using System.Collections.Concurrent;
using Microsoft.Extensions.Logging.Abstractions;
using Opc.Ua.Server;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;

namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests;

/// <summary>
/// #85 — verifies <see cref="Phase7Applier.MaterialiseHierarchy"/> builds the UNS
/// Area/Line/Equipment folder tree through <see cref="IOpcUaAddressSpaceSink.EnsureFolder"/>.
/// One pure unit test (recording sink) confirms ordering + parenting; one boot-verify test
/// drives a real <see cref="OtOpcUaNodeManager"/> and inspects the resulting predefined-node
/// count to prove the folders land in the SDK address space.
/// </summary>
public sealed class Phase7ApplierHierarchyTests : IDisposable
{
    private static CancellationToken Ct => TestContext.Current.CancellationToken;

    private readonly string _pkiRoot = Path.Combine(
        Path.GetTempPath(),
        $"otopcua-pki-{Guid.NewGuid():N}");

    [Fact]
    public void MaterialiseHierarchy_creates_areas_then_lines_then_equipment_with_correct_parents()
    {
        var sink = new RecordingFolderSink();
        var applier = new Phase7Applier(sink, NullLogger<Phase7Applier>.Instance);

        var composition = new Phase7CompositionResult(
            UnsAreas: new[] { new UnsAreaProjection("area-1", "Plant North") },
            UnsLines: new[] { new UnsLineProjection("line-1", "area-1", "Cell A") },
            EquipmentNodes: new[] { new EquipmentNode("eq-1", "Pump-1", "line-1") },
            DriverInstancePlans: Array.Empty<DriverInstancePlan>(),
            ScriptedAlarmPlans: Array.Empty<ScriptedAlarmPlan>());

        applier.MaterialiseHierarchy(composition);

        var calls = sink.Calls;
        calls.Count.ShouldBe(3);
        calls[0].ShouldBe(("area-1", null, "Plant North"));
        calls[1].ShouldBe(("line-1", "area-1", "Cell A"));
        calls[2].ShouldBe(("eq-1", "line-1", "Pump-1"));
    }

    [Fact]
    public void MaterialiseHierarchy_orphan_equipment_hangs_under_root()
    {
        var sink = new RecordingFolderSink();
        var applier = new Phase7Applier(sink, NullLogger<Phase7Applier>.Instance);

        var composition = new Phase7CompositionResult(
            UnsAreas: Array.Empty<UnsAreaProjection>(),
            UnsLines: Array.Empty<UnsLineProjection>(),
            EquipmentNodes: new[] { new EquipmentNode("eq-orphan", "Orphan", UnsLineId: "") },
            DriverInstancePlans: Array.Empty<DriverInstancePlan>(),
            ScriptedAlarmPlans: Array.Empty<ScriptedAlarmPlan>());

        applier.MaterialiseHierarchy(composition);

        sink.Calls.Single().ShouldBe(("eq-orphan", null, "Orphan"));
    }

    [Fact]
    public async Task MaterialiseHierarchy_against_real_SDK_node_manager_creates_folder_nodes()
    {
        await using var host = new OpcUaApplicationHost(
            new OpcUaApplicationHostOptions
            {
                ApplicationName = "OtOpcUa.Hierarchy",
                ApplicationUri = $"urn:OtOpcUa.Hierarchy:{Guid.NewGuid():N}",
                OpcUaPort = AllocateFreePort(),
                PublicHostname = "localhost",
                PkiStoreRoot = _pkiRoot,
            },
            NullLogger<OpcUaApplicationHost>.Instance);

        var sdkServer = new OtOpcUaSdkServer();
        await host.StartAsync(sdkServer, Ct);
        sdkServer.NodeManager.ShouldNotBeNull();

        var sink = new SdkAddressSpaceSink(sdkServer.NodeManager!);
        var applier = new Phase7Applier(sink, NullLogger<Phase7Applier>.Instance);

        applier.MaterialiseHierarchy(new Phase7CompositionResult(
            UnsAreas: new[] { new UnsAreaProjection("area-A", "Area A"), new UnsAreaProjection("area-B", "Area B") },
            UnsLines: new[] { new UnsLineProjection("line-1", "area-A", "Line 1") },
            EquipmentNodes: new[] { new EquipmentNode("eq-1", "Eq 1", "line-1"), new EquipmentNode("eq-2", "Eq 2", "line-1") },
            DriverInstancePlans: Array.Empty<DriverInstancePlan>(),
            ScriptedAlarmPlans: Array.Empty<ScriptedAlarmPlan>()));

        sdkServer.NodeManager!.FolderCount.ShouldBe(5); // 2 areas + 1 line + 2 equipment

        // Idempotent: re-applying with the same composition doesn't create duplicates.
        applier.MaterialiseHierarchy(new Phase7CompositionResult(
            UnsAreas: new[] { new UnsAreaProjection("area-A", "Area A"), new UnsAreaProjection("area-B", "Area B") },
            UnsLines: new[] { new UnsLineProjection("line-1", "area-A", "Line 1") },
            EquipmentNodes: new[] { new EquipmentNode("eq-1", "Eq 1", "line-1"), new EquipmentNode("eq-2", "Eq 2", "line-1") },
            DriverInstancePlans: Array.Empty<DriverInstancePlan>(),
            ScriptedAlarmPlans: Array.Empty<ScriptedAlarmPlan>()));

        sdkServer.NodeManager!.FolderCount.ShouldBe(5);
    }

    private static int AllocateFreePort()
    {
        using var listener = new System.Net.Sockets.TcpListener(System.Net.IPAddress.Loopback, 0);
        listener.Start();
        var port = ((System.Net.IPEndPoint)listener.LocalEndpoint).Port;
        listener.Stop();
        return port;
    }

    public void Dispose()
    {
        if (Directory.Exists(_pkiRoot))
        {
            try { Directory.Delete(_pkiRoot, recursive: true); }
            catch { /* best-effort */ }
        }
    }

    private sealed class RecordingFolderSink : IOpcUaAddressSpaceSink
    {
        private readonly ConcurrentQueue<(string NodeId, string? Parent, string DisplayName)> _calls = new();
        public List<(string NodeId, string? Parent, string DisplayName)> Calls => _calls.ToList();

        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc) { }
        public void WriteAlarmState(string alarmNodeId, bool active, bool acknowledged, DateTime sourceTimestampUtc) { }
        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName)
            => _calls.Enqueue((folderNodeId, parentNodeId, displayName));
        public void RebuildAddressSpace() { }
    }
}