using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.PlcFamilies;

namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.IntegrationTests;

/// <summary>
///     Review 07 P7: a coalesced read of nearby N7 words and bits must decode exactly what per-tag reads return,
///     on the wire, on both transports. Seeds distinct values first when writes are allowed (simulator only);
///     otherwise compares whatever the simulator holds.
/// </summary>
[Collection(AbLegacyServerCollection.Name)]
[Trait("Category", "Integration")]
[Trait("Simulator", "ab_server-PCCC")]
public sealed class AbLegacyReadCoalescingIntegrationTests(AbLegacyServerFixture sim)
{
    /// <summary>Coalesced and per-tag reads of the same tags agree value for value.</summary>
    /// <param name="profile">The simulator profile.</param>
    /// <param name="transport">The transport stack the driver runs on.</param>
    [AbLegacyTheory]
    [MemberData(nameof(TransportMatrix.Profiles), MemberType = typeof(TransportMatrix))]
    public async Task Coalesced_reads_match_single_reads(AbLegacyServerProfile profile, AbLegacyTransport transport)
    {
        if (sim.SkipReasonFor(profile) is { } skip) Assert.Skip(skip);
        var ct = TestContext.Current.CancellationToken;
        var uri = $"ab://{sim.Host}:{sim.PortFor(profile)}/{sim.CipPath}";
        AbLegacyTagDefinition[] tags =
        [
            new("W0", uri, "N7:0", AbLegacyDataType.Int),
            new("W1", uri, "N7:1", AbLegacyDataType.Int),
            new("W4", uri, "N7:4", AbLegacyDataType.Int),
            new("W4b3", uri, "N7:4/3", AbLegacyDataType.Bit),
        ];
        string[] refs = [.. tags.Select(t => t.Name)];

        AbLegacyDriver Make(bool coalesce) => new(new AbLegacyDriverOptions
        {
            Devices = [new AbLegacyDeviceOptions(uri, profile.Family)],
            RawTags = AbLegacyRawTags.Entries(tags),
            Timeout = TimeSpan.FromSeconds(5),
            Probe = new AbLegacyProbeOptions { Enabled = false },
            Transport = transport,
            CoalesceReads = coalesce,
        }, driverInstanceId: $"ablegacy-coalesce-{coalesce}-{profile.Family}-{transport}");

        await using var single = Make(coalesce: false);
        await using var coalesced = Make(coalesce: true);
        await single.InitializeAsync("{}", ct);
        await coalesced.InitializeAsync("{}", ct);

        var writesRefused = profile.Family == AbLegacyPlcFamily.Plc5 && transport == AbLegacyTransport.Native;
        if (Environment.GetEnvironmentVariable(IntegrationWriteGate.AllowWritesVar) == "1"
            && Environment.GetEnvironmentVariable(IntegrationWriteGate.DifferentialEndpointVar) is not { Length: > 0 }
            && !writesRefused)
        {
            (await single.WriteAsync(
                [new WriteRequest("W0", (short)101), new WriteRequest("W1", (short)-202), new WriteRequest("W4", (short)0x0008)], ct))
                .ShouldAllBe(r => r.StatusCode == AbLegacyStatusMapper.Good);
        }

        var a = await single.ReadAsync(refs, ct);
        var b = await coalesced.ReadAsync(refs, ct);

        a.ShouldAllBe(s => s.StatusCode == AbLegacyStatusMapper.Good);
        b.ShouldAllBe(s => s.StatusCode == AbLegacyStatusMapper.Good);
        b.Select(s => s.Value).ShouldBe(a.Select(s => s.Value));
    }

