName: "OtOpcUa06S1Meter"));
        await session.ConnectAsync(BuildClientOptions(endpoint, apiKey), ct);
        var writer = new GatewayGalaxyDataWriter(session, writeUserId: 0);

        for (var i = 0; i < 5; i++)
        {
            var r = await writer.WriteAsync(
                [new WriteRequest(WriteRef, 7000.0f + i)], _ => SecurityClassification.FreeAccess, ct);
            Assert.Equal(0u, r[0].StatusCode);
        }
        var refused = await writer.WriteAsync(
            [new WriteRequest("TestMachine_002.Tagname", "meter-leg-refusal")],
            _ => SecurityClassification.FreeAccess, ct);
        Assert.Equal(2u, (refused[0].StatusCode >> 30) & 0x3u);

        listener.Dispose();
        Assert.Equal(0, Interlocked.Read(ref unconfirmed));
        Assert.Equal(0, Interlocked.Read(ref adviseFailed));
    }

    /// <summary>
    ///     Timeout-control leg — run ONLY while the target gateway has the completion wait disabled
    ///     (<c>MxGateway__Worker__WriteCompletionWaitMilliseconds=0</c>, an NSSM env-var flip +
    ///     service restart on a deployed instance): every reply is then empty-statuses, so the writer
    ///     reports provisional Good and meters each write unconfirmed. Gated on
    ///     <c>MXGW_WRITE_WAIT_DISABLED=1</c> so it can never run (and fail) against a
    ///     normally-configured gateway. Remove the override (same nssm command with <c>-</c>) and
    ///     restart afterwards; <see cref="Live_confirmed_writes_keep_unconfirmed_meter_flat"/>
    ///     passing again proves the restoration.
    /// </summary>
    [Fact]
    public async Task Live_wait_disabled_gateway_yields_provisional_good_and_metered_unconfirmed()
    {
        if (Environment.GetEnvironmentVariable("MXGW_WRITE_WAIT_DISABLED") != "1")
            Assert.Skip("Set MXGW_WRITE_WAIT_DISABLED=1 (with the gateway's completion wait set to 0) to run the timeout leg.");
        var (endpoint, apiKey) = RequireLiveGatewayOrSkip();

        long unconfirmed = 0;
        using var listener = new System.Diagnostics.Metrics.MeterListener();
        listener.InstrumentPublished = (instrument, l) =>
        {
            if (instrument.Name == "galaxy.writes.unconfirmed") l.EnableMeasurementEvents(instrument);
        };
        listener.SetMeasurementEventCallback<long>((_, value, _, _) => Interlocked.Add(ref unconfirmed, value));
        listener.Start();

        var ct = TestContext.Current.CancellationToken;
        await using var session = new GalaxyMxSession(new GalaxyMxAccessOptions(ClientName: "OtOpcUa06S1Leg3"));
        await session.ConnectAsync(BuildClientOptions(endpoint, apiKey), ct);
        var writer = new GatewayGalaxyDataWriter(session, writeUserId: 0);

        for (var i = 0; i < 3; i++)
        {
            var r = await writer.WriteAsync(
                [new WriteRequest(WriteRef, 7100.0f + i)], _ => SecurityClassification.FreeAccess, ct);
            Assert.Equal(0u, r[0].StatusCode); // provisional Good off the empty-statuses reply
        }

        listener.Dispose();
        Assert.Equal(3, Interlocked.Read(ref unconfirmed));
    }

    private static (string Endpoint, string ApiKey) RequireLiveGatewayOrSkip()
    {
        var endpoint = Environment.GetEnvironmentVariable("MXGW_ENDPOINT");
        var apiKey = Environment.GetEnvironmentVariable("GALAXY_MXGW_API_KEY");
        if (string.IsNullOrWhiteSpace(endpoint) || string.IsNullOrWhiteSpace(apiKey))
            Assert.Skip("Set MXGW_ENDPOINT + GALAXY_MXGW_API_KEY to run the live write-meter legs.");
        return (endpoint!, apiKey!);
    }

    private static MxGatewayClientOptions BuildClientOptions(string endpoint, string apiKey) => new()
    {
        Endpoint = new Uri(endpoint, UriKind.Absolute),
        ApiKey = apiKey,
        UseTls = false,
        ConnectTimeout = TimeSpan.FromSeconds(10),
        DefaultCallTimeout = TimeSpan.FromSeconds(30),
        StreamTimeout = TimeSpan.FromSeconds(30),
    };
}