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

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

/// <summary>
///     PR abcip-4.3 — end-to-end coverage that the synthetic <c>_System</c> folder + its five
///     diagnostic variables ride a real ab_server lifecycle. Skipped when the binary isn't
///     on PATH (<see cref="AbServerFactAttribute"/>).
/// </summary>
[Trait("Category", "Integration")]
[Trait("Requires", "AbServer")]
public sealed class AbCipSystemTagDiscoveryTests
{
    [AbServerFact]
    public async Task System_folder_browses_and_each_variable_reads_non_empty()
    {
        var profile = KnownProfiles.ControlLogix;
        var fixture = new AbServerFixture(profile);
        await fixture.InitializeAsync();
        try
        {
            var deviceUri = $"ab://127.0.0.1:{fixture.Port}/1,0";
            var drv = new AbCipDriver(new AbCipDriverOptions
            {
                Devices = [new AbCipDeviceOptions(deviceUri, profile.Family)],
                Tags = [new AbCipTagDefinition("Counter", deviceUri, "TestDINT", AbCipDataType.DInt)],
                Timeout = TimeSpan.FromSeconds(5),
            }, "drv-system-tags");

            await drv.InitializeAsync("{}", CancellationToken.None);

            // Discovery — five system variables exposed under _System/ for the device.
            var builder = new RecordingBuilder();
            await drv.DiscoverAsync(builder, CancellationToken.None);

            builder.Folders.ShouldContain(f => f.BrowseName == "_System");
            var systemVars = builder.Variables
                .Where(v => v.Info.FullName.StartsWith("_System/"))
                .Select(v => v.BrowseName)
                .ToList();
            systemVars.ShouldContain("_ConnectionStatus");
            systemVars.ShouldContain("_ScanRate");
            systemVars.ShouldContain("_TagCount");
            systemVars.ShouldContain("_DeviceError");
            systemVars.ShouldContain("_LastScanTimeMs");

            // Read — each system variable returns Good with a non-null value, with no
            // libplctag round-trip required.
            var refs = systemVars
                .Select(name => $"_System/{deviceUri}/{name}")
                .ToList();
            var snaps = await drv.ReadAsync(refs, CancellationToken.None);
            for (var i = 0; i < snaps.Count; i++)
            {
                snaps[i].StatusCode.ShouldBe(AbCipStatusMapper.Good,
                    $"system variable {refs[i]} should read Good");
                snaps[i].Value.ShouldNotBeNull(
                    $"system variable {refs[i]} should not be null");
            }

            await drv.ShutdownAsync(CancellationToken.None);
        }
        finally
        {
            await fixture.DisposeAsync();
        }
    }

    private sealed class RecordingBuilder : IAddressSpaceBuilder
    {
        public List<(string BrowseName, string DisplayName)> Folders { get; } = new();
        public List<(string BrowseName, DriverAttributeInfo Info)> Variables { get; } = new();

        public IAddressSpaceBuilder Folder(string browseName, string displayName)
        { Folders.Add((browseName, displayName)); return this; }

        public IVariableHandle Variable(string browseName, string displayName, DriverAttributeInfo info)
        { Variables.Add((browseName, info)); return new Handle(info.FullName); }

        public void AddProperty(string _, DriverDataType __, object? ___) { }

        private sealed class Handle(string fullRef) : IVariableHandle
        {
            public string FullReference => fullRef;
            public IAlarmConditionSink MarkAsAlarmCondition(AlarmConditionInfo info) => new NullSink();
        }
        private sealed class NullSink : IAlarmConditionSink
        {
            public void OnTransition(AlarmEventArgs args) { }
        }
    }
}