    /// <summary>
    ///     Review 07 r0 I1, on the wire: one coalesced member past the END of the file (the fixture's N7 holds 10
    ///     words) makes the PLC refuse the block with a real transport status (libplctag: ERR_REMOTE_ERR). Its
    ///     neighbours must still read Good on every poll, and the device must never be failed fast or degraded.
    /// </summary>
    /// <param name="profile">The simulator profile.</param>
    /// <param name="transport">The transport stack the driver runs on.</param>
    [AbLegacyTheory]
    [MemberData(nameof(TransportMatrix.Profiles), MemberType = typeof(TransportMatrix))]
    public async Task A_member_past_the_end_of_the_file_never_blacks_out_its_neighbours(
        AbLegacyServerProfile profile, AbLegacyTransport transport)
    {
        if (sim.SkipReasonFor(profile) is { } skip) Assert.Skip(skip);
        var ct = TestContext.Current.CancellationToken;
        var uri = $"ab://{sim.Host}:{sim.PortFor(profile)}/{sim.CipPath}";
        await using var drv = new AbLegacyDriver(new AbLegacyDriverOptions
        {
            Devices = [new AbLegacyDeviceOptions(uri, profile.Family)],
            RawTags = AbLegacyRawTags.Entries(
                new AbLegacyTagDefinition("A", uri, "N7:7", AbLegacyDataType.Int),
                new AbLegacyTagDefinition("B", uri, "N7:8", AbLegacyDataType.Int),
                new AbLegacyTagDefinition("PastEnd", uri, "N7:12", AbLegacyDataType.Int)),
            Timeout = TimeSpan.FromSeconds(5),
            Probe = new AbLegacyProbeOptions { Enabled = false },
            Transport = transport,
        }, driverInstanceId: $"ablegacy-pastend-{profile.Family}-{transport}");
        await drv.InitializeAsync("{}", ct);

        for (var poll = 0; poll < 3; poll++)
        {
            var r = await drv.ReadAsync(["A", "B", "PastEnd"], ct);
            r[0].StatusCode.ShouldBe(AbLegacyStatusMapper.Good, $"poll {poll}: neighbour A");
            r[1].StatusCode.ShouldBe(AbLegacyStatusMapper.Good, $"poll {poll}: neighbour B");
            r[2].StatusCode.ShouldNotBe(AbLegacyStatusMapper.Good, $"poll {poll}: the past-the-end tag");
        }
        // The refusal (libplctag: an opaque ERR_REMOTE_ERR; native: a mapped STS) is never a comms fault: the
        // answering neighbours keep the driver Healthy and the device is never failed fast.
        drv.GetHealth().State.ShouldBe(DriverState.Healthy);
    }

    /// <summary>
    ///     Review 07 r1 N1, on the wire: libplctag reports the past-the-end refusal as the OPAQUE ERR_REMOTE_ERR —
    ///     the same code a bridge returns for a powered-off PLC behind it — so a device whose ONLY traffic is that
    ///     reply must not look reachable: Degraded, <c>LastSuccessfulRead</c> frozen (the comms-loss watchdog's
    ///     evidence). The native transport maps the STS itself and is only checked to stay non-Good.
    /// </summary>
    /// <param name="profile">The simulator profile.</param>
    /// <param name="transport">The transport stack the driver runs on.</param>
    [AbLegacyTheory]
    [MemberData(nameof(TransportMatrix.Profiles), MemberType = typeof(TransportMatrix))]
    public async Task An_opaque_only_device_never_proves_reachability(AbLegacyServerProfile profile, AbLegacyTransport transport)
    {
        if (sim.SkipReasonFor(profile) is { } skip) Assert.Skip(skip);
        var ct = TestContext.Current.CancellationToken;
        var uri = $"ab://{sim.Host}:{sim.PortFor(profile)}/{sim.CipPath}";
        await using var drv = new AbLegacyDriver(new AbLegacyDriverOptions
        {
            Devices = [new AbLegacyDeviceOptions(uri, profile.Family)],
            RawTags = AbLegacyRawTags.Entries(new AbLegacyTagDefinition("PastEnd", uri, "N7:12", AbLegacyDataType.Int)),
            Timeout = TimeSpan.FromSeconds(5),
            Probe = new AbLegacyProbeOptions { Enabled = false },
            Transport = transport,
        }, driverInstanceId: $"ablegacy-opaque-{profile.Family}-{transport}");
        await drv.InitializeAsync("{}", ct);
        var initLastRead = drv.GetHealth().LastSuccessfulRead;
        await Task.Delay(20, ct);

        for (var poll = 0; poll < 2; poll++)
            (await drv.ReadAsync(["PastEnd"], ct))[0].StatusCode.ShouldNotBe(AbLegacyStatusMapper.Good);

        if (transport == AbLegacyTransport.Libplctag)
        {
            drv.GetHealth().State.ShouldBe(DriverState.Degraded);
            drv.GetHealth().LastSuccessfulRead.ShouldBe(initLastRead);
        }
    }
